CN111333021B - Single-mass-block planar three-axis MEMS (micro-electromechanical systems) inertial sensor and preparation method thereof - Google Patents

Abstract

The invention discloses a single-mass plane three-axis MEMS inertial sensor, comprising a bottom plate, a cavity structure layer, a mass block and a cantilever beam structure layer, and a top plate that are sequentially bonded from bottom to top; a cavity on the bottom surface of the cavity structure layer The bonding ring on the bottom surface of the substrate is gold-gold bonded with the bottom bonding ring on the top surface of the substrate; the bottom surface of the cantilever beam fixing frame is gold-silicon bonded with the bonding ring on the top surface of the cavity substrate on the top surface of the cavity structure layer, and each cantilever beam is suspended in the air above the cavity and the mass block is suspended in the cavity; the grounding lead-out electrode on the bottom surface of the top plate is gold-gold bonded with the grounding electrode on the top surface of the fixed frame of the cantilever beam to finally form a hermetically sealed structure. The overall structure of the invention is simple and the preparation The process is simple and the sensing sensitivity and sensing accuracy are high.

Description

Single-mass plane three-axis MEMS inertial sensor and preparation method thereof

technical field

The invention relates to an inertial sensor, in particular to a single-mass plane three-axis MEMS inertial sensor.

Background technique

MEMS inertial sensors are based on micro-mechanical electronics (MEMS) technology and are fabricated by micro-machining technology. They have the advantages of small size, light weight, low energy consumption, and high reliability. They are widely used in aerospace, automotive, consumer electronics, industrial control and other fields.

The MEMS inertial sensors in the current technology mainly include accelerometers and gyroscopes. MEMS accelerometers include single-axis accelerometers and multi-axis accelerometers, which are used to sense the motion of a single axis or multiple orthogonal axes of an object that is moving in linear acceleration. Acceleration, MEMS gyroscopes also include single-axis gyroscopes and multi-axis gyroscopes, which are used to sense the angular displacement or angular velocity information of a single axis or multiple orthogonal axes of a rotating angular motion object.

However, in practical applications, especially when monitoring the inertial motion state of a planar moving object, it is often necessary to simultaneously sense the in-plane horizontal linear motion and the in-plane horizontal rotational angular motion of the moving object. Although the orthogonal assembly of multiple single-axis accelerometers and single-axis gyroscopes can be used to achieve this purpose, the sensing component thus constituted is complex in structure and large in size, and at the same time the orthogonal assembly of multiple axial accelerometers and gyroscopes The error will bring greater noise of the output signal and affect the detection accuracy.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a single-mass plane three-axis MEMS inertial sensor and a preparation method thereof. It is simple, the preparation process is simple, and the sensing sensitivity and sensing accuracy are high.

The object of the present invention is achieved as follows: a single-mass plane three-axis MEMS inertial sensor, characterized in that it comprises a bottom plate (1), a cavity structure layer (2), a mass and Cantilever beam structure layer (3), roof (4);

The bottom plate (1) comprises a bottom plate substrate (11), four groups of side capacitor output electrodes (12) symmetrically distributed on the bottom surface of the bottom surface of the bottom plate with respect to the center thereof, and four groups of side capacitor external electrodes symmetrically distributed on the top surface of the bottom plate substrate with respect to the center thereof The bottom lead-out electrode (13), the bottom plate bonding ring (14) of the bottom lead-out electrode (13) surrounding four groups of side capacitor external electrodes on four sides of the top surface of the bottom plate substrate, and 8 bottom plate metal through holes (15) penetrating the bottom plate substrate;

The cavity structure layer (2) comprises a cavity substrate (21), a regular octagonal prism cavity (22) penetrating the middle of the cavity substrate, and four groups of four groups arranged alternately on four inner surfaces of the cavity (22) on the front, back, left, right, and right of the cavity (22). The side capacitor external electrodes (23), the four sets of side capacitor external electrodes whose bottom surface faces the four sets of side capacitor external electrodes (24), and the four sets of side capacitor external electrodes on the bottom surface of the cavity substrate are surrounded by four sets of side capacitor external electrodes. 24) bonding ring (25) on the bottom surface of the cavity substrate and a bonding ring (26) on the top surface of the cavity substrate surrounding the four sides of the top surface of the cavity substrate;

The mass block and the cantilever beam structure layer (3) comprise a regular octagonal mass block (31), four side capacitor inner electrodes (32) which are alternately covered on four sides of the mass block, front, back, left and right, and a bottom surface of the mass block is covered with four inner capacitor electrodes (32). The inner electrode lead-out electrode (33) of the side capacitor, the mass metal through hole (34) penetrating the center of the mass the ground electrode (37) on the top surface of the cantilever beam and the top surface of the cantilever beam fixing frame;

The top plate (4) comprises a top plate substrate (41), a top plate cavity (42) in the middle of the bottom surface of the top plate substrate, grounding lead-out electrodes (43) covering the four sides of the bottom surface of the top plate substrate, and four sides of the top surface of the top plate substrate are symmetrically distributed with respect to the center thereof. 4 grounding output electrodes (44) and 4 top plate metal through holes (45) penetrating through the top plate substrate;

The bottom surface bonding ring (25) of the cavity substrate on the bottom surface of the cavity structure layer (2) is gold-gold bonded with the bottom plate bonding ring (15) on the top surface of the bottom plate (1); The bottom surface is gold-silicon bonded with a bonding ring (26) on the top surface of the cavity substrate on the top surface of the cavity structure layer (2), each cantilever beam is suspended on the cavity (21) and the mass block (31) is suspended in the air In the cavity (21); the grounding lead-out electrode (43) on the bottom surface of the top plate (4) is gold-gold bonded with the grounding electrode (44) on the top surface of the cantilever beam fixing frame (36) to finally form a hermetically sealed structure.

As a further limitation of the present invention, the bottom plate substrate (11) is a substrate with a square cross-section, and correspondingly, the bottom plate bonding ring (14) is a rectangular ring with an inner and outer cross-section;

Each group of side capacitor output electrodes includes two parallel side capacitor output electrodes (12), and each side capacitor output electrode (12) is a rectangular electrode of the same shape;

The lower lead-out electrodes of each group of side capacitor outer electrodes comprise two parallel side-capacitance outer electrodes lower lead-out electrodes (13), and the lower lead-out electrodes (13) of each side capacitor outer electrode are rectangular electrodes of the same shape;

Each side capacitor output electrode (12) is directly opposite to the lower lead-out electrode (13) of one side capacitor outer electrode, and is connected by a bottom metal through hole (15).

As a further limitation of the present invention, the cavity substrate (21) is a thick substrate with a square outer edge, and correspondingly, the bottom surface bonding ring (25) of the cavity substrate and the top surface bonding ring (26) of the cavity substrate are Both are rectangular rings with inner and outer cross-sections;

Each group of side capacitor outer electrodes includes two side capacitor outer electrodes (23) in parallel, each side capacitor outer electrode (23) is a rectangular electrode of the same shape, and the height of each side capacitor outer electrode (23) is the same as the cavity (22) The total width of the two side capacitor external electrodes (23) and their gaps in each group of side capacitor external electrodes is the same as the total width of the mass block and the regular octagonal prism-shaped mass block (31) in the cantilever beam structure layer (3). The widths of the inner electrodes (32) of the side capacitors are the same;

The lead-out electrodes on the outer electrodes of the side capacitors of each group include two parallel lead-out electrodes (24) on the outer electrodes of the side capacitors, and the lead-out electrodes (24) on the outer electrodes of the respective side capacitors are rectangular electrodes of the same shape, and the outer electrodes of the respective side capacitors The inner end of the upper lead-out electrode (24) is connected with the lower end of the corresponding side capacitor outer electrode (23).

As a further limitation of the present invention, the upper end of each side capacitor inner electrode (32) is flush with the lower surface of each S-shaped cantilever beam (35), and the lower end of each side capacitor inner electrode (32) is flush with the inner side of the side capacitor. The outer edges of the electrode lead-out electrodes (33) are connected, and the mass metal through holes (34) are connected to the side capacitor inner electrode lead-out electrodes (33) on the bottom surface of the mass block and the ground electrode (37) on the top surface of the mass block;

The cantilever beam fixing frame (36) is a hollow frame with an inner square and an outer square;

Each S-shaped cantilever beam (35) includes several radial arms (351), several transverse arms (352), an inner radial support arm (353) and an outer radial support arm (354); Each radial arm and each transverse arm have the same length and the same width, and the length of each radial arm and each transverse arm is at least 4 times its width; each inner radial support arm and each outer diameter The radial support arms have the same length and the same width, the length of each inner radial support arm and each outer radial support arm is not greater than its width, and the length of each inner radial support arm and each outer radial support arm is The width is not less than 1/2 of the length of the transverse arm; the radial arms, transverse arms, inner radial support arms, and outer radial support arms have the same thickness, and each radial arm, transverse arm, inner diameter The thickness of the lateral support arm and the outer radial support arm is at least twice the width of the radial arm or lateral arm;

In each S-shaped cantilever beam, the inner radial support arm, several transverse arms, several radial arms, and outer radial support arms are connected orthogonally in turn, wherein each transverse arm and each radial arm are connected orthogonally in turn, so The S-shaped cantilever beams are alternately connected to the center of the top ends of the front, rear, left and right sides of the mass block through the inner ends of the inner radial support arms, and the S-shaped cantilever beams are alternately connected to the outer ends of the outer radial support arms. The cantilever beam fixing frame is at the center of the inner top of the front, rear, left and right sides, and the top surface of each S-shaped cantilever beam is flush with the top surface of the mass block and the top surface of the cantilever beam fixing frame.

As a further limitation of the present invention, the top plate substrate (41) is a substrate with a square outer edge, and correspondingly, the grounding lead-out electrodes (43) on the four sides of the bottom surface of the top plate substrate are rectangular rings with inner and outer cross-sections;

The cross section of the top plate cavity (42) is exactly the same as the cross section of the hollow part of the cantilever beam fixing frame (36), and the depth of the top plate cavity (42) is half of the thickness of the top plate base plate (41);

Each grounding output electrode (44) is a rectangular electrode of the same shape, and the four top metal through holes (45) are respectively connected to the four grounding output electrodes (44) and the grounding lead-out electrode (43).

As a further limitation of the present invention, the bottom plate substrate (11), the cavity substrate (21), the cantilever beam fixing frame (38) and the top plate substrate (41) have square outer edges with the same side length;

the bottom surface bonding ring (14), the bonding ring (25) on the bottom surface of the cavity substrate, the bonding ring (26) on the top surface of the cavity substrate, the bottom surface of the cantilever beam fixing frame (36) and the cantilever beam fixing frame ( 36) The grounding lead-out electrodes (43) on the top surface and the bottom surface of the top plate substrate (41) are identical;

Each electrode, each bonding ring and the substrate where it is located, and between each metal through hole and the substrate that penetrates through are electrically isolated by an insulating layer (5);

The substrate material of the top plate (1), the cavity structure layer (2) and the bottom plate (4) is silicon single crystal, the substrate for making the mass block and the cantilever beam structure layer (3) is an SOI substrate, and each electrode, each The material of the bonding ring and each metal through hole is gold, and the material of the insulating layer (5) is silicon dioxide or silicon nitride.

As a further limitation of the present invention, the mass block is suspended in the cavity, and the gap between the outer surface of the mass block and the inner surface of the cavity is the in-plane horizontal offset of the mass block relative to the cavity front and rear, and the in-plane horizontal offset left and right , the horizontal rotation space in the plane;

In the single-mass plane three-axis MEMS inertial sensor structure, the 4 side capacitor inner electrodes and the opposite 8 side capacitor outer electrodes form 8 side capacitors (6), wherein the two sides located on the front side of the mass block Capacitors (61, 62) form a first sensing capacitor pair, two side capacitors (63, 64) located on the rear side of the mass block form a second sensing capacitor pair, and two side capacitors (65, 64) located on the left side of the mass block 66) A third sensing capacitor pair is formed, and the two side capacitors (67, 68) located on the right side of the mass block form a fourth sensing capacitor pair.

As a further limitation of the present invention, in static state, the 8 outer side surfaces of the mass block suspended in the cavity are respectively parallel to, facing each other and keep the same distance with the 8 opposite inner side surfaces of the cavity, the bottom surface of the mass block and the bottom plate The top surface of and the top surface of the mass block are parallel to the top surface of the top plate cavity and maintain the initial distance;

Correspondingly, the 4 side capacitor inner electrodes on the outer surface of the mass block are respectively parallel to, facing each other and keep the same gap width with the opposite 4 groups of side capacitor outer electrodes, forming the static insulation gap of the 8 side capacitors, the 8 side capacitors. With the same static capacitance value, the 8 side capacitance output ports formed by each side capacitance output electrode and each ground output electrode output the same static capacitance value signal.

As a further limitation of the present invention, in the single-mass planar three-axis MEMS inertial sensor structure, four symmetrically distributed S-shaped cantilever beams support the mass-mass, and each S-shaped cantilever beam is suspended on the cavity and makes the mass-mass Suspended in a cavity, where:

The radial arms and transverse arms of each S-shaped cantilever beam are long and narrow thick beams with the same length, which are easy to produce in-plane radial deformation and in-plane transverse deformation, but are not easy to produce out-of-plane bending deformation;

The inner radial support arm and the outer radial support arm of each S-shaped cantilever beam are short and wide thick beams, which are not prone to in-plane bending deformation and out-of-plane bending deformation.

The above structural features make it easy to generate in-plane horizontal forward (or backward) offset, in-plane horizontal left (or right) offset and In-plane horizontal left (or right) deflection is not easy to produce out-of-plane vertical upward (downward) deflection, out-of-plane forward (or backward) deflection, and out-of-plane left (or right) deflection, that is, the single mass The planar three-axis MEMS inertial sensor is only sensitive to in-plane horizontal forward (or backward) linear acceleration motion, in-plane horizontal left (or right) linear acceleration motion, and in-plane horizontal left-handed (or right-handed) angular motion, while the opposite Out-of-plane linear acceleration motion and out-of-plane angular motion are insensitive, realizing the in-plane horizontal linear acceleration motion and in-plane horizontal angular motion that the single-mass planar three-axis MEMS inertial sensor is sensitive to and unexpected additional out-of-plane linear acceleration motion and out-of-plane motion. Decoupling of rotational angular motion.

