CN114390415A - MEMS microphone structure and manufacturing method thereof - Google Patents

Abstract

The invention provides an MEMS microphone structure and a manufacturing method thereof, wherein the MEMS microphone structure comprises a substrate, a vibrating diaphragm and a bracket, wherein a cavity penetrating through the substrate in the vertical direction is arranged in the substrate; the vibrating diaphragm is suspended above the cavity and comprises a folding structure, and the folding structure is bent back and forth in the vertical direction; the support is connected between the vibrating diaphragm and the substrate, and the distance between the folding structure and the center of the vibrating diaphragm is smaller than the distance between the support and the center of the vibrating diaphragm. According to the invention, the diaphragm comprises the folding structure for increasing the flexibility degree of the diaphragm and reducing the internal stress of the diaphragm, and the folding structure is bent at a right angle.

Description

A kind of MEMS microphone structure and its manufacturing method

technical field

The invention belongs to the technical field of microphones, and relates to a MEMS microphone structure and a manufacturing method thereof.

Background technique

Today's smart phones and smart speakers use microphones manufactured with MEMS (Micro-Electro-Mechanical System, Micro-Electro-Mechanical System) technology. This microphone has the characteristics of small size, low power consumption, excellent performance, good consistency, and easy assembly. The core component of a MEMS microphone is a flexible diaphragm that can vibrate back and forth. Both the flexibility of the diaphragm and the stress within the diaphragm will affect the final performance of the microphone.

SUMMARY OF THE INVENTION

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a MEMS microphone structure and a manufacturing method thereof, which are used to solve the problems that the diaphragm of the MEMS microphone is not soft enough and the internal stress of the diaphragm is high in the prior art.

In order to achieve the above purpose and other related purposes, the present invention provides a MEMS microphone structure, including:

a substrate, wherein the substrate is provided with a cavity penetrating the substrate in a vertical direction;

a diaphragm, suspended above the cavity, the diaphragm includes a folded structure, and the folded structure is bent back and forth in a vertical direction;

A bracket is connected between the diaphragm and the base plate, and the distance between the folded structure and the center of the diaphragm is smaller than the distance between the bracket and the center of the diaphragm.

Optionally, the folding structure is bent at a right angle.

Optionally, the bottom surface of the folded structure is lower than the bottom surface of the area of the diaphragm other than the folded structure.

Optionally, the diaphragm includes 2-10 of the folded structures arranged in sequence from the inside to the outside in the horizontal direction.

Optionally, the folded structure is in the form of a continuous ring or an intermittent ring.

Optionally, the ring shape includes a circular ring or a polygonal ring.

Optionally, the diaphragm is further provided with a vent hole, and the vertical projection of the vent hole on the substrate is located outside the cavity.

Optionally, the MEMS microphone structure further includes a back pole, the back pole is located above the vibrating membrane, and there is an air gap between the back pole and the vibrating membrane, and the back pole is provided with a plurality of The first acoustic hole of the back pole penetrates in the vertical direction, and the first acoustic hole communicates with the air gap.

Optionally, the MEMS microphone structure further includes a back plate, the back plate is connected to the substrate and the back electrode, and the back plate is provided with a plurality of second plates penetrating the back plate in the vertical direction. A sound hole, the second sound hole communicates with the first sound hole.

Optionally, the lower surface of the back plate is provided with a plurality of blocking blocks, the blocking blocks penetrate the back pole in the vertical direction, and the lower surface of the blocking blocks is lower than the lower surface of the back pole.

The present invention also provides a method for fabricating a MEMS microphone structure, comprising the following steps:

providing a substrate, and forming a first sacrificial layer on the substrate;

Forming grooves and through grooves in the first sacrificial layer, the grooves are opened from the upper surface of the first sacrificial layer and extend toward the substrate, but do not reach the substrate, and the through grooves are located in the first sacrificial layer. vertically penetrating the first sacrificial layer, and enclosing a bracket in the first sacrificial layer;

A diaphragm is formed on the first sacrificial layer, the diaphragm is filled into the groove and the through groove, and the diaphragm is bent back and forth in the area where the groove is located to form a folded structure, the The distance between the folded structure and the center of the diaphragm is smaller than the distance between the bracket and the center of the diaphragm;

forming a cavity in the substrate, the cavity penetrating the substrate in a vertical direction;

A portion of the first sacrificial layer is removed so that the diaphragm is suspended above the cavity, and the first sacrificial layer is not removed as part of the support.

