JP2011196905A - Mems structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a MEMS structure which maintains a relative position relationship between a movable electrode and a fixed electrode even if a warp occurs on a supporting substrate.SOLUTION: An acceleration sensor 10 includes a supporting substrate 21, a displacement member 41, a movable electrode 51, a fixed electrode 52, a first beam 42, a first fixed part 43, a second beam 53, a second fixed part 54. The fixed electrode 52 is supported by the supporting substrate 21 via the second beam 53. The distance between the first fixed part 43 and the second fixed part 54 is shorter than the distance between the first fixed part 43 and the fixed electrode 52.

Description

  The present invention relates to a MEMS (Micro Electro Mechanical Systems) structure.

  A technique for forming a MEMS structure that exhibits a specific function using a semiconductor manufacturing technique has been developed. This type of MEMS structure includes, for example, a sensor for measuring a physical quantity such as acceleration, angular velocity or pressure (including sound pressure), an optical mirror, or an actuator for driving a stage with a single axis or multiple axes. Has been proposed.

  The MEMS structure is provided with a displacement portion that can be displaced relative to the support substrate. For example, when a MEMS structure is used as a sensor, a displacement portion that receives a force such as acceleration, angular velocity, pressure, or the like and is displaced relative to the support substrate is required. Further, even when the MEMS structure is used as an actuator, a displacement portion that transmits a force such as an electrostatic force or a magnetic force to be displaced relative to the support substrate is required.

  In this type of MEMS structure, a movable electrode portion is connected to the displacement portion, and a fixed electrode portion is often provided on the support substrate so as to face the movable electrode portion. The movable electrode portion is displaced relative to the support substrate depending on the displacement of the displacement portion. On the other hand, the fixed electrode portion is rigidly fixed to the support substrate and is prohibited from being displaced relative to the support substrate. For this reason, the interval between the movable electrode portion and the fixed electrode portion varies depending on the displacement of the movable electrode portion. When the movable electrode portion and the fixed electrode portion are used, the displacement amount of the displacement portion can be measured from the capacitance between the movable electrode portion and the fixed electrode portion. Or an electrostatic attraction can be generated between a movable electrode part and a fixed electrode part, and a displacement part can be driven. An example of an acceleration sensor having this type of MEMS structure is disclosed in Patent Document 1.

JP 2004-294332 A

  As disclosed in Patent Document 1, the displacement portion is fixed to the support substrate via the beam portion. For this reason, the movable electrode part connected to the displacement part is also fixed to the support substrate via the beam part. As a result, the position where the movable electrode portion exists and the position where the movable electrode portion is fixed to the support substrate (that is, the fixed portion where the beam portion is fixed to the support substrate) are separated from each other. On the other hand, the fixed electrode portion is disposed so as to face the movable electrode portion, and is rigidly fixed to the support substrate at the position where the fixed electrode portion is present. For this reason, in this type of MEMS structure, the distance between the position where the movable electrode portion is fixed to the support substrate and the position where the fixed electrode portion is fixed to the support substrate is large.

  Generally, when manufacturing a MEMS structure, thermal stress is often applied to a support substrate. For this reason, the support substrate may be warped due to thermal stress during the manufacturing process. If the position where the movable electrode portion is fixed to the support substrate and the position where the fixed electrode portion is fixed to the support substrate are separated, when the support substrate is warped, the movable electrode portion and the fixed electrode according to the warpage The relative positional relationship of the parts will fluctuate. If the position where the movable electrode portion is fixed to the support substrate and the position where the fixed electrode portion is fixed to the support substrate are separated from each other, the movable electrode portion is easily affected by the warp of the support substrate.

  An object of the technology disclosed in the present specification is to provide a MEMS structure in which the relative positional relationship between the movable electrode portion and the fixed electrode portion is maintained even when the support substrate is warped.

  The technique disclosed in this specification is characterized in that the position at which the movable electrode portion is fixed to the support substrate is brought closer to the position at which the fixed electrode portion is fixed to the support substrate. The technique disclosed in the present specification is characterized in that the fixed electrode portion is fixed to the support substrate via the beam portion in order to bring the both positions closer. The beam portion that supports the fixed electrode portion extends from the fixed electrode portion so as to approach a position where the movable electrode portion is fixed to the support substrate. Thereby, the position where the movable electrode part is fixed to the support substrate and the position where the fixed electrode part is fixed to the support substrate can be brought close to each other. If the positions of both are close, even if the support substrate is warped, the relative positional relationship between the movable electrode portion and the fixed electrode portion is maintained, and the influence of the warp of the support substrate is mitigated.

  The MEMS structure disclosed in the present specification includes a support substrate, a displacement part, a movable electrode part, a fixed electrode part, a first beam part, a first fixed part, a second beam part, and a second beam part. And a fixed portion. The displacement portion is supported by the support substrate via the first beam portion and is relatively displaceable with respect to the support substrate along at least the first direction. The first direction may be a direction perpendicular to the support substrate or a horizontal direction. The movable electrode portion is connected to the displacement portion and can be relatively displaced relative to the support substrate along at least the first direction depending on the displacement of the displacement portion. The movable electrode part may be directly connected to the displacement part, or may be indirectly connected via another member. For example, the movable electrode part may be connected to the displacement part via the first beam part. The fixed electrode portion is supported by the support substrate via the second beam portion, and is configured such that the distance from the movable electrode portion varies depending on the displacement of the movable electrode portion. It is desirable that the fixed electrode portion is prohibited from being displaced relative to the support substrate at least along the first direction. However, the fixed electrode portion may be displaced relative to the support substrate as long as the distance from the movable electrode portion varies depending on the displacement of the movable electrode portion. The first beam portion is fixed to the support substrate via the first fixing portion. The second beam portion is fixed to the support substrate via the second fixing portion. The first fixing part and the second fixing part may be a common fixing part. The distance between the first fixed part and the second fixed part is shorter than the distance between the first fixed part and the fixed electrode part. In the MEMS structure having this configuration, the movable electrode portion is fixed to the support substrate by the first fixed portion, and the fixed electrode portion is fixed to the support substrate by the second fixed portion. By using the second beam portion, the second fixed portion where the fixed electrode portion is fixed to the support substrate can be brought closer to the first fixed portion where the movable electrode portion is fixed to the support substrate, and the warp of the support substrate can be achieved. The effect of.

  In the MEMS structure disclosed in this specification, the fixed electrode portion may include a plurality of fixed electrode plates and a fixed electrode plate connecting portion that connects the plurality of fixed electrode plates. In this case, it is desirable that the second beam portion is connected to the fixed electrode plate connecting portion. In many conventional MEMS structures, the fixed electrode plate connecting portion of the fixed electrode portion is directly and rigidly fixed to the support substrate. In the MEMS structure disclosed in this specification, the fixed electrode plate connecting portion is connected to the second beam portion and floats with respect to the support substrate. The MEMS structure disclosed in the present specification has a different form from the conventional MEMS structure.

  In the MEMS structure disclosed in the present specification, it is desirable that the movable electrode portion and the fixed electrode portion are connected via the third beam portion. In this case, it is desirable that the third beam portion has a small spring constant in the first direction so that the distance between the movable electrode portion and the fixed electrode portion varies depending on the displacement of the movable electrode portion. Even if the third beam portion is provided between the movable electrode portion and the fixed electrode portion, the spring constant in the first direction of the third beam portion is configured to be small, so the distance between the movable electrode portion and the fixed electrode portion Can vary depending on the displacement of the movable electrode portion. On the other hand, when a force in a direction (including the rotation direction) different from the first direction is applied to the movable electrode portion, the force is also transmitted to the fixed electrode portion connected via the third beam portion. The For this reason, even if a force in a direction (including the rotation direction) different from the first direction is applied to the movable electrode portion and the movable electrode portion and the fixed electrode portion connected via the third beam portion, The relative positional relationship can be maintained.

