JP7107527B2 - Sensors, structures and electrical equipment - Google Patents

Description

Embodiments of the present invention relate to sensors, structures and electrical devices.

Acceleration sensors formed using MEMS (Micro Electro Mechanical Systems) technology (hereinafter referred to as MEMS acceleration sensors) are known for detecting acceleration. This MEMS acceleration sensor is formed using a semiconductor process. Therefore, the performance of the MEMS acceleration sensor is affected by the semiconductor process.

U.S. Pat. No. 8,820,161

SUMMARY OF THE INVENTION An object of the present invention is to provide a sensor, a structure, and an electric device capable of suppressing deterioration in performance.

A sensor according to an embodiment includes a substrate, a first fixed electrode provided on the substrate, a second fixed electrode provided on the substrate, and the first fixed electrode and the second fixed electrode. and a movable electrode having an opening. The sensor further includes a first torsion spring having one end connected to the inner wall of the opening, and a first torsion spring connected to the other end of the first torsion spring and having a bent portion when viewed from above the opening. beams and The sensor further includes a second torsion spring having one end connected to the inner wall of the opening, and a second torsion spring connected to the other end of the second torsion spring and having a bent portion when viewed from above the opening. beams and

The structure of the embodiment includes the substrate of the sensor, the first fixed electrode, the second fixed electrode, the movable electrode, the first torsion spring, the first beam, the second torsion spring and the second beam. include.
An electrical device of an embodiment includes the sensor described above.

FIG. 1 is a plan view schematically showing a MEMS acceleration sensor according to one embodiment. FIG. 2 is a cross-sectional view taken along line 2--2 in FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 1. FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 1. FIG. FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 6 is a cross-sectional view corresponding to FIG. 2 when a force acts on the MEMS acceleration sensor of FIG. 1. FIG. FIG. 7 is a plan view and a sectional view schematically showing a MEMS acceleration sensor of a comparative example. FIG. 8 is a diagram for explaining why the MEMS acceleration sensor according to the embodiment can suppress a decrease in detection sensitivity. FIG. 9 is a sectional view corresponding to FIG. 3 of the MEMS acceleration sensor in which the movable electrode is warped. FIG. 10 is a sectional view corresponding to FIG. 4 of the MEMS acceleration sensor in which the movable electrode is warped. FIG. 11 is a cross-sectional view corresponding to FIG. 5 of the MEMS acceleration sensor in which the movable electrode is warped. FIG. 12 is a plan view for explaining dimensions of the MEMS acceleration sensor of the embodiment. FIG. 13 is a cross-sectional view for explaining the method of manufacturing the MEMS acceleration sensor of the embodiment. FIG. 14 is a plan view schematically showing a MEMS acceleration sensor of another embodiment. FIG. 15 is a block diagram showing a MEMS acceleration sensor of still another embodiment.

Embodiments of the present invention will be described below with reference to the drawings. The drawings are schematic or conceptual, and the dimensions, proportions, etc. of each drawing are not necessarily the same as the actual ones. In the drawings, the same reference numerals denote the same or corresponding parts, and redundant description will be given as necessary. Also, for the sake of simplification, even if there are the same or corresponding parts, they may not be labeled.

FIG. 1 is a plan view schematically showing a MEMS acceleration sensor according to one embodiment. FIG. 2 is a cross-sectional view taken along line 2--2 in FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 1. FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 1. FIG. FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. The cross-sectional views of FIGS. 2 to 5 show states in which no force acts on the MEMS acceleration sensor.

2 to 5, reference numeral 10 indicates a substrate, and this substrate 10 includes a silicon substrate 11 and a silicon oxide film 12 provided thereon. 2 to 5 show only the upper portion of the silicon substrate 11 for simplification.
As shown in FIG. 2, a first fixed electrode 21 is provided on the upper surface 10a (first surface) of the substrate 10. As shown in FIG. Here, the upper surface 10 a of the substrate 10 is the upper surface of the silicon oxide film 12 .