Optionally, the side wall of the groove is at right angles to the bottom surface, and the folding structure is bent at right angles.

Optionally, 2-10 of the grooves are formed sequentially from the inside to the outside in the horizontal direction.

Optionally, the grooves comprise continuous annular grooves or intermittent annular grooves.

Optionally, the annular groove includes a circular annular groove or a polygonal annular groove.

Optionally, the method further includes the step of forming a vent hole in the diaphragm, and the vertical projection of the vent hole on the substrate is located outside the cavity.

Optionally, the following steps are also included:

forming a second sacrificial layer, the second sacrificial layer is located on the first sacrificial layer and covers the diaphragm;

forming a back electrode on the second sacrificial layer, and forming a plurality of first acoustic holes penetrating the back electrode in a vertical direction;

forming a backplane, the backplane is located on the substrate and covers the first sacrificial layer, the second sacrificial layer and the back electrode;

forming a second acoustic hole in the back plate, the second acoustic hole penetrates the back plate in a vertical direction and communicates with the first acoustic hole;

The second sacrificial layer is removed to obtain an air gap between the back electrode and the diaphragm.

Optionally, the following steps are also included:

forming a plurality of blocking block grooves in the second sacrificial layer;

forming a plurality of blocking block through grooves that penetrate the back pole in the vertical direction, the blocking block through grooves are opposite to the blocking block grooves in the vertical direction, and the back plate is also filled into the blocking block through grooves and the blocking block groove to form a blocking block.

As mentioned above, in the MEMS microphone structure and the manufacturing method thereof of the present invention, the diaphragm includes a folded structure for increasing the flexibility of the diaphragm and reducing the internal stress of the diaphragm, and the folded structure is bent at a right angle. When the number of folded structures is increased due to the good stress release effect, the present invention can effectively reduce the area of the diaphragm occupied by the folded regions compared with the arc-shaped structures.

Description of drawings

Figure 1 shows a cross-sectional view of a MEMS microphone structure.

FIG. 2 is a schematic cross-sectional view of the MEMS microphone structure of the present invention.

Figure 3 shows a schematic representation of the folded structure as a continuous square ring.

Figure 4 shows a schematic representation of a square ring with an interrupted folded structure.

Figure 5 shows a schematic view of the folded structure as a continuous ring.

Figure 6 shows a schematic view of a ring with an interrupted folded structure.

Figure 7 shows a schematic view of the folded structure as a continuous hexagonal ring.

Figure 8 shows a schematic view of a hexagonal ring with an interrupted folded structure.

FIG. 9 is a schematic diagram of forming a first sacrificial layer on a substrate according to the method for fabricating the MEMS microphone structure of the present invention.

FIG. 10 is a schematic diagram of forming a groove in the first sacrificial layer according to the method for fabricating the MEMS microphone structure of the present invention.

FIG. 11 is a schematic diagram of forming a through groove in the first sacrificial layer according to the method for fabricating the MEMS microphone structure of the present invention.

FIG. 12 is a schematic diagram of forming a diaphragm on the first sacrificial layer according to the method for fabricating the MEMS microphone structure of the present invention.

FIG. 13 is a schematic diagram of forming a vent hole in the diaphragm and removing the peripheral portion of the diaphragm according to the manufacturing method of the MEMS microphone structure of the present invention.

FIG. 14 is a schematic diagram illustrating the formation of the second sacrificial layer in the method for fabricating the MEMS microphone structure of the present invention.

FIG. 15 is a schematic diagram of forming a plurality of blocking block grooves in the second sacrificial layer according to the method for fabricating the MEMS microphone structure of the present invention.

