CN113411732A

CN113411732A - Microphone packaging structure, earphone and electronic equipment

Info

Publication number: CN113411732A
Application number: CN202110860643.3A
Authority: CN
Inventors: 王韬
Original assignee: Chengdu Xiansheng Technology Co ltd
Current assignee: Chengdu Xiansheng Technology Co ltd
Priority date: 2021-07-28
Filing date: 2021-07-28
Publication date: 2021-09-17

Abstract

The application provides a microphone packaging structure, earphone and electronic equipment, wherein, this microphone packaging structure includes: a printed circuit board; an application specific integrated chip mounted on one side of the printed circuit board; a MEMS microphone covering the ASIC; the special integrated chip and the micro-electro-mechanical system microphone are arranged in a space formed by the shell and the printed circuit board; the shell is provided with a sound receiving hole which is arranged on one side of the shell close to the micro-electro-mechanical system microphone; or, the printed circuit board is provided with a sound receiving hole which is arranged at any position outside the coverage area of the special integrated chip.

Description

Microphone packaging structure, earphone and electronic equipment

Technical Field

The application relates to the technical field of microphones, in particular to a microphone packaging structure, an earphone and electronic equipment.

Background

The microphone generally includes a Micro-Electro-Mechanical System (MEMS) microphone portion and an Application Specific Integrated Circuit (ASIC) portion.

The current layout of microphones is to place the mems microphone part side by side with the asic part. However, the overall structure of the microphone is larger due to the layout mode under the demand of smaller chips.

Disclosure of Invention

In view of the above, an object of the embodiments of the present application is to provide a microphone package structure, an earphone and an electronic device. The problem of larger structure of the current microphone can be alleviated.

In a first aspect, an embodiment of the present application provides a microphone package structure, including:

a printed circuit board;

an application specific integrated chip mounted on one side of the printed circuit board;

a MEMS microphone covering the ASIC;

the shell is covered on the printed circuit board, and the application specific integrated chip and the micro electro mechanical system microphone are arranged in a space formed by the shell and the printed circuit board;

the shell is provided with a sound receiving hole, and the sound receiving hole is arranged on one side of the shell close to the micro-electro-mechanical system microphone; or, the printed circuit board is provided with a sound receiving hole, and the sound receiving hole is arranged at any position outside the coverage area of the special integrated chip.

Optionally, a first accommodating cavity is disposed on a first side of the mems microphone, and the asic is embedded in the first accommodating cavity.

Optionally, the first receiving cavity is cuboidal in shape.

In the above embodiment, the first receiving cavity is provided in a cubic shape, so that the first receiving cavity can better fit with the shape of the application specific integrated chip, and the first receiving cavity does not waste space.

Optionally, a hollow heightening structure is arranged on the printed circuit board;

the micro-electro-mechanical system microphone is covered on the heightening structure;

the padding structure, the printed circuit board and the micro-electro-mechanical system microphone form a second accommodating space;

the application specific integrated chip is installed in the second accommodating space.

In the above embodiment, the raised structure is disposed on the printed circuit board, so that the second accommodating space can better meet the space requirement of the asic, and the asic can be accommodated without changing the size of the cavity of the mems microphone.

Optionally, the thickness of the raised structure is a dimension between 100 and 550 μm;

the thickness of the ASIC is 150-250 μm.

In the above embodiment, the elevation structure and the asic are formed to have the above thicknesses, so that the microphone package can be made smaller even when the asic is accommodated therein.

Optionally, a chip surface of the asic is close to the pcb;

the chip surface of the special integrated chip is electrically connected with the printed circuit board through a conductive structure.

In the above embodiment, the asic is flip-chip bonded, which can reduce the space required for electrical connection and reduce the space required for accommodating the asic, thereby making the microphone package smaller.

Optionally, the method further comprises: bonding gold wires; the micro-electro-mechanical system microphone is electrically connected with the printed circuit board through the gold bonding wire.

Optionally, the mems microphone comprises: a conductive line extending through the MEMS microphone from a first surface of the MEMS microphone to a second surface of the MEMS microphone;

the mems microphone is electrically connected to the printed circuit board through the conductive wire.

In the above embodiments, the mems microphone is electrically connected to the printed circuit board by using a wire penetrating through the mems microphone, so that the size of the microphone package structure can be reduced.

In a second aspect, an embodiment of the present application provides an earphone, including: the microphone packaging structure is provided.

In a third aspect, an embodiment of the present application provides an electronic device, including: the microphone packaging structure is provided.

