JP2002071707A - Semiconductor dynamic quantity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize changes in the detection interval between a mobile electrode and fixed electrodes attributed to a temperature change in a semiconductor dynamic quantity sensor for detecting an applied dynamic quantity, based on the changes in the detection interval between the mobile and the fixed electrodes each comprising a semiconductor supported on a support base board. SOLUTION: A rectangular opening part 21 is formed in a support base board 20 being opened on one side thereof, and a mobile electrode 30 and fixed electrodes 40 and 50 are supported at a rim facing the opening part 21. The direction of isolating two supports 34a and 34b facing each other at the mobile electrode 30 is made almost the same as the direction of isolating two supports 41a and 41b and those 51a and 51b respectively facing each other at the fixed electrodes 40 and 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a beam structure comprising a semiconductor having a movable electrode and a fixed electrode formed on a support substrate, and a change in the distance between the movable electrode and the fixed electrode. The present invention relates to a semiconductor dynamic quantity sensor that detects an applied dynamic quantity based on, and can be applied to, for example, an acceleration sensor or an angular velocity sensor.

[0002]

2. Description of the Related Art As a semiconductor dynamic quantity sensor of this kind,
For example, one disclosed in Japanese Patent Application Laid-Open No. H11-326365 has been proposed. FIG. 7 shows a general configuration diagram of this type of semiconductor dynamic quantity sensor. Here, in FIG.
(A) is a schematic plan view, (b) is BB sectional drawing in (a).

[0003] As shown in FIG.
It is formed by subjecting a semiconductor substrate having an insulating layer 203 between the semiconductor layer 201 and the second semiconductor layer 202 to a known micromachining utilizing a semiconductor manufacturing technique. Here, for example, the two semiconductor layers 201 and 202 are made of silicon (Si), and the insulating layer 203 is made of a Si oxide film.

[0004] By forming a groove in the second semiconductor layer 202 of the semiconductor substrate, a movable electrode 204 that is displaced in response to the application of a mechanical quantity, and a detection interval 206 between the movable electrode 204 and the movable electrode 204.
, And a beam structure including the opposing fixed electrode 205 is formed. In the illustrated example, both electrodes 204, 205
The movable electrode 204 includes a weight portion 207 and a rod-shaped portion 208 protruding from the weight portion 207. The fixed electrode 205 has a side surface of the rod-shaped portion 208 of the movable electrode 205.
Bar 209 facing each other with a detection interval 206 on the side surface of
It has.

Here, a support substrate is formed by the first semiconductor layer 201 and the insulating layer 203, and the support substrate has an opening 210 formed on the surface on the second semiconductor layer 202 side. In the illustrated example, the first in the support substrate
A rectangular opening 210 is formed to penetrate both layers of the semiconductor layer 201 and the insulating layer 203 in the thickness direction.

[0006] Both ends of the weight portion 207 are elastically supported and fixed at a pair of opposing sides of the edge of the opening 210, and the movable electrode 204 is applied on the opening 210 with a dynamic force applied thereto. Arrow X in FIG. 7A according to the amount (acceleration, etc.)
It is displaced in the direction. In addition, the fixed electrode 20
5 support portion 211 is one of the edges of the opening portion 210.
The other side of the set different from the side of the set is supported and fixed to the support substrate.

In the semiconductor dynamic quantity sensor, when the movable electrode 204 is displaced in response to the application of the dynamic quantity, the detection interval is set to two.
The applied dynamic quantity is detected on the basis of the change of 06. For example, the detection interval 206 on the left side in FIG.
Is the first detection capacitance CS1 and the capacitance formed in the right detection interval 206 is the second detection capacitance CS2, the detection interval 206, that is, the displacement of the movable electrode 204 due to the applied physical quantity. Each of the detection capacitors CS1 and CS2 changes, and by detecting this as a difference between the two detection capacitors CS1 and CS2 (differential detection), the applied dynamic quantity can be detected.

