WO2012122868A1

WO2012122868A1 - Micro-electro-mechanical system microphone packaging structure and forming method therefor

Info

Publication number: WO2012122868A1
Application number: PCT/CN2012/071433
Authority: WO
Inventors: 柳连俊
Original assignee: 迈尔森电子（天津）有限公司
Priority date: 2011-03-15
Filing date: 2012-02-22
Publication date: 2012-09-20
Also published as: CN102158775B; CN102158775A

Abstract

A micro-electro-mechanical system (MEMS) microphone packaging structure and a forming method therefor. The MEMS microphone packaging structure comprises: a microphone component, the microphone component comprises a first surface, a second surface opposite the first surface, and a third surface connected to the first surface and to the second surface, a packaging substrate, the packaging substrate is for use in bearing the microphone component, and the packaging substrate is opposite to the second surface of the microphone component, and a packaging layer, the packaging layer covers at least the third surface of the microphone component, and a sound inlet, the sound inlet transmits a sound signal to the microphone component. Employment of the MEMS microphone packaging structure and the forming method therefor provided in the present invention allows for reduced manufacturing costs of the MEMS microphone packaging structure, and for improved manufacturing efficiency.

Description

Microelectromechanical system microphone package structure and forming method thereof

This application claims priority to Chinese Patent Application No. 201110061469.2, entitled "Micro-Electro-Mechanical System Microphone Encapsulation Structure and Method of Forming the Same", filed on March 15, 2011, the entire contents of In this application. Technical field

The present invention relates to a microphone package structure and a method of forming the same, and more particularly to a MEMS microphone package structure and a method of forming the same.

Background technique

Due to the increasing demand for mobile phones and the increasing demand for sound quality in mobile phones, coupled with the maturity of hearing aid technology, these factors have led to a rapid increase in demand for high-quality miniature microphones. Due to the advantages of light weight, small size and good signal quality, the MEMS microphone has become the mainstream of microphones and is widely used in applications such as MEMS (Micro-Electro-Mechanical System) technology. In the communication tool of the mobile phone.

MEMS technology refers to the technology of designing, processing, manufacturing, measuring and controlling micro/nano materials. Various sensors can be fabricated using MEMS technology, such as inertial sensors or capacitive pressure sensors.

The US Patent Publication No. US6781231 discloses a "Micro-Electro-Mechanical System Package Structure with Environmental and Interference Protection". As shown in FIG. 1, the MEMS package structure has a MEMS microphone 31, a substrate 21 and a cover 11. The substrate 21 has at least one surface for carrying the MEMS microphone 31; the cover 11 is divided into a central portion and a peripheral portion surrounding the central portion; by connecting the peripheral portion of the cover 11 to the substrate 21, the cover 11 and The substrate 21 forms a casing, and a central portion of the cover 11 is spaced apart from the substrate 21 by a space 41 to accommodate the MEMS microphone. The housing has sound holes to allow sound signals to reach the MEMS microphone 31.

However, for the existing electromechanical system package structure, since the housing has a space 41 for accommodating the MEMS microphone, that is, a large space between the MEMS microphone 31 and the cover 11, the MEMS package structure is relatively large, and It is not conducive to the protection of the MEMS microphone; in addition, the material of the cover 11 is selected from a metal material, so the weight of the MEMS package structure is relatively large; On the other hand, in the method for forming a conventional MEMS package structure, the cover 11 needs to be connected to the substrate 21 one by one to form a case, so that the package efficiency is relatively low.

Summary of the invention

The problem to be solved by the present invention is to provide a MEMS microphone package structure and a method for forming the same, to reduce the volume of the MEMS microphone package structure and improve the protection effect on the MEMS microphone.

To achieve the above objective, embodiments of the present invention provide a MEMS microphone package structure, including:

a microphone assembly, the microphone assembly including a first surface, a second surface opposite the first surface, and a third surface connecting the first surface and the second surface;

a package substrate, the package substrate carrying the microphone assembly and opposite to a second surface of the microphone assembly;

An encapsulation layer, the encapsulation layer covering at least a third surface of the microphone assembly;

The sound is inserted into the hole, and the sound entry hole transmits a sound signal to the microphone assembly.

Optionally, the microphone assembly includes a first electrode, a second electrode, a first opening exposing the first electrode, and a second opening exposing the second electrode.

Optionally, the sound inlet hole is located in the package substrate and communicates with the second opening.

Optionally, the encapsulation layer further covers a first surface of the microphone component, the encapsulation layer includes a third opening, and the third opening is in communication with the first opening.

Optionally, the MEMS microphone package structure further includes a package cover covering the package layer, the package cover is disposed opposite to the package substrate, and the package cover and the first opening and the third opening enclose an acoustic cavity.

Optionally, the third opening has a first side away from the package substrate and a second side adjacent to the package substrate in a section perpendicular to the direction of the package substrate, the length of the first side being greater than the second The length of the side.

Optionally, the MEMS microphone package structure further includes a package cover covering the package layer, the package cover is disposed opposite to the package substrate, and the package cover and the first opening enclose an acoustic cavity.

Optionally, the material of the package cover is plastic.

Optionally, the encapsulation layer further covers a first surface of the microphone component, the encapsulation layer includes a third opening, the third opening is in communication with the first opening, and the sound inlet hole is the Three openings. Optionally, the sound inlet hole is the first opening.

Optionally, the package substrate and the second opening enclose an acoustic cavity.

Optionally, an interposer is further disposed between the package substrate and the microphone component, the interposer has a fourth opening, the fourth opening is in communication with the second opening, and the package substrate and the first The second opening and the fourth opening enclose an acoustic cavity.

Optionally, the fourth opening has a third side away from the package substrate and a fourth side adjacent to the package substrate in a cross section perpendicular to the direction of the package substrate, the third side having a length smaller than the fourth The length of the side.

Optionally, the microphone assembly further includes a lead wire electrically connected to one end of the pressure welding plate of the microphone assembly, and the other end is electrically connected to the package substrate for converting the sound signal The resulting electrical signal leads to the microphone assembly.