A preparation method of a single-mass plane three-axis inertial sensor using MEMS technology, comprising the following steps:

1. Making the bottom plate;

(1-1) Thermal oxidation or LPCVD of the top surface of the silicon single crystal substrate to form an oxide insulating layer covering the top surface of the substrate;

(1-2) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the end face of the metal through hole of the base plate to be formed is located;

(1-3) Wet etching, removing the oxide insulating layer in the area where the end face of the metal through hole of the base plate to be made is located, and removing the glue;

(1-4) dry etching, forming through silicon vias through the substrate, removing glue, and removing the oxide insulating layer on the top surface of the substrate;

(1-5) Double-sided thermal oxidation or LPCVD of the above-mentioned substrate to form an oxide insulating layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the TSV;

(1-6) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the through-silicon hole is located;

(1-7) magnetron sputtering, covering titanium film and gold film successively on the inner wall of the above-mentioned through-silicon hole, and removing the glue to obtain each bottom plate metal through-hole;

(1-8) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the lead electrode and the base plate bonding ring are located under the outer electrode of the side capacitor to be fabricated;

(1-9) magnetron sputtering, covering the titanium film and the gold film in turn;

(1-10) Remove the glue, together with removing the titanium-gold film on the photoresist film covering the lead-out electrodes under the external electrodes of the side capacitors and the area where the bonding ring of the base plate is located, to obtain the lead-out electrodes and the bottom plate under the external electrodes of each side capacitor bonding ring;

(1-11) Coat the bottom surface of the above-mentioned substrate with photoresist, expose and develop, and remove the photoresist film in the area where the output electrode of the side capacitor to be fabricated is located;

(1-12) Magnetron sputtering, covering the titanium film and the gold film in turn;

(1-13) Remove glue, together with removing the titanium-gold film covering the photoresist film outside the area where the side capacitor output electrodes are located, to obtain each side capacitor output electrode, and complete the production of the bottom plate;

2. Make a cavity structure layer;

(2-1) Thermal oxidation or LPCVD of the bottom surface of the silicon single crystal thick substrate to form an oxide insulating layer covering the bottom surface of the substrate;

(2-2) Coat the bottom surface of the silicon single crystal thick substrate with photoresist, expose and develop, and remove the photoresist film in the area where the end face of the outer electrode of the side capacitor to be fabricated is located;

(2-3) Wet etching to remove the oxide insulating layer in the area where the end face of the outer electrode of the capacitor to be fabricated is located;

(2-4) dry etching, forming a side capacitor outer electrode groove through the substrate, removing the glue, and removing the oxide insulating layer on the bottom surface of the substrate;

(2-5) Double-sided thermal oxidation or LPCVD of the above-mentioned substrate to form an oxide insulating layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the outer electrode trench of the side capacitor;

(2-6) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the outer electrode groove of the side capacitor is located;

(2-7) magnetron sputtering titanium, covering the inner wall of the outer electrode groove of the side capacitor, then magnetron sputtering gold, filling the outer electrode groove of the side capacitor, removing the glue, and obtaining the outer electrode of each side capacitor;

(2-8) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the lead-out electrode on the side electrode to be fabricated and the bonding ring on the bottom surface of the cavity substrate are located;

(2-9) magnetron sputtering, covering the titanium film and the gold film in turn;

(2-10) Remove the glue, together with removing the titanium-gold film covering the lead-out electrodes on the external electrodes of the side capacitors and the photoresist film outside the area where the bonding ring on the bottom surface of the cavity substrate is located, to obtain the lead-out electrodes on the external electrodes of each side capacitor The electrode and the bonding ring on the bottom surface of the cavity substrate;

(2-11) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the bonding ring on the top surface of the cavity substrate to be fabricated is located;

(2-12) magnetron sputtering, covering titanium film, gold film and titanium film in sequence;

(2-13) Degumming, together with removing the titanium-gold-titanium film covering the photoresist film outside the area where the bonding ring on the top surface of the cavity substrate is located, to obtain the bonding ring on the top surface of the cavity substrate;

(2-14) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the cavity to be formed is located;

(2-15) Dry etching, sequentially removing the oxidized insulating layer on the top surface of the substrate, the silicon single crystal layer and the oxidized insulating layer on the bottom surface of the substrate in the area where the cavity is located, to form a cavity through the substrate, and make the side capacitance on the side of the cavity The outer electrode is exposed to complete the fabrication of the cavity structure layer;

3. Make the mass block and the cantilever beam structure layer;

(3-1) Prepare an SOI substrate, the SOI substrate is a silicon single crystal surface layer, a buried oxygen layer and a silicon single crystal support layer in order from top to bottom;

(3-2) Thermal oxidation or LPCVD of the top surface of the substrate to form an oxide insulating layer covering the top surface of the substrate;

(3-3) Coating photoresist on the top surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the region where the end face of the metal through hole of the mass block to be prepared is located;

(3-4) Wet etching, removing the oxide insulating layer in the area where the end face of the metal through hole of the mass block to be made is located, and removing the glue;

(3-5) dry etching, forming through silicon vias penetrating the SOI substrate, removing glue, and removing the oxide insulating layer on the top surface of the substrate;

(3-6) Double-sided thermal oxidation or LPCVD of the above-mentioned SOI substrate to form an oxide insulating layer covering the top surface of the SOI substrate, the bottom surface of the SOI substrate and the inner wall of the TSV;

(3-7) Coating photoresist on the top surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the above-mentioned through-silicon hole is located;

(3-8) magnetron sputtering, sequentially covering the titanium film and the gold film on the inner wall of the above-mentioned through-silicon hole, and removing the glue to obtain a mass metal through-hole;

(3-9) Coating photoresist on the top surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the ground electrode to be prepared is located;

(3-10) Magnetron sputtering, covering the titanium film and the gold film in turn;

(3-11) Remove the glue, together with removing the titanium-gold film covering the photoresist film outside the area where the ground electrode is located, to obtain a ground electrode;

(3-12) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the end face of the inner electrode of the side capacitor to be fabricated is located;

(3-13) wet etching, removing the oxide insulating layer on the bottom surface of the SOI substrate in the region where the end face of the inner electrode of the side capacitor to be fabricated is located;

(3-14) dry etching, removing the SOI substrate silicon single crystal support layer in the area where the inner electrode of the side capacitor to be fabricated is located, ending at the buried oxygen layer of the SOI substrate, obtaining the inner electrode groove of the side capacitor, and removing the glue;

(3-15) Thermal oxidation or LPCVD, covering the inner wall of the above-mentioned side capacitor inner electrode trench with an oxide insulating layer;

(3-16) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the inner electrode groove of the side capacitor is located;

(3-17) magnetron sputtering titanium, covering the inner wall of the inner electrode groove of the side capacitor, then magnetron sputtering gold, filling the inner electrode groove of the side capacitor, removing the glue, and obtaining the inner electrode of each side capacitor;

(3-18) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the side capacitor inner electrode leads out the electrode;

(3-19) magnetron sputtering, covering the titanium film and the gold film in turn;

(3-20) Glue removal, together with removing the titanium-gold film on the photoresist film outside the area where the side capacitor inner electrode lead-out electrode is located, to obtain the side capacitor inner electrode lead-out electrode;

(3-21) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film outside the area where the inner electrode extraction electrode of the capacitor on the bottom surface of the mass block to be produced is located;

(3-22) Wet etching to remove the oxidized insulating layer on the bottom surface of the SOI substrate outside the area where the lead-out electrodes of the capacitor inner electrodes are located on the bottom surface of the mass block to be fabricated;

(3-23) Dry etching, remove the SOI substrate silicon single crystal support layer outside the area where the mass block to be fabricated is located, stop at the position corresponding to the bottom surface of the cantilever beam fixing frame to be fabricated, remove the glue, and remove the oxidation on the bottom surface of the substrate Insulation;

(3-24) LPCVD, covering an oxide insulating layer on the bottom surface of the above-mentioned SOI substrate;

(3-25) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area between the mass block to be manufactured and the cantilever beam fixing frame to be manufactured;

(3-26) Wet etching to remove the oxide insulating layer in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated;

(3-27) Dry etching, removing the SOI substrate silicon single crystal support layer in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated, ending at the buried oxygen layer of the SOI substrate, so that each side of the mass block side The inner electrode of the capacitor is exposed, the lower structure of the mass block is obtained, and the glue is removed;

(3-28) Wet etching to remove the buried oxygen layer of the SOI substrate in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated, as well as the oxide insulation on the bottom surface of the mass block, the side surface of the mass block and the bottom surface of the cantilever beam fixing frame layer, forming the bottom surface of each cantilever beam and the bottom surface of the cantilever beam fixing frame;

(3-29) Coat the photoresist on the top surface of the SOI substrate, expose and develop, and remove the photoresist film outside the area where the ground electrode obtained in steps (3-9) to (3-11) is located;

(3-30) Dry etching, sequentially removing the oxide insulating layer on the top surface of the SOI substrate and the silicon single crystal surface layer of the SOI substrate outside the area where the ground electrode is located, and removing the glue to obtain the mass block, each cantilever beam and the cantilever beam fixing frame , to complete the production of the mass block and the cantilever beam structure layer;

4. Make the top plate;

(4-1) Thermal oxidation or LPCVD of the top surface of the silicon single crystal substrate to form an oxide insulating layer covering the top surface of the substrate;

(4-2) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the end face of the metal through hole of the top plate to be formed is located;

(4-3) Wet etching, removing the oxide insulating layer in the area where the end face of the metal through hole of the top plate to be made is located, and removing the glue;

(4-4) dry etching, forming through silicon vias, removing glue, and removing the oxide insulating layer on the top surface of the substrate;

(4-5) Double-sided thermal oxidation or LPCVD, forming an oxide insulating layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the TSV;

(4-6) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the above-mentioned through-silicon hole is located;

(4-7) Magnetron sputtering, sequentially covering titanium film and gold film on the inner wall of the above-mentioned through-silicon hole, and removing the glue to obtain each top plate metal through-hole;

(4-8) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the ground output electrode to be prepared is located;

(4-9) Magnetron sputtering, covering titanium film and gold film;

(4-10) removing the glue, together with removing the titanium-gold film covering the photoresist film outside the area where the grounded output electrode is located, to obtain each grounded output electrode;

(4-11) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the grounding lead-out electrode to be prepared is located;

(4-12) Magnetron sputtering, covering titanium film and gold film;

(4-13) Glue removal, together with removing the titanium-gold film covering the photoresist film outside the area where the grounding lead-out electrode is located, to obtain the grounding lead-out electrode;

(4-14) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the cavity of the top plate to be formed is located;

(4-15) Wet etching to remove the oxide insulating layer in the region where the cavity of the top plate to be fabricated is located;

(4-16) dry etching, removing the silicon single crystal layer on the bottom surface of the above-mentioned substrate where the top plate cavity to be formed is located, and ending at a position where the thickness of the substrate is half, to obtain the top plate cavity, and completing the fabrication of the top plate;

The titanium film sputtered in the above-mentioned preparation steps of each electrode and each metal through hole is used as the tackifying layer; the lower layer titanium film sputtered in the preparation step of the bonding ring on the top surface of the cavity substrate is used as the tackifying layer, and the sputtered upper layer is used as the tackifying layer. Titanium films are used as adhesion promoters and barrier layers.

5. Structural layer bonding;

(5-1) Align the bonding ring on the top surface of the cavity substrate on the top surface of the cavity structure layer with the bottom surface of the cantilever beam fixing frame, put it into the bonding machine, and heat up from room temperature to the set bonding Temperature, maintain the set bonding time under the set bonding pressure, and then naturally cool down to room temperature to complete the gold-silicon bonding between the cavity structure layer and the mass block and the cantilever structure layer;

(5-2) Align the base plate bonding ring on the top surface of the base plate and the lead-out electrodes on the outer electrodes of each side capacitor with the bonding ring on the bottom surface of the cavity substrate on the bottom surface of the cavity structure layer and the bottom lead-out electrodes of the outer electrodes of each side capacitor. Then put it into the bonding machine, raise the temperature from room temperature to the set bonding temperature, keep the set bonding time under the set bonding pressure, and then naturally cool down to room temperature to complete the bonding between the bottom plate and the cavity structure layer. gold-gold bonding;

(5-3) Align and fit the grounding lead-out electrode on the bottom surface of the top plate and the grounding electrode on the top surface of the cantilever beam fixing frame, put it into the bonding machine, and raise the temperature from room temperature to the set bonding temperature. The set bonding time is maintained under the bonding pressure, and then the temperature is naturally cooled to room temperature to complete the gold-gold bonding of the top plate and the cantilever beam fixed frame.

The working principle of the present invention is as follows:

1. When the single-mass planar three-axis MEMS inertial sensor is only sensitive to in-plane horizontal forward (or backward) linear acceleration motion, the mass is generated horizontally backward (or forward) in the plane due to inertia relative to the cavity. Offset, the outer electrodes of the respective side capacitors in the first sensing capacitor pair and the second sensing capacitor pair are offset horizontally forward (or backward) in-plane relative to the inner electrodes thereof, wherein:

The outer electrodes of the two side capacitors in the first sensing capacitor pair are displaced forward (or approached backward) horizontally in-plane relative to their inner electrodes, and the overlapping areas of the inner and outer electrodes of the two side capacitors remain unchanged, while the inner and outer electrodes remain unchanged. As the electrode gap width increases (or decreases), the capacitance values of the two side capacitors decrease (or increase) accordingly;

In the second sensing capacitor pair, the outer electrodes of the two side capacitors are shifted horizontally forward (or backward) relative to their inner electrodes, and the overlapping areas of the inner and outer electrodes of the two side capacitors remain unchanged, while As the electrode gap width decreases (or increases), the capacitance values of the two side capacitors increase (or decrease) accordingly;

The change in capacitance value of each side capacitor corresponds to the change in the width of the gap between its inner and outer electrodes, that is, the offset corresponding to the in-plane horizontal forward (or backward) offset of the outer electrode of each side capacitor relative to its inner electrode. , that is, the acceleration corresponding to the in-plane horizontal forward (or backward) linear acceleration motion sensed by the single-mass planar three-axis MEMS inertial sensor.

Accordingly, by actually measuring the capacitance value of each side capacitance in the first sensing capacitance pair or the second sensing capacitance pair through the corresponding side capacitance output electrodes, the in-plane sensed by the single-mass planar triaxial MEMS inertial sensor can be calculated. The acceleration of the horizontal forward (or backward) linear acceleration movement.

2. When the single-mass planar three-axis MEMS inertial sensor is only sensitive to the in-plane horizontal left (or right) linear acceleration movement, the mass is caused by inertia relative to the cavity to generate in-plane horizontal to the right (or left) Offset, the outer electrodes of the respective side capacitors in the third sensing capacitor pair and the fourth sensing capacitor pair are horizontally offset to the left (or right) in-plane relative to the inner electrodes, wherein:

The outer electrodes of the two side capacitors in the third sensing capacitor pair are shifted to the left (or approach the right) horizontally in-plane relative to the inner electrodes, and the overlapping areas of the inner and outer electrodes of the two side capacitors remain unchanged, while the inner and outer electrodes remain unchanged. As the electrode gap width increases (or decreases), the capacitance values of the two side capacitors decrease (or increase) accordingly;

The outer electrodes of the two side capacitors of the fourth sensing capacitor pair are horizontally shifted to the left (or away from the right) relative to their inner electrodes, and the overlapping areas of the inner and outer electrodes of the two side capacitors remain unchanged, while the inner and outer electrodes are not changed. As the electrode gap width decreases (or increases), the capacitance values of the two side capacitors increase (or decrease) accordingly;

The change in capacitance value of each side capacitor corresponds to the change in the width of the gap between its inner and outer electrodes, that is, the offset corresponding to the in-plane horizontal left (or right) offset of the outer electrode of each side capacitor relative to its inner electrode. , that is, the acceleration corresponding to the in-plane horizontal leftward (or rightward) linear acceleration motion sensed by the single-mass planar three-axis MEMS inertial sensor.

Accordingly, by actually measuring the capacitance value of each side capacitance in the third sensing capacitance pair or the fourth sensing capacitance pair through the corresponding side capacitance output electrodes, the in-plane sensed by the single-mass planar triaxial MEMS inertial sensor can be calculated. The acceleration of the horizontal left (or right) linear acceleration movement.

3. When the single-mass planar three-axis MEMS inertial sensor is only sensitive to in-plane horizontal left-handed (or right-handed) angular motion, the mass is deflected in-plane horizontally to the right (or left-handed) due to inertia relative to the cavity. The outer electrode of each side capacitance in the sensing capacitance pair is deflected horizontally in-plane left-handed (or right-handed) relative to its inner electrode, wherein:

In each sensing capacitor pair, the outer electrodes of the side capacitors located on the front side of the deflection direction are moved out of the plane horizontally to the left (or right) relative to the inner electrodes, and the overlapping area of the inner and outer electrodes of each side capacitor is reduced and the gap between the inner and outer electrodes The width decreases linearly along the deflection direction, and the capacitance value of each side capacitor changes accordingly;

The outer electrodes of the side capacitors located on the rear side of the deflection direction in each sensing capacitor pair are moved in-plane horizontally to the left (or right) relative to the inner electrodes, and the overlapping area of the inner and outer electrodes of each side capacitor remains unchanged. The width of the gap decreases linearly along the deflection direction, and the capacitance value of each side capacitor changes accordingly;

Only the side capacitances located on the rear side of the deflection direction in each sensing capacitance pair are considered, and the capacitance value change of each side capacitance only corresponds to the mutual inclination angle between its inner and outer electrodes, that is, corresponding to the width of the inner and outer electrode gaps linearly along the deflection direction. The amount of change, that is, the angular deflection corresponding to the in-plane horizontal left-handed (or right-handed) deflection of the outer electrodes of each side capacitance relative to the inner electrodes, that is, corresponding to the single-mass plane three-axis MEMS inertial sensor sensed The angular velocity of in-plane horizontal left-handed (or right-handed) angular motion.