The microphone packaging structure, the earphone and the electronic equipment provided by the embodiment of the application adopt the special integrated chip to be built in the cavity of the microphone of the micro electro mechanical system, the size of the microphone packaging structure can be reduced, further, the coverage area of the printed circuit board covered by the special integrated chip does not start to sound receiving holes, so that the special integrated chip can be electrically connected with the coverage area, the space required by electrical connection is reduced, and the size of the microphone packaging structure is further reduced.

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a schematic diagram of a prior art condenser MEMS microphone and ASIC;

FIG. 2 is a schematic diagram of a voltage type MEMS microphone and an ASIC;

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

fig. 4 is another schematic structural diagram of a microphone package structure according to an embodiment of the present disclosure;

fig. 5 is a schematic diagram of a printed circuit board and a pad-up structure according to an embodiment of the present disclosure.

Icon: 110-capacitive micro-electromechanical system microphone; 120-a first application specific integrated chip; 210-a voltage mems microphone; 220-a second application specific integrated chip; 300-microphone package structure; 310-a micro-electro-mechanical system microphone; 311-a first receiving cavity; 312-a conductive line; 313-a piezoelectric diaphragm; 314-a substrate; 315-electrode pad; 320-application specific integrated chip; 330-printed circuit board; 340-a housing; 341-sound-absorbing hole; 350-a raised structure; 360-gold bonding wire; 370-solder balls.

Detailed Description

The technical solution in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings or orientations or positional relationships that the application product usually visits when in use, which are merely for convenience of describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present application.

Throughout the description of the present application, it is further noted that, unless expressly stated or limited otherwise, the terms "disposed," "mounted," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, or may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

The current manufacturing process of the capacitive micro-electro-mechanical system microphone is as follows: sequentially growing SiO on the surface of the wafer₂A thin film and a Si thin film; photoetching and etching the surface Si layer to form honeycomb-shaped etching holes; using chemical liquids or gases, on SiO₂The layer is subjected to an isotropic etch, which is isotropic, i.e. centered around the etched hole, with a circleUniformly diffusing the shape to the periphery; and deep silicon etching is carried out on the back surface, so that the structure release of the back plate is realized. As can be understood from the above process, since SiO is used₂The limitation of the isotropic etching process of thin films, circular being a relatively easy shape to obtain and control; the honeycomb grid structure on the front surface of the condenser micro-electro-mechanical system microphone is very fragile and easy to collapse or break, the circular shape can provide better support and strength for a condenser micro-electro-mechanical system microphone chip, and the square diaphragm is easy to break due to the existence of factors such as stress concentration on the edge. For the above two reasons, the diaphragm of the mems microphone chip is generally circular.

Further, the asic for operating with the mems condenser microphone needs to provide a high voltage bias for the mems condenser microphone, so that the prior art first asic 120 includes a signal amplifier and a charge pump as shown in fig. 1, resulting in a large area of the first asic 120. Therefore, based on the structure of the mems microphone 110 and the structure of the asic 120, the package structure corresponding to the mems microphone can only be configured in parallel with the mems microphone.

The inventor of the present application starts from the structure of the mems microphone and the asic, and the piezoelectric mems microphone 210 that is known from the structural point of view may not be made into a circular shape, and the cavity of the piezoelectric mems microphone 210 may be made into a square shape, so that the cavity thereof can be better utilized. In addition, as shown in fig. 2, the piezoelectric mems microphone 210 does not require an asic to provide a high voltage bias, and the second asic 220 required for the piezoelectric mems microphone 210 only requires an amplifier, so that the package structure of the piezoelectric mems microphone can be made smaller. Therefore, based on the above research, the present application provides a microphone package structure, an earphone, and an electronic device, which can overcome the problem of the microphone package structure in the above current situation. The microphone packaging structure provided by the embodiment of the application is more compact, and the microphone packaging structure can be smaller.

The embodiment of the present application provides a microphone package structure 300. The microphone package structure 300 may include: a printed circuit board 330, an application specific integrated chip 320, a mems microphone 310, and a housing 340.

Wherein the asic 320 is mounted on one side of the pcb 330, and the mems microphone 310 is covered on the asic 320.

The mems microphone 310 in this embodiment may be a piezoelectric mems microphone. For example, as shown in fig. 3, the piezoelectric mems microphone may include a substrate 314 and a piezoelectric diaphragm 313.

In one example, the substrate 314 may include: a first silicon layer, a silicon dioxide layer, and a second silicon layer.

The housing 340 is covered on the printed circuit board 330, and the asic 320 and the mems microphone 310 are located in the space formed by the housing 340 and the printed circuit board 330.

In one embodiment, as shown in fig. 3, the housing 340 is provided with a sound-absorbing hole 341, and the sound-absorbing hole 341 is disposed on a side of the housing 340 close to the mems microphone 310.