In FIG. 1, the X-axis (first axis) is the axis within the top surface 10a of the substrate 10 in FIG. 2, the Y-axis (second axis) is the axis within the top surface 10a of the substrate 10, is the axis perpendicular to Also, the Z-axis (third axis) is an axis perpendicular to the X-axis and the Y-axis. As shown in FIG. 1, the first fixed electrode 21 extends along the X-axis.

A second fixed electrode 22 is further provided on the upper surface 10 a of the substrate 10 . The second fixed electrode 22 extends along the X-axis and is spaced apart from the first fixed electrode 21 along the Y-axis. The area of the second fixed electrode 22 is the same as the area of the first fixed electrode 11 . The distance from the torsion spring 31 to the second fixed electrode 22 is the same as the distance from the torsion spring 31 to the first fixed electrode 21 . A wiring layer 23 is provided on the upper surface 10 a of the substrate 10 . A silicon nitride film (etching stopper) 24 is provided on the silicon oxide film 12 , the first fixed electrode 21 , the second fixed electrode 22 and the wiring layer 23 .

As shown in FIGS. 1 and 2, a movable electrode 26 having an opening 25 is arranged above the first fixed electrode 21 and the second fixed electrode 22 . When manufacturing the MEMS acceleration sensor of this embodiment using a sacrificial film process, the movable electrode 26 has a plurality of through holes (not shown).

One end of a first torsion spring 31 is connected to the inner wall of the opening 25 . The first torsion spring 31 extends along the X-axis. The other end of the first torsion spring 31 is connected to a first beam portion 41 having a bent portion when viewed from above the opening 25, as shown in FIG. The bent portion of the first beam portion 41 is connected to a rectangular parallelepiped portion 41a parallel to the X-axis, connected to this portion 41a, connected to a rectangular parallelepiped portion 41b parallel to the Y-axis, connected to this portion 41b, and connected to the X-axis. and a rectangular parallelepiped portion 41c parallel to the axis. The other end of the first torsion spring 31 is connected to the central portion of the portion 41 b of the first beam portion 41 . A first torsion spring 31 is connected to the movable electrode 26 .

As shown in FIG. 1, an anchor portion 51 and an anchor portion 52 are arranged on a substrate (not shown) so as to sandwich the first torsion spring 31 therebetween. Anchor portion 51 and anchor portion 52 are arranged at a constant distance from first torsion spring 31 . Anchor portion 51 is connected to portion 41a, and anchor portion 52 is connected to portion 41c.

As shown in FIG. 2, the anchor portions 51 and 52 penetrate through the silicon nitride film 24 and are electrically connected to the wiring layer 23 . As shown in FIG. 4 , anchor portion 51 includes insulating film 61 and plug 62 . The material of the plug 62 is tungsten, for example. Plug 62 is electrically connected to wiring layer 23 through insulating film 61 and insulating layer 24 . Although the number of plugs 62 is four in this embodiment, the number is not limited to four. The configuration of the anchor portion 52 is the same as the configuration of the anchor portion 51 . The first beam portion 41 , the anchor portion 51 and the anchor portion 52 have a line-symmetrical pattern with respect to the first torsion spring 31 .

One end of a second torsion spring 32 is connected to the inner wall of the opening 25 . A second torsion spring 32 extends along the X-axis. A portion (first connecting portion) of the inner wall of the opening 25 to which one end of the first torsion spring 31 is connected is a portion (second connecting portion) of the inner wall of the opening 25 to which one end of the second torsion spring 32 is connected. connection part). More specifically, the first connecting portion and the second connecting portion are opposed along the X-axis.

The other end of the second torsion spring 32 is connected to a second beam portion 42 having a bent portion when viewed from above the opening 25, as shown in FIG. The bent portion of the second beam portion 42 is connected to a rectangular parallelepiped portion 42a parallel to the X-axis and connected to this portion 42a, and connected to a rectangular parallelepiped portion 42b parallel to the Y-axis and connected to this portion 42b. and a rectangular parallelepiped portion 42c parallel to the axis. The other end of the second torsion spring 32 is connected to the central portion of the portion 42b. There is a gap between the portion 42b and the portion 41b. The second torsion spring 32 is connected to the movable electrode 26 like the first torsion spring 31 .