Accordingly, the in-plane horizontal left-handed (or right-handed) angle sensed by the single-mass planar three-axis MEMS inertial sensor can be calculated by actually measuring the capacitance value of the relevant side capacitance of each sensing capacitor pair through the corresponding side capacitance output electrode Angular velocity of movement.

4. When the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to in-plane horizontal forward (or backward) linear acceleration motion, in-plane horizontal leftward (or right) linear acceleration motion, and in-plane horizontal left rotation (or When the angular motion is to the right, the mass will simultaneously generate an in-plane horizontal backward (or forward) offset, an in-plane horizontal right (or left) offset, and an in-plane horizontal right-hand (or Left-handed) deflection, the external electrodes of each side capacitor are simultaneously shifted in-plane horizontal forward (or backward), left-handed (or right) in-plane horizontal, and in-plane horizontal left-handed (or right-handed) relative to their inner electrodes. rotation) deflection.

According to the principle of motion independence, the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to in-plane horizontal forward (or backward) linear acceleration, in-plane horizontal left (or right) linear acceleration and in-plane horizontal acceleration. The horizontal left-handed (or right-handed) angular movement causes the outer electrodes of the capacitors on each side to simultaneously shift the in-plane horizontal forward (or backward), the in-plane horizontal left (or right) offset relative to the inner electrodes, and The in-plane horizontal left-handed (or right-handed) deflection can be regarded as the plane inertial motion of the above-mentioned three axial directions to which the single-mass plane three-axis MEMS inertial sensor is respectively sensitive, so that the outer electrodes of each side capacitance are respectively relative to its inner electrodes. The superposition of the in-plane horizontal forward (or backward) offset, the in-plane horizontal left (or right) offset, and the in-plane horizontal left (or right) deflection, where:

The single-mass planar three-axis MEMS inertial sensor is only sensitive to the in-plane horizontal forward (or backward) linear acceleration motion so that the width of the inner and outer electrode gaps of the two side capacitors in the first sensing capacitor pair increases (or decreases). small), at the same time, the width of the inner and outer electrode gaps of the two side capacitors in the second sensing capacitor pair is reduced (or increased), and the third sensing capacitor pair and the fourth sensing capacitor pair are located in the movement direction at the same time. The overlapping area of the inner and outer electrodes of each side capacitor on the front side is reduced. The above side capacitors are changed from the parallel-plate capacitor structure in static state to the parallel-plate capacitors with changes in the gap width of the inner and outer electrodes or changes in the overlapping area of the inner and outer electrodes. structure.

The single-mass planar three-axis MEMS inertial sensor is only sensitive to the in-plane horizontal left (or right) linear acceleration motion so that the width of the inner and outer electrode gaps between the two side capacitors in the third sensing capacitor pair increases (or decreases). small), at the same time, the width of the inner and outer electrode gaps of the two side capacitors in the fourth sensing capacitor pair is reduced (or increased), and the first sensing capacitor pair and the second sensing capacitor pair are located in the moving direction at the same time. The overlapping area of the inner and outer electrodes of each side capacitor on the front side is reduced. The above side capacitors are changed from the parallel-plate capacitor structure in static state to the parallel-plate capacitors with changes in the gap width of the inner and outer electrodes or changes in the overlapping area of the inner and outer electrodes. structure.

The single-mass planar three-axis MEMS inertial sensor is individually sensitive to in-plane horizontal left-handed (or right-handed) angular motion, so that each sensing capacitor is centered along the deflection direction. At the same time, the width of the inner and outer electrode gaps of each side capacitor on the front side of the deflection direction is centered along the deflection direction, and the width of the inner and outer electrodes decreases linearly along the deflection direction, and the overlapping area of the inner and outer electrodes decreases. The structures are respectively changed to a non-parallel plate capacitor structure in which the width of the inner and outer electrode gap changes linearly along the deflection direction or the width of the inner and outer electrode gap changes linearly along the deflection direction and the overlapping area of the inner and outer electrodes changes.

The single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to in-plane horizontal forward (or backward), in-plane horizontal left (or right) linear acceleration motion and in-plane horizontal left-hand (or right-hand) angle The movement causes its respective sensing capacitors to center the outer electrodes of the side capacitors located on the front side of the deflection direction relative to their inner electrodes to simultaneously generate an in-plane horizontal forward (or backward) offset, and an in-plane horizontal left (or right) Offset, in-plane horizontal left-handed (or right-handed) movement out of deflection, the width of the inner and outer electrode gaps of each side capacitor changes and the overlapping area of the inner and outer electrodes changes, and the width of the inner and outer electrode gaps changes linearly along the deflection direction, while making each sensing The outer electrode of the side capacitor located on the back side of the deflection direction in the capacitor pair simultaneously produces an in-plane horizontal forward (or backward) offset, an in-plane horizontal left (or right) offset, and an in-plane horizontal offset relative to its inner electrode. Left-handed (or right-handed) moves into the deflection, the overlapping area of the inner and outer electrodes of each side capacitor remains unchanged, but the width of the inner and outer electrode gap changes, and the width of the inner and outer electrode gap decreases linearly along the deflection direction. The capacitance structure change is a non-parallel plate capacitance structure in which the width of the inner and outer electrode gap changes linearly along the deflection direction and/or the width of the inner and outer electrode gap changes and/or the overlapping area of the inner and outer electrodes changes.

The above single-mass planar three-axis MEMS inertial sensors are respectively sensitive to in-plane horizontal forward (or backward), in-plane horizontal left (or right) linear acceleration motion, and in-plane horizontal left-handed (or right-handed) angular motion. The respectively formed parallel plate capacitor structure in which the inner and outer electrode gap widths change, the parallel plate capacitor structure in which the overlapping area of the inner and outer electrodes changes, and the non-parallel plate capacitor structure in which the inner and outer electrode gap widths change linearly along the deflection direction are equivalent to having Equivalent parallel plate capacitance with the same overlapping area of inner and outer electrodes in static state, the variation of the inner and outer electrode gap width of the equivalent parallel plate capacitance corresponding to each side capacitance relative to its static state corresponding to the change of the inner and outer electrode gap width respectively corresponds to the The single-mass planar three-axis MEMS inertial sensor is sensitive to the in-plane horizontal forward (or backward) linear acceleration motion, the in-plane horizontal left (or right) linear acceleration motion, and the in-plane horizontal left rotation (or right rotation) The angular movement causes the offset or deflection of the outer electrode of the relevant side capacitance relative to its inner electrode, that is, corresponding to the in-plane horizontal forward (or backward) straight line sensed by the single-mass planar three-axis MEMS inertial sensor Acceleration of acceleration motion, acceleration of in-plane horizontal left (or right) linear acceleration motion, and angular velocity of in-plane horizontal left-handed (or right-handed) angular motion.

The above single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to in-plane horizontal forward (or backward), in-plane horizontal left (or right) linear acceleration motion, and in-plane horizontal left-handed (or right-handed) angular motion. The formed non-parallel plate capacitor structure in which the width of the inner and outer electrode gap changes linearly along the deflection direction and/or the inner and outer electrode gap width changes and/or the inner and outer electrode overlap area changes is equivalent to having the same inner and outer electrode overlap area as when it is static. The equivalent parallel-plate capacitance of each side capacitance corresponds to the change of the inner and outer electrode gap width of the equivalent parallel-plate capacitance corresponding to each side capacitance relative to its static state, which corresponds to the single-mass plane three-axis MEMS inertial sensor. At the same time, the sensitive in-plane horizontal forward (or backward) linear acceleration motion, the in-plane horizontal left (or right) linear acceleration motion, and the in-plane horizontal left-handed (or right-handed) angular motion make the external electrodes of the relevant side capacitances Relative to the offset and deflection simultaneously generated by the inner electrode, that is, the acceleration, the plane corresponding to the in-plane horizontal forward (or backward) linear acceleration motion simultaneously sensed by the single-mass plane three-axis MEMS inertial sensor. The acceleration of the in-plane horizontal leftward (or right) linear acceleration motion and the angular velocity of the in-plane horizontal left-handed (or right-handed) angular motion.

According to the principle of motion independence, the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to in-plane horizontal forward (or backward) linear acceleration motion, in-plane horizontal leftward (or right) linear acceleration motion, and in-plane horizontal acceleration motion. The left-handed (or right-handed) angular movement makes the variation of the inner and outer electrode gap width of the equivalent parallel plate capacitance corresponding to the relevant side capacitance relative to the variation of the inner and outer electrode gap width when it is static as the single-mass plane triaxial MEMS inertial sensor respectively The forward (or backward) linear acceleration motion in the sensitive plane, the left (or right) linear acceleration motion and the left-handed (or right-handed) angular motion in the plane make the inner and outer electrode gaps of the equivalent parallel plate capacitance corresponding to the relevant side capacitance The algebraic sum of the change in width relative to the width of the inner and outer electrode gaps when they are static.

And, based on the same mass and side capacitance structure, the single-mass planar three-axis MEMS inertial sensor is individually sensitive to in-plane horizontal forward (or backward) linear acceleration motion to make the first sensing capacitance pair (or the second sensing capacitance pair). The variation of the inner and outer electrode gap widths of the two side capacitors in the sensing capacitor pair) is in the same direction and the same magnitude, and the variation of the inner and outer electrode gap widths of the respective side capacitors in the first sensing capacitor pair and each side capacitor in the second sensing capacitor pair. The offsets of the external electrodes of the third sensing capacitor pair and the fourth sensing capacitor pair relative to their inner electrodes are in the same direction and the same magnitude, and the third sensing capacitor pair and the fourth sensing capacitor pair are in the same direction and the same magnitude. The offset of the outer electrode of each side capacitor in the capacitor pair relative to its inner electrode has the same magnitude as the offset of the outer electrode of each side capacitor in the first sensing capacitor pair and the second sensing capacitor pair relative to its inner electrode.

And based on the same mass and side capacitance structure, the single-mass planar three-axis MEMS inertial sensor is only sensitive to the horizontal left (or right) linear acceleration movement in the plane to make the third sensing capacitance pair (or the fourth sensing capacitance pair) The variation of the inner and outer electrode gap widths of the two side capacitors in the capacitor pair) is in the same direction and the same amplitude, and the variation of the inner and outer electrode gap widths of the respective side capacitors in the third sensing capacitor pair and the fourth sensing capacitor pair. The opposite is the same amplitude, the offset of the outer electrodes of each side capacitor in the first sensing capacitor pair and the second sensing capacitor pair relative to its inner electrodes are the same direction and the same amplitude, the first sensing capacitor pair and the second sensing capacitor The offset of the outer electrode of each side capacitor in the pair relative to its inner electrode has the same magnitude as the offset of the outer electrode of each side capacitor in the third sensing capacitor pair and the fourth sensing capacitor pair relative to its inner electrode.

Based on the same mass and side capacitance structure, the single-mass planar three-axis MEMS inertial sensor is individually sensitive to in-plane horizontal left-handed (or right-handed) angular movement, so that the width of the inner and outer electrode gaps of each side capacitance changes linearly along the deflection direction The amount of change is the same in the same direction and the same amplitude, and the changes of the overlapping areas of the inner and outer electrodes of each side capacitor along the front side of each sensing capacitor pair along the front side of the deflection direction are in the same direction and the same amplitude.

Correspondingly, the capacitance value of each side capacitor changes accordingly, and the change amount of the capacitance value of each side capacitor corresponds to the single-mass planar three-axis MEMS inertial sensor at the same time or respectively sensing the horizontal forward (or backward) straight line in the plane. Acceleration motion, in-plane horizontal left (or right) linear acceleration motion, and in-plane horizontal left-handed (or right-handed) angular motion make the inner and outer electrode gap width of the equivalent parallel plate capacitance corresponding to the relevant side capacitance relative to its static time The variation of the gap width between the inner and outer electrodes corresponds to the in-plane horizontal forward (or backward) linear acceleration motion, the in-plane horizontal left (or to the left) that the single-mass planar three-axis MEMS inertial sensor is simultaneously or respectively sensitive to. Right) Linear acceleration motion, in-plane horizontal left-handed (or right-handed) angular motion make the offset and/or deflection of the outer electrode of the relevant side capacitor relative to its inner electrode, that is, corresponding to the three-axis plane of the single-mass block The acceleration of in-plane horizontal forward (or backward) linear acceleration motion and/or the acceleration of in-plane horizontal leftward (or right) linear acceleration motion and/or the in-plane horizontal left-hand rotation ( or right-handed) angular velocity of angular motion.

To sum up, it can be concluded that when the single-mass planar three-axis MEMS inertial sensor is simultaneously or respectively sensitive to in-plane forward (or backward) linear acceleration, in-plane left (or right) linear acceleration, and in-plane left (or right) When rotating) angular motion, the change of the gap width of the inner and outer electrodes of the equivalent parallel plate capacitor corresponding to the plane inertial motion of each axis relative to the gap width of the inner and outer electrodes when it is static and the change of the capacitance value of each side capacitor Relationship.

Accordingly, the variation of the gap width of the inner and outer electrodes of the equivalent parallel plate capacitor corresponding to the plane inertial motion of each axis can be separated relative to the gap width of the inner and outer electrodes when it is static, and the single-mass plane can be separated. The three-axis MEMS inertial sensor is simultaneously sensitive to three of the in-plane horizontal forward (or backward) linear acceleration motion, the in-plane horizontal left (or right) linear acceleration motion, and the in-plane horizontal left-handed (or right-handed) angular motion The acceleration and angular velocity of the inertial motion in the axial plane realizes the decoupling between the three axial plane inertial motions.

Accordingly, by measuring the change in capacitance value of each side capacitance by the corresponding side capacitance output electrodes, it can be calculated that the in-plane horizontal forward (or backward) and in-plane horizontal sensitivity of the single-mass planar three-axis MEMS inertial sensor can be calculated at the same time. Acceleration and angular velocity for three axial in-plane inertial motions in left (or right) linear acceleration motion and in-plane horizontal left-handed (or right-handed) angular motion.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The single-mass plane three-axis MEMS inertial sensor of the present invention adopts the inertial mass-sensitive method to realize the MEMS inertial accelerometer and the MEMS inertial gyroscope, and simultaneously senses the acceleration of the horizontal linear motion in the plane and the horizontal rotation in the plane made by the moving object. The angular velocity of the movement, to realize the monitoring of the plane inertial motion state of the moving object;

When the planar three-axis inertial sensor is simultaneously or respectively sensitive to in-plane forward (or backward) linear acceleration motion, in-plane leftward (or right) linear acceleration motion, and in-plane left-handed (or right-handed) angular motion, the Due to the inertia of the mass relative to the cavity, the in-plane horizontal backward (or forward) offset, the in-plane horizontal rightward (or left) offset and the in-plane horizontal right-handed (or left-handed) deflection are generated simultaneously or respectively correspondingly. , the resulting offsets and deflections of each axial direction correspond to the acceleration and angular velocity of the sensitive plane triaxial inertial motion;

Compared with the conventional vibration sensitive method used in MEMS gyroscopes, the planar three-axis inertial sensor of the present invention has a simpler structure and simpler process preparation because no additional driving mechanism is required.

(2) The single-mass planar three-axis MEMS inertial sensor of the present invention adopts a single-mass structure, and the mass can be individually sensitive to in-plane horizontal linear motion or in-plane horizontal rotational angular motion, or simultaneously sensitive to in-plane horizontal linear motion and in-plane horizontal rotation angular motion;

Compared with a multi-axis inertial motion sensor with a multi-mass structure, the single-mass planar three-axis MEMS inertial sensor of the present invention only includes a set of mass-cantilever beam systems, and simultaneously realizes the functions of an accelerometer and a gyroscope, and the overall structure is simplified , the preparation process is simple.

