CN105698781B - Radial support bulk acoustic wave silicon micro-gyroscope - Google Patents

Abstract

The invention discloses a radially supported body acoustic wave silicon micro-gyroscope, comprising a disc-shaped resonator, a lateral support arm, a circular arc-shaped driving electrode, a capacitance detection electrode with a displacement amplifying mechanism, a detection electrode fixing boss and a substrate . The gyroscope adopts the two in-plane four-wave-node frequency matching modes of the disc-shaped resonator as the driving mode and detection mode. All the structures of the gyroscope are realized on the <111> silicon wafer by the micro-machine electronic processing technology. The gyroscope supports the disc-shaped resonator in a lateral support manner, and measures the input of the angular velocity by amplifying the displacement output of the detection mode through electrostatic drive and triangular amplifying mechanism, which improves the sensitivity of the gyroscope and simplifies the operation of the bulk acoustic wave silicon micro-gyroscope. The manufacturing process reduces the production cost, improves the impact resistance of the gyroscope, reduces the zero offset of the gyroscope, and improves the accuracy of the gyroscope.

Description

Radial support bulk acoustic wave silicon micro-gyroscope

Technical field

The present invention relates to a kind of microthrust tests of field of micro electromechanical technology, specifically, what is involved is a kind of radial branch Support body sound wave silicon micro-gyroscope.

Background technique

Gyroscope be it is a kind of using micromechanics electronics (MEMS) technique production being capable of sensitive carrier angle or angular speed Inertia device, have very important effect in the fields such as gesture stability and navigator fix.Have benefited from recent micro-electronic machining The progress of technology, silicon micro-gyroscope is since processing technology can obtain quick development with ic process compatibility, volume Small, the silicon micro-gyroscope that low energy consumption is in consumer electronics attitude control system, automobile assisting navigation and safety control system, industrial machine Device people gesture stability, weapon inertial guidance etc. are widely used.

Bulk acoustic wave silicon micro-gyroscope is that New Solid MEMS gyroscope is made of bulk acoustic wave technologies, compares existing top Spiral shell instrument has the advantage that smaller, dynamic response is good, high reliablity, cost is lower, CMOS technology easy to accomplish is integrated. Existing MEMS gyroscope technology measures angular speed using mass block low-frequency vibration (5 ~ 50kHz), and bulk acoustic wave MEMS gyro The working frequency of instrument is several orders of magnitude higher, and is megahertz range (1 ~ 10MHz).The gyroscope made using bulk acoustic wave technologies is rigid Degree is higher, this not only makes gyroscope insensitive to the vibration in environment, can also prevent from adhering to during the manufacturing Problem, therefore improve the reliability and yield rate of MEMS device.In practical applications, often there is vibration is influencing gyroscope just Often work, and bulk acoustic wave MEMS gyroscope possesses outstanding performance.

Since bulk acoustic wave gyro disk harmonic oscillator rigidity is larger, working frequency is higher, driven-mode and detection mould The vibration amplitude of harmonic oscillator is all in 20nm or so, for the sensitivity for increasing gyro, arc-shaped driving electrodes and detecting electrode under state There was only 200nm with the capacitance gap between disc-shape harmonic oscillator, disk is 40 μm thick, and depth-to-width ratio is up to 200:1, capacitance gap Processing is very difficult, and since gap width is smaller, and sidewall surfaces roughness precision is difficult to control, and easily causes in the course of work Tunnelling；Caused supporting damping is vibrated to reduce cylindric support column in bulk acoustic wave gyroscope, increases the machinery of silicon micro-gyroscope The support column diameter of quality factor, gyroscope is very small, and control SiO is utilized in technique manufacturing process₂The etching of etching liquid Time controls SiO₂The method of support column diameter increases the technology difficulty of gyro；It is fixed with disk resonance subcenter Single minor diameter support column due to size it is smaller so that gyro impact resistance is weaker；Arc-shaped detection under driven-mode It exports and is not zero between electrode isotonic oscillator, increase the zero bias and noise of gyro, affect the measurement accuracy of gyro.

