JP2008054307A - Silicon microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silicon microphone having a high sensitivity and regular performance by reducing distortion of a conductive layer and irregular vibration occurring in the peripheral portion of the conductive layer. <P>SOLUTION: A conductive layer 20 forming a diaphragm 21 is formed with a corrugation 23 between a center portion forming the diaphragm 21 and an outside periphery 22. The corrugation 23 lies across an imaginary line Li connecting a plurality of spacers 43 disposed in a circumferential direction. Since the corrugation 23 is formed across the imaginary line Li, it is possible to increase the rigidity of the conductive layer 20 forming the diaphragm 21. Since the rigidity of the first conductive layer 20 is improved, distortion hardly occurs in the conductive layer 20 due to variation in stress in the center portion and the periphery 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a silicon microphone.

  Conventionally, a silicon microphone that can be manufactured by applying a manufacturing process of a semiconductor device is known. The silicon microphone includes a diaphragm that vibrates by sound waves. Some silicon microphones support a conductive layer portion forming a diaphragm with a plurality of support portions. The support portions are provided at a plurality of locations at equal intervals or unequal intervals in the circumferential direction of the conductive layer portion forming the diaphragm (see Patent Documents 1 and 2).

  However, when the conductive layer portion forming the diaphragm is supported at a plurality of locations in the circumferential direction, the stress inside the conductive layer portion changes in the process of acoustic input. When a change occurs in the stress of the conductive layer portion, the deformation of the diaphragm formed by the conductive layer portion and the conductive layer portion and the stress distribution in the conductive layer portion are biased, and the conductive layer portion is distorted. Therefore, irregular vibration is likely to occur in the peripheral portion located on the outer peripheral side of the central portion as compared with the central portion forming the diaphragm in the conductive layer portion. As a result, there is a problem that in a portion where the vibration is large, contact with the opposite electrode is caused, and in a portion where the vibration is small, the sensitivity is lowered due to a decrease in capacitance change. In addition, since irregular vibration occurs in the peripheral portion as compared with the central portion, there is a problem that it is difficult to predict the performance of the silicon microphone.

JP 2005-535152 gazette US Pat. No. 5,452,268

  SUMMARY OF THE INVENTION An object of the present invention is to provide a silicon microphone that reduces distortion of a conductive layer portion and irregular vibrations in the peripheral portion of the conductive layer portion, has high sensitivity, and achieves uniform performance.

(1) In order to achieve the above object, the silicon microphone of the present invention is provided at a plurality of locations in the circumferential direction of the conductive layer portion and the conductive layer portion forming a diaphragm in the center portion, and supports the conductive layer portion. And a rigid portion that is provided on the conductive layer portion and arranged across a virtual straight line connecting the plurality of support portions.
By disposing the rigid portion across the virtual straight line connecting the plurality of support portions, that is, disposing the rigid portion so as to intersect the virtual straight line, the rigidity of the conductive layer portion forming the diaphragm is improved. When the rigidity of the conductive layer portion is improved, the conductive layer portion is less likely to be distorted due to a change in stress. Therefore, local excessive vibration or excessive vibration of the conductive layer portion is reduced. Therefore, it is possible to reduce irregular vibrations in the peripheral portion located on the outer periphery as compared with the central portion forming the diaphragm, and to increase sensitivity. Further, since the irregular vibration of the conductive layer portion is reduced, the diaphragm vibration is stabilized. Accordingly, the performance and characteristics can be made uniform.

(2) Further, in order to achieve the above object, the silicon microphone of the present invention is provided at a plurality of locations in the circumferential direction of the conductive layer portion, the conductive layer portion forming a diaphragm in the center portion, and the conductive layer portion. And a rigid portion provided on the conductive layer portion and arranged between the plurality of support portions.
The rigidity of the conductive layer part forming the diaphragm is improved by connecting the plurality of support parts and arranging the rigid part, that is, by arranging the rigid part on an imaginary line connecting the plurality of support parts. When the rigidity of the conductive layer portion is improved, the conductive layer portion is less likely to be distorted due to a change in stress. Therefore, local excessive vibration or excessive vibration of the conductive layer portion is reduced. Therefore, it is possible to reduce irregular vibrations in the peripheral portion located on the outer periphery as compared with the central portion forming the diaphragm, and to increase sensitivity. Further, since the irregular vibration of the conductive layer portion is reduced, the diaphragm vibration is stabilized. Accordingly, the performance and characteristics can be made uniform.