16 is a schematic diagram illustrating the method for fabricating the MEMS microphone structure of the present invention by removing the peripheral portions of the first sacrificial layer and the second sacrificial layer to expose the substrate.

FIG. 17 is a schematic diagram of forming a back electrode on the second sacrificial layer for the fabrication method of the MEMS microphone structure of the present invention.

18 is a schematic diagram illustrating the formation of a plurality of first acoustic holes vertically penetrating the back electrode and a plurality of blocking block through-grooves vertically penetrating the back electrode by the method for fabricating the MEMS microphone structure of the present invention.

FIG. 19 shows a schematic diagram of forming a backplane for the method for fabricating the MEMS microphone structure of the present invention.

FIG. 20 is a schematic diagram of forming a second acoustic hole in the backplane and removing the peripheral portion of the backplane for the method of fabricating the MEMS microphone structure of the present invention.

FIG. 21 is a schematic diagram illustrating the thinning of the substrate by the method for fabricating the MEMS microphone structure of the present invention.

FIG. 22 is a schematic diagram of forming a cavity in a substrate according to a method for fabricating a MEMS microphone structure of the present invention.

23 shows the method for fabricating a MEMS microphone structure by removing a part of the first sacrificial layer so that the diaphragm is suspended above the cavity, and removing the second sacrificial layer to obtain an air gap between the back pole and the diaphragm schematic diagram.

Component label description

101 Substrate

102 Support structure

103 Diaphragm

104 Back pole

105 Backplane

106 Folding structure

201 Substrate

202 Diaphragm

203 bracket

204 cavity

205 Folding structure

206 Air vent

207 Back pole

208 Air Gap

209 First sound hole

210 Backplane

211 Second sound hole

212 Blocks

213 first sacrificial layer

214 groove

215 through slot

216 Second sacrificial layer

217 Block groove

218 Block through slot

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

See Figures 1 through 23. It should be noted that the diagrams provided in this embodiment are only to illustrate the basic concept of the present invention in a schematic way, so the diagrams only show the components related to the present invention rather than the number, shape and the number of components in the actual implementation. For dimension drawing, the type, quantity and proportion of each component can be changed at will in actual implementation, and the component layout may also be more complicated.

To increase the flexibility of the diaphragm and relieve stress within the diaphragm, the diaphragm of some MEMS microphones includes a folded structure, the exact shape of which depends on the process flow used to manufacture the structure. As shown in FIG. 1, it is a cross-sectional view of a MEMS microphone structure, including a substrate 101, a support structure 102, a diaphragm 103, a back pole 104 and a back plate 105, and the diaphragm 103 of the MEMS microphone structure has a folded structure 106, It is manifested as a protruding arc structure on the upper surface of the diaphragm 103. In order to achieve a better stress release effect, if the number of such arc structures is increased, a larger area of the diaphragm will be occupied. The invention improves the folded structure of the diaphragm, increases the flexibility of the diaphragm and releases the internal stress of the diaphragm without occupying more area of the diaphragm. The technical solutions of the present invention are described below through specific embodiments.

Example 1

In this embodiment, a MEMS microphone structure is provided. Please refer to FIG. 2 , which is a schematic cross-sectional structure diagram of the MEMS microphone structure, including a substrate 201 , a diaphragm 202 and a bracket 203 , wherein the substrate 201 is provided in a vertical direction. The diaphragm 202 is suspended above the cavity 204, and the diaphragm 202 includes a folded structure 205, and the folded structure 205 is bent back and forth in the vertical direction; The bracket 203 is connected between the diaphragm 202 and the base plate 201 , and the distance between the folded structure 205 and the center of the diaphragm 202 is smaller than the distance between the bracket 203 and the center of the diaphragm 202 . distance between.