[0008]

However, according to the study by the present inventors, in this type of sensor, when the operating temperature changes, the heat of each part of the support substrates 201 and 203 and the beam structures 204 and 205 is reduced. It has been found that there is a problem that the temperature characteristics are deteriorated because the respective portions are deformed due to the difference in expansion coefficient, and the detection interval 206 between the movable electrode and the fixed electrode is changed by extending or contracting.

In particular, as shown in FIG. 7B, in this type of sensor, the supporting substrates 201 and 203 have a lower thermal expansion coefficient on the lower side (on the first semiconductor layer 201 side) than the supporting substrate. The package 21 is joined to a large package 212 made of, for example, ceramic (for example, alumina or the like).
2 are bonded and fixed via an adhesive (for example, polyimide resin) 213.

[0010] For this reason, due to the difference in thermal expansion between Si, the Si oxide film, the adhesive, and the package, the deformation as shown in (c) and (d) in FIG. 7 occurs. For example, when the temperature is changed from room temperature to low temperature, the ceramic package 212 under the support substrate is used.
Of the support substrate 201,
203 is deformed so as to be convex toward the insulating layer 203 (see FIG. 7D). Such a convex deformation of the support substrate occurs along the arrow X direction in FIG. 7A and a direction orthogonal to the X direction.

In this case, the movable electrode 204 corresponds to the arrow X
In contrast to the movable electrode 204, the fixed electrode 205 deforms in a fan shape while being deformed so as to extend along the direction. That is, as shown in FIG.
Is a rod-shaped part 209a on one end side (upper side in the figure) of the rod-shaped parts 209 of the fixed electrode located at both ends in the arrow X direction.
At the other end (the lower side in the figure) of the rod-shaped portion 209.
It stretches at b.

As described above, in a conventional semiconductor dynamic quantity sensor, a movable electrode, a fixed electrode, a support substrate, and
The movable electrode and the fixed electrode undergo deformation due to a temperature change due to the difference in the thermal expansion coefficients of the constituent materials of the package and the like in which the sensor is provided. However, the deformation method differs between the movable electrode and the fixed electrode. The gap is displaced.

In view of the above problems, the present invention has a support substrate, a movable electrode and a fixed electrode made of a semiconductor supported on the support substrate, and based on a change in a detection interval between the movable and fixed electrodes. An object of the present invention is to minimize a change in a detection interval between a movable electrode and a fixed electrode due to a temperature change in a semiconductor dynamic quantity sensor configured to detect an applied dynamic quantity.

[0014]

According to the present invention, the deformation of the movable electrode and the fixed electrode due to the above-mentioned temperature change is caused by receiving a stress from a support portion of the electrode to the supporting substrate and causing a deformation in the direction of the stress. Accordingly, the arrangement of the electrode support is devised so that the deformation direction of the movable electrode and the fixed electrode is made to be the same direction as much as possible.

That is, according to the first aspect of the present invention, the support substrate (20) in which the opening (21) opening on one side is formed.
A movable electrode (30) made of a semiconductor supported by the support substrate and displaced on the opening in response to the application of a mechanical quantity;
A fixed electrode (4) made of a semiconductor supported by the support substrate and opposed to the movable electrode on the opening with a detection interval (60).
0, 50), wherein the movable electrode is displaced in response to the application of the dynamic quantity, and the applied dynamic quantity is detected based on a change in the detection interval. 34a, 34b) and the support portions (41a, 41b, 51a, 51b) of the fixed electrode to the support substrate are respectively located at both edges of the opposing opening, and the direction in which the two support portions of the movable electrode are separated from each other is fixed. It is characterized in that the direction separating the two support portions in the electrode is substantially the same.

According to the present invention, since both support portions of the movable electrode and both support portions of the fixed electrode are separated in substantially the same direction with the opening therebetween, the stress applied from the support portion due to the deformation of the support substrate. Are substantially the same for the movable electrode and the fixed electrode. That is, even if a temperature change occurs, the movable electrode and the fixed electrode deform so as to extend and contract in substantially the same direction between the respective support portions.

Therefore, the direction of the deformation of the movable electrode due to the temperature change is substantially the same as the direction of the deformation of the fixed electrode. As a result, according to the present invention, the detection interval between the movable electrode and the fixed electrode due to the temperature change is reduced. The change can be suppressed as much as possible.

