CN113840218A

CN113840218A - Microphone packaging structure and electronic equipment

Info

Publication number: CN113840218A
Application number: CN202110688160.XA
Authority: CN
Inventors: 邱俊峰
Original assignee: Rongcheng Gol Microelectronics Co ltd
Current assignee: Rongcheng Gol Microelectronics Co ltd
Priority date: 2021-06-21
Filing date: 2021-06-21
Publication date: 2021-12-24

Abstract

The invention relates to the technical field of electronic packaging, and particularly discloses a packaging structure of a microphone, which comprises a shell, a circuit board, an MEMS chip, an ASIC chip and a filter device, wherein the circuit board is arranged on the shell; the circuit board comprises a first area and a second area, and the first area is provided with a sound hole penetrating through the circuit board; the shell and the circuit board are covered to form a first cavity, the first area and the second area are positioned in the first cavity, and the first cavity is communicated with the outside through the sound hole; the MEMS chip is arranged in the first area and is opposite to the position of the sound hole; the ASIC chip and the filter device are arranged in the second area, the ASIC chip is superposed above the filter device, and the ASIC chip is electrically connected with the MEMS chip. According to the invention, the ASIC chip and the filter device are overlapped and integrally arranged in the second area of the circuit board, so that the occupied space of the second area on the circuit board is saved, and the overall packaging size of the microphone is reduced.

Description

Microphone packaging structure and electronic equipment

Technical Field

The present invention relates to the field of electronic packaging technologies, and in particular, to a packaging structure of a microphone and an electronic device.

Background

A microphone is an energy conversion device, also called a microphone, a microphone or a microphone, which can convert a sound signal into an electrical signal. With the increasing intelligence of electronic products, more electronic products are equipped with microphones, and in order to meet the requirements of light weight, thinness and miniaturization of electronic products, the size of the microphone needs to be miniaturized as much as possible to save the internal space of the electronic products.

In order to improve the anti-interference capability of the microphone, a filter device is generally required to be added to a microphone circuit in the prior art, and the increase of the filter device undoubtedly increases the overall circuit size of the microphone, so that the occupied space inside an electronic product after the whole microphone is packaged becomes large.

Disclosure of Invention

The invention provides a microphone packaging structure and electronic equipment, which at least solve one problem in the background art.

According to a first aspect of the present invention, there is provided a packaging structure of a microphone, including: the MEMS filter comprises a shell, a circuit board, an MEMS chip, an ASIC chip and a filter device;

the circuit board comprises a first area and a second area, and the first area is provided with a sound hole penetrating through the circuit board;

the shell and the circuit board are covered to form a first cavity, the first area and the second area are positioned in the first cavity, and the first cavity is communicated with the outside through the sound hole;

the MEMS chip is arranged in the first area and is opposite to the position of the sound hole;

the ASIC chip with the filter device sets up in the second region, the ASIC chip coincide in the top of filter device, the ASIC chip with MEMS chip electricity is connected.

Optionally, the filter device is disposed on a surface of the second region, a support structure is disposed on the filter device, and the ASIC chip is attached to a surface of the support structure.

Optionally, the filter device is embedded in the support structure, and the support structure is made of an electronic packaging material.

Optionally, the supporting structure is an inner shell, the inner shell and the second region are covered to form a second cavity, the filter device is located in the second cavity, and the ASIC chip is attached to the outer surface of the inner shell.

Optionally, the inner shell is made of a metal material.

Optionally, the second region is provided with a copper foil, and the inner shell is fixed to the second region through the copper foil.

Optionally, the filter device includes at least one of a patch capacitor, a patch resistor, and a patch inductor.

Optionally, a receiving groove is dug in the second area, and the filter device is located in the receiving groove.

Optionally, the surface of the ASIC chip is coated with COB glue.

According to a second aspect of the present invention, there is provided an electronic device comprising the encapsulation structure of the first aspect.

According to one embodiment of the present disclosure, the ASIC chip and the filter device are stacked and integrally disposed in the second region of the circuit board, so that the occupied space of the second region on the circuit board is saved, and the overall package size of the microphone is reduced.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic structural diagram of a microphone in the prior art.

Fig. 2 is a schematic sectional view of a microphone in the prior art.

Fig. 3 is a schematic view of a packaging structure of a microphone according to the present application.

