JPH07245416A - Acceleration detector and its manufacture - Google Patents

Abstract

PURPOSE:To form a sensor part and a circuit part in one piece on a high- resistance and single-crystal silicon substrate in an acceleration detector for improving sensitivity and miniaturize the detector. CONSTITUTION:A low-resistance region is formed at a high-resistance and single-crystal silicon substrate 32. A sensor part 34 is formed at the low- resistance region by etching treatment and a circuit part 42 which becomes a treatment circuit is formed at a high-resistance region. Then, a glass substrate 43 with a wiring pattern 44 for electrically connecting the circuit part 42 and the sensor part 34 is joined. thus arbitrarily setting the detection sensitivity of the sensor part 34 according to the size and depth of the low-resistance region and improving detection sensitivity. Also, the sensor part 34 is formed in one piece with the circuit part 42, thus miniaturizing the acceleration detector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration detecting device preferably used for detecting acceleration and a method of manufacturing the same, and more particularly to a sensor section for detecting acceleration and a circuit section for processing a detection signal from the sensor section. The present invention relates to an acceleration detecting device integrally formed with and a manufacturing method thereof.

[0002]

2. Description of the Related Art Generally, an acceleration sensor, which is a sensor section (acceleration detecting element) used to detect the acceleration and the rotation direction of a vehicle or the like, uses electrostatic capacitance between electrode plates to detect, for example, It is known from JP-A-3-94169 and JP-A-62-232171.

However, since these acceleration sensors have a small area (hereinafter referred to as "effective area") formed by the electrodes facing each other between the fixed portion and the movable portion, and the distance between them is large, the detection sensitivity becomes small and the accuracy is high. Could not detect the acceleration.

In order to improve such a drawback, in the acceleration sensor disclosed in Japanese Patent Laid-Open No. 4-115165, a fixed electrode and a movable electrode are provided with a comb-shaped electrode as a prior art.
The effective area between the electrodes is increased to improve the detection sensitivity.

An acceleration sensor according to the prior art is shown in FIG. 18 and will be described below.

In the figure, 1 is an acceleration sensor, 2 is a glass substrate as a square insulating substrate which is the base of the acceleration sensor 1, and is movable on the glass substrate 2 with fixed parts 3 and 3 described later. The part 5 is formed. Further, a rectangular concave groove 2A is formed on the upper surface of the glass substrate 2, and the concave groove 2A is formed.
The mass part 8 of the movable part 5 and the comb-shaped electrode 9 on the movable side located above.
Is displaceable in the direction of arrow A (direction in which acceleration is applied).

3 and 3 have low resistance (for example, a resistivity of 0.0
1 to 0.02 [Ωcm]) is a pair of fixing parts formed of a silicon material, and the fixing parts 3 are located on the left and right sides of the glass substrate 2 and are spaced apart from each other, and inner surfaces facing each other. Includes a plurality of (eg, three) thin electrode plates 4A, 4A.
.. are formed in a protruding manner, and each of the electrode plates 4A constitutes a fixed-side comb-shaped electrode 4, 4 as a fixed electrode.

Reference numeral 5 denotes a movable portion formed of a low-resistance silicon material, and the movable portion 5 is separated from the front and rear sides of the glass substrate 2 and is supported by the support portions 6 and 6 fixed to the glass substrate 2. A mass portion 8 supported by the supporting portions 6 via beams 7 and 7 and disposed between the fixing portions 3, and protruding from the mass portion 8 in the left and right directions, respectively. And a plurality of (for example, three) thin plate-shaped electrode plates 9A, 9A ,.
Is formed in a thin plate shape so that the mass portion 8 can be displaced in the direction of arrow A. Then, each movable side comb-shaped electrode 9
The respective electrode plates 9A of the above-mentioned are opposed to the respective electrode plates 4A of the above-mentioned fixed side comb-shaped electrodes 4 with a minute gap therebetween.

As described above, in the acceleration sensor 1 according to the prior art, the acceleration acting on the mass portion 8 is statically measured between the electrode plate 9A of the movable side comb-shaped electrode 9 and the electrode plate 4A of the fixed side comb-shaped electrode 4. The change in capacitance is detected as an electrical detection signal. Further, since the electrode plates 9A and 4A are electrically connected in parallel, the capacitances between the electrode plates 9A and 4A are added to each other, and the acceleration can be detected from the overall capacitance. The detection sensitivity can be increased and the acceleration detection accuracy can be improved.

Further, each fixing portion 3 of the acceleration sensor 1
The movable unit 5 and the movable unit 5 include a circuit that converts a detection signal output as a capacitance provided on another substrate into a voltage, an amplifier circuit that amplifies the converted voltage, a filter circuit that removes noise, and the like. The processing circuit is connected to a circuit via a lead wire or the like (none of which is shown), and the processing circuit converts a detection signal detected by the acceleration sensor 1 into a voltage signal.