Summary of the invention

The present invention provides a kind of radial support bulk acoustic wave silicon micro-gyroscope in view of the deficiencies of the prior art, and gyroscope uses Disc-shape harmonic oscillator radial support replaces the scheme of disc-shape harmonic oscillator centered cylinder support, using triangular form displacement equations The method of mechanism amplification detection modal displacement output, improves the sensitivity of gyro, simplifies the processing of bulk acoustic wave silicon micro-gyroscope Technique improves the impact resistance of gyroscope, reduces the zero bias of gyro, improves the precision of gyro.

To achieve the above object, the present invention proposes the following technical solution: a kind of radial support bulk acoustic wave silicon micro-gyroscope, Including disc-shape harmonic oscillator, lateral support arm, there is the capacitance detecting electrode of displacement amplifying mechanism, detecting electrode fixation is convex Platform, arc-shaped driving electrodes and substrate.Gyroscope matches mould using four wave amplitude node frequencies in 2 faces of disc-shape harmonic oscillator State is as driven-mode and sensed-mode, driven-mode and the sensed-mode vibration shape having the same, and its radial vibration is orthogonal, i.e., The wave amplitude of driven-mode is the node of sensed-mode, and the node of driven-mode is the wave amplitude of sensed-mode.

There are four lateral support arm is total, four lateral support arms are located at the node of driven-mode radial vibration, and shape is Cuboid, lateral support arm one end are fixedly connected with disc-shape harmonic oscillator in radial direction, and the other end is same to have displacement equations The capacitance detecting electrode of mechanism is fixed.

Capacitance detecting electrode with displacement amplifying mechanism is by symmetrical two delta displacement enlargers and two A capacitor plate composition, delta displacement enlarger are the isosceles trapezoidal structure without bottom, and two waists of isosceles trapezoid are bullet Property beam, upper bottom edge is buckstay, and the angle between two waist of isosceles trapezoid is obtuse angle.The upper bottom edge of delta displacement enlarger is rigid It being fixedly connected between property beam and capacitor plate, capacitor plate is parallel to the upper bottom edge buckstay of delta displacement enlarger, and two Two waist spring beams of a delta displacement enlarger rigidly fix beam connection by two.Capacitor with displacement amplifying mechanism Detecting electrode one end is fixedly connected with lateral support arm, and the other end is fixedly connected with detecting electrode fixing lug boss, capacitor plate and Parallel capacitance gap is formed between detecting electrode fixing lug boss as detection capacitor.Capacitance detecting with displacement amplifying mechanism There are four electrode is total, the gap between capacitor plate and detecting electrode fixing lug boss is 1-10 μm, with displacement amplifying mechanism Capacitance detecting electrode improves its conductivity by the technique that heavy ion adulterates.

It is provided with the through hole being symmetrically and evenly distributed about the center of circle in disc-shape harmonic oscillator, the size in change hole can be passed through The rigidity of harmonic oscillator is adjusted, disc-shape harmonic oscillator improves its conductivity by the technique that heavy ion adulterates.

Arc-shaped driving electrodes and disc-shape harmonic oscillator are concentric, and arc-shaped driving electrodes are located at the drive of disc-shape harmonic oscillator At the wave amplitude of dynamic model state, altogether there are four, gap between arc-shaped driving electrodes and disc-shape harmonic oscillator is 1-10 μm, gap Depth-to-width ratio be less than 20:1, arc-shaped driving electrodes improve its conductivity by the technique that heavy ion adulterates.

The outer diameter and disc-shape harmonic oscillator of detecting electrode fixing lug boss are concentric, and detecting electrode fixing lug boss is located at disc On the corresponding radius extended line of the wave amplitude of shape harmonic oscillator sensed-mode, altogether there are four, the outer diameter and circle of detecting electrode fixing lug boss Arc driving electrodes outer diameter size is identical.

