A microphone and a method of manufacturing the same

Abstract

The application discloses a microphone and a preparation method thereof, and relates to the technical field of electroacoustic devices. The microphone comprises a circuit board and a shell, the circuit board and the shell are buckled to form a mounting space, a sound hole is formed in the circuit board, a support structure and a MEMS chip are arranged in the mounting space, the support structure has a breathable area, the MEMS chip receives external sound signals through an air flow channel formed by the sound hole and the breathable area, the support structure comprises a support layer, a grid layer and a silicon supporting layer which are sequentially arranged on the circuit board, the MEMS chip is arranged on the grid layer through the silicon supporting layer, a part of the support layer located in the breathable area has a hollow structure, a part of the grid layer located in the breathable area is provided with a plurality of air holes, and a part of the silicon supporting layer located in the breathable area is provided with a through hole; and the support layer is prepared from an organic photosensitive material. The microphone and the preparation method thereof can simplify the structure and the manufacturing process of the microphone, improve the consistency of the microphone manufacturing, and improve the signal-to-noise ratio of the microphone.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electro-acoustic devices, in particular to a microphone and a manufacturing method thereof. BACKGROUND

[0002] In a MEMS (Micro-Electro-Mechanical System) microphone, a diaphragm and a back plate are very important components, and the diaphragm and the back plate together form a capacitor structure to achieve sound-to-electricity conversion. Generally, a MEMS microphone device has an acoustic hole to allow sound pressure to enter the MEMS microphone and interact with the diaphragm thereof. In order to prevent liquid, dust or particles from entering the interior of the microphone along with the air, some solutions in the prior art cover a mesh filter at the position of the acoustic hole on the PCB to isolate the liquid and dust and protect the internal structure. However, the filter arranged on the outer side of the PCB is easily damaged by the environment, and the filter arranged on the inner side of the PCB is complex in process and poor in consistency of the same batch or different batches of products. In addition, some solutions integrate the filter structure inside the MEMS microphone structure, but the size of the filter arranged in this way is difficult to increase due to the limitation of the size of the MEMS microphone, which is not conducive to improving the signal-to-noise ratio of the microphone. SUMMARY

[0003] The purpose of the present application is to provide a microphone and a manufacturing method thereof, which can simplify the structure and manufacturing process of the microphone, improve the consistency of the microphone manufacturing, and improve the signal-to-noise ratio of the microphone.

[0004] Embodiments of the present application are implemented as follows:

[0005] In a first aspect, the present application provides a microphone, which comprises a circuit board and a shell, the circuit board and the shell are clamped to form a mounting space, the circuit board is provided with an acoustic hole, a support structure and a MEMS chip are arranged in the mounting space, the support structure has a breathable area, the MEMS chip receives external sound signals through an air flow channel formed by the acoustic hole and the breathable area, the support structure comprises a support layer, a grid layer and a silicon support layer arranged on the circuit board in sequence, the MEMS chip is arranged on the grid layer through the silicon support layer, a part of the support layer located in the breathable area has a hollow structure, a part of the grid layer located in the breathable area is provided with a plurality of air permeable holes, and a part of the silicon support layer located in the breathable area is provided with a through hole.

[0006] As an implementable manner, the material of the grid layer is silicon or silicon nitride.

[0007] As an implementable manner, the through hole comprises a stepped hole formed by a first through hole and a second through hole, the second through hole is located in a layer of the silicon support layer close to the grid layer, and the aperture of the first through hole is smaller than the aperture of the second through hole.

[0008] As an implementable manner, an oxide layer is further arranged between the grid layer and the silicon supporting layer, and an opening is arranged on the oxide layer and communicates with the second through hole.

[0009] As an implementable manner, the microphone further comprises an ASIC chip, the ASIC chip is arranged on the silicon supporting layer in parallel with the MEMS chip, and the projection of the ASIC chip does not overlap with the projection of the air permeable region.

[0010] As an implementable manner, the surface of the grid layer in the air permeable region is coated with a hydrophobic material, and the hydrophobic angle of the grid layer after being coated with the hydrophobic material is greater than 105°.

[0011] As an implementable manner, the material of the supporting layer is photosensitive polyimide, epoxy-based negative photoresist, or dry film.

[0012] As an implementable manner, the ratio of the total opening area of the plurality of air permeable holes to the area of the air permeable region is greater than or equal to 0.5.