As described above, in the acceleration sensor 1 according to the prior art, the processing circuit is mounted on another substrate, and the processing circuit and the acceleration sensor 1 are connected via a lead wire or the like. There is a problem that the stray capacitance of the line is superimposed on the detection signal, and accurate acceleration detection cannot be performed.

Further, when the acceleration sensor 1 and the substrate having the processing circuit are combined and integrated to form an acceleration detecting device, there is a problem that the substrate becomes large and the occupied area becomes large.

In order to solve this problem, as another conventional technique, as shown in FIGS. 19 and 20, it is made of low resistance polysilicon by using a film forming technique on a high resistance single crystal silicon substrate. There is known an acceleration detecting device in which a sensor part is formed and a circuit part is integrated by using a semiconductor manufacturing technique.

In the figure, 11 is an acceleration detecting device, and 12 is a rectangular high-resistance (for example, a resistivity of several [Ωcm]) single-crystal silicon substrate which is the base of the acceleration detecting device 11. A sensor unit 13 described later is provided on the substrate 12.
And a circuit portion 21 are formed.

Reference numeral 13 denotes a sensor portion formed on the silicon substrate 12 by a polysilicon film forming technique. The sensor portion 13 is a fixing portion 14 provided on the left and right sides of the silicon substrate 12 so as to be spaced apart from each other. 14 and a movable portion 16 which is located between the fixed portions 14 and extends in the front-rear direction. Each fixed portion 14 has a plurality of (for example, three) thin plate-shaped electrode plates on inner surfaces facing each other. 15A, 15A, ... (hereinafter,
As a whole, a "fixed-side comb-shaped electrode 15") is formed so as to project.

The movable portion 16 is provided with support portions 17 and 1 which are fixed to the front and rear sides of the silicon substrate 12 with a space therebetween.
7, and both supporting portions 17 are supported by the supporting portions 17 via beams 18.
A mass portion 19 arranged between the respective fixing portions 14, and a plurality of (for example, three) thin plate-shaped electrode plates 20A, 20A, ...
(Hereinafter, referred to as "movable side comb-shaped electrode 20" as a whole)
Consists of. The electrode plates 20A of the movable side comb-shaped electrodes 20 are the electrode plates 1 of the fixed side comb-shaped electrodes 15.
5A and 5A are opposed to each other with a minute gap therebetween.

Then, in order to displace each beam 18, mass portion 19 and movable side comb-shaped electrode 20 of the movable portion 16 in the direction of arrow A, as shown in FIG.
A gap S is formed between and. Therefore, in the manufacturing process of the sensor unit 13, the sacrificial layer is formed on the silicon substrate 1.
2 film deposition technology (eg low pressure CVD method)
The fixed portion 14 and the movable portion 16 made of polysilicon are formed by using the above method, and the sacrifice layer is removed by etching after that to form the gap S.

Further, reference numeral 21 denotes a circuit portion formed on the silicon substrate 12 using a semiconductor manufacturing technique, and the circuit portion 2
Reference numeral 1 is composed of a circuit for converting a detection signal output as electrostatic capacitance into a voltage, an amplifier circuit for amplifying the converted voltage, a filter circuit for removing noise, and the like.

Reference numerals 22, 22, 22 denote diffusion layers formed on the silicon substrate 12 so as to come into contact with the fixed portions 14 and the movable portion 16, respectively.
A conductive portion is formed on the silicon substrate 12 by doping boron in the case of a p-type semiconductor and arsenic, phosphorus in the case of a p-type semiconductor.

Reference numerals 23, 23, and 23 denote connecting members made of metal, and each connecting member 23 includes each diffusion layer 22 and the circuit portion 2.
1, which is connected to 1 and is formed in a thin plate shape with a material such as copper, aluminum, gold, or tungsten.

The surface of the silicon substrate 12 is covered with a SiO ₄ protective film (not shown).

In the acceleration detecting device 11 according to another prior art configured as described above, by using the high resistance silicon substrate 12, the circuit portion 21 can be easily formed by the semiconductor manufacturing technique, and the poly The sensor unit 13 can be manufactured by a silicon film forming technique, and the sensor unit 13 and the circuit unit 21 can be integrally formed.

Further, the operation of detecting the acceleration in the direction of arrow A is almost the same as that of the acceleration sensor 1 of the prior art described above, and the sensor portion 13 and the circuit portion 21 are integrated on the silicon substrate 12. By forming it, it is possible to prevent noise such as stray capacitance from being superimposed on the detection signal.