Specifically, the substrate 201 is used to provide a process platform for the formation of the MEMS microphone structure, including but not limited to a silicon substrate, a germanium substrate, a silicon germanium substrate or a silicon carbide substrate, a silicon-on-insulator substrate or a germanium-on-insulator substrate, a glass substrate or III-V compound substrates (eg, gallium nitride substrates or gallium arsenide substrates, etc.). In this embodiment, the substrate 201 is a silicon substrate as an example. The bracket 203 is used to support the diaphragm 202, and its material includes but not limited to silicon oxide. The diaphragm 202 is used to vibrate under the air pressure generated by the sound, and its material includes but not limited to polysilicon.

Specifically, the folded structure 205 of the diaphragm 202 is used to increase the flexibility of the diaphragm and reduce the internal stress of the diaphragm. In this embodiment, the folding structure 205 is bent at a right angle. Compared with the arc-shaped folding structure, a single folding structure of the present invention occupies a smaller area. In the case of occupying the same area of the diaphragm, the number of folded structures in the diaphragm of the present invention can be more, and a better stress release effect can be achieved.

As an example, the vertical projection of the folded structure 205 on the substrate 201 may be located inside the cavity 204 , or may be located outside the cavity 204 , or may be partially located in the cavity 204 and partially located in the cavity 204 . It is located outside the cavity 204 and can be adjusted as required.

As an example, the bottom surface of the folded structure 205 is lower than the bottom surface of the area of the diaphragm other than the folded structure 205 (ie, the non-folded area).

As an example, the folded structure 205 may be a continuous ring or an intermittent ring, and the ring includes but is not limited to a circular ring or a polygonal ring.

As an example, please refer to FIGS. 3 to 8 , wherein FIG. 3 shows a schematic diagram of the folded structure 205 of the diaphragm 202 being a continuous square ring, and FIG. 4 shows the folded structure of the diaphragm 202 205 is a schematic diagram of a discontinuous square ring. FIG. 5 shows a schematic diagram of the folded structure 205 of the diaphragm 202 being a continuous ring. FIG. 6 shows that the folded structure 205 of the diaphragm 202 is broken. A schematic diagram of a continuous ring, FIG. 7 shows a schematic diagram of the folded structure 205 of the diaphragm 202 being a continuous hexagonal ring, and FIG. 8 shows a schematic diagram of the folded structure 205 of the diaphragm 202 being discontinuous Schematic diagram of a hexagonal ring.

It should be noted that only one of the folded structures 205 is shown in the diaphragm 202 in FIG. 3 to FIG. 8 , in other embodiments, the diaphragm 202 may also include a horizontal direction from the inside A plurality of the folded structures 205 arranged in sequence outside may include, for example, 2-10 of the folded structures 205. In FIG. 2, it is shown that the diaphragm 202 includes 3 arranged sequentially from the inside to the outside in the horizontal direction. The case of the folded structure 205 .

As an example, the diaphragm 202 is further provided with a vent hole 206 , and the vertical projection of the vent hole 206 on the substrate 201 is located outside the cavity 204 . The air vent hole 206 is used for releasing the air through the air vent hole 206 when the vibrating membrane 202 is impacted by high air pressure, thereby reducing the pressure that the vibrating membrane 202 needs to bear. The number and distribution of the vent holes 206 can be adjusted as required.

As an example, the MEMS microphone structure further includes a back pole 207, the back pole 207 is located above the diaphragm 202, and an air gap 208 is formed between the back pole 207 and the diaphragm 202, and the back pole 207 is located above the diaphragm 202. 207 is provided with a plurality of first acoustic holes 209 penetrating the back pole 207 in the vertical direction, and the first acoustic holes 209 communicate with the air gap 208 . The material of the back electrode 207 includes but is not limited to polysilicon.

As an example, the MEMS microphone structure further includes a back plate 210, the back plate 210 is connected to the substrate 201 and the back electrode 207, and the back plate 210 is provided with a plurality of vertically extending through the back plate The second acoustic hole 211 of the plate 210 communicates with the first acoustic hole 209 . The material of the back plate 210 includes but is not limited to silicon nitride.