As shown in FIG. 1, anchor portions 53 and 54 are arranged on a substrate (not shown) so as to sandwich the second torsion spring 32 therebetween. Anchor portion 53 and anchor portion 54 are arranged at a constant distance from second torsion spring 32 . Anchor portion 53 is connected to portion 42a, and anchor portion 54 is connected to portion 42c.

Anchor portion 51 and anchor portion 54 indirectly contact substrate 10 . Anchor portion 53 and anchor portion 54 have the same configurations as anchor portion 51 and anchor portion 52, respectively.
As shown in FIG. 1, when viewed from above the opening 25, the torsion spring 31, the first beam portion 41, the anchor portion 51, the torsion spring 32, the first beam portion 41 and the anchor portion 51 are positioned within the opening. are placed. Further, as shown in FIG. 1 , when viewed from above the opening 25 , the first pattern formed by the first beam portion 41 , the anchor portion 51 and the anchor portion 52 is the second beam portion with respect to the line 50 . It is axisymmetric with respect to the second pattern formed by the portion 42 , the anchor portion 53 and the anchor portion 54 . A line 50 is a line that passes through the center between the portion 41b of the first beam 41 and the portion 42b of the second beam 42 and is parallel to the Y-axis. The first pattern is not directly connected to the second pattern. The first pattern is connected via the first torsion spring 31 , the movable electrode 26 and the second torsion spring 32 .

In this embodiment, the movable electrode 26, the first torsion spring 31, the second torsion spring 32, the first beam portion 41, and the second beam portion 42 are made of the same film material. However, they do not necessarily have to be films of the same material.
As shown in FIG. 2, the first fixed electrode 21 and movable electrode 26 constitute a first capacitor C1, and the second fixed electrode 22 and movable electrode 26 constitute a second capacitor C2. . In FIG. 2, the spacing between the first fixed electrode 21 and the movable electrode 26 is the same as the spacing between the second fixed electrode 22 and the movable electrode 26, and the capacitance of the first capacitor C1 is the second It is the same as the capacitance of capacitor C1. Hereinafter, the capacitance is simply referred to as capacity.

FIG. 6 is a cross-sectional view corresponding to FIG. 2 when force acts on the MEMS acceleration sensor of this embodiment. The force includes a force perpendicular to the top surface 10 a of the substrate 10 .
When the vertical force acts on the MEMS acceleration sensor, the torsion spring 31 and the torsion spring 32 are twisted, and the distance between the first fixed electrode 21 and the movable electrode 26 becomes the distance between the second fixed electrode 22 and the movable electrode 26. is no longer the same as the interval of As a result, the capacitance between the first fixed electrode 21 and the movable electrode 26 will be different from the second capacitance between the second fixed electrode 22 and the movable electrode 26 . The difference between these capacities (capacity difference) changes according to the magnitude of the vertical force. Therefore, the acceleration in the Z-axis direction (height direction) can be calculated based on the capacitance difference. Capacitance difference detection and acceleration calculation are performed using, for example, a circuit (not shown) formed in the silicon substrate 11 . The circuit is configured using, for example, a CMOS circuit. A CMOS circuit is formed using a silicon substrate 11 and a silicon oxide film 12 .

The movable electrode 26 is formed using, for example, a silicon germanium film, a silicon film, a laminated film of a silicon film and a silicon oxide film, or a laminated film of a silicon oxide film, a silicon film and a silicon oxide film. When these films are formed using a CVD (Chemical Vapor Deposition) process, the films described above are warped. One cause of warpage is the generation of residual stress in films formed using CVD processes. Another cause is that thermal expansion occurs in the film due to temperature changes during or after the CVD process. As a result, as shown in FIG. In the case of the MEMS acceleration sensor (comparative example) of the type in which the movable electrode 26 is supported by the anchor portion 51, the movable electrode 26 is warped as shown in FIG. 7(b). In FIG. 7B, the warped movable electrode 26 is schematically indicated by a solid line. A movable electrode without warpage is schematically indicated by a dashed line. As shown in FIG. 7B, the movable electrode 26 is warped such that the peripheral portion of the movable electrode 26 is positioned above the central portion of the movable electrode 26 .