[0024]

By the way, in the acceleration detecting device 11 according to the above-mentioned other prior art, the sensor portion 13 and the circuit portion 21 are formed on the same silicon substrate 12, and the respective fixing portions of the sensor portion 13 are fixed. Since the portion 14 and the movable portion 16 are connected to the circuit portion 21 via the respective connecting members 23, the acceleration sensor 1 according to the prior art shown in FIG. 18 is connected to the processing circuit via the lead wire. Compared with the above, it is possible to prevent the superposition of noise due to the stray capacitance generated in the lead wire and the like, and the substrate is the silicon substrate 12.
Therefore, the area occupied by the acceleration detecting device 11 can be reduced. However, the other conventional techniques also have the following problems.

First, the thickness of the sensor portion 13 is several μm.
Since it is formed in a film shape, the weight of the mass portion 19 becomes light and the reaction to acceleration becomes slow.

Second, the area of each electrode plate 15A of the fixed-side comb-shaped electrode 15 and each electrode plate 20A of the movable-side comb-shaped electrode 20 becomes small, and the accuracy of acceleration detection in the sensor unit 13 decreases.

Thirdly, each beam 18 of the movable portion 16 needs to have a certain degree of strength in order to bend with the displacement of the mass portion 19 with respect to acceleration, but in the case of polysilicon, its Young's modulus is that of single crystal silicon. Since it is about 1/10 of that in comparison, it lacks reliability in terms of mechanical strength.

The present invention has been made in view of the problems of the above-described conventional technique and other conventional techniques. The sensor unit and the circuit unit serving as a processing circuit can be integrally formed with a single crystal silicon substrate, and highly accurate acceleration is achieved. An object of the present invention is to provide an acceleration detecting device capable of detecting and a manufacturing method thereof.

[0029]

An acceleration detecting device according to a first aspect of the present invention is a high-resistance single crystal silicon substrate having a low resistance region formed therein, and a sensor portion formed in the low resistance region of the silicon substrate. In order to connect the circuit portion formed in the high resistance region of the silicon substrate, the insulating substrate fixedly provided to the silicon substrate, the sensor portion and the circuit portion,
And the wiring pattern provided on the insulating substrate.

According to a second aspect of the present invention, the sensor portion includes a fixed portion and a movable portion which are formed separately from each other by etching a low resistance region formed on one side of the silicon substrate. A fixed electrode is formed integrally with the fixed part, and the movable part is connected to the support part fixed to the insulating substrate and the support part via a beam so that the movable part responds to the acceleration when the acceleration acts. From a movable electrode that is provided so as to face a fixed electrode formed on the fixed portion with a minute gap between the movable portion and the movable portion that moves close to and away from the fixed portion. It can be formed integrally.

In this case, as in the third aspect, the fixed electrode and the movable electrode of the sensor section can be comb-shaped electrodes facing each other with a minute gap therebetween.

Further, it is preferable that a cover for covering the sensor portion is provided on the silicon substrate.

On the other hand, a method of manufacturing an acceleration detecting device according to a fifth aspect comprises a low resistance region forming step of forming a low resistance region on one side surface of a high resistance single crystal silicon substrate, and a high resistance region of the silicon substrate. A circuit portion forming step of forming a circuit portion by a semiconductor manufacturing technique, a groove portion forming step of forming a groove portion in a low resistance region of the silicon substrate by an etching process, and an insulating substrate having a wiring pattern of a silicon substrate in which the groove portion is formed. A joining step of joining to one side surface, and a sensor section forming step of forming a sensor section by performing etching processing from the other side surface of the silicon substrate and separating the fixed section and the movable section by the groove section formed in the silicon substrate. Consists of.

[0034]

In the acceleration detecting device according to the present invention, the low resistance region is formed in a part of the high resistance silicon substrate, the sensor portion is formed in the low resistance region, and the circuit is formed in the high resistance region. Thus, the sensor portion and the circuit portion can be formed on the same silicon substrate, and the strength of the sensor portion can be improved by forming the sensor portion from single crystal silicon. Furthermore, the detection sensitivity of the sensor unit can be adjusted by arbitrarily selecting the size and depth of the low resistance region.

Further, according to the second aspect, since the sensor portion including the fixed portion and the movable portion is formed in the low resistance region of the silicon substrate, the acceleration is detected as the displacement of the mass portion, and the fixed electrode and the movable electrode are detected. Since the proximity and the separation of the sensor are detected as a change in capacitance, and the sensor portion is formed of single crystal silicon, the strength of the sensor portion can be improved.

Further, in the third aspect, the fixed electrode and the movable electrode of the sensor section are formed as comb-shaped electrodes facing each other, thereby increasing the effective area between the fixed electrode and the movable electrode.