As an example, the lower surface of the back plate 210 is provided with a plurality of blocking blocks 212, the blocking blocks 212 penetrate the back pole 207 in the vertical direction, and the lower surface of the blocking blocks 212 is lower than the back pole 207 to prevent the diaphragm 202 from adhering to the back pole 207 .

Specifically, the diaphragm 202, the air gap 208 and the back pole 207 are used to form a capacitor structure. When the microphone is working, the sound signal can enter the capacitor structure (in the air gap) through the sound hole, and can also Through the cavity 204 entering the capacitor structure, the distance between the diaphragm 202 and the back electrode 207 is changed, so that the capacitance value of the capacitor structure is correspondingly changed, and then the sound signal is converted into an electrical signal .

The diaphragm of the MEMS microphone structure of this embodiment includes a folded structure for increasing the flexibility of the diaphragm and reducing the internal stress of the diaphragm, and the folded structure is bent at a right angle. When the folded structure is added to achieve a better stress release effect When the number of structures is increased, compared with the arc structure, the present invention can effectively reduce the area of the diaphragm occupied by the folding area.

Embodiment 2

The present embodiment provides a method for fabricating a MEMS microphone structure, comprising the following steps:

Please refer to FIG. 9 , a substrate 201 is provided, and a first sacrificial layer 213 is formed on the substrate 201 by chemical vapor deposition, physical vapor deposition or other suitable methods. The materials of the first sacrificial layer 213 include but are not limited to two Silicon oxide.

Referring to FIG. 10 , a groove 214 is formed in the first sacrificial layer 213 by photolithography, etching or other suitable processes. The substrate 201 extends in the direction, but does not reach the substrate 201 .

As an example, the sidewalls of the grooves 214 are at right angles or substantially at right angles (within 10° deviation) from the bottom surface.

As an example, 2-10 grooves 214 may be formed in sequence from the inside to the outside in the horizontal direction, and the grooves 214 may be continuous annular grooves, intermittent annular grooves or other suitable shapes, so The annular groove includes, but is not limited to, a circular annular groove or a polygonal annular groove.

Referring to FIG. 11 , a through groove 215 is formed in the first sacrificial layer by photolithography, etching or other suitable processes. The bracket 203 is surrounded by the first sacrificial layer 213 .

Referring to FIG. 12 , a diaphragm 202 is formed on the first sacrificial layer 213 by chemical vapor deposition, physical vapor deposition or other suitable methods, and the diaphragm 202 is filled into the grooves 214 and the through grooves 215 , and the diaphragm 202 is bent back and forth in the area where the groove 214 is located to form a folded structure, and the distance between the folded structure and the center of the diaphragm is smaller than the bracket 203 and the center of the diaphragm the distance between. The material of the diaphragm 202 includes but is not limited to polysilicon.

It should be pointed out that the diaphragm 202 may partially fill the groove 214 or completely fill the groove 214, but in the area where the groove 214 is located, the diaphragm 202 is partially concave, A folded structure 205 that is bent back and forth is formed. In addition, since the side wall of the groove 214 is at a right angle or substantially at a right angle to the bottom surface, the folded structure 205 is a protruding portion whose lower surface edge is at or substantially a right angle, that is, the folded structure 205 is at a right angle Bend.

Referring to FIG. 13 , the vent holes 206 are formed in the diaphragm 202 by photolithography, etching or other suitable processes, and the peripheral portion of the diaphragm 202 is removed.

Referring to FIG. 14 , chemical vapor deposition, physical vapor deposition or other suitable methods are used to form a second sacrificial layer 216 , the second sacrificial layer 216 is located on the first sacrificial layer 213 and covers the diaphragm 202 . The material of the second sacrificial layer 216 includes but is not limited to silicon dioxide.

Referring to FIG. 15 , a plurality of blocking block grooves 217 are formed in the second sacrificial layer 216 by photolithography, etching or other suitable processes.

Referring to FIG. 16 , the peripheral portions of the first sacrificial layer 213 and the second sacrificial layer 216 are removed by photolithography, etching or other suitable processes to expose the substrate 201 .