[0013] The second aspect of the embodiment of the present application provides a preparation method of a microphone, comprising: providing a silicon substrate with a selected crystal direction, forming a grid layer of a silicon-based material on the silicon substrate; etching the grid layer to form a plurality of holes in an air permeable region, the bottom wall of the plurality of holes being located in the silicon substrate, wherein the part of the plurality of holes located in the grid layer is a subsequent air permeable hole, and the part located in the silicon substrate is a to-be-etched hole; forming a supporting layer on the grid layer, and patterning the supporting layer to form a hollow structure in the air permeable region, wherein the supporting layer is prepared by using an organic photosensitive organic material; forming a temporary bonding structure on the supporting layer, and thinning the silicon substrate from the bottom surface of the silicon substrate to form a silicon supporting layer; etching from the bottom surface of the silicon supporting layer to form a first through hole, the first through hole communicating with part of the to-be-etched holes; releasing the hole wall of the plurality of to-be-etched holes by anisotropic etching from the first through hole to make the plurality of to-be-etched holes communicate to form a second through hole, the first through hole and the second through hole forming a stepped hole; removing the temporary bonding structure to form a supporting structure; and encapsulating the supporting structure and the MEMS chip in a mounting space formed by the buckling of a circuit board and a shell, wherein the MEMS chip is arranged on the grid layer of the supporting structure through the silicon supporting layer, the circuit board is provided with a sound hole, and the MEMS chip receives external sound signals through the sound hole and the air flow channel formed by the air permeable region.

[0014] As an implementable manner, the silicon substrate with a selected crystal direction is a <111> crystal direction silicon wafer.

[0015] As an implementable manner, after the temporary bonding structure is removed and the supporting structure is formed, the preparation method of the microphone further comprises: coating a hydrophobic material on at least one side of the supporting structure, and the hydrophobic angle of the grid layer after being coated with the hydrophobic material is greater than 105°.

[0016] As an implementable mode, before the grid layer is formed on the silicon substrate, the microphone manufacturing method further comprises forming an oxidation layer on the silicon substrate, and the oxidation layer is used as an etching protection layer of the grid layer in the process of releasing the hole walls of the plurality of to-be-etched holes by the first via hole by anisotropic etching to make the plurality of to-be-etched holes communicate to form the second via hole.

[0017] As an implementable mode, the material of the grid layer is silicon or silicon nitride.

[0018] As an implementable mode, the material of the support layer is photosensitive polyimide, epoxy-based negative photoresist, or dry film.

[0019] The beneficial effects of the embodiments of the present application include:

[0020] The microphone provided by the embodiments of the present application comprises a circuit board and a shell, the circuit board and the shell are buckled to form a mounting space, the circuit board is provided with a sound hole, a support structure and a MEMS chip are arranged in the mounting space, the support structure has a breathable area, the MEMS chip receives external sound signals through an air flow channel formed by the sound hole and the breathable area; the support structure comprises a support layer, a grid layer and a silicon supporting layer which are arranged on the circuit board in sequence, the MEMS chip is arranged on the grid layer through the silicon supporting layer, so that the support structure is located outside the MEMS chip, and thus the area of the breathable area in the support structure can be increased according to actual conditions, that is, the effective area of the support structure is increased, so that the signal-to-noise ratio of the microphone is improved, part of the support layer located in the breathable area has a hollow structure, part of the grid layer located in the breathable area is provided with a plurality of breathable holes, and part of the silicon supporting layer located in the breathable area is provided with a through hole, the grid layer is used to prevent external water, dust and the like from entering the inside of the microphone, so that the dustproof and waterproof performance of the microphone is improved. The support layer is prepared by using an organic photosensitive material, and the fixing of the grid layer can be realized in the curing process of the organic photosensitive material, so that the structure of the microphone is simplified.