Further, in the present invention, by covering the fixed part and the movable part of the sensor part with a cover, it is possible to prevent dust and the like from entering the fixed part and the movable part of the sensor part which are the parts for detecting acceleration. To do.

On the other hand, according to the method for manufacturing an acceleration detecting device of the fifth aspect, the low resistance region is formed in the low resistance region forming step, and the semiconductor manufacturing technique is used in the circuit part forming step. Utilizing this, a circuit portion is formed in the high resistance region of the silicon substrate, a groove portion for forming a fixed portion and a movable portion of the sensor portion is formed in the low resistance region in the groove portion forming step, and a silicon portion is formed in the joining step. One side surface of the substrate is joined to the insulating substrate, and in the sensor section forming step, the other side surface of the silicon substrate is subjected to etching treatment to separately form the fixed section and the movable section on the silicon substrate to form the sensor section.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In the embodiments, the same components as those shown in FIGS. 18 to 20 according to the above-described conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

First, FIGS. 1 to 13 show a first embodiment.

In the figure, reference numeral 31 denotes an acceleration detecting device according to this embodiment. The acceleration detecting device 31 includes a high-resistance single crystal silicon substrate 32 described later and a sensor portion formed on one of the silicon substrates 32. 34 and the silicon substrate 32
Circuit part 42 formed on one side of the silicon substrate 3
The glass substrate 43 is bonded to one side surface of the second substrate 2.

Reference numeral 32 denotes a silicon substrate, and the silicon substrate 32 is formed in a rectangular shape by a high resistance single crystal having a resistivity of several [Ωcm], for example. Further, on one side of the silicon substrate 32, as shown in FIG. 4, a low resistance region 33 is formed from one side surface to the other side surface by a low resistance region forming step described later.

Reference numeral 34 denotes a sensor portion according to this embodiment. The sensor portion 34 is a fixing portion 35 formed by etching the low resistance region 33 in the silicon substrate 32 in a sensor portion forming step described later. 35 and movable part 3
It is composed of 7.

Denoted at 35 and 35 are fixed portions located on the left and right sides, and each of the fixed portions 35 has thin plate-like electrode plates 36A, 36A, ... A fixed-side comb-shaped electrode 36 having a is formed.

Reference numeral 37 denotes a movable portion, which is
The support portions 38, 38 located on the upper and lower sides and the respective support portions 3
8 is supported on both sides via beams 39, 39, and is formed so as to protrude from the mass portion 40 disposed between the fixed portions 35 and the fixed side comb-shaped electrodes 36. The movable-side comb-shaped electrode 41 has thin plate-shaped electrode plates 41A, 41A, ...

Reference numeral 42 denotes a circuit portion, which is formed in a high resistance region (a region other than the low resistance region 33) of the silicon substrate 32 by a semiconductor manufacturing technique by a circuit portion forming process described later. ing. Further, the circuit section 42 is specifically, a conversion circuit for converting the detection signal as the electrostatic capacitance from the sensor section 34 into a voltage signal, an amplification circuit for amplifying the converted voltage, and a filter circuit for removing noise. And the like.

Reference numeral 43 denotes a glass substrate as an insulating substrate which is bonded to one side surface of the silicon substrate 32 and is formed in a rectangular shape shorter than the silicon substrate 32.
3 has a recessed groove 43 as shown in FIGS. 2, 9 and 10.
A is formed, and the beams 39, the mass parts 40, and the electrode plates 36A and 41A are formed by the concave groove 43A.
And the mass portion 40 is movable in the direction of arrow A. Further, as shown in FIG. 10, wiring patterns 44, 44, 44 made of a metal material (gold, aluminum, copper, tungsten, etc.) are formed on the surface of the glass substrate 43, and each wiring pattern 44 is fixed. The section 35, the movable section 37, and the circuit section 42 are electrically connected to each other. Also, 45, 45, ...
It is an extraction electrode that leads the signal from 2 to the outside.

The acceleration detecting device 31 according to the present embodiment has the above-described structure. Next, a method of manufacturing the acceleration detecting device 31 will be described with reference to FIGS.

First, FIG. 3 shows a masking step which is a preparatory step before the low resistance region forming step. The masking step is a silicon substrate 3 formed of high resistance single crystal silicon.
The protective film 51 made of a silicon oxide film is formed on one side surface of No. 2 except the low resistance region 33.

In the low resistance region forming step shown in FIG. 4, impurities are introduced into the silicon substrate 32 by a thermal diffusion method, an ion implantation method or the like to form the low resistance region 33.

That is, if the silicon substrate 32 is n-type, B
By introducing (boron), the low resistance region 33 becomes p
Type silicon, and if the silicon substrate 32 is p-type silicon, by introducing P (phosphorus) and As (arsenic),
The low resistance region 33 becomes n-type silicon.

