JP2008244752A - Electrostatic pressure transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To combine stability with sensitivity of an electrostatic pressure transducer at a high level in a balanced manner. <P>SOLUTION: The electrostatic pressure transducer includes: a substrate; an electrode plate comprising a deposition film on the substrate; a diaphragm comprising a deposition film having a gap between the electrode plate and forming a counter electrode facing the electrode plate with the gap therebetween; and a cantilever comprising a deposition layer deposited on a layer closer to the electrode plate than the diaphragm, pushing the diaphragm in a state where the cantilever is bent in the direction of approaching the diaphragm from a proximal end part to a distal end part by internal stress. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrostatic pressure transducer and a method for manufacturing the same, and more particularly to an electrostatic pressure transducer suitable as a microphone.

Conventionally, for example, a so-called silicon microphone is known as a minute electrostatic pressure transducer manufactured by applying a semiconductor manufacturing process. In the electrostatic pressure transducer described in Patent Document 1, a pair of counter electrodes is formed by an electrode plate having a relatively high rigidity and a diaphragm having a relatively low rigidity. Further, the gap between the electrode plate and the diaphragm is narrowed when the diaphragm is attracted to the electrode plate by an electric field due to a bias voltage, and is maintained by the diaphragm coming into contact with the convex portion formed on the electrode plate.
JP-T-2004-506394

  However, the electrostatic pressure transducer described in Patent Document 1 has the following problems. That is, although the sensitivity increases as the distance between the electrode plate and the diaphragm is narrow, the pull-in phenomenon that the diaphragm deflected by pressurization is attracted to the electrode plate by the bias voltage is likely to occur. There is a problem of being lowered. Further, when the diaphragm is attracted to the electrode plate, the distance between the diaphragm and the substrate is widened, so that there is a problem that the acoustic resistance of the space leading to the back cavity formed in the substrate is reduced and the sensitivity in the low range is lowered.

  The present invention has been created in view of these problems, and an object of the present invention is to balance the stability and sensitivity of an electrostatic pressure transducer at a high level with a good balance.

(1) An electrostatic pressure transducer for achieving the above object comprises a substrate, an electrode plate comprising a deposited film on the substrate, and a deposited film having a gap between the electrode plate and the gap. A diaphragm forming a counter electrode facing the electrode plate, and a deposited film deposited in a layer closer to the electrode plate than the diaphragm, and the diaphragm from the base end portion toward the tip end portion due to internal stress And a cantilever beam that pushes in the diaphragm in a state of being bent in a direction approaching.
According to this electrostatic pressure transducer, the distance between the electrode plate and the diaphragm is expanded by the internal stress of the cantilever rather than the state of the manufacturing process in which the film constituting the electrode plate and the diaphragm is deposited. For this reason, this electrostatic pressure transducer is more stable than the electrostatic pressure transducer in which the distance between the electrode plate and the diaphragm is maintained in the state of the manufacturing process in which the film constituting the electrode plate and the diaphragm is deposited. Increases nature.

(2) In the electrostatic pressure transducer for achieving the above object, the substrate forms an opening of a back cavity, and the deposited film forming the electrode plate has a first vent hole, And the 2nd gap | interval which functions as an acoustic resistance between the said back cavity and the said 1st ventilation hole exists between the edge part of the said diaphragm, and the edge part of the said board | substrate, and forms the said diaphragm. A second vent hole that communicates the first vent hole and the second gap is formed outside the opening of the back cavity of the deposited film, and between the electrode plate and the diaphragm. The certain gap may communicate with the first vent hole.
According to this electrostatic pressure transducer, the pressure vibration that displaces the diaphragm is transmitted to the diaphragm through the first vent hole in the electrode plate. If the space capacity on the side opposite to the electrode plate of the diaphragm is narrow and sealed, the pressure in the space acts as a reaction force, so that the displacement of the diaphragm becomes small, resulting in a decrease in sensitivity. Moreover, the diaphragm is destroyed by the difference between the pressure in the space and the atmospheric pressure. In the present invention, these problems are solved. According to the present invention, the second gap that functions as an acoustic resistance between the diaphragm and the substrate is made narrower than the thickness of the sacrificial film that must be deposited between the deposited film constituting the diaphragm and the substrate. Can do. Therefore, in the case of the present invention, it is possible to increase the low-frequency sensitivity and at the same time improve the stability, and balance the low-frequency sensitivity and stability at a high level.

