CN214177566U

CN214177566U - Capacitance microphone

Info

Publication number: CN214177566U
Application number: CN202023351313.1U
Authority: CN
Inventors: 刘雨微; 孟珍奎; 张睿
Original assignee: AAC Acoustic Technologies Shenzhen Co Ltd
Current assignee: AAC Technologies Holdings Shenzhen Co Ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-09-10
Anticipated expiration: 2030-12-30

Abstract

The utility model provides a condenser microphone. The capacitive microphone comprises a substrate, a shell, an ASIC chip, a supporting wall and an MEMS chip, wherein the shell is covered on one side of the substrate, the ASIC chip is fixed on the substrate, the supporting wall is fixed on the substrate, the MEMS chip is fixed on the MEMS chip, the supporting wall and the substrate jointly enclose a front cavity, the MEMS chip comprises a vibrating diaphragm and a back plate, the substrate is provided with a sound inlet communicated with the front cavity, the supporting wall is provided with a bearing surface deviating from the side of the substrate and an inner wall surface adjacent to the bearing surface, the outline of the inner wall surface in the vibration direction of the vibrating diaphragm is square with a round chamfer, and the ratio of the radius length of the round chamfer to the width of the outline is 1:6-1: 3; the MEMS chip comprises a chip body and a cantilever which extends outwards from the outer edge of the chip body and corresponds to the round chamfer angle, and the cantilever is connected to the area, adjacent to the round chamfer angle, of the bearing surface. The scheme can improve the reliability of the vibrating diaphragm of the MEMS chip, and further improve the quality of the capacitive microphone.

Description

Capacitance microphone

[ technical field ] A method for producing a semiconductor device

The utility model belongs to the technical field of the electroacoustic conversion device, especially, relate to condenser microphone.

[ background of the invention ]

The capacitive microphone mainly utilizes the charge-discharge principle of capacitance between conductors, and senses sound pressure through an MEMS chip to directly convert the electrostatic voltage change between the conductors into an electric energy signal.

The capacitive microphone generally comprises a substrate, an ASIC chip and an MEMS chip which are arranged on one side of the substrate, and a shell which is covered on the substrate and surrounds the ASIC chip and the MEMS chip, wherein the MEMS chip is connected with a supporting wall arranged on the substrate, the MEMS chip, the supporting wall and the substrate jointly surround to form a front cavity, the substrate is provided with a sound inlet communicated with the front cavity, and sound enters from the sound inlet and then drives the front cavity to vibrate through air, so that a vibrating diaphragm is driven to vibrate to generate an electric energy signal corresponding to the sound.

The vibrating diaphragm in the MEMS chip among the correlation technique needs to be passed through cantilever beam structural connection on the support wall, and the cantilever beam is located the four corners position that closes on the ante-chamber, and the cantilever beam can become the stress weak point in machinery class reliability test, and the four corners position of ante-chamber is enclosed by the support wall, and nevertheless conventional support wall setting can make the vibrating diaphragm cantilever beam receive the degree that the stress weak point influences great, influences the reliability of vibrating diaphragm, and then influences the quality of condenser microphone.

[ Utility model ] content

An object of the utility model is to provide a condenser microphone can reduce the degree that the vibrating diaphragm received stress weakness influence among the MEMS chip, improves the reliability of vibrating diaphragm, and then improves condenser microphone's quality.

The technical scheme of the utility model as follows: the capacitive microphone comprises a substrate, a shell, an ASIC chip, a supporting wall and an MEMS chip, wherein the shell is covered on one side of the substrate and forms an accommodating space with the substrate in an enclosing manner, the ASIC chip is fixed on the substrate and is accommodated in the accommodating space, the supporting wall is fixed on the substrate and is positioned in the accommodating space, the MEMS chip is fixed on the supporting wall, is far away from the substrate side and is electrically connected with the ASIC chip, the MEMS chip, the supporting wall and the substrate jointly enclose a front cavity, the MEMS chip comprises a vibrating diaphragm and a back plate, the substrate is provided with a sound inlet hole communicated with the front cavity, the supporting wall is provided with a bearing surface and an inner wall surface, the bearing surface is far away from the substrate side, the inner wall surface is adjacent to the bearing surface and surrounds the peripheral side of the front cavity, the outline of the inner wall surface in the vibration direction of the vibrating diaphragm is square with a round chamfer, and the distance between two opposite square straight edges is the width of the outline, the ratio of the radius length of the round chamfer to the width of the profile is between 1:6 and 1: 3; the MEMS chip comprises a chip body arranged above the front cavity and a cantilever formed by extending from the outer edge of the chip body in parallel in the direction deviating from the chip body and corresponding to the round chamfer, and the cantilever is connected to the area of the bearing surface adjacent to the round chamfer.