In the case of FIG. 7, the spacing between the warped movable electrode 26 and the fixed electrode (not shown) is greater than the spacing between the non-warped movable electrode and the fixed electrode (not shown). Therefore, a MEMS acceleration sensor using such a warped movable electrode 26 has lower acceleration detection sensitivity than a MEMS acceleration sensor using a non-warped movable electrode. Here, the acceleration detection sensitivity is defined by the capacitance change per unit acceleration. In the case of this embodiment, the MEMS acceleration sensor is a differential acceleration sensor that detects acceleration based on the capacitance difference described above, so the acceleration detection sensitivity is defined by the capacitance difference (=capacitance C2−capacitance C1).

However, when the MEMS acceleration sensor of this embodiment was evaluated, it was confirmed that the decrease in acceleration detection sensitivity can be suppressed. The reason is considered as follows.
FIG. 8(a) is a plan view corresponding to FIG. FIG. 8(b) is a cross-sectional view taken along line 8b-8b of FIG. 8(a). In FIG. 8(b), the warped movable electrode 26 is schematically indicated by a solid line, and the movable electrode without warp is schematically indicated by a broken line.

As shown in FIGS. 8A and 8B, in a region 71 outside the anchor portion 51 (52) with respect to the X axis, the warped movable electrode 26 is above the non-warped movable electrode. Similarly, in the region 72 outside the anchor portion 53 (54) with respect to the X-axis, the warped movable electrode 26 is above the non-warped movable electrode. Therefore, the detection sensitivity is lowered in the regions 71 and 72 .

On the other hand, in a region 73 inside the anchor portion 51 (52) and inside the anchor portion 53 (54) with respect to the X axis, the warped movable electrode 26 is positioned below the non-warped movable electrode. be. Therefore, detection sensitivity is improved in the region 73 .
In the case of the present embodiment, since the degree of improvement in the acceleration detection sensitivity in the region 73 is substantially the same as the degree of deterioration in the acceleration detection sensitivity in the regions 71 and 72, the reduction in the acceleration detection sensitivity is suppressed. It is possible.

When the amount of warpage of the movable electrode 26 is defined by the radius of curvature, for example, if the radius of curvature is within the range of 20 mm to 200 mm, it is possible to suppress deterioration in acceleration detection sensitivity.
In FIG. 8(b), G1 is the distance measured along the Z axis, and the maximum distance (gap) from the non-warped movable electrode 26 to the warped movable electrode 26 in the region 73. is shown.

FIG. 9 shows a sectional view corresponding to FIG. 3 of the MEMS acceleration sensor in which the movable electrode 26 is warped, and FIG. 10 is a sectional view corresponding to FIG. 4 of the MEMS acceleration sensor in which the movable electrode 26 is warped. 5, and FIG. 11 shows a cross-sectional view corresponding to FIG. 5 of the MEMS acceleration sensor in which the movable electrode 26 is warped. In FIGS. 9 to 11, dashed lines indicate movable electrodes without warpage.

FIG. 12 is a plan view for explaining dimensions of the MEMS acceleration sensor. In FIG. 12, X1 and X2 indicate dimensions parallel to the X axis, and Y1 to Y4 indicate dimensions parallel to the Y axis. In order to avoid complication of the drawing, reference numerals such as the movable electrode and the torsion spring are not attached.

The width X1 of the movable electrode is set in the range of 300 to 1000 μm, for example.
The length Y1 of the movable electrode is set in the range of 300 to 2000 μm, for example.
The width X2 of the torsion spring is set in the range of 0.5 to 5 μm, for example.
The length Y2 of the torsion spring is set within a range of 25 to 45% of Y1, for example.

A distance Y3 from the center of the movable electrode to the anchor portion is set, for example, within a range of ⅛ to ⅓ of Y1. In other words, the distance Y4 (=2×Y3) between the anchor portions is set within the range of 2/8 (=1/4) to 2/3 of Y1. Specifically, the distance Y4 between the anchor portions is set in the range of 200 to 500 μm, for example. If Y3 (Y4) is set within the above range, the gap G1 shown in FIG. 8B can be made 2 μm or more. In this case, since the average initial capacitance value does not change even if warping occurs, it is possible to suppress a decrease in detection sensitivity for warping. For example, if the radius of curvature is 50 nm or more, even if warping occurs, the decrease in detection sensitivity can be kept within 10%.

