CN219981037U - MEMS microphone and electronic equipment - Google Patents

Abstract

The utility model provides an MEMS microphone and electronic equipment, wherein the MEMS microphone comprises an MEMS chip, an ASIC chip, a substrate assembly and a shell, wherein the shell is connected with the substrate assembly and forms a back cavity together with the substrate assembly, and the MEMS chip and the ASIC chip are electrically connected and are all positioned in the back cavity; the substrate assembly comprises a packaging substrate and a reinforcing plate, the ASIC chip is mounted on the packaging substrate and is electrically connected with the packaging substrate, the packaging substrate is provided with a through hole communicated with the back cavity, the reinforcing plate is packaged in the through hole and provided with a pickup hole, the MEMS chip is mounted on the reinforcing plate and covers the pickup hole, the thickness of the reinforcing plate is smaller than that of the packaging substrate, and the MEMS chip is at least partially accommodated in the through hole. The MEMS microphone replaces part of the packaging substrate by the reinforcing plate with thinner thickness, the height of the MEMS chip protruding out of the packaging substrate is reduced, and the shell can be reduced in height and thinned, so that the whole MEMS microphone is thinned.

Description

MEMS microphone and electronic equipment

Technical Field

The utility model relates to the field of microphones, in particular to an MEMS microphone and electronic equipment.

Background

In current electronic equipment products, MEMS (Micro-Electro-Mechanical System, micro-electromechanical system) microphones as sound pickup devices are widely used, and the MEMS microphones have advantages of small volume, high sensitivity, low power consumption, flat frequency response, and the like. Currently, a common MEMS microphone generally includes a MEMS chip, an ASIC (Application Specific Integrated Circuit) chip, a package substrate, and a housing, where the package substrate is connected to the housing and forms a back cavity together, the MEMS chip and the ASIC chip are packaged in the back cavity and connected to the package substrate through a DA (Die attach), and electrical connection between the MEMS chip and the ASIC chip and between the ASIC chip and the package substrate can be achieved through WB (wire bonding).

With the development of the light and thin electronic devices, the MEMS microphone needs to be set to be thinner, and the MEMS chip is thicker than the ASIC chip, which results in that the thickness of the MEMS microphone is limited by the thickness of the MEMS chip.

Disclosure of Invention

The utility model provides an MEMS microphone and electronic equipment, which solve the problem that the thickness of the traditional MEMS microphone is limited by the thickness of an MEMS chip and cannot be set thinner.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

in a first aspect, there is provided a MEMS microphone, including a MEMS chip, an ASIC chip, a substrate assembly, and a housing, where the housing is connected to the substrate assembly and forms a back cavity with the substrate assembly, and the MEMS chip and the ASIC chip are electrically connected and both are located in the back cavity; the substrate assembly comprises a packaging substrate and a reinforcing plate, the ASIC chip is mounted on the packaging substrate and is electrically connected with the packaging substrate, the packaging substrate is provided with a through hole communicated with the back cavity, the reinforcing plate is packaged in the through hole and provided with a pickup hole, the MEMS chip is mounted on the reinforcing plate and covers the pickup hole, the thickness of the reinforcing plate is smaller than that of the packaging substrate, and the MEMS chip is at least partially accommodated in the through hole. That is, the MEMS chip is at least partially accommodated in the mounting groove formed by the reinforcing plate and the package substrate, and at this time, the height of the MEMS chip protruding from the package substrate is equal to the height of the MEMS chip per se minus the groove depth of the mounting groove.

The MEMS microphone replaces part of the packaging substrate by the reinforcing plate with thinner thickness, and the thickness of the substrate component provided with the MEMS chip part is thinned, so that the height of the MEMS chip protruding out of the packaging substrate is reduced, the shell can be reduced in height and thinned, and the whole MEMS microphone is thinned. The MEMS microphone can be provided with the through holes and the reinforcing plate on the basis of the current common MEMS microphone, other structures of the current MEMS microphone do not need to be changed, the process difficulty is low, and the influence on an industrial chain is small.

As one embodiment, the hardness of the reinforcing plate is larger than that of the packaging substrate, so that the structural strength of the MEMS microphone is ensured under the condition of thinner thickness, and the influence on the product yield is reduced.

As one example, the MEMS chip is spaced from the perforated hole wall. Therefore, the perforated hole wall can be prevented from wearing the edge of the MEMS chip when the MEMS chip is mounted on the reinforcing plate, and an adjustment space is provided for the position setting of the MEMS chip.

As one embodiment, the package substrate has a first surface and a second surface opposite to each other, the through hole penetrates through the first surface and the second surface, the reinforcing plate has a first plate surface with the same orientation as the first surface and a second plate surface with the same orientation as the second surface, the pick-up hole penetrates through the first plate surface and the second plate surface, the first plate surface is lower than the first surface, the MEMS chip is arranged on the first plate surface, and the second surface of the package substrate is provided with a bonding pad. The packaging substrate and the reinforcing plate are both flat, so that the processing and the butt joint of the packaging substrate and the reinforcing plate can be conveniently realized, other processing procedures are not needed, and the cost is saved.