Substrate is disc, and substrate and disc-shape harmonic oscillator are concentric, radius and detecting electrode fixing lug boss and circular arc The outer diameter of shape driving electrodes is identical, and detecting electrode fixing lug boss and arc-shaped driving electrodes are fixed on substrate.

Disc-shape harmonic oscillator, lateral support arm, the capacitance detecting electrode with displacement amplifying mechanism, detecting electrode are fixed Boss, arc-shaped driving electrodes and substrate on the silicon wafer of<111>crystal orientation all by passing through micromechanics electronics processing technology system It forms.

The working principle of radial support bulk acoustic wave silicon micro-gyroscope of the present invention are as follows: apply same top in arc-shaped driving electrodes The electrostatic force when voltage drive signals of spiral shell driven-mode same frequency, between driving electrodes and disc-shape harmonic oscillator Under, gyro generates the vibration under driven-mode, and radial displacement is zero at lateral support arm under driven-mode vibration, therefore capacitor is examined Electrode is surveyed without output；When having along the turning rate input of disc-shape harmonic oscillator axis direction, the gyro meeting under corioliseffect The vibration under sensed-mode is generated, the radial displacement and radial force under sensed-mode vibration at lateral support arm are maximum, at two Under the action of delta displacement enlarger, the thin tail sheep output of sensed-mode is enlarged into the larger displacement output of capacitor plate, The movement of capacitor plate will lead to the variation of capacitor between capacitor plate and detecting electrode fixing lug boss, the variable quantity direct ratio of capacitor In the size of input angular velocity, input angular velocity can be detected by the size of measurement capacitance detecting electrode output.

Radial support bulk acoustic wave silicon micro-gyroscope of the present invention compare existing bulk acoustic wave gyroscope for it is advantageous that: Disc-shape harmonic oscillator is supported using lateral support arm at the node of disc-shape harmonic oscillator driven-mode, can effectively be reduced pair The influence of harmonic oscillator driven-mode, while the processing technology that the complexity for avoiding minor diameter support column is difficult to control, structure are simple It is easily achieved；The thin tail sheep output amplification that will test mode using two delta displacement enlargers, can be improved the spirit of gyro Sensitivity reduces the requirement to capacitance gap between driving electrodes and disc-shape harmonic oscillator；It is symmetrical lateral using four The mode of support arm substantially increases the impact resistance of gyro so that the support of gyro is more reliable；In no turning rate input Lateral support arm can reduce the zero bias of gyro without output, improve the precision of gyro without radial displacement, capacitance detecting electrode.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of radial support bulk acoustic wave silicon micro-gyroscope of the present invention.

Fig. 2 is the capacitance detecting electrode partial enlargement structural representation that the present invention has displacement amplifying mechanism.

Fig. 3 is the three dimensional structure diagram of radial support bulk acoustic wave silicon micro-gyroscope of the present invention.

Fig. 4 is the radial support bulk acoustic wave silicon micro-gyroscope driven-mode vibration shape of the present invention.

Fig. 5 is the radial support bulk acoustic wave silicon micro-gyroscope sensed-mode vibration shape of the present invention.

Specific embodiment

Below with reference to attached drawing 1, attached drawing 2, attached drawing 3, attached drawing 4, attached drawing 5 and a specific embodiment to radial branch of the invention Support body sound wave silicon micro-gyroscope is further detailed.

Radial support bulk acoustic wave silicon micro-gyroscope as shown in Figure 1, Figure 2 and Figure 3 includes disc-shape harmonic oscillator 1, lateral to prop up Brace 2a-2d, arc-shaped driving electrodes 3a-3d, the capacitance detecting electrode 4a-4d with displacement amplifying mechanism, detecting electrode are solid Determine boss 5a-5d and substrate 6.Gyroscope is using four wave amplitude waves in two faces of disc-shape harmonic oscillator 1 as shown in Figure 4 and Figure 5 Frequency matching mode is saved as driven-mode and sensed-mode, driven-mode and the sensed-mode vibration shape having the same, and its diameter Orthogonal to vibrating, i.e., the wave amplitude of driven-mode is the node of sensed-mode, and the node of driven-mode is the wave amplitude of sensed-mode.