Although not shown in FIG. 12, the minimum distance between the first fixed electrode (second fixed electrode) and the movable electrode is set in the range of 1 to 3 μm, for example.
Next, a method for manufacturing the MEMS acceleration sensor of this embodiment will be briefly described with reference to FIGS. 13(a) to 13(f). 13(a) to 13(f) correspond to cross-sectional views along the arrow 2-2 in FIG. In this embodiment, a manufacturing method using a sacrificial film process will be described.

First, as shown in FIG. 13A, a silicon oxide film 12 is formed on a silicon substrate 11 . Next, on the silicon oxide film 12, a conductive film that becomes the first fixed electrode 21, the second fixed electrode 22 and the wiring layer 23 is formed, and then the conductive film is patterned to form the first fixed electrode. 21, a second fixed electrode 22 and a wiring layer 23 are formed. The thickness of the conductive film is, for example, 0.6 μm.

Next, as shown in FIG. 13B, a silicon nitride film 24 is formed on the first fixed electrode 21, the second fixed electrode 22 and the wiring layer 23. Next, as shown in FIG. The thickness of the silicon nitride film 24 is, for example, 1 μm. After that, a silicon oxide film 61 is formed on the silicon nitride film 24 as a sacrificial film and as an insulating film for the anchor portion. The thickness of the silicon oxide film 61 is, for example, 1 to 3 μm. CMP (Chemical Mechanical Polishing) may be performed to sufficiently planarize the surface of the silicon oxide film 61 .

Next, as shown in FIG. 13C, plugs 62 are formed through the silicon oxide film 61 . More specifically, first, through holes are formed through the silicon oxide film 61 using an etching process. At this time, the silicon nitride film 24 functions as an etching stopper. The etching process is performed using, for example, RIE (Reactive Ion Etching). Next, a conductive film is formed on the entire surface so as to fill the through holes, and then excess conductive film is removed by CMP.

Next, as shown in FIG. 13(d), a film to be the movable electrode 26, for example, a silicon germanium film is formed on the silicon oxide film 61 using a CVD process. An electrode 26 is formed. It should be noted that in the drawing, the warp that occurs in the movable electrode 26 is omitted for the sake of simplification. For the patterning, for example, DRIE (Deep Reactive Ion Etching), which is one of RIE, is used.

Next, as shown in FIG. 13(e), an etching process is used to form openings 25 and a plurality of through holes 27 in the movable electrode 26. Next, as shown in FIG. The through hole 27 is not formed on the portion of the anchor portion that will become the insulating film. The etching process is performed using, for example, DRIE.
Next, hydrogen fluoride gas (HF gas) is introduced from the opening 25 and the through hole 27 to selectively remove the portion of the silicon oxide film 13 that is not used as the insulating film of the anchor portion. As a result, as shown in FIG. 13(f), the insulating film 61 of the anchor portion made of a silicon oxide film is formed. After that, a well-known MEMS acceleration sensor manufacturing process is performed.

FIG. 14 is a plan view schematically showing a MEMS acceleration sensor according to another embodiment.
This embodiment differs from the previous embodiment in that the number of anchor portions is reduced from four to two. More specifically, the two anchor portions 52, 54 shown in FIG. 1 have been omitted.
As the number of anchor portions is reduced, the bent portion of the first beam portion 41 and the bent portion of the second beam portion 42 are changed. More specifically, in the bent portion of the first beam portion 41 of this embodiment, the portion 41c shown in FIG. 1 is omitted. In the bent portion of the second beam portion 42 of this embodiment, the portion 42c shown in FIG. 1 is omitted. Further, in the case of this embodiment, the other end of the first torsion spring 31 is connected to the end of the portion 41b of the first beam portion 41, and the other end of the second torsion spring 32 is connected to the second beam portion 42. is connected to the end of the portion 42b. Note that the number of anchor portions may be one or more.