Further, the ratio of the radius length of the rounded chamfer to the width of the profile is in the range of 1: 5-3: 10.

Further, the ratio of the radius length of the round chamfer to the width of the profile is 1: 4.

Further, the MEMS chip includes a diaphragm connected to the bearing surface, a backplate connected to the bearing surface and located at a side of the bearing surface of the diaphragm, and a backplate electrode attached to the backplate, the backplate being close to the diaphragm side and spaced from the diaphragm.

Further, the vibrating diaphragm comprises a first body arranged above the front cavity and a first support leg formed by extending from the edge of the first body and the corresponding position of the round chamfer angle in parallel towards the direction departing from the first body.

Further, the first supporting leg further comprises an oxide isolation layer arranged on the side of the area far away from the round chamfer, and the oxide isolation layer penetrates through the first supporting leg and is fixedly connected with the bearing surface.

Furthermore, the back plate comprises a connecting edge surrounding the outside of the vibrating diaphragm and fixed with the bearing surface and a connecting plate connected in the connecting edge and arranged opposite to the first body.

Furthermore, the back plate electrode is attached to the side, close to the first body, of the connecting plate, and comprises a second body right opposite to the first body and a second supporting leg extending outwards from the outer edge of the second body and right opposite to the first supporting leg.

Furthermore, a plurality of first through holes are uniformly formed in the thickness direction of the connecting plate, and second through holes which are opposite to the first through holes one by one are formed in the thickness direction of the second body.

Furthermore, the connecting edge comprises a supporting edge fixedly connected to the bearing surface and a connecting edge fixed to the supporting edge and deviating from the bearing surface side, and the edge of the connecting plate is connected to the inner side of the connecting edge.

The beneficial effects of the utility model reside in that: in the scheme, the outline of the inner wall surface of the supporting wall in the vibration direction of the vibrating diaphragm is square with a round chamfer, namely the corner position of the front cavity is an arc surface, so that the acoustic resistance can be reduced, and the sensitivity can be improved, and the ratio of the radius length of the round chamfer to the width of the outline is set to be 1:6-1:3, so that the stress influence on a first support pin which is connected with the supporting wall and corresponds to the corner position of the front cavity can be reduced, the degree of the vibrating diaphragm influenced by the stress weakness is reduced, the reliability of the vibrating diaphragm is improved, and the quality of the capacitor microphone is improved.

[ description of the drawings ]

Fig. 1 is a schematic structural diagram of a condenser microphone according to the present invention;

fig. 2 is a schematic perspective view of a support wall and an MEMS chip in a condenser microphone according to the present invention;

fig. 3 is a top view of a support wall and a MEMS chip in a condenser microphone according to the present invention;

fig. 4 is a cross-sectional view of the support wall and the MEMS chip of the condenser microphone of the present invention in the direction B-B in fig. 3;

fig. 5 is a schematic perspective exploded view of a support wall and an MEMS chip of the condenser microphone of the present invention;

fig. 6 is a top view of a support wall in the condenser microphone of the present invention;

FIG. 7 is an enlarged view of a detail of section A of FIG. 4;

fig. 8 is an enlarged view of a detail of section C of fig. 4.

[ detailed description ] embodiments

The present invention will be further described with reference to the accompanying drawings and embodiments.