(3) Furthermore, in order to achieve the above object, the silicon microphone of the present invention is provided at a plurality of locations in the circumferential direction of the conductive layer portion, and a conductive layer portion that forms a diaphragm in the center, and the conductive layer portion And a rigid portion provided on the conductive layer portion and disposed on the outer peripheral side of the support portion in the conductive layer portion.
By disposing the rigid portion on the outer peripheral side of the plurality of support portions, the rigidity of the conductive layer portion forming the diaphragm is improved. In particular, the conductive layer portion has improved rigidity on the outer peripheral side of the support portion. When the rigidity of the conductive layer portion is improved on the outer peripheral side of the support portion, irregular vibrations in the peripheral portion on the outer peripheral side with respect to the central portion forming the diaphragm are reduced. In addition, the conductive layer portion is less likely to be distorted due to a change in stress due to the improvement in rigidity. Therefore, local excessive vibration or excessive vibration of the conductive layer portion is reduced. Therefore, it is possible to reduce irregular vibrations in the peripheral portion located on the outer periphery as compared with the central portion forming the diaphragm, and to increase sensitivity. Further, since the irregular vibration of the conductive layer portion is reduced, the diaphragm vibration is stabilized. Accordingly, the performance and characteristics can be made uniform.

(4) In the silicon microphone of the present invention, the rigid portion is formed in a circumferential shape concentrically with the conductive layer portion.
Thereby, rigidity improves in the perimeter of the circumferential direction of a conductive layer part. Thereby, the overall rigidity of the conductive layer portion is improved. Therefore, irregular vibrations in the peripheral portion can be reduced, sensitivity can be increased, and performance and characteristics can be made uniform.

(5) In the silicon microphone of the present invention, the rigid portion is formed in an arc shape concentric with the conductive layer portion.
By supporting the conductive layer portion with a plurality of support portions, the rigidity of the conductive layer portion between the support portions becomes smaller than the portion supported by the support portion. Therefore, for example, by arranging the rigid portions in an arc shape between the support portions, the rigidity between the support portions having relatively low rigidity is improved. Thereby, the overall rigidity of the conductive layer portion is improved. Therefore, irregular vibrations in the peripheral portion can be reduced, sensitivity can be increased, and performance and characteristics can be made uniform.

(6) In the silicon microphone of the present invention, the rigid portion is formed radially in the radial direction of the conductive layer portion.
By supporting the conductive layer portion with a plurality of support portions, the rigidity of the conductive layer portion between the support portions becomes smaller than the portion supported by the support portion. Therefore, for example, by arranging the rigid portions radially between the support portions, the rigidity between the support portions having relatively low rigidity is improved. Thereby, the overall rigidity of the conductive layer portion is improved. Therefore, irregular vibrations in the peripheral portion can be reduced, sensitivity can be increased, and performance and characteristics can be made uniform.

(7) In the silicon microphone of the present invention, the rigid portion is a corrugation that forms a step in the thickness direction of the conductive layer portion.
Corrugation forms a step in the plate thickness direction. Therefore, a plurality of corner portions by corrugation are formed in the conductive layer portion. By forming the corner portion by the step in the thickness direction, the rigidity of the conductive layer portion is improved. Therefore, irregular vibrations in the peripheral portion can be reduced, sensitivity can be increased, and performance and characteristics can be made uniform.

(8) In the silicon microphone according to the present invention, the rigid portion is a thick portion where the conductive layer portion is thick.
The rigidity of the conductive layer portion is improved by increasing the thickness of the conductive layer portion. Therefore, irregular vibrations in the peripheral portion can be reduced, sensitivity can be increased, and performance and characteristics can be made uniform.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In each embodiment, substantially the same components are denoted by the same reference numerals.
(First embodiment)
A silicon microphone according to a first embodiment of the present invention is shown in FIG. The silicon microphone 10 shown in FIG. 1 is manufactured by applying a semiconductor manufacturing process.