(3) The single-mass plane three-axis MEMS inertial sensor of the present invention utilizes the planar electrode pairs fabricated on the outer side of the mass block and the inner side of the cavity to form a parallel plate capacitance, and senses the acceleration of horizontal linear motion in the plane and the horizontal rotation in the plane angular velocity of movement;

Compared with the conventional comb-tooth capacitance sensitive structure, the sensing capacitor in the present invention has a large electrode area, a large dynamic range of the sensing capacitance value, high sensing accuracy, simplified overall structure and simple preparation process.

(4) The single-mass plane three-axis MEMS inertial sensor of the present invention adopts the equivalent capacitance method to extract the corresponding relationship between the acceleration and angular velocity of each axial inertial motion and the capacitance value change of the relevant bottom capacitance according to the principle of motion independence , separates the linear acceleration motion and the rotational angular motion of each axis, realizes the decoupling between each axial motion amount of the sensed planar three-axis inertial motion, and improves the sensing sensitivity and sensing accuracy of each axial motion amount.

(5) The single-mass planar three-axis MEMS inertial sensor of the present invention adopts a symmetrically arranged combined S-shaped cantilever beam structure. When the mass supported by the cantilever beam is sensitive to inertial motion, it is easy to generate in-plane radial offset, lateral Offset and rotational offset are not easy to generate out-of-plane vertical offset and vertical rotation, that is, the single-mass planar three-axis MEMS inertial sensor structure is only sensitive to in-plane horizontal linear acceleration motion and in-plane rotational angular motion, while out-of-plane vertical motion is sensitive. The linear acceleration motion and the out-of-plane vertical rotational angular motion are insensitive, which can realize the decoupling of the in-plane three-axis inertial motion and the unexpected out-of-plane inertial motion that the single-mass planar three-axis MEMS inertial sensor is sensitive to. Sensing sensitivity and sensing accuracy of inertial mass. The present invention can be used to sense planar three-axis including in-plane horizontal forward (or backward) linear acceleration motion, in-plane horizontal leftward (or right) linear acceleration motion and in-plane horizontal left-handed (or right-handed) angular motion inertial motion.

Description of drawings

1 is a cross-sectional view of the overall structure of the present invention;

2 is a schematic diagram of the structure of the bottom electrode of the bottom plate in the present invention;

3 is a schematic diagram of the structure of the top electrode of the bottom plate in the present invention;

4 is a schematic diagram of the bottom surface of the cavity structure layer in the present invention;

5 is a schematic diagram of the bottom surface of the mass block and the cantilever beam structure layer in the present invention;

6 is a schematic diagram of the top surface of the mass block and the cantilever beam structure layer in the present invention;

7 is a schematic diagram of the bottom surface of the top plate in the present invention;

8 is a schematic diagram of the structure of the top electrode of the top plate in the present invention;

9 is a schematic diagram of a side capacitance structure and distribution in the present invention;

In the figure: 1 base plate, 11 base plate substrate, 12 side capacitor output electrode, 13 side capacitor outer electrode lower lead-out electrode, 14 base plate bonding ring, 15 base plate metal through hole;

2 cavity structure layer, 21 cavity substrate, 22 cavity, 23 side capacitor outer electrode, 24 side capacitor outer electrode lead-out electrode, 25 cavity substrate bottom bonding ring, 26 cavity substrate top bonding ring;

3-mass and cantilever beam structure layer, 31-mass, 32-side capacitor inner electrode, 33-side capacitor inner electrode lead-out electrode, 34-mass metal through hole, 35S-shaped cantilever beam, 351S-shaped cantilever beam radial arm, 352S-shaped cantilever Beam transverse arm, 353 inner radial support arm, 354 outer radial support arm, 36 cantilever beam fixing frame, 37 ground electrode;

4 top plate, 41 top plate base plate, 42 top plate cavity, 43 grounding lead-out electrodes, 44 grounding output electrodes, 45 top plate metal through holes;

5 insulating layers;

6-side capacitor, 61-side capacitor C1, 62-side capacitor C2, 63-side capacitor C3, 64-side capacitor C4, 65-side capacitor C5, 66-side capacitor C6, 67-side capacitor C7, and 68-side capacitor C8.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

1 to 8, the single-mass planar three-axis MEMS inertial sensor includes a bottom plate 1, a cavity structure layer 2, a mass block and cantilever beam structure layer 3, and a top plate 4. The above-mentioned structural layers are sequentially keyed from bottom to top combine.

1, 2 and 3, the base plate 1 includes a base plate substrate 11, 4 sets of side capacitor output electrodes 12, 4 sets of side capacitor external electrodes lower lead-out electrodes 13, a base plate bonding ring 14 and 8 base metal through holes 15.

The base substrate 11 is a substrate with a square cross-section;

The four groups of side capacitor output electrodes are located on the four sides of the bottom surface of the base substrate and are symmetrically distributed with respect to the center of the bottom surface of the base substrate. One group of side capacitor output electrodes includes two parallel side capacitor output electrodes 12, and each side capacitor output electrode is the same rectangular electrode. ;

The 4 groups of side capacitor outer electrodes lower lead-out electrodes are located on the top surface of the base plate substrate and are symmetrically distributed with respect to the center of the top surface of the bottom plate substrate. The lead-out electrodes under the outer electrodes of each side capacitor are rectangular electrodes of the same shape;

Each side capacitor output electrode (12) is directly opposite to the lower lead-out electrode (13) of one side capacitor outer electrode;

The eight bottom metal through holes 15 penetrate through the bottom plate substrate, and one bottom metal through hole is correspondingly connected to one side capacitor output electrode and one side capacitor outer electrode lower lead-out electrode;

The bottom plate bonding ring 14 is a rectangular ring with an inner side and an outer side, which is located on the four sides of the top surface of the bottom plate substrate and surrounds the four sets of side capacitor outer electrode lower lead-out electrodes.

1 and 4, the cavity structure layer 2 includes a cavity substrate 21, a cavity 22, 4 groups of side capacitor external electrodes 23, 4 groups of side capacitor external electrodes on the lead-out electrodes 24, and a bonding ring on the bottom surface of the cavity substrate 25 and the bonding ring 26 on the top surface of the cavity substrate;

The cavity substrate 21 is a thick substrate with a square outer edge;

The cavity 22 is a regular octagonal prism, located in the middle of the cavity substrate and passing through the cavity substrate;

The 4 groups of side capacitor outer electrodes are arranged alternately on the four inner surfaces of the cavity, front, back, left, right, and right. One group of side capacitor outer electrodes includes two side capacitor outer electrodes 23 in parallel. Each side capacitor outer electrode is a rectangular electrode of the same shape. The height of the capacitor outer electrodes is the same as the height of the cavity, and the total width of the 2 side capacitor outer electrodes and their gaps in each group of side capacitor outer electrodes is the same as the side of the mass block and the regular octagonal prism-shaped mass block in the cantilever beam structure layer. The width of the electrodes in the capacitor is the same;

The lead-out electrodes on the 4 groups of side capacitor outer electrodes are located on the bottom surface of the cavity substrate and face the 4 groups of side-capacitance outer electrodes respectively. The lead-out electrodes on the outer electrodes of each side capacitor are rectangular electrodes of the same shape, and the inner ends of the lead-out electrodes on the outer electrodes of each side capacitor are connected with the lower ends of the corresponding side-capacitor outer electrodes;

The bonding ring 25 on the bottom surface of the cavity substrate is a rectangular ring with an inner side and an outer side. The bonding ring on the bottom surface of the cavity substrate is located on the four sides of the bottom surface of the cavity substrate and surrounds the four sets of side capacitor external electrodes.

The bonding ring 26 on the top surface of the cavity substrate is a rectangular ring with an inner side and an outer side, and the bonding ring on the top surface of the cavity substrate surrounds the four sides of the top surface of the cavity substrate.

1, 5 and 6, the mass block and cantilever beam structure layer 3 includes a regular octagonal mass block 31, four side capacitor inner electrodes 32, side capacitor inner electrode lead-out electrodes 33, and a metal through hole of the mass block. 34. Four S-shaped cantilever beams 35, cantilever beam fixing frame 36 and ground electrode 37;

The mass block 31 is a regular octagonal prism corresponding to the cavity;

The four side capacitor inner electrodes 32 are alternately arranged on the front, rear, left and right outer sides of the mass block, and the upper end of each side capacitor inner electrode (32) is flush with the lower surface of each S-shaped cantilever beam (35);

The side capacitor inner electrode lead-out electrode 33 covers the bottom surface of the mass block, and the outer edge of the side capacitor inner electrode lead-out electrode is connected to the lower end of each side capacitor inner electrode;

The mass metal through hole 34 runs through the center of the mass block, and the mass metal through hole is connected to the lead-out electrode of the side capacitor inner electrode on the bottom surface of the mass block and the ground electrode on the top surface of the mass block;

The one S-shaped cantilever beam includes several radial arms 351 and several transverse arms 352, and one inner radial support arm 353 and one outer radial support arm 354, each radial arm and each transverse arm have the same length and the same width, the length of each radial arm and each transverse arm is at least 4 times its width, the each inboard radial support arm and each outboard radial support arm have the same length and the same The width of each inner radial support arm and each outer radial support arm is not greater than its width, and the width of each inner radial support arm and each outer radial support arm is not less than 1 of the length of the transverse arm /2, each radial arm, transverse arm, inner radial support arm, and outer radial support arm have the same thickness, and each radial arm, transverse arm, inner radial support arm, and outer radial support arm is at least twice the width of the radial or transverse arms;

The inner radial support arm, a plurality of transverse arms, a plurality of radial arms, and outer radial support arms in each of the S-shaped cantilever beams are connected orthogonally in sequence, wherein each transverse arm and each radial arm are orthogonally connected to each other in turn. , each S-shaped cantilever beam is alternately connected to the center of the top of the front, rear, left, right and left sides of the mass block through the inner end of its inner radial support arm, and each S-shaped cantilever beam is alternately connected to the cantilever beam through the outer end of its outer radial support arm In the middle of the inner tops of the four sides of the front, rear, left and right sides of the fixed frame, the top surface of each S-shaped cantilever beam is flush with the top surface of the mass block and the top surface of the fixed frame of the cantilever beam.

The cantilever beam fixing frame 36 is a hollow frame with a square section inside and outside;

The ground electrode 37 covers the top surface of the mass block, the top surface of each cantilever beam and the top surface of the cantilever beam fixing frame.

1, 7 and 8, the top plate 4 includes a top plate substrate 41, a top plate cavity 42, a ground lead-out electrode 43, four ground output electrodes 44 and four top plate metal through holes 45;

The top plate substrate 41 is a substrate with a square cross-section;

The top plate cavity 42 is located in the middle of the bottom surface of the top plate substrate, the cross section of the top plate cavity is identical to the cross section of the hollow part of the cantilever beam fixing frame, and the depth of the top plate cavity is half of the thickness of the top plate substrate;

The grounding lead-out electrodes 43 cover the four sides of the bottom surface of the top plate substrate;

The four grounding output electrodes 44 are located on the top surface of the top plate substrate and are symmetrically distributed with respect to the center thereof;

The four top plate metal through holes 45 penetrate through the top plate substrate, and the four top plate metal through holes correspond to connect the four ground output electrodes on the top surface of the top plate substrate and the ground lead-out electrodes on the bottom surface of the top plate substrate.

Referring to FIG. 1 , the bottom plate substrate, the cavity substrate, the cantilever beam fixing frame and the top plate substrate have square outer edges with the same side length;

Referring to FIG. 1 , the bottom surface of the bottom plate, the bottom surface of the cavity substrate, the top surface of the cavity substrate, the bottom surface of the cantilever beam fixing frame, the top surface of the cantilever beam fixing frame and the grounding lead of the bottom surface of the top plate substrate. The electrodes are all identical;

With reference to FIG. 1 , each electrode, each bonding ring and the substrate where it is located, and each metal through hole and the substrate penetrated therethrough are electrically isolated by an insulating layer 5 ;

The substrate materials of the top plate 1, the cavity structure layer 2 and the bottom plate 4 are all silicon single crystals, and the substrates for making the mass block and the cantilever beam structure layer 3 are SOI substrates. The material of the hole is gold, and the material of the insulating layer 5 is silicon dioxide or silicon nitride;

Referring to FIG. 1 , the bottom surface bonding ring 25 of the cavity substrate on the bottom surface of the cavity structure layer 2 is gold-gold bonded to the bottom surface bonding ring 15 on the top surface of the bottom plate 1 , and the bottom surface of the cantilever beam fixing frame 36 is connected to the cavity structure layer. 2. The top surface bonding ring 26 of the top surface of the cavity substrate is gold-silicon bonded, each cantilever beam is suspended above the cavity 21 and the mass 31 is suspended in the cavity 21, and the grounding electrodes 43 on the four sides of the bottom surface of the top plate 4 are suspended It is gold-gold bonded with the ground electrode 44 on the top surface of the cantilever beam fixing frame 36 to finally form a hermetically sealed structure.

1 and 9, in the single-mass planar three-axis MEMS inertial sensor structure, 4 side capacitance inner electrodes on the outer side of the mass block and 4 groups of side capacitance outer electrodes corresponding to the inner side of the cavity constitute 8 Side capacitors C1, C2, C3, C4, C5, C6, C7 and C8.

Among the eight side capacitors, C1 and C2 form a first sensing capacitor pair, C3 and C4 form a second sensing capacitor pair; C5 and C6 form a third sensing capacitor pair, and C7 and C8 form a fourth sensing capacitor right;

1 and 9, in static state, the bottom surface of the mass suspended in the cavity and the top surface of the bottom plate and the top surface of the mass block and the top surface of the top plate cavity maintain the initial distance, and the eight outer sides of the mass block are respectively Parallel to, facing and equidistant from the 8 inner sides of the cavity, the 4 side capacitor inner electrodes on the outer side of the mass block and the corresponding 4 groups of side capacitor outer electrodes are parallel, facing and keep the same gap width d ₀ , C1, C2, C3, C4, C5, C6, C7, and C8 have the same static capacitance value C0, and C1, C2, C3, C4, C5, C6, C7, and C8 are connected to each ground output electrode by The formed 8 side capacitance output ports output the same static capacitance value signal.

1 and 9, when the single-mass planar three-axis MEMS inertial sensor is only sensitive to in-plane horizontal forward (or backward) linear acceleration movement, the mass due to inertia produces an in-plane horizontal backward relative to the cavity. Offset (or forward), the outer electrodes of the first sensing capacitor pair C1 and C2 are horizontally shifted away (or close) in-plane relative to their inner electrodes, while the outer electrodes of the second sensing capacitor pair C3 and C4 Relative to the in-plane horizontal approach (or distance) offset of the inner electrodes, the overlapping area of the inner and outer electrodes of C1, C2, C3 and C4 remains unchanged, while the width of the inner and outer electrodes of C1 and C2 increases (or decreases) , the inner and outer electrode gap widths of C3 and C4 decrease (or increase), the capacitance values of C1 and C2 decrease (or increase), the capacitance values of C3 and C4 increase (or decrease), and C1 The capacitance value change of C2, C3 and C4 corresponds to the change of the width of the inner and outer electrode gaps, that is, corresponding to the in-plane horizontal forward (or backward) linear acceleration motion of the single-mass planar three-axis MEMS inertial sensor. acceleration.

Based on the same mass block and side capacitance structure, the changes of the inner and outer electrode gap widths of C1 and C2, and C3 and C4 are opposite to the same magnitude. Let the variation of the inner and outer electrode gap widths of C1 and C2 and C3 and C4 be Δd, then The inner and outer electrode gap widths of C1 and C2 increase from d ₀ to d ₀ +Δd (or decrease to d ₀ -Δd), while the inner and outer electrode gap widths of C3 and C4 decrease from d ₀ to d ₀ - △d (or increased to d ₀ +△d), the capacitance values of C1, C2, C3 and C4 are correspondingly changed from their static capacitance values CO to:

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In the formula, d ₀ is the initial gap width of the inner and outer electrodes of each side capacitor, S ₀ is the overlapping area of the inner and outer electrodes of each side capacitor, and ε is the dielectric constant of the inner and outer electrode gap medium of each side capacitor.