FIG. 15 is a block diagram showing a MEMS acceleration sensor of still another embodiment.
The MEMS acceleration sensor of this embodiment includes a MEMS acceleration sensor 1X that detects acceleration in the X-axis direction, a MEMS acceleration sensor 1Y that detects acceleration in the Y-axis direction, and a MEMS acceleration sensor 1Z that detects acceleration in the Z-axis direction. including.

The MEMS acceleration sensor 1X and the MEMS acceleration sensor 1Y are well-known MEMS acceleration sensors configured using, for example, comb-shaped fixed electrodes and comb-shaped movable electrodes. On the other hand, the MEMS acceleration sensor 1Z is the MEMS acceleration sensor of the embodiments shown in FIGS.

Some or all of the broader concepts, middle concepts, and lower concepts of the sensor of the above-described embodiments, and other embodiments not described above are, for example, the following Appendix 1-11 and Appendix 1-11 It can be expressed in any combination (excluding combinations that are clearly contradictory).
[Appendix 1]
a substrate;
a first fixed electrode provided on the substrate;
a second fixed electrode provided on the substrate;
a movable electrode disposed above the first fixed electrode and the second fixed electrode and having an opening;
a first torsion spring having one end connected to the inner wall of the opening;
a first beam connected to the other end of the first torsion spring and having a bent portion when viewed from above the opening;
a second torsion spring having one end connected to the inner wall of the opening;
a second beam connected to the other end of the second torsion spring and having a bent portion when viewed from above the opening.
[Appendix 2]
the substrate has a first surface;
The first fixed electrode and the second fixed electrode are provided on the first surface,
the first fixed electrode extends along a first axis in the first plane;
The second fixed electrode extends along the first axis and is spaced apart from the first fixed electrode along a second axis in the first plane. 1. The sensor according to claim 1.
[Appendix 3]
said first torsion spring extending along said first axis;
3. The sensor of Claim 2, wherein the second torsion spring extends along the first axis.
[Appendix 4]
3. A portion of the inner wall of the opening to which one end of the first torsion spring is connected faces a portion of the inner wall of the opening to which one end of the second torsion spring 32 is connected. sensor.
[Appendix 5]
The bent portion of the first beam includes a first portion parallel to the first axis and a second portion connected to the first portion and parallel to the second axis. ,
The bent portion of the second beam includes a third portion parallel to the first axis and a fourth portion connected to the third portion and parallel to the second axis. 5. The acceleration sensor according to any one of Appendices 2 to 4.
[Appendix 6]
further comprising a first anchor portion and a second anchor portion provided on the substrate;
the first portion of the first beam is connected to the first anchor;
6. The sensor of Clause 5, wherein the third portion of the second beam is connected to the second anchor portion.
[Appendix 7]
further comprising a third anchor portion and a fourth anchor portion provided on the substrate;
the bent portion of the first beam further includes a fourth portion connected to the third anchor portion;
7. The sensor of clause 6, wherein the bent portion of the second beam further includes a fifth portion connected to the fourth anchor portion.
[Appendix 8]
Appendix 6, wherein the distance between the first anchor portion and the second anchor portion is 1/4 or more and 2/3 or less of the length of the side of the movable electrode parallel to the first axis, or 7. The sensor according to 7.
[Appendix 9]
9. The sensor according to any one of appendices 6 to 8, wherein the distance between the first anchor portion and the second anchor portion is 200 μm or more and 500 μm or less.
[Appendix 10]
10. The sensor according to any one of claims 1 to 9, wherein the movable electrode is warped and the peripheral portion of the movable electrode is located above the central portion of the movable electrode.
[Appendix 11]
11. Any one of appendices 1 to 10, wherein the movable electrode includes a silicon germanium film, a silicon film, a laminated film of a silicon film and a silicon oxide film, or a laminated film of a silicon oxide film, a silicon film and a silicon oxide film. sensor.

Further, in the above-described embodiments, the sensor has been described, but the substrate, the first fixed electrode, the second fixed electrode, the movable electrode, the first torsion spring, the first beam, and the second It may be implemented as a structure including a torsion spring and a second beam. The structure is, for example, a sensor structure configured to perform a sensor function by mechanically, electrically, or mechanically and electrically connecting elements such as the substrate and fixed electrodes.