  The silicon microphone 10 includes a silicon substrate 11, a first conductive layer part 20, a second conductive layer part 30, and an insulating layer part 40. The silicon substrate 11 is made of, for example, single crystal silicon. The silicon substrate 11 has a cavity 12 as an opening. The cavity 12 penetrates the silicon substrate 11 in the thickness direction.

The insulating layer portion 40 is stacked on the end surface 13 side of the silicon substrate 11. The insulating layer portion 40 is an oxide layer formed of, for example, silicon dioxide. The insulating layer portion 40 has an opening 41 on the inner peripheral side. A support portion 42 that supports the second conductive layer portion 30 is formed on the outer peripheral side of the opening 41 in the insulating layer portion 40.
The second conductive layer portion 30 is stacked on the opposite side of the insulating layer portion 40 from the silicon substrate 11. The second conductive layer portion 30 is a conductive layer formed of, for example, polysilicon doped with phosphorus as an impurity. The outer peripheral side of the second conductive layer part 30 is supported by a support part 42 formed by the insulating layer part 40. The second conductive layer portion 30 forms a beam 31 at a portion protruding from the support portion 42 toward the inner peripheral side. A plurality of beams 31 are provided in the circumferential direction of the second conductive layer portion 30. A spacer 43 is connected to the beam 31. The spacer 43 supports the first conductive layer portion 20 at the end opposite to the beam 31. The spacer 43 extending from the beam 31 constitutes a support portion that supports the first conductive layer portion 20. That is, the spacer 43 is a support part in claims. Accordingly, the spacer 43 supports the first conductive layer portion 20 at a plurality of positions in the circumferential direction of the first conductive layer portion 20.

  The first conductive layer portion 20 is supported by spacers 43 extending from the beam 31 at a plurality of locations in the circumferential direction. Accordingly, the first conductive layer portion 20 is suspended from the beam 31 formed by the second conductive layer portion 30 by the spacer 43. The first conductive layer portion 20 is a conductive layer formed of polysilicon doped with an impurity such as phosphorus, for example, like the second conductive layer portion 30. The first conductive layer portion 20 has a central portion that forms the diaphragm 21 on the inner peripheral side of the portion supported by the spacer 43. The diaphragm 21 is vibrated by sound waves. A peripheral portion 22 is formed on the outer peripheral side of the diaphragm 21 of the first conductive layer portion 20.

  In the second conductive layer portion 30, the inner peripheral side of the beam 31 forms a plate 33 as a back plate facing the diaphragm 21. The plate 33 has a plurality of through holes 34. The through hole 34 penetrates the second conductive layer portion 30 forming the plate 33 in the plate thickness direction. The second conductive layer portion 30 and the silicon substrate 11 are electrically insulated by an insulating layer portion 40 that is an insulator. In addition, the spacer 43 that supports the first conductive layer portion 20 on the second conductive layer portion 30 is formed of an insulator in the same manner as the insulating layer portion 40. Thereby, the first conductive layer portion 20 and the second conductive layer portion 30 are insulated by the spacer 43. In FIG. 1A, the description of the plate 33 formed by the second conductive layer portion 30 is omitted.

  The diaphragm 21 and the silicon substrate 11 are connected to a bias power source 50 as shown in FIG. Both the silicon substrate 11 and the first conductive layer portion 20 are conductive. Therefore, the diaphragm 21 and the silicon substrate 11 have substantially the same potential. On the other hand, the plate 33 is connected to the input terminal of the operational amplifier 51. The operational amplifier 51 is set to have a high input impedance.

  When the sound wave propagates to the diaphragm 21 via the through hole 34 of the plate 33, the diaphragm 21 is vibrated by the sound wave. The distance between the diaphragm 21 and the plate 33 is changed by the vibration of the diaphragm 21. A space sandwiched between the diaphragm 21 and the plate 33 is filled with air as an insulator. Therefore, when the distance between the diaphragm 21 and the plate 33 changes, the capacitance between the diaphragm 21 and the plate 33 changes.

