CN110677794A

CN110677794A - Microphone packaging structure and forming method thereof

Info

Publication number: CN110677794A
Application number: CN201911016030.0A
Authority: CN
Inventors: 梅嘉欣; 张永强; 唐行明
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2020-01-10

Abstract

The invention relates to a microphone packaging structure and a forming method thereof, wherein the microphone packaging structure comprises: the surface of the substrate is provided with a first concave part; the packaging shell is fixed on the surface of the substrate, and a first cavity is formed between the packaging shell and the substrate; the microphone chip is arranged in the first cavity and comprises a pressure sensing layer and a supporting structure, the supporting structure and the pressure sensing layer form a second cavity, the top of the supporting structure supports the pressure sensing layer, and the bottom of the supporting structure is fixed on the surface of the substrate, so that the second cavity is communicated with the first concave part, and the first concave part is positioned in the projection of the second cavity on the surface of the substrate. The acoustic performance of the microphone chip of the microphone packaging structure is not influenced by the packaging process.

Description

Microphone packaging structure and forming method thereof

Technical Field

The invention relates to the technical field of MEMS, in particular to a microphone packaging structure and a forming method thereof.

Background

In the prior art, in the MEMS microphone packaging structure, the MEMS microphone is usually connected to the substrate by curing through a glue. In the large-scale manufacturing process, due to the non-uniformity of the glue dispensing amount of the machine, when the MEMS microphone is pasted on the substrate and is extruded with the glue, the glue is often overflowed to the inner side and the outer side of the side wall of the MEMS microphone, and when the excessive glue part overflows into the cavity of the MEMS microphone, the cavity of the MEMS microphone is usually too small, so that the acoustic performance of the MEMS microphone is influenced, and the failure rate of a product is improved.

The prior art has adopted and changes the inside lateral wall of MEMS microphone cavity into rough surface by smooth etching to this reduces the colloid and spills over the influence to MEMS microphone cavity, but actually this scheme effect is not very ideal, because the cavity of MEMS microphone itself is very little, even if the colloid does not climb up along the lateral wall, still exist in cavity inner space, lead to the cavity volume to diminish, still have great influence to acoustic performance.

Therefore, how to avoid the influence of the packaging process on the acoustic performance of the microphone is a problem to be solved urgently.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a microphone packaging structure to reduce the adverse effect of the packaging process on the acoustic performance of the microphone.

In order to solve the above problem, the present invention provides a microphone package structure, comprising: the surface of the substrate is provided with a first concave part; the packaging shell is fixed on the surface of the substrate, and a first cavity is formed between the packaging shell and the substrate; the microphone chip is arranged in the first cavity and comprises a pressure sensing layer and a supporting structure, the supporting structure and the pressure sensing layer form a second cavity, the top of the supporting structure supports the pressure sensing layer, and the bottom of the supporting structure is fixed on the surface of the substrate, so that the second cavity is communicated with the first concave part, and the first concave part is positioned in the projection of the second cavity on the surface of the substrate.

Optionally, a cross-sectional shape of the first recess along a direction parallel to the substrate is a square, a circle, or a polygon, and/or a cross-sectional shape along a direction perpendicular to the substrate is a trapezoid, a rectangle, an arc, or a polygon.

Optionally, the first recess has a stepped sidewall, and the support structure bottom is fixed to a top stepped surface of the sidewall of the first recess.

Optionally, the method further includes: at least one blocking part is arranged between the top step and the first sunken part, and the bottom of the supporting structure is fixed on the periphery of the blocking part.

Optionally, the blocking portion is a plurality of discrete protrusions arranged around the first recess or the blocking portion is a continuous protrusion arranged around the groove.

Optionally, the continuous raised surrounding area is square, circular or polygonal.

Optionally, the method further includes: the second depressed part is located the base plate surface encircles the first depressed part sets up, the second depressed part degree of depth is less than the first depressed part degree of depth, the bearing structure bottom of microphone chip is fixed in the second depressed part.

Optionally, the method further includes: the special integrated circuit chip is arranged in the first cavity; the application specific integrated circuit chip is connected to the microphone chip; further comprising: and the sound hole is communicated with the first cavity and the outside of the microphone packaging structure.

Optionally, a metal layer is disposed on the inner wall surface of the first recess.