Next, FIG. 5 shows a masking step which is a preparatory step before the circuit section forming step. In the masking step, the low resistance region 33 is not destroyed during the circuit section forming step after the protective film 51 is removed. Circuit section 4
The portion other than 2 (see FIG. 6) is a protective film 5 made of a thermal oxide film.
Cover with 2.

In the circuit portion forming step shown in FIG. 6, the circuit portion 42 is formed in the high resistance portion of the silicon substrate 32 by using a semiconductor manufacturing technique.

Here, the semiconductor manufacturing technique of the circuit portion 42 will be described. Thermal oxidation treatment, thermal diffusion treatment, ion implantation treatment,
It is a process of manufacturing through photo etching processing, wet etching, dry etching processing, CVD method and the like. As a result, the circuit section 42 of C-MOS or the like is formed. In addition,
The surface of the circuit portion 42 has a connection terminal 42 indicated by a dotted line in FIG.
A portion other than A, 42A, 42A and extraction electrodes 45, 45, ... Protective film made of plasma nitride film (not shown)
Is covered with.

Next, FIG. 7 shows a masking step which is a preparatory step before the groove forming step. In the masking step, after the protective film 52 is removed, one surface of the silicon substrate 32 is entirely covered with an oxide film (or a nitride film). Of the protective film 53 and the photoresist 54, and the groove 55 (see FIG. 8) for separately forming the fixed portion 35 and the movable portion 37 is formed in the protective film 53 and the photoresist. 54 is removed by photoetching.

In the groove forming step shown in FIG. 8, after removing the photoresist 54, anisotropic etching is performed to form the groove 55 in the low resistance region 33. When the surface orientation of one side surface of the silicon substrate 32 is the (110) plane, wet etching can also be used.

Next, in the bonding step shown in FIGS. 9 and 10, the protective film 53 on the silicon substrate 32 is removed, and the recessed grooves 43A and the wiring patterns 4 formed in advance in another step.
The glass substrate 43 having No. 4 is bonded to the silicon substrate 32 by anodic bonding and integrally formed as shown in FIG. At this time, one of the wiring patterns 44 is connected to the circuit portion 42.
On the other side, the fixed portion 35, 35 and the support portion 38 of the movable portion 37 are provided on the other side.
It is designed to be electrically connected to. Further, since each extraction electrode 45 of the circuit section 42 is not covered with the glass substrate 43, each extraction electrode 45 is not
The signal from 2 is derived to the outside. Furthermore, the concave portion 43A of the glass substrate 43 prevents the beams 39, the mass portion 40, and the movable comb-shaped electrode 41 of the movable portion 37 from coming into contact with the glass substrate 43, and the mass portion 40 is displaced in the arrow A direction. It is possible.

Further, in the step of forming the sensor portion shown in FIG. 12, dry etching is performed from the other side surface of the silicon substrate 32 in order to remove the portion indicated by the chain double-dashed line in FIG.
This etching is performed until the groove 55 formed in the low resistance region 33 penetrates. Thus, the sensor portion 34 is formed on the silicon substrate 32 by removing the portion indicated by the alternate long and two short dashes line. At this time, of the sensor unit 34, each fixing unit 3
5. The supporting portions 38 of the movable portion 37 are already integrated because they are fixed to the glass substrate 43 in the above-described joining process.

The acceleration detecting device 31 according to the present embodiment is constructed as described above, and there is no difference in the acceleration detecting operation from the prior art, and when the mass portion 40 is displaced in the arrow A direction by the acceleration, Displacement of each electrode plate 36A,
41A is detected as a change in capacitance, and the detection signal is derived from the sensor unit 34 to the circuit unit 42 via each wiring pattern 44. In the circuit unit 42, a signal based on the capacitance from the sensor unit 34 is output. Is converted into a voltage signal and output to the outside.

Further, as a reference diagram in FIG. 13, a mounting groove 56A is formed in the mounting board 56 to show the mounting state of the acceleration detecting device 31, and the mounting groove is fixed on the mounting board 56 with an adhesive or the like. 56A prevents the fixed portion 35 and the movable portion 37 of the sensor portion 34 from coming into contact with the mounting substrate 56, so that the mass portion 40 is in the detection direction (the arrow A direction).
Will be displaced.

Therefore, the acceleration detecting device 3 according to the present embodiment.
In No. 1, the sensor unit 34 for detecting acceleration can be formed of the single crystal silicon substrate 32, and the thickness dimension of the sensor unit 34 can be set to several tens of μm.
By increasing the effective area between A, the detection sensitivity can be improved.