With reference to fig. 1-8, a condenser microphone is provided, which includes a substrate 1, a housing 2 covering one side of the substrate 1 and enclosing with the substrate 1 to form an accommodation space, an ASIC (application Specific Integrated circuit) chip 5 fixed to the substrate 1 and accommodated in the accommodation space, a support wall 4 fixed to the substrate 1 and located in the accommodation space, and a MEMS chip 5 fixed to the support wall 4 and far away from the substrate 1 and electrically connected to the ASIC chip 3, the MEMS chip 5, the support wall 4 and the substrate 1 together enclosing to form a front cavity 10, the MEMS chip 5 including a diaphragm 51 and a back plate 52, the substrate 1 being provided with a sound inlet hole 11 communicating with the front cavity 10, the support wall 4 having a bearing surface 41 facing away from the substrate 1 side and an inner wall surface 42 abutting against the bearing surface 41 and surrounding the periphery of the front cavity 10, a contour 420 of the inner wall surface 42 in a vibration direction of the diaphragm 51 being square with a round chamfer 4201, the distance between two opposite straight sides of the square is the width L of the profile 420, and the ratio of the radius length r of the round chamfer 4201 to the width L of the profile 420 is 1:6-1: 3; the MEMS chip 5 includes a chip body 5a disposed above the front cavity 10 and a cantilever 5b extending from the outer edge of the chip body 5a corresponding to the rounded corner 4201 in parallel to the direction away from the chip body 5a, wherein the cantilever 5b is connected to the area of the carrying surface 41 adjacent to the rounded corner 4201.

In this embodiment, the contour 420 of the inner wall surface 42 of the support wall 4 in the vibration direction of the diaphragm 51 is square with a rounded chamfer 4201, that is, the corner of the front cavity 10 is a circular arc surface, which can reduce the acoustic resistance and improve the sensitivity, and the ratio of the radius length r of the rounded chamfer 4201 to the width L of the contour 420 is set to 1:6-1:3, and the cantilever 5b of the MEMS chip 5 is connected to the support wall 4 at the position corresponding to the corner of the front cavity 10.

In this embodiment, preferably, the ratio of the radius length r of the rounded chamfer 4201 to the width L of the profile 420 is 1: 5-3: 10. Specifically, in the embodiment, the ratio of the radius length r of the round chamfer 4201 to the width L of the profile 420 is 1:4, and in this ratio, the influence of the stress on the diaphragm 51 can be reduced to the greatest extent, so as to improve the reliability of the diaphragm 51, and further improve the quality of the condenser microphone.

The MEMS chip 5 includes a diaphragm 51 connected to the supporting surface 41, a back plate 52 connected to the supporting surface 41 and located on a side of the diaphragm 51 away from the supporting surface 41, and a back plate electrode 53 attached to the back plate 52 and close to the side of the diaphragm 51 and spaced from the diaphragm 51. When the diaphragm 51 vibrates, the diaphragm 51 and the back plate electrode 53 will be relatively displaced, so as to change the static voltage therebetween, and the change of the static voltage can be converted into an electric energy signal.

The diaphragm 51 includes a first body 511 disposed above the front cavity 10 and a first leg 512 extending from the edge of the first body 511 corresponding to the rounded corner 4201 in parallel to the direction away from the first body 511. The four corners of the first body 511 correspond to the rounded chamfer 4201 of the inner wall 42, that is, the four corners of the first body 511 extend to form a first leg 512, the first leg 512 further includes an oxide isolation layer 43 disposed on the side of the region far from the rounded chamfer 4201, the oxide isolation layer penetrates through the first leg 512 and is fixedly connected with the bearing surface 41, and the first body 511 is suspended on the region surrounded by the inner wall 42. Specifically, the oxide isolation layer 43 is a semicircular plate, and the corner position fillet of the oxide isolation layer 43 is transited, and the arc edge of the oxide isolation layer faces the direction away from the inner wall surface 42, and because the outward setting mode of the arc edge of the oxide isolation layer 43 can disperse the stress received by the first support 512, the stress influence is reduced, and the reliability of the diaphragm 51 is improved.

The back plate 52 includes a connecting edge 521 surrounding the outside of the diaphragm 51 and fixed with the carrying surface 41, and a connecting plate 522 connected to the inside of the connecting edge 521 and disposed opposite to the first body 511; the connecting edge 521 includes a supporting edge 5211 fixedly connected to the bearing surface 41 and a connecting edge 5212 fixed to the side of the supporting edge 5211 away from the bearing surface 41, and the edge of the connecting plate 522 is connected to the inner side of the connecting edge 5212. The attachment rim 521 is provided to isolate the diaphragm 51 and thereby protect the diaphragm 51.