There are four lateral support arm 2a-2d is total in the present embodiment, four lateral support arm 2a-2d are located at driven-mode radial direction At the node of vibration, shape is cuboid, and lateral support one end arm 2a-2d is fixed with disc-shape harmonic oscillator 1 in radial direction Connection, the other end is same, and there is the capacitance detecting electrode 4a-4d of displacement amplifying mechanism to fix.Capacitor inspection with displacement amplifying mechanism Electrode 4a-4d is surveyed by symmetrical two delta displacement enlarger 401a, 401b and two capacitor plates 402a, 402b Composition, delta displacement enlarger 401a, 401b are the isosceles trapezoidal structure without bottom, and two waists of isosceles trapezoid are elasticity Beam, upper bottom edge are buckstay, and the angle between two waist of isosceles trapezoid is obtuse angle.Delta displacement enlarger 401a, 401b's It is fixedly connected between upper bottom edge buckstay and capacitor plate 402a, 402b, capacitor plate 402a, 402b are parallel to delta displacement Two waist spring beams of the upper bottom edge buckstay of enlarger 401a, 401b, two delta displacement enlargers 401a, 401b are logical It crosses two and rigidly fixes beam connection.Capacitance detecting one end electrode 4a-4d with displacement amplifying mechanism is the same as lateral support arm 2a-2d It is fixedly connected, the other end is fixedly connected with detecting electrode fixing lug boss 5a-5d, and capacitor plate 402a, 402b and detecting electrode are solid Determine to be formed parallel capacitance gap between boss 2a-2d as detection capacitor.Capacitance detecting electrode with displacement amplifying mechanism There are four 4a-4d is total, the gap between capacitor plate 402a, 402b and detecting electrode fixing lug boss 5a-5d is 1-10 μm, is had The capacitance detecting electrode 4a-4d of displacement amplifying mechanism improves its conductivity by the technique that heavy ion adulterates.Disc-shape resonance It is provided with the through hole being symmetrically and evenly distributed about the center of circle on son 1, the rigidity of the big minor adjustment harmonic oscillator in change hole, circle can be passed through Disk shape harmonic oscillator 1 improves its conductivity by the technique that heavy ion adulterates.Arc-shaped driving electrodes 3a-3d and disc-shape are humorous Oscillator 1 with one heart, arc-shaped driving electrodes 3a-3d is located at the wave amplitude of 1 driven-mode of disc-shape harmonic oscillator, altogether there are four, justify Gap between arc driving electrodes 3a-3d and disc-shape harmonic oscillator 1 is 1-10 μm, and the depth-to-width ratio in gap is less than 20:1, circle Arc driving electrodes 3a-3d improves its conductivity by the technique that heavy ion adulterates.The outer diameter of detecting electrode fixing lug boss 5a-5d With one heart with disc-shape harmonic oscillator 1, detecting electrode fixing lug boss 5a-5d is located at the wave amplitude of 1 sensed-mode of disc-shape harmonic oscillator On corresponding radius extended line, altogether there are four, the outer diameter of detecting electrode fixing lug boss 5a-5d and arc-shaped driving electrodes 3a-3d Outer diameter size is identical.Substrate 6 is disc, and substrate 6 and disc-shape harmonic oscillator 1 are concentric, radius and detecting electrode fixing lug boss The outer diameter of 5a-5d and arc-shaped driving electrodes 3a-3d are identical, detecting electrode fixing lug boss 5a-5d and arc-shaped driving electrodes 3a-3d is fixed on substrate 6.Disc-shape harmonic oscillator 1, lateral support arm 2a-2d, the capacitance detecting with displacement amplifying mechanism Electrode 4a-4d, detecting electrode fixing lug boss 5a-5d, arc-shaped driving electrodes 3a-3d and substrate are all by<111>crystal orientation Silicon wafer on be made by micromechanics electronics processing technology.