[0021] The manufacturing method of the microphone provided by the embodiments of the present application forms the support structure by using the MEMS process, and the process steps and material properties of the MEMS process are highly controllable, so that the consistency of the support structure of the present application is high. In addition, the organic material with photosensitive performance is used in the present application, and the fixing between the layers can be realized in the preparation process, so that the structure and process steps of the microphone are simplified. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below, and it should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 A structural schematic diagram of a microphone provided for an embodiment of the present application;

[0024] Figure 2 A structural schematic diagram of a microphone provided for an embodiment of the present application;

[0025] Figure 3 A structural schematic diagram of a microphone provided for an embodiment of the present application;

[0026] Figure 4 A flow chart of a preparation method of a microphone provided for an embodiment of the present application;

[0027] Figure 5 A state diagram of a preparation method of a microphone provided for an embodiment of the present application;

[0028] Figure 6 A state diagram of a preparation method of a microphone provided for an embodiment of the present application;

[0029] Figure 7 A state diagram of a preparation method of a microphone provided for an embodiment of the present application;

[0030] Figure 8 A state diagram of a preparation method of a microphone provided for an embodiment of the present application;

[0031] Figure 9 A state diagram of a preparation method of a microphone provided for an embodiment of the present application;

[0032] Figure 10 A state diagram of a preparation method of a microphone provided for an embodiment of the present application;

[0033] Figure 11 A state diagram of a preparation method of a microphone provided for an embodiment of the present application.

[0034] Icon: 100-microphone; 111-circuit board; 112-housing; 113-sound hole; 120-supporting structure; 121-supporting layer; 122-mesh layer; 123-silicon supporting layer; 124-vent hole; 125-vent area; 130-MEMS chip; 160-oxide layer; 170-ASIC chip; 210-silicon substrate; 220-temporary bonding structure; 221-temporary bonding layer; 222-temporary bonding glue; 231-first through hole; 232-second through hole; 233-dicing film. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Similar reference numerals and letters in the following drawings represent similar items, and once an item is defined in one drawing, it does not need to be further defined in other drawings.

[0036] The terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed during use, and are merely for the convenience of describing the present application and simplifying the description, and cannot be understood as a limitation on the present application. The terms "first", "second", and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0037] The microphone 100 provided in the embodiments of the present application comprises a circuit board 111 and a shell 112, the circuit board 111 and the shell 112 are buckled to form a mounting space, the circuit board 111 is provided with a sound hole 113, a support structure 120 and a MEMS chip 130 are arranged in the mounting space, the support structure 120 has a breathable area 125, the MEMS chip 130 receives external sound signals through an air flow channel formed by the sound hole 113 and the breathable area 125, the support structure 120 comprises a support layer 121, a mesh layer 122 and a silicon supporting layer 123 arranged on the circuit board 111 in sequence, the MEMS chip 130 is arranged on the mesh layer 122 through the silicon supporting layer 123, a part of the support layer 121 located in the breathable area 125 has a hollow structure, a part of the mesh layer 122 located in the breathable area 125 is provided with a plurality of air holes 124, and a part of the silicon supporting layer 123 located in the breathable area 125 is provided with a through hole; the support layer 121 is prepared from an organic photosensitive material, and the mesh layer 122 is formed from a silicon-based material.

[0038] The microphone 100 provided in the embodiments of the present application works as follows: sound waves enter the microphone 100 through the sound hole 113 on the circuit board 111, and reach the MEMS chip 130 along the breathable area 125 of the support structure 120, the MEMS chip perceives the sound waves and converts the sound waves into electrical signals to realize the perception of the sound waves.

[0039] In the microphone 100 provided in the embodiments of the present application, the mesh layer 122 serves as a waterproof and dustproof component, which prevents sundries in the air from entering the microphone 100, so that the microphone 100 provided in the embodiments of the present application has the functions of waterproofing and dustproofing.

[0040] The organic photosensitive material has the characteristic of being fixedly connected during the curing process, so that the support layer 121 is fixedly connected to the grid layer 122, thereby avoiding the use of a glue layer to paste the grid layer 122 in the prior art, and simplifying the structure of the microphone 100.

[0041] It can be understood that the microphone 100 needs to integrate the MEMS chip 130 and the ASIC chip 170, and the MEMS chip 130 is connected to the ASIC chip 170. The MEMS chip 130 includes a diaphragm and a back plate, which functions to convert sound pressure fluctuations (sound vibrations) into a changing capacitance signal (an analog electrical signal). The ASIC chip 170 is used to obtain this extremely weak analog signal and perform amplification and filtering processing thereon. In some embodiments, the ASIC chip 170 can be disposed on the grid layer 122 at the same time as the MEMS chip 130, so that the wire bonding height of the MEMS chip 130 and the ASIC chip 170 can be reduced, as shown in FIG. 1B. Figure 2 It should be noted that the projection of the ASIC chip 170 on the circuit board 111 does not overlap with the projection of the air-permeable area 125 on the circuit board 111, that is, the support structure 120 below the ASIC chip 170 does not have any hollow structure, so as to improve the support strength of the support structure 120 and avoid the collapse of the support structure 120 due to the pressure generated when the ASIC chip 170 is mounted on the support structure 120.