Accordingly, the in-plane horizontal direction sensed by the single-mass planar triaxial MEMS inertial sensor can be calculated by measuring the capacitance value changes of C1, C2, C3 and C4 through the side capacitance output electrodes of C1, C2, C3 and C4. The acceleration of the forward (or backward) linear acceleration motion.

1 and 9, when the single-mass planar three-axis MEMS inertial sensor is only sensitive to the in-plane horizontal acceleration to the left (or right), the mass is caused by inertia relative to the cavity to generate the in-plane horizontal to the right. Offset (or to the left), the inner electrodes of the third sensing capacitor pair C5 and C6 are horizontally shifted away (or close) in-plane relative to their outer electrodes, while the inner electrodes of the fourth sensing capacitor pair C7 and C8 Relative to the in-plane horizontal approach (or distance) offset of the external electrodes, the overlapping area of the internal and external electrodes of C5, C6, C7 and C8 remains unchanged, while the width of the gap between the internal and external electrodes of C5 and C6 increases (or decreases). , the inner and outer electrode gap widths of C7 and C8 decrease (or increase), the capacitance values of C5 and C6 decrease (or increase), the capacitance values of C7 and C8 increase (or decrease), and C5 The capacitance value change of C6, C7 and C8 corresponds to the change in the width of the inner and outer electrode gaps, that is, the in-plane horizontal left (or right) linear acceleration sensed by the single-mass planar three-axis MEMS inertial sensor acceleration of movement.

Based on the same mass block and side capacitance structure, the changes of the inner and outer electrode gap widths of C5 and C6 and C7 and C8 are opposite to the same magnitude. If the variation of the inner and outer electrode gap widths of C5 and C6 and C7 and C8 is Δd, then The inner and outer electrode gap widths of C5 and C6 increase from d ₀ to d ₀ +Δd (or decrease to d ₀ -Δd), while the inner and outer electrode gap widths of C7 and C8 decrease from d ₀ to d ₀ - △d (or increased to d ₀ +△d), the capacitance values of C5, C6, C7 and C8 are correspondingly changed from their static capacitance values CO to:

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In the formula, d ₀ is the initial gap width of the inner and outer electrodes of each side capacitor, S ₀ is the initial overlap area of the inner and outer electrodes of each side capacitor, and ε is the dielectric constant of the inner and outer electrode gap medium of each side capacitor.

Accordingly, the in-plane horizontal direction sensed by the single-mass planar three-axis MEMS inertial sensor can be calculated by measuring the capacitance value changes of C5, C6, C7 and C8 through the side capacitance output electrodes of C5, C6, C7 and C8. The acceleration of the left (or right) linear acceleration movement.

1 and 9, when the single-mass planar three-axis MEMS inertial sensor is only sensitive to in-plane horizontal left-handed (or right-handed) angular motion, the mass produces an in-plane horizontal right-handed (or right-handed) relative to the cavity due to inertia. Left-handed) deflection, based on the same side capacitor structure, the inner electrodes of C1, C2, C3, C4, C5, C6, C7 and C8 are simultaneously in-plane horizontal left-hand rotation in the same direction and amplitude with respect to the outer electrodes of the side capacitors (or right-handed) deflection, where:

The outer electrodes of C1, C4, C5, and C8 (or C2, C3, C6, and C7) move out and deflect horizontally in the plane relative to their inner electrodes. C1, C4, C5, and C8 (or C2, C3) , C6 and C7), the overlapping area of the inner and outer electrodes decreases and the width of the inner and outer electrodes decreases linearly along the deflection direction;

The external electrodes of C2, C3, C6, and C7 (or C1, C4, C5, and C8) are in-plane horizontal left-handed (or right-handed) in-plane deflections relative to their internal electrodes, and C2, C3, C6, and C7 (or C1, C4) , C5 and C8), the overlapping area of the inner and outer electrodes is constant, but the width of the inner and outer electrodes decreases linearly along the deflection direction;

Only the cases of C2, C3, C6 and C7 (or C1, C4, C5 and C8) are considered.

As mentioned above, when the single-mass planar three-axis MEMS inertial sensor is only sensitive to in-plane horizontal left-handed (or right-handed) angular motion, the inside and outside of C2, C3, C6 and C7 (or C1, C4, C5 and C8) The overlapping area of the electrodes remains unchanged, but the width of the inner and outer electrode gaps decreases linearly along the deflection direction. Non-parallel plate capacitor structure with linearly decreasing deflection direction;

The capacitance values of C2, C3, C6, and C7 (or C1, C4, C5, and C8) change accordingly, and the change in the capacitance values of C2, C3, C6, and C7 (or C1, C4, C5, and C8) corresponds to The relative inclination angle between the inner and outer electrodes corresponds to the linear change rate of the gap width between the inner and outer electrodes along the deflection direction, that is, corresponds to the in-plane horizontal left rotation (or right rotation) sensed by the single-mass planar three-axis MEMS inertial sensor. Rotation) Angular velocity of angular motion.

The C2, C3, C6 and C7 (or C1, C4, C5 and C8) of the non-parallel plate structure are equivalent to the equivalent parallel plate capacitances with the same inner and outer plate overlapping areas when they are static, and based on For the same mass block and side capacitor structure, the relative inclination angles between the inner and outer electrodes of C2, C3, C6 and C7 (or C1, C4, C5 and C8) are in the same direction and the same size, set C2, C3, C6 and C7 (or C1 , C4, C5 and C8) corresponding to the equivalent parallel-plate capacitors, the variation of the inner and outer electrode gap widths relative to its static inner and outer electrode gap widths is Δd, then the gap width of each equivalent parallel-plate capacitor is d ₀ +Δd (or d ₀ -Δd), the capacitance values of C1, C4, C5 and C8 (or C2, C3, C6 and C7) are correspondingly changed from their static capacitance values CO as:

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In the formula, φ is the left-handed (or right-handed) deflection angle of the inner electrodes of C1, C4, C5, and C8 (or C2, C3, C6, and C7) relative to their outer electrodes, that is, the single-mass plane triaxial inertial sensor The angular displacement of the sensitive in-plane horizontal left-handed (or right-handed) angular movement, a is the width of the outer electrodes of each side capacitor, d ₀ is the initial gap width of the inner and outer electrodes of each side capacitor, S ₀ is the inner and outer electrodes of each side capacitor The initial overlap area, ε is the dielectric constant of the inner and outer electrode gap medium of each side capacitor.

Accordingly, the capacitance value change of C1, C4, C5 and C8 (or C2, C3, C6 and C7) is measured through the side capacitance output electrodes of C1, C4, C5 and C8 (or C2, C3, C6 and C7), The angular velocity of the in-plane horizontal left-handed (or right-handed) angular motion sensed by the single-mass plane three-axis inertial sensor can be calculated.

With reference to Figure 1 and Figure 9, when the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to in-plane horizontal linear acceleration motion and in-plane horizontal angular motion, the mass of the mass produces an in-plane horizontal offset relative to the cavity at the same time due to inertia. and in-plane horizontal deflection, the outer electrodes of C1, C2, C3, C4, C5, C6, C7 and C8 perform in-plane horizontal offset and in-plane horizontal deflection simultaneously with respect to their inner electrodes, C1, C2, C3, C4, The overlapping area and gap width of the inner and outer electrodes of C5, C6, C7 and C8 change correspondingly at the same time, and the capacitance values of C1, C2, C3, C4, C5, C6, C7 and C8 change accordingly.

Without loss of generality, the case where the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to in-plane horizontal forward linear acceleration motion, in-plane horizontal leftward linear acceleration motion, and in-plane horizontal left-handed angular motion is described as an example as follows. :

The combined action of the above three inertial motions causes the mass to simultaneously generate in-plane horizontal backward offset, in-plane horizontal rightward offset and in-plane horizontal right-rotation deflection relative to the cavity, C1, C2, C3, C4, C5, The outer electrodes of C6, C7, and C8 simultaneously perform corresponding in-plane horizontal offsets and in-plane horizontal deflections relative to their inner electrodes, where:

Relative to its inner electrode, the external electrode of C1 simultaneously performs the in-plane horizontal forward shift away, the in-plane horizontal shift to the left, and the in-plane horizontal left-hand out deflection;

The external electrode of C2 performs in-plane horizontal forward shift, in-plane horizontal left-in shift and in-plane horizontal left-hand-in deflection simultaneously with respect to its inner electrode;

The external electrode of C3 performs in-plane horizontal forward approaching offset, in-plane horizontal left-out offset and in-plane horizontal left-handed in-deflection with respect to its internal electrode at the same time;

The external electrode of C4 simultaneously deflects the in-plane horizontal forward approach, the in-plane horizontal leftward shift and the in-plane horizontal left-handed out deflection relative to its inner electrode;

The external electrode of C5 simultaneously deflects the in-plane horizontal to the left, the in-plane horizontal moves forward, and the in-plane horizontal left-handed out deflection relative to its internal electrode;

The outer electrode of C6 simultaneously deflects the in-plane horizontal to the left, the in-plane horizontal forward offset and the in-plane horizontal left-hand inward deflection relative to the inner electrode;

The external electrode of C7 is simultaneously deflected to the left in the in-plane horizontal direction, the in-plane horizontal moves forward in the offset, and the in-plane horizontal left-handed out deflection with respect to the internal electrode;

The outer electrode of C8 is simultaneously deflected to the left of the in-plane horizontal, the in-plane horizontal out-shift and the in-plane horizontal left-handed in-deflection relative to its inner electrode.

For the convenience of analysis, only C2, C3, C6 and C7, which are the same in-plane horizontal left-handed shift-in deflection, are discussed as follows:

According to the principle of motion independence, the in-plane horizontal forward linear acceleration motion, the in-plane horizontal leftward linear acceleration motion and the in-plane horizontal left-handed angular motion that the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to make C2, C3, The external electrodes of C6 and C7 simultaneously perform in-plane horizontal forward displacement, in-plane horizontal leftward displacement, and in-plane horizontal left-handed deflection relative to their internal electrodes, which can be regarded as the above-mentioned three plane inertial motions that are respectively sensitive to C2, C3 , the superposition of the in-plane horizontal forward offset, the in-plane horizontal leftward offset and the in-plane horizontal left-handed deflection of the external electrodes of C6 and C7 relative to their internal electrodes, respectively, where:

When the single-mass planar three-axis MEMS inertial sensor moves linearly forward in a single sensitive plane horizontally, the outer electrode of C2 only moves away from the plane horizontally with respect to its inner electrode, and the width of the gap between the inner and outer electrodes of C2 increase and the overlapping area of its inner and outer electrodes remains unchanged, while the outer electrode of C3 only makes an in-plane horizontal offset forward relative to its inner electrode, and the width of the gap between the inner and outer electrodes of C3 decreases while the overlapping area of its inner and outer electrodes remains Invariant, based on the same mass and side capacitance structure, the variation of the inner and outer electrode gap widths of C2 and C3 is opposite to the same magnitude, and the variation of the inner and outer electrode gap width is set to be Δdx, which corresponds to the plane of the single mass block The acceleration of the in-plane horizontal forward linear acceleration sensed by the three-axis MEMS inertial sensor;

Based on the same-side capacitance structure, when the single-mass planar three-axis MEMS inertial sensor moves horizontally and linearly forward in the sensitive plane, the outer electrode of C6 moves forward horizontally in the plane relative to its inner electrode, and the C6 The overlapping area of the inner and outer electrodes decreases while the width of the gap between the inner and outer electrodes remains unchanged, and the displacement of the outer electrode of C6 relative to the in-plane horizontal forward offset of its inner electrode is the same as that of the outer electrodes of C2 and C3 relative to its inner electrode. The in-plane horizontal displacement of the electrodes is the same, and C6 is equivalent to the equivalent parallel plate capacitance with the same overlapping area of the inner and outer electrodes as it is static, and the equivalent parallel electrode corresponding to C6 is set. The change of the gap width of the inner and outer electrodes of the plate capacitor relative to the gap width d _O of the inner and outer electrodes when it is static is Δdy', then:

In the formula, d ₀ is the initial gap width of the inner and outer electrodes of each side capacitor, and a is the outer electrode width of each side capacitor.

When the single-mass planar three-axis MEMS inertial sensor moves in a single sensitive plane with horizontal acceleration to the left in a straight line, the outer electrode of C6 only moves away from the plane horizontally to the left relative to its inner electrode, and the width of the gap between the inner and outer electrodes of C6 increase and the overlapping area of its inner and outer electrodes remains unchanged, while the outer electrode of C7 only moves to the left in the in-plane horizontal relative to its inner electrode, and the width of the gap between the inner and outer electrodes of C7 decreases while the overlapping area of its inner and outer electrodes remains Invariant, based on the same mass and side capacitance structure, the variation of the inner and outer electrode gap widths of C6 and C7 is opposite to the same magnitude, and the variation of the inner and outer electrode gap width is set as Δdy, which corresponds to the plane of the single mass block The acceleration of the horizontal leftward linear acceleration in the plane sensed by the three-axis MEMS inertial sensor;

Based on the same-side capacitance structure, when the single-mass planar three-axis MEMS inertial sensor accelerates horizontally to the left in the sensitive plane, the outer electrode of C3 moves out of the plane horizontally to the left relative to its inner electrode, and C3 The overlapping area of the inner and outer electrodes decreases while the width of the gap between the inner and outer electrodes remains unchanged, and the displacement of the outer electrode of C3 relative to the in-plane level of the inner electrode to the left is the same as that of the outer electrodes of C6 and C7 relative to the inner electrode. The displacement of the electrode in-plane horizontally away from (or close to) the left is equal, and C3 is equivalent to the equivalent parallel plate capacitance with the same overlapping area of the inner and outer plates as it is static, and the equivalent parallel plate corresponding to C3 is set. The change of the inner and outer electrode gap width of the plate capacitor relative to the inner and outer electrode gap width d _O when it is static is Δdx', then:

In the formula, d ₀ is the initial gap width of the inner and outer electrodes of each side capacitor, and a is the outer electrode width of each side capacitor.