Referring to FIG. 17 , the back electrode 207 is formed on the second sacrificial layer 216 by chemical vapor deposition, physical vapor deposition or other suitable methods. The material of the back electrode 207 includes but is not limited to polysilicon.

Referring to FIG. 18 , photolithography, etching or other suitable processes are used to form a plurality of first acoustic holes 209 penetrating the back electrode 207 in the vertical direction and a plurality of barriers penetrating the back electrode 207 in the vertical direction The block through groove 218 is opposite to the blocking block groove 217 in the vertical direction.

Referring to FIG. 19 , chemical vapor deposition, physical vapor deposition or other suitable methods are used to form a backplane 210 , the backplane 210 is located on the substrate 201 and covers the first sacrificial layer 213 and the second sacrificial layer 216 and the back pole; 207. The material of the back plate 210 includes but is not limited to silicon nitride. The back plate 210 is also filled into the blocking block through groove 218 and the blocking block groove 217 to form a blocking block 212 to prevent the diaphragm 202 from adhering to the back pole 207 during vibration after release. .

Referring to FIG. 20 , a second acoustic hole 211 is formed in the back plate 210 by photolithography, etching or other suitable processes, and the peripheral portion of the back plate 210 is removed. The second acoustic hole 211 is vertical The direction penetrates through the back plate 210 and communicates with the first acoustic hole 209 .

Referring to FIG. 21, the substrate 201 is thinned by chemical mechanical polishing or other suitable processes.

Referring to FIG. 22, deep reactive ion etching (DRIE) or other suitable processes are used to form a cavity 204 in the substrate 201, and the cavity 204 penetrates the substrate in the vertical direction; the vent hole 206 is in the The vertical projection on the substrate 201 is outside the cavity 204 .

Referring to FIG. 23, wet etching or other suitable process is used to remove a part of the first sacrificial layer 213 so that the diaphragm 202 is suspended above the cavity 204, and the second sacrificial layer is removed Step 216 , obtaining an air gap 208 between the back pole 207 and the diaphragm 202 , wherein the first sacrificial layer 213 is not removed as a part of the bracket 203 .

So far, a MEMS microphone structure has been produced. The MEMS microphone structure includes a diaphragm with a folded structure, which can increase the flexibility of the diaphragm and reduce the internal stress of the diaphragm, and the folded structure is bent at a right angle and occupies a relatively large area of the diaphragm. Small.

To sum up, in the MEMS microphone structure and its manufacturing method of the present invention, the diaphragm includes a folded structure for increasing the flexibility of the diaphragm and reducing the internal stress of the diaphragm, and the folded structure is bent at a right angle. When the number of folded structures is increased due to better stress release effect, the present invention can effectively reduce the area of the diaphragm occupied by the folded area compared to the arc-shaped structure. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

The above-mentioned embodiments merely illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed in the present invention should still be covered by the claims of the present invention.

Claims (18)

1. A MEMS microphone structure, comprising:

the substrate is provided with a cavity penetrating through the substrate in the vertical direction;

the vibrating diaphragm is suspended above the cavity and comprises a folding structure, and the folding structure is bent back and forth in the vertical direction;

the support is connected between the vibrating diaphragm and the substrate, and the distance between the folding structure and the center of the vibrating diaphragm is smaller than the distance between the support and the center of the vibrating diaphragm.

2. The MEMS microphone structure of claim 1, wherein: the folding structure is bent at a right angle.

3. The MEMS microphone structure of claim 1, wherein: the bottom surface of the folded structure is lower than the bottom surface of the region of the diaphragm except the folded structure.

4. The MEMS microphone structure of claim 1, wherein: the vibrating diaphragm comprises 2-10 folding structures which are sequentially arranged from inside to outside in the horizontal direction.

5. The MEMS microphone structure of claim 1, wherein: the folding structure is in a continuous ring shape or an interrupted ring shape.