  In the MEMS structure disclosed in the present specification, the first direction may be a direction perpendicular to the support substrate. In this case, the fixed electrode portion is separated from the support substrate by a separation groove that makes a round when observed from the first direction. Furthermore, the second beam portion extends beyond the separation groove when observed from the first direction. In the MEMS structure having this configuration, the displacement portion can be relatively displaced in the direction perpendicular to the support substrate, and the displacement portion itself is used as the movable electrode portion. The fixed electrode portion arranged to face the displacement portion is fixed to the surrounding support substrate by a second beam extending beyond the separation groove. According to the MEMS structure having this configuration, the separation groove is provided, so that the fixed electrode portion is floating with respect to the support substrate, and the influence of the warp of the support substrate is transmitted to the fixed electrode portion. can do.

  According to the MEMS structure disclosed in the present specification, the distance between the first fixed portion where the movable electrode portion is fixed to the support substrate and the second fixed portion where the fixed electrode portion is fixed to the support substrate may be reduced. Even if the support substrate is warped, the relative positional relationship between the movable electrode portion and the fixed electrode portion is maintained.

FIG. 1 is a schematic plan view of the acceleration sensor of the first embodiment. FIG. 2 is a sectional view taken along the line AA in FIG. FIG. 3 is a sectional view taken along line BB in FIG. FIG. 4 is a sectional view taken along the line CC in FIG. FIG. 5 illustrates a case where the semiconductor lower layer is deformed in the acceleration sensor of the first embodiment. FIG. 6 shows a schematic plan view of the acceleration sensor of the second embodiment. FIG. 7 is a schematic plan view of the acceleration sensor of the third embodiment. FIG. 8 is a cross-sectional view taken along the line AA in FIG. FIG. 9 is a sectional view taken along line BB in FIG. FIG. 10 is a sectional view taken along the line CC in FIG. FIG. 11 illustrates a case where the semiconductor lower layer is deformed in the acceleration sensor of the third embodiment. FIG. 12 is a schematic plan view of the acceleration sensor of the fourth embodiment. FIG. 13 is a schematic plan view of the acceleration sensor of the fifth embodiment. FIG. 14 is a sectional view taken along the line AA in FIG. FIG. 15 is a sectional view taken along line BB in FIG. FIG. 16 is a cross-sectional view taken along the line CC in FIG. FIG. 17 is a schematic plan view of the acceleration sensor of the sixth embodiment. FIG. 18 is a schematic plan view of the stage driving apparatus of the seventh embodiment. FIG. 19 is a schematic plan view of the angular velocity sensor of the eighth embodiment.

The features of the technology disclosed in this specification will be summarized.
(Feature 1) A MEMS structure includes a supporting substrate, a first fixing portion fixed to the supporting substrate, and a first beam portion extending from the first fixing portion and floating with respect to the supporting substrate. A displacement portion connected to the first beam portion and floating relative to the support substrate, a movable electrode portion connected to the displacement portion and floating relative to the support substrate, and a movable electrode A fixed electrode portion that is disposed opposite to the support portion and floats with respect to the support substrate, a second beam portion that extends from the fixed electrode portion and floats with respect to the support substrate, and a second beam And a second fixing part that is connected to the support substrate.
(Feature 2) In Feature 1, it is desirable that the second beam portion extends from the fixed electrode portion in a direction approaching the first fixed portion.
(Feature 3) In Feature 1, it is desirable that the first beam portion has a small spring constant in at least the first direction, and the second beam portion has a large spring constant in at least the first direction.
(Feature 4) In Feature 1, the displacement part itself may constitute the movable electrode part. In this case, it is desirable that the support substrate is used as the fixed electrode portion.
(Feature 5) In Feature 4, it is desirable that a part of the support substrate facing the displacement part is separated from the surrounding support substrate by the separation groove, and a part of the separated support substrate is used as the counter electrode part.

  Hereinafter, each example is illustrated with reference to drawings. In each embodiment, substantially the same components are denoted by the same reference numerals, and the description thereof may be omitted.

  The acceleration sensor 10 will be described with reference to FIGS. FIG. 1 is a schematic plan view of the acceleration sensor 10. FIG. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a cross-sectional view taken along line BB in FIG. FIG. 4 is a cross-sectional view taken along the line CC in FIG.

As shown in FIGS. 2 to 4, the acceleration sensor 10 is formed by processing the semiconductor lower layer 20, the insulating layer 30, and the semiconductor upper layer 40. The semiconductor lower layer 20 and the semiconductor upper layer 40 contain impurities at a high concentration and have conductivity. In one example, silicon single crystal (Si) is used as the material of the semiconductor lower layer 20 and the semiconductor upper layer 40. The insulating layer 30 electrically insulates the semiconductor lower layer 20 and the semiconductor upper layer 40. In one example, the material of the insulating layer 30 is silicon oxide (SiO ₂ ).

  As shown in FIG. 1, the acceleration sensor 10 includes a support substrate 21 and a displacement portion 41. The support substrate 21 is formed on the semiconductor lower layer 20. In this example, the semiconductor lower layer 20 is not processed, and the entire semiconductor lower layer 20 is used as the support substrate 21. The displacement part 41 is formed in the semiconductor upper layer 40. The insulating layer 30 between the displacement part 41 and the support substrate 21 is removed, and a space is formed between them. Thereby, the displacement part 41 is floating with respect to the support substrate 21. The displacement part 41 has a substantially square shape when viewed in plan (when observed from the z-axis direction). The displacement part 41 is supported by the support substrate 21 via the first beam part 42 provided near each of the four corners.

  The first beam portion 42 is formed in the semiconductor upper layer 40. The insulating layer 30 between the first beam portion 42 and the support substrate 21 is removed, and a space is formed between them. As a result, the first beam portion 42 is floating with respect to the support substrate 21. One end of the first beam portion 42 is connected to the vicinity of the corner portion of the side surface of the displacement portion 41, and the other end is connected to the first fixing portion 43. The first fixing portion 43 is a portion where the semiconductor lower layer 20, the insulating layer 30, and the semiconductor upper layer 40 are stacked. The first beam portion 42 extends linearly along the y-axis direction. The first beam portion 42 has a small spring constant in the x-axis direction and a large spring constant in the y-axis and z-axis directions. For this reason, the first beam portion 42 is easily elastically deformed in the x-axis direction and is hardly elastically deformed in the y-axis and the z-axis. Accordingly, the displacement portion 41 supported by the first beam portion 42 can be relatively displaced in the x-axis direction with respect to the support substrate 21 by the elastic deformation of the first beam portion 42 in the x-axis direction. is there.

  The acceleration sensor 10 further includes a detection electrode unit 50. The detection electrode unit 50 includes a movable electrode unit 51 and a fixed electrode unit 52 disposed to face the movable electrode unit 51. The movable electrode portion 51 includes a plurality of movable electrode plates 51a and a movable electrode plate coupling portion 51b that couples the plurality of movable electrode plates 51a. Both the movable electrode plate 51 a and the movable electrode plate connecting portion 51 b are formed in the semiconductor upper layer 40. The insulating layers between the movable electrode plate 51a and the support substrate 21 and between the movable electrode plate connecting portion 51b and the support substrate 21 are removed, and a space is formed between them. Thereby, the movable electrode plate 51 a and the movable electrode plate connecting portion 51 b are floating with respect to the support substrate 21. One end of the movable electrode plate 51a is connected to the movable electrode plate connecting portion 51b, the other end is a free end, and extends along the y-axis direction. One end of the movable electrode plate coupling portion 51b is connected to the displacement portion 41, the other end is configured as a free end, and extends along the x-axis direction. The movable electrode portion 51 can be displaced relative to the support substrate 21 in the x-axis direction following the displacement of the displacement portion 41 in the x-axis direction.

