CN102868965A - Method for producing micro-electromechanical systems (MEMS) microphone - Google Patents

Abstract

The invention provides a method for manufacturing a MEMS microphone. The method includes the following steps: providing a circuit board, a control circuit chip and a micro-electromechanical chip with a back cavity, and fixing the control circuit chip and the micro-electromechanical chip on the circuit board above; provide a metal shell with an inner wall, vapor-deposit an insulating layer on the inner wall of the shell; connect the shell cover evaporated with an insulating layer to the circuit board, so that the shell and the circuit board form a receiving cavity, and control the circuit chip and the micro The electromechanical chip is located in the accommodating cavity. The MEMS microphone provided by the invention can avoid the short-circuit phenomenon caused by the contact between the bound gold wire and the casing, thereby achieving the purpose of improving product performance.

Description

Manufacturing method of MEMS microphone

technical field

The invention relates to a microphone, in particular to a method for manufacturing a MEMS microphone.

Background technique

With the development of wireless communication, there are more and more mobile phone users around the world. The requirements of users for mobile phones are not only satisfied with calls, but also to be able to provide high-quality call effects. Especially the current development of mobile multimedia technology, the mobile phone Call quality is more important. The microphone of a mobile phone is used as a voice pick-up device for the mobile phone, and its design directly affects the call quality.

And the microphone that is currently used more and has better performance is a Micro-Electro-Mechanical-System Microphone (MEMS for short), and the microphone related to the present invention includes a circuit board, a control circuit chip placed on the circuit board and a circuit board. The micro-electromechanical chip, the housing connected with the circuit board cover to form a cavity, and the binding gold wire electrically connecting the control circuit chip and the micro-electromechanical chip, if the housing is made of conductive material, when the bottom or side of the housing is squeezed and deformed, It will cause the bonded gold wire to contact the shell and cause a short circuit, resulting in loss of microphone performance.

Therefore, it is necessary to provide a new MEMS microphone to solve the above problems.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for manufacturing a MEMS microphone that can improve product performance.

According to above-mentioned technical problem to be solved, a kind of manufacturing method of MEMS microphone has been designed, and this method comprises the steps:

(1) Provide a circuit board, a control circuit chip, and a micro-electromechanical chip with a back cavity, and fix the control circuit chip and the micro-electro-mechanical chip on the circuit board;

(2) Provide a metal shell with an inner wall, and evaporate an insulating layer on the inner wall of the shell;

(3) Connecting the casing cover evaporated with an insulating layer to the circuit board, so that the casing and the circuit board form a receiving cavity, and the control circuit chip and the micro-electromechanical chip are located in the receiving cavity.

Preferably, the insulating layer is high temperature resistant insulating varnish.

Preferably, in step (1), the micro-electromechanical chip and the control circuit chip, and the control circuit chip and the circuit board are respectively electrically connected by binding gold wires.

Preferably, in step (2), an acoustic hole is provided on the shell first, and the accommodation cavity communicates with the outside world through the acoustic hole.

Preferably, in step (2), acoustic holes are provided on the circuit board first, and the back cavity of the micro-electromechanical chip communicates with the outside world through the acoustic holes.

Preferably, in step (3), the insulating layer is located on a part of the inner wall of the housing.

The beneficial effect of the present invention is that: since the inner wall of the metal shell is vapor-deposited with a high-temperature-resistant insulating layer, when the product shell is deformed due to extrusion or collision, the insulating layer on the inner wall of the shell will insulate the bound gold wire from the shell. Therefore, the electroacoustic performance of the MEMS microphone will not be affected, and the purpose of improving product performance is finally achieved.

Description of drawings

FIG. 1 is a cross-sectional view of the MEMS microphone of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

With reference to shown in Figure 1, for the MEMS microphone 100 that the present invention provides, its manufacturing method comprises the following steps:

(1) Provide a circuit board 20, a control circuit chip 32, and a micro-electromechanical chip 31 provided with a back cavity 310, fix the control circuit chip 32 and the micro-electromechanical chip 31 on the circuit board 20, and place the micro-electromechanical chip 31 respectively and the control circuit chip 32, the control circuit chip 32 and the circuit board 20 are electrically connected by binding gold wires 40;

(2) Provide a casing 10 with an inner wall 11, the casing 10 is made of metal material, and an insulating layer 60 is vapor-deposited on the inner wall 11 of the casing 10. In this embodiment, the insulating layer 60 can be a high temperature resistant insulating layer Paint, in other embodiments, can also be other materials with high temperature resistance;

(3) Cover the housing 10 with the insulating layer 60 evaporated on the circuit board 20, so that the housing 10 and the circuit board 20 form a housing chamber 50, and the control circuit chip 32 and the micro-electromechanical chip 31 are located in the housing chamber 50 , the circuit board 20 is fixedly connected to the housing 10 through an adhesive substance, such as glue or solder paste.

In step (2), the shell 10 is first provided with a sound hole 12, and the receiving cavity 50 communicates with the outside world through the sound hole 12; in other embodiments, in step (1), a sound hole can be set on the circuit board, The back cavity of the MEMS chip communicates with the outside world through the sound hole.

In addition, the insulating layer 60 is located on part of the inner wall 11 of the casing 10, that is, the insulating layer 60 is not provided at the junction of the casing 10 and the circuit board 20, so as to prevent the insulating layer 60 from reacting with glue or other adhesive substances, thus affecting the insulation. Layer 60 properties.

Since the high-temperature-resistant insulating layer 60 is evaporated on the inner wall 11 of the metal shell 10, when the product shell is deformed due to extrusion or collision, the insulating layer 60 on the inner wall 11 of the shell will insulate the gold wire 40 from the shell 10, so that The various electroacoustic properties of the MEMS microphone are almost unchanged, and the purpose of improving product performance is finally achieved. In addition, the use of the vapor-deposited insulating layer 60 can also save internal space, expand the sound cavity, and the manufacturing process is simple.

The protection scope of the present invention is not limited to the above-mentioned embodiments, but all equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention shall be included in the protection scope described in the claims.

Claims (6)

1. a manufacturing method of MEMS microphone, is characterized in that, the method comprises the steps: (1) Provide a circuit board, a control circuit chip, and a micro-electromechanical chip with a back cavity, and fix the control circuit chip and the micro-electro-mechanical chip on the circuit board; (2) Provide a metal shell with an inner wall, and evaporate an insulating layer on the inner wall of the shell; (3) Connecting the casing cover evaporated with an insulating layer to the circuit board, so that the casing and the circuit board form a receiving cavity, and the control circuit chip and the micro-electromechanical chip are located in the receiving cavity. 2. The manufacturing method of the MEMS microphone according to claim 1, characterized in that: the insulating layer is a high temperature resistant insulating varnish. 3. The manufacturing method of the MEMS microphone according to claim 1, characterized in that: in step (1), the micro-electromechanical chip and the control circuit chip, and the control circuit chip and the circuit board are electrically connected by binding gold wires. 4 . The manufacturing method of the MEMS microphone according to claim 1 , characterized in that: in step (2), a sound hole is provided on the shell first, and the receiving cavity communicates with the outside world through the sound hole. 5 . 5 . The manufacturing method of the MEMS microphone according to claim 1 , characterized in that: in step (2), the circuit board is first provided with sound holes, and the back cavity of the micro-electromechanical chip communicates with the outside through the sound holes. 6 . 6. The manufacturing method of the MEMS microphone according to claim 1, characterized in that: in step (3), the insulating layer is located on a part of the inner wall of the housing.

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