(3) In the electrostatic pressure transducer for achieving the above object, the diaphragm may have a convex portion whose tip is in contact with the substrate and forms the second gap. .
In this case, since the width of the gap between the diaphragm and the substrate is determined by the convex portion of the diaphragm, sensitivity and stability can be set with high accuracy.

(4) In the electrostatic pressure transducer for achieving the above object, the back surface of the convex portion made of a deposited film whose surface is in contact with the diaphragm and forms the second gap is formed on the substrate. May be joined.
In this case, the width of the gap between the diaphragm and the substrate is determined by the convex portion made of the deposited film bonded to the substrate, so that sensitivity and stability can be set with high accuracy.

(5) In the electrostatic pressure transducer for achieving the above object, the substrate may have a groove forming the second gap formed outward from the opening of the back cavity. .
In this case, since the width of the gap between the diaphragm and the substrate is determined by the groove formed in the substrate, the sensitivity and stability can be set with high accuracy.

(6) In the electrostatic pressure transducer for achieving the above object, a plurality of the second vent holes are formed, and the deposited film forming the diaphragm is bent between the adjacent second vent holes. It may have a strip-shaped contour.
In this case, since the diaphragm is easily displaced, it is possible to reduce the internal stress of the cantilever beam that needs to be generated at the time of manufacturing in order to widen the gap between the diaphragm and the plate and increase the sensitivity of the low range.

(7) In the electrostatic pressure transducer for achieving the above object, the cantilever may be composed of a multi-layered deposited film.
In this case, it becomes easy to create a change in internal stress in the film thickness direction.

(8) In the electrostatic pressure transducer for achieving the above object, at least a part of the cantilever beam and the electrode plate may be formed of a common deposited film.
In this case, the manufacturing cost can be reduced.

(9) In the electrostatic pressure transducer for achieving the above object, the cantilever has a protrusion at the tip that protrudes toward the diaphragm and has a tip that contacts the diaphragm. You may do it.
In this case, the internal stress that needs to be created in the manufacturing process to bring the cantilever into contact with the diaphragm is reduced.

(10) In the electrostatic pressure transducer for achieving the above object, the diaphragm has a convex portion that protrudes toward the cantilever and contacts the tip portion of the cantilever. You may do it.
In this case, the internal stress that needs to be created in the manufacturing process to bring the cantilever into contact with the diaphragm is reduced.

(11) The electrostatic pressure transducer for achieving the above object may be a microphone.
Such a microphone has a high sensitivity in the low range, and has an excellent balance between sensitivity and stability.
In the claims, “to the top” means both “without an intermediate on the top” and “with an intermediate on the top” unless there is a technical impediment. To do.

Hereinafter, embodiments of the present invention will be described in the following order with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.
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1. Structure 2. 2. Manufacturing method Function and effect 4. Other Embodiments ***********

1. Structure FIGS. 1A and 1B are schematic cross-sectional views showing a main part of a condenser microphone as an embodiment of an electrostatic pressure transducer according to the present invention. The condenser microphone 1 is a chip in which a plurality of thin films are deposited on a substrate 16 made of silicon or the like, and is packaged by a wiring substrate and a cover (not shown).

A through hole H4 is formed in the substrate 16. The opening 161 of the through hole H4 forms an opening of the back cavity BC that is closed by a wiring board (not shown).
The first spacer film 15 is made of an insulating film such as SiO ₂ deposited on the surface of the substrate 16. A substantially circular through hole H3 is formed in the first spacer film 15.
The diaphragm electrode film 14 is made of a conductive film such as polycrystalline Si doped with an impurity such as P deposited on the surface of the first spacer film 15.
The second spacer film 13 is made of an insulating film such as SiO ₂ deposited on the surface of the diaphragm electrode film 14. A substantially circular through hole H2 is formed in the second spacer film 13.
The plate electrode film 12 is made of a conductive film such as polycrystalline Si doped with an impurity such as P deposited on the surface of the second spacer film 13. The plate electrode film 12 retains internal stress in the tensile direction.
In the compression film 11, internal stress in the compression direction remains in the compression film 11 made of an insulating film such as SiO ₂ deposited on the surface of the plate electrode film 12.

FIG. 1C is a plan view showing a main part of the condenser microphone 1.
The electrode plate 110 is made of a plate electrode film 12. The plate electrode film 12 has an outer edge bonded to the second spacer film 13 and is stretched over the second spacer film 13 so as to close the through hole H2. The electrode plate 110 is formed with a plurality of through holes H1 as first vent holes. The outline of the electrode plate 110 is determined by the outline of the through hole H2, but is not particularly limited as long as the area facing the diaphragm 120 is large and sufficient bending rigidity can be obtained. The electrode plate 110 is connected to a pad 112 for wiring.