  The fixed electrode portion 52 includes a plurality of fixed electrode plates 52a and a fixed electrode plate connecting portion 52b that connects the plurality of fixed electrode plates 52a. Both the fixed electrode plate 52 a and the fixed electrode plate connecting portion 52 b are formed in the semiconductor upper layer 40. The insulating layer 30 between the fixed electrode plate 52a and the support substrate 21 and between the fixed electrode plate connecting portion 52b and the support substrate 21 is removed, and a space is formed between them. As a result, the fixed electrode plate 52 a and the fixed electrode plate connecting portion 52 b are floating with respect to the support substrate 21. One end of the fixed electrode plate 52a is connected to the fixed electrode plate connecting portion 52b, the other end is configured as a free end, and extends along the y-axis direction. The fixed electrode plate 52a and the movable electrode plate 51a face each other in the x-axis direction. The fixed electrode portion 52 is supported on the support substrate 21 via the second beam portion 53.

  The second beam portion 53 is formed in the semiconductor upper layer 40. The insulating layer 30 between the second beam portion 53 and the support substrate 21 is removed, and a space is formed between them. As a result, the second beam portion 53 is floating with respect to the support substrate 21. The second beam portion 53 has one end connected to the side surface of the fixed electrode plate connecting portion 52 b and the other end connected to the second fixed portion 54. The second fixing portion 54 is a portion where the semiconductor lower layer 20, the insulating layer 30, and the semiconductor upper layer 40 are stacked. The second beam portion 53 has a so-called cantilever form. The second beam portion 53 has a portion extending linearly along the y-axis direction and a portion extending linearly along the x-axis direction. The second beam portion 53 has a large spring constant in the x-axis, y-axis, and z-axis directions. For this reason, the second beam portion 53 is not easily elastically deformed in any of the x-axis, y-axis, and z-axis directions. Thereby, the fixed electrode portion 52 supported by the second beam portion 53 can serve as a fixed electrode.

  Next, the operation of the acceleration sensor 10 will be described. In the acceleration sensor 10, when acceleration in the x-axis direction is applied, the first beam portion 42 is elastically deformed, and the displacement portion 41 is relatively displaced with respect to the support substrate 21 in the x-axis direction. Following the displacement of the displacement portion 41, the movable electrode portion 51 is also displaced relative to the support substrate 21. On the other hand, the fixed electrode portion 52 functions as a fixed electrode because it is connected to the support substrate 21 by the second fixed portion 54 via the second beam portion 53 having a large spring constant in the x-axis direction. For this reason, the distance between the movable electrode plate 51a of the movable electrode portion 51 and the fixed electrode plate 52a of the fixed electrode portion 52 varies according to the acceleration applied in the x-axis direction.

  For example, if a capacitance detection circuit is connected between the first fixed portion 43 and the second fixed portion 54, the movable electrode plate 51a and the fixed electrode plate 52a that vary according to acceleration using the capacitance detection circuit. Can be measured. Thereby, the applied acceleration can be converted from the fluctuation of the capacitance.

  The acceleration sensor 10 is characterized in that the fixed electrode portion 52 is floating with respect to the support substrate 21 and is fixed to the support substrate 21 via the second beam portion 53. Further, the acceleration sensor 10 is characterized in that the second beam portion 53 extends from the fixed electrode portion 52 so as to approach the first fixed portion 43. More specifically, the second beam portion 53 has a portion extending in the x-axis direction and a portion extending in the y-axis direction, and thereby the x-axis direction from the fixed electrode portion 52 toward the first fixed portion 43. And both in the y-axis direction. As a result, in the acceleration sensor 10, the distance between the first fixed portion 43 and the second fixed portion 54 is configured to be shorter than the distance between the first fixed portion 43 and the fixed electrode portion 52.

  FIG. 5 illustrates a case where warpage occurs in the semiconductor lower layer 20. In the process of manufacturing the acceleration sensor 10, thermal stress at the time of manufacture may be applied to the semiconductor lower layer 20, which may cause warpage of the semiconductor lower layer 20. In this example, the semiconductor lower layer 20 is deformed around the y axis. As shown in FIG. 5, in the acceleration sensor 10, even when the semiconductor lower layer 20 is warped, the first fixed portion 43 and the fixed electrode portion 52 that fix the movable electrode portion 51 to the support substrate 21 are the support substrate 21. Since the distance between the second fixed portions 54 fixed to the short is configured to be short, the relative positional relationship between the movable electrode portion 51 and the fixed electrode portion 52 is maintained. More specifically, since the distance between the first fixed portion 43 and the second fixed portion 54 is close to the x-axis direction, even if the semiconductor lower layer 20 is warped around the y-axis, the movable electrode portion 51 is fixed. The relative positional relationship of the electrode part 52 is maintained. In addition, since the distance between the first fixed portion 43 and the second fixed portion 54 is close to the y-axis direction, even if the semiconductor lower layer 20 warps around the x-axis, the movable electrode portion 51 and the fixed electrode portion 52. The relative positional relationship is maintained. Note that the relative positional relationship between the movable electrode portion 51 and the fixed electrode portion 52 can be further increased by making the length of the first beam portion 42 in the y-axis direction substantially equal to the length of the second beam portion 53 in the y-axis direction. Can be maintained. As described above, in the acceleration sensor 10, since the distance between the first fixed portion 43 and the second fixed portion 54 is close, the capacitance between the movable electrode portion 51 and the fixed electrode portion 52 due to the warp of the semiconductor lower layer 20. The change can be relaxed, and stable characteristics can be obtained with respect to the warp of the support substrate 21.

  The acceleration sensor 100 will be described with reference to FIG. The acceleration sensor 100 includes a pair of x-axis detection electrode portions 50A and 50C arranged along the x-axis direction and a pair of y-axis detection electrode portions 50B and 50D arranged along the y-axis direction. It is characterized by being. The x-axis detection electrode portions 50A and 50C face each other along the x-axis direction with the displacement portion 41 interposed therebetween. The y-axis detection electrode portions 50B and 50D face each other along the y-axis direction with the displacement portion 41 interposed therebetween. These detection electrode portions 50A, 50B, 50C, and 50D include a movable electrode portion 51 and a fixed electrode portion 52, as in the first embodiment. Here, the fixed electrode portion 52 of the present embodiment is different from the first embodiment (so-called cantilever beam) in that it is supported by a pair of second beam portions 53 (so-called cantilever beams). However, in other respects, these detection electrode portions 50A, 50B, 50C, and 50D have substantially the same form as the detection electrode portion 50 of the first embodiment.

  The acceleration sensor 100 further includes an x-axis first beam portion 142 that is provided between the x-axis detection electrode portions 50A and 50C and the displacement portion 41 and supports the displacement portion 41 with respect to the support substrate 21, and a y-axis detection. A y-axis first beam portion 144 that is provided between the electrode portions 50 </ b> B and 50 </ b> D and the displacement portion 41 and supports the displacement portion 41 with respect to the support substrate 21 is provided.