Optionally, the microphone chip and the substrate are fixed by a glue, and the glue on the inner part of the second cavity overflows into the first recess.

In order to solve the above problem, the technical solution of the present invention further provides a method for forming a microphone package structure, including: providing a substrate and a microphone chip, wherein a first concave part is formed on the surface of the substrate, the microphone chip comprises a pressure sensing layer and a supporting structure, a second cavity is formed between the supporting structure and the pressure sensing layer, and the top of the supporting structure supports the pressure sensing layer; fixing the bottom of the supporting structure of the microphone chip on the surface of the substrate, so that the second cavity is communicated with the first concave part, and the first concave part is positioned in the projection of the second cavity on the surface of the substrate; and providing a packaging shell, fixing the packaging shell on the surface of the substrate, and forming a first cavity between the packaging shell and the substrate, so that the first concave part and the microphone chip are positioned in the first cavity.

Optionally, the method for fixing the bottom of the supporting structure of the microphone chip to the surface of the substrate through the colloid includes: coating colloid on the periphery of the first concave part, extruding the bottom of the supporting structure of the microphone chip on the colloid, and curing to fix the microphone chip on the surface of the substrate; after the colloid is extruded, part of the colloid overflows from the inner side of the second cavity into the first concave part.

Optionally, the cross section of the first recess is square, circular arc or polygonal.

Optionally, the first recess has a stepped sidewall, and the bottom of the support structure is fixed to a top stepped surface of the sidewall of the first recess.

Optionally, at least one blocking portion is arranged between the top step and the first concave portion, and the bottom of the supporting structure is fixed to the periphery of the blocking portion.

Optionally, the cross-sectional shape of the first recess along a direction parallel to the substrate is square, circular or polygonal, and/or the cross-sectional shape along a direction perpendicular to the substrate is trapezoid, rectangular, circular arc or polygonal.

Optionally, a second recessed portion is further formed on the surface of the substrate, and is disposed around the first recessed portion, and the depth of the second recessed portion is smaller than that of the first recessed portion; and fixing the bottom of the supporting structure of the microphone chip in the second concave part.

Optionally, the method further includes: and forming a metal layer on the inner wall surface of the first concave part.

The substrate surface of the microphone packaging structure is provided with the first concave part, the microphone chip is fixed above the first concave part, and in the extrusion fixing process of the colloid for fixing the microphone chip, excessive colloid can overflow into the first concave part, so that the colloid is prevented from occupying the volume of the second cavity of the microphone chip, the acoustic performance of the microphone chip is prevented from being influenced by the packaging process, the contact area between the colloid and the substrate can be increased, and the bonding reliability between the microphone chip and the substrate is improved.

Drawings

Fig. 1 is a schematic diagram of a microphone package structure according to an embodiment of the invention;

FIG. 2 is a schematic top view of a substrate according to one embodiment of the present invention;

fig. 3 is a schematic diagram of a microphone package structure according to an embodiment of the invention;

FIG. 4 is a schematic top view of a substrate according to one embodiment of the present invention;

fig. 5 is a schematic diagram of a microphone package structure according to an embodiment of the invention;

FIG. 6 is a schematic top view of a substrate according to one embodiment of the present invention;

fig. 7 is a schematic diagram of a microphone package structure according to an embodiment of the invention;

FIG. 8 is a schematic top view of a substrate according to one embodiment of the present invention;

fig. 9 is a flowchart illustrating a method for forming a microphone package structure according to an embodiment of the invention.

Detailed Description

The following describes a microphone package structure and a method for forming the same in detail with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a microphone package structure according to an embodiment of the invention.

The microphone packaging structure includes: a substrate 100, wherein a first concave part 101 is formed on the surface of the substrate 100; the package housing 110 is fixed on the surface of the substrate 100, a first cavity 112 is formed between the package housing 110 and the substrate 100, and the first recess 101 is located in the first cavity 112; the microphone chip 120 is disposed in the first cavity 112, the microphone chip 120 includes a pressure sensing layer 122 and a supporting structure 121, a second cavity 123 is formed between the supporting structure 121 and the pressure sensing layer 122, the top of the supporting structure 121 supports the pressure sensing layer 122, and the bottom of the supporting structure 121 is fixed to the surface of the substrate 100, so that the second cavity 123 is communicated with the first recess 101, and the first recess 101 is located in a projection of the second cavity 123 on the surface of the substrate 100.