  The first gap G1 between the electrode plate 110 and the diaphragm 120 appears when the through hole H2 is formed in the second spacer film 13, expands when the cantilever 100 is bent, and the diaphragm 120 It is constant by contacting the substrate 16. The first gap G1 communicates with the atmospheric pressure space through the through hole H1 and the slit S.

  As shown in FIG. 1A, the cantilever 100 includes a plate electrode film 12 and a compression film 11, and is separated from the electrode plate 110 by a slit S formed in the plate electrode film 12. The cantilever 100 has a proximal end joined to the second spacer film 13 and protrudes toward the center of the through hole H <b> 2 of the second spacer film 13. Since the internal stress in the tensile direction remains on the plate electrode film 12 near the diaphragm electrode film 14 and the internal stress in the compression direction remains on the compression film 11 far from the diaphragm electrode film 14, the cantilever 100 is fixed at the fixed end. The diaphragm 120 is pushed toward the substrate 16 in a state of being bent in a direction approaching the diaphragm 120 from a certain base end portion toward a distal end portion which is a free end.

  A protruding portion 101 that protrudes toward the diaphragm 120 and is in contact with the diaphragm 120 is formed at the tip of the cantilever 100. The height of the convex portion 101 is lower than the thickness of the second spacer film 13 that separates the diaphragm electrode film 14 and the plate electrode film 12. However, since the cantilever 100 is bent due to internal stress, the tip of the convex portion 101 pushes the diaphragm 120 toward the substrate 16 in a state where the tip is in contact with the diaphragm 120. The convex portion 101 may be formed of the diaphragm electrode film 14 or may be formed of another deposited film bonded to the diaphragm electrode film 14. Further, the convex portion 101 may be insulative or conductive.

  In order to bend the cantilever beam 100 in the direction approaching the diaphragm 120, the internal stress of the cantilever beam 100 is reduced so that the internal stress of the cantilever beam 100 decreases when approaching the diaphragm 120 when the compression direction is positive. It is desirable that the stress be different in the film thickness direction. In the case of the two-layer structure as in the present embodiment, in order to make the internal stress different in the film thickness direction in this way, the internal stress in the compression direction is left in the film far from the diaphragm 120 and the one closer to the diaphragm 120 is left. It is desirable to leave an internal stress in the tensile direction on the membrane. Even in the case of a single layer structure, it is possible to control so that the internal stress (with the compression direction being positive) increases toward the surface side by changing the film formation conditions during the film deposition. Even if the film formation conditions are not changed during film deposition, the internal stress (with the compression direction being positive) may increase toward the surface side. For example, when polycrystal Si is deposited while doping P in-situ, the doping amount is increased, P is ion-implanted from the surface side after polycrystal Si deposition, or after polycrystal Si deposition. When lamp annealing is performed from the surface side, the internal stress (with the compression direction being positive) increases toward the surface side of the polycrystalline Si film. It is also possible to bend the cantilever beam 100 in the direction approaching the diaphragm 120 only by the internal stress in the tensile direction. In this case, the deposited film constituting the cantilever 100 may be formed so that the internal stress in the tensile direction increases as the diaphragm 120 approaches.

  FIG. 2B is a plan view showing a pattern of the diaphragm electrode film 14. The diaphragm electrode film 14 forms a diaphragm 120, a connection part 121 for stretching the diaphragm 120 to the first spacer film 15, a guard electrode 130, and pads 131 and 124. The diaphragm electrode film 14 is made of, for example, a conductive film such as polycrystalline Si doped with P as an impurity. The contour of the diaphragm 120 includes an opening 161 of the back cavity BC formed in the substrate 16. That is, the opening 161 of the back cavity BC is covered with the diaphragm 120.