Further, according to the second aspect of the present invention, the axis connecting the two support portions (34a, 34b) of the movable electrode (30) and the two support portions (41) of the fixed electrode (40, 50) are provided.
a, 41b, 51a, 51b) are parallel to an axis connecting them.

According to this, since the direction of the stress applied from the supporting portion due to the deformation of the supporting substrate can be made to coincide between the movable electrode and the fixed electrode, the effect of the first aspect of the present invention is realized at a higher level. be able to.

When the opening (21) is rectangular as in the third aspect of the present invention, both the support portions (34a, 34b) of the movable electrode (30) and the fixed electrode (40,
50) (41a, 41b, 51a, 5)
1b) can be arranged so as to be located and separated on the same set of opposing sides of the edge of the opening.

The invention according to claim 4 provides a specific configuration of the movable electrode and the fixed electrode, and the movable electrode (30) has both ends of the support portion (20) to the support substrate (20). Weight portion (31) connected to the first and second weight portions (34a, 34b)
And the rod-shaped portion (32) protruding from the weight portion, and the fixed electrodes (40, 50) are connected at both ends to the support portions (41a, 41b, 51a, 51b) to the support substrate, respectively. (42, 52) and a bar-shaped portion (43, 53) that protrudes from the connecting portion and whose side surface faces the side surface of the rod-shaped portion of the movable electrode with a detection interval (60).

Further, in the case of the electrode configuration as in the fourth aspect, as in the fifth aspect of the invention, the connecting portion (4
It is preferable to form a bend (44, 54) in the middle of (2, 52) in such a manner as to be bent toward the support (34a, 34b) of the movable electrode (30). .

According to this, both ends of the connection portion of the fixed electrode can be brought closer to the support portion of the movable electrode via the bent portion. Therefore, the supporting portion of the fixed electrode can be made as close as possible to the supporting portion of the movable electrode, and the magnitude of the stress applied from the supporting portion in both electrodes can be made as small as possible.

The reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. In the present embodiment, the present invention is applied to a differential capacitance type semiconductor acceleration sensor as a semiconductor dynamic quantity sensor. FIG. 1 shows a semiconductor acceleration sensor 1
FIG. 2 shows a schematic cross-sectional structure along the line AA in FIG.

A semiconductor acceleration sensor (hereinafter, simply referred to as a sensor) 100 is formed by subjecting a semiconductor substrate to a known micromachining process, similarly to the conventional sensor shown in FIG. As shown in FIG. 2, a semiconductor substrate constituting the sensor 100 includes an oxidation layer serving as an insulating layer between a first silicon substrate 11 serving as a first semiconductor layer and a second silicon substrate 12 serving as a second semiconductor layer. This is a rectangular SOI substrate 10 having a film 13. Here, the first silicon substrate 11 and the oxide film 13 correspond to the support substrate 20 in the present invention.

The support substrate 20 includes a second silicon substrate 12
An opening 21 is formed on the side surface (one surface of the support substrate). Further, a beam structure (in this example, a comb-like shape) including the movable electrode 30 and the fixed electrodes 40 and 50 is formed in the second silicon substrate 12 by forming a groove by trench etching or the like. In the present example, the opening 21 is formed as a portion of the support substrate 20 in which a region where the beam structures 30 to 50 are formed is rectangularly removed so as to penetrate in the thickness direction by anisotropic etching or the like. ing.

The movable electrode 30 made of a semiconductor (in this example, silicon) is supported by the support substrate 20 and is displaced on the opening 21 in response to the application of a physical quantity. In this example,
The movable electrode 30 is disposed so as to cross over the opening 21 between a pair of opposing sides of the edge of the opening 21. The movable electrode 30 has a weight (a rectangular shape in this example) 3
1 and a rod-shaped portion (hereinafter, referred to as a movable rod-shaped portion) 32 protruding from the weight portion 31.