When the single-mass plane triaxial inertial sensing structure is only sensitive to in-plane horizontal left-handed angular motion, the outer electrodes of C2, C3, C6 and C7 only perform in-plane horizontal left-handed movement in deflection relative to their inner electrodes, C2, C3 , C6 and C7 have a linear decrease in the width of the inner and outer electrode gaps along the deflection direction while the overlapping area of the inner and outer electrodes remains unchanged. The non-parallel plate capacitor structure in which the deflection direction decreases linearly and the overlapping area of the inner and outer electrodes remains unchanged. The C2, C3, C6 and C7 of this non-parallel plate structure are equivalent to having the same overlapping area of the inner and outer plates as in the static state. , and based on the same mass block and side capacitance structure, the linear change rates of the inner and outer electrode gap widths of C2, C3, C6 and C7 along the deflection direction are in the same direction and the same amplitude, that is, the equivalent parallel plate capacitance of The variation of the gap width of the inner and outer electrodes relative to the width d _O of the inner and outer electrode gaps in the static state is in the same direction and the same amplitude, and the width of the inner and outer electrode gaps of the equivalent parallel plate capacitors corresponding to C2, C3, C6 and C7 is set relative to its static state. The variation of the electrode gap width d _O is Δdz, which corresponds to the angular velocity of the in-plane horizontal left-handed angular motion sensed by the single-mass planar three-axis MEMS inertial sensor;

However, when the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to in-plane horizontal forward linear acceleration motion, in-plane horizontal leftward linear acceleration motion and in-plane horizontal left-handed angular motion, the outer surfaces of C2, C3, C6 and C7 are With respect to the inner electrode, the electrode simultaneously performs in-plane horizontal forward shift, in-plane horizontal leftward shift, and in-plane horizontal left-rotation deflection. The gap width changes and the gap width of the inner and outer electrodes changes linearly along the deflection direction. C2, C3, C6 and C7 are changed from the parallel plate capacitance structure of the inner and outer electrodes parallel to each other to their overlapping areas, and their inner and outer electrodes are inclined to each other and For the non-parallel plate capacitor structure with a linear change in the gap width, C2, C3, C6 and C7 of this non-parallel plate structure are respectively equivalent to the equivalent parallel plate capacitors with the same overlapping area of the inner and outer plates as they are statically, Let the variation of the gap width of the inner and outer electrodes of the equivalent parallel plate capacitors corresponding to C2, C3, C6 and C7 relative to the gap width d _O of the inner and outer electrodes when they are static are △d2, △d3, △d6 and △d7 respectively;

Then according to the principle of motion independence, Δd2, Δd3, Δd6 and Δd7 are the in-plane horizontal forward linear acceleration motion that the single-mass planar three-axis MEMS inertial sensor is sensitive to, making the gap between the inner and outer electrodes of C2 and C3. The variation of the width relative to the inner and outer electrode gap width d _O in static state Δdx or the variation of the inner and outer electrode gap width d O of the equivalent parallel plate capacitors corresponding to C6 and C7 relative to the variation Δdy' of the inner and outer electrode gap width d _O in static state, The in-plane horizontal and leftward linear acceleration motion to which the single-mass plane three-axis MEMS inertial sensor is sensitive makes the change _Δdy or C2, The variation Δdx' of the inner and outer electrode gap width of the equivalent parallel plate capacitance corresponding to C3 relative to the inner and outer electrode gap width d _O in static state, the in-plane horizontal left-handed angular motion to which the single-mass planar three-axis MEMS inertial sensor is sensitive Let the algebraic sum of the variation Δdz of the inner and outer electrode gap widths of the equivalent parallel plate capacitors of C2, C3, C6 and C7 relative to the variation of the inner and outer electrode gap width d _O when they are static, that is:

Δd ₂ =Δdx+0+Δdz, where

Δd ₃ =-Δdx+Δdx'+Δdz, where

Δd ₆ =Δdy'+Δdy+Δdz, where

Δd ₇ =0-Δdy+Δdz, where

and have:

And a:

In the formula, φ is the left-handed deflection angle of the outer electrodes of C2, C3, C6 and C7 relative to their inner electrodes, that is, the angular displacement of the in-plane horizontal left-handed angular motion to which the single-mass planar triaxial inertial sensor is sensitive, d ₀ is the initial gap width of the inner and outer electrodes of each side capacitor, S ₀ is the initial overlap area of the inner and outer electrodes of each side capacitor, a is the outer electrode width of each side capacitor, ε is the dielectric constant of the inner and outer electrode gap medium of each side capacitor .

To sum up, the relationship between Δdx, Δdy, Δdz and φ and C2, C3, C6 and C7 and C _O can be obtained, and the in-plane horizontal forward line corresponding to the single-mass planar three-axis MEMS inertial sensor to which the inertial sensor is sensitive can be obtained. The amount of in-plane horizontal deflection and the deflection of in-plane horizontal deflection generated between the inner and outer electrodes of C2, C3, C6 and C7 caused by acceleration motion, in-plane horizontal leftward linear acceleration motion and in-plane horizontal left-handed angular motion The relationship with C2, C3, C6, C7 and CO, the single-mass planar three-axis MEMS inertial sensor can be simultaneously sensitive to the in-plane horizontal forward linear acceleration motion, the in-plane horizontal leftward linear acceleration motion and the surface Accelerations and angular velocities of three plane inertial motions in inner horizontal right-handed angular motion versus C2, C3, C6 and C7 and CO.

According to this, the capacitance value changes of C2, C3, C6 and C7 are measured by the side capacitance output electrodes of C2, C3, C6 and C7, and the inner horizontal direction to which the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive can be calculated. The acceleration and angular velocity of the three plane inertial motions in the front linear acceleration motion, the in-plane horizontal leftward linear acceleration motion and the in-plane horizontal right-handed angular motion.

In the same way, for the combination of in-plane horizontal linear acceleration motion and in-plane horizontal rotational angular motion that are simultaneously sensitive to the single-mass planar three-axis MEMS inertial sensor, the relevant side capacitance similar to the above analysis can be obtained. The relationship between the in-plane horizontal offset between the inner and outer electrodes, the in-plane horizontal deflection and the capacitance value change of each side capacitance can be obtained. The relationship between the acceleration and angular velocity of the three plane inertial motions and the capacitance value change of the relevant side capacitance when any combination of the horizontal linear acceleration motion and the in-plane horizontal rotational angular motion is combined.

Accordingly, the capacitance value change of each side capacitance is measured by the side capacitance output electrode of the relevant side capacitance, and the in-plane horizontal linear acceleration motion and in-plane horizontal rotation that the single-mass planar three-axis MEMS inertial sensor is simultaneously sensitive to can be calculated. The accelerations and angular velocities of the three plane inertial motions for any combination of angular motions.

Based on the above analysis, by comparing the measured capacitance values of each side capacitance, the motion type and direction of the plane inertial motion sensed by the single-mass plane three-axis MEMS inertial sensor of the present invention can be qualitatively determined. The specific method is as follows:

When the single-mass plane three-axis MEMS inertial sensor is only used to sense the plane inertial motion of a single axis,

(1) If C1=C2>C3=C4, the sensed plane inertial motion is the horizontal forward linear acceleration motion in the plane;

(2) If C1=C2<C3=C4, the sensed plane inertial motion is the horizontal and backward linear acceleration motion in the plane;

(3) If C5=C6>C7=C8, the sensed plane inertial motion is the in-plane horizontal leftward linear acceleration motion;

(4) If C5=C6<C7=C8, the sensed plane inertial motion is the horizontal acceleration motion in the plane to the right;

(5) If C1=C5=C4=C8<C2=C6=C3=C7, the sensed plane inertial motion is the horizontal left-handed angle motion in the plane;

(6) If C1=C5=C4=C8>C2=C6=C3=C7, the sensed plane inertial motion is the in-plane horizontal right-handed angular motion;

When the single-mass planar three-axis MEMS inertial sensor is used to simultaneously sense planar inertial motions in multiple axes,

(1) If the capacitance value of C1 is the minimum value among the measured capacitance values of each side capacitance, the sensed plane inertial motion is the in-plane horizontal forward linear acceleration motion, the in-plane horizontal leftward linear acceleration motion, and the in-plane horizontal acceleration motion at the same time. Horizontal left-handed angular movement;

(2) If the capacitance value of C2 is the minimum value among the measured capacitance values of each side capacitance, the sensed plane inertial motion is the in-plane horizontal forward linear acceleration motion, the in-plane horizontal rightward linear acceleration motion, and the in-plane horizontal linear acceleration motion made at the same time. Horizontal right-handed angular movement;

(3) If the capacitance value of C3 is the minimum value among the measured capacitance values of each side capacitance, the sensed plane inertial motion is the in-plane horizontal backward linear acceleration motion, the in-plane horizontal rightward linear acceleration motion, and the in-plane horizontal linear acceleration motion made at the same time. Horizontal right-handed angular movement;

(4) If the capacitance value of C4 is the minimum value among the measured capacitance values of each side capacitance, the sensed plane inertial motion is the in-plane horizontal backward linear acceleration motion, the in-plane horizontal leftward linear acceleration motion, and the in-plane horizontal acceleration motion at the same time. Horizontal right-handed angular movement;

⑸ If the capacitance value of C5 is the minimum value among the measured capacitance values of each side capacitance, the sensed plane inertial motion is the in-plane horizontal backward linear acceleration motion, the in-plane horizontal leftward linear acceleration motion, and the in-plane horizontal acceleration motion at the same time. Horizontal left-handed angular movement;

⑹ If the capacitance value of C6 is the minimum value among the measured capacitance values of each side capacitance, the sensed plane inertial motion is the in-plane horizontal forward linear acceleration motion, the in-plane horizontal leftward linear acceleration motion, and the in-plane horizontal linear acceleration motion made at the same time. Horizontal right-handed angular movement;

⑺If the capacitance value of C7 is the minimum value among the measured capacitance values of each side capacitance, the sensed plane inertial motion is the in-plane horizontal backward linear acceleration motion, the in-plane horizontal rightward linear acceleration motion, and the in-plane horizontal linear acceleration motion at the same time. Horizontal right-handed angular movement;

⑻ If the capacitance value of C8 is the minimum value among the measured capacitance values of each side capacitance, the sensed plane inertial motion is the in-plane horizontal forward linear acceleration motion, the in-plane horizontal rightward linear acceleration motion, and the in-plane horizontal linear acceleration motion made at the same time. Horizontal left-handed angular movement.

The method for sensing in-plane linear acceleration motion and in-plane rotational angular motion using the single-mass plane three-axis MEMS inertial sensor includes the following steps:

(1) The single-mass plane three-axis MEMS inertial sensor is arranged at an appropriate position in the plane inertial motion system to be sensed;

(2) Connect the tiny capacitance detection circuit through each side capacitance output electrode and the ground output electrode;

(3) Measure the static capacitance value of each side capacitance and make necessary calibration;

⑷ Measure the output capacitance value of each side capacitor;

(5) Determine the direction of acceleration and/or angular velocity of the planar triaxial inertial motion sensed simultaneously or separately by the single-mass planar triaxial MEMS inertial sensor according to the aforementioned method for judging the type and direction of the sensed planar inertial motion.

(6) According to the in-plane horizontal linear acceleration motion and in-plane horizontal rotational angular motion sensed by the aforementioned single-mass planar three-axis MEMS inertial sensor, the offset and the in-plane horizontal offset generated between the inner and outer electrodes of the relevant side capacitors The relationship between the deflection amount of the in-plane horizontal deflection and the capacitance value change of each side capacitance, as well as the definitions of acceleration and angular velocity, calculate the acceleration value and in-plane linear acceleration motion sensed by the single-mass plane three-axis MEMS inertial sensor. Angular velocity value for rotational angular motion.

Preferably, the relationship between the capacitance value change of each side capacitance and the acceleration of in-plane linear acceleration motion and the angular velocity of in-plane rotational angular motion sensed by the single-mass planar three-axis MEMS inertial sensor can be obtained by measuring " Capacitance value change ~ acceleration, angular velocity" calibration table, and by fitting the calibration table data to obtain the corresponding calibration function or calibration curve method to determine;

Alternatively, the relationship between the capacitance value change of each side capacitance and the acceleration value of the in-plane linear acceleration motion and the angular velocity value of the in-plane rotational angular motion sensed by the single-mass planar three-axis MEMS inertial sensor can be determined by the finite element method. The method of model calculation to determine;

Alternatively, the relationship between the capacitance value change of each side capacitance and the acceleration value of the in-plane linear acceleration motion and the angular velocity value of the in-plane rotational angular motion sensed by the single-mass planar three-axis MEMS inertial sensor can be determined by the finite element method. software simulation method to determine.

The method for preparing the single-mass plane three-axis MEMS inertial sensor includes the following steps:

1. Making the bottom plate;

(1-1) Thermal oxidation or LPCVD of the top surface of the silicon single crystal substrate to form a silicon dioxide layer covering the top surface of the substrate;

(1-2) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the end face of the metal through hole of the base plate to be formed is located;

(1-3) Wet etching, removing the silicon dioxide layer in the area where the end face of the metal through hole of the base plate to be made is located, and removing the glue;

(1-4) dry etching, forming through silicon vias through the substrate, removing glue, and removing the silicon dioxide layer on the top surface of the substrate;

(1-5) Double-sided thermal oxidation or LPCVD of the above-mentioned substrate to form a silicon dioxide layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the TSV;

(1-6) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the through-silicon hole is located;

(1-7) magnetron sputtering, covering titanium film and gold film successively on the inner wall of the above-mentioned through-silicon hole, and removing the glue to obtain each bottom plate metal through-hole;

(1-8) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the lead electrode and the base plate bonding ring are located under the outer electrode of the side capacitor to be fabricated;

(1-9) magnetron sputtering, covering the titanium film and the gold film in turn;

(1-10) Remove the glue, together with removing the titanium-gold film on the photoresist film covering the lead-out electrodes under the external electrodes of the side capacitors and the area where the bonding ring of the base plate is located, to obtain the lead-out electrodes and the bottom plate under the external electrodes of each side capacitor bonding ring;

(1-11) Coat the bottom surface of the above-mentioned substrate with photoresist, expose and develop, and remove the photoresist film in the area where the output electrode of the side capacitor to be fabricated is located;

(1-12) Magnetron sputtering, covering the titanium film and the gold film in turn;

(1-13) Remove glue, together with removing the titanium-gold film covering the photoresist film outside the area where the side capacitor output electrodes are located, to obtain each side capacitor output electrode, and complete the production of the bottom plate;

2. Make a cavity structure layer;

(2-1) Thermal oxidation or LPCVD of the bottom surface of the silicon single crystal thick substrate to form a silicon dioxide layer covering the bottom surface of the substrate;

(2-2) Coat the bottom surface of the silicon single crystal thick substrate with photoresist, expose and develop, and remove the photoresist film in the area where the end face of the outer electrode of the side capacitor to be fabricated is located;

(2-3) Wet etching to remove the silicon dioxide layer in the area where the end face of the outer electrode of the side capacitor to be fabricated is located;

(2-4) dry etching, forming a side capacitor outer electrode groove through the substrate, removing the glue, and removing the silicon dioxide layer on the bottom surface of the substrate;

(2-5) Double-sided thermal oxidation or LPCVD of the above-mentioned substrate to form a silicon dioxide layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the outer electrode groove of the side capacitor;

(2-6) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the outer electrode groove of the side capacitor is located;

(2-7) magnetron sputtering titanium, covering the inner wall of the outer electrode groove of the side capacitor, then magnetron sputtering gold, filling the outer electrode groove of the side capacitor, removing the glue, and obtaining the outer electrode of each side capacitor;

(2-8) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the lead-out electrode on the side electrode to be fabricated and the bonding ring on the bottom surface of the cavity substrate are located;

(2-9) magnetron sputtering, covering the titanium film and the gold film in turn;

(2-10) Remove the glue, together with removing the titanium-gold film covering the lead-out electrodes on the external electrodes of the side capacitors and the photoresist film outside the area where the bonding ring on the bottom surface of the cavity substrate is located, to obtain the lead-out electrodes on the external electrodes of each side capacitor The electrode and the bonding ring on the bottom surface of the cavity substrate;

(2-11) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the bonding ring on the top surface of the cavity substrate to be fabricated is located;

(2-12) magnetron sputtering, covering titanium film, gold film and titanium film in sequence;

(2-13) Degumming, together with removing the titanium-gold-titanium film covering the photoresist film outside the area where the bonding ring on the top surface of the cavity substrate is located, to obtain the bonding ring on the top surface of the cavity substrate;

(2-14) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the cavity to be formed is located;

(2-15) Dry etching, sequentially removing the silicon dioxide layer on the top surface of the substrate, the silicon single crystal layer and the silicon dioxide layer on the bottom surface of the substrate in the area where the cavity is located, to form a cavity through the substrate, and make the side of the cavity The outer electrode of the side capacitor is exposed to complete the fabrication of the cavity structure layer;

3. Make the mass block and the cantilever beam structure layer;

(3-1) Prepare an SOI substrate, the SOI substrate is a silicon single crystal surface layer, a buried oxygen layer and a silicon single crystal support layer in order from top to bottom;

(3-2) Thermal oxidation or LPCVD on the top surface of the substrate to form a silicon dioxide layer covering the top surface of the substrate;

(3-3) Coating photoresist on the top surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the region where the end face of the metal through hole of the mass block to be prepared is located;

(3-4) wet etching, removing the silicon dioxide layer in the area where the end face of the metal through hole of the mass block to be made is located, and removing the glue;

(3-5) dry etching, forming through-silicon vias through the SOI substrate, removing the glue, and removing the silicon dioxide layer on the top surface;