  The diaphragm 120 and the guard electrode 130 are separated from each other, and a part of the gap separating the diaphragm 120 and the guard electrode 130 forms a vent hole 122 (second vent hole). In FIG. 2B, a portion corresponding to the vent hole 122 is indicated by hatching. Since the ventilation hole 122 is formed outside the opening 161 of the back cavity BC, a second gap G2 is formed between the edge of the diaphragm 120 and the edge of the substrate 16 (see FIG. 1B). The second gap G2 communicates with the back cavity BC and the vent hole 122. Accordingly, the back cavity BC communicates with the atmospheric pressure space through the second gap G2, the vent hole 122, the first gap G1, and the through hole H1. Of the second gap G2, the vent hole 122, the first gap G1, and the through hole H1, the acoustic resistance of the second gap G2 is the highest. The acoustic resistance of the second gap G2 increases as the height of the second gap G2 is decreased (that is, the height of the convex portion 123 is decreased) and the width of the edge of the diaphragm 120 and the edge of the substrate 16 is increased. In particular, the sensitivity of the low range is improved.

  As shown in FIGS. 1A and 2B, a connecting portion 121 extends outward from the outer periphery of the circular diaphragm 120. Diaphragm 120 is connected to pad 112 by connecting portion 121. Since the distal end portion of the connecting portion 121 is joined to the first spacer film 15, the diaphragm 120 is stretched over the through hole H3. Since the connecting portion 121 has a belt shape whose contour is bent, the elastic coefficient is small in the radial direction of the diaphragm 120. Therefore, the internal stress of the diaphragm 120 portion of the diaphragm electrode film 14 is released by the connecting portion 121. For this reason, the displacement with respect to the pressure of the diaphragm 120 becomes large, and the sensitivity increases in the entire region.

  As shown in FIG. 1A, the diaphragm 120 has a convex portion 123 that protrudes toward the substrate 16. The convex portion 123 may be constituted by the diaphragm electrode film 14 or may be constituted by another deposited film bonded to the diaphragm electrode film 14. The tip of the convex portion 123 of the diaphragm 120 is in contact with the surface of the substrate 16. For this reason, the height of the second gap G <b> 2 between the diaphragm 120 and the substrate 16 is maintained constant by the convex portion 123. The upper and lower positional relationship between the convex portion 123 of the diaphragm 120 and the convex portion 101 of the cantilever 100 may be a relationship that overlaps each other or a relationship that does not overlap.

2. Manufacturing Method The condenser microphone 1 is manufactured by application of process technology of a semiconductor device. Specifically, the structure shown in FIG. 1 is formed by sequentially depositing a thin film on the substrate 16 which is a bulk material and forming a gap by etching or lift-off.

  FIG. 2A is a schematic cross-sectional view showing an intermediate in the manufacturing process of the condenser microphone 1. A first spacer film 15, a diaphragm electrode film 14, a second spacer film 13, a plate electrode film 12, and a compression film 11 are formed on a substrate 16, and the diaphragm electrode film 14, the plate electrode film 12, and the compression film 11 are formed. Is patterned in a completed state. When the first spacer film 15 and the second spacer film 13 are selectively removed by isotropic etching in a state where the through hole H4 is formed in the substrate 16 by Deep-RIE or the like and the compressed film 11 is protected by the photoresist, The condenser microphone 1 shown in FIG. 1 can be formed. The shape of the through hole H3 of the first spacer film 15 and the shape of the through hole H2 of the second spacer film 13 are determined by the shape of the opening 161 of the substrate 16 and the shapes of the through holes H1 and the slits S of the plate electrode film 12.

  The convex portion 123 may be formed by forming a concave portion by etching in the first spacer film 15 that is directly below the convex portion 123 and filling the concave portion with the diaphragm electrode film 14, or different from the diaphragm electrode film 14. The diaphragm electrode film 14 may be deposited after the concave portion is filled with an insulating or conductive deposited film and the portion protruding from the concave portion of the deposited film is removed by planarization. Similarly, the convex portion 101 can be formed by using the concave portion formed in the second spacer film 13 that is immediately below the convex portion 101 as a mold.

3. Operation and Effect In the state shown in FIG. 2A, different internal stresses are generated in the film thickness direction at the portions of the plate electrode film 12 and the compression film 11 that become the cantilever 100. That is, as described above, stronger internal stress is generated in the compression direction in the compression film 11 than in the plate electrode film 12 close to the diaphragm electrode film 14. For this reason, when the through-hole H3 is formed in the first spacer film 15 and the through-hole H2 is formed in the second spacer film 13, the cantilever 100 is bent in a direction in which the tip portion approaches the diaphragm 120, and the diaphragm 120 The convex portion 101 in contact with the substrate pushes the diaphragm 120 toward the substrate 16. As a result, the first gap G1 between the diaphragm 120 and the electrode plate 110 is expanded, and the second gap G2 between the diaphragm 120 and the substrate 16 is narrowed. At this time, in the diaphragm electrode film 14, since the bent strip-shaped connecting portion 121 extends in the radial direction of the diaphragm 120, the internal stress of the diaphragm 120 decreases without increasing in the tensile direction. When the tip of the convex portion 123 of the diaphragm 120 contacts the substrate 16, the cantilever beam 100 and the connecting portion 121 are stabilized in the shape shown in FIGS. 1A and 1B.