Both ends of the weight 31 are integrally connected to anchors 34a and 34b via beams 33 (in this example, rectangular frames). That is, the anchor portions 34a and 34b are supported and fixed to the support substrate 20 at both edges of the opening 21 facing each other, and the anchor portions 34a and 34b support the movable electrode in the present invention. It is configured as a support for the substrate.

In this embodiment, a plurality of movable rods 32 protruding from the weight 31 extend in opposite directions from both sides of the weight 31 in a direction orthogonal to the displacement direction X of the movable electrode. The projections are formed (four in the illustrated example). These movable rod-shaped portions 32 are formed, for example, in a beam shape having a rectangular cross section.

Here, the beam portion 33 has a spring function of being displaced in a direction perpendicular to the longitudinal direction of the beam, and when receiving an acceleration including a component in the direction of the arrow X in FIG. Displaced in the direction of arrow X, and restored to the original state according to the disappearance of the acceleration. Therefore, the movable electrode 30 can be displaced on the opening 21 in response to the application of the acceleration. Hereinafter, the direction of arrow X in FIG.
That.

The fixed electrodes 40 and 50 made of a semiconductor (silicon in this example) are supported by the support substrate 20 and have openings 21.
It is opposed to the movable electrode 30 with a detection interval 60 above. In this example, the fixed electrodes 40 are provided on both sides (the left and right sides of the movable electrode in FIG. 1) with the displacement direction X of the movable electrode 30 as an axis. Here, the left side of the movable electrode 30 is a first fixed electrode 40, and the right side of the movable electrode 30 is a second fixed electrode 50.

Each of the fixed electrodes 40, 50 is disposed so as to cross over the opening 21 in the same direction as the movable electrode 20, and both ends thereof are anchor portions 41a, 41b, 5b.
It is supported and fixed to the support substrate 20 via 1a and 51b. In other words, both anchor portions of the fixed electrodes 40 and 50 are separated by being located on the same set of opposing sides of the edge portion of the opening 21 as the location where the anchor portions 34a and 34b of the movable electrode 30 are located. , Is configured as a supporting portion of the fixed electrode to the supporting substrate in the present invention.

Each of the fixed electrodes 40, 50 has a connecting portion 42, 52 whose both ends are connected to anchor portions 41a, 41b, 51a, 51b, respectively, and a rod-like portion (hereinafter, fixed) protruding from the connecting portion 42, 52. 43, 53
It is composed of In addition, this fixed rod-shaped portion 43
The side faces the side face of the movable rod 32 with the above-mentioned detection interval 60.

In this example, in each of the fixed electrodes 40 and 50, each of the fixed rod-shaped portions 43 and 53 is moved in the displacement direction X of the movable electrode.
A plurality (four in the illustrated example) is formed so as to extend from the connecting portions 42 and 52 in a direction perpendicular to the direction. And these fixed bar-shaped parts 43 and 53 are formed in the shape of a beam with a rectangular cross section, for example.

In the present embodiment, each of the anchor portions 34a, 34b of the movable electrode 30 is provided in the middle of each of the connecting portions 42, 52.
Bent portions (bent in an L-shape in the illustrated example) 44 and 54 are formed so as to bend toward.

As described above, in the present embodiment, the movable electrode 3
0 anchor portions 34a, 34b and fixed electrodes 40, 5
0 anchor portions 41a, 41b, 51a, and 51b are respectively located at both edges of the opening 21 facing each other, and the direction in which the opposite anchor portions 34a, 34b are separated from each other in the movable electrode 30, and the first fixing The direction separating the two anchor portions 41a and 41b facing each other in the electrode 40 is substantially the same as the direction separating the two anchor portions 51a and 51b facing each other in the second fixed electrode 50.

In other words, the direction (arrangement direction) in which the anchor portions 34a and 34b of the movable electrode 30 are arranged with the opening 21 interposed therebetween, and the both anchor portions 4 of the first fixed electrode 40
The arrangement direction of 1a, 41b and the arrangement direction of both anchor portions 51a, 51b of the second fixed electrode 50 are substantially the same.

In order to suitably realize this configuration, in particular,
In this example, the opening 21 is rectangular, and the movable electrode 30
Anchor portions 34a, 34b and fixed electrodes 4
Both anchor portions 41a and 41b, 51a at 0, 50
And 51b are arranged so as to be located and separated on the same set of opposing sides of the edge of the opening 21.