Disc-shape harmonic oscillator 1 in the present embodiment, lateral support arm 2a-2d, arc-shaped driving electrodes 3a-3d have position Capacitance detecting the electrode 4a-4d, detecting electrode fixing lug boss 5a-5d and substrate 6 for moving enlarger are all by<111>crystal orientation Silicon wafer on be made by micromechanics electronics processing technology.It is first that Wafer Cleaning is clean, drying, then in front side of silicon wafer One layer photoresist of spin coating, photoetching development go out disc-shape harmonic oscillator 1, lateral support arm 2a-2d, arc-shaped driving electrodes 3a-3d And the corresponding region capacitance detecting electrode 4a-4d with displacement amplifying mechanism, ion implanting heavy doping is carried out, after annealing Remove photoresist；One layer of several microns of thick metallic aluminium are sputtered as exposure mask in silicon chip back side, in one layer photoresist of aluminium surface spin coating, Photoetching is carried out to photoresist using the mask plate made, is developed out except arc-shaped driving electrodes 3a-3d and detecting electrode are fixed The thickness of developing regional is thinned to disc-shape harmonic oscillator 1 using deep reaction ion etching by the region other than boss 5a-5d Thickness, remove aluminum mask；Using anode linkage technique by the back side of silicon wafer with together with the wafer bonding of substrate 6, use Substrate silicon wafer is thinned to required thickness by mechanical means；One layer of several microns of thick metallic aluminium are sputtered as exposure mask in front side of silicon wafer, In one layer photoresist of aluminium surface spin coating, photoetching is carried out to photoresist using the mask plate made, is developed out except disc-shape is humorous Oscillator 1, lateral bolster brace 2a-2d, arc-shaped driving electrodes 3a-3d, the capacitance detecting electrode 4a- with displacement amplifying mechanism Region other than 4d, detecting electrode fixing lug boss 5a-5d, discharges to obtain disc-shape harmonic oscillator using deep reaction ion etching 1, lateral bolster brace 2a-2d, arc-shaped driving electrodes 3a-3d, the capacitance detecting electrode 4a-4d with displacement amplifying mechanism and inspection Electrode fixing lug boss 5a-5d is surveyed, removes aluminum mask, it is micro- that radial support bulk acoustic wave silicon described in the present embodiment can be obtained in drying slice Gyroscope arrangement.

When applying the voltage drive signals with gyro driven-mode same frequency on arc-shaped driving electrodes 3a-3d, Under electrostatic force between driving electrodes 3a-3d and disc-shape harmonic oscillator 1, disc-shape harmonic oscillator 1 is generated as shown in Figure 4 Driven-mode under vibration, radial displacement is zero at lateral support arm under driven-mode vibration, therefore has displacement equations machine The capacitance detecting electrode 4a-4d of structure is without output；When there is the turning rate input of 1 axis direction of disc-shape harmonic oscillator, in Coriolis Power, which acts on lower gyro, can generate the vibration under sensed-mode as shown in Figure 5, under sensed-mode vibration at lateral support arm 2a-2d Radial displacement is maximum, and under the action of two delta displacement enlarger 401a, 401b, the thin tail sheep of sensed-mode exports quilt It is enlarged into the larger displacement output of capacitor plate 402a, 402b, the movement of capacitor plate 402a, 402b will lead to capacitor plate The variation of capacitor, the variable quantity of capacitor are proportional to input angular velocity between 402a, 402b and detecting electrode fixing lug boss 5a-5d Size can be detected input angular velocity by the size of measurement capacitance detecting electrode 4a-4d output.

The above is only a preferred embodiment of the present invention, protection scope of the present invention is not only limited to above-mentioned implementation Example, all technical solutions belonged under thinking of the present invention belong to protection category of the invention.It should be pointed out that for the art Technical staff for, several improvements and modifications without departing from the principles of the present invention, these improvements and modifications are also all answered It is considered as protection scope of the present invention.