(3-6) Double-sided thermal oxidation or LPCVD of the above-mentioned SOI substrate to form a silicon dioxide layer covering the top surface of the SOI substrate, the bottom surface of the SOI substrate and the inner wall of the TSV;

(3-7) Coating photoresist on the top surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the above-mentioned through-silicon hole is located;

(3-8) magnetron sputtering, sequentially covering the titanium film and the gold film on the inner wall of the above-mentioned through-silicon hole, and removing the glue to obtain a mass metal through-hole;

(3-9) Coating photoresist on the top surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the ground electrode to be prepared is located;

(3-10) Magnetron sputtering, covering the titanium film and the gold film in turn;

(3-11) Remove the glue, together with removing the titanium-gold film covering the photoresist film outside the area where the ground electrode is located, to obtain a ground electrode;

(3-12) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the end face of the inner electrode of the side capacitor to be fabricated is located;

(3-13) wet etching, removing the silicon dioxide layer on the bottom surface of the SOI substrate in the region where the end face of the inner electrode of the side capacitor to be fabricated is located;

(3-14) dry etching, removing the SOI substrate silicon single crystal support layer in the area where the inner electrode of the side capacitor to be fabricated is located, ending at the buried oxygen layer of the SOI substrate, obtaining the inner electrode groove of the side capacitor, and removing the glue;

(3-15) Thermal oxidation or LPCVD, covering the inner wall of the above-mentioned side capacitor inner electrode trench with a silicon dioxide layer;

(3-16) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the inner electrode groove of the side capacitor is located;

(3-17) magnetron sputtering titanium, covering the inner wall of the inner electrode groove of the side capacitor, then magnetron sputtering gold, filling the inner electrode groove of the side capacitor, removing the glue, and obtaining the inner electrode of each side capacitor;

(3-18) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area where the side capacitor inner electrode leads out the electrode;

(3-19) magnetron sputtering, covering the titanium film and the gold film in turn;

(3-20) Glue removal, together with removing the titanium-gold film on the photoresist film outside the area where the side capacitor inner electrode lead-out electrode is located, to obtain the side capacitor inner electrode lead-out electrode;

(3-21) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film outside the area where the inner electrode extraction electrode of the capacitor on the bottom surface of the mass block to be produced is located;

(3-22) Wet etching to remove the silicon dioxide layer on the bottom surface of the SOI substrate outside the area where the inner electrode of the capacitor on the bottom surface of the mass block to be produced is located;

(3-23) Dry etching, remove the SOI substrate silicon single crystal support layer outside the area where the mass block to be fabricated is located, stop at the position corresponding to the bottom surface of the cantilever beam fixing frame to be fabricated, remove the glue, and remove the bottom surface of the substrate 2 Silicon oxide layer;

(3-24) LPCVD, covering a silicon dioxide layer on the bottom surface of the above-mentioned SOI substrate;

(3-25) Coating photoresist on the bottom surface of the above-mentioned SOI substrate, exposing and developing, removing the photoresist film in the area between the mass block to be manufactured and the cantilever beam fixing frame to be manufactured;

(3-26) wet etching, removing the silicon dioxide layer in the area between the mass block to be made and the cantilever beam fixing frame to be made;

(3-27) Dry etching, removing the SOI substrate silicon single crystal support layer in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated, ending at the buried oxygen layer of the SOI substrate, so that each side of the mass block side The inner electrode of the capacitor is exposed, the lower structure of the mass block is obtained, and the glue is removed;

(3-28) Wet etching to remove the SOI substrate buried oxygen layer in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated, as well as the dioxide on the bottom surface of the mass block, the side surface of the mass block and the bottom surface of the cantilever beam fixing frame The silicon layer forms the bottom surface of each cantilever beam and the bottom surface of the cantilever beam fixing frame;

(3-29) Coat the photoresist on the top surface of the SOI substrate, expose and develop, and remove the photoresist film outside the area where the ground electrode obtained in steps (3-9) to (3-11) is located;

(3-30) Dry etching, sequentially removing the silicon dioxide layer on the top surface of the SOI substrate and the silicon single crystal surface layer of the SOI substrate outside the area where the ground electrode is located, and removing the glue to obtain the mass block, each cantilever beam and the cantilever beam fixing support Frame, complete the production of mass block and cantilever beam structure layer;

4. Make the top plate;

(4-1) Thermal oxidation or LPCVD of the top surface of the silicon single crystal substrate to form a silicon dioxide layer covering the top surface of the substrate;

(4-2) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the end face of the metal through hole of the top plate to be formed is located;

(4-3) Wet etching, removing the silicon dioxide layer in the area where the end face of the metal through hole of the top plate to be made is located, and removing the glue;

(4-4) dry etching, forming through silicon vias, removing glue, and removing the silicon dioxide layer on the top surface of the substrate;

(4-5) Double-sided thermal oxidation or LPCVD to form a silicon dioxide layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the TSV;

(4-6) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the above-mentioned through-silicon hole is located;

(4-7) Magnetron sputtering, sequentially covering titanium film and gold film on the inner wall of the above-mentioned through-silicon hole, and removing the glue to obtain each top plate metal through-hole;

(4-8) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the ground output electrode to be prepared is located;

(4-9) Magnetron sputtering, covering titanium film and gold film;

(4-10) removing the glue, together with removing the titanium-gold film covering the photoresist film outside the area where the grounded output electrode is located, to obtain each grounded output electrode;

(4-11) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the grounding lead-out electrode to be prepared is located;

(4-12) Magnetron sputtering, covering titanium film and gold film;

(4-13) Glue removal, together with removing the titanium-gold film covering the photoresist film outside the area where the grounding lead-out electrode is located, to obtain the grounding lead-out electrode;

(4-14) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the cavity of the top plate to be formed is located;

(4-15) Wet etching to remove the silicon dioxide layer in the region where the cavity of the top plate to be fabricated is located;

(4-16) dry etching, removing the silicon single crystal layer on the bottom surface of the above-mentioned substrate where the top plate cavity to be formed is located, and ending at a position where the thickness of the substrate is half, to obtain the top plate cavity, and completing the fabrication of the top plate;

5. Structural layer bonding;

(5-1) Align the bonding ring on the top surface of the cavity substrate on the top surface of the cavity structure layer with the bottom surface of the cantilever beam fixing frame, put it into the bonding machine, and heat up from room temperature to the set bonding Temperature, maintain the set bonding time under the set bonding pressure, and then naturally cool down to room temperature to complete the gold-silicon bonding between the cavity structure layer and the mass block and the cantilever structure layer;

(5-2) Align the bottom plate bonding ring on the top surface of the bottom plate and the lead-out electrodes on the outer electrodes of each side capacitor with the top surface bonding ring of the cavity substrate on the bottom surface of the cavity structure layer and the bottom lead-out electrodes of each side capacitor external electrode, respectively. Lamination, put it into the bonding machine, raise the temperature from room temperature to the set bonding temperature, maintain the set bonding time under the set bonding pressure, and then naturally cool down to room temperature to complete the bottom plate and the cavity structure layer The gold-gold bond;

(5-3) Align and fit the grounding lead-out electrode on the bottom surface of the top plate and the grounding electrode on the top surface of the cantilever beam fixing frame, put it into the bonding machine, and raise the temperature from room temperature to the set bonding temperature. The set bonding time is maintained under the bonding pressure, and then the temperature is naturally cooled to room temperature to complete the gold-gold bonding of the top plate and the cantilever beam fixed frame.

The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features according to the disclosed technical contents without creative work. Modifications, replacements and modifications are all within the protection scope of the present invention.

Claims (10)