  The x-axis first beam portion 142 is formed in the semiconductor upper layer 40. The insulating layer 30 between the x-axis first beam portion 142 and the support substrate 21 is removed, and a space is formed between them. As a result, the x-axis first beam portion 142 is floating with respect to the support substrate 21. The x-axis first beam portion 142 includes an x-spring beam 142a, an x-axis plate 142b, and a y-spring beam 142c. The x spring beam 142a has a small spring constant in the x-axis direction and a large spring constant in the y-axis and z-axis directions. For this reason, the x spring beam 142a is easily elastically deformed in the x axis direction, and is not easily elastically deformed in the y axis direction and the z axis direction. The y spring beam 142c has a small spring constant in the y-axis direction and a large spring constant in the x-axis and z-axis directions. For this reason, the y spring beam 142c is easily elastically deformed in the y-axis direction, and is not easily elastically deformed in the x-axis and z-axis directions. The x-axis plate 142b connects both the x-spring beam 142a and the y-spring beam 142c, and has a large spring constant in the x-axis, y-axis, and z-axis directions. For this reason, the x-axis plate 142b does not elastically deform in any of the x-axis, y-axis, and z-axis directions. The movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C are directly connected to the x-axis plate 142b and indirectly connected to the displacement portion 41 via the x-axis plate 142b and the y spring beam 142c. Yes.

  The y-axis first beam portion 144 is formed in the semiconductor upper layer 40. The insulating layer 30 between the y-axis first beam portion 144 and the support substrate 21 is removed, and a space is formed between them. The y-axis first beam portion 144 is floating with respect to the support substrate 21. The y-axis first beam portion 144 includes a y-spring beam 144a, a y-axis plate 144b, and an x-spring beam 144c. The y spring beam 144a has a small spring constant in the y-axis direction and a large spring constant in the x-axis and z-axis directions. For this reason, the y spring beam 144a is easily elastically deformed in the y-axis direction and is not easily elastically deformed in the x-axis and z-axis directions. The x spring beam 144c has a small spring constant in the x-axis direction and a large spring constant in the y-axis and z-axis directions. For this reason, the x spring beam 144c is easily elastically deformed in the x-axis direction and is not easily elastically deformed in the y-axis and z-axis directions. The y-axis plate 144b connects both the y-spring beam 144a and the x-spring beam 144c, and has a large spring constant in the x-axis, y-axis, and z-axis directions. For this reason, the y-axis plate 144b does not elastically deform in any of the x-axis, y-axis, and z-axis directions. The movable electrode portions 51 of the y-axis detection electrode portions 50B and 50D are directly connected to the y-axis plate 144b and indirectly connected to the displacement portion 41 via the y-axis plate 144b and the x spring beam 144c. Yes.

  Next, the operation of the acceleration sensor 100 will be described. In the acceleration sensor 100, when acceleration in the x-axis direction is applied, both the x-spring beam 142a of the x-axis first beam portion 142 and the x-spring beam 144c of the y-axis first beam portion 144 are elastically deformed, and the displacement portion 41 is It is displaced relative to the support substrate 21 in the x-axis direction. Following the displacement of the displacement portion 41, the movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C are also displaced relative to the support substrate 21. On the other hand, since the fixed electrode portion 52 of the x-axis detection electrode portions 50A and 50C is supported by the second beam portion 53 having a large spring constant in the x-axis direction, it can serve as an x-axis fixed electrode. Thereby, the acceleration sensor 100 can detect acceleration in the x-axis direction.

  Furthermore, in the acceleration sensor 100, when acceleration in the y-axis direction is applied, both the y-spring beam 142c of the x-axis first beam portion 142 and the y-spring beam 144a of the y-axis first beam portion 144 are elastically deformed, and the displacement portion 41 is displaced relative to the support substrate 21 in the y-axis direction. Following the displacement of the displacement portion 41, the movable electrode portions 51 of the y-axis detection electrode portions 50B and 50D are also relatively displaced with respect to the support substrate 21. On the other hand, since the fixed electrode portion 52 of the y-axis detection electrode portions 50B and 50D is supported by the second beam portion 53 having a large spring constant in the y-axis direction, it can serve as a y-axis fixed electrode. Thereby, the acceleration sensor 100 can detect acceleration in the y-axis direction. The acceleration sensor 100 can detect two-axis accelerations of an x-axis and a y-axis.

  Also in the acceleration sensor 100, the fixed electrode portions 52 of the x-axis detection electrode portions 50 </ b> A and 50 </ b> C are floating with respect to the support substrate 21 and are fixed to the support substrate 21 via the second beam portion 53. Further, the fixed electrode portions 52 of the y-axis detection electrode portions 50 </ b> B and 50 </ b> D are also floating with respect to the support substrate 21 and are fixed to the support substrate 21 via the second beam portion 53. Using this technique, the acceleration sensor 100 is also configured such that the distance between the first fixed portion 43 and the second fixed portion 54 is shorter than the distance between the first fixed portion 43 and the fixed electrode portion 52. Thereby, in the acceleration sensor 100, the relative positional relationship between the movable electrode part 51 and the fixed electrode part 52 can be maintained against the warp of the semiconductor lower layer 20, and a stable characteristic against the warp can be obtained. Further, in the acceleration sensor 100, the fixing method of the second beam portion 53 is constituted by both ends like the fixing method of the first beam portions 142 and 144. For this reason, when the support substrate 21 is warped around the x axis or the y axis, the first beam portions 142 and 144 and the second beam portion 53 are curved in the same shape, and the positional relationship between the two is further maintained. Can do.

  The acceleration sensor 200 will be described with reference to FIGS. FIG. 7 shows a schematic plan view of the acceleration sensor 200. FIG. 8 is a cross-sectional view taken along line AA in FIG. FIG. 9 shows a cross-sectional view along the line BB in FIG. FIG. 10 is a sectional view taken along the line CC in FIG.

  The acceleration sensor 200 includes a pair of x-axis detection electrode portions 50A and 50C arranged along the x-axis direction. These x-axis detection electrode portions 50A and 50C have substantially the same form as the x-axis detection electrode portions 50A and 50C of the second embodiment.

  The acceleration sensor 200 further includes an x-axis first beam portion 242 that is provided between the x-axis detection electrode portions 50A and 50C and the displacement portion 41 and supports the displacement portion 41 with respect to the support substrate 21. It is characterized by. The x-axis first beam portion 242 is different from the x-axis first beam portion 142 of the second embodiment in the direction of elastic deformation.

  The x-axis first beam portion 242 is formed in the semiconductor upper layer 40. The insulating layer 30 between the x-axis first beam portion 242 and the support substrate 21 is removed, and a space is formed between them. Thereby, the x-axis first beam portion 242 is floated with respect to the support substrate 21. The x-axis first beam portion 242 includes an x-spring beam 242a, an x-axis plate 242b, and a z-spring beam 242c. The x spring beam 242a has a small spring constant in the x-axis direction and a large spring constant in the y-axis and z-axis directions. For this reason, the x spring beam 242a is easily elastically deformed in the x-axis direction and is not easily elastically deformed in the y-axis and z-axis directions. The z spring beam 242c has a small spring constant in the z-axis direction and a large spring constant in the x-axis and y-axis directions. For this reason, the z spring beam 242c is easily elastically deformed in the z-axis direction and is not easily elastically deformed in the x-axis and y-axis directions. The x-axis plate 242b connects both the x spring beam 242a and the z spring beam 242c, and has a large spring constant in the x-axis, y-axis, and z-axis directions. For this reason, the x-axis plate 242b is not easily elastically deformed in any of the x-axis, y-axis, and z-axis directions. The movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C are directly connected to the x-axis plate 242b and indirectly connected to the displacement portion 41 via the x-axis plate 242b and the z spring beam 242c. Yes.