  The height of the second gap G2, which is the maximum acoustic resistance in the space connecting the atmospheric pressure space and the back cavity BC, is determined by the height of the convex portion 123 of the diaphragm 120. The width of the second gap G2 (diameter direction length of the diaphragm) is determined by the width of the diaphragm 120 protruding from the opening 161 of the back cavity BC. The low frequency sensitivity characteristics of the condenser microphone 1 are governed by the height and width of the second gap G2 and the volume of the back cavity.

  According to the present embodiment, the height of the second gap G2 that governs the sensitivity characteristics in the low range is based on the distance between the diaphragm 120 and the substrate 16 immediately after the diaphragm electrode film 14 is deposited on the first spacer film 15. Is also getting smaller. The height of the first gap G1 between the diaphragm 120 and the electrode plate 110, which correlates with the stability against mechanical vibration and the rated pressure, is larger than the film thickness of the second spacer film 13 as a result of the deformation of the cantilever beam 100. It has become. That is, according to this embodiment, since the internal stress of the deposited film is used to set the height of the gap, the second gap G2 can be narrowed while widening the first gap G1. Therefore, according to the present embodiment, the rated pressure can be increased and the stability can be increased while increasing the sensitivity in the low frequency range, and the condenser microphone 1 in which sensitivity and stability are balanced in a high dimension is realized.

4). Other Embodiments FIG. 3A and FIG. 3B are schematic cross-sectional views showing other embodiments for forming the second gap G2. 4 and 5 are schematic plan views showing other embodiments for forming the second gap G2. 3A and 3B correspond to 1A and 1B shown in FIG. 1C, respectively. As shown in FIGS. 3A, 3B and 4 and 5, the second gap G <b> 2 may be formed by a groove 125 extending in the radial direction of the diaphragm 120 at the edge of the diaphragm 120. Further, the width of the groove 125 may be narrow as shown in FIG. 4 or may be wide as shown in FIG. 5, and can be appropriately designed so as to obtain an appropriate acoustic resistance. One end of the groove 125 is connected to the vent hole 122, and the other end is connected to the opening 161 of the back cavity BC. In this case, the height of the second gap G2 is determined by the depth of the groove 125. The groove 125 can be formed by forming the sacrificial film 17 corresponding to the groove 125 on the substrate 16 before depositing the diaphragm electrode film 14 as shown in FIG. 3C. The sacrificial film 17 is preferably made of a material that can be etched simultaneously with the first spacer film 15 and the second spacer film 13.

  6A and 6B are schematic cross-sectional views showing another embodiment for forming the second gap G2. FIG. 7 is a schematic plan view showing another embodiment for forming the second gap G2. 6A and 6B correspond to 1A and 1B shown in FIG. 1C, respectively. As shown in FIGS. 6A, 6B, and 7, the second gap G2 may be formed by a groove 165 that extends outward from the opening 161 at the edge of the substrate 16. One end of the groove 165 is connected to the vent hole 122, and the other end is connected to the opening 161 of the back cavity BC. In this case, the height of the second gap G2 is determined by the depth of the groove 165. As shown in FIG. 6C, the groove 165 can be formed by forming the groove 165 in the substrate 16 before depositing the first spacer film 15 and forming the sacrificial film 18 filling the groove 165. The sacrificial film 18 is preferably made of a material that can be etched simultaneously with the first spacer film 15 and the second spacer film 13.

  FIG. 8A and FIG. 8B are schematic cross-sectional views showing other embodiments for forming the first gap G1 and the second gap G2. 8A and 8B correspond to 1A shown in FIG. 1C. As shown in FIG. 8A, the height of the first gap G <b> 1 may be determined by integrating the diaphragm 120 and the convex portion 101 and bringing the tip of the convex portion 101 into contact with the cantilever beam 100. As shown in FIG. 8A, the height of the second gap G2 (see FIG. 1B) may be determined by integrating the substrate 16 and the convex portion 123 and bringing the diaphragm 120 into contact with the tip of the convex portion 123. That is, the convex portion 123 may be formed of a deposited film, and the back surface of the deposited film may be bonded to the substrate 16. Further, as shown in FIG. 8B, the convex portions need not be formed on the cantilever 100 or the diaphragm 120.