As one embodiment, the housing and the ASIC chip are both disposed on the first surface. Therefore, the shell and the ASIC chip do not occupy the space for arranging the circuit in the packaging substrate, and the normal wiring of the packaging substrate is ensured.

As one embodiment, the first board surface is connected to the second surface so as to achieve rapid installation of the reinforcing plate and the packaging substrate.

As one embodiment, the reinforcing plate is provided with a relief hole, and the relief Kong Birang is used for avoiding affecting the welding between the bonding pad and the control main board.

As one embodiment, the reinforcing plate is embedded in the packaging substrate so as to reduce the height difference between the bonding pad and the sealing ring support, and the bonding pad, the sealing ring and the control main board are conveniently connected.

As one embodiment, the packaging substrate is provided with an avoidance groove on the second surface, the perforation penetrates to the bottom of the avoidance groove, and the first plate surface is abutted to the bottom of the avoidance groove. Thus, the MEMS microphone positions the reinforcing plate by arranging the avoidance grooves, and the total thickness of the substrate assembly is reduced.

As one embodiment, the perforated hole wall is spaced from the side wall of the avoidance groove, and the reinforcing plate can realize circumferential sealing of the perforation by directly bonding the first plate surface and the bottom of the avoidance groove, so that the sealing reliability is improved, and the reinforcing plate is convenient to realize quick connection with the packaging substrate.

As one embodiment, the second plate surface is flush with the second surface.

As one embodiment, the packaging substrate further has an edge surface connected to the first surface and the second surface, and the avoidance groove is communicated to the edge surface of the packaging substrate. At the moment, the reinforcing plate can be pushed into the avoidance groove from one side of the avoidance groove, so that the reinforcing plate and the packaging substrate can be conveniently assembled.

As one embodiment, the edge of the reinforcing plate is flush with the edge surface, so that the surface of the substrate assembly is smooth, and the connection between the substrate assembly and the control main board is facilitated.

As one embodiment, the side walls of the avoidance grooves are arranged in a closed manner, so that the space available for wiring of the packaging substrate is increased.

As one embodiment, the MEMS microphone further includes a sealing ring connected to the second plate surface and disposed around the sound pick-up hole. The sealing ring can seal the gap between the reinforcing plate and the control main board in the circumferential direction of the pickup hole so as to prevent air leakage when the air flow passing through the through hole of the control main board flows through the pickup hole again.

As one embodiment, the packaging substrate is provided with a bonding pad on the second surface, and the bonding pad is flush with the sealing ring, so that parallel stable installation between the substrate assembly and the control main board is ensured, and the MEMS microphone is prevented from being skewed.

In a second aspect, an electronic device is provided comprising a MEMS microphone as described in the embodiments above. The electronic equipment can realize integral thinning by arranging the MEMS microphone, and better meets the requirements of users on thinness.

Drawings

FIG. 1 is a cross-sectional view of a MEMS microphone of the current general type;

FIG. 2 is a cross-sectional view of a MEMS microphone provided in one embodiment of the utility model;

FIG. 3 is a bottom view of the MEMS of FIG. 2;

FIG. 4 is a cross-sectional view of a MEMS microphone provided in another embodiment of the utility model;

FIG. 5 is a bottom view of the MEMS of FIG. 4;

FIG. 6 is a cross-sectional view of the MEMS microphone provided in FIG. 5 in another embodiment;

FIG. 7 is a bottom view of the MEMS of FIG. 6;

fig. 8 is an assembly step diagram of the MEMS microphone 100.

Reference numerals illustrate:

100', MEMS microphone; 10', MEMS chip; 20', ASIC chip; 30', a package substrate; 40', a housing; 50', 60', gold wires;

100. a MEMS microphone; 101. a back cavity; 10. a MEMS chip; 20. an ASIC chip; 30. a substrate assembly; 301. perforating; 302. a sound pick-up hole; 303. avoidance holes; 304. an avoidance groove; 31. packaging a substrate; 32. a reinforcing plate; 311. a bonding pad; 321. a seal ring; 3101. a first surface; 3102. a second surface; 3103. edge surfaces; 3201. a first panel; 3202. a second panel; 40. a housing; 50. 60, gold wires.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present utility model and should not be construed as limiting the utility model.

In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element in question must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In order to clearly describe the technical solution of the embodiments of the present utility model, in the embodiments of the present utility model, the words "first", "second", etc. are used to distinguish the same item or similar items having substantially the same function and effect. For example, the first limiting portion and the second limiting portion are only for distinguishing different limiting portions, and are not limited in sequence. It will be appreciated by those of skill in the art that the words "first," "second," and the like do not limit the amount and order of execution, and that the words "first," "second," and the like do not necessarily differ.