[0042] In other embodiments, the ASIC chip 170 can also be placed on the circuit board 111 alone, as shown in FIG. 1C, so as to reduce the pressure of the support structure 120. Figure 1

[0043] ​The microphone 100 provided by the embodiment of the present application comprises a circuit board 111 and a shell 112, the circuit board 111 and the shell 112 are buckled to form a mounting space, the circuit board 111 is provided with a sound hole 113, a support structure 120 and a MEMS chip 130 are arranged in the mounting space, the support structure 120 has a breathable area 125, the MEMS chip 130 receives the sound signal of the outside through the airflow channel formed by the sound hole 113 and the breathable area 125; the support structure 120 comprises a support layer 121, a grid layer 122 and a silicon supporting layer 123 arranged on the circuit board 111 in sequence, the MEMS chip 130 is arranged on the grid layer 122 through the silicon supporting layer 123, so that the support structure 120 is located outside the MEMS chip 130, thereby the area of the breathable area 125 in the support structure 120 can be increased according to the actual situation, that is, the effective area of the support structure 120 is increased, so that the signal-to-noise ratio of the microphone 100 is improved, the part of the support layer 121 located in the breathable area 125 has a hollow structure, the part of the grid layer 122 located in the breathable area 125 is provided with a plurality of air holes 124, and the part of the silicon supporting layer 123 located in the breathable area 125 is provided with a through hole, the grid layer 122 is used for preventing water, dust and the like in the outside from entering the inside of the microphone 100, thereby the waterproof and dustproof performance of the microphone 100 is improved. The support layer 121 is prepared by using an organic photosensitive material, and the fixing of the grid layer 122 can be realized in the curing process of the organic photosensitive material, thereby the structure of the microphone 100 is simplified.

[0044] As an implementable manner, the through hole comprises a stepped hole formed by a first through hole 231 and a second through hole 232, the second through hole 232 is located at a layer of the silicon supporting layer 123 close to the grid layer 122, and the aperture of the first through hole 231 is smaller than the aperture of the second through hole 232.

[0045] In the embodiment of the present application, the through hole is set as a stepped hole, and the large hole is close to one side of the grid layer 122, so that the breathable area 125 has a larger effective area, thereby the acoustic resistance of the support structure is reduced, and the signal-to-noise ratio is improved. Specifically, the acoustic impedance of the breathable area 125 in the grid layer 122 of the embodiment of the present application is less than or equal to 1e 9 (Pa.m 3 / s).

[0046] Specifically, the size of the through hole is as shown in the table. Figure 2 The height H1 of the first through hole 231 is greater than or equal to 10 um, the width D1 of the first through hole 231 is between 0.2 and 0.6 mm, the height H2 of the second through hole 232 is between 10 and 30 um, and the width D2 of the second through hole 232 is greater than the width D1 of the first through hole, so that the width of the silicon supporting layer on the side of the second through hole is greater than or equal to 180 um, so as to ensure that the silicon supporting layer provides stable support for the MEMS chip.

[0047] Optionally, the material of the grid layer 122 is silicon or silicon nitride.

[0048] Optionally, as shown in FIG. 1C, an oxide layer 160 is arranged between the grid layer 122 and the silicon supporting layer 123, and an opening is formed in the oxide layer 160 and communicates with the second through hole 232. Figure 3

[0049] The oxide layer 160 arranged between the grid layer 122 and the silicon supporting layer 123 can increase the structural strength of the grid layer 122, and can also protect the grid layer 122 as an etching stop layer.

[0050] Optionally, the oxide layer 160 is silicon oxide.

[0051] As an implementable manner, the surface of the grid layer 122 in the air-permeable area 125 is coated with a hydrophobic material, and the hydrophobic angle of the grid layer after being coated with the hydrophobic material is greater than 105°.

[0052] When water in the environment enters the inside of the microphone 100 along with sound waves, the hydrophobic material can repel water molecules that come into contact with the hydrophobic material, so that water can be prevented from entering the inside of the microphone 100 and the components in the inside of the microphone 100 can be protected. Optionally, the hydrophobic angle of the grid layer after being coated with the hydrophobic material is greater than 105°, so that the grid layer has a good waterproof effect.