Optionally, the package substrate is a lead frame or a printed circuit board.

Optionally, the encapsulation layer includes a buffer layer that abuts the third surface of the microphone assembly.

Optionally, the material of the buffer layer is a soft glue.

Optionally, the material of the encapsulation layer comprises plastic.

Optionally, the microphone assembly comprises: a MEMS microphone, a signal processing circuit, an inertial sensor or/and a pressure sensor integrated with the MEMS microphone.

Correspondingly, the embodiment of the present invention further provides a method for forming a MEMS microphone package structure, which includes:

Providing a microphone assembly, the microphone assembly including a first surface, a second surface opposite the first surface, and a third surface connecting the first surface and the second surface;

Providing a package substrate, the package substrate for carrying the microphone assembly;

Combining the microphone assembly and the package substrate, the package substrate is opposite to a second surface of the microphone assembly;

An encapsulation layer covering at least a third surface of the microphone assembly is formed.

Optionally, the method further includes: forming, in the package substrate, a sound inlet hole for introducing a sound signal into the microphone component, wherein the sound inlet hole communicates with the second opening. Optionally, the method further includes: forming a package cover covering the package layer, the package cover being disposed opposite to the package substrate.

Optionally, the encapsulation cover material is plastic.

Optionally, the encapsulation layer further covers a first surface of the microphone component, and the method for forming the MEMS microphone package structure further includes: forming a third opening in the encapsulation layer covering the first surface of the microphone component The third opening is in communication with the first opening.

Optionally, the third opening has a first side away from the package substrate and a second side adjacent to the package substrate in a cross section perpendicular to the direction of the package substrate, the first side having a length smaller than the second The length of the side.

Optionally, the encapsulation layer further covers a first surface of the microphone component, and the method for forming the MEMS microphone package structure further includes: forming a third opening in the encapsulation layer covering the first surface of the microphone component The third opening is in communication with the first opening, and the third opening is a sound inlet hole for introducing a sound signal into the microphone assembly.

Optionally, the first opening is a sound inlet hole for introducing a sound signal into the microphone assembly.

Optionally, combining the microphone component with the package substrate includes:

Forming an interposer having a fourth opening on the second surface of the microphone assembly, the fourth opening being in communication with the second opening;

The interposer and package substrate are combined.

Optionally, the encapsulation layer is formed using a die package.

Optionally, the step of forming the encapsulation layer further comprises forming a buffer layer on the third surface of the microphone assembly.

Optionally, the material of the filling package is plastic.

Optionally, the step of performing a mold encapsulation includes forming a mold that covers the first opening of the microphone assembly. Compared with the prior art, the above technical solution has the following advantages:

The encapsulation layer covers the surface of the microphone component, so it is advantageous to reduce the volume of the MEMS microphone package structure and to improve the protection effect on the microphone component; The encapsulation layer is made of plastic, which can reduce the weight of the MEMS microphone package structure. In an optional embodiment of the invention, the encapsulation layer further includes a buffer layer, so that the protection effect on the microphone component can be further improved;

The method for forming a MEMS microphone package structure provided by the embodiment of the present invention can simultaneously package a plurality of microphone components on the same wafer, that is, an encapsulation layer covering a plurality of microphone components can be simultaneously formed, thereby simplifying the packaging process. , efficient.

DRAWINGS

1 is a schematic view of a conventional MEMS packaging structure;

2 and 3 are schematic views of a MEMS microphone package structure according to a first embodiment of the present invention;

4 and 5 are schematic views of a MEMS microphone package structure according to a second embodiment of the present invention;

6 is a schematic diagram of a MEMS microphone package structure according to a third embodiment of the present invention; FIG. 7 is a schematic diagram of a MEMS microphone package structure according to a fourth embodiment of the present invention; FIGS. 8 and 9 are fifth embodiment of the present invention. A schematic diagram of a MEMS microphone package structure provided;

10 is a schematic flow chart of a method for forming a MEMS microphone package structure provided in FIG. 2; FIG. 11 to FIG. 16 are schematic cross-sectional views showing a method of forming a MEMS microphone package structure provided in FIG.

17 is a schematic flow chart of a method for forming a MEMS microphone package structure according to a third embodiment of the present invention;

18 and 19 are cross-sectional views showing a method of forming a MEMS microphone package structure according to a third embodiment of the present invention.

detailed description

According to the background art, MEMS microphones have gradually become the mainstream of microphones, but existing

The MEMS microphone package is bulky and costly. The inventor has studied the above problems, and provides a MEMS microphone package structure in the embodiment of the present invention. The MEMS microphone package structure provided by the embodiment of the present invention includes:

a microphone assembly, the microphone assembly including a first surface, a second opposite the first surface a surface, and a third surface connecting the first surface and the second surface;

a package substrate, the package substrate carrying the microphone assembly, and the package substrate being opposite to a second surface of the microphone assembly;

Accordingly, the present invention also provides a method of forming the above MEMS microphone package structure, comprising: providing a microphone assembly, the microphone assembly including a first surface, a second surface opposite the first surface, and connecting the first surface And a third surface of the second surface;

In the MEMS microphone package structure formed by the embodiment of the present invention, the encapsulation layer covers the microphone component, so that the volume of the MEMS microphone package structure is reduced, and the protection effect on the microphone component is improved;

In addition, the encapsulation layer is made of plastic, which can reduce the weight of the MEMS microphone package structure. In an optional embodiment of the invention, the encapsulation layer further includes a buffer layer, so that the protection effect on the microphone component can be further improved;

The method for forming a MEMS microphone package structure provided by the embodiments of the present invention can simultaneously package a plurality of microphone components on the same wafer, that is, an encapsulation layer covering a plurality of microphone components can be simultaneously formed, so that the packaging process is simple. efficient.

The embodiments of the present invention are further described below in conjunction with the accompanying drawings and embodiments.

