CN214154840U

CN214154840U - MEMS microphone chip

Info

Publication number: CN214154840U
Application number: CN202022824858.3U
Authority: CN
Inventors: 柏杨; 赵转转; 王凯杰
Original assignee: Ruisheng Technology Nanjing Co Ltd
Current assignee: AAC Technologies Holdings Nanjing Co Ltd; Ruisheng Technology Nanjing Co Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2021-09-07
Anticipated expiration: 2030-11-30
Also published as: WO2022110415A1

Abstract

The utility model provides a MEMS microphone chip, which comprises a substrate with a back cavity, a vibrating diaphragm arranged on the substrate, and a back plate covering the vibrating diaphragm and having an inner cavity with the vibrating diaphragm; the vibrating diaphragm comprises a sensing area and a non-sensing area, wherein the sensing area is located in the middle, the non-sensing area surrounds the sensing area and is arranged in a gap mode with the sensing area to form a vibrating diaphragm slit, the sensing area comprises a body portion and a plurality of first protruding portions, the first protruding portions extend from the edge of the body portion to the direction of the non-sensing area to form the first protruding portions, the non-sensing area comprises a main portion, the main portion is arranged at intervals with the body portion, the main portion is matched with the first protruding portions to recess towards the direction far away from the body portion to form a plurality of first groove portion slits, the first groove portion slits comprise first gaps formed between the body portion and the main portion and second gaps formed between the first protruding portions and the first groove portions, and the first gaps are communicated with the second gaps. The utility model discloses the length of vibrating diaphragm slit has been increased to reduce the regional acoustic impedance of vibrating diaphragm slit, improve the performance of MEMS microphone chip low frequency decay.

Description

MEMS microphone chip

[ technical field ] A method for producing a semiconductor device

The utility model relates to an acoustoelectric technology field especially relates to a MEMS microphone chip.

[ background of the invention ]

The existing capacitive MEMS microphone chip is composed of a capacitive part and a base part. Specifically, the chip structure comprises a substrate with a back cavity, and a vibrating diaphragm and a fixed back plate which are positioned on the upper part of the substrate, wherein the vibrating diaphragm and the fixed back plate form a capacitance system. When sound pressure acts on the diaphragm, the diaphragm has pressure difference to the back plate and the two sides back to the back plate, so that the diaphragm moves towards the direction close to the back plate or away from the back plate, the change of capacitance between the diaphragm and the back plate is caused, the conversion from sound signals to electric signals is realized, and the above operation principle is the operation principle of the MEMS microphone chip.

In the existing chip structure, the diaphragm is divided into an induction diaphragm area and a non-induction diaphragm area according to functions, and the two areas are divided by a diaphragm slit, wherein the induction diaphragm area participates in signal output as a vibrating electrode, and the non-induction diaphragm area does not participate in signal output. In the application of actual terminal products, different microphone low-frequency attenuation performances are required to be applied to different terminals due to different module algorithms of a development board matched with an MEMS microphone chip.

When designing a MEMS microphone chip, a slit separation is usually provided between the inductive diaphragm region and the non-inductive diaphragm region or a bleed hole is provided at the center of the diaphragm to adjust low-frequency attenuation performance, and the diaphragm slits are mutually parallel straight lines, which are parallel to the boundary line between the substrate and the back cavity. Therefore, the existing chip structure has to be further improved in low frequency sensitivity, signal-to-noise ratio and reliability.

[ Utility model ] content

An object of the utility model is to provide a MEMS microphone chip that provides low frequency decay performance.

In order to achieve the above object, the present invention provides an MEMS microphone chip, which includes a substrate having a back cavity, a vibrating diaphragm disposed on the substrate, and a back plate covering the vibrating diaphragm and having an inner cavity spaced from the vibrating diaphragm; the diaphragm comprises a sensing area and a non-sensing area, the sensing area is located in the middle of the diaphragm and the non-sensing area surrounds the sensing area and is arranged in a gap mode with the sensing area to form a diaphragm slit, the sensing area comprises a body portion and a plurality of first protruding portions, the first protruding portions extend from the edge of the body portion to the direction of the non-sensing area to form the first protruding portions, the non-sensing area comprises a body portion, the body portion is arranged at intervals with the body portion, the body portion is matched with the first protruding portions to recess towards the direction far away from the body portion to form a plurality of first groove portions, the slit comprises first gaps formed between the body portion and second gaps formed between the first protruding portions and the first groove portions, and the first gaps are communicated with the second gaps.