  The plate 33 is connected to the operational amplifier 51 having a high input impedance. For this reason, even if the electrostatic capacitances of the diaphragm 21 and the plate 33 change, the amount of charge existing on the plate 33 moves to the operational amplifier 51 is small. As a result, it can be considered that there is almost no change in charge existing in the diaphragm 21 and the plate 33. As a result, a change in capacitance between the diaphragm 21 and the plate 33 is detected as a change in the potential of the plate 33. Therefore, the silicon microphone 10 outputs a slight change in the potential of the plate 33 accompanying the change in capacitance as an electrical signal. That is, the silicon microphone 10 converts a change in sound pressure applied to the diaphragm 21 into a change in capacitance, and converts the converted change in capacitance into a change in voltage, thereby correlating an electric signal correlated with the sound pressure. Is output.

The silicon microphone 10 includes a corrugation 23 as a rigid portion in the first conductive layer portion 20. The corrugation 23 is provided between the central portion of the first conductive layer portion 20 that forms the diaphragm 21 and the peripheral portion 22 on the outer peripheral side thereof. The corrugation 23 is formed in a groove shape between the central portion and the peripheral portion 22 that form the diaphragm 21 of the first conductive layer portion 20. The corrugation 23 is formed to be recessed from the first conductive layer portion 20 to the side opposite to the second conductive layer portion 30. In the case of the first embodiment, the corrugation 23 is formed continuously in the circumferential direction on a concentric circle with the first conductive layer portion 20 that forms the diaphragm 21. In the first embodiment, the corrugation 23 across the imaginary straight line L _i connecting a plurality of spacers 43. The virtual straight line _Li is a virtual straight line obtained by linearly connecting a plurality of spacers 43 provided in the circumferential direction of the silicon microphone 10.

By forming the corrugation 23, a step is formed in the first conductive layer portion 20 in the thickness direction. Due to this step, a corner 24 is formed in the first conductive layer portion 20. That is, the first conductive layer portion 20 is formed with a plurality of corner portions 24 from the center side to the peripheral side. By forming the plurality of corner portions 24 by the corrugation 23 of the first conductive layer portion 20, the rigidity of the first conductive layer portion 20 in the circumferential direction and the radial direction is improved in the portion where the corrugation 23 is provided. By arranging the corrugations 23 across the virtual line L _i, the central portion forming a diaphragm 21, rigidity of the first conductive layer portion 20 made of the peripheral portion 22. The overall improvement. That is, the overall rigidity of the first conductive layer portion 20 is improved by forming the corrugation 23. When the rigidity of the first conductive layer portion 20 is improved, the first conductive layer portion 20 is less likely to be distorted due to a change in stress. For this reason, the first conductive layer portion 20 is reduced from occurrence of local excessive vibration or excessive vibration. As a result, in the first conductive layer portion 20, irregular vibrations generated in the peripheral portion 22 located on the outer peripheral side of the central portion forming the diaphragm 21 are reduced. Therefore, the vibration of the first conductive layer portion 20 is stabilized, the contact between the first conductive layer portion 20 and the second conductive layer portion 30 due to the irregular and excessive vibration of the peripheral portion 22, and the central portion forming the diaphragm 21. It is possible to reduce a decrease in sensitivity due to an excessive vibration of.

  Further, by reducing irregular and excessive vibration of the peripheral portion 22, contact between the first conductive layer portion 20 and the second conductive layer portion 30 due to vibration is reduced. Therefore, the distance set between the first conductive layer part 20 and the second conductive layer part 30 can be reduced. As a result, the distance between the diaphragm 21 and the plate 33 can be reduced, and the sensitivity of the silicon microphone 10 can be increased. Furthermore, since the vibration of the first conductive layer portion 20 is stabilized, the performance and characteristics of the silicon microphone 10 can be made uniform.

Next, a method for manufacturing the silicon microphone 10 according to the first embodiment will be described with reference to FIGS.
As shown in FIG. 2 (A1), an oxide layer 62 is formed on one end surface 61 of the silicon substrate 60. The oxide layer 62 is formed by growing silicon dioxide on one end face 61 of the silicon substrate 60. The formed oxide layer 62 becomes the insulating layer portion 40 shown in FIG. In the formed oxide layer 62, a recess 63 is formed in part as shown in FIG. The recess 63 is formed by, for example, forming a mask with a resist and then etching the oxide layer 62 with hydrogen fluoride. The thickness of the oxide layer 62 corresponds to the depth of the corrugation 23 of the first conductive layer portion 20 shown in FIG. The oxide layer 62 is etched until the end surface 61 of the silicon substrate 60 is exposed from the recess 63.