First embodiment

2 is a schematic diagram of a MEMS microphone package structure according to a first embodiment of the present invention. Referring to FIG. 2, the MEMS microphone package structure provided in this embodiment includes:

a microphone assembly 130, the microphone assembly 130 includes a first surface 10, a second surface 20 opposite the first surface 10, and a third surface 30 connecting the first surface 10 and the second surface 20; In an embodiment of the invention, the first surface 10 is an upper surface of the microphone assembly 130, the second surface 20 is a lower surface of the microphone assembly 130, and the third surface 30 is an outer surface of the microphone assembly 130.

a package substrate 100, the package substrate 100 carrying the microphone assembly 130, and the package substrate 100 is opposite to the second surface 20 of the microphone assembly 130;

The encapsulation layer 103 covers the third surface 30 and the first surface 10 of the microphone assembly 130. The encapsulation layer covering the first surface does not completely cover the first surface, and the encapsulation layer on the first surface The third opening 140 is connected to the first opening;

The sound entry aperture 108 transmits the acoustic signal to the microphone assembly 130.

In this embodiment, the microphone assembly 130 includes a first electrode 115 and a second electrode 120, and further includes a first opening 150 exposing the first electrode 115 and a second opening 160 exposing the second electrode 120. The sound inlet hole 108 is located in the package substrate 100 and is in communication with the second opening 160.

In the present embodiment, the microphone assembly 130 is bonded to the package substrate 100 by the die attach adhesive 106. The package substrate 100 is a lead frame or a printed circuit board.

The lead frame refers to a thin metal plate serving as a lead inside the integrated block, which functions as a bridge connected to the external wires.

A printed circuit board (PCB) is a substrate that is cut into a certain size and has at least one conductive pattern attached thereto, and is provided with holes (such as component holes and fastening holes). , metallized holes, etc.), used to replace the chassis of the electronic components of the previous device, and to achieve interconnection between electronic components.

In the embodiment where the printed circuit board is printed on the package substrate, an LGA package (Land Grid Array) can be used: The LGA package is an important package form without solder balls, which can be directly mounted on the printed circuit board. It is widely used in microprocessors and other high-end chip packages.

In an alternative embodiment of the present invention, the MEMS microphone package structure further includes a lead 102. In the embodiment, the lead 102 is located in the encapsulation layer 103, and the lead 102 is disposed at the end of the microphone assembly 130. The pressure bonding plate 40 is electrically connected, and the other end is electrically connected to the package substrate 100 for guiding an electrical signal converted from the sound signal out of the microphone assembly 130.

The package substrate 100 further includes a solder-bonded pin 101 electrically connected to the bonding pad 40 of the microphone assembly 130 and the bonding pad 101 of the package substrate 100, which is generated by the microphone assembly 130. The electrical signal is transmitted out of the microphone assembly 130 through the pressure plate sheet 40 and the pressure welding pin 101.

In other embodiments of the invention, the electrical signals generated by the microphone assembly 130 may also be transmitted out of the microphone assembly 130 by wires 102 without other means known to those skilled in the art.

In this embodiment, the encapsulation layer 103 covers a portion of the first surface 10 and all of the third surface 30 of the microphone assembly 130. The encapsulation layer 103 further includes a third opening 140, the third opening 140 and the microphone assembly. The first opening 150 of the 130 is in communication. The material of the encapsulation layer 103 is plastic.

The MEMS microphone package structure further includes a package cover 107 disposed opposite the package substrate 100, and the package cover 107 and the package layer 103 are bonded by an adhesive. The package cover 107 and the first opening 150 and the third opening 140 enclose an acoustic cavity, which may cause the first electrode 115 to vibrate in the acoustic cavity and the microphone assembly 130 when the acoustic signal enters the MEMS microphone package structure.

After the package cover 107 is bonded to the encapsulation layer 103 having the third opening 140, the third opening 140, the first opening 150 and the package cover 107 constitute an acoustic cavity, thereby increasing the volume of the acoustic cavity and improving the sensitivity of the MEMS microphone.

In this embodiment, the third opening 140 has a first side away from the package substrate 100 and a second side adjacent to the package substrate 100 in a cross section perpendicular to the direction of the package substrate 100, the first side The length is greater than the length of the second side. The large and small shape of the third opening 140 facilitates the storage of the sound signal. In an alternative of the embodiment, the shape of the cross section of the third opening 140 in a direction perpendicular to the package substrate 100 is an inverted trapezoid.

In other embodiments, the encapsulation layer 103 may also cover only the third surface 30 of the microphone assembly 130, the encapsulation cover 107 being bonded to the first surface 10 of the microphone assembly by an adhesive. The package cover and the first opening 150 enclose an acoustic cavity, which causes vibration of the first electrode 115 in the acoustic cavity and the microphone assembly 130 when the acoustic signal enters the MEMS microphone package structure. The MEMS microphone package structure provided by this embodiment is smaller in size.

In an alternate embodiment of the invention, the microphone assembly 130 includes an electromechanical system microphone 105 and a signal processing circuit 104. The electromechanical system microphone 105 and the signal processing circuit 104 are bonded together in a metal or metal alloy to form the microphone assembly 130. One of the advantages of the MEMS microphone 105 is its relatively small size.

In other optional embodiments of the present invention, the microphone assembly 130 includes: an electromechanical system microphone 105, a signal processing circuit 104, and other passes integrated with the MEMS microphone 105. A sensor, such as an inertial sensor (not shown) and a pressure sensor (not shown), and the like.

In an alternative embodiment of the invention, the material of the package cover 107 is plastic, metal or other material, optionally plastic. Forming the package cover 107 with plastic is simple in process, low in cost, and the package cover 107 is relatively small in weight and convenient to carry.

In an alternative embodiment of the present invention, the encapsulation layer 103 is attached to the microphone assembly 130 to facilitate reducing the volume of the MEMS microphone package structure and to protect the microphone assembly 130; forming the package using plastic The layer 103 has a simple process and low cost, and the formed encapsulation layer 103 has a relatively small weight and is convenient to carry.