Illustratively, the acoustic hole 341 shown in FIG. 3 is open above the MEMS microphone 310. For example, when the mems microphone 310 is a cantilever structure, the acoustic hole 341 may be disposed at a position corresponding to a gap of the cantilever structure.

In another embodiment, the printed circuit board 330 is provided with a sound-absorbing hole (not shown), and the sound-absorbing hole is disposed at any position outside the coverage area of the asic 320.

Illustratively, the acoustic hole may be provided in a housing 340 footprint on the printed circuit board 330. For example, the acoustic hole is disposed in the area covered by the housing 340 on the printed circuit board 330 and not covered by the mems microphone 310. For example, the acoustic hole is provided in an area covered by the housing 340 on the printed circuit board 330 and not covered by the asic 320.

As shown in fig. 3, a first receiving cavity 311 is disposed on a first side of the mems microphone 310, and the asic 320 is embedded in the first receiving cavity 311.

Wherein the first receiving cavity 311 may be formed on the first silicon layer and the silicon dioxide layer of the substrate 314.

Illustratively, the first receiving cavity 311 is cuboidal in shape. The bottom area of the cube is not smaller than the area of the asic 320.

Illustratively, the depth of the first receiving cavity 311 may be anywhere between 300 μm-500 μm. For example, the depth of the first receiving cavity 311 may be 300 μm, the depth of the first receiving cavity 311 may be 400 μm, the depth of the first receiving cavity 311 may be 500 μm, and the depth of the first receiving cavity 311 may be 450 μm. The depth of the first receiving cavity 311 may be set according to the size of the asic 320.

As shown in fig. 4, the printed circuit board 330 is provided with a raised structure 350.

The mems microphone 310 is covered on the elevated structure 350. For example, if the mems microphone 310 is a rectangular structure, the raised structure 350 may be a hollow rectangle. Referring to fig. 5, fig. 5 is a schematic view perpendicular to the viewing angle of fig. 4.

The elevated structure 350, the printed circuit board 330 and the mems microphone 310 form a second receiving space, and the asic 320 is mounted in the second receiving space.

Optionally, the thickness of the raised structure 350 is a dimension between 100 and 550 μm. For example, the thickness of the raised structure 350 may be 100- μm, the thickness of the raised structure 350 may be 550 μm, the thickness of the raised structure 350 may be 200 μm, the thickness of the raised structure 350 may be 250 μm, and the like.

Optionally, the thickness of the asic 320 is one dimension between 150 and 250 μm. For example, the asic 320 may have a thickness of 150 μm, the asic 320 may have a thickness of 180 μm, the asic 320 may have a thickness of 200 μm, the asic 320 may have a thickness of 230 μm, the asic 320 may have a thickness of 250 μm, and so on.

The chip surface of the asic 320 is close to the pcb 330, and the chip surface of the asic 320 is electrically connected to the pcb 330 through a conductive structure.

The conductive structure may be a solder ball or other structure having a conductive function.

The chip side may refer to another side of the asic 320 than the substrate.

Illustratively, as shown in fig. 3 or 4, the asic 320 may be inverted so that the chip side may be electrically connected to the pcb 330 through conductive structures. Illustratively, the conductive structure may be a solder ball as shown in fig. 3 or fig. 4.

The electrical connection of the asic 320 to the pcb 330 may be accomplished, for example, by a flip chip bonding process.

Optionally, as shown in fig. 3, the mems microphone 310 includes: a conductive line 312 extending from the first surface of the mems microphone 310 to the second surface of the mems microphone 310.

The mems microphone 310 is electrically connected to the pcb 330 via the conductive wire 312.

Illustratively, the mems microphone 310 is provided with a through hole. As shown in fig. 3, four through holes are shown.

In an alternative embodiment, as shown in FIG. 3, the MEMS microphone 310 is a cantilever beam structure, and at least one through hole is disposed on both sides of the cantilever beam, in the example shown in FIG. 3, two through holes are disposed on each side of the cantilever beam.

In another alternative embodiment, as shown in fig. 3, the mems microphone 310 is a diaphragm type structure, and the mems microphone 310 may be provided with at least one through hole.

The through hole is filled with a conductive material, and the conductive material in the through hole can form a conductive line 312, so as to electrically connect the mems microphone 310 and the pcb 330.

The conductive material may be copper, aluminum, or other metal.

Optionally, the mems microphone 310 may further include an electrode pad 315 connected to the conductive line 312, and the electrode pad 315 may be disposed on a side of the mems microphone adjacent to the printed circuit board 330.

As shown in fig. 3, the electrode pad 315 may be electrically connected to the printed circuit board 330 by a solder ball 370.