FIG. 4 is a schematic cross-sectional view of one embodiment of FIG. 3.

Fig. 5 is a schematic view of a packaging structure of a microphone according to the present application.

FIG. 6 is a schematic cross-sectional view of one embodiment of FIG. 5.

Fig. 7 is a schematic view of a circuit board provided with copper foil according to the present application.

Fig. 8 is a schematic cross-sectional structure view of another embodiment of fig. 3.

Description of reference numerals:

1-a housing; 11-a first cavity; 2-a circuit board; 21-a sound hole; 22-copper foil; 3-a MEMS chip; 4-an ASIC chip; 5-COB glue; 6-a filter device; 7-a support structure; 71-inner shell; 72-second cavity.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

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, further discussion thereof is not required in subsequent figures.

The circuit board of the microphone containing the filter circuit is usually designed to have a size large enough to accommodate the filter device 6, resulting in a large package size of the microphone as a whole, as shown in fig. 1.

In order to solve the problem of large package size, in the prior art, a sheet-shaped filter device 6 is embedded into the inner layer of the circuit board 2 by adopting a pressing process, as shown in fig. 2, but the filter device 6 embedded in this way has poor reliability, for example, a buried cavity, a buried short circuit and other adverse phenomena are easy to occur on a buried material.

In order to solve the above problems, the present invention provides a microphone package structure, as shown in fig. 3 to 8, including: the MEMS filter comprises a shell 1, a circuit board 2, an MEMS chip 3, an ASIC chip 4 and a filter device 6; the circuit board 2 comprises a first area and a second area, and the first area is provided with a sound hole 21 penetrating through the circuit board 2; the shell 1 and the circuit board 2 are covered to form a first cavity 11, the first area and the second area are located in the first cavity 11, and the first cavity 11 is communicated with the outside through the sound hole 21; the MEMS chip 3 is arranged in the first area and is opposite to the position of the sound hole 21; the ASIC chip 4 and the filter device 6 are arranged in the second area, the ASIC chip 4 is overlapped above the filter device 6, and the ASIC chip 4 is electrically connected with the MEMS chip 3.

Specifically, MEMS is a short term Micro electrical mechanical System, that is, a Micro Electromechanical System, and refers to a high-technology device with a size of several millimeters or less, and its internal structure is generally in the micrometer or even nanometer level, and is an independent intelligent System. The microphone in this embodiment is an MEMS microphone using the MEMS chip 3, and simply speaking, a capacitor is integrated on a micro silicon wafer, and can be manufactured by a surface mounting process, and the overall size is smaller than that of a conventional Electret Capacitor (ECM) microphone. In addition, the microphone is provided with an external bias by the ASIC chip 4, and the effective bias can ensure that the MEMS microphone can maintain stable acoustic and electric parameters in the whole operation temperature range. When the MEMS microphone works, the MEMS chip 3 can recognize external sound through the sound hole 21, and sound signals are converted into electric signals to be transmitted to the circuit board 2 for signal output through the processing of the ASIC chip 4. The filter device 6 of the scheme can form a filter circuit, and the anti-interference capability of the microphone is improved.

In the present embodiment, the region where the MEMS chip 3 and the sound hole 21 are provided is a first region, and the region where the ASIC chip 4 and the filter device 6 are provided is a second region. In order to reduce the size of the circuit board 2 as much as possible, the circuit board 2 may have only the above-described first and second regions, and a portion for interfacing with the housing 1. The ASIC chip 4 is arranged above the filter device 6 in an overlapping manner (see fig. 4, 6 and 8), so that the occupied space of the second area on the circuit board 2 is saved, the size of the circuit board 2 and the second area does not need to be increased for attaching the filter device 6 during product equipment, and the overall packaging size of the microphone is reduced. Wherein, ASIC chip 4 sets up both can be directly over in the top of filter 6, also can carry out corresponding dislocation set according to the spatial position relation, and ASIC chip 4 can directly be pasted on filter 6, also can set up on filter 6 through other modes, and specific form this application does not put the restriction.

Optionally, the filter device 6 is disposed on a surface of the second region, a support structure 7 is disposed on the filter device 6, and the ASIC chip 4 is attached to a surface of the support structure 7.