Preferably, the non-sensing area further includes a plurality of second protruding portions extending from the main body portion to the main body portion, the main body portion is recessed in a direction away from the main body portion to cooperate with the second protruding portions to form a plurality of second groove portions, a third gap is formed between the second protruding portions and the second groove portions, and the third gap is communicated with the first gap and the second gap and encloses the slit.

Preferably, the MEMS microphone chip further includes a first supporting member interposed between the main body portion and the substrate, and a second supporting member interposed between the main body portion and the substrate.

Preferably, the first supporting member is annular and surrounds the periphery of the main body, and the second supporting member and the first supporting member are arranged at intervals and supported on two opposite sides of the main body in a columnar manner.

Preferably, the first protruding portion and the second protruding portion are arranged in a staggered manner along the extending direction of the first gap.

Preferably, the back plate has a through hole formed therethrough.

Preferably, at least part of the through holes are arranged opposite to the first gap.

Preferably, the second protrusion covers at least part of the through hole in an orthographic projection of the back plate along the vibration direction of the diaphragm.

Preferably, the first protruding portion covers at least a part of the through hole in an orthographic projection of the back plate along the vibration direction of the diaphragm.

Preferably, the edges of the first and second protrusions are parallel to each other and are a broken line or a curved line.

The beneficial effects of the utility model reside in that: the MEMS microphone chip is provided, under the condition that the width of a diaphragm slit is the same as that of the existing structure, the length of the diaphragm slit is increased by arranging the bulge part and the groove part corresponding to the bulge part, so that the acoustic impedance of the diaphragm slit area is reduced, and the low-frequency attenuation performance of the MEMS microphone chip is improved; and need not to set up the low frequency decay performance that loses heart regulation microphone in the central point of vibrating diaphragm position, avoided setting up in vibrating diaphragm central point and disappointing the hole, rather than the risk that the just base plate sound hole introduced foreign particles.

[ description of the drawings ]

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

fig. 2 is an exploded view of the MEMS microphone chip of the present invention;

FIG. 3 is a cross-sectional view of the MEMS microphone chip of FIG. 1 taken along the A-A direction;

fig. 4 is a top view of a diaphragm according to an embodiment of the present invention;

fig. 5 is a top view of a diaphragm provided in the second embodiment of the present invention;

FIG. 6 is an enlarged view of a portion of area A of FIG. 5;

fig. 7 is a top view of a diaphragm provided in the third embodiment of the present invention;

FIG. 8 is an enlarged partial view of the area B in FIG. 7;

fig. 9 is a schematic view illustrating a partial projection and an enlargement of a diaphragm provided by the fourth embodiment of the present invention on a plane where a back plate is located;

fig. 10 is a schematic view illustrating a partial projection and an enlargement of a diaphragm on a plane where a back plate is located according to a fifth embodiment of the present invention;

fig. 11 is a schematic view illustrating a partial projection and enlargement of a diaphragm provided in a sixth embodiment of the present invention on a plane where a back plate is located;

fig. 12 is a schematic view illustrating a partial projection and an enlargement of a diaphragm provided by the seventh embodiment of the present invention on a plane where a back plate is located;

fig. 13 is a schematic view illustrating a partial projection and an enlargement of a diaphragm on a plane where a back plate is located according to an eighth embodiment of the present invention;

fig. 14 is a schematic view of a partial projection and enlargement of the diaphragm on the plane where the back plate is located according to the ninth embodiment of the present invention.

[ detailed description ] embodiments

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

It should be noted that all the directional indicators (such as upper, lower, left, right, front, back, inner, outer, top, bottom … …) in the embodiments of the present invention are only used to explain the relative position between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

Example one

Referring to fig. 1 to 4, the present invention provides a MEMS microphone chip 100, wherein the chip 100 includes a substrate 10 having a back cavity 12, and a diaphragm 20 and a backplate 30 sequentially disposed on a surface of the substrate 10.

The substrate 10 includes an annular base 11 enclosed into the back cavity 12, the diaphragm 20 and the back plate 30 are fixed to the annular base 11, the diaphragm 20 is disposed between the substrate 10 and the back plate 30, and a cavity is formed between the diaphragm 20 and the back plate 30; the diaphragm 20 and the substrate 10 opposite to the diaphragm 20 form a first vibration space at an interval, and the diaphragm 20 and the back plate 30 form a second vibration space at an interval.

The back plate 30 is fixed to the substrate 10 by a support portion 40, and the support portion 40 is located at the outer side of the diaphragm 20.

The diaphragm 20 and the backplate 30 constitute a capacitive system.