Claims (4)

1. a radial support body acoustic wave silicon micro-gyroscope, it is characterized in that: comprise disc shape resonator, lateral support arm, have the capacitance detection electrode of displacement amplifying mechanism, detection electrode fixing boss, circular arc drive electrode and the substrate; the two in-plane four-amplitude node frequency matching modes of the disc-shaped resonator are used as the driving mode and the detection mode. The driving mode and the detection mode have the same mode shape, and their radial vibration is positive. Cross, that is, the amplitude of the driving mode is the node of the detection mode, and the node of the driving mode is the amplitude of the detection mode; there are four lateral support arms, and the four lateral support arms are located in the radial vibration of the driving mode. At the nodal point, the shape is a cuboid, one end of the lateral support arm is fixedly connected with the disc-shaped resonator in the radial direction, and the other end is fixed with the capacitance detection electrode with a displacement amplification mechanism; the capacitance detection electrode with a displacement amplification mechanism is symmetrical from left to right. It is composed of two triangular displacement amplifying mechanisms and two capacitor plates. The triangular displacement amplifying mechanism is an isosceles trapezoid structure with no lower base. The two waists of the isosceles trapezoid are elastic beams, the upper base is a rigid beam, and the isosceles trapezoid is The included angle between the two waists is an obtuse angle; the rigid beam on the upper base of the triangular displacement amplifying mechanism and the capacitor plate are fixedly connected, and the capacitor plate is parallel to the rigid beam on the upper and lower sides of the triangular displacement amplifying mechanism, and the two triangular displacement amplifying The elastic beams of the two waists of the mechanism are connected by two rigid fixed beams; one end of the capacitive detection electrode with the displacement amplification mechanism is fixedly connected with the lateral support arm, and the other end is fixedly connected with the fixed boss of the detection electrode, and the capacitive plate and the fixed convex of the detection electrode are fixedly connected. A parallel capacitance gap is formed between the stages as the detection capacitance; there are four capacitance detection electrodes with a displacement amplification mechanism, and the gap between the capacitance plate and the fixed boss of the detection electrode is 1-10 μm, and the capacitance detection electrode with a displacement amplification mechanism The electrical conductivity is improved by the process of heavy ion doping; the disc-shaped resonator is provided with through holes symmetrically and uniformly distributed about the center of the circle, and the stiffness of the resonator can be adjusted by changing the size of the hole. The ion doping process improves its electrical conductivity; the arc-shaped driving electrodes are concentric with the disc-shaped resonator, and the arc-shaped driving electrodes are located at the amplitude of the driving mode of the disc-shaped resonator, there are four in total, and the arc-shaped The gap between the driving electrode and the disc-shaped resonator is 1-10 μm, the aspect ratio of the gap is less than 20:1, and the electric conductivity of the circular-arc-shaped driving electrode is improved by heavy ion doping. 2. A kind of radial support body acoustic wave silicon micro-gyroscope based on claim 1, it is characterized in that: the outer diameter of the said detection electrode fixed boss is concentric with the disc-shaped resonator, and the detection electrode fixed boss is located in the circular There are four on the extension line of the radius corresponding to the amplitude of the detection mode of the disc-shaped resonator. 3. A kind of radial support body acoustic wave silicon micro-gyroscope based on claim 1, it is characterized in that: described base plate is disc shape, base plate and disc shape resonator are concentric, radius and detection electrode fixed boss and The outer diameters of the arc-shaped driving electrodes are the same, and the detection electrode fixing bosses and the arc-shaped driving electrodes are fixed on the base plate. 4. A radially supported bulk acoustic wave silicon micro-gyroscope according to claim 1, characterized in that: the disc-shaped resonator, the lateral support arm, the capacitance detection electrode with a displacement amplification mechanism, and the detection electrode is fixed The bosses, arc-shaped driving electrodes and substrates are all fabricated on a silicon wafer with &lt;111&gt; crystal orientation through a micro-machine electronic processing technology.