Further, in this embodiment, as shown in FIG. 1, an axis connecting both anchor portions 34a and 34b of the movable electrode 30 and both anchor portions 41a of the fixed electrodes 40 and 50 are provided.
And 41b, and the axis connecting 51a and 51b is made parallel. That is, these axes are parallel to the displacement direction X of the movable electrode.

The movable electrode 30 and the first fixed electrode 4
0, the second fixed electrode 50 is electrically independent of each other, between the movable rod 32 and each of the fixed rods 43, 53,
That is, a capacitance (detection capacitance) is formed at the detection interval 60.
Here, the capacitance formed at the detection interval 60 between the movable rod 32 and the fixed rod 43 of the first fixed electrode 40 is defined as the first detection capacitance CS1, and the movable rod 32 and the second fixed electrode 50 are fixed. The capacitance formed at the detection interval 60 with respect to the rod 53 is referred to as a second detection capacitance CS2.

Further, at predetermined positions on the support substrate 20, a movable electrode pad 35 which is electrically connected to the movable electrode 30, a first fixed electrode pad 45 which is electrically connected to the first fixed electrode 40, and
Second fixed electrode pad 5 conducting to second fixed electrode 50
5 are formed. In the example shown in FIG. 1, these pads 35, 45, and 55 are respectively connected to the electrodes 30, 40, 5,
0 of the two anchor portions of FIG.
b, 41b, and 51b, and are formed, for example, by aluminum or the like.

Further, a plurality of rectangular through-holes 70 penetrating from the opening 21 side to the opposite side are formed in the weight portion 31, the movable rod-shaped portion 32, and the fixed rod-shaped portions 43, 53. By 70, a so-called ramen structure shape in which a plurality of rectangular frame portions are combined is formed. As a result, the weight of the movable electrode 30 and each of the fixed electrodes 40 and 50 are reduced, and the torsional strength is improved.

Further, as shown in FIG.
Is an adhesive (for example, polyimide resin or the like) on the back surface (the surface opposite to the oxide film 13) of the first silicon substrate 11
It is adhesively fixed to the package 80 via 81.

This package 80 is made of, for example, a ceramic such as alumina, and has a circuit means 9 to be described later.
0 is stored. The circuit means 90 is electrically connected to each of the electrode pads 35, 45, and 55 by a wire (not shown) formed by gold or aluminum wire bonding or the like.

Next, the sensor 10 constructed as described above is used.
The operation of 0 will be described. When the movable electrode 30 is displaced in the displacement direction X in response to the application of acceleration,
This is a differential capacitance type acceleration sensor that detects applied acceleration based on the difference between the first detection capacitance (CS1) and the second detection capacitance (CS2). FIG.
FIG. 3 is a diagram (detection circuit diagram) showing the detection circuit 90 of FIG.

In the detection circuit 90, reference numeral 91 denotes a switched capacitor circuit (SC circuit).
Includes a capacitor 92 having a capacitance of Cf, a switch 93, and a differential amplifier circuit 94.
−CS2) into a voltage.

FIG. 4 shows an example of a timing chart for the detection circuit 90. In the sensor 100, for example, the carrier wave 1 (for example, frequency 100 kHz, amplitude 0 to 5 V) from the first fixed electrode pad 45 and the carrier wave 1 from the second fixed electrode pad 55 are 180 ° in phase.
Shifted carrier 2 (eg, frequency 100 kHz, amplitude 5
０0 V), and the switch 93 of the SC circuit 91 is opened and closed at the timing shown in FIG. Then, the applied acceleration is output as a voltage value V0 as shown in the following Expression 1.

[0049]

V0 = (CS1−CS2) · V / Cf Here, V is a voltage difference between the fixed electrode pads 45 and 55. The applied acceleration along the displacement direction X of the movable electrode is detected from the voltage value V0 output in this manner.