Moreover, it may be implemented as an electric device (or an electronic device) including the sensor of the embodiment. The electric device (or electronic device) may include, for example, an element that performs a predetermined operation or processing (for example, information processing) or both based on the acceleration detected by the sensor. The elements are implemented by, for example, hardware such as circuits, software such as programs, or a combination of hardware and software.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

G1 Gap 1X, 1Y, 1Z MEMS acceleration sensor 10 Substrate 10a Top surface of substrate (first surface) 11 Silicon substrate 12 Silicon oxide film 21 First fixed electrode 22 Second fixed electrode 23 Wiring layer 24 Silicon nitride film (etching stopper) 25 Opening 26 Movable electrode 27 Through hole 31 First torsion spring 32 Second torsion Spring 41 First beam portion 41a to 41c Part of first beam portion 42 Second beam portion 42a to 42c Part of second beam portion 51 Anchor portion (first beam portion) Anchor portion), 52 Anchor portion (third anchor portion), 53 Anchor portion (second anchor portion), 54 Anchor portion (fourth anchor portion), 61 Insulating film (sacrificial film), 62 …plug.

Claims (10)

a substrate having a first surface ;
a first fixed electrode provided on the first surface and extending along a first axis ;
a second electrode provided in the first plane and extending along a first axis and spaced apart from the first fixed electrode along a second axis in the first plane ; a fixed electrode;
a movable electrode spaced apart from the first surface in a first direction and having an opening when viewed from a second direction opposite to the first direction ;
a first torsion spring having one end connected to the inner wall of the opening and extending along the first axis ;
a first beam connected to the other end of the first torsion spring and having a first bent portion when viewed from the second direction ;
a second torsion spring having one end connected to the inner wall of the opening and extending along the first axis ;
a second beam connected to the other end of the second torsion spring and having a second bent portion when viewed from the second direction ;
When viewed from the second direction, the first beam portion having the first bent portion and the second beam portion having the second bent portion are separated by the opening,
The sensor according to claim 1, wherein the movable electrode is curved along the first axis such that a peripheral portion of the movable electrode is separated from a central portion of the movable electrode in the first direction . 2. A portion of the inner wall of the opening to which one end of the first torsion spring is connected faces a portion of the inner wall of the opening to which one end of the second torsion spring is connected. sensor. The first bent portion of the first beam portion includes a first portion parallel to the first axis and a second portion connected to the first portion and parallel to the second axis. and
The second bent portion of the second beam portion includes a third portion parallel to the first axis and a fourth portion connected to the third portion and parallel to the second axis. 3. The sensor of claim 2, comprising: further comprising a first anchor portion and a second anchor portion provided on the substrate;
the first portion of the first beam is connected to the first anchor;
4. The sensor of claim 3 , wherein said third portion of said second beam is connected to said second anchor portion. further comprising a third anchor portion and a fourth anchor portion provided on the substrate;
the first bent portion of the first beam further includes a fifth portion connected to the third anchor portion;
5. The sensor of claim 4 , wherein said second bend of said second beam further comprises a sixth portion connected to said fourth anchor portion. 5. The distance between the first anchor portion and the second anchor portion is 1/4 or more and 2/3 or less of the length of the side of the movable electrode parallel to the first axis. Or the sensor according to 5 . 7. The sensor according to any one of claims 4 to 6 , wherein the distance between said first anchor portion and said second anchor portion is 200 [mu]m or more and 500 [mu]m or less. 8. The movable electrode according to any one of claims 1 to 7 , wherein the movable electrode includes a silicon germanium film, a silicon film, a laminated film of a silicon film and a silicon oxide film, or a laminated film of a silicon oxide film, a silicon film and a silicon oxide film. Described sensor. The substrate, the first fixed electrode, the second fixed electrode, the movable electrode, the first torsion spring, the first beam portion, the second torsion spring and the second beam according to any one of claims 1 to 8 . A structure containing parts. An electrical device comprising a sensor according to any one of claims 1-8 .

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