  The acceleration sensor 200 further includes a z-axis detection electrode unit 50E. The z-axis detection electrode part 50E is composed of a displacement part 41 used as a movable electrode part and a z-axis fixed electrode plate 222 used as a fixed electrode part. The z-axis fixed electrode plate 222 is formed in the semiconductor lower layer 20. The insulating layer 30 between the z-axis fixed electrode plate 222 and the displacement portion 41 is removed, and a space is formed between them. The z-axis fixed electrode plate 222 is separated from the support substrate 21 by a separation groove 22 that makes a round when observed from the z-axis direction. Thereby, the z-axis fixed electrode plate 222 is floating with respect to the support substrate 21. The z-axis fixed electrode plate 222 is supported on the support substrate 21 via the z-axis second beam portion 245. The z-axis fixed electrode plate 222 overlaps with the displacement portion 41 and is formed wider than the displacement portion 41 when observed from the z-axis direction.

  The z-axis second beam portion 245 is formed in the semiconductor upper layer 40. The insulating layer 30 between the z-axis second beam portion 245 and the support substrate 21 and the z-axis second beam portion 245 and the z-axis fixed electrode plate 222 is removed, and a space is formed therebetween. As a result, the z-axis second beam portion 245 floats with respect to the support substrate 21 and the z-axis fixed electrode plate 222. One end of the z-axis second beam portion 245 is connected to the z-axis fixed electrode plate 222 via the z-axis fixed electrode plate fixing portion 244, and the other end is connected to the support substrate fixing portion 246 (the second fixing portion of the second fixing portion). The support substrate 21 is connected via an example). The z-axis fixed electrode plate fixing portion 244 and the support substrate fixing portion 246 are portions where the semiconductor lower layer 20, the insulating layer 30, and the semiconductor upper layer 40 are stacked. The z-axis second beam portion 245 has a portion extending linearly along the y-axis direction and a portion extending linearly along the x-axis direction. The z-axis second beam portion 245 has a large spring constant in the x-axis, y-axis, and z-axis directions. For this reason, the z-axis second beam portion 245 is hardly elastically deformed in any of the x-axis, y-axis, and z-axis directions. Accordingly, the z-axis fixed electrode plate 222 supported by the z-axis second beam portion 245 can serve as a z-axis fixed electrode.

  Next, the operation of the acceleration sensor 200 will be described. In the acceleration sensor 200, when acceleration in the x-axis direction is applied, the x spring beam 242 a of the x-axis first beam portion 242 is elastically deformed, and the displacement portion 41 is relatively displaced with respect to the support substrate 21 in the x-axis direction. Following the displacement of the displacement portion 41, the movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C are also displaced relative to the support substrate 21. On the other hand, since the fixed electrode portion 52 of the x-axis detection electrode portions 50A and 50C is supported by the second beam portion 53 having a large spring constant in the x-axis direction, it can serve as an x-axis fixed electrode. Thereby, the acceleration sensor 200 can detect the acceleration in the x-axis direction. It is desirable that the displacement width of the displacement portion 41 in the x-axis direction does not exceed the existence range of the z-axis fixed electrode plate 222 when observed from the z-axis direction. Thereby, even if the displacement part 41 displaces to a x-axis direction, the change of an electrostatic capacitance does not generate | occur | produce in the z-axis detection electrode part 50E.

  Further, in the acceleration sensor 200, when acceleration in the z-axis direction is applied, the z spring beam 242 c of the x-axis first beam portion 242 is elastically deformed, and the displacement portion 41 is relatively displaced in the z-axis direction with respect to the support substrate 21. . On the other hand, since the z-axis fixed electrode plate 222 is supported by the z-axis second beam portion 245 having a large spring constant in the z-axis direction, it can serve as a z-axis fixed electrode. Thereby, the acceleration sensor 200 can detect the acceleration in the z-axis direction. The acceleration sensor 200 can detect two-axis accelerations of the x axis and the z axis.

  The acceleration sensor 200 is characterized in that the z-axis fixed electrode plate 222 floats with respect to the support substrate 21 and is supported by the support substrate 21 via the z-axis second beam portion 245. Further, the acceleration sensor 200 is characterized in that the z-axis second beam portion 245 extends from the z-axis fixed electrode portion plate 222 so as to approach the first fixed portion 43. More specifically, the z-axis second beam portion 245 has a portion extending in the x-axis direction and a portion extending in the y-axis direction, whereby the z-axis fixed electrode plate 222 is directed to the first fixing portion 43. Therefore, they are close in both the x-axis direction and the y-axis direction. As a result, the acceleration sensor 200 is configured such that the distance between the first fixing portion 43 and the support substrate fixing portion 246 is shorter than the distance between the first fixing portion 43 and the z-axis fixed electrode plate 222.

  FIG. 11 illustrates a case where warpage occurs in the semiconductor lower layer 20. In the process of manufacturing the acceleration sensor 200, thermal stress during manufacturing may be applied to the semiconductor lower layer 20, which may cause warpage of the semiconductor lower layer 20. In this example, the semiconductor lower layer 20 is deformed around the y axis. As shown in FIG. 5, in the acceleration sensor 200, even if the semiconductor lower layer 20 is warped, the z-axis fixed electrode plate 222 is separated by the separation groove 22. Transmission to the fixed shaft electrode plate 222 is mitigated. Further, in the acceleration sensor 200, since the distance between the first fixing portion 43 and the support substrate fixing portion 246 is close, even if warpage occurs in the semiconductor lower layer 20, the semiconductor lower layer 20 is resisted against warpage. The relative positional relationship between the displacement portion 41 and the z-axis fixed electrode plate 222 can be maintained. Therefore, the capacitance change between the displacement portion 41 and the z-axis fixed electrode plate 222 due to the warp of the support substrate 21 is small, and stable acceleration detection is possible.

  The acceleration sensor 300 will be described with reference to FIG. The acceleration sensor 300 includes a pair of x-axis detection electrode portions 50A and 50C, a pair of y-axis detection electrode portions 50B and 50D, and a z-axis detection electrode portion 50E. The x-axis detection electrode portions 50A and 50C and the y-axis detection electrode portions 50B and 50D have substantially the same form as the x-axis detection electrode portions 50A and 50C and the y-axis detection electrode portions 50B and 50D of the second embodiment. ing. The z-axis detection electrode unit 50E has substantially the same form as the z-axis detection electrode unit 50E of the third embodiment.

  The acceleration sensor 300 further includes an x-axis first beam portion 342 that is provided between the x-axis detection electrode portions 50A and 50C and the displacement portion 41 and supports the displacement portion 41 with respect to the support substrate 21, and a y-axis detection. A y-axis first beam portion 344 provided between the electrode portions 50B and 50D and the displacement portion 41 and supporting the displacement portion 41 with respect to the support substrate 21 and a z-axis fixed electrode plate 222 with respect to the support substrate 21. It is characterized by having a z-axis second beam portion 245 to be supported. The z-axis second beam portion 245 has a form substantially common to the z-axis second beam portion 245 of the third embodiment.

  The x-axis first beam portion 342 is formed in the semiconductor upper layer 40. The insulating layer 30 between the x-axis first beam portion 342 and the support substrate 21 is removed, and a space is formed between them. As a result, the x-axis first beam portion 342 is floating with respect to the support substrate 21. The x-axis first beam portion 342 includes an x-spring beam 342a, an x-axis plate 342b, and a yz spring beam 342c. The x spring beam 342a has a small spring constant in the x-axis direction and a large spring constant in the y-axis and z-axis directions. For this reason, the x spring beam 342a is easily elastically deformed in the x axis direction, and is not easily elastically deformed in the y axis and the z axis. The yz spring beam 342c has a small spring constant in the y-axis and z-axis directions and a large spring constant in the x-axis direction. For this reason, the yz spring beam 342c is easily elastically deformed in the y-axis and z-axis directions, and is hardly elastically deformed in the x-axis direction. The x-axis plate 342b connects both the x-spring beam 342a and the yz-spring beam 342c, and has a large spring constant in the x-axis, y-axis, and z-axis directions. For this reason, the x-axis plate 342b is not easily elastically deformed in any of the x-axis, y-axis, and z-axis directions. The movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C are directly connected to the x-axis plate 342b and indirectly connected to the displacement portion 41 via the x-axis plate 342b and the yz spring beam 342c. Yes.