In the present sensor 100, when the operating temperature changes, the movable and fixed electrodes 40, 50,
Due to the difference in the thermal expansion coefficients of the materials (semiconductor, oxide film, resin, ceramic) constituting the support substrate 20, the adhesive 81, and the package 80, the support substrate 20 is deformed such as warpage.

For example, when the support substrate 20 is formed of the beam structures 30 to 5
Consider a case where the shape is deformed so as to be convex toward the surface on which 0 is formed.
FIG. 5 is a diagram for explaining the operation of the present embodiment when such a deformation occurs, and FIG.
FIG. 7 is a diagram showing a direction in which stress is applied to a fixed electrode in the conventional semiconductor dynamic quantity sensor shown in FIG.

In the present embodiment, both anchor portions (both support portions) 34a and 34b of the movable electrode 30 and the fixed electrodes 40, 5
0 Both anchor portions (both support portions) 41a and 41b, 51a
And 51b are both separated (arranged) in substantially the same direction across the opening 21, so that the direction of the stress applied from the anchor portion by the deformation of the support substrate 20 is
0 and the fixed electrodes 40 and 50 are substantially the same.
As shown in (a) and (b), even if a temperature change occurs and the support substrate 20 is deformed in a convex shape, the movable electrode 30, the first fixed electrode 40, and the second fixed electrode 50 Between both anchor portions 34a and 34b, and both anchor portions 41a and 41b.
b, and between the anchor portions 51a and 51b so as to expand or contract in substantially the same direction (in this example, the displacement direction X of the movable electrode, the direction of the outlined arrow in FIG. 5). I do.

Therefore, according to the present embodiment, the direction of the deformation of the movable electrode 30 due to the temperature change and the fixed electrodes 40, 50
Of the movable electrode 30 and the fixed electrode 4 due to the temperature change.
A change in the detection interval 60 between 0 and 50 can be suppressed as much as possible.

Incidentally, in contrast to the present embodiment, the support portion 211 of the conventional sensor fixed electrode 205 is located on a different set of opposing sides of the edge of the opening 210 from the opposing side where the movable electrode 204 is located. (See FIG. 7 above). Therefore, when the support substrates 201 and 203 are warped in a convex shape, stress is applied to the fixed electrode 205 from the support portion 211 in a direction different from that of the movable electrode as shown by a white arrow in FIG. Therefore, in the conventional sensor, the detection interval is displaced because the manner of deformation differs between the movable electrode and the fixed electrode.

In particular, in this embodiment, as shown in FIG. 1, both anchor portions 34a of the movable electrode 30 are provided.
It is preferable that the axis connecting the fixed electrodes 40b and 34b and the axis connecting the two anchor portions 41a and 41b and 51a and 51b of the fixed electrodes 40 and 50 are parallel to each other. Thereby, the supporting substrate 2
The direction of the stress applied from the anchor part by the deformation of 0
Because the movable electrode and the fixed electrode can be matched,
At a higher level, the effect of suppressing the change in the detection interval 60 can be realized.

In the present sensor 100, the movable electrode 30
Are composed of a weight portion 31 and a rod-shaped portion 32, and the fixed electrodes 40, 5
In the case where 0 is composed of connecting portions 42, 52 and rod-shaped portions 43, 53, as shown in FIG.
52, each anchor portion 34a of the movable electrode 30;
A preferred form in which the bent portions 44 and 54 bent toward the direction 34b are adopted.

According to this, both ends of the connecting portions 42 and 52 can be brought closer to the anchor portions 34a and 34b of the movable electrode 30 via the bent portions 44 and 54. Therefore, the anchor portions 41a and the like of the fixed electrodes 40 and 50 can be realized as close as possible to the anchor portions 34a and 34b of the movable electrode 30.
The values of 0 and 50 are preferable because the magnitude of the stress applied from the anchor portions 34a and 41a can be made as much as possible.

(Other Embodiments) The support substrate having an opening formed on one surface side is not limited to a semiconductor such as silicon, but may be a material such as glass or ceramic.
The shape of the opening is not limited to a rectangle, but may be a circle, a polygon other than a square, or the like.