The microphone chip 120 may be a MEMS chip.

The microphone package structure further includes an asic chip 130 disposed in the first cavity 112; the asic chip 130 is connected to the microphone chip 120. In this embodiment, the asic chip 130 is fixed to the surface of the substrate 100. In other embodiments, the integrated circuit chip 130 may be embedded or integrated inside the substrate 100. The asic chip 130 is used for acquiring the sensing signal output by the microphone chip 120 and processing the sensing signal.

The substrate 100 may be made of a conventional substrate material such as RF-4, BT or ceramic substrate. The substrate 100 may have solder pads or electrical connection structures formed thereon for providing electrical connection points. The substrate 100 may be a single-layer or multi-layer circuit board, and the surface of the substrate 100 may be formed with a circuit structure, or an electrical contact, such as a pad; the substrate 100 may further have an electrical connection structure formed therein for connecting electrical contacts on the front and back surfaces of the substrate 100.

The package housing 110 serves as a package casing of the microphone package structure, and is used for protecting internal electronic components, and a first cavity 112 is formed between the package housing and the substrate 100. The packaging shell 110 can be made of metal, is high-temperature resistant, is simple in production process, and can be produced in large scale, and the metal shell packaging shell 110 also has the characteristics of corrosion resistance, electromagnetic shielding effect, high mechanical property and the like, so that the product is protected well. In other embodiments, the package housing 110 may also be made of other hard materials such as plastic, which is not limited herein.

The edge of the package housing 110 is fixed to the front surface of the substrate 100 by welding or gluing, so that a first cavity 112 is formed between the package housing 110 and the substrate 100. In this embodiment, the package housing 110 has a sound hole 111 penetrating through the package housing 110, and preferably, the sound hole 111 is located at the top of the package housing 110. The sound hole 111 communicates the first cavity 112 with the exterior of the microphone package structure. The package housing 110 has at least one sound hole 111 therein. In this embodiment, the package housing 110 has only 1 sound hole 111, and in other embodiments, the package housing 110 may have more than two sound holes. The edge of the package housing 110 is hermetically connected to the substrate 100, so that the first cavity 112 can communicate with the outside only through the sound hole 111, and the gas in the first cavity 112 does not leak at other positions.

In other embodiments, the sound hole 111 may be formed in the substrate 100, penetrating through the substrate 110, and communicating with the first cavity 112.

Referring to fig. 1 and fig. 2, the surface of the substrate 100 has a first recess 101. Fig. 2 is a schematic top view of the substrate 100. In this embodiment, the cross section of the first recess 101 along the direction parallel to the substrate 100 is square. In some embodiments, a cross section of the first recess 101 along a direction parallel to the substrate 100 may also be circular or polygonal, etc. In some embodiments, the cross-sectional shape of the first recess 101 along the direction perpendicular to the substrate 100 is trapezoidal, rectangular, circular, or polygonal. The first concave part 101 only needs to have a bottom lower than the surface of the substrate 100 to accommodate the excessive glue, and a person skilled in the art can reasonably set the shape of the first concave part 101. The size of the first recess 101 is adjusted according to the size of the second cavity 123 of the microphone chip 120.

The microphone chip 120 includes a second cavity 123 as a back cavity. The pressure sensing layer 122 of the microphone chip 120 includes a back plate and a vibrating film layer, which are disposed opposite to each other to form an inductive capacitor. When the pressure inside the first cavity 112 changes, the pressure sensing layer 122 deforms, so that the capacitance changes, and a sensing signal is output.

The second cavity 123 is in communication with the first recess 101, and the cross-sectional dimension of the first recess 101 is smaller than the cross-sectional dimension of the second cavity 123, such that the first recess 101 is completely covered by the second cavity 123. The inner wall of the support structure 121 is positioned close to the edge of the first recess 101 or in alignment with the first recess 101.