  The y-axis first beam portion 344 is formed in the semiconductor upper layer 40. The insulating layer 30 between the y-axis first beam portion 344 and the support substrate 21 is removed, and a space is formed between them. As a result, the y-axis first beam portion 344 is floating with respect to the support substrate 21. The y-axis first beam portion 344 includes a y-spring beam 344a, a y-axis plate 344b, and an xz spring beam 344c. The y spring beam 344a has a small spring constant in the y-axis direction and a large spring constant in the x-axis and z-axis directions. For this reason, the y spring beam 344a is elastically deformed in the y-axis direction and is not elastically deformed in the x-axis and z-axis directions. The xz spring beam 344c has a small spring constant in the x-axis and z-axis directions and a large spring constant in the y-axis direction. For this reason, the xz spring beam 344c is elastically deformed in the x-axis and z-axis directions and is hardly elastically deformed in the y-axis direction. The y-axis plate 344b connects both the y-spring beam 344a and the xz-spring beam 344c and has a large spring constant in the x-axis, y-axis, and z-axis directions. For this reason, the y-axis plate 344b is not easily elastically deformed in any of the x-axis, y-axis, and z-axis directions. The movable electrode portions 51 of the y-axis detection electrode portions 50B and 50D are directly connected to the y-axis plate 344b and indirectly connected to the displacement portion 41 via the y-axis plate 344b and the xz spring beam 344c. Yes.

  Next, the operation of the acceleration sensor 300 will be described. In the acceleration sensor 300, when acceleration in the x-axis direction is applied, the x-spring beam 342a of the x-axis first beam portion 342 and the xz spring beam 344c of the y-axis first beam portion 344 are elastically deformed, and the displacement portion 41 is supported by the support substrate. 21 is relatively displaced in the x-axis direction. Following the displacement of the displacement portion 41, the movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C are also displaced relative to the support substrate 21. On the other hand, since the fixed electrode portion 52 of the x-axis detection electrode portions 50A and 50C is supported by the second beam portion 53 having a large spring constant in the x-axis direction, it can serve as an x-axis fixed electrode. Thereby, the acceleration sensor 100 can detect acceleration in the x-axis direction.

  In the acceleration sensor 300, when acceleration in the y-axis direction is applied, the yz spring beam 342c of the x-axis first beam portion 342 and the y spring beam 344a of the y-axis first beam portion 344 are elastically deformed, and the displacement portion 41 is It is displaced relative to the support substrate 21 in the y-axis direction. Following the displacement of the displacement portion 41, the movable electrode portions 51 of the y-axis detection electrode portions 50B and 50D are also relatively displaced with respect to the support substrate 21. On the other hand, since the fixed electrode portion 52 of the y-axis detection electrode portions 50B and 50D is supported by the second beam portion 53 having a large spring constant in the y-axis direction, it can serve as a y-axis fixed electrode. Thereby, the acceleration sensor 300 can detect acceleration in the y-axis direction.

  Further, in the acceleration sensor 300, when acceleration in the z-axis direction is applied, the yz spring beam 342c of the x-axis first beam portion 342 and the xz spring beam 344c of the y-axis first beam portion 344 are elastically deformed, and the displacement portion 41 is It is displaced relative to the support substrate 21 in the z-axis direction. On the other hand, since the z-axis fixed electrode plate 222 is supported by the z-axis second beam portion 245 having a large spring constant in the z-axis direction, it can serve as a z-axis fixed electrode. Thereby, the acceleration sensor 300 can detect acceleration in the z-axis direction. The acceleration sensor 300 can detect three-axis accelerations of the x axis, the y axis, and the z axis.

  The acceleration sensor 400 will be described with reference to FIGS. FIG. 13 shows a schematic plan view of the acceleration sensor 400. FIG. 14 is a cross-sectional view taken along line AA in FIG. FIG. 15 is a cross-sectional view taken along line BB in FIG. FIG. 16 is a cross-sectional view taken along the line CC in FIG.

  The acceleration sensor 400 includes a pair of x-axis detection electrode portions 50A and 50C and a z-axis detection electrode portion 50E. The x-axis detection electrode portions 50A and 50C have substantially the same form as the x-axis detection electrode portions 50A and 50C of the second embodiment, although the fixed electrode plate connecting portion of the fixed electrode portion 52 is configured to be wide. I have. The z-axis detection electrode unit 50E has substantially the same form as the z-axis detection electrode unit 50E of the third embodiment.

  The acceleration sensor 400 further includes an x-axis first beam portion 242 that is provided between the x-axis detection electrode portions 50A and 50C and the displacement portion 41 and supports the displacement portion 41 with respect to the support substrate 21, and a z-axis fixed. A z-axis second beam portion 245 that supports the electrode plate 222 with respect to the support substrate 21 is provided. The x-axis first beam portion 242 has a form substantially common to the x-axis first beam portion 242 of the third embodiment. The z-axis second beam portion 245 has a form substantially common to the z-axis second beam portion 245 of the third embodiment.

  The acceleration sensor 400 further includes a connecting portion 410 provided between the movable electrode portion 51 and the fixed electrode portion 52 of the x-axis detection electrode portions 50A and 50C. The connecting portion 410 has three projecting portions 411, 412, 413 and third beam portions 414, 415. The protrusions 411, 412, and 413 are portions where the semiconductor lower layer 20, the insulating layer 30, and the semiconductor upper layer 40 are stacked. The projecting portions 411 and 413 project from the x-axis plate 242b of the x-axis first beam portion 242 in the x-axis direction, and the movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C are connected to the tips thereof. The protruding portion 412 protrudes in the x-axis direction from the fixed electrode plate connecting portion 52 b of the fixed electrode portion 52. The third beam portions 414 and 415 are formed in the semiconductor lower layer 20. The third beam portion 414 connects the protruding portion 411 and the protruding portion 412. The third beam portion 415 connects the protruding portion 412 and the protruding portion 413. Thereby, the connection part 410 has connected between the movable electrode part 51 and the fixed electrode part 52 of x-axis detection electrode part 50A, 50C. The third beam portions 414 and 415 have small spring constants in the x-axis direction and large spring constants in the y-axis and z-axis directions. For this reason, the third beam portions 414 and 415 are elastically deformed in the x-axis and are not elastically deformed in the y-axis and z-axis directions.

  In the acceleration sensor 400, the second beam portion 453 that supports the fixed electrode portion 52 of the x-axis detection electrode portions 50A and 50C has a small spring constant in the z-axis direction and a large spring constant in the x-axis and y-axis directions. It is characterized by. For this reason, the second beam portion 453 is easily elastically deformed in the z-axis and hardly elastically deformed in the x-axis and y-axis directions.