[0053] Optionally, the material of the supporting layer 121 is photosensitive polyimide, epoxy-based negative photoresist, or dry film.

[0054] The material of the supporting layer 121 is photosensitive polyimide, epoxy-based negative photoresist, or dry film. These materials are sensitive to light, and the desired pattern can be obtained by exposure and development using a mask, so that one-step microfabrication is realized, and thus the process can be simplified.

[0055] The above-mentioned materials are fixedly connected to the layer structure in contact during the curing process. In the embodiment of the present application, the supporting layer 121 is fixedly connected to the grid layer 122 during the curing process, so that the grid layer 122 is bonded to the supporting layer 121 by using a bonding layer in the prior art, and the structure of the microphone 100 is simplified.

[0056] As an implementable manner, the ratio of the total opening area of the plurality of air-permeable holes 124 to the area of the air-permeable area 125 is greater than or equal to 0.5.

[0057] ​According to the foregoing, the airflow enters the microphone 100 through the plurality of air holes 124, wherein the opening ratio of the air holes 124 (that is, the ratio of the total opening area of the plurality of air holes 124 to the area of the air-permeable region 125) is greater than or equal to 0.5, so that on the limited area of the air-permeable region 125, the mechanical thermal noise caused by the opening flow resistance is reduced, and the signal-to-noise ratio is improved. Those skilled in the art should know that the air-permeable region 125 of the grid layer 122 also needs a certain strength, therefore, the opening ratio cannot be set too large, and the specific setting manner can be limited by those skilled in the art according to the actual situation.

[0058] Wherein, the specific shape of the air-permeable region 125 and the air hole 124 of the grid layer 122 is not limited in the embodiment of the application, for example, the air-permeable region 125 can be circular or square. The air hole 124 is set to be circular, wherein the distance between two air holes 124 is between 1-2 microns, and the diameter of the air hole 124 is less than or equal to 3 μm.

[0059] The second aspect of the embodiment of the application provides a preparation method of the microphone 100, as shown in Figure 4 The preparation method comprises the following steps:

[0060] S110: as shown in Figure 5 The silicon substrate 210 is provided, and the grid layer 122 of silicon-based material is formed on the silicon substrate 210.

[0061] Wherein, the material of the grid layer 122 can be silicon nitride or silicon. The specific forming process of the grid layer 122 is not limited in the embodiment of the application, for example, the low-pressure chemical vapor deposition method can be used, because the silicon nitride layer prepared by the low-pressure chemical vapor deposition method has good density, so that the grid layer 122 has good strength.

[0062] Specifically, the thickness of the grid layer 122 is set to be between 1-5 μm.

[0063] S120: as shown in Figure 5 The grid layer 122 is etched to form a plurality of holes in the air-permeable region 125, and the bottom wall of the plurality of holes is located in the silicon substrate 210, wherein the part of the plurality of holes located in the grid layer 122 is formed subsequently The air hole 124, and the part located in the silicon substrate 210 is the to-be-etched hole.

[0064] Specifically, the photoresist is coated on the upper surface of the grid layer 122, then the mask is used to expose and develop part of the photoresist, so that the photoresist forms an opening, and then the grid layer 122 is etched by using the opening.

[0065] When the grid layer 122 is made of silicon nitride, since it is different from the material of the silicon substrate 210, the etching to form the plurality of holes can be performed in two times, the first time to realize the patterning and etching of the silicon nitride, and the second time to realize the patterning and etching of the silicon material.

[0066] Since each of the plurality of holes extends from the surface of the grid layer 122 into the silicon substrate 210, the air hole 124 and the to-be-etched hole are in one-to-one correspondence and communication, so that the first etching and the second etching can use the same mask. After the first etching is completed, the second etching is directly performed using the existing opening.

[0067] S130: As shown in Figure 6 , a support layer 121 is formed on the grid layer 122, and the support layer is patterned to form a hollow structure in the air-permeable region 125, wherein the support layer 121 is made of an organic photosensitive material.

[0068] Specifically, the organic photosensitive material is laid on the grid layer 122, and then an opening is formed by photolithography using a mask, and then the organic photosensitive material is cured, and in the curing process, the support layer 121 is fixedly connected with the grid layer 122.

[0069] The support layer 121 can be made of photosensitive polyimide, epoxy-based negative photoresist, or dry film. The curing temperature of the photosensitive polyimide is between 200-400°C.