As shown in FIG. 3, in an alternative embodiment of the present embodiment, the encapsulation layer 103 is a stacked structure, and further includes a buffer layer 50 formed on the third surface 30 of the microphone assembly 130. The material of the buffer layer 50 is a soft rubber. The material of the portion other than the buffer layer of the encapsulation layer 103 is plastic, that is, the material of the encapsulation layer 103 includes plastic and soft rubber (buffer layer). The encapsulation layer 103 is formed directly on the third surface 30 of the microphone assembly 130. Since the thermal expansion coefficient of the material of the encapsulation layer 103 is relatively large, the stress between the microphone assembly 130 and the encapsulation layer 103 is relatively large, under the condition of being heated or stressed. The damage of the encapsulation layer 103 or the microphone assembly 130 is easily caused. The buffer layer 50 can reduce the stress between the microphone assembly 130 and the encapsulation layer 103, and protect the microphone assembly 130 and the encapsulation layer 103.

In the embodiment, the sound inlet hole 108 is located in the package substrate 100, and the sound input hole 108 transmits a sound signal to the microphone assembly 130, and enters the first electrode 115 and the second electrode 120 via the second opening 160, causing The first electrode 115 vibrates within the formed acoustic cavity and microphone assembly 130 and converts the acoustic signal into an electrical signal that is led out of the microphone assembly 130 via lead 102.

In other embodiments of the invention, the microphone assembly 130 may have other configurations. A flow chart of a method for forming a MEMS microphone package structure shown in FIG. 2 is shown in FIG. 10, which includes:

Step S101, providing a microphone assembly 130, the microphone assembly 130 including a first surface 10, a second surface 20 opposite the first surface 10, and a third surface connecting the first surface 10 and the second surface 20 30;

Referring to FIG. 11 , in the embodiment of the present invention, the first surface 10 is an upper surface of the microphone assembly 130 , the second surface 20 is a lower surface of the microphone assembly 130 , and the third surface 30 is an outer surface of the microphone assembly 130 . The microphone assembly 130 includes a first electrode 115 and a second electrode 120, A first opening 150 penetrating the first surface 10 and exposing the first electrode 115, and a second opening 160 extending through the second surface 20 and exposing the second electrode 120 are included.

In an alternate embodiment of the invention, the microphone assembly 130 includes an electromechanical system microphone 105 and a signal processing circuit 104. The MEMS microphone 105 and the signal processing circuit 104 are bonded together in a metal or metal alloy to form the microphone assembly 130.

In other optional embodiments of the present invention, the microphone assembly further includes: integrating other sensors, such as an inertial sensor and a pressure sensor, with the electromechanical system microphone 105.

Step S102, providing a package substrate 100 for carrying the microphone assembly 130.

In an embodiment of the present invention, the sound in hole 108 may be formed in the package substrate 100 first, and in the subsequent step of combining the microphone assembly 130 and the package substrate 100, the sound entrance hole 108 may be aligned. And a second opening 160 of the microphone assembly 130; or after bonding the microphone assembly 130 and the package substrate 100, the package substrate 100 corresponds to the second opening 160 of the microphone assembly 130 The portion forms a sound entrance hole 108, and the formation process of the sound entrance hole 108 can be formed by a process known to those skilled in the art, and it is required to ensure that the formed sound entrance hole 108 and the second opening 160 of the microphone assembly 130 are formed. The same.

The package substrate 100 also includes a bond pad 101.

Step S103, in combination with the microphone assembly 130 and the package substrate 100, the package substrate 100 is opposite to the second surface 20 of the microphone assembly 130.

Referring to FIG. 12, the package substrate 100 and the microphone assembly 130 are bonded by a die attach adhesive 106, and the sound in hole 108 and the second opening 160 are aligned.

Referring to Figure 13, in an alternative embodiment of the invention, the acoustic signals generated by the microphone assembly 130 are transmitted out of the MEMS microphone package structure via leads 102. Specifically, the microphone assembly includes a pressure-welded plate piece 40, the lead end 102 is electrically connected to the pressure-welded plate piece 40 of the microphone assembly, and the other end is electrically connected to the pressure-welded pin 101 of the package substrate 100. An electrical signal for converting the sound signal into the microphone assembly 130 is taken out of the microphone assembly 130.

In other embodiments of the invention, electrical signals generated by the microphone assembly 130 may also be transmitted out of the microphone assembly 130 by wires, other than those well known to those skilled in the art.

Step S104, forming a third surface 30 and the first surface 10 covering the microphone assembly 130 Encapsulation layer 103.

Referring to Figures 14 and 15, together, a first surface 10 mold 200 covering the microphone assembly 130 is formed to prevent the plastic from filling the first opening 150 of the microphone assembly 130.

Then plastic is used for filling and encapsulation. The mold 200 is then removed.

In an alternative embodiment of the invention, the length of the formed mold along the A-A line that is away from the side of the package substrate 100 is greater than the length of the side adjacent the package substrate 100. As shown in FIG. 14, in one embodiment, the formed mold has an inverted trapezoidal shape along the AA line, thereby forming an encapsulation layer 103 including a third opening 140 as shown in FIG. The first surface 10 and the third surface 30 of the microphone assembly 130. In other embodiments of the invention, the formed mold has a rectangular cross-section along the A-A line, and the formed encapsulation layer covers only the third surface 30 of the microphone assembly 130.

Step S105, providing a package cover 107, the package cover 107 being disposed opposite to the package substrate 100. Referring to FIG. 16, the package cover 107 and the encapsulation layer 103 are bonded by an adhesive 206. In this embodiment, the material of the package cover 107 is plastic.

At this time, the package cover 107 and the third opening 140, the first opening 150 encloses an acoustic cavity. The third opening 140 formed in the encapsulation layer 103 can increase the space of the formed acoustic cavity, thereby improving the MEMS microphone sensitivity. Specifically, the encapsulation layer 103 is related to the shape of the mold. In other embodiments of the invention, the shape of the mold can be designed according to the needs of the process, and the scope of protection of the embodiments of the invention should not be limited by the shape of the mold. In the case where the encapsulation layer 103 covers only the third surface 30, the acoustic cavity is surrounded by the encapsulation cover 107 and the first opening 150.