Further, since the silicon substrate 32 is formed of high-resistance single crystal silicon, a semiconductor manufacturing technique can be used for forming the circuit portion 42.
In forming the sensor section 34, an etching process of silicon can be used, and the circuit section 42 and the sensor section 34 can be formed on a single silicon substrate 32. As a result, it is not necessary to provide the sensor section 34 and the circuit section 42 on different substrates, and the acceleration detection device 31 can be formed compactly. Then, the acceleration detection device 31
Can occupy a small area and can be grounded even in a narrow space.

Further, by setting the size and depth of the low resistance region 33 formed on the high resistance silicon substrate 32 arbitrarily, when the low resistance region 33 is large or deep, the fixed side of the sensor portion 34 is fixed. By increasing the sizes of the comb-shaped electrode 36 and the movable-side comb-shaped electrode 41, the effective area can be increased and the detection sensitivity from the sensor unit 34 can be improved. On the contrary, when the detection sensitivity is reduced, the low resistance region 33 is formed narrowly or shallowly to form the sensor section 34, so that the fixed side comb-shaped electrode 36 and the movable side comb-shaped electrode 41 of the sensor section 34 are formed. The effective area can be reduced, and the detection sensitivity can be reduced. in this way,
It is also possible to adjust the sensor sensitivity of the sensor unit 34 according to the acceleration to be detected.

On the other hand, by forming the sensor portion 34 from a silicon single crystal, the strength of the sensor portion 34 (in particular, the strength of each beam 39) can be increased, and the sensor portion 34 can be increased.
The life of can be extended.

Further, since the circuit portion 42 and the sensor portion 34 are connected by the respective wiring patterns 44 provided on the glass substrate 43 joined to the silicon substrate 32, the connection by the lead wire or the like can be eliminated. The generation of noise due to the vibration of each lead wire can be eliminated, noise can be prevented from being superimposed on the detection signal between the sensor unit 34 and the circuit unit 42, and highly accurate acceleration detection can be performed.

If the grounding position of the acceleration detecting device 31 according to the first embodiment is a place where dust or the like is less likely to occur, the glass substrate 43 may be grounded.
It is not necessary to form the concave groove 56A in the mounting substrate 56 as described above.

Next, FIGS. 14 to 16 show a second embodiment according to the present invention. The feature of the acceleration detecting device 61 according to the present embodiment is that the acceleration detecting device 31 according to the first embodiment described above is different. This is because a cover 62 that covers the sensor unit 34 is provided. In this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals,
The description is omitted.

In the figure, reference numeral 61 denotes an acceleration detecting device according to the present embodiment, and the acceleration detecting device 61 is provided with a cover 62 described later on the other side surface of the silicon substrate 32 of the acceleration detecting device 31 of the first embodiment. It is a thing.

Reference numeral 62 denotes a cover provided on the other side surface of the silicon substrate 32. The cover 62 is made of an insulating material such as glass, and as shown in FIG.
2A is formed. The concave groove 62A prevents the cover 62 from contacting the fixed portion 35 and the movable portion 37 of the sensor portion 34.

Further, as shown in FIG. 16, the above-mentioned first
In the embodiment of the above, after the sensor portion forming step shown in FIG.
By performing the cover bonding process in which the cover 62 is provided on the other side surface of the silicon substrate 32 by using anodic bonding, the acceleration detecting device 61 according to the present embodiment can be easily formed.

Although the acceleration detecting device 61 according to the present embodiment is constructed in this way, the operation and effect thereof are substantially the same as those of the first embodiment. Furthermore, in the acceleration detecting device 61 according to the present embodiment, the sensor By providing the cover 62 covering the portion 34 on the silicon substrate 32, it is possible to reliably prevent dust and the like from entering between the fixed portion 35 and the movable portion 37, and effectively extend the life of the sensor portion 34. You can

In the second embodiment, the cover 62
The plate is made of a glass material in the form of a plate, but is not limited to this and may be made of a ceramic material, a resin material, or the like. In this case, the silicon substrate 32 may be provided with an adhesive or the like.

Further, FIG. 17 shows a third embodiment according to the present invention. The feature of this embodiment is that the movable portion in the sensor portion of the acceleration detecting device is supported by a cantilever. In the present embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. Only the characteristic part of the present embodiment will be described.

In the figure, reference numeral 71 denotes a sensor portion according to the present embodiment, which is formed in place of the sensor portion 34 used in the above-mentioned first embodiment, and the sensor portion 71 has a high resistance. Between the fixed portions 73, 73 located on the left and right sides and the respective fixed portions 73, which are formed in the low resistance region of the crystalline silicon substrate 72 by substantially the same manufacturing process as that of the first embodiment described above. And a movable part 74 located at. The movable part 74 is composed of a support part 75 fixed to the glass substrate 43 and a mass part 77 provided from the support part 75 via a beam 76, and the side surfaces of the fixed parts 73 are fixed electrodes 74A. And the side surface of the mass portion 77 is the movable electrode 77.
It is A.