[0070] The above-mentioned materials are sensitive to light, and the desired pattern can be obtained by exposure and development using a mask, realizing one-step microfabrication, so that the preparation process can be simplified, and the support layer 121 and the grid layer 122 can be fixedly connected in the curing process, without the need to form an adhesive layer thereon, so that the preparation method of the microphone 100 and the structure of the microphone 100 can be further simplified.

[0071] The part of the support layer 121 in the air-permeable region 125 has a hollow structure, so that the active part of the support layer 121 is a side wall, and the minimum width (such as W1 in Figure 2 ) of the side wall should be greater than 180μm to ensure the support strength of the support layer 121.

[0072] S140: As shown in Figure 7 and Figure 8 , a temporary bonding structure 220 is formed on the support layer 121, and the silicon substrate 210 is thinned from the bottom surface of the silicon substrate 210 to form a silicon supporting layer 123.

[0073] In order to ensure the strength of the silicon substrate 210 in the foregoing step, a thicker silicon substrate 210 is used, which makes the microphone 100 have a larger volume after subsequent packaging, and does not meet the demand for small size of the microphone. Therefore, after the support layer is arranged, the silicon substrate 210 is thinned from the bottom surface of the silicon substrate 210.

[0074] Specifically, the silicon substrate 210 is thinned by using the temporary bonding structure 220 as a support. In actual application, when the temporary bonding layer 221 is of adhesive material, the temporary bonding layer 221 can be directly bonded on the support layer as the temporary bonding structure 220; when the temporary bonding layer 221 does not have adhesion, the temporary bonding layer 221 can be bonded on the support layer by using a temporary bonding glue 222 as shown in the figure, and the temporary bonding layer 221 and the temporary bonding glue 222 together serve as the temporary bonding structure 220. Figure 7

[0075] More specifically, the temporary bonding layer 221 can be temporary bonding glass.

[0076] S150: As shown in the figure, a first through hole 231 is formed by etching the bottom surface of the silicon support layer 123, and the first through hole 231 is in communication with part of the to-be-etched holes; Figure 9

[0077] The specific etching method is the same as the foregoing, and will not be described here.

[0078] The first through hole 231 can be in communication with part of the to-be-etched holes, and in actual application, the first through hole 231 can be in communication with the multiple to-be-etched holes located at the center, so that when the second through hole 232 is formed by connecting the multiple to-be-etched holes in subsequent steps, the second through hole 232 is coaxial with the first through hole 231.

[0079] S160: As shown in the figure, the hole walls of the multiple to-be-etched holes are released by anisotropic etching from the first through hole 231, so that the multiple to-be-etched holes are connected to form a second through hole 232, and the first through hole 231 and the second through hole 232 form a stepped hole; Figure 10

[0080] Those skilled in the art can know that anisotropic etching refers to the selectivity of a chemical solution to different crystal faces of a single crystal material, and in the embodiment of the application, the chemical solution is used to etch the side walls of the to-be-etched holes. Specifically, the silicon substrate 210 is of <111> silicon, and after the etching solution enters from the first through hole 231, it will only etch along the horizontal direction, so that the side walls of the to-be-etched holes are etched, and the multiple to-be-etched holes are connected. Figure 9

[0081] The specific size and beneficial effects of the stepped hole have been described in detail in the embodiment of the microphone 100, and will not be described here.

[0082] ​​​​The etching solution can be potassium hydroxide, tetramethylammonium hydroxide or an ethylenediamine-o-phenanthroline-water mixed solution.

[0083] S170: as shown in the figure, the temporary bonding structure 220 is removed to form the support structure 120; Figure 10

[0084] The total thickness (H in the figure) of the support structure 120 is less than 180 μm. Figure 2

[0085] The support structure 120 is formed by using the MEMS process. The process steps and material properties of the MEMS process are highly controllable, so that the consistency of the support structure 120 is high.