The back plate electrode 53 is attached to the connecting plate 522 near the first body 511, and the back plate electrode 53 includes a second body 531 opposite to the first body 511 and a second leg 532 extending outward from an outer edge of the second body 531 and opposite to the first leg 512.

The connecting plate 522 has a plurality of first through holes 5221 uniformly formed in the thickness direction thereof, and the second body 531 has second through holes 5311 aligned with the first through holes 5221 one by one in the thickness direction thereof.

In this embodiment, the portion of the back plate 52 covering the first body 511, and the second body 531 together form a chip body 5 a; the portion of the back plate 52 covering the first leg 512, the first leg 512 and the second leg 532 together constitute a cantilever 5 b.

The above embodiments of the present invention are only described, and it should be noted that, for those skilled in the art, modifications can be made without departing from the inventive concept, but these all fall into the protection scope of the present invention.

Claims

1. A capacitance microphone comprises a substrate, a shell, an ASIC chip, a supporting wall and an MEMS chip, wherein the shell covers one side of the substrate and forms an accommodating space with the substrate in an enclosing mode, the ASIC chip is fixed on the substrate and is accommodated in the accommodating space, the supporting wall is fixed on the substrate and is located in the accommodating space, the MEMS chip is fixed on the supporting wall, is far away from the substrate side and is electrically connected with the ASIC chip, the MEMS chip, the supporting wall and the substrate are jointly enclosed to form a front cavity, the MEMS chip comprises a vibrating diaphragm and a back plate, and the substrate is provided with a sound inlet communicated with the front cavity, and the capacitance microphone is characterized in that: the supporting wall is provided with a bearing surface deviating from the base side and an inner wall surface which is adjacent to the bearing surface and surrounds the peripheral side of the front cavity, the outline of the inner wall surface in the vibration direction of the diaphragm is a square with a round chamfer, the distance between two opposite straight edges of the square is the width of the outline, and the ratio of the radius length of the round chamfer to the width of the outline is 1:6-1: 3;

the MEMS chip comprises a chip body arranged above the front cavity and a cantilever formed by extending from the outer edge of the chip body in parallel in the direction deviating from the chip body and corresponding to the round chamfer, and the cantilever is connected to the area of the bearing surface adjacent to the round chamfer.

2. A condenser microphone according to claim 1, wherein the ratio of the length of the radius of the rounded chamfer to the width of the profile is in the range of 1: 5-3: 10.

3. The condenser microphone of claim 2, wherein the ratio of the length of the radius of the rounded chamfer to the width of the profile is 1: 4.

4. The condenser microphone of any one of claims 1-3, wherein the MEMS chip comprises a diaphragm connected to the carrying surface, a back plate connected to the carrying surface and located on a side of the diaphragm away from the carrying surface, and a back plate electrode attached to the back plate and located close to the diaphragm side and spaced apart from the diaphragm.

5. The condenser microphone of claim 4, wherein the diaphragm comprises a first body disposed above the front cavity and a first leg extending from an edge of the first body corresponding to the rounded corner in parallel in a direction away from the first body.

6. The condenser microphone of claim 5, wherein the first leg further comprises an oxide isolation layer disposed on a side of the region away from the rounded corner, and the oxide isolation layer penetrates through the first leg and is fixedly connected to the carrying surface.

7. The condenser microphone of claim 5, wherein the back plate comprises a connecting edge surrounding the diaphragm and fixed to the carrying surface, and a connecting plate connected to the inside of the connecting edge and disposed opposite to the first body.

8. The condenser microphone of claim 7, wherein the back plate electrode is attached to the connecting plate near the first body, and the back plate electrode comprises a second body opposite to the first body and a second leg extending outward from an outer edge of the second body and opposite to the first leg.

9. The condenser microphone of claim 8, wherein the connecting plate has a plurality of first through holes uniformly formed in a thickness direction thereof, and the second body has second through holes aligned with the first through holes one by one in the thickness direction thereof.

10. The condenser microphone of claim 7, wherein the connecting edge comprises a supporting edge fixedly connected to the carrying surface and a connecting edge fixed to the supporting edge and facing away from the carrying surface, and the edge of the connecting plate is connected to the inner side of the connecting edge.