In the present utility model, the words "in one embodiment" or "for example" are used to mean an example, illustration, or description. Any embodiment or design described herein as "in one embodiment" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of the word "in one embodiment" or "for example" is intended to present the relevant concepts in a concrete fashion.

In the present utility model, unless explicitly specified and limited otherwise, the terms "connected," "connected," and the like are to be construed broadly, and may be fixedly connected, detachably connected, or integrally formed, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent.

In current electronic equipment products, MEMS (Micro-Electro-Mechanical System, micro-electromechanical system) microphones as sound pickup devices are widely used, and the MEMS microphones have advantages of small volume, high sensitivity, low power consumption, flat frequency response, and the like.

Referring to fig. 1, a conventional MEMS microphone 100 'generally includes a MEMS chip 10', an ASIC (Application Specific Integrated Circuit ) chip, a package substrate 30', and a housing 40', wherein the package substrate 30 'is connected to the housing 40' and encloses together to form a back cavity, and the MEMS chip 10 'and the ASIC chip 20' are packaged in the back cavity and electrically connected to each other, wherein the MEMS chip 10 'and the ASIC chip 20' are connected to the package substrate 30 'through a DA (Die attach) to realize mechanical connection between the MEMS chip 10' and the ASIC chip 20 'and the package substrate 30'. Electrical connection between the MEMS chip 10 'and the ASIC chip 20' and between the ASIC chip 20 'and the package substrate 30' can be achieved by WB (wire bonding). The package substrate 30' is provided with a sound pick-up hole, the MEMS chip 10' covers the sound pick-up hole, sound signals can enter the back cavity through the sound pick-up hole and cause vibration of a vibrating diaphragm in the MEMS chip 10', the MEMS chip 10' can convert the sound signals into electric signals through vibration of the vibrating diaphragm and transmit the electric signals to the ASIC chip 20', and the ASIC chip 20' can output the processed electric signals to an external circuit through an effective circuit on the package substrate 30 '.

With the development of light and thin electronic devices, the MEMS microphone 100' needs to be set to be thinner, the thickness of the MEMS chip 10' is generally 0.33mm, the thickness of the ASIC chip 20' is generally 0.11mm, and the thickness of the MEMS chip 10' is about 0.2mm thicker than the ASIC chip 20', which results in the limitation of the thickness of the MEMS microphone 100' to the thickness of the MEMS chip 10 '. Reducing the thickness of the MEMS microphone 100' has a positive effect on reducing the overall thickness of the electronic device. Therefore, it is necessary to provide a MEMS microphone 100' having a thinner thickness.

For this reason, referring to fig. 2, the present utility model provides a MEMS microphone 100 and an electronic device, wherein the MEMS microphone 100 has a thinner thickness than the conventional MEMS microphone 100, and has low process difficulty and small influence on the industrial chain. The electronic device comprises the MEMS microphone 100 and pick up sound through the MEMS microphone 100, wherein the MEMS microphone 100 can be arranged on a control main board of the electronic device. The electronic device includes, but is not limited to, a mobile phone, a tablet computer, a notebook computer, an electronic reader, an intelligent wearable device, a vehicle-mounted device, a palm computer (Personal Digital Assistant, PDA) and the like, and the electronic device can be suitable for ultra-thin scenes.

Referring to fig. 2, the MEMS microphone 100 includes a MEMS chip 10, an ASIC chip 20, a substrate assembly 30, and a housing 40.

The housing 40 may be connected to the substrate assembly 30 in a cover shape, the housing 40 and the substrate assembly 30 together enclose a back cavity 101, and the mems chip 10 and the ASIC chip 20 are both located in the back cavity 101 and are both disposed on the substrate assembly 30. The MEMS chip 10 may be electrically connected to the ASIC chip 20 through a gold wire 50, the ASIC chip 20 is electrically connected to a circuit on the substrate assembly 30 through a gold wire 60, and the housing 40 may be made of a metal material, such as an iron housing 40.