The supporting structure 121 of the microphone chip 120 is fixed on the surface of the substrate 100 by the colloid 105. When the microphone chip 120 is fixed, a certain acting force is applied to the microphone chip 120 through equipment, so that the bottom of the supporting structure 121 and the colloid 105 have a larger contact area, and the fixing effect is improved. The colloid is extruded and overflows to two sides of the bottom of the supporting structure 121, a part of the colloid overflows to the outer side of the supporting structure 121 and ascends to a certain height along the outer wall of the microphone chip 120, a part of the colloid overflows to the inner side of the supporting structure 121, excessive colloid overflows to the side wall or the bottom of the first concave part 101 from the edge of the first concave part 101 at the inner side of the microphone chip 120, and the subsequent colloid is cured at a certain temperature and for a certain time, so that the microphone chip 120 is tightly connected with the substrate 100. The colloid overflowing to the microphone chip 120 is cured on the inner wall or the bottom of the groove, the volume of the second cavity 123 of the microphone chip 120 is not affected, the contact area between the colloid 105 and the substrate 100 can be increased, and the reliability of connection between the microphone chip 120 and the substrate 100 is improved.

In other specific embodiments, a metal layer may be further formed on the surface of the first recess 101, and the metal layer plays a role of electromagnetic shielding, so as to improve the capability of the microphone chip 120 against electromagnetic interference. Moreover, when the colloid 105 inside the second cavity 123 overflows into the first recess 101, the colloid can well extend on the surface of the metal layer and spread on the surface of the metal layer, so that the contact surface is improved. The material of the metal layer can be elementary metal or alloy metal material, including at least one of gold, copper, nickel or zinc. The metal layer may be a single layer structure or a composite structure. In one embodiment, the metal layer includes a copper layer, a nickel layer covering a surface of the copper layer, and a gold layer covering the nickel layer. The metal layer with the composite structure can improve the electromagnetic shielding effect of the metal layer and the reliability in the process of curing the colloid at high temperature.

The metal layer at least covers the side wall of the first recess 201, so that the overflowing glue can more easily flow into the first recess 201 along the side wall of the first recess 201. Preferably, the metal layer covers the entire inner wall of the first recess 201, including the side wall and the bottom, so that the glue can be spread on the surface of the metal layer.

Fig. 3 is a schematic view of a microphone package structure according to another embodiment of the invention.

In this embodiment, the first recess 201 on the substrate 100 has a step-shaped sidewall, and the bottom of the supporting structure 121 of the microphone chip 120 is fixed on the top step 2011 surface of the sidewall of the first recess 201.

Referring to fig. 4, fig. 4 is a schematic top view of the substrate 100 according to this embodiment.

In this embodiment, the sidewall of the first recess 201 on the surface of the substrate 100 has one step 2011, and in other embodiments, the sidewall of the first recess 201 may have more than two steps.

The surface area of the top step 2011 of the side wall of the first recess 201 is larger than the bottom area of the support structure 121 of the microphone chip 120, the colloid 105 is coated on the surface of the top step 2011, and the microphone chip 120 is bonded on the substrate 100 through the colloid 105.

The top step 2011 is disposed around the recess of the first recess 201, and the surrounding area may have other shapes such as a square, a circle, or a polygon.

When the microphone chip 120 is fixed, the colloid 105 overflows to the inner side and the outer side of the supporting structure 121. The glue overflowing to the outside of the supporting structure 121 is blocked by the sidewall higher than the surface of the top step 2011, and more glue will climb up along the outer wall of the supporting structure 121, so as to better adhere to the microphone chip 120. The adhesive overflowing to the inner side of the supporting structure 121 may overflow to the inner wall and/or the bottom of the first recess 201, so as to improve the adhesion reliability between the microphone chip 120 and the substrate 100.

Fig. 5 is a schematic view of a microphone package structure according to another embodiment of the invention.

In this embodiment, a second recess 501 is further formed on the surface of the substrate 100 of the microphone package structure, the second recess 501 is located on the surface of the substrate 100 and surrounds the first recess 101, the depth of the second recess 501 is smaller than the depth of the first recess 101, and the bottom of the supporting structure 121 of the microphone chip 120 is fixed in the second recess 501.

The second recess 501 is disposed around the first recess 101, and a convex portion is formed between the first recess 101 and the second recess 501 as a blocking wall 1051.