When a pressure (sound wave) acts on the diaphragm 20 through the plurality of through holes 31 penetrating the backplate 30, the diaphragm 20 vibrates in a direction toward and away from the backplate 30 to cause a change in capacitance of a capacitor between the diaphragm 20 and the backplate 30. Therefore, an electric signal corresponding to the change in pressure (sound wave) can be generated, which is output through an external circuit connected to the capacitance system, eventually realizing the function of a microphone.

Referring to fig. 4, the diaphragm 20 includes a sensing region 21 and a non-sensing region 22 spaced around the sensing region 21. The non-induction area 22 surrounds the induction area 21, the induction area 21 and the non-induction area 22 are arranged at intervals to form a communicated diaphragm slit 23, and the non-induction area 22 is fixed with the annular base 11 of the substrate 10.

The sensing area 21 includes a main body 211 and a plurality of first protrusions 212, and the first protrusions 212 are formed by extending from an edge 21a of the main body 211 toward the non-sensing area 22. The non-sensing area 22 includes a main body 221 spaced apart from the main body 211, the main body 221 is recessed in a direction away from the main body 211 to form a plurality of first groove portions 222, and the first groove portions 222 are matched with the corresponding first protruding portions 212.

The diaphragm slit 23 includes a first gap 231 formed between the body portion 211 and the body portion 221, and a second gap 232 formed between the first protrusion portion 212 and the first groove portion 222, and the first gap 231 communicates with the second gap 232.

Under the condition that the width of the diaphragm slit 23 is the same as that of the existing structure, by arranging the first protruding portion 212 and the first groove portion 222 corresponding to the first protruding portion, the length of the diaphragm slit 23 is increased, so that the acoustic impedance of the diaphragm slit 23 area is reduced, and the performance of low-frequency attenuation of the MEMS microphone chip 100z is improved; and need not to set up the low frequency decay performance of disappointing hole regulation microphone in the central point of vibrating diaphragm 20, avoided setting up disappointing hole in vibrating diaphragm 20 central point, rather than the risk that the just base plate sound hole introduces external particulate matter.

The utility model discloses a MEMS microphone chip, under the condition of blowing of loud sound pressure or little air current, response diaphragm district 21 lifts up from the position of vibrating diaphragm slit 23, has increased the length on disappointing border and the area that loses heart, promotes the chip structure and resists the ability of blowing.

In this embodiment, the edge of the first protrusion portion 212 and the edge of the first groove portion 222 corresponding to the first protrusion portion 212 are broken lines or curved lines parallel to each other. That is, the orthogonal projection of the second gap 232 formed by the first protrusion 212 and the corresponding first groove 222 along the vibration direction of the diaphragm 20 is a broken line or a curved line parallel to each other.

In this embodiment, the widths of the first protruding portions 212 are equal, or the widths of the first protruding portions 212 are not equal.

In this embodiment, a plurality of the first protruding portions 212 are disposed at equal intervals, or a plurality of the first protruding portions 212 are disposed at unequal intervals.

Further preferably, referring to fig. 2, the MEMS microphone chip further includes a first supporting member 41 interposed between the main body portion 221 and the substrate 10, and a second supporting member 42 interposed between the main body portion 211 and the substrate 10, and heights of the first supporting member and the second supporting member along the vibration direction of the diaphragm 20 are the same.

Preferably, the first supporting member 41 is annular and surrounds the periphery of the main body 221, and the second supporting member 42 and the first supporting member 41 are spaced and supported on two opposite sides of the main body 211 in a cylindrical shape.

Example two

Referring to fig. 5 to 6, a difference between the second embodiment and the first embodiment is that the non-sensing area 22 further includes a plurality of second protruding portions 223 extending from the edge 22a of the main body 221 toward the main body 211, and the main body 211 of the sensing area 21 is recessed toward a direction away from the main body 221 to form a plurality of second groove portions 213 in cooperation with the second protruding portions 223. By arranging the second protrusion portion 223 and the corresponding second groove portion 213, the second protrusion portion 223 and the second groove portion 213 are spaced to form a third gap 233, and the third gap 233 is communicated with the first gap 231 and the second gap 232 and encloses the diaphragm slit 23, so as to further increase the length of the diaphragm slit 23, reduce the acoustic impedance of the diaphragm slit 23 area, and improve the low-frequency attenuation performance of the MEMS microphone chip.

In the present embodiment, the edge of the first protrusion portion 212 and the edge of the first groove portion 222 corresponding to the first protrusion portion 212 are parallel broken lines or curved lines, and the edge of the second protrusion portion 223 and the edge of the second groove portion 213 corresponding to the second protrusion portion 223 are parallel broken lines or curved lines. That is, the second gap 232 formed by the first protrusion portion 212 and the corresponding first groove portion 221, and the third gap 233 formed by the second protrusion portion 223 and the corresponding second groove portion 213 are broken lines or curved lines parallel to each other in the orthogonal projection along the vibration direction of the diaphragm 20.