The substrate assembly 30 includes a package substrate 31 and a stiffener 32. The package substrate 31 may be a Printed Circuit Board (PCB) and is used for electrical connection with a control motherboard of the electronic device. The ASIC chip 20 is mounted on the package substrate 31 and is electrically connected to the package substrate 31. The package substrate 31 is provided with a through hole 301 communicating with the back cavity 101, and the reinforcing plate 32 is encapsulated in the through hole 301, that is, the reinforcing plate 32 can seal the through hole 301. The reinforcing plate 32 is provided with a sound pickup hole 302, and the sound pickup hole 302 communicates with the back cavity 101. The MEMS chip 10 is mounted on the reinforcing plate 32, and the MEMS chip 10 is housed in the sound pickup hole 302 so as to sufficiently receive the sound signal transmitted from the outside into the sound pickup hole 302. The central axis of the MEMS chip 10 coincides with the central axis of the pick-up hole 302 to ensure that the diaphragm of the MEMS is uniformly stressed. The thickness of the reinforcing plate 32 is smaller than that of the package substrate 31, so that the reinforcing plate 32 and the package substrate 31 together form a mounting groove. The MEMS chip 10 is at least partially accommodated in the through hole 301, that is, the MEMS chip 10 is at least partially accommodated in the mounting groove, at this time, the height of the MEMS chip 10 protruding from the package substrate 31 is equal to the height of the MEMS chip 10 minus the groove depth of the mounting groove, and compared with the MEMS chip 10 directly mounted on the package substrate 31, the height of the MEMS chip 10 protruding from the package substrate 31 of the MEMS microphone 100 is lower, so that the height of the housing 40 can be set lower, thereby reducing the overall height of the MEMS microphone 100 and realizing the thinning of the MEMS microphone 100.

The MEMS microphone 100 replaces part of the package substrate 31 with the stiffener 32 with a thinner thickness, and the thickness of the substrate assembly 30 provided with the MEMS chip 10 is reduced, so that the height of the MEMS chip 10 protruding from the package substrate 31 is reduced, and the housing 40 can be reduced in height and thinned, thereby realizing the thinning of the whole MEMS microphone 100. The MEMS microphone 100 can be provided with the through holes 301 and the reinforcing plate 32 on the basis of the MEMS microphone 100 which is commonly used at present, other structures of the MEMS microphone 100 at present are not required to be changed, the process difficulty is low, and the influence on an industrial chain is small.

The package substrate 31 is a package substrate 31 commonly used for the MEMS microphone 100, and the thickness of the package substrate is generally 0.25-0.3mm, the thickness of the reinforcing plate 32 can be set to be 0.05-0.08mm, and the hardness of the reinforcing plate 32 is greater than that of the package substrate 31, so that the structural strength of the MEMS microphone 100 is ensured under the condition of thinner thickness, and the influence on the yield of products is reduced. The material of the reinforcing plate 32 includes, but is not limited to, steel, silicon, ceramic substrate, etc., and the wires may be disposed in the reinforcing plate 32 as required. The connection of the housing 40 to the substrate assembly 30 means that the housing 40 may be completely mounted to the package substrate 31, or may be partially mounted to the substrate assembly 30 and partially mounted to the stiffener plate 32.

Specifically, referring to fig. 2, the package substrate 31 has a first surface 3101, a second surface 3102 and an edge surface 3103, the first surface 3101 is parallel to and opposite to the second surface 3102, the edge surface 3103 is in contact with the first surface 3101 and the second surface 3102, and is disposed around the first surface 3101 and the second surface 3102, and the through hole 301 penetrates through the first surface 3101 and the second surface 3102. The reinforcing plate 32 has a first plate surface 3201 and a second plate surface 3202, the first plate surface 3201 and the first surface 3101 are oriented in the same direction, the second plate surface 3202 and the second surface 3102 are oriented in the same direction, the first plate surface 3201 is parallel to the second plate surface 3202, and the sound pickup hole 302 penetrates the first plate surface 3201 and the second plate surface 3202. The first plate surface 3201 is lower than the first surface 3101, at this time, the first plate surface 3201 forms a groove bottom surface of the mounting groove, the MEMS chip 10 is mounted on the first plate surface 3201, and the mounting manner of the MEMS chip 10 and the first plate surface 3201 may be bonding or welding. The package substrate 31 and the reinforcing plate 32 are both flat, so that the two can be conveniently processed and butted, other processing procedures are not needed, and the cost is saved.

The thickness of the package substrate 31 refers to the distance between the first surface 3101 and the second surface 3102, the thickness of the stiffener 32 refers to the distance between the first plate surface 3201 and the second plate surface 3202, and the height of the MEMS chip 10 protruding from the package substrate 31 refers to the height of the upper surface of the MEMS chip 10 away from the stiffener 32 protruding from the first surface 3101. The height of the MEMS chip 10 protruding from the package substrate 31 refers to the height of the upper surface of the MEMS chip 10 facing away from the stiffener 32 protruding from the first surface 3101.