In this embodiment, the encapsulation layer 103 is formed by a method of filling and packaging. Therefore, a plurality of microphone components to be packaged can be molded and packaged at the same time, and then separated to form an independent microphone package structure. Compared with the existing package, the method of packaging by metal material is not only the entire package structure is small, but also can package multiple microphone components in the same batch, the packaging process is simple, the cost is low, especially the package. The efficiency is high.

The difference between the method of forming the MEMS microphone package structure shown in FIG. 3 and the method of forming the MEMS microphone package structure shown in FIG. 2 is as follows:

In the method for forming the MEMS microphone package structure shown in FIG. 3, before the mold assembly of the microphone assembly 130, the buffer assembly is further formed on the third surface 30 of the microphone assembly 130, and the material of the buffer layer is Soft gel. If a single layer is formed directly on the third surface 30 of the microphone assembly 130 The encapsulation layer 103, because the material of the encapsulation layer 103 of the single layer is generally selected from a material having a relatively large thermal expansion coefficient, such as plastic, the stress between the microphone assembly 130 and the surrounding encapsulation layer 103 is relatively large, and is subjected to heat or stress. In this case, damage to the encapsulation layer 103 or the microphone assembly 130 is easily caused, and the buffer layer can reduce the stress between the microphone assembly 130 and the encapsulation layer 103, and protect the microphone assembly 130 and the encapsulation layer 103.

In the MEMS microphone package structure formed in this embodiment, the encapsulation layer covers the surface of the microphone component, so that the volume of the MEMS microphone package structure is reduced, and the protection effect on the microphone component is improved;

In addition, the package layer of the MEMS microphone package structure provided by the embodiment of the present invention adopts plastic material, which can reduce the weight of the MEMS microphone package structure;

Moreover, the method for forming a MEMS microphone package structure provided by the embodiments of the present invention has a simple process and high efficiency.

Further, in this embodiment, the encapsulation layer further includes a buffer layer, so that the protection effect on the microphone component can be further improved.

Second embodiment

4 and FIG. 5 are schematic diagrams showing a MEMS microphone package structure according to a second embodiment of the present invention. The main difference between this embodiment and the first embodiment is that, in this embodiment, the sound entrance hole is opposite to the package substrate. And communicating with the first opening, and in the first embodiment, the sound inlet hole is located in the package substrate and communicates with the second opening.

Referring to FIG. 4 and FIG. 5 , the MEMS microphone package structure provided in this embodiment includes: a microphone assembly 130 including a first surface 10 , a second surface 20 opposite to the first surface 10 , and Connecting the third surface 30 of the first surface 10 and the second surface 20;

a package substrate 300, the package substrate 300 carrying the microphone assembly 130, and the package substrate 300 is opposite to the second surface 20 of the microphone assembly 130;

The encapsulation layer 103 covers the third surface 30 of the microphone assembly 130 or covers the first surface 10 and the third surface 30 at the same time; the encapsulation layer covering the first surface 10 does not completely cover the first surface, Included in the encapsulation layer on the first surface is a third opening that communicates with the first opening The sound is inserted into the hole, and the sound inlet hole communicates with the first opening 150 to transmit a sound signal to the microphone assembly 130.

In this embodiment, the microphone assembly includes a first electrode 115 and a second electrode 120, and further includes a first opening 150 exposing the first electrode 115 and a second opening 160 exposing the second electrode 120.

Referring to FIG. 4 , in the embodiment, the encapsulation layer 103 covers the first surface 10 and the third surface 30 of the microphone assembly 130 , and the encapsulation layer 103 further includes a third opening 140 , the third opening 140 is in communication with the first opening 150 of the microphone assembly 130. The third opening 140 constitutes a sound entrance hole of the MEMS microphone package structure provided by the embodiment. In the present embodiment, sound enters the microphone assembly 130 from the sound entrance hole (i.e., the third opening 140), and then reaches the first electrode 115 and the second electrode 120 via the first opening 150.

In this embodiment, the cross section of the third opening 140 in a direction perpendicular to the package substrate 300 includes a first side away from the package substrate 300 and a second side adjacent to the package substrate 300, the first side The length is greater than the length of the second side. The large and small shape of the third opening 140 facilitates the storage of the sound signal, thereby increasing the sensitivity of the microphone. In an alternative of the embodiment, the shape of the cross section of the third opening 140 in a direction perpendicular to the package substrate 300 is an inverted trapezoid.

In an alternative embodiment of the present invention, the MEMS microphone package structure further includes a lead 102. In the embodiment, the lead 102 is located in the encapsulation layer 103, and the lead 102 is disposed at the end of the microphone assembly 130. The bonding pad 40 is electrically connected, and the other end is electrically connected to the package substrate 300 for taking an electrical signal converted from the sound signal out of the microphone assembly 130.

The package substrate 300 further includes a bonding pin 101 electrically connected to the microphone assembly

The bonding pad 40 of the 130 and the bonding pin 101 of the package substrate 300 pass the electrical signals generated in the microphone assembly 130 out of the microphone assembly 130 through the bonding pad 40 and the bonding pins 101.

In this embodiment, the second opening 160 and the package substrate 300 enclose an acoustic cavity.

In an alternative embodiment of the invention, the material of the encapsulation layer 103 is plastic. Forming the encapsulation layer 103 with plastic is simple in process, low in cost, and the formed encapsulation layer 103 has a relatively small weight and is convenient to carry.

In the present embodiment, the microphone assembly includes an electromechanical system microphone 105 and a signal processing circuit 104. The MEMS microphone 105 and the signal processing circuit 104 are bonded together in a metal or metal alloy to form the microphone assembly 130. One of the advantages of the MEMS microphone 105 is its volume ratio Smaller.

In an alternative embodiment of the present embodiment, the encapsulation layer 103 is a stacked structure and further includes a buffer layer that is attached to the third surface 130 of the microphone assembly 130. The material of the buffer layer is a soft gel. The material of the portion of the encapsulation layer 103 other than the buffer layer is plastic, that is, the material of the encapsulation layer 103 includes plastic and soft rubber (buffer layer). The encapsulation layer 103 having a relatively large thermal expansion coefficient is formed directly on the third surface 30 of the microphone assembly 130. The stress between the microphone assembly 130 and the encapsulation layer 103 is relatively large, and in the case of being heated or stressed, it is easy to cause the encapsulation layer 103 or In the damage of the microphone assembly 130, the buffer layer can reduce the stress between the microphone assembly 130 and the encapsulation layer 103, and form protection for the microphone assembly 130 and the encapsulation layer 103.