The bottom of the supporting structure 121 of the microphone chip 120 is adhered to the bottom surface of the second recess 501 through the adhesive 105. The excessive colloid 105 may overflow the side barrier 1051 of the second recess 501 and climb along the barrier 1051. If the adhesive overflows, when the excessive adhesive overflows from the second recess 501 to the first recess 101, the inner and outer sidewalls of the supporting structure 121 of the microphone chip 120 are covered by the sufficient adhesive 105, and the contact area between the adhesive 105 and the substrate 100 is increased, so that the bonding is more secure. The excessive glue that overflows falls into the first concave portion and is firmly bonded with the substrate 100 through subsequent glue curing, and the acoustic performance of the microphone chip 120 is not affected.

Referring to fig. 6, a top view of the substrate 100 according to this embodiment is shown.

The second recess 501 is disposed around the first recess 101, and in this embodiment, the shape of the area surrounded by the second recess 501 is the same as the cross section of the first recess 101, so that the width of the barrier wall 1051 is uniform, the contact area of the colloid 105 and the barrier wall 1051 is the same, and the bonding strength is uniform, thereby improving the uniformity and reliability of the bonding between the microphone chip 120 and the substrate 100.

In other specific embodiments, the surrounding area of the second recess 501 may be circular, polygonal, or other shapes.

Fig. 7 is a schematic view of a microphone package structure according to another embodiment of the invention.

This embodiment is a further improvement of the structure of fig. 3. In this embodiment, at least one blocking portion is disposed between the top step 1021 and the first recess 201, and the bottom of the supporting structure 121 is fixed to the periphery of the blocking portion.

In this embodiment, two blocking portions are formed between the surface of the top step 1021 and the first recess 201, which are a first blocking portion 701 and a second blocking portion 702 located between the first blocking portion 701 and the first recess 201, respectively, and a certain distance is formed between the first blocking portion 701 and the second blocking portion 702.

Referring to fig. 8, a top view of the substrate 100 according to this embodiment is shown.

In this specific embodiment, the first blocking portion 701 and the second blocking portion 702 are disposed in parallel around the first recessed portion 201, and both the first blocking portion 701 and the second blocking portion 702 are continuous protrusions. The surrounding area of the first barrier 701 and the second barrier 702 may be a circle, a square, a polygon, or the like.

In other embodiments, the blocking portion may be a plurality of discrete protrusions disposed around the first recess 201.

In this embodiment, the top and bottom of the second blocking portion 702 closer to the first recess 201 are lower than the first blocking portion 701, which is more favorable for the overflowing glue to flow to the first recess 201.

When the microphone chip 120 is bonded to the colloid 105, the colloid overflowing beyond the first blocking portion 701 flows into the groove between the first blocking portion 701 and the second blocking portion 702, covers the surfaces of the first blocking portion 701 and the second blocking portion 702, and further overflows into the first recess 201 without affecting the acoustic performance of the microphone chip 120. In addition, the contact area between the adhesive 105 and the substrate 100 is increased, and the reliability of the fixed connection between the microphone chip 120 and the substrate 100 can be further improved.

The first barrier 701 and the second barrier 702 are integrated with the substrate 100, and in other specific embodiments, the first barrier 701 and the second barrier 702 are additionally disposed on the surface of the substrate 100.

In the microphone package structure of the above specific embodiment, the substrate surface has the first recess, and the microphone chip is fixed to the top of the first recess, so that the colloid of the microphone chip is fixed in the process of fixing the microphone chip by extrusion, and excessive colloid overflows into the first recess, thereby preventing the colloid from occupying the cavity of the microphone chip, avoiding affecting the acoustic performance of the microphone chip, improving the contact area between the colloid and the substrate, and improving the reliability of the combination between the microphone chip and the substrate.

The invention further provides a forming method of the microphone packaging structure.

Fig. 9 is a flowchart illustrating a process of forming a microphone package structure according to an embodiment of the invention.

In this embodiment, the forming process of the microphone packaging structure includes steps S101 to S103.

Step S101: providing a substrate and a microphone chip, wherein a first concave part is formed on the surface of the substrate, and the microphone chip comprises a second cavity. The microphone chip comprises a pressure sensing layer and a supporting structure, a second cavity is formed between the supporting structure and the pressure sensing layer, and the top of the supporting structure supports the pressure sensing layer.