Further, the opening does not have to penetrate the support substrate, but may be a concave opening on one side. For example, in the SOI (silicon-on-insulator) substrate 10 shown in FIG. 2, the oxide film 13 located in the formation region of the opening is removed by sacrifice layer etching or the like so that the first silicon substrate 11 remains. Thus, an opening as a recess may be formed.

The movable electrode and the fixed electrode may have any geometric shape other than the comb shape shown in FIG. 1 as long as the electrodes face each other with a detection interval. can do. Also, the number of detection intervals may be one instead of a plurality.

Further, the present invention provides a method other than the acceleration sensor,
The present invention can be applied to a semiconductor dynamic quantity sensor that detects a dynamic quantity such as an angular velocity sensor and a pressure sensor.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a semiconductor acceleration sensor according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a detection circuit diagram of the semiconductor acceleration sensor shown in FIG.

4 is a diagram showing an example of a timing chart for the detection circuit shown in FIG. 3;

FIG. 5 is an operation explanatory view of the embodiment.

FIG. 6 is a diagram illustrating an example of a direction of stress applied to a fixed electrode in a conventional semiconductor dynamic quantity sensor.

FIG. 7 is a diagram showing a general configuration of a conventional semiconductor dynamic quantity sensor.

[Explanation of symbols]

Reference numeral 20: support substrate, 21: opening, 30: movable electrode, 31
... weight part, 32 ... rod-shaped part (movable rod-shaped part), 34a, 34b
... anchor part of movable electrode, 40 ... first fixed electrode, 41
a, 41b: anchor portion of first fixed electrode, 42: first
Connecting portions of fixed electrodes, 43: rod-shaped portion (fixed bar-shaped portion) of first fixed electrode, 44, 54: bent portion, 50: second fixed electrode, 51a, 51b: anchor portion of second fixed electrode , 52... A connecting portion of the second fixed electrode, 53... A bar portion (fixed bar portion) of the second fixed electrode, 60.

Claims (5)

[Claims] 1. A support substrate (20) having an opening (21) opened on one surface side, and a semiconductor supported by the support substrate and displaced on the opening in response to application of a physical quantity. A movable electrode (30), and a fixed electrode (40, 50) made of a semiconductor supported by the support substrate and opposed to the movable electrode at the opening with a detection interval (60), and When the movable electrode is displaced in response to the application of a force, a semiconductor dynamic quantity sensor that detects an applied dynamic quantity based on a change in the detection interval, wherein a support portion (34a, 34) of the movable electrode to the support substrate
b) and a support portion (4) of the fixed electrode to the support substrate.
1a, 41b, 51a, and 51b) are located at both edges of the opening facing each other, and a direction separating the two support portions of the movable electrode and a direction separating the two support portions of the fixed electrode. Are substantially the same. 2. The fixed electrode (4), wherein an axis connecting the supporting portions (34a, 34b) of the movable electrode (30) and the fixed electrode (4).
0, 50) at the two support portions (41a, 41b, 5).
The semiconductor physical quantity sensor according to claim 1, wherein an axis connecting 1a and 51b) is parallel. 3. The opening (21) is rectangular, and the support portions (34a, 34a,
34b), both of the support portions (41a, 41b, 51a, 51b) of the fixed electrode (40, 50) are located and separated on the same set of opposing sides of the edge of the opening. The semiconductor dynamic quantity sensor according to claim 1 or 2, wherein: 4. Both ends of the movable electrode (30) are supported by the support portions (34a, 34a) to the support substrate (20).
The fixed electrode (40, 50) comprises a weight portion (31) connected to the support substrate (b) and a rod-shaped portion (32) protruding from the weight portion. 41a, 41b, 51a, 51
(b) a connecting portion (42, 52) connected to the movable electrode, and a side bar (43, 53) projecting from the connecting portion and having a side face facing the side surface of the bar portion of the movable electrode with the detection interval (60).
4. The semiconductor physical quantity sensor according to claim 1, wherein 5. The support portion (34) of the movable electrode (30) is provided at an intermediate portion of the connection portion (42, 52).
a, 34b).
The semiconductor physical quantity sensor according to claim 4, wherein (54) is formed.