In this embodiment, the widths of the first protruding portions 212 and the second protruding portions 223 are equal, or the widths of the first protruding portions 212 and the second protruding portions 222 are not equal.

In this embodiment, a plurality of the first protrusions 212 and the second protrusions 223 are disposed at equal intervals, or a plurality of the first protrusions 212 and the second protrusions 223 are disposed at unequal intervals.

Preferably, the first protruding portions 212 and the second protruding portions 223 are sequentially arranged in a staggered manner along the extending direction of the first gap 231, that is, the first protruding portions 212 and the second protruding portions 223 are sequentially and alternately arranged on two sides of the extending direction of the first gap 231.

EXAMPLE III

Referring to fig. 7 to 8, a difference between the third embodiment and the first embodiment is that the non-sensing area 22 further includes a plurality of second protruding portions 223 extending from the edge 22a of the main body 221 toward the main body 211, and the main body 211 of the sensing area 21 is recessed toward a direction away from the main body 221 to form a plurality of second groove portions 213 in cooperation with the second protruding portions 223. By arranging the second protrusion portion 223 and the corresponding second groove portion 213, the second protrusion portion 223 and the second groove portion 213 are spaced to form a third gap 233, and the third gap 233 is communicated with the first gap 231 and the second gap 232 and encloses the diaphragm slit 23, so as to further increase the length of the diaphragm slit 23, reduce the acoustic impedance of the diaphragm slit 23 area, and improve the low-frequency attenuation performance of the MEMS microphone chip.

Preferably, the first protruding portions 212 and the second protruding portions 223 are disposed in a non-staggered manner along the extending direction of the first gap 231, that is, the first protruding portions 212 and the second protruding portions 223 are disposed at intervals and are not alternately disposed on two sides of the extending direction of the first gap 231.

Example four

The difference between the fourth embodiment and the second embodiment is that: the back plate 30 is formed with a through hole 31 penetrating the back plate 30. Fig. 9 is an enlarged schematic view of the projection of the diaphragm on the plane of the backplate, in which the main body 211 and the main body 221 form projections 211 'and 221' on the plane of the backplate, respectively. The projections 212 ' of the first protruding portions and the projections 223 ' of the second protruding portions are arranged alternately, and the projections 223 ' of the second protruding portions cover at least part of the through holes 31, i.e. at least part of the through holes 31 are arranged opposite to the first gaps 231.

The gap 231 ' between the projection 211 ' of the main body part and the projection 221 ' of the main body part is opposite to the through hole 31, namely, the through hole 31 is opposite to the first gap 231, so that the squeeze film damping at the position can be effectively reduced, the noise is reduced, and the signal-to-noise ratio of the MEMS microphone chip is improved.

EXAMPLE five

The difference between the fifth embodiment and the third embodiment is that: the back plate 30 is formed with a through hole 31 penetrating the back plate 30. Fig. 10 is an enlarged schematic view of the projection of the diaphragm on the plane of the backplate, in which the main body 211 and the main body 221 form projections 211 'and 221' on the plane of the backplate, respectively. The projections 212 'of the first protruding portions and the projections 223' of the second protruding portions are disposed in a non-staggered manner, and the projections 212 'and 223' of the first protruding portions cover at least a part of the through holes 31, that is, at least a part of the through holes 31 are disposed opposite to the first gaps 231.

EXAMPLE six

The difference between the sixth embodiment and the second embodiment is that: the back plate 30 is formed with a through hole 31 penetrating the back plate 30. Fig. 11 is a schematic view showing a projection and an enlargement of the diaphragm on the plane of the backplate, in which the body 211 and the body 221 form projections 211 'and 221' on the plane of the backplate, respectively. The projections 212 ' of the first protruding parts are staggered with the projections 223 ' of the second protruding parts, and the projections 223 ' of the second protruding parts cover at least part of the through holes 31.

The projection 223' of the second protruding part is opposite to the through hole 31, namely, the through hole 31 is opposite to the second protruding part 223, so that the rapid release of gas is facilitated in the blowing and falling scenes, meanwhile, the squeeze film damping at the position can be effectively reduced, the noise is reduced, and the signal-to-noise ratio of the MEMS microphone chip is improved.

EXAMPLE seven

The seventh embodiment differs from the third embodiment in that: the back plate 30 is formed with a through hole 31 penetrating the back plate 30. Fig. 12 is an enlarged schematic view of the projection of the diaphragm on the plane of the backplate, in which the main body 211 and the main body 221 form projections 211 'and 221' on the plane of the backplate, respectively. The projections 212 ' of the first protruding portions and the projections 223 ' of the second protruding portions are arranged in a non-staggered manner, and the projections 223 ' of the second protruding portions cover at least part of the through holes 31.