In the present embodiment, sound enters the microphone assembly 130 through the sound inlet hole, enters the first electrode 115 and the second electrode 120 via the first opening 150, causing the first electrode 115 to be within the formed acoustic cavity and microphone assembly 130. Vibrating, and converting the acoustic signal into an electrical signal, leads the microphone assembly 130 via lead 102.

As shown in FIG. 5, in another embodiment of the present invention, the encapsulation layer 103 may cover only the third surface 30 of the microphone assembly 130. The first opening 150 of the microphone assembly 130 constitutes a sound inlet hole, FIG. In the illustrated embodiment, the volume of the package structure formed is less than that shown in FIG.

The encapsulation layer of the MEMS microphone package structure provided by the embodiment of the present invention covers the surface of the microphone component, so that the volume of the MEMS microphone package structure is reduced, and the protection effect on the microphone component is improved;

The encapsulation layer is made of plastic, which can reduce the weight of the MEMS microphone package structure. In an optional embodiment of the invention, the encapsulation layer further includes a buffer layer, so that the protection effect on the microphone assembly can be further improved.

Correspondingly, the present invention also provides a method for forming a MEMS microphone package structure provided by the second embodiment. The method for forming the MEMS microphone package structure provided in FIG. 4 includes:

A microphone assembly 130 is provided, the microphone assembly 130 including a first surface 10, a second surface 20 opposite the first surface 10, and a third surface 30 connecting the first surface 10 and the second surface 20;

Providing a package substrate 300 for carrying the microphone assembly 130; combining the microphone assembly 130 with the package substrate 300, the package substrate 300 and a microphone The second surface 20 of the wind assembly 130 is opposite;

Forming an encapsulation layer 103 covering the third surface 30 and the first surface 10 of the microphone assembly 130, and forming a third opening in the encapsulation layer 103 covering the first surface of the microphone assembly 130, the third opening 140 and The first opening 150 of the microphone assembly 130 is in communication. The third opening 140 constitutes a sound entrance hole of the package structure.

Specifically, in the alternative of the embodiment, the method further includes providing a lead 102 electrically connecting one end of the lead 102 to the bonding pad 40 located in the microphone assembly 130, and the other end and the package substrate 300 The solder fillet pins 101 are electrically connected for extracting an electrical signal converted from the sound signal out of the microphone assembly 130.

Specifically, the encapsulation layer 103 is formed by a method of filling a package, and the step of forming the encapsulation layer 103 includes forming a mold covering the first opening 150, and the function of the mold is to prevent the process of filling the package. The formed encapsulation layer 103 enters the first opening 150, thereby affecting the microphone component 130 to receive a sound signal. The shape of the mold can be designed according to process requirements. In the embodiment shown in FIG. 4, the mold includes an edge away from the package substrate 300 and an edge adjacent to the package substrate 300 along a section perpendicular to the package substrate 300. The length of the side away from the package substrate 300 is greater than the length of the side near the package substrate 300.

Further, before the filling and packaging, a buffer layer may be formed on the third surface of the microphone assembly 130, the material of the buffer layer is soft rubber, and then the filling and packaging is performed, and the buffer layer and the filling mold package are used. The formed portions collectively constitute the encapsulation layer 103. The material of the portion other than the buffer layer of the encapsulation layer 103 is plastic, that is, the material of the encapsulation layer 103 includes plastic and soft rubber (buffer layer).

The method for forming the MEMS microphone package structure provided in FIG. 4 differs from the method for forming the MEMS microphone package structure provided in FIG. 5 in that:

The method of forming the MEMS microphone package structure provided in FIG. 5 differs in that the package layer 103 formed in the method of forming the MEMS microphone package structure provided in FIG. 5 covers only the third surface 30 of the microphone assembly 130. Specifically, the encapsulation layer 103 covering only the third surface 30 may be formed by first forming a mold covering the first surface 10 and the first opening 150 and then performing a mold encapsulation.

Since the process of filling and packaging has been well known to those skilled in the art, it will not be described in detail herein.

The method for forming a MEMS microphone package structure provided by the embodiment of the present invention may At the same time, a plurality of microphone components are packaged, that is, an encapsulation layer covering a plurality of microphone components can be simultaneously formed, so that the packaging process is simple and efficient.

Third embodiment

FIG. 6 is a schematic diagram of a MEMS microphone package structure according to a third embodiment of the present invention. The main difference between this embodiment and the second embodiment is that, in this embodiment, the package substrate and the microphone assembly further include An interposer of the fourth opening, the fourth opening being in communication with the second opening.

The MEMS microphone package structure provided in this embodiment includes:

a microphone assembly 130, the microphone assembly 130 including a first surface 10, and the first surface

10 opposite second surface 20, and a third surface 30 connecting the first surface 10 and the second surface 20;

The encapsulation layer 103, the encapsulation layer 103 covers the third surface 30 of the microphone assembly 130; the sound inlet hole, the sound inlet hole communicates with the first opening 150, and the sound signal is transmitted to the microphone assembly 130;

The interposer 180 is disposed between the package substrate 300 and the microphone assembly 130, and has a fourth opening 190 extending through the interposer 180. The fourth opening 190 is in communication with the second opening 160.

In this embodiment, the microphone assembly 130 is bonded to the package substrate 300 by an interposer 180. The interposer 180-surface is bonded to the package substrate 300 with a die attach adhesive, and the other surface is bonded to the microphone assembly 130 by a die attach adhesive. The role of the interposer 180 is to increase the volume of the acoustic cavity, thereby increasing microphone sensitivity.