  When the recess 63 is formed by etching the oxide layer 62, the first conductive layer portion 64 is formed on the oxide layer 62 and the end surface 61 of the silicon substrate 60 exposed from the oxide layer 62 as shown in FIG. Laminated. The first conductive layer portion 64 is formed by depositing polysilicon. The outer peripheral side of the formed first conductive layer portion 64 is removed by patterning as shown in FIG. 2 (A4).

  When the patterning of the first conductive layer portion 64 is completed, an oxide layer 62 is further formed as shown in FIG. 2 (A5). A second conductive layer portion 66 is further laminated on the end surface 65 of the oxide layer 62 opposite to the silicon substrate 60. The oxide layer 62 is formed on the opposite side of the first conductive layer portion 64 from the silicon substrate 60. As a result, the first conductive layer portion 64 is buried inside the oxide layer 62. After the oxide layer 62 is sufficiently grown, the second conductive layer portion 66 is laminated on the opposite end surface of the silicon substrate 60. The second conductive layer portion 66 is formed by depositing polysilicon similarly to the first conductive layer portion 64.

When the formation of the oxide layer 62 and the second conductive layer portion 66 is completed, the second conductive layer portion 66 is patterned as shown in FIG. By patterning the second conductive layer portion 66, a recess 67 corresponding to the through hole 34 of the second conductive layer portion 30 is formed.
When the patterning of the second conductive layer portion 66 is completed, the silicon substrate 60 is patterned as shown in FIG. Patterning of the silicon substrate 60 is performed using an anisotropic or isotropic etching solution after a mask 69 is formed on the end surface 68 of the silicon substrate 60 with a resist. Thereby, an opening 71 to be the cavity 12 is formed in the silicon substrate 60.

  Further, a mask 72 that covers the oxide layer 62 exposed from the second conductive layer portion 66 is formed on the second conductive layer portion 66 side as shown in FIG. 3 (A7). Then, the oxide layer 62 is etched by hydrogen fluoride through the recess 67 and the opening 71. The oxide layer 62 is covered with a mask 72 on the outer peripheral side of the second conductive layer portion 66. Therefore, on the outer peripheral side of the first conductive layer portion 64, the oxide layer 62 remains without etching the portion corresponding to the support portion 42. Further, as shown in FIG. 4, by appropriately setting the width of the remaining portion 73 of the second conductive layer portion 66 remaining between the through holes 34 formed by the recessed portion 67, the remaining portion 73 is made closer to the silicon substrate 60 side. The spacer 74 formed by the oxide layer 62 remains without being etched. Thereby, the first conductive layer portion 64 is supported by the spacer 74 made of the oxide layer 62 remaining between the second conductive layer portion 66.

By etching the oxide layer 62, the oxide layer 62 is removed except for the portions to be the support portions 42 and the spacers 43 as shown in FIG. 3 (A8) and FIG. Further, the first conductive layer portion 64 is formed with a recess 75 that becomes the corrugation 23. After the oxide layer 62 is etched, the mask 72 is removed as shown in FIG.
After the above steps, the silicon microphone 10 is completed through steps such as dicing and packaging.

In the silicon microphone 10 according to the first embodiment, the first conductive layer portion 20 that forms the diaphragm 21 includes a corrugation 23 between the central portion that forms the diaphragm 21 and the peripheral portion 22 outside thereof. Corrugation 23 is arranged across the virtual line L _i connecting the spacer 43 which is more disposed circumferentially. By arranging the corrugations 23 across the virtual line L _i, the rigidity of the first conductive layer 20 forming the diaphragm 21 is improved overall. As the rigidity of the first conductive layer portion 20 is improved, the first conductive layer portion 20 is less likely to be distorted due to a change in stress. Therefore, in the first conductive layer portion 20, local excessive vibration or excessive vibration is reduced, and irregular vibration generated in the peripheral portion 22 located on the outer peripheral side of the central portion forming the diaphragm 21 is reduced. The Therefore, the vibration of the first conductive layer portion 20 is stabilized, the sensitivity can be increased, and the performance and characteristics of the silicon microphone 10 can be made uniform.