In the above embodiment, a Through hole penetrating Through the substrate is formed on the mems microphone 310 by a deep Silicon etching process and filled with a conductive material, so as to form a Through Silicon Via (TSV) structure capable of communicating the upper and lower surfaces of the chip. By using the vertical through silicon interconnection structure, a gold wire is not needed, so that the space required by the microphone packaging structure 300 is further saved, and the microphone packaging structure 300 is smaller.

As shown in fig. 4, the microphone package structure 300 in this embodiment may further include: gold bonding wire 360. The mems microphone 310 is electrically connected to the pcb 330 through the gold bonding wire 360.

In the embodiment of the present application, when the sound drives the piezoelectric mems microphone to move, the piezoelectric layer on the piezoelectric mems microphone will generate a strain. The material of the piezoelectric layer is one that converts strain to electrical charge, and thus the piezoelectric layer converts sound-induced diaphragm motion to electrical charge output. The process does not need a bipolar plate capacitor structure, and the conversion process of the piezoelectric material does not need the participation of bias voltage. The piezoelectric mems microphone 310 chip therefore directly sends the generated charge/voltage signal to the amplifier, eliminating the need for a boost module to provide a high voltage bias. Therefore, the asic 320 chip mated with the mems microphone 310 chip only needs an amplifier module and does not need a boost module, so that the mems microphone requires a smaller size than the capacitive mems, and the asic 320 can be installed in the cavity space of the mems microphone to reduce the size of the microphone package 300.

Furthermore, the cavity of the piezoelectric mems chip is a rectangular cavity space, which can be better adapted to the shape of the asic 320, thereby reducing the idle of the redundant space of the cavity of the piezoelectric mems chip.

Due to the fact that the size of the application-specific integrated chip 320 is small, the application-specific integrated chip 320 can be accommodated in a cavity of the piezoelectric micro electro mechanical system microphone, the problem that the application-specific integrated chip 320 cannot be accommodated in the micro electro mechanical system microphone 310 is solved, packaging and integration of the application-specific integrated chip 320 in the micro electro mechanical system microphone 310 are achieved, the packaging size of the microphone is greatly reduced, and more compact packaging of the microphone is achieved.

Further, in the microphone package structure 300 provided in the embodiment of the present application, the height of the mems microphone 310 can be raised by 100 μm and 500 μm by the raised structure 350 disposed on the pcb 330, so as to counteract a portion of the reduction of the internal space of the mems microphone 310 caused by the mounting of the asic 320. Further, the thickness of the asic 320 is controlled to 180-. Therefore, the reduction of the sensitivity of the mems microphone 310 can be reduced on the basis of the compact packaging of the microphone package 300.

The embodiment also provides an earphone. The headset may include: the microphone package structure 300.

The microphone package structure 300 in this embodiment may be similar to the microphone package structure 300 provided in the above-mentioned embodiment of the microphone package structure 300, and is not described herein again.

The embodiment also provides the electronic equipment. The electronic device may include: the microphone package structure 300.

The electronic device may also comprise other components for fulfilling different requirements. For example, the electronic device may also include a memory and a processor.

For example, the electronic device may be a device for monitoring a target area, and the electronic device may further include an acquisition unit, which may be a camera or the like. The acquisition unit can acquire the image data of the target area according to a set time rule.

Illustratively, the electronic device may be a children's telephone watch, and the electronic device may include a positioning unit. The positioning unit can acquire the positioning information of the child telephone watch according to a set time rule.

The foregoing is illustrative of only alternative embodiments of the present application and is not intended to limit the present application, which may be modified or varied by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A microphone package structure, comprising:

a printed circuit board;

a MEMS microphone covering the ASIC;

2. The microphone package structure of claim 1, wherein the first side of the mems microphone is provided with a first receiving cavity, and the asic is embedded in the first receiving cavity.

3. The microphone packaging structure of claim 2, wherein the first receiving cavity is cuboidal in shape.

4. The microphone package structure of claim 1, wherein a hollow raised structure is disposed on the printed circuit board;

5. The microphone package structure of claim 4, wherein the raised structure has a thickness of 100-550 μm;

the thickness of the ASIC is 150-250 μm.

6. The microphone package structure of any one of claims 1-5, wherein the chip side of the ASIC is proximate to the printed circuit board;

7. The microphone package structure of any one of claims 1 to 5, further comprising: bonding gold wires;

the micro-electro-mechanical system microphone is electrically connected with the printed circuit board through the gold bonding wire.

8. The microphone package structure of any of claims 1-5, wherein the MEMS microphone comprises: a conductive line extending through the MEMS microphone from a first surface of the MEMS microphone to a second surface of the MEMS microphone;

9. An earphone, comprising: a microphone package according to any of claims 1-8.

10. An electronic device, comprising: a microphone package according to any of claims 1-8.