  Next, the operation of the acceleration sensor 400 will be described. In the acceleration sensor 400, when acceleration in the x-axis direction is applied, the x spring beam 242 a of the x-axis first beam portion 242 is elastically deformed, and the displacement portion 41 is relatively displaced with respect to the support substrate 21 in the x-axis direction. Following the displacement of the displacement portion 41, the movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C are also displaced relative to the support substrate 21. On the other hand, since the fixed electrode portion 52 of the x-axis detection electrode portions 50A and 50C is supported by the second beam portion 453 having a large spring constant in the x-axis direction, it can serve as an x-axis fixed electrode. Since the third beam portions 414 and 415 of the connecting portion 410 have a small spring constant in the x-axis direction, the translational force in the x-axis direction of the displacement portion 41 is not transmitted to the fixed electrode portion 52. Thereby, the acceleration sensor 400 can detect acceleration in the x-axis direction.

  Further, in the acceleration sensor 400, when acceleration in the z-axis direction is applied, the z spring beam 242c of the x-axis first beam portion 242 is elastically deformed, and the displacement portion 41 is relatively displaced in the z-axis direction with respect to the support substrate 21. . On the other hand, since the z-axis fixed electrode plate 222 is supported by the z-axis second beam portion 245 having a large spring constant in the z-axis direction, it can serve as a z-axis control k-low electrode. Thereby, the acceleration sensor 400 can detect acceleration in the z-axis direction. The acceleration sensor 400 can detect two-axis accelerations of the x axis and the z axis.

  In the acceleration sensor 400, when the displacement portion 41 is displaced in the z-axis direction, a rotational force about the y-axis is applied to the x-axis plate 242b of the x-axis first beam portion 242 via the z spring beam 242c. For this reason, the movable electrode portions 51 of the x-axis detection electrode portions 50A and 50C connected to the x-axis plate 242b also receive a rotational force around the y-axis. This rotational force is transmitted to the fixed electrode portions 52 of the x-axis detection electrode portions 50A and 50C via the third beam portions 414 and 415. Since the fixed electrode portion 52 of the x-axis detection electrode portions 50A and 50C is supported by the second beam portion 453 having a small spring constant in the z-axis direction, it can rotate around the y-axis. For this reason, when both the movable electrode part 51 and the fixed electrode part 52 rotate around the y-axis, the relative positional relationship is further maintained, and stable characteristics can be obtained. Further, even when the displacement part 41 is displaced in the z-axis direction, the movable electrode part 51 and the fixed electrode part 52 are rotated relative to each other by rotating both the movable electrode part 51 and the fixed electrode part 52 around the y-axis. The positional relationship is maintained, and the sensitivity of other axes can be reduced. Since the third beam portions 414 and 415 are composed of two or more parallel beams, the rotational rigidity around the y-axis can be increased, and the rotation angles of the third beam portions 414 and 415 can be kept equal. The relative positional relationship between the movable electrode portion 51 and the fixed electrode portion 52 can be more effectively maintained.

  The acceleration sensor 500 will be described with reference to FIG. The acceleration sensor 500 includes a pair of x-axis detection electrode portions 50A and 50C, a pair of y-axis detection electrode portions 50B and 50D, and a z-axis detection electrode portion 50E. The x-axis detection electrode portions 50A and 50C and the y-axis detection electrode portions 50B and 50D have substantially the same form as the x-axis detection electrode portions 50A and 50C and the y-axis detection electrode portions 50B and 50D of the second embodiment. ing. The z-axis detection electrode unit 50E has substantially the same form as the z-axis detection electrode unit 50E of the third embodiment.

  The acceleration sensor 500 further includes an x-axis first beam portion 342 that is provided between the x-axis detection electrode portions 50A and 50C and the displacement portion 41 and supports the displacement portion 41 with respect to the support substrate 21, and a y-axis detection. A y-axis first beam portion 344 provided between the electrode portions 50B and 50D and the displacement portion 41 and supporting the displacement portion 41 with respect to the support substrate 21 and a z-axis fixed electrode plate 222 with respect to the support substrate 21. It is characterized by having a z-axis second beam portion 245 to be supported. The x-axis first beam portion 342, the y-axis first beam portion 344, and the z-axis second beam portion 245 are respectively the x-axis first beam portion 342, the y-axis first beam portion 344, and the z-axis number of the fourth embodiment. The two beam portions 245 have substantially the same form.

  The acceleration sensor 500 further includes a connecting portion 410 provided between the detection electrode portions 50A, 50B, 50C, and 50D and the first beam portions 342 and 344. The connection part 410 has a form substantially common to the connection part 410 of the fifth embodiment.

  The acceleration sensor 500 can reduce both the influence of the warp of the semiconductor lower layer 20 and the influence of the rotational force generated when the displacement portion 41 is displaced in the z-axis direction, and can detect the acceleration in the triaxial direction.

  The stage driving apparatus 600 will be described with reference to FIG. The stage driving device 600 is used as an actuator that drives the displacement unit 41 in the x-axis direction. The stage driving device 600 includes a support substrate 21, a displacement portion 41 (stage), and a pair of driving electrode portions 60A and 60B. The support substrate 21, the displacement portion 41, the first beam portion 42, and the first fixing portion 43 are substantially the same as the support substrate 21, the displacement portion 41, the first beam portion 42, and the first fixing portion 43 of the first embodiment. It has the form.

  The pair of drive electrode portions 60A and 60B face each other along the x-axis direction with the displacement portion 41 interposed therebetween. In one example, the drive electrode portion 60 </ b> A detects the amount of displacement of the displacement portion 41, and the drive electrode portion 60 </ b> B applies a driving force to the displacement portion 41. Based on the detection result detected by the drive electrode unit 60A, the drive electrode unit 60B is controlled, and the displacement unit 41 is accurately driven to the target position. Alternatively, the drive electrode unit 60A may apply a driving force to the displacement unit 41, and the drive electrode unit 60B may detect the displacement amount of the displacement unit 41.

  The drive electrode portions 60 </ b> A and 60 </ b> B have a movable electrode portion 651 and a fixed electrode portion 652 disposed to face the movable electrode portion 651. The movable electrode portion 651 has a plurality of movable electrode plates 651a. One end of the movable electrode plate 651a is connected to the displacement portion 41, the other end is a free end, and extends along the x-axis direction.

  The fixed electrode portion 652 includes a plurality of fixed electrode plates 652a and a fixed electrode plate connecting portion 652b that connects the plurality of fixed electrode plates 652a. One end of the fixed electrode plate 652a is connected to the fixed electrode plate coupling portion 652b, the other end is configured as a free end, and extends along the x-axis direction. The fixed electrode plate 652a and the movable electrode plate 651a face each other in the y-axis direction. The fixed electrode portion 652 is supported on the support substrate 21 via the second beam portion 653.

  The second beam portion 653 has one end connected to the fixed electrode plate connecting portion 652 b and the other end connected to the second fixed portion 654. The second beam portion 653 has a portion extending linearly along the y-axis direction and a portion extending linearly along the x-axis direction. The second beam portion 653 has a large spring constant in the x-axis, y-axis, and z-axis directions. For this reason, the second beam portion 653 is hardly elastically deformed in any of the x-axis, y-axis, and z-axis directions. Accordingly, the fixed electrode portion 652 supported by the second beam portion 653 can serve as a fixed electrode.

  Next, the operation of the stage driving device 600 will be described. In the stage drive device 600, a capacitance detection circuit is connected between the movable electrode plate 651a and the fixed electrode plate 652a of the drive electrode portion 60A, and an amplitude control circuit is connected between the movable electrode plate 651a and the fixed electrode plate 652a of the drive electrode portion 60B. A drive signal generation circuit is connected via When a DC voltage is applied from the drive signal generation circuit via the amplitude control circuit, an electrostatic attractive force is generated between the movable electrode plate 651a and the fixed electrode plate 652a of the drive electrode portion 60B, and the displacement portion 41 is moved in the x-axis direction. To drive. The drive electrode portion 60A detects the amount of displacement of the displacement portion 41 in the x-axis direction from the change in capacitance between the movable electrode plate 651a and the fixed electrode plate 652a using a capacitance detection circuit. The detection result of the capacitance detection circuit is fed back to the drive signal generation circuit, and the drive signal generation circuit generates a drive signal raw based on the detection result. The amplitude control circuit controls the DC voltage based on the drive signal so that the displacement amount of the displacement unit 41 becomes a target value. With these configurations, the stage driving device 600 can accurately drive the displacement unit 41 to the target position.