(Second and third embodiments)
A silicon microphone according to the second and third embodiments of the present invention is shown in FIG. 5 or FIG.
In the second embodiment, as shown in FIG. 5, the corrugation 23 of the first conductive layer portion 20 protrudes toward the second conductive layer portion 30. The rigidity of the first conductive layer portion 20 is improved by providing the corrugation 23 regardless of the protruding direction. Therefore, the corrugation 23 may be formed so as to protrude toward the second conductive layer portion 30 as in the second embodiment.

  In 3rd Embodiment, as shown in FIG. 6, the 1st conductive layer part 20 has the thick part 25 as a rigid part. The thick part 25 is formed by increasing the thickness of a part of the first conductive layer part 20. The thick part 25 improves the rigidity of the first conductive layer part 20 similarly to the corrugation 23 of the first embodiment. That is, in order to increase the rigidity of the first conductive layer portion 20, not only the corrugation 23 but also the thick portion 25 may be formed.

(Modification of corrugation arrangement)
In the first embodiment described above has described an example of placing corrugations 23 across the imaginary straight line L _i connecting the spacer 43 as shown in FIG. Moreover, the corrugation 23 demonstrated the example formed continuously in the circumferential direction of the 1st conductive layer part 20. As shown in FIG. However, the corrugation 23 may be disposed at a position that satisfies any of the following conditions.

(1) connecting a plurality of spacers 43 to form across a virtual line L _i (First Embodiment)
(2) Arranged between the plurality of spacers 43 (3) Arranged on the outer peripheral side of the plurality of spacers 43 An example that satisfies the above conditions will be specifically described below.

(Fourth and fifth embodiments)
A fourth embodiment of the present invention is shown in FIG.
The silicon microphone 10 according to the fourth embodiment shown in FIG. 7 satisfies the above condition (2). That is, in the fourth embodiment, the corrugation 23 is disposed between the spacers 43 that are installed in the circumferential direction of the first conductive layer portion 20. In the case of the fourth embodiment, the corrugation 23 connects a plurality of spacers 43 linearly.

A fifth embodiment of the present invention is shown in FIG.
The silicon microphone 10 according to the fifth embodiment shown in FIG. 8 satisfies the above condition (2). That is, in the fifth embodiment, the corrugation 23 is disposed between the spacers 43 that are installed in the circumferential direction of the first conductive layer portion 20. In the case of the fifth embodiment, the corrugation 23 has a plurality of spacers 43 concentrically connected with the first conductive layer portion 20 in an arc shape.

  As in the fourth embodiment or the fifth embodiment, by forming the corrugation 23 that connects the plurality of spacers 43 to the first conductive layer portion 20, the rigidity of the first conductive layer portion 20 that forms the diaphragm 21 is as a whole. To improve. As the rigidity of the first conductive layer portion 20 is improved, the first conductive layer portion 20 is less likely to be distorted due to a change in stress. Therefore, the first conductive layer portion 20 is reduced in the occurrence of local excessive vibration or excessive vibration, and irregular vibration generated in the peripheral portion 22 located on the outer peripheral side of the central portion forming the diaphragm 21 is reduced. Reduced. Therefore, the vibration of the first conductive layer portion 20 is stabilized, the sensitivity can be increased, and the performance and characteristics of the silicon microphone 10 can be made uniform.

In addition, if the corrugation 23 in 4th Embodiment and 5th Embodiment is demonstrated still in detail, the corrugation 23 which connects between the some spacers 43 should just be arrange | positioned on the virtual line which connects the spacer 43. FIG. . For example, as shown in FIGS. 9 and 10, the corrugation 23 may be disposed on the virtual line L _ii connecting the spacers 43. In the example shown in FIG. 9, a straight line connecting adjacent spacers 43 is a virtual line L _ii , and in the example shown in FIG. 10, an arcuate curve connecting adjacent spacers 43 is a virtual line L _ii . By arranging the corrugation 23 along the virtual line L _ii , it is difficult for the first conductive layer portion 20 to be distorted due to the change in stress.

(Sixth embodiment)
A silicon microphone according to a sixth embodiment of the present invention is shown in FIG.
The silicon microphone 10 shown in FIG. 11 satisfies the above condition (1). That is, in the sixth embodiment, the corrugation 23 is arranged across the virtual line L _i connecting the spacer 43 which is more disposed in the circumferential direction of the first conductive layer 20. The sixth embodiment, the corrugation 23 is formed radially across the virtual line L _i between the plurality of spacers 43.