Referring to fig. 2, the housing 40 and the ASIC chip 20 are disposed on the first surface 3101, so that the housing 40 and the ASIC chip 20 do not occupy the space of the circuit disposed in the package substrate 31, and normal routing of the package substrate 31 is ensured. The housing 40 includes a cover plate and a side plate, the side plate is enclosed at the edge of the cover plate to form a cover-shaped structure together with the cover plate, and one end of the side plate far away from the cover plate is welded with the first surface 3101. The cover plate may be a flat plate, and its shape includes, but is not limited to, square, round, or irregular, so that the housing 40 can form a minimum back cavity 101 that can accommodate the MEMS chip 10 and the ASIC chip 20. The cover plate may also have a stepped structure to accommodate the different heights of the MEMS chip 10 and ASIC chip 20 protruding from the first surface 3101. For aesthetic reasons, the shape of the package substrate 31 may be the same as the shape of the cover plate, and the edge surface 3103 of the package substrate 31 is flush with the side of the side plate facing away from the back cavity 101.

It should be noted that, since the housing 40 is generally made of iron, the housing 40 needs to be spaced from the MEMS chip 10, the ASIC chip 20, the gold wires 50 and the gold wires 60 to avoid short circuit. The gold wires 50 electrically connecting the MEMS chip 10 and the ASIC chip 20 are connected to the top of the MEMS chip 10 and the top of the ASIC chip 20, and are bent into an arc shape, the gold wires 60 electrically connecting the ASIC chip 20 and the package substrate 31 are connected to the top of the ASIC chip 20 and the first surface 3101 of the package substrate 31, and are bent into an arc shape, and the space between the cover plate and the MEMS chip 10 needs to be generally limited to about 0.3mm because the housing 40 needs to consider the arc heights of the gold wires 50 and the gold wires 60 and reduce the arc heights.

In other embodiments, the bottom of the MEMS chip 10 may be embedded in the stiffener 32, or a groove may be formed in the stiffener 32, where the bottom surface of the groove forms the first plate surface 3201, and the pick-up hole 302 penetrates into the groove, and the MEMS chip 10 is mounted in the groove, which is not limited herein. The bottom of the ASIC chip 20 may also be embedded in the package substrate 31, or a second recess may be formed on the first surface 3101 side of the package substrate 31, where the ASIC chip 20 is mounted, without limitation. The housing 40 may also be embedded in the package substrate 31 or sleeved outside the package substrate 31, which is not limited herein. The package substrate 31 may have a step structure on both the first surface 3101 and the second surface 3102 to fit the housing 40 or the control motherboard.

Referring to fig. 2, to facilitate the mounting of the MEMS chip 10 in the through hole 301, the cross-sectional size of the through hole 301 is larger than that of the MEMS chip 10, and after the MEMS chip 10 is mounted to the stiffener plate 32, the MEMS chip 10 is spaced apart from the wall of the through hole 301. In this way, the wall of the through hole 301 is prevented from wearing the edge of the MEMS chip 10 when the MEMS chip 10 is mounted to the reinforcing plate 32, and an adjustment space is provided for the position setting of the MEMS chip 10. To ensure that the MEMS chip 10 is evenly spaced from the walls of the through-hole 301, the center axis of the through-hole 301 may coincide with the center axis of the pickup hole 302. Wherein the cross-sectional shape of the perforation 301 may be the same as the cross-sectional shape of the MEMS.

Referring to fig. 2 and 3, a trace is disposed on the package substrate 31, the ASIC chip 20 is electrically connected to the trace of the package substrate 31 through a gold wire 60, a bonding pad 311 electrically connected to the trace is disposed on the second surface 3102 of the package substrate 31, one or more bonding pads 311 may be disposed on the second surface of the package substrate 31, the number of bonding pads 311 may be set according to the number of electrical connection lines between the ASIC chip 20 and the control motherboard, and the MEMS microphone 100 is soldered to the control motherboard of the electronic device through the bonding pads 311 and electrically connected to the trace on the control motherboard through the bonding pads 311, so as to realize control of the MEMS microphone 100 by the control motherboard. In the illustrated embodiment, the pads 311 are provided in plurality, and the plurality of pads 311 are arranged in an array and are disposed at intervals. The package substrate 31 is soldered to the control motherboard via the plurality of pads 311, so as to improve the connection stability and connection strength between the package substrate 31 and the control motherboard.

When the MEMS microphone 100 is mounted on the control board, it is necessary to face the through-hole 301 on the control board and seal between the reinforcing plate 32 and the control board to prevent air leakage.

Optionally, referring to fig. 2 and 3, a sealing ring 321 may be disposed on the second surface 3202 of the reinforcing plate 32 around the hole of the through hole 301, and the sealing ring 321 also surrounds the hole of the through hole on the main board. The reinforcing plate 32 is in sealing connection with the control main board through the sealing ring 321, and the sealing ring 321 can seal a gap between the reinforcing plate 32 and the control main board in the circumferential direction of the pickup hole 302, so as to prevent air leakage when the air flow passing through the through hole of the control main board flows through the pickup hole 302 again. The sealing connection mode can be welding or bonding. When the package substrate 31 needs to be electrically connected to the control motherboard by means of the stiffener 32, the package substrate 31 and the stiffener 32 may be bonded by conductive adhesive, the stiffener 32 may be made of steel, and the sealing ring 321 may be made of conductive material.