[0086] S180: as shown in the figures, the support structure 120 and the MEMS chip 130 are packaged in the mounting space formed by the buckling of the circuit board 111 and the shell 112, wherein the MEMS chip 130 is arranged on the grid layer 122 of the support structure 120 through the silicon supporting layer 123, the sound hole 113 is formed on the circuit board 111, and the MEMS chip 130 receives the external sound signal through the air flow channel formed by the sound hole 113 and the air permeable area 125. Figure 1 Figure 2

[0087] The packaging process is the same as that in the prior art, and will not be described here. As long as the packaging becomes the structure of the microphone 100 in the present application, as shown in the figures. Figure 1 Figure 2

[0088] In actual application, a plurality of support structures 120 described above are formed on a wafer. Before packaging, the support structure 120 needs to be cut from the wafer. Specifically, as shown in the figure, a dicing film 233 is attached to one side of the wafer, and dicing is performed so that the support structure 120 becomes an independent structure. Figure 11

[0089] Optionally, after the temporary bonding structure 220 is removed to form the support structure 120, the method for manufacturing the microphone 100 further comprises: applying a hydrophobic material to at least one side of the support structure 120, and the hydrophobic angle of the grid layer after the hydrophobic material is applied is greater than 105°.

[0090] After the temporary bonding layer 221 is removed, the two sides of the protection structure respectively have a stepped hole and a support layer 121 hollow structure, and the hydrophobic material can be applied to the air permeable area 125 of the grid layer 122 through the stepped hole and the hollow structure, respectively. The hydrophobic material falls and adheres to the surface of the air permeable area 125 of the grid layer 122.

[0091] ​​​​​​​It can be understood that the hydrophobic material can be arranged on one side close to the stepped hole, on one side close to the hollow structure, or on both sides close to the stepped hole and the hollow structure.

[0092] The arrangement of the hydrophobic material can improve the waterproof effect of the microphone 100.

[0093] As an implementable manner, before the grid layer 122 is formed on the silicon substrate 210, the microphone 100 manufacturing method further includes: forming an oxidation layer 160 on the silicon substrate 210; and in the process of releasing the walls of the plurality of to-be-etched holes by anisotropic etching by using the first through hole 231 to make the plurality of to-be-etched holes communicate to form the second through hole 232, the oxidation layer 160 is used as an etching protection layer of the grid layer 122.

[0094] Specifically, the method for forming the oxidation layer 160 is not limited in the embodiments of the present application, for example, the silicon material on the surface of the silicon substrate 210 can be oxidized to form a silicon dioxide layer as the oxidation layer 160 by thermal oxidation; or the silicon dioxide material can be deposited by chemical vapor deposition or atomic layer deposition.

[0095] When the oxidation layer 160 is formed on the silicon substrate 210, and then the grid layer 122 is formed on the oxidation layer 160, in the etching in step S120, the plurality of holes penetrate the oxidation layer 160 and extend into the silicon substrate 210.

[0096] In addition, the oxidation layer 160 can also be used as an etching stop layer in the etching in step S160, so as to protect the silicon nitride layer of the air-permeable region 125 of the grid layer 122.

[0097] The above only describes optional embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0098] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present application.

Claims

1. A method of manufacturing a microphone, characterized by, The method comprises the following steps: providing a silicon substrate with selected crystal orientation, forming a grid layer of silicon-based material on the silicon substrate; etching the grid layer to form a plurality of holes in the air-permeable region, the bottom walls of the plurality of holes being located in the silicon substrate, wherein the plurality of holes located in the grid layer are to be formed into air-permeable holes, and the part located in the silicon substrate is to be etched; forming a support layer on the grid layer, and patterning the support layer to form a hollow structure in the air-permeable region, wherein the support layer is made of organic photosensitive material; forming a temporary bonding structure on the support layer, and thinning the silicon substrate from the bottom surface of the silicon substrate to form a silicon supporting layer; etching a first through hole from the bottom surface of the silicon supporting layer, the first through hole being in communication with part of the to-be-etched holes; releasing the hole walls of the plurality of to-be-etched holes by anisotropic etching from the first through hole to form a second through hole in communication with the plurality of to-be-etched holes, and the first through hole and the second through hole form a stepped hole; removing the temporary bonding structure to form a support structure; enclosing the support structure and a MEMS chip in a mounting space formed by the lamination of a circuit board and a shell, wherein the MEMS chip is arranged on the grid layer of the support structure through the silicon supporting layer, the circuit board is provided with a sound hole, and the MEMS chip receives external sound signals through the sound hole and the airflow channel formed by the air-permeable region.

2. The method of claim 1, wherein the method further comprises: The silicon substrate with selected crystal orientation is a <111> crystal silicon wafer.