As in the sixth embodiment, by forming the corrugations 23 which cross the imaginary straight line L _i to the first conductive layer portion 20, the rigidity of the first conductive layer 20 forming the diaphragm 21 is improved overall. Accordingly, as in the first embodiment, the vibration of the first conductive layer portion 20 is stabilized, the sensitivity can be increased, and the performance and characteristics of the silicon microphone 10 can be made uniform.
In the silicon microphone 10 according to the sixth embodiment, an example is shown in which three corrugations 23 are arranged radially between the spacers 43. However, the number or angle of the corrugations 23 can be arbitrarily determined according to the characteristics of the silicon microphone 10.

(Seventh embodiment)
A silicon microphone according to a seventh embodiment of the present invention is shown in FIG.
The silicon microphone shown in FIG. 12 satisfies the above condition (3). That is, in the seventh embodiment, the corrugation 23 is disposed on the outer peripheral side of each spacer 43 that is installed in the circumferential direction of the first conductive layer portion 20. In the case of the seventh embodiment, the corrugation 23 is provided concentrically with the first conductive layer portion 20 on the outer peripheral side of the plurality of spacers 43. Accordingly, the corrugation 23 is continuously formed on the circumference on the outer peripheral side of the spacer 43.

  By forming the corrugation 23 on the outer peripheral side of the spacer 43 of the first conductive layer portion 20 as in the seventh embodiment, the rigidity of the first conductive layer portion 20 forming the diaphragm 21 is improved as a whole. As the rigidity of the first conductive layer portion 20 is improved, the first conductive layer portion 20 is less likely to be distorted due to a change in stress. Therefore, the first conductive layer portion 20 is reduced in the occurrence of local excessive vibration or excessive vibration, and irregular vibration generated in the peripheral portion 22 located on the outer peripheral side of the central portion forming the diaphragm 21 is reduced. Reduced. Therefore, the vibration of the first conductive layer portion 20 is stabilized, the sensitivity can be increased, and the performance and characteristics of the silicon microphone 10 can be made uniform.

(Other embodiments)
In the plurality of embodiments described above, the example in which the first conductive layer portion 20 forming the diaphragm 21 is supported by the spacer 43 extending from the second conductive layer portion 30 has been described. However, the present invention is not limited to the example in which the first conductive layer portion 20 is supported by the spacer 43, and can be applied.

As shown in FIG. 13, the first conductive layer portion 20 forming the diaphragm 21 may be configured to be supported by the silicon substrate 11. In this case, the silicon substrate 11 that forms the cavity 12 forms a support portion that supports the first conductive layer portion 20.
As shown in FIG. 14, the first conductive layer portion 20 forming the diaphragm 21 may be supported by a support portion 14 extending from the silicon substrate 11.

  Further, as shown in FIG. 15, the first conductive layer portion 20 forming the diaphragm 21 may be moved to the second conductive layer portion 30 side. In the case of the silicon microphone 10 shown in FIG. 15, when the first conductive layer portion 20 and the second conductive layer portion 30 are energized, the electrostatic attraction between the first conductive layer portion 20 and the second conductive layer portion 30 causes the first The one conductive layer part 20 is attracted to the second conductive layer part 30 side. The movement of the first conductive layer portion 20 is restricted by contacting the spacer 44 extending from the second conductive layer portion 30. Thus, the first conductive layer portion 20 forming the diaphragm 21 moves to the second conductive layer portion 30 side when energized. At this time, the spacer 44 constitutes a support portion that supports the first conductive layer portion 20.

In the plurality of embodiments described above, the example in which the spacers 43 serving as the support portions are arranged at four locations in the circumferential direction of the first conductive layer portion 20 and the second conductive layer portion 30 has been described. However, the spacers 43 serving as the support portions can be arranged not limited to four places as long as there are two or more places. When there are two spacers 43, the rigid portion may be arranged on an arcuate imaginary line connecting the spacers.
Moreover, in several embodiment, the 1st conductive layer part 20 which forms the diaphragm 21, the 2nd conductive layer part 30 which forms the plate 33, etc. were demonstrated in the circular shape. However, the first conductive layer portion 20 and the second conductive layer portion 30 are not limited to a circular shape, and may be formed in an elliptical shape, a rectangular shape, or a polygonal shape.
Furthermore, in the above-described plurality of embodiments, the condenser microphone 10 to which each embodiment is individually applied has been described. However, a plurality of embodiments may be combined and applied to the capacitor microphone 10.