The sealing ring 321 may be a solder plating layer formed on the second plate surface 3202, where the solder plating layer may be nickel-tin plating or nickel-gold plating. The sealing ring 321 may be annular, and at this time, the central axis of the central axis pick-up hole 302 of the sealing ring 321 coincides with the central axis of the through hole of the main board, so as to ensure that the air flow stably enters the back cavity 101. The cross-sectional area of the inner annular surface of the sealing ring 321 may be larger than the cross-sectional area of the sound pick-up hole 302, and the sealing ring 321 may be spaced from the sound pick-up hole 302, so as to reduce the influence of the setting error of the sealing ring 321 and the welding error between the sealing ring 321 and the control main board on the air flow entering the back cavity 101.

It should be noted that, the sealing ring 321 needs to be made of a hard material to provide sufficient supporting force for the MEMS microphone 100 at the portion provided with the reinforcing plate 32, so as to improve the connection strength and stability between the MEMS microphone 100 and the control motherboard.

There are two ways of packaging the stiffener 32 on the package substrate 31, and several embodiments are listed below.

As an embodiment, referring to fig. 2 and 3, the stiffener 32 is disposed on the second surface 3102 side of the package substrate 31, and the first plate surface 3201 is connected to the second surface 3102, and the stiffener 32 covers the hole of the through hole 301 on the second surface 3102, so as to achieve rapid installation of the stiffener 32 and the package substrate 31. The height of the MEMS chip 10 protruding from the package substrate 31 is the thickness of the MEMS chip 10 minus the thickness of the package substrate 31.

If the height of the MEMS chip 10 protruding from the package substrate 31 is greater than the height of the ASIC chip 20, the total thickness of the MEMS microphone 100 is equal to the sum of the thickness of the stiffener 32, the thickness of the MEMS chip 10, the minimum height of the gap between the cover and the MEMS chip 10, and the thickness of the cover, and the thickness of the MEMS microphone 100 is the difference between the thickness of the package substrate 31 and the thickness of the stiffener 32 compared to the conventional MEMS microphone 100.

If the height of the MEMS chip 10 protruding from the package substrate 31 is smaller than the height of the ASIC chip 20, the total thickness of the MEMS microphone 100 is equal to the sum of the thickness of the stiffener 32, the thickness of the package substrate 31, the minimum height of the gap between the cover plate and the ASIC chip 20, and the thickness of the cover plate, and the thickness of the MEMS microphone 100 is smaller than the thickness of the MEMS chip 10 minus the thickness of the ASIC chip 20 and minus the thickness of the stiffener 32 compared to the conventional MEMS microphone 100.

In this embodiment, the reduced thickness is approximately 0.2mm and the total thickness of the mems microphone 100 is approximately 0.9-1.0mm.

The area of the reinforcing plate 32 may be larger to improve the stability of supporting the package substrate 31 and the structural strength of the substrate assembly 30. At this time, the reinforcing plate 32 may be provided with the avoiding holes 303, and the avoiding holes 303 avoid the bonding pads 311, so as to avoid affecting the bonding of the bonding pads 311 and the control motherboard.

In the embodiment shown in fig. 2, the edge of the stiffener 32 is flush with the edge of the package substrate 31 to further improve the stability of the support of the package substrate 31 and to improve the aesthetic appearance of the MEMS microphone 100.

It should be noted that, to electrically connect the pads 311 to the control motherboard, a step structure may be disposed on the second surface 3102 of the package substrate 31 or the control motherboard to ensure that the pads 311 and the control motherboard can be soldered.

As another embodiment, the reinforcing plate 32 is embedded in the package substrate 31 to reduce the height difference between the bonding pad 311 and the support of the sealing ring 321, so as to facilitate the connection between the bonding pad 311 and the sealing ring 321 and the control motherboard. While the thickness of the substrate assembly 30 as a whole may be reduced, thereby further thinning the MEMS microphone 100.

For example, referring to fig. 4 and 5, the package substrate 31 has an avoidance groove 304 formed on the second surface 3102, the avoidance groove 304 is avoided by the bonding pad 311, the through hole 301 penetrates to the bottom of the avoidance groove 304, the reinforcing plate 32 may be at least partially contained in the avoidance groove 304, and the first plate surface 3201 abuts against the bottom of the avoidance groove 304. At this time, the total thickness of the substrate assembly 30 is equal to the thickness of the package substrate 31 plus the thickness of the stiffener plate 32 minus the depth of the relief groove 304, so that the MEMS microphone 100 positions the stiffener plate 32 by providing the relief groove 304, and the total thickness of the substrate assembly 30 is reduced.