The first concave part can be formed by etching the substrate, and is easy to prepare in a large scale. In one embodiment, the first recess has a square cross-section in a direction parallel to the substrate. In some embodiments, a cross section of the first recess portion along a direction parallel to the substrate may also be circular or polygonal, etc. In some embodiments, the cross-sectional shape of the first recessed portion along the direction perpendicular to the substrate may be trapezoidal, rectangular, circular, polygonal, or other various shapes.

In other embodiments, the first recess may also have a stepped sidewall. In another specific embodiment, a second recess is further formed on the substrate surface, the second recess is located on the substrate surface and surrounds the first recess, the second recess is smaller than the first recess, and the bottom of the supporting structure of the microphone chip is subsequently fixed in the second recess.

In other specific embodiments, a metal layer may be formed on the inner wall surface of the first recess by deposition, electroplating, or the like. The material of the metal layer can be elementary metal or alloy metal material, including at least one of gold, copper, nickel or zinc. The metal layer may be a single layer structure or a composite structure. In one embodiment, the metal layer includes a copper layer, a nickel layer covering a surface of the copper layer, and a gold layer covering the nickel layer. The metal layer with the composite structure can improve the electromagnetic shielding effect of the metal layer and the reliability in the process of curing the colloid at high temperature.

The metal layer at least covers the side wall of the first recess 201, so that the overflowing glue can more easily flow into the first recess 201 along the side wall of the first recess 201. Preferably, the metal layer covers the entire inner wall of the first recess 201, including the side wall and the bottom, so that the glue can be spread on the surface of the metal layer. The location of the metal layer coverage may be defined by an etching process.

The microphone also comprises an application specific integrated circuit chip which is easy to process and output the sensing signal output by the microphone chip.

Step S102: the bottom of the supporting structure of the microphone chip is fixed on the surface of the substrate through a colloid, so that the second cavity is communicated with the first concave part, and the first concave part is positioned in the projection of the second cavity on the surface of the substrate.

The method for fixing the bottom of the supporting structure of the microphone chip on the surface of the substrate through the colloid comprises the following steps: coating colloid on the periphery of the first concave part, extruding the bottom of the supporting structure of the microphone chip on the colloid, and curing to fix the microphone chip on the surface of the substrate; after the colloid is extruded, part of the colloid overflows into the first concave part. The colloid overflows into the first depressed part, can not block the second cavity of the microphone chip, and can improve the bonding area between the colloid and the substrate, and improve the reliability of the microphone chip fixed on the surface of the substrate.

When the first recess has a stepped sidewall, the support structure bottom is secured to a top step surface of the sidewall of the first recess. In another specific embodiment, at least one blocking portion is arranged between the top step and the first recess, and the bottom of the supporting structure of the microphone chip is fixed on the periphery of the blocking portion. The blocking part is a plurality of discrete protruding parts arranged around the first concave part or the blocking part is a continuous protruding part arranged around the groove. The continuous convex surrounding area is square, circular or polygonal.

Step S103: and providing a packaging shell, fixing the packaging shell on the surface of the substrate, and forming a first cavity between the packaging shell and the substrate, so that the first concave part and the microphone chip are positioned in the first cavity.

The edge of the package housing can be fixed on the surface of the substrate by welding or gluing, and other electronic elements such as a microphone chip and an application specific integrated circuit chip can be covered and protected. The packaging shell can be provided with a sound hole so as to communicate the first cavity and the exterior of the packaging structure. In other specific embodiments, the sound hole may be further formed in the substrate, penetrating the substrate, to communicate the first cavity with the outside.

In the forming method of the microphone packaging structure, the substrate with the first concave part on the surface is adopted, the microphone chip is fixed above the first concave part, when the microphone chip is fixed on the surface of the substrate through the colloid, the colloid overflowing towards the inner side of the microphone chip can overflow into the first concave part, so that the occupation of the space in the inner cavity of the microphone chip is reduced or avoided, the acoustic performance of the microphone chip is not influenced, the bonding area between the colloid and the substrate is increased, and the reliability of the direct fixed connection between the microphone chip and the substrate is improved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A microphone package structure, comprising:

the surface of the substrate is provided with a first concave part;

the packaging shell is fixed on the surface of the substrate, and a first cavity is formed between the packaging shell and the substrate;

the microphone chip is arranged in the first cavity and comprises a pressure sensing layer and a supporting structure, the supporting structure and the pressure sensing layer form a second cavity, the top of the supporting structure supports the pressure sensing layer, and the bottom of the supporting structure is fixed on the surface of the substrate, so that the second cavity is communicated with the first concave part, and the first concave part is positioned in the projection of the second cavity on the surface of the substrate.