  The stage driving device 600 is characterized in that the fixed electrode portion 652 floats with respect to the support substrate 21 and is fixed to the support substrate 21 via the second beam portion 653. Further, the stage driving device 600 is characterized in that the second beam portion 653 extends from the fixed electrode portion 652 so as to approach the first fixed portion 43. More specifically, the second beam portion 653 has a portion extending in the x-axis direction and a portion extending in the y-axis direction, and thereby the x-axis direction from the fixed electrode portion 652 toward the first fixed portion 43. And both in the y-axis direction. As a result, in the stage driving device 600, the distance between the first fixed portion 43 and the second fixed portion 54 is configured to be shorter than the distance between the first fixed portion 43 and the fixed electrode portion 52.

  As a result, in the stage driving apparatus 600, even if the semiconductor lower layer 20 is warped, the first fixed portion 43 and the fixed electrode portion 652 where the movable electrode portion 651 is fixed to the support substrate 21 are fixed to the support substrate 21. Since the distance between the second fixed portions 654 is configured to be short, in the stage driving apparatus 600, the relative positional relationship between the movable electrode portion 651 and the fixed electrode portion 652 is maintained. In the stage driving device 600, since the distance between the first fixing portion 43 and the second fixing portion 654 is close, the influence of the warp of the semiconductor lower layer 20 can be mitigated. Therefore, since the electrodes of the movable electrode portion 651 and the fixed electrode portion 652 do not deviate, stable driving in the x-axis direction and stable displacement detection are possible, and stable stage driving can be realized.

  The angular velocity sensor 700 will be described with reference to FIG. The angular velocity sensor 700 includes a pair of detection electrode portions 50B and 50D. The detection electrode portions 50B and 50D have substantially the same form as the y-axis detection electrode portions 50B and 50D of the second embodiment.

  The angular velocity sensor 700 further includes a pair of drive electrode portions 60A and 60B. The drive electrode portions 60A and 60B have substantially the same form as the drive electrode portions 60A and 60B of the sixth embodiment.

  The angular velocity sensor 700 further includes an x-axis first beam portion 142 that is provided between the drive electrode portions 60A and 60B and the displacement portion 41 and supports the displacement portion 41 with respect to the support substrate 21. It is a feature. The x-axis first beam portion 142 has a feature that is substantially common to the x-axis first beam portion 142 of the second embodiment. In the angular velocity sensor 700, the movable electrode plates 651a of the drive electrode portions 60A and 60B are connected to the x-axis plate 142b of the first x-axis beam portion 142.

  Next, the operation of the angular velocity sensor 700 will be described. In the angular velocity sensor 700, a capacitance detection circuit is connected to the drive electrode unit 60A, and a self-excited circuit is connected to the drive electrode unit 60B via an amplitude control circuit. When an AC voltage is applied from the self-excited circuit through the amplitude control circuit, an electrostatic attractive force is generated between the movable electrode plate 651a and the fixed electrode plate 652a of the drive electrode unit 60B, and the displacement unit 41 is moved in the x-axis direction. Excited. The drive electrode portion 60A detects the excitation amplitude in the x-axis direction of the displacement portion 41 from the change in electrostatic capacitance of the movable electrode plate 651a and the fixed electrode plate 652a using a capacitance detection circuit. The detection result of the capacitance detection circuit is fed back to the self-excitation circuit, and the self-excitation circuit generates a self-excitation signal based on the detection result. The amplitude control circuit controls the AC voltage so that the excitation amplitude of the displacement unit 41 is constant based on the self-excitation signal. With these configurations, the angular velocity sensor 700 can always excite the displacement portion 41 in the x-axis direction with an appropriate excitation amplitude at an appropriate frequency.

  When an angular velocity in the rotation axis direction (z-axis direction) is applied to the displacement portion 41 while the displacement portion 41 is excited in the excitation direction (x-axis direction), the excitation direction (x-axis direction) and the angular velocity of the displacement portion 41 Coriolis force is generated in the detection direction (y-axis direction) orthogonal to both the rotation axis direction (z-axis direction). The displacement part 41 receives this Coriolis force and vibrates in the detection direction (y-axis direction).

  When the displacement portion 41 vibrates in the detection direction (y-axis direction), the movable electrode portions 51 of the detection electrode portions 50B and 50D also vibrate in the detection direction (y-axis direction). Capacitance detection circuits are connected to the detection electrode portions 50B and 50D. The capacitance detection circuits detect fluctuations in the capacitance of the detection electrode portions 50B and 50D, and supply the detection results to the synchronous detection circuit. The synchronous detection circuit extracts a change that coincides with the cycle of the AC voltage generated by the self-excited circuit from among the fluctuations in capacitance. The period of vibration of the displacement part 41 due to the Coriolis force coincides with the period of excitation of the displacement part 41 by the self-excitation circuit, and the phase advances by π / 2. 41 vibrations are reflected. The synchronous detection circuit further converts the angular velocity from the extracted capacitance fluctuation and supplies it to the angular velocity display unit. The angular velocity display unit displays the input angular velocity. The angular velocity sensor 700 can accurately detect the angular velocity having the rotation axis in the z-axis direction applied to the displacement unit 41 through such a procedure. In the angular velocity sensor 700, since the influence of the warp of the support substrate 21 is reduced, stable excitation and Coriolis force detection are possible, and accurate angular velocity detection is possible.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

21: support substrate 41: displacement part 42: first beam part 43: first fixed part 50: detection electrode part 51: movable electrode part 52: fixed electrode part 53: second beam part 54: second fixed part

Claims (4)

A MEMS structure comprising:
A support substrate, a displacement portion, a movable electrode portion, a fixed electrode portion, a first beam portion, a first fixing portion, a second beam portion, and a second fixing portion;
The displacement portion is supported by the support substrate via the first beam portion and is relatively displaceable with respect to the support substrate along at least a first direction.
The movable electrode portion is connected to the displacement portion and can be relatively displaced with respect to the support substrate along at least the first direction depending on the displacement of the displacement portion,
The fixed electrode portion is supported by the support substrate via the second beam portion, and is configured such that the distance from the movable electrode portion varies depending on the displacement of the movable electrode portion. And
The first beam portion is fixed to the support substrate via the first fixing portion,
The second beam portion is fixed to the support substrate via the second fixing portion,
A MEMS structure in which a distance between the first fixing part and the second fixing part is shorter than a distance between the first fixing part and the fixed electrode part. The fixed electrode portion has a plurality of fixed electrode plates and a fixed electrode plate connecting portion for connecting the plurality of fixed electrode plates,
The MEMS structure according to claim 1, wherein the second beam portion is connected to the fixed electrode plate coupling portion. The movable electrode part and the fixed electrode part are connected via a third beam part,
2. The third beam portion is configured to have a small spring constant in the first direction so that an interval between the movable electrode portion and the fixed electrode portion varies depending on a displacement of the movable electrode portion. Or the MEMS structure of 2. The first direction is a direction perpendicular to the support substrate;
The fixed electrode part is separated from the support substrate by a separation groove that makes a round when observed from the first direction;
2. The MEMS structure according to claim 1, wherein the second beam portion extends beyond the separation groove when observed from the first direction.

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