The size of the cross section of the avoidance groove 304 may be greater than or equal to the size of the cross section of the reinforcing plate 32 so as to accommodate the package substrate 31. In the illustrated embodiment, the size of the cross-section of the relief groove 304 is adapted to the size of the cross-section of the stiffener plate 32 to facilitate positioning of the stiffener plate 32.

The bonding pad 311 is also flush with the sealing ring 321, so as to ensure parallel and stable installation between the substrate assembly 30 and the control motherboard, and prevent the MEMS microphone 100 from being skewed.

In other embodiments, the reinforcing plate 32 may be adhered to the wall of the perforation 301 or embedded within the wall of the perforation 301, so long as a seal against the perforation 301 is achieved.

Optionally, referring to fig. 4 and 6, the reinforcing plate 32 is completely accommodated in the avoidance groove 304, and the second plate surface 3202 is flush with the second surface 3102, so as to ensure that the surface of the substrate assembly 30 is flat, and facilitate connection between the substrate assembly 30 and the control motherboard. The height of the MEMS chip 10 protruding from the package substrate 31 is the thickness of the MEMS chip 10 plus the thickness of the stiffener 32 minus the thickness of the package substrate 31.

If the height of the MEMS chip 10 protruding from the package substrate 31 is greater than the height of the ASIC chip 20, the total thickness of the MEMS microphone 100 is equal to the sum of the thickness of the stiffener 32, the thickness of the MEMS chip 10, the minimum height of the gap between the cover and the MEMS chip 10, and the thickness of the cover, and the thickness of the MEMS microphone 100 is the difference between the thickness of the package substrate 31 and the thickness of the stiffener 32 compared to the conventional MEMS microphone 100.

If the height of the MEMS chip 10 protruding from the package substrate 31 is smaller than the height of the ASIC chip 20, the total thickness of the MEMS microphone 100 is equal to the sum of the thickness of the package substrate 31, the thickness of the ASIC chip 20, the minimum spacing height between the cover plate and the ASIC chip 20, and the thickness of the cover plate, and the thickness of the MEMS microphone 100 is the difference between the thickness of the MEMS chip 10 and the thickness of the ASIC chip 20 compared to the conventional MEMS microphone 100.

In this embodiment, the reduced thickness is approximately 0.2mm and the total thickness of the mems microphone 100 is approximately 0.9-1.0mm.

Referring to fig. 4 and 6, the hole wall of the through hole 301 is spaced from the side wall of the avoidance groove 304, a step structure is formed between the hole wall of the through hole 301 and the groove bottom of the avoidance groove 304, the step structure is arranged around the through hole 301, the bonding between the first plate surface 3201 and the groove bottom of the avoidance groove 304 is the bonding between the first plate surface 3201 and the table top of the step structure, at this time, the reinforcing plate 32 can realize circumferential sealing of the through hole 301 directly through the bonding between the first plate surface 3201 and the groove bottom of the avoidance groove 304, sealing reliability is improved, and quick connection between the reinforcing plate 32 and the packaging substrate 31 is convenient. In the illustrated embodiment, the central axis of the relief groove 304 coincides with the central axis of the perforation 301 and the central axis of the reinforcing plate 32.

In other embodiments, the thickness of the stiffener plate 32 may be less than the depth of the relief groove 304 to further reduce the weight of the MEMS microphone 100, and the seal ring 321 may be thicker to achieve a sealed connection with the control motherboard. The thickness of the reinforcing plate 32 may also be greater than the depth of the avoiding groove 304, and the edge of the reinforcing plate 32 on the first plate surface 3201 is provided with a step structure, through which the reinforcing plate 32 may be connected with the second surface 3102 of the package substrate 31, so as to improve structural stability. The hole wall of the through hole 301 may be partially connected to a portion of the side wall of the avoidance groove 304, and at this time, the reinforcing plate 32 may be connected to the side wall of the avoidance groove 304 in a sealing manner by the edge corresponding to the connection portion, so as to seal the through hole 301 by the reinforcing plate 32.

Optionally, referring to fig. 4 and 5, the relief groove 304 is connected to at least one right angle edge of the edge surface 3103 of the package substrate 31. In the embodiment shown in fig. 5, the avoidance groove 304 is communicated to three right-angle edges of the edge surface 3103 of the package substrate 31, so that the number of groove side walls of the avoidance groove 304 for preventing the reinforcing plate 32 from being installed is reduced, the package substrate 31 only forms a step structure between the avoidance groove 304 and the bonding pad 311, and at this time, the reinforcing plate 32 can be pushed into the avoidance groove 304 from multiple directions, so that the reinforcing plate 32 and the package substrate 31 can be assembled quickly. At this time, the three edges of the stiffener 32 may be aligned with the three right-angle edges corresponding to the edge surface 3103, so as to align the stiffener 32, and the stiffener 32 may have a larger area, so as to improve the structural strength of the substrate assembly 30, increase the connection area between the stiffener 32 and the package substrate 31, improve the structural stability, and maintain the aesthetic degree of the MEMS microphone 100.