In particular, as shown in fig. 4 and 6, a support structure 7 may be disposed on the filter device 6, and the support structure 7 may protect the filter device 6 from damage or interference, on the one hand, and may also provide a mounting plane or a support surface for the ASIC chip 4, so that the ASIC chip 4 is easier to mount and more stable over the filter device 6. The shape, material, and position relation of the support structure 7 and the filter device 6 may be comprehensively set according to factors such as the actual type of the filter device 6 and the strength of the anti-interference capability, which is not limited in this application.

Optionally, the filter device 6 is embedded in the supporting structure 7, and the supporting structure 7 is made of an electronic packaging material.

Specifically, as shown in fig. 4, the electronic package material is a package structure diagram in which the filter device 6 is embedded in the support structure 7, and the electronic package material is a base material which is used for carrying electronic components and interconnection thereof, plays a role in mechanical support, sealing environmental protection, dissipating heat of the electronic components, and the like, has good electrical insulation, and is a sealing body of an integrated circuit. Electronic packaging materials such as some metals, glass, ceramics, or optoelectronic materials, etc. The application is not limited as to the type of electronic packaging material. Inlay filter 6 in the bearing structure 7 of making by electronic packaging material, can encapsulate it through traditional packaging technology such as moulding and realize, the structure after the encapsulation not only can provide sealed protection for filter 6, prevents that it from receiving external environment's interference, can also play insulating effect, prevents short circuit scheduling problem, has improved filter 6 and has shielded the reliability of disturbing. In addition, the surface of the filter device 6 after sealing is made more flat, so that the ASIC chip 4 can be mounted on the surface thereof more easily. In an embodiment, the ASIC chip 4 may be integrally packaged with the filter device 6, so as to simplify the packaging process and improve the assembly efficiency.

Optionally, the supporting structure 7 is an inner shell 71, the inner shell 71 and the second region cover to form a second cavity 72, the filter device 6 is located in the second cavity 72, and the ASIC chip 4 is attached to an outer surface of the inner shell 71.

Specifically, as shown in fig. 5 to 7, in this embodiment, the supporting structure 7 is an inner shell 71, the inner shell 71 is sleeved inside the outer shell 1, and a second cavity 72 formed by covering the inner shell with the second area can accommodate the filter device 6, so as to form better sealing protection for the filter device 6. The second cavity 72 is formed to prevent the filter device 6 and the support structure 7 (inner casing 71) from interfering with each other. The shape of the inner housing 71 can be designed according to actual requirements, for example, the inner housing 71 can be designed to be a flat square structure, the inner housing is buckled in the second area, the ASIC chip 4 is attached to the flat surface of the inner housing 71, a more stable supporting surface is provided, the ASIC chip 4 and the filter device 6 are separated from each other, and mutual interference is avoided.

Alternatively, the inner shell 71 is made of a metal material.

Specifically, on the basis of the above embodiment, the inner shell 71 may be made of a metal material, so that the inner shell 71 forms a metal cover capable of shielding an electric field, so that the inner shell 71 can shield external electromagnetic interference while providing protection for the filter device 6, and the entire filter circuit has a stronger anti-interference capability.

Optionally, the second area is provided with a copper foil 22, and the inner shell 71 is fixed to the second area through the copper foil 22.

Specifically, as shown in fig. 7, copper foil 22 is an anionic electrolytic material deposited as a thin, continuous metal foil on the base layer of circuit board 2 that readily adheres to the dielectric layer and receives a printed protective layer. After the copper foil 22 is used to fix the inner shell 71 to the second region, the bonding is stronger, so that the inner shell 71 is not easily detached. In addition, if the inner shell 71 is a metal shell, it is also convenient to ground the inner shell 71 to discharge the electric charge accumulated on the metal inner shell 71, thereby simplifying the installation of the circuit.

In the packaging process, the method can be performed according to the following steps:

s1: firstly, a filter device 6 is attached to a second area of the circuit board 2, and the filter device 6 can be communicated with the circuit board 2 to form a filter circuit; a layer of copper foil 22 is then deposited as required in the region around the filter device 6 (see figure 7);

s2, adhering the copper foil 22 attached to the inner shell 71 to a second area, wherein the inner shell 71 and the circuit board 2 form a second cavity 72, and the filter device 6 is positioned in the second cavity 72 (refer to FIG. 7);

s3: finally, the ASIC chip 4 is attached to the upper surface of the inner case 71, the MEMS chip 3 is attached to the first region, the ASIC chip 4 and the MEMS chip 3 are electrically connected, and the whole is packaged (see fig. 5).