Reference numeral 78 denotes a cover, which is formed of an insulating material such as glass or silicon into a plate shape having a groove 78A. The cover 78 covers the sensor portion 71 and the other surface of the silicon substrate 32. It is provided on the side.

Reference numeral 79 denotes a circuit portion formed outside the sensor portion 71 of the silicon substrate 72 by a semiconductor manufacturing technique. The circuit portion 79 is similar to the circuit portion 42 according to the first embodiment. The detection signal is converted into a voltage signal. Further, 80, 80, ...
It is an extraction electrode that leads the signal from 9 to the outside.

Even in the acceleration detecting device according to the present embodiment having the above-mentioned structure, the function and effect are the same.

Although the glass substrate 43 is used as the insulating substrate in each of the above-described embodiments, the present invention is not limited to this, and an insulating material such as ceramic or resin material may be used.

In addition, in the third embodiment, the second
Although the cover 78 is provided in the same manner as in the first embodiment, the present invention is not limited to this, and the cover 78 may be removed and used similarly to the acceleration detecting device 31 according to the first embodiment. Of course.

Further, in each of the above embodiments, the circuit portion 42 (79) and the sensor portion 34 (71) are formed on the silicon substrate 32 by the semiconductor manufacturing technique and the silicon etching technique. However, it is needless to say that the silicon substrate 32 may be formed using a silicon wafer.

Furthermore, in each of the above-described embodiments, the glass substrate 43 is made smaller than the silicon substrate 32 (72) to form the extraction electrodes 45, 45, ... Which lead the signal from the circuit section 42 to the outside. However, the present invention is not limited to this, and the glass substrate 43 is replaced by the silicon substrate 32 (7).
The extraction electrode may be formed to be larger than that in 2) and the extraction electrode may be formed on the glass substrate 43 side, and the signal from the circuit unit 42 may be extracted to the outside by the extraction electrode.

[0082]

In the acceleration detecting device according to the first aspect of the present invention, the sensor section and the circuit section are formed on the same silicon substrate, and the sensor section and the circuit section are electrically formed by the wiring pattern formed on the insulating substrate. Since the connection is made, the low resistance region is formed in a part of the high resistance silicon substrate, the sensor portion is formed in the low resistance region, and the circuit is formed in the high resistance region. The sensor part can be formed on the same silicon substrate, and the strength of the sensor part can be improved by forming the sensor part from single crystal silicon. Further, the detection sensitivity of the sensor unit can be adjusted by arbitrarily selecting the size and depth of the low resistance region, and the detection sensitivity can be set arbitrarily.

Further, in the acceleration detecting device according to the second aspect of the present invention, the sensor portion including the fixed portion and the movable portion is formed by etching silicon in the low resistance region of the single crystal silicon substrate, and the mass portion of the movable portion is formed. Since the displacement and the proximity of the movable electrode of the mass portion and the fixed electrode of the fixed portion are detected as a change in electrostatic capacitance, the distance between the fixed electrode and the movable electrode is reduced to reduce the distance between each electrode. The effective area can be increased, and the detection sensitivity of the sensor unit can be improved. Furthermore, the strength of the sensor portion can be improved by forming the sensor portion in single crystal silicon.

Further, as in the invention of claim 3, since the fixed electrode and the movable electrode of the sensor section are comb-shaped electrodes,
The effective area between the electrodes can be increased, and the acceleration detection sensitivity can be improved.

Furthermore, as in the invention of claim 4, by forming a cover for covering the fixed part and the movable part in the sensor part, it is possible to prevent dust and the like from entering between the electrodes, and to accelerate the acceleration. The life of the detection device can be extended.

On the other hand, in the method of manufacturing the acceleration detecting device according to the fifth aspect, the high resistance single crystal silicon substrate is used to form the low resistance region in the silicon substrate in the low resistance region forming step, and in the circuit part forming step. A circuit portion is formed in a high resistance region of the silicon substrate, a groove portion for forming a fixed portion and a movable portion of the sensor portion is formed in the low resistance region in the groove portion forming step, and a wiring is formed in the silicon substrate in the joining step. An insulating substrate having a pattern is joined to electrically connect the sensor unit and the circuit unit, and in the sensor unit forming step, an etching process is performed from the other side surface of the silicon substrate to provide a fixed unit and a movable unit on the silicon substrate. By separately forming, the thickness of the fixed portion and the movable portion of the sensor portion can be increased, and the detection sensitivity can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a partially broken glass substrate of an acceleration detecting device according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view as seen from the direction of arrows II-II in FIG.