Alternatively, referring to fig. 6 and 7, the side walls of the avoidance groove 304 are closed, that is, the side walls of the avoidance groove 304 are spaced from the edge surface 3103 of the package substrate 31, so as to increase the space available for routing the package substrate 31.

Referring to fig. 8, the assembly steps of the MEMS microphone 100 are as follows: the packaging substrate 31 is bonded with the reinforcing plate 32, the ASIC chip 20 is disposed on the packaging substrate 31 by a Die Attach (Die Attach) technology, the MEMS chip 10 is disposed on the reinforcing plate 32, and Wire Bonding (Wire Bonding) is performed, that is, the MEMS chip 10 and the ASIC chip 20 are electrically connected by a gold Wire 50, the ASIC chip 20 and the packaging substrate 31 are electrically connected by another gold Wire 60, then a protective adhesive is applied to the ASIC chip 20, automatic optical inspection (Automated Optical Inspection, AOI) is performed, and finally the case 40 is welded to the substrate assembly 30 by SMT, thereby completing the assembly of the MEMS.

The present utility model also provides an electronic device including the MEMS microphone 100 in the above embodiments. The MEMS microphone 100 has the same structure as the MEMS microphone 100 in the above embodiments, and functions are the same, and are not described here again. The electronic device can realize overall thinning by arranging the MEMS microphone 100, and better meets the requirement of users on thinness.

Finally, it should be noted that: the present utility model is not limited to the above embodiments, and any changes or substitutions within the technical scope of the present utility model should be covered by the scope of the present utility model. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.

Claims (17)

1. The MEMS microphone is characterized by comprising an MEMS chip, an ASIC chip, a substrate assembly and a shell, wherein the shell is connected with the substrate assembly and forms a back cavity together with the substrate assembly, and the MEMS chip and the ASIC chip are electrically connected and are both positioned in the back cavity;

the substrate assembly comprises a packaging substrate and a reinforcing plate, the ASIC chip is mounted on the packaging substrate and is electrically connected with the packaging substrate, the packaging substrate is provided with a through hole communicated with the back cavity, the reinforcing plate is packaged in the through hole and provided with a pickup hole, the MEMS chip is mounted on the reinforcing plate and covers the pickup hole, the thickness of the reinforcing plate is smaller than that of the packaging substrate, and the MEMS chip is at least partially accommodated in the through hole.

2. The MEMS microphone of claim 1, wherein the stiffener plate has a hardness greater than a hardness of the package substrate.

3. The MEMS microphone of claim 1, wherein the MEMS chip is spaced from the perforated hole wall.

4. A MEMS microphone according to any one of claims 1-3, wherein the package substrate has a first surface and a second surface opposite to each other, the through hole penetrates through the first surface and the second surface, the stiffener has a first plate surface facing the first surface and a second plate surface facing the second surface, the pick-up hole penetrates through the first plate surface and the second plate surface, the first plate surface is lower than the first surface, the MEMS chip is disposed on the first plate surface, and the package substrate is disposed with a bonding pad on the second surface.

5. The MEMS microphone of claim 4, wherein the housing and the ASIC chip are both disposed on the first surface.

6. The MEMS microphone of claim 4, wherein the first plate surface is connected to the second surface.

7. The MEMS microphone of claim 6, wherein the stiffener plate is formed with relief holes, the relief Kong Birang the bonding pads.

8. The MEMS microphone of claim 4, wherein the stiffener is embedded in the package substrate.

9. The MEMS microphone of claim 8, wherein the package substrate has an avoidance groove formed in the second surface, the through hole penetrates to a groove bottom of the avoidance groove, and the first plate surface abuts against the groove bottom of the avoidance groove.

10. The MEMS microphone of claim 9, wherein the perforated hole wall is spaced from the slot sidewall of the relief slot.

11. The MEMS microphone of claim 9, wherein the second plate surface is flush with the second surface.

12. The MEMS microphone of claim 9, wherein the package substrate further has an edge surface that interfaces with the first surface and the second surface, the relief groove communicating to the edge surface of the package substrate.

13. The MEMS microphone of claim 12, wherein an edge of the stiffening plate is flush with the edge face.

14. The MEMS microphone of claim 9, wherein the channel side walls of the relief channel are closed.

15. The MEMS microphone of claim 4, further comprising a seal ring coupled to the second plate surface and disposed around the pickup aperture.

16. The MEMS microphone of claim 15, wherein the second surface of the package substrate is provided with a bonding pad that is flush with the sealing ring.

17. An electronic device comprising a MEMS microphone as claimed in any of claims 1 to 16.