2. The microphone package structure of claim 1, wherein a cross-sectional shape of the first recess along a direction parallel to the substrate is a square, a circle, or a polygon, and/or a cross-sectional shape along a direction perpendicular to the substrate is a trapezoid, a rectangle, an arc, or a polygon.

3. The microphone package structure of claim 1, wherein the first recess has a stepped sidewall, and the support structure bottom is fixed to a top stepped surface of the sidewall of the first recess.

4. The microphone package structure of claim 3, further comprising: at least one blocking part is arranged between the top step and the first sunken part, and the bottom of the supporting structure is fixed on the periphery of the blocking part.

5. The microphone package structure of claim 4, wherein the blocking portion is a plurality of discrete protrusions disposed around the first recess or the blocking portion is a continuous protrusion disposed around the recess.

6. The microphone package structure of claim 5, wherein the continuous raised surrounding area is square, circular, or polygonal.

7. The microphone package structure of claim 1, further comprising: the second depressed part is located the base plate surface encircles the first depressed part sets up, the second depressed part degree of depth is less than the first depressed part degree of depth, the bearing structure bottom of microphone chip is fixed in the second depressed part.

8. The microphone package structure of claim 1, further comprising: the special integrated circuit chip is arranged in the first cavity; the application specific integrated circuit chip is connected to the microphone chip; further comprising: and the sound hole is communicated with the first cavity and the outside of the microphone packaging structure.

9. The microphone package structure of claim 1, wherein the first recess inner wall surface is provided with a metal layer.

10. The microphone package structure of claim 1, wherein the microphone chip and the substrate are fixed by a glue, and the glue on the inner portion of the second cavity overflows into the first recess.

11. A method for forming a microphone packaging structure is characterized by comprising the following steps:

providing a substrate and a microphone chip, wherein a first concave part is formed on the surface of the substrate, the microphone chip comprises a pressure sensing layer and a supporting structure, a second cavity is formed between the supporting structure and the pressure sensing layer, and the top of the supporting structure supports the pressure sensing layer;

fixing the bottom of the supporting structure of the microphone chip on the surface of the substrate, so that the second cavity is communicated with the first concave part, and the first concave part is positioned in the projection of the second cavity on the surface of the substrate;

and providing a packaging shell, fixing the packaging shell on the surface of the substrate, and forming a first cavity between the packaging shell and the substrate, so that the first concave part and the microphone chip are positioned in the first cavity.

12. The method of claim 11, wherein the step of fixing the bottom of the supporting structure of the microphone chip to the surface of the substrate by a glue comprises: coating colloid on the periphery of the first concave part, extruding the bottom of the supporting structure of the microphone chip on the colloid, and curing to fix the microphone chip on the surface of the substrate; after the colloid is extruded, part of the colloid overflows from the inner side of the second cavity into the first concave part.

13. The method of claim 11, wherein a cross-sectional shape of the first recess along a direction parallel to the substrate is a square, a circle, or a polygon, and/or a cross-sectional shape along a direction perpendicular to the substrate is a trapezoid, a rectangle, an arc, or a polygon.

14. The method as claimed in claim 11, wherein the first recess has a step-shaped sidewall, and the bottom of the support structure is fixed to a top step surface of the sidewall of the first recess.

15. The method of claim 14, wherein at least one barrier is disposed between the top step and the first recess, and the bottom of the support structure is fixed to the periphery of the barrier.

16. The method of claim 15, wherein the blocking portion is a plurality of discrete protrusions disposed around the first recess or the blocking portion is a continuous protrusion disposed around the recess.

17. The method of claim 16, wherein the continuous raised surrounding area is square, circular or polygonal.

18. The method as claimed in claim 11, wherein a second recess is formed on the surface of the substrate and surrounds the first recess, and the second recess has a depth smaller than the first recess; and fixing the bottom of the supporting structure of the microphone chip in the second concave part.

19. The method for forming a microphone package structure according to claim 11, further comprising: and forming a metal layer on the inner wall surface of the first concave part.