6. The MEMS microphone structure of claim 5, wherein: the ring shape includes a circular ring or a polygonal ring.

7. The MEMS microphone structure of claim 1, wherein: and the vibrating diaphragm is also provided with an air leakage hole, and the vertical projection of the air leakage hole on the substrate is positioned outside the cavity.

8. The MEMS microphone structure of claim 1, wherein: the MEMS microphone structure further comprises a back pole, the back pole is located above the vibrating diaphragm, an air gap is formed between the back pole and the vibrating diaphragm, a plurality of first sound holes penetrating through the back pole in the vertical direction are formed in the back pole, and the first sound holes are communicated with the air gap.

9. The MEMS microphone structure of claim 8, wherein: the MEMS microphone structure further comprises a back plate, the back plate is connected with the substrate and the back electrode, a plurality of second sound holes penetrating through the back plate in the vertical direction are formed in the back plate, and the second sound holes are communicated with the first sound holes.

10. The MEMS microphone structure of claim 9, wherein: the lower surface of backplate is equipped with a plurality of blocks, block the piece and run through in the vertical direction the back of the body utmost point, just the lower surface of blocking the piece is less than the lower surface of back of the body utmost point.

11. A manufacturing method of an MEMS microphone structure is characterized by comprising the following steps:

providing a substrate, and forming a first sacrificial layer on the substrate;

forming a groove and a through groove in the first sacrificial layer, wherein the groove is opened from the upper surface of the first sacrificial layer and extends towards the substrate but does not reach the substrate, and the through groove penetrates through the first sacrificial layer in the vertical direction and encloses a support in the first sacrificial layer;

forming a vibrating diaphragm on the first sacrificial layer, wherein the vibrating diaphragm is filled into the groove and the through groove, and the vibrating diaphragm is bent back and forth in the area where the groove is located to form a folding structure, and the distance between the folding structure and the center of the vibrating diaphragm is smaller than the distance between the support and the center of the vibrating diaphragm;

forming a cavity in the substrate, the cavity penetrating the substrate in a vertical direction;

and removing a part of the first sacrificial layer to enable the diaphragm to be suspended above the cavity, wherein the part of the first sacrificial layer serving as the support is not removed.

12. The method of fabricating a MEMS microphone structure according to claim 11, wherein: the lateral wall and the bottom surface of recess are the right angle, beta structure is right angle bending.

13. The method of fabricating a MEMS microphone structure according to claim 11, wherein: 2-10 grooves are formed in the horizontal direction from inside to outside.

14. The method of fabricating a MEMS microphone structure according to claim 11, wherein: the groove may comprise a continuous annular groove or an interrupted annular groove.

15. The method of fabricating a MEMS microphone structure according to claim 14, wherein: the annular groove comprises a circular ring groove or a polygonal annular groove.

16. The method of fabricating a MEMS microphone structure according to claim 11, wherein: the method also comprises the step of forming a gas release hole in the vibrating diaphragm, wherein the vertical projection of the gas release hole on the substrate is positioned outside the cavity.

17. The method of fabricating a MEMS microphone structure as defined by claim 11 further comprising the steps of:

forming a second sacrificial layer, wherein the second sacrificial layer is positioned on the first sacrificial layer and covers the diaphragm;

forming a back electrode on the second sacrificial layer, and forming a plurality of first sound holes penetrating through the back electrode in the vertical direction;

forming a back plate, wherein the back plate is positioned on the substrate and covers the first sacrificial layer, the second sacrificial layer and the back electrode;

forming a second sound hole in the back plate, wherein the second sound hole penetrates through the back plate in the vertical direction and is communicated with the first sound hole;

and removing the second sacrificial layer to obtain an air gap between the back electrode and the diaphragm.

18. The method of fabricating a MEMS microphone structure as defined by claim 17 further comprising the steps of:

forming a plurality of barrier grooves in the second sacrificial layer;

and a plurality of blocking block through grooves penetrating through the back pole in the vertical direction are formed, the blocking block through grooves are opposite to the blocking block grooves in the vertical direction, and the back plate is filled into the blocking block through grooves and the blocking block grooves to form the blocking blocks.

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