In this embodiment, the microphone assembly 130 includes a first electrode 115 and a second electrode 120, and further includes a first opening 150 exposing the first electrode 115 and a second opening 160 exposing the second electrode 120. The first opening 150 is the sound entrance hole and is in communication with the second opening 160.

In an alternative embodiment of the present invention, the cross section of the fourth opening 190 in a direction perpendicular to the package substrate 300 includes a third side away from the package substrate 300 and a fourth side adjacent to the package substrate 300, and a third The length of the sides is less than the length of the fourth side, such as forming a trapezoidal cross section. The greater the thickness of the interposer 180, the deeper the fourth opening 190, the larger the volume of the acoustic cavity, and the better the sound effect of the MEMS microphone package structure, but the volume of the MEMS microphone package structure is correspondingly larger. Therefore, in an embodiment of the invention, the thickness of the interposer 180 is optimized. In an alternative embodiment of the invention, the thickness of the interposer 180 ranges from 100 microns to 500 microns.

In the embodiment, the first opening 150 is a sound inlet hole, that is, the sound inlet hole is disposed opposite to the package substrate 300.

In an alternative embodiment of the present invention, the MEMS microphone package structure further includes a lead 102. In the embodiment, the lead 102 is located in the encapsulation layer 103, and the lead 102 is connected to the microphone assembly 130. The bonding pad 40 is electrically connected, and the other end is electrically connected to the bonding pad 101 of the package substrate 300. The electrical signal converted from the acoustic signal is led out of the microphone assembly 130 by the bonding pad 40 and the bonding pin 101.

In an alternative embodiment of the invention, the microphone assembly includes an electromechanical system microphone 105 and a signal processing circuit 104. The MEMS microphone 105 and the signal processing circuit 104 are bonded together in a metal or metal alloy to form the microphone assembly 130. One of the advantages of the MEMS microphone 105 is its relatively small size.

In other aspects of this embodiment, the encapsulation layer 103 is a stacked structure and further includes a buffer layer that is attached to the third surface 30 of the microphone assembly 130. The material of the buffer layer is a soft gel. The material of the portion of the encapsulation layer 103 other than the buffer layer is plastic, that is, the material of the encapsulation layer 103 includes plastic and soft rubber (buffer layer). If a single-layer encapsulation layer 103 is formed directly on the third surface 30 of the microphone assembly 130, since the material of the single-layer encapsulation layer is generally selected to be a material having a relatively large thermal expansion coefficient, the microphone assembly 130 and the encapsulation layer 103 are The stress is relatively large, and in the case of being heated or stressed, damage to the encapsulation layer 103 or the microphone assembly 130 is easily caused, and the buffer layer can reduce the stress between the microphone assembly 130 and the encapsulation layer 103, and the microphone assembly The 130 and the encapsulation layer 103 form a protection.

In an alternative embodiment of the invention, the package substrate 300 is a lead frame or a printed circuit Board.

In this embodiment, sound enters the microphone assembly 130 through the sound inlet hole (first opening 150), causing the first electrode 115 to be surrounded by the second opening 160, the fourth opening 190, and the package substrate 300. The microphone assembly 130 vibrates and converts the sound signal into an electrical signal that is led out of the microphone assembly 130 via the lead 102.

With respect to the second embodiment of the present invention, the advantage of this embodiment is that the volume of the acoustic cavity is larger and the sound effect is better.

In other aspects of this embodiment, the encapsulation layer 103 may also cover both the third surface 30 of the microphone assembly 130 and the first surface 10 of the microphone assembly 130.

Correspondingly, the present invention further provides a method for forming a MEMS microphone package structure provided by the embodiment, and FIG. 17 is a schematic flow chart of the forming method, including:

Step S201, providing a microphone assembly 130, the microphone assembly 130 including a first surface 10, a second surface 20 opposite the first surface 10, and a third surface connecting the first surface 10 and the second surface 20 30;

Referring to FIG. 18, the microphone assembly 130 includes a first electrode 115 and a second electrode 120, and further includes a first opening 150 exposing the first electrode 115 and a second opening 160 exposing the second electrode 120.

Step S202, providing a package substrate 300, the package substrate 300 is used to carry the microphone assembly 130, the package substrate 300 further includes a pressure-welded pin 101;

Step S203, bonding an interposer 180 on the surface of the package substrate 300, and forming a fourth opening 190 in the interposer.

Referring to FIG. 19, in the embodiment, a fourth opening 190 may be formed in the interposer 180, and the fourth opening 190 has a third side away from the package substrate 300 in a cross section perpendicular to the package substrate 300. And a fourth side of the package substrate 300, and the length of the third side is smaller than the length of the fourth side, and then the surface of the interposer 180 including the fourth side and the package substrate are adhesively coated with an adhesive 300 bonding, and in a subsequent step, bonding the microphone assembly 130 to the surface of the interposer 180 containing the third side through the second surface 20 with an adhesive and aligning the fourth opening 190 And a second opening 160.

Of course, in other aspects of the embodiment, the interposer 180 and the microphone assembly 130 may be bonded first, and then the interposer 180 and the package substrate 300 may be bonded. In other aspects of the embodiment, one surface of the interposer 180 and the second surface 20 of the microphone assembly 130 may be bonded first, and then a fourth opening penetrating the interposer 180 and communicating with the second opening 160 may be formed. 190, then the surface of the interposer 180 opposite the surface is bonded to the package substrate 300 in a subsequent step.

Of course, in other aspects of the embodiment, the interposer 180 and the package substrate may also be bonded first.

300. After forming the fourth opening 190, the interposer 180 and the microphone assembly 130 are bonded.

Step S204, bonding the second surface 20 of the microphone assembly 130 and the surface of the interposer 180 away from the package substrate 300, and aligning the fourth opening 190 of the interposer 180 with the microphone assembly 130 The second opening 160.

Referring to FIG. 19, the package substrate 300 and the surface of the interposer 180 opposite to the second surface 20 of the microphone assembly 130 are bonded by a die attach adhesive 106, the fourth opening 190, the second opening 160, and The package substrate 300 encloses an acoustic cavity.