FIG. 3 is a vertical cross-sectional view showing a state in which a masking process is performed as a preliminary process in preparation for a low resistance region forming process on a high resistance single crystal silicon substrate in the manufacturing process of the acceleration detecting device.

FIG. 4 is a vertical cross-sectional view showing a state in which a low resistance region is formed on a silicon substrate by a low resistance region forming step.

FIG. 5 is a vertical cross-sectional view showing a state in which a masking process is performed as a preliminary process to prepare for the circuit portion forming process.

FIG. 6 is a vertical cross-sectional view showing a state in which a circuit portion is formed on a silicon substrate by a circuit portion forming step.

FIG. 7 is a vertical cross-sectional view of a silicon substrate in a state where a masking process is performed as a preliminary process for the groove forming process.

FIG. 8 is a vertical cross-sectional view showing a state in which a groove portion for forming a fixed portion and a movable portion is formed in a low resistance region of a silicon substrate by a groove portion forming step.

FIG. 9 is a vertical cross-sectional view showing a joining step of joining a silicon substrate and a glass substrate.

10 is a perspective view showing a step of joining a silicon substrate and a glass substrate according to FIG.

FIG. 11 is a vertical cross-sectional view showing a state in which a silicon substrate and a glass substrate are bonded by a bonding process.

FIG. 12 is a vertical cross-sectional view showing a state in which a fixed portion and a movable portion of the sensor unit are formed by etching the silicon substrate in the sensor unit forming step.

FIG. 13 is a perspective view showing a state in which the acceleration detecting device according to the first embodiment is mounted on a mounting board.

FIG. 14 is a perspective view showing a broken glass substrate of an acceleration detecting device according to a second embodiment of the present invention.

15 is a vertical cross-sectional view as seen from the direction of arrows XV-XV in FIG.

FIG. 16 is a vertical cross-sectional view showing a cover joining process subsequent to the sensor portion forming process.

FIG. 17 is a perspective view showing a state in which a silicon substrate and a glass substrate showing an acceleration sensor according to a third embodiment of the present invention are separated.

FIG. 18 is a perspective view showing a conventional acceleration sensor.

FIG. 19 is a perspective view showing an acceleration sensor according to another conventional technique.

FIG. 20 is a vertical cross-sectional view taken along the line XX-XX in FIG.

[Explanation of symbols]

 31, 61 Acceleration detection device 32, 72 Silicon substrate 33 Low resistance region 34, 71 Sensor part 35, 73 Fixed part 36 Fixed side comb-shaped electrode (fixed electrode) 37, 74 Movable part 38, 75 Support part 39, 76 Beam 40 , 77 mass part 41 movable side comb-shaped electrode (movable electrode) 42, 79 circuit part 43 glass substrate (insulating substrate) 44 wiring pattern 55 groove part 74A fixed electrode 77A movable electrode

Claims (5)

[Claims] 1. A high resistance single crystal silicon substrate having a low resistance region formed therein, a sensor portion formed in the low resistance region of the silicon substrate, and a circuit portion formed in the high resistance region of the silicon substrate. And an insulating substrate fixed to the silicon substrate and a wiring pattern provided on the insulating substrate for connecting the sensor unit and the circuit unit. 2. The sensor part includes a fixed part and a movable part which are formed separately from each other by etching a low resistance region formed on one side of the silicon substrate,
A fixed electrode is formed integrally with the fixed portion, and the movable portion is connected to the support portion fixed to the insulating substrate and the support portion via a beam so that the movable portion responds to the acceleration when an acceleration is applied. Between the movable mass electrode and the movable electrode, which is provided so as to face the fixed electrode formed on the fixed portion with a small gap between the movable mass electrode and the movable electrode that moves close to and away from each other by the displacement of the mass portion. An acceleration detection device formed integrally. 3. The fixed electrode and the movable electrode of the sensor section are
The acceleration detection device according to claim 1, wherein the acceleration detection devices are comb-shaped electrodes facing each other with a minute gap therebetween. 4. The acceleration detection device according to claim 1, wherein the silicon substrate is provided with a cover that covers the sensor unit. 5. A low resistance region forming step of forming a low resistance region on one side surface of a high resistance single crystal silicon substrate, and a circuit portion formation of forming a circuit unit in the high resistance region of the silicon substrate by a semiconductor manufacturing technique. A step, a groove forming step of forming a groove in the low resistance region of the silicon substrate by an etching process, and a joining step of joining an insulating substrate having a wiring pattern to one side surface of the silicon substrate in which the groove is formed,
Etching is performed from the other side of the silicon substrate,
A method of manufacturing an acceleration detecting device, comprising: a sensor section forming step of forming a sensor section by separating a fixed section and a movable section by a groove section formed in the silicon substrate.