3. The method of claim 1, wherein the method further comprises: After the step of removing the temporary bonding structure to form a support structure, the method further comprises the following steps: applying a hydrophobic material to at least one side of the support structure, and the hydrophobic angle of the grid layer after the application of the hydrophobic material is greater than 105°.

4. The method of claim 1, wherein the method further comprises: Before the step of forming a grid layer on the silicon substrate, the method further comprises the following steps: forming an oxide layer on the silicon substrate; and in the process of releasing the hole walls of the plurality of to-be-etched holes by anisotropic etching from the first through hole to form a second through hole in communication with the plurality of to-be-etched holes, the oxide layer serves as an etching protective layer for the grid layer.

5. The method of claim 1, wherein the method further comprises: The material of the grid layer is silicon or silicon nitride.

6. The method of claim 1, wherein the method further comprises: The material of the support layer is photosensitive polyimide, epoxy-based negative photoresist, or dry film.

7. A microphone, characterized by The method comprises the following steps: providing a silicon substrate with selected crystal orientation, forming a grid layer of silicon-based material on the silicon substrate; etching the grid layer to form a plurality of holes in the air-permeable region, the bottom walls of the plurality of holes being located in the silicon substrate, wherein the plurality of holes located in the grid layer are to be formed into air-permeable holes, and the part located in the silicon substrate is to be etched; forming a support layer on the grid layer, and patterning the support layer to form a hollow structure in the air-permeable region, wherein the support layer is made of organic photosensitive material; forming a temporary bonding structure on the support layer, and thinning the silicon substrate from the bottom surface of the silicon substrate to form a silicon supporting layer; etching a first through hole from the bottom surface of the silicon supporting layer, the first through hole being in communication with part of the to-be-etched holes; releasing the hole walls of the plurality of to-be-etched holes by anisotropic etching from the first through hole to form a second through hole in communication with the plurality of to-be-etched holes, and the first through hole and the second through hole form a stepped hole; removing the temporary bonding structure to form a support structure; enclosing the support structure and a MEMS chip in a mounting space formed by the lamination of a circuit board and a shell, wherein the MEMS chip is arranged on the grid layer of the support structure through the silicon supporting layer, the circuit board is provided with a sound hole, and the MEMS chip receives external sound signals through the sound hole and the airflow channel formed by the air-permeable region. The silicon substrate with selected crystal orientation is a <111> crystal silicon wafer. After the step of removing the temporary bonding structure to form a support structure, the method further comprises the following steps: applying a hydrophobic material to at least one side of the support structure, and the hydrophobic angle of the grid layer after the application of the hydrophobic material is greater than 105°. Before the step of forming a grid layer on the silicon substrate, the method further comprises the following steps: forming an oxide layer on the silicon substrate; and in the process of releasing the hole walls of the plurality of to-be-etched holes by anisotropic etching from the first through hole to form a second through hole in communication with the plurality of to-be-etched holes, the oxide layer serves as an etching protective layer for the grid layer. The material of the grid layer is silicon or silicon nitride. The material of the support layer is photosensitive polyimide, epoxy-based negative photoresist, or dry film. The method comprises the following steps: providing a silicon substrate with selected crystal orientation, forming a grid layer of silicon-based material on the silicon substrate; The through hole comprises a stepped hole formed by a first through hole and a second through hole, the second through hole is located on a side of the silicon supporting layer close to the mesh layer, and a hole diameter of the first through hole is smaller than a hole diameter of the second through hole.

8. The microphone of claim 7, wherein, The mesh layer is made of silicon or silicon nitride.

9. The microphone of claim 7, wherein, An oxidation layer is further arranged between the mesh layer and the silicon supporting layer, and the oxidation layer is provided with an opening in communication with the second through hole.

10. The microphone of claim 7, wherein, An ASIC chip is further included, the ASIC chip is arranged on the silicon supporting layer in parallel with the MEMS chip, and a projection of the ASIC chip does not overlap with a projection of the air-permeable area.

11. The microphone of claim 7, wherein, A surface of the mesh layer located in the air-permeable area is coated with a hydrophobic material, and a hydrophobic angle of the mesh layer after being coated with the hydrophobic material is greater than 105 degrees.

12. The microphone of claim 7, wherein, The supporting layer is made of photosensitive polyimide, epoxy-based negative photoresist, or dry film.

13. The microphone of claim 7, wherein, A ratio of a total open area of the plurality of air-permeable holes to an area of the air-permeable area is greater than or equal to 0.5.

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