It is a figure which shows the outline of the silicon microphone by 1st Embodiment of this invention, Comprising: (A) is the top view which looked at the 1st conductive layer part from the 2nd conductive layer part side, (B) is B of (A). Sectional drawing in the -B line, (C) is sectional drawing in the CC line of (A). Sectional drawing which shows the manufacturing process of the silicon microphone by 1st Embodiment of this invention. Sectional drawing which shows the manufacturing process of the silicon microphone by 1st Embodiment of this invention. It is sectional drawing which shows the manufacturing process of the silicon microphone by 1st Embodiment of this invention, Comprising: The figure which expanded the vicinity of the spacer. Sectional drawing which shows the outline of the silicon microphone by 2nd Embodiment of this invention. Sectional drawing which shows the outline of the silicon microphone by 3rd Embodiment of this invention. It is a figure which shows the outline of the silicon microphone by 4th Embodiment of this invention, Comprising: The top view which looked at the 1st conductive layer part from the 2nd conductive layer part side. It is a figure which shows the outline of the silicon microphone by 5th Embodiment of this invention, Comprising: The top view which looked at the 1st conductive layer part from the 2nd conductive layer part side. It is a figure which shows the outline of the silicon microphone by 4th Embodiment of this invention, Comprising: The top view which looked at the 1st conductive layer part from the 2nd conductive layer part side. It is a figure which shows the outline of the silicon microphone by 5th Embodiment of this invention, Comprising: The top view which looked at the 1st conductive layer part from the 2nd conductive layer part side. It is a figure which shows the outline of the silicon microphone by 6th Embodiment of this invention, Comprising: The top view which looked at the 1st conductive layer part from the 2nd conductive layer part side. It is a figure which shows the outline of the silicon microphone by 7th Embodiment of this invention, Comprising: The top view which looked at the 1st conductive layer part from the 2nd conductive layer part side. Sectional drawing which shows the outline of the silicon microphone by other embodiment of this invention. Sectional drawing which shows the outline of the silicon microphone by other embodiment of this invention. Sectional drawing which shows the outline of the silicon microphone by other embodiment of this invention.

Explanation of symbols

10: Silicon microphone, 11: Silicon substrate, 20: First conductive layer part, 21: Diaphragm, 23: Corrugation (rigid part), 25: Thick part, 30: Second conductive layer part, 33: Plate, 40: Insulating layer part 43: Spacer (supporting part)

Claims (8)

A conductive layer that forms a diaphragm in the center; and
Provided in a plurality of locations in the circumferential direction of the conductive layer portion, and a support portion for supporting the conductive layer portion;
A rigid portion provided in the conductive layer portion and disposed across an imaginary straight line connecting the plurality of support portions;
Silicon microphone equipped with. A conductive layer that forms a diaphragm in the center; and
Provided in a plurality of locations in the circumferential direction of the conductive layer portion, and a support portion for supporting the conductive layer portion;
A rigid portion provided on the conductive layer portion and disposed between the plurality of support portions;
Silicon microphone equipped with. A conductive layer that forms a diaphragm in the center; and
Provided in a plurality of locations in the circumferential direction of the conductive layer portion, and a support portion for supporting the conductive layer portion;
A rigid portion that is provided on the conductive layer portion and disposed on the outer peripheral side of the support portion in the conductive layer portion;
Silicon microphone equipped with.   4. The silicon microphone according to claim 1, wherein the rigid portion is formed in a circumferential shape concentrically with the conductive layer portion.   The silicon microphone according to claim 1, wherein the rigid portion is formed in an arc shape concentrically with the conductive layer portion.   The silicon microphone according to claim 1, wherein the rigid portion is formed radially in a radial direction of the conductive layer portion.   The silicon microphone according to claim 1, wherein the rigid portion is a corrugation that forms a step in a plate thickness direction of the conductive layer portion.   The silicon microphone according to claim 1, wherein the rigid portion is a thick portion where a thickness of the conductive layer portion is large.