1. A single-mass plane three-axis MEMS inertial sensor, characterized in that it comprises a bottom plate (1), a cavity structure layer (2), a mass block and a cantilever beam structure layer (3) bonded sequentially from bottom to top , top plate (4); The bottom plate (1) comprises a bottom plate substrate (11), four groups of side capacitor output electrodes (12) symmetrically distributed on the bottom surface of the bottom plate substrate with respect to the center thereof, and four groups of side capacitor external electrodes symmetrically distributed on the top surface of the bottom plate substrate with respect to the center thereof The bottom lead-out electrode (13), the bottom plate bonding ring (14) of the bottom lead-out electrode (13) surrounding four groups of side capacitor external electrodes on four sides on the top surface of the bottom plate substrate, and 8 bottom plate metal through holes (15) penetrating the bottom plate substrate; The cavity structure layer (2) includes a cavity substrate (21), a regular octagonal prism cavity (22) penetrating the middle of the cavity substrate, and four groups of 4 groups arranged alternately on four inner surfaces of the cavity (22) on the front, rear, left, right, and right of the cavity (22). The side capacitor external electrodes (23), the lead electrodes (24) on the four groups of side capacitor external electrodes whose bottom surface of the cavity substrate faces the four groups of side capacitor external electrodes, and the four groups of side capacitor external electrodes on the bottom surface of the cavity substrate are surrounded by four groups of lead electrodes ( 24) bonding ring (25) on the bottom surface of the cavity substrate and a bonding ring (26) on the top surface of the cavity substrate surrounding the four sides of the top surface of the cavity substrate; The mass block and the cantilever beam structure layer (3) include a regular octagonal prismatic mass block (31), four side capacitor inner electrodes (32) covering the four sides of the mass block at the front, back, left and right, and four inner electrodes (32) covering the bottom surface of the mass block. The inner electrode lead-out electrode (33) of the side capacitor, the mass metal through hole (34) passing through the center of the mass block, four S-shaped cantilever beams (35), the cantilever beam fixing frame (36) and covering the top surface of the mass block, each the ground electrode (37) on the top surface of the cantilever beam and the top surface of the cantilever beam fixing frame; The top plate (4) comprises a top plate substrate (41), a top plate cavity (42) in the middle of the bottom surface of the top plate substrate, grounding lead-out electrodes (43) covering the four sides of the bottom surface of the top plate substrate, and four sides of the top plate substrate are symmetrically distributed with respect to the center thereof. 4 grounding output electrodes (44) and 4 top plate metal through holes (45) penetrating through the top plate substrate; The bottom surface bonding ring (25) of the cavity substrate on the bottom surface of the cavity structure layer (2) is gold-gold bonded with the bottom plate bonding ring (14) on the top surface of the bottom plate (1); The bottom surface is gold-silicon bonded with a bonding ring (26) on the top surface of the cavity substrate on the top surface of the cavity structure layer (2), each cantilever beam is suspended on the cavity (22) and the mass block (31) is suspended in the air In the cavity (22); the grounding lead-out electrode (43) on the bottom surface of the top plate (4) is gold-gold bonded with the grounding electrode (37) on the top surface of the cantilever beam fixing frame (36) to finally form a hermetically sealed structure. 2 . The single-mass planar three-axis MEMS inertial sensor according to claim 1 , wherein the base plate substrate ( 11 ) is a base plate with a square cross-section, and correspondingly, the base plate bonding ring ( 14 ) is an inner side and an outer side. 3 . Rectangular ring of square section; Each group of side capacitor output electrodes includes two parallel side capacitor output electrodes (12), and each side capacitor output electrode (12) is a rectangular electrode of the same shape; The lower lead-out electrodes of each group of side capacitor outer electrodes comprise two parallel side capacitor outer electrodes lower lead-out electrodes (13), and the lower lead-out electrodes (13) of each side capacitor outer electrode are rectangular electrodes of the same shape; Each side capacitor output electrode (12) is directly opposite to the lower lead-out electrode (13) of one side capacitor outer electrode and is connected by a bottom metal through hole (15). 3. The single-mass planar three-axis MEMS inertial sensor according to claim 1, characterized in that the cavity substrate (21) is a thick substrate with a square outer edge, and correspondingly, the bottom surface of the cavity substrate is bonded Both the ring (25) and the top surface bonding ring (26) of the cavity substrate are rectangular rings with inner and outer cross sections; Each group of side capacitor outer electrodes includes two side capacitor outer electrodes (23) in parallel, each side capacitor outer electrode (23) is a rectangular electrode of the same shape, and the height of each side capacitor outer electrode (23) is the same as the cavity (22) The heights are the same, and the total width of the two side capacitor external electrodes (23) and their gaps in each group of side capacitor external electrodes is the same as the total width of the mass block and the regular octagonal prism-shaped mass block (31) in the cantilever beam structure layer (3). The width of the inner electrodes (32) of the side capacitors is the same; The lead-out electrodes on the outer electrodes of the side capacitors of each group include two parallel lead-out electrodes (24) on the outer electrodes of the side capacitors, and the lead-out electrodes (24) on the outer electrodes of each side capacitor are rectangular electrodes of the same shape, and the outer electrodes of the respective side capacitors are of the same shape. The inner end of the upper lead-out electrode (24) is connected with the lower end of the corresponding side capacitor outer electrode (23). 4. The single-mass planar three-axis MEMS inertial sensor according to claim 3, wherein the upper end of each side capacitance inner electrode (32) is flush with the lower surface of each S-shaped cantilever beam (35), The lower end of each side capacitor inner electrode (32) is connected with the outer edge of the side capacitor inner electrode lead-out electrode (33), and the mass metal through hole (34) is connected to the side capacitor inner electrode lead-out electrode (33) on the bottom surface of the mass block ) and the ground electrode (37) on the top surface of the mass; The cantilever beam fixing frame (36) is a hollow frame with an inner square and an outer square; Each S-shaped cantilever beam (35) includes several radial arms (351), several transverse arms (352), an inner radial support arm (353) and an outer radial support arm (354); each The radial arm and each transverse arm have the same length and the same width, and the length of each radial arm and each transverse arm is at least 4 times its width; each inner radial support arm and each outer radial support arm have the same The length and the same width, the length of each inner radial support arm and each outer radial support arm is not greater than its width, and the width of each inner radial support arm and each outer radial support arm is not less than 1/ of the length of the transverse arm 2; each radial arm, transverse arm, inner radial support arm, and outer radial support arm have the same thickness, and the thickness of each radial arm, transverse arm, inner radial support arm, and outer radial support arm is at least the 2 times the width of the lateral or lateral arm; In each S-shaped cantilever beam, the inner radial support arm, several transverse arms, several radial arms, and outer radial support arms are connected orthogonally in turn, wherein each transverse arm and each radial arm are connected orthogonally in turn, so The S-shaped cantilever beams are alternately connected to the center of the top ends of the front, rear, left and right sides of the mass block through the inner ends of the inner radial support arms, and the S-shaped cantilever beams are alternately connected to the outer ends of the outer radial support arms. The center of the inner top of the front, rear, left and right sides of the cantilever beam fixing frame, the top surface of each S-shaped cantilever beam is flush with the top surface of the mass block and the top surface of the cantilever beam fixing frame. 5. The single-mass planar three-axis MEMS inertial sensor according to claim 1, characterized in that, the top plate substrate (41) is a substrate with a square outer edge, and correspondingly, the ground lead-out electrodes (43) on the four sides of the bottom surface of the top plate substrate ) is a rectangular ring with inner and outer cross-section; The cross section of the top plate cavity (42) is identical to the cross section of the hollow part of the cantilever beam fixing frame (36), and the depth of the top plate cavity (42) is half the thickness of the top plate base plate (41); Each grounding output electrode (44) is a rectangular electrode of the same shape, and the four top metal through holes (45) are respectively connected to the four grounding output electrodes (44) and the grounding lead-out electrode (43). 6. The single-mass planar three-axis MEMS inertial sensor according to claim 1, characterized in that the bottom plate substrate (11), the cavity substrate (21), the cantilever beam fixing frame (36) and the top plate substrate ( 41) The outer edge of a square with the same side length; The bottom surface bonding ring (14), the bottom surface bonding ring (25) of the cavity substrate, the top surface bonding ring (26) of the cavity substrate, the bottom surface of the cantilever beam fixing frame (36) and the cantilever beam fixing frame ( 36) The grounding lead-out electrodes (43) on the bottom surface of the top board substrate (41) are identical; Each electrode, each bonding ring and the substrate where it is located, and between each metal through hole and the penetrating substrate are electrically isolated by an insulating layer (5); The substrate material of the top plate (1), the cavity structure layer (2) and the bottom plate (4) is silicon single crystal, the substrate for making the mass block and the cantilever beam structure layer (3) is an SOI substrate, and each electrode and each bonding The material of the ring and each metal through hole is gold, and the material of the insulating layer (5) is silicon dioxide or silicon nitride. 7 . The single-mass planar three-axis MEMS inertial sensor according to claim 2 , wherein the mass is suspended in the cavity, and the gap between the outer surface of the mass and the inner surface of the cavity is the mass. 8 . Relative to the cavity, it is a space for in-plane horizontal offset back and forth, in-plane horizontal left-right offset, and in-plane horizontal left-right rotation; The 4 side capacitor inner electrodes and the opposite 8 side capacitor outer electrodes form 8 side capacitors (6), wherein the two side capacitors (61, 62) located on the front side of the mass block form a first sensing capacitor pair, The two side capacitors (63, 64) located on the rear side of the mass block form the second sensing capacitor pair, and the two side capacitors (65, 66) located on the left side of the mass block form the third sensing capacitor pair, located on the right side of the mass block The two side capacitors (67, 68) on the side form a fourth sensing capacitor pair. 8 . The single-mass planar three-axis MEMS inertial sensor according to claim 1 , wherein, when static, the 8 outer sides of the mass suspended in the cavity are respectively opposite to the 8 inner sides of the cavity. 9 . Parallel, facing and maintaining an equal distance, the bottom surface of the mass block and the top surface of the bottom plate and the top surface of the mass block and the top surface of the top plate cavity are parallel and maintain the initial distance; Correspondingly, the 4 side capacitor inner electrodes on the outer surface of the mass block are respectively parallel to, facing each other and keep the same gap width with the opposite 4 groups of side capacitor outer electrodes, forming the static insulation gap of the 8 side capacitors, the 8 side capacitors. With the same static capacitance value, the 8 side capacitance output ports formed by each side capacitance output electrode and each ground output electrode output the same static capacitance value signal. 9. The single-mass plane three-axis MEMS inertial sensor according to claim 4, wherein 4 symmetrically distributed S-shaped cantilevers support the mass, and each S-shaped cantilever is suspended on the cavity and makes the The mass is suspended in the cavity, where: The radial arms and transverse arms of each S-shaped cantilever beam are long and narrow thick beams with the same length, which are easy to produce in-plane radial deformation and in-plane transverse deformation, but are not easy to produce out-of-plane bending deformation; The inner radial support arm and the outer radial support arm of each S-shaped cantilever beam are short and wide thick beams, which are not prone to in-plane bending deformation and out-of-plane bending deformation. 10. a preparation method of inertial sensor as claimed in claim 1 is characterized in that, comprises the following steps: 1. Making the bottom plate; (1-1) Thermal oxidation or LPCVD of the top surface of the silicon single crystal substrate to form an oxide insulating layer covering the top surface of the substrate; (1-2) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the end face of the metal through hole of the base plate to be formed is located; (1-3) Wet etching, removing the oxide insulating layer in the area where the end face of the metal through hole of the base plate to be made is located, and removing the glue; (1-4) Dry etching to form through-silicon vias through the substrate, remove glue, and remove the oxide insulating layer on the top surface of the substrate; (1-5) Double-sided thermal oxidation or LPCVD of the above-mentioned substrate to form an oxide insulating layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the TSV; (1-6) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the through-silicon hole is located; (1-7) Magnetron sputtering, covering the inner wall of the above-mentioned through-silicon hole with a titanium film and a gold film in turn, and removing the glue to obtain each bottom metal through-hole; (1-8) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, removing the photoresist film in the area where the lead-out electrode and the base plate bonding ring are located under the outer electrode of the side capacitor to be fabricated; (1-9) Magnetron sputtering, covering titanium film and gold film in turn; (1-10) Remove the glue, together with removing the titanium-gold film on the photoresist film covering the lead-out electrodes under the external electrodes of the side capacitors and the area where the bonding ring of the base plate is located, to obtain the lead-out electrodes and the bottom plate under the external electrodes of each side capacitor bonding ring; (1-11) Coat the bottom surface of the substrate with photoresist, expose and develop, and remove the photoresist film in the area where the output electrode of the side capacitor to be fabricated is located; (1-12) Magnetron sputtering, covering titanium film and gold film in turn; (1-13) Remove the glue, together with removing the titanium-gold film covering the photoresist film outside the area where the side capacitor output electrodes are located, to obtain each side capacitor output electrode, and complete the production of the bottom plate; 2. Make a cavity structure layer; (2-1) Thermal oxidation or LPCVD of the bottom surface of the silicon single crystal thick substrate to form an oxide insulating layer covering the bottom surface of the substrate; (2-2) Coat the bottom surface of the silicon single crystal thick substrate with photoresist, expose and develop, and remove the photoresist film in the area where the end face of the outer electrode of the side capacitor to be fabricated is located; (2-3) Wet etching to remove the oxidized insulating layer in the area where the end face of the outer electrode of the capacitor to be fabricated is located; (2-4) Dry etching to form the outer electrode groove of the side capacitor through the substrate, remove the glue, and remove the oxide insulating layer on the bottom surface of the substrate; (2-5) The above-mentioned substrate is double-sided thermal oxidation or LPCVD to form an oxide insulating layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the outer electrode trench of the side capacitor; (2-6) Coat photoresist on the bottom surface of the above-mentioned substrate, expose and develop, and remove the photoresist film in the area where the outer electrode groove of the side capacitor is located; (2-7) Magnetron sputtering titanium, covering the inner wall of the outer electrode groove of the side capacitor, and then magnetron sputtering gold, filling the outer electrode groove of the side capacitor, and removing the glue to obtain the outer electrodes of each side capacitor; (2-8) Coat the bottom surface of the substrate with photoresist, expose and develop, and remove the photoresist film in the area where the lead-out electrode on the external electrode of the side capacitor to be fabricated and the bonding ring on the bottom surface of the cavity substrate are located; (2-9) Magnetron sputtering, covering titanium film and gold film in turn; (2-10) Remove the glue, together with removing the titanium-gold film covering the lead-out electrodes on the external electrodes of the side capacitors and the photoresist film outside the area where the bonding ring on the bottom surface of the cavity substrate is located to obtain the lead-out electrodes on the external electrodes of each side capacitor The electrode and the bonding ring on the bottom surface of the cavity substrate; (2-11) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the bonding ring on the top surface of the cavity substrate to be fabricated is located; (2-12) Magnetron sputtering, covering titanium film, gold film and titanium film in sequence; (2-13) Degumming, together with removing the titanium-gold-titanium film covering the photoresist film outside the area where the bonding ring on the top surface of the cavity substrate is located, to obtain the bonding ring on the top surface of the cavity substrate; (2-14) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the cavity to be formed is located; (2-15) Dry etching, sequentially removing the oxidized insulating layer on the top surface of the substrate, the silicon single crystal layer and the oxidized insulating layer on the bottom surface of the substrate in the area where the cavity is located to form a cavity through the substrate, and make the side capacitance on the side of the cavity The outer electrode is exposed to complete the fabrication of the cavity structure layer; 3. Make the mass block and the cantilever beam structure layer; (3-1) Prepare an SOI substrate, the SOI substrate is a silicon single crystal surface layer, a buried oxide layer and a silicon single crystal support layer in order from top to bottom; (3-2) Thermal oxidation or LPCVD of the top surface of the substrate to form an oxide insulating layer covering the top surface of the substrate; (3-3) Coat the top surface of the SOI substrate with photoresist, expose and develop, and remove the photoresist film in the area where the end face of the metal through hole of the mass block to be produced is located; (3-4) Wet etching, remove the oxide insulating layer in the area where the end face of the metal through hole of the mass block to be made is located, and remove the glue; (3-5) Dry etching to form through-silicon vias penetrating the SOI substrate, remove glue, and remove the oxide insulating layer on the top surface of the substrate; (3-6) Double-sided thermal oxidation or LPCVD of the above-mentioned SOI substrate to form an oxide insulating layer covering the top surface of the SOI substrate, the bottom surface of the SOI substrate and the inner wall of the TSV; (3-7) Coating photoresist on the top surface of the above-mentioned SOI substrate, exposing and developing, and removing the photoresist film in the area where the above-mentioned through-silicon hole is located; (3-8) Magnetron sputtering, covering the inner wall of the above-mentioned through-silicon hole with a titanium film and a gold film in turn, and removing the glue to obtain a mass metal through-hole; (3-9) Coat the top surface of the SOI substrate with photoresist, expose and develop, and remove the photoresist film in the area where the ground electrode to be fabricated is located; (3-10) Magnetron sputtering, covering the titanium film and the gold film in turn; (3-11) Remove the glue, together with removing the titanium-gold film covering the photoresist film outside the area where the ground electrode is located, to obtain the ground electrode; (3-12) Coat the bottom surface of the SOI substrate with photoresist, expose and develop, and remove the photoresist film in the area where the end face of the inner electrode of the side capacitor to be fabricated is located; (3-13) Wet etching to remove the oxidized insulating layer on the bottom surface of the SOI substrate in the area where the end face of the inner electrode of the capacitor to be fabricated is located; (3-14) Dry etching, removing the SOI substrate silicon single crystal support layer in the area where the inner electrode of the side capacitor to be fabricated is located, ending at the buried oxygen layer of the SOI substrate, obtaining the inner electrode groove of the side capacitor, and removing the glue; (3-15) Thermal oxidation or LPCVD, covering the inner wall of the above-mentioned side capacitor inner electrode trench with an oxide insulating layer; (3-16) Coat the bottom surface of the SOI substrate with photoresist, expose and develop, and remove the photoresist film in the area where the inner electrode groove of the side capacitor is located; (3-17) Magnetron sputtering titanium, covering the inner wall of the inner electrode groove of the side capacitor, and then magnetron sputtering gold, filling the inner electrode groove of the side capacitor, and removing the glue to obtain the inner electrode of each side capacitor; (3-18) Coat the bottom surface of the SOI substrate with photoresist, expose and develop, and remove the photoresist film in the area where the inner electrode of the side capacitor is located; (3-19) Magnetron sputtering, covering titanium film and gold film in turn; (3-20) Remove the glue, together with removing the titanium-gold film on the photoresist film covering the area where the side capacitor inner electrode lead-out electrode is located, to obtain the side capacitor inner electrode lead-out electrode; (3-21) Coat the bottom surface of the SOI substrate with photoresist, expose and develop, and remove the photoresist film outside the area where the inner electrode of the capacitor on the bottom surface of the mass block to be produced is located outside the area where the lead-out electrode is located; (3-22) Wet etching to remove the oxidized insulating layer on the bottom surface of the SOI substrate outside the area where the lead-out electrodes of the capacitor inner electrodes are located on the bottom surface of the mass block to be fabricated; (3-23) Dry etching, remove the SOI substrate silicon single crystal support layer outside the area where the mass block to be fabricated is located, stop at the position corresponding to the bottom surface of the cantilever beam fixing frame to be fabricated, remove the glue, and remove the oxidation on the bottom surface of the substrate Insulation; (3-24) LPCVD, covering the bottom surface of the SOI substrate with an oxide insulating layer; (3-25) Coat the bottom surface of the SOI substrate with photoresist, expose and develop, and remove the photoresist film in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated; (3-26) Wet etching to remove the oxide insulating layer in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated; (3-27) Dry etching, remove the SOI substrate silicon single crystal support layer in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated, and stop at the buried oxygen layer of the SOI substrate, so that each side of the mass block side is removed. The inner electrode of the capacitor is exposed, the lower structure of the mass block is obtained, and the glue is removed; (3-28) Wet etching to remove the buried oxygen layer of the SOI substrate in the area between the mass block to be fabricated and the cantilever beam fixing frame to be fabricated, as well as the oxide insulation on the bottom surface of the mass block, the side surface of the mass block and the bottom surface of the cantilever beam fixing frame layer, forming the bottom surface of each cantilever beam and the bottom surface of the cantilever beam fixing frame; (3-29) Coat the top surface of the SOI substrate with photoresist, expose and develop, and remove the photoresist film outside the area where the ground electrode obtained in steps (3-9) to (3-11) is located; (3-30) Dry etching, sequentially removing the oxide insulating layer on the top surface of the SOI substrate and the silicon single crystal surface layer of the SOI substrate outside the area where the ground electrode is located, and removing the glue to obtain the mass block, each cantilever beam and the cantilever beam fixing frame , to complete the production of the mass block and the cantilever beam structure layer; 4. Make the top plate; (4-1) Thermal oxidation or LPCVD of the top surface of the silicon single crystal substrate to form an oxide insulating layer covering the top surface of the substrate; (4-2) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the end face of the metal through hole of the top plate to be formed is located; (4-3) Wet etching, remove the oxide insulating layer in the area where the end face of the metal through hole of the top plate to be fabricated is located, and remove the glue; (4-4) Dry etching to form through silicon vias, remove glue, and remove the oxide insulating layer on the top surface of the substrate; (4-5) Double-sided thermal oxidation or LPCVD to form an oxide insulating layer covering the top surface of the substrate, the bottom surface of the substrate and the inner wall of the TSV; (4-6) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the above-mentioned through-silicon hole is located; (4-7) Magnetron sputtering, covering the inner wall of the above-mentioned through-silicon hole with a titanium film and a gold film in turn, and removing the glue to obtain each top plate metal through-hole; (4-8) Coating photoresist on the top surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the ground output electrode to be prepared is located; (4-9) Magnetron sputtering, covering titanium film and gold film; (4-10) Remove the glue, together with removing the titanium-gold film covering the photoresist film outside the area where the grounded output electrode is located, to obtain each grounded output electrode; (4-11) Coat the bottom surface of the above-mentioned substrate with photoresist, expose and develop, and remove the photoresist film in the area where the grounding lead-out electrode to be prepared is located; (4-12) Magnetron sputtering, covering titanium film and gold film; (4-13) Remove the glue, together with removing the titanium-gold film covering the photoresist film outside the area where the grounded lead-out electrode is located, to obtain the grounded lead-out electrode; (4-14) Coating photoresist on the bottom surface of the above-mentioned substrate, exposing and developing, and removing the photoresist film in the area where the cavity of the top plate to be formed is located; (4-15) Wet etching to remove the oxide insulating layer in the area where the cavity of the top plate to be fabricated is located; (4-16) dry etching, removing the silicon single crystal layer on the bottom surface of the substrate where the top plate cavity to be formed is located, and ending at a position where the thickness of the substrate is half, to obtain the top plate cavity, and complete the fabrication of the top plate; 5. Structural layer bonding; (5-1) Align the bonding ring on the top surface of the cavity substrate on the top surface of the cavity structure layer with the bottom surface of the cantilever beam fixing frame, put it into the bonding machine, and heat up from room temperature to the set bonding Temperature, maintain the set bonding time under the set bonding pressure, and then naturally cool down to room temperature to complete the gold-silicon bonding between the cavity structure layer and the mass block and the cantilever structure layer; (5-2) Align the bottom plate bonding ring on the top surface of the bottom plate and the bottom lead-out electrode of each side capacitor external electrode with the bottom surface of the cavity substrate bottom surface of the cavity structure layer and the lead electrode on each side capacitor external electrode. Then put it into the bonding machine, raise the temperature from room temperature to the set bonding temperature, keep the set bonding time under the set bonding pressure, and then naturally cool down to room temperature to complete the bonding between the bottom plate and the cavity structure layer. gold-gold bonding; (5-3) Align the grounding lead-out electrode on the bottom surface of the top plate with the grounding electrode on the top surface of the cantilever beam fixing frame, put it into the bonding machine, and heat up from room temperature to the set bonding temperature. The set bonding time is maintained under the bonding pressure, and then the temperature is naturally cooled to room temperature to complete the gold-gold bonding of the top plate and the cantilever beam fixed frame.

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