Example eight

The difference between the eighth embodiment and the second embodiment is that: the back plate 30 is formed with a through hole 31 penetrating the back plate 30. Fig. 13 is an enlarged schematic view of the projection of the diaphragm on the plane of the backplate, in which the main body 211 and the main body 221 form projections 211 'and 221' on the plane of the backplate, respectively. The projections 212 ' of the first protruding portions and the projections 223 ' of the second protruding portions are arranged in a staggered manner, and the projections 212 ' of the first protruding portions cover at least part of the through holes 31.

The projection 212' of the first protruding part is opposite to the through hole 31, namely, the through hole 31 is opposite to the first protruding part 212, so that the rapid release of gas is facilitated in the blowing and falling scenes, meanwhile, the squeeze film damping at the position can be effectively reduced, the noise is reduced, and the signal-to-noise ratio of the MEMS microphone chip is improved.

Example nine

The difference between the ninth embodiment and the third embodiment is that: the back plate 30 is formed with a through hole 31 penetrating the back plate 30. Fig. 14 is an enlarged schematic view of the projection of the diaphragm on the plane of the backplate, in which the main body 211 and the main body 221 form projections 211 'and 221' on the plane of the backplate, respectively. The projections 212 ' of the first protruding portions and the projections 223 ' of the second protruding portions are disposed in a non-staggered manner, and the projections 212 ' of the first protruding portions cover at least a part of the through holes 31.

In the above embodiments, the inner and outer sides are opposite to the MEMS microphone chip, and the side facing the MEMS microphone chip is the inner side, and the side facing away from the MEMS microphone chip is the outer side.

The embodiment of the utility model provides a MEMS microphone chip is applicable to the MEMS microphone chip that has vibrating diaphragm, basement and back of the body chamber structure equally, like piezoelectric type and optical type MEMS microphone chip.

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. An MEMS microphone chip comprises a substrate with a back cavity, a vibrating diaphragm arranged on the substrate, and a back plate covering the vibrating diaphragm and having an inner cavity with the vibrating diaphragm at an interval; the vibrating diaphragm is characterized by comprising a sensing area positioned in the middle and a non-sensing area surrounding the sensing area and arranged with the sensing area in a spaced mode to form a vibrating diaphragm slit, wherein the sensing area comprises a body part and a plurality of first protruding parts extending from the edge of the body part to the direction of the non-sensing area, the non-sensing area comprises a body part arranged with the body part in a spaced mode, the body part is matched with the first protruding parts to recess towards the direction far away from the body part to form a plurality of first groove parts, the slit comprises a first gap formed between the body part and a second gap formed between the first protruding parts and the first groove parts, and the first gap is communicated with the second gap.

2. The MEMS microphone chip of claim 1, wherein: the non-induction area further comprises a plurality of second protruding portions formed by extending from the main body portion to the main body portion, the main body portion is recessed towards the direction far away from the main body portion and matched with the second protruding portions to form a plurality of second groove portions, third gaps are formed between the second protruding portions and the second groove portions at intervals, and the third gaps are communicated with the first gaps and the second gaps and enclose the slits.

3. The MEMS microphone chip of claim 1, wherein: the MEMS microphone chip further comprises a first supporting piece and a second supporting piece, wherein the first supporting piece is clamped between the main body part and the substrate, and the second supporting piece is clamped between the main body part and the substrate.

4. The MEMS microphone chip of claim 3, wherein: the first supporting piece is annular and wound on the periphery of the main body part, and the second supporting piece and the first supporting piece are arranged at intervals and are supported on two opposite sides of the main body part in a columnar shape.

5. The MEMS microphone chip of claim 2, wherein: the first and second protrusions are arranged alternately in the extending direction of the first gap.

6. The MEMS microphone chip of claim 5, wherein: the back plate is formed with a through hole.

7. The MEMS microphone chip of claim 6, wherein: at least part of the through holes are arranged opposite to the first gaps.

8. The MEMS microphone chip of claim 6 or 7, wherein: the second bulge covers at least part of the through hole in the orthographic projection of the back plate along the vibration direction of the diaphragm.

9. The MEMS microphone chip of claim 6 or 7, wherein: the first bulge covers at least part of the through hole in the orthographic projection of the back plate along the vibration direction of the diaphragm.

10. The MEMS microphone chip of claim 2, wherein: the edges of the first protruding part and the second protruding part are parallel to each other and are broken lines or curves.