  In addition, the electrode plate 110 and the diaphragm 120 may have a single-layer structure in which one part is insulative or a multi-layer structure in which one or more layers are conductive. The diaphragm 120 and the electrode plate 110 do not have to be circular, but may be rectangular, for example. The cantilever 100 may be constituted by a deposited film in a layer different from the plate electrode film 12, for example, a layer between the plate electrode film 12 and the diaphragm electrode film 14.

  Furthermore, the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, the materials, dimensions, film forming methods, and pattern transfer methods shown in the above embodiments are merely examples, and descriptions of addition and deletion of processes and replacement of process orders that are obvious to those skilled in the art are omitted. ing. Further, the present invention can be applied to various electrostatic pressure transducers in addition to condenser microphones.

(1A) and (1B) are typical sectional views concerning the embodiment of the present invention. (1C) is a top view concerning the embodiment of the present invention. (2A) is a schematic sectional view according to an embodiment of the present invention. (2B) is a top view concerning the embodiment of the present invention. (3A), (3B), and (3C) are typical sectional drawings concerning embodiment of this invention. The typical top view concerning the embodiment of the present invention. The typical top view concerning the embodiment of the present invention. (6A), (6B) and (6C) are schematic sectional views according to the embodiment of the present invention. The typical top view concerning the embodiment of the present invention. (8A) And (8B) is typical sectional drawing concerning embodiment of this invention.

Explanation of symbols

1: condenser microphone, 11: compression film, 12: plate electrode film, 13: second spacer film, 14: diaphragm electrode film, 15: first spacer film, 16: substrate, 17: sacrificial film, 18: sacrificial film, 100: cantilever, 101: convex portion, 110: electrode plate, 112: pad, 120: diaphragm, 121: connection portion, 122: vent hole, 123: convex portion, 124: pad, 125: groove, 130: guard Electrode, 131: Pad, 161: Opening, 162: Through hole, 165: Groove, BC: Back cavity, G1: First gap, G2: Second gap, H1: Through hole, H2: Through hole, H3: Through hole , H4: Through hole, S: Slit

Claims (11)

A substrate,
An electrode plate comprising a deposited film on the substrate;
A diaphragm formed of a deposited film having a gap with the electrode plate and forming a counter electrode opposed to the electrode plate with the gap in between;
A cantilever made of a deposited film deposited in a layer closer to the electrode plate than the diaphragm and pushing the diaphragm in a state of being bent in a direction approaching the diaphragm from the proximal end portion toward the distal end portion due to internal stress When,
An electrostatic pressure transducer comprising: The substrate forms an opening in the back cavity;
The deposited film forming the electrode plate has a first vent hole,
A second gap that functions as an acoustic resistance between the back cavity and the first vent is between the edge of the diaphragm and the edge of the substrate;
Outside the opening of the back cavity of the deposited film forming the diaphragm, a second ventilation hole communicating the first ventilation hole and the second gap is formed,
The gap between the electrode plate and the diaphragm communicates with the first vent;
The electrostatic pressure transducer according to claim 1. The diaphragm has a convex portion whose tip is in contact with the substrate and forms the second gap.
The electrostatic pressure transducer according to claim 2. The back surface of the convex portion made of a deposited film that is in contact with the diaphragm and forms the second gap is bonded to the substrate.
The electrostatic pressure transducer according to claim 2. In the substrate, a groove forming the second gap is formed outward from the opening of the back cavity.
The electrostatic pressure transducer according to claim 2. A plurality of the second vent holes are formed,
The deposited film forming the diaphragm has a belt-like contour bent between the adjacent second vent holes,
The electrostatic pressure transducer according to claim 2. The cantilever is composed of a multilayer film.
The electrostatic pressure transducer according to claim 1. The cantilever and the electrode plate are at least partially made of a common deposited film,
The electrostatic pressure transducer according to claim 1. The cantilever beam has a convex portion at the tip portion that protrudes toward the diaphragm and the tip is in contact with the diaphragm.
The electrostatic pressure transducer according to claim 1. The diaphragm has a convex portion that protrudes toward the cantilever and is in contact with the tip of the cantilever.
The electrostatic pressure transducer according to claim 1. A microphone,
The electrostatic pressure transducer according to any one of claims 1 to 10.

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