Optionally, the filter device 6 includes at least one of a patch capacitor, a patch resistor, and a patch inductor.

Specifically, the filter device 6 may selectively set one or more of a patch capacitor, a patch resistor, and a patch inductor according to different requirements of the filter circuit, which is not limited in this application. The size of the surface mount electronic device is small, the surface mount technology can be used for packaging, the operation is simple, the packaging efficiency is high, the reliability of a surface mount capacitor, a surface mount resistor or a surface mount inductor is high, the problems of short circuit and the like of other devices are not easy to occur, and the reliability of the whole filter circuit can be improved.

Alternatively, as shown in fig. 8, a receiving groove is dug in the second region, and the filter device 6 is located in the receiving groove.

Specifically, the filter 6 that this embodiment adopted is less (for example, chip capacitor etc.) in size, directly digs on circuit board 2 and establishes the holding tank, places filter 6 in the holding tank, and filter 6 and circuit board 2's line intercommunication not only can reach the purpose of saving space like this, when adopting chip filter 6, has avoided easily taking place the emergence of bad phenomena such as the buried capacitor cavity, buried capacitor short circuit among the prior art moreover, and the reliability of its circuit is higher.

Alternatively, as shown in fig. 4, 6 and 8, the ASIC chip 4 is surface-coated with COB paste 5.

Specifically, the ASIC chip 4 is packaged over the filter device 6 by a Chip On Board (COB) process, i.e., the ASIC chip 4 is attached to the support structure 7 with a conductive or non-conductive adhesive and then wire-bonded to achieve electrical connection thereof. By adopting the mode, on one hand, the ASIC chip 4 can be prevented from being corroded by the external environment, the ASIC chip is better protected in a sealing way, the service life of the ASIC chip is prolonged, on the other hand, the ASIC chip can also play a role in shielding the external electromagnetic interference to a certain extent, and the anti-interference performance of the filter circuit is further enhanced.

According to a second aspect of the present invention, there is provided an electronic device including the packaging structure of the microphone according to the first aspect.

The embodiment provides an electronic device, which adopts the packaging structure of the microphone according to the first aspect of the present application, and by adopting the packaging structure of the microphone, the occupied space of the microphone in the electronic device can be smaller, more devices with other functions can be installed in the saved design space, or the overall structure of the electronic device can be reduced, and the structural performance of lightness and thinness can be achieved. The brain-carrying device can be a mobile phone, a tablet, an intelligent watch and the like, and the brain-carrying device is not limited in the application.

In the above embodiments, the differences between the embodiments are described in emphasis, and different optimization features between the embodiments can be combined to form a better embodiment as long as the differences are not contradictory, and further description is omitted here in consideration of brevity of the text.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A microphone package structure, comprising: the MEMS filter comprises a shell, a circuit board, an MEMS chip, an ASIC chip and a filter device;

2. The packaging structure of the microphone of claim 1, wherein the filter device is disposed on a surface of the second region, a support structure is disposed on the filter device, and the ASIC chip is attached to a surface of the support structure.

3. The microphone package structure of claim 2, wherein the filter device is embedded in the support structure, and the support structure is made of an electronic packaging material.

4. The microphone package structure of claim 2, wherein the supporting structure is an inner shell, the inner shell covers the second region to form a second cavity, the filter device is located in the second cavity, and the ASIC chip is attached to an outer surface of the inner shell.

5. The microphone package structure of claim 4, wherein the inner casing is made of a metal material.

6. The microphone package structure of claim 4, wherein the second region is provided with a copper foil, and the inner case is fixed to the second region by the copper foil.

7. The microphone package structure of claim 1, wherein the filter comprises at least one of a patch capacitor, a patch resistor, and a patch inductor.

8. The microphone package structure of claim 1, wherein the second region is hollowed to form a receiving groove, and the filter is located in the receiving groove.

9. The packaging structure of microphone according to claim 1, wherein the ASIC chip is surface-coated with COB glue.

10. An electronic device, characterized in that it comprises a package structure according to any one of claims 1 to 9.