Step S205, forming an encapsulation layer 103 covering the third surface 30 of the microphone assembly 130. Referring to FIG. 19, prior to forming the encapsulation layer, the bonding pads 102 of the microphone assembly 130 and the bonding pads 101 of the package substrate 300 are electrically connected by wires 102.

In other aspects of the embodiment, the encapsulation layer 103 covering the third surface 30 and the first surface 10 may be formed, and the encapsulation layer covering the first surface does not completely cover the first surface, on the first surface. The encapsulation layer includes an opening communicating with the first opening as a sound inlet.

The encapsulation layer 103 may be formed by a method of filling a package. In other aspects of the embodiment, the buffer layer may be formed on the third surface 30, and then the mold is encapsulated. For the specific method, refer to the embodiment corresponding to FIG.

Fourth embodiment

7 and FIG. 8 are schematic diagrams showing a MEMS microphone package structure according to a fourth embodiment of the present invention. The main difference between this embodiment and the first embodiment is that the package substrate is a lead frame, and the lead frame further includes a bendable frame. Pin 401, in FIG. 7, the pin 401 is bent toward the package substrate 500, and the pin 401 is bent away from the package substrate 500 in FIG. The MEMS microphone package structure provided in this embodiment includes:

a microphone assembly 130, the microphone assembly 130 including a first surface 10, a second surface 20 opposite the first surface 10, and a third surface connecting the first surface 10 and the second surface 20 30;

In an embodiment of the invention, the first surface 10 is the upper surface of the microphone assembly 130, the second surface 20 is the lower surface of the microphone assembly 130, and the third surface 30 is the outer surface of the microphone assembly 130.

a package substrate 500, the package substrate 500 carrying the microphone assembly 130, and the package substrate 500 is opposite to the second surface 20 of the microphone assembly 130;

In this embodiment, the package substrate 500 is a lead frame, and the lead frame further includes a pad 402 and a pin 401. The pin 401 may be bent toward the lead frame as shown in Fig. 7, or bent away from the lead frame as shown in Fig. 8.

The pin 401 is located outside the encapsulation layer 103.

The encapsulation layer includes a third opening 140, and the third opening 140 is in communication with the first opening 150. The sound inlet hole 508 is located in the package substrate 500, communicates with the second opening 160, and transmits a sound signal to the microphone assembly 130;

The package cover 107 is disposed opposite to the package substrate 500, and the package cover 107 and the package layer 103 are bonded by the adhesive 206.

The package cover 107 and the third opening 140 define a sound cavity.

In this embodiment, the microphone assembly 130 includes a first electrode 115 and a second electrode 120, and further includes a first opening 150 exposing the first electrode 115 and a second opening 160 exposing the second electrode 120. The sound inlet hole 108 is located in the package substrate 500 and is in communication with the second opening 160.

In other embodiments of the present invention, the encapsulation layer 103 is a stacked structure, and further includes a buffer layer that is attached to the third surface 30 of the microphone assembly 130. The material of the buffer layer is a soft gel. The material of the portion of the encapsulation layer 103 other than the buffer layer is plastic, that is, the material of the encapsulation layer 103 includes plastic. And soft glue (buffer layer). If a single-layer encapsulation layer 103 is formed directly on the third surface 30 of the microphone assembly 130, since the material of the single-layer encapsulation layer is generally selected to be a material having a relatively large thermal expansion coefficient, the microphone assembly 130 and the encapsulation layer 103 are The stress is relatively large, and in the case of being heated or stressed, damage to the encapsulation layer 103 or the microphone assembly 130 is easily caused, and the buffer layer can reduce the stress between the microphone assembly 130 and the encapsulation layer 103, and the microphone assembly The 130 and the encapsulation layer 103 form a protection.

In an alternative embodiment of the present invention, the MEMS microphone package structure further includes a lead 102. In the embodiment, the lead 102 is located in the encapsulation layer 103, and the lead 102 is connected to the microphone assembly. The bonding pad 40 is electrically connected, and the other end is electrically connected to the pad 402 of the package substrate 500, so that an electrical signal converted from the acoustic signal is led out of the microphone assembly 130 by the bonding pad 40 and the pad 402.

In the present embodiment, the package substrate 500 is a lead frame, and the pins 401 are located outside the package layer 103. The bonding wire 102 is electrically connected to the pad 402 of the lead frame, and the pad 402 is electrically connected to the pin 401, thereby enabling the microphone component 130 and the pin 401 to be turned on, the pin 401 being bent toward the package substrate 500, or facing away from the package. The substrate 500 is bent to form a small outline integrated circuit package (SOIC package). Solder pad 402 is located within encapsulation layer 103.

In the present embodiment, the sound enters the microphone assembly 130 through the sound inlet hole 508, enters the first electrode 115 and the second electrode 120 via the second opening 160, causing the first electrode 115 to vibrate within the formed acoustic cavity, and The sound signal is converted to an electrical signal, and the microphone assembly 130 is taken out via the lead 102.

In the MEMS microphone package structure formed in this embodiment, the encapsulation layer and the microphone component are attached, so that the volume of the MEMS microphone package structure is reduced, and the protection effect on the microphone component is improved;

Further, in other embodiments, the encapsulation layer 103 may also cover only the third surface 30 of the microphone assembly 130. Correspondingly, the present invention further provides a method for forming a MEMS microphone package structure provided by the fourth embodiment, including:

A microphone assembly 130 is provided that includes a first surface 10, a second surface 20 opposite the first surface 10, and a third surface 30 that joins the first surface 10 and the second surface 20.

In this embodiment, the microphone assembly 130 includes a first electrode 115 and a second electrode 120, and further includes a first opening 150 exposing the first electrode 115 and a second opening 160 exposing the second electrode 120.

A package substrate 500 is provided, which is a lead frame for carrying the microphone assembly, including pads 402 and pins 401. And the pin 401 is bent.

In an embodiment of the present invention, a sound in hole 508 may be formed in the lead frame 500 first, and in the subsequent step of combining the microphone assembly 130 and the lead frame 500, the sound in hole 508 and the a second opening 160 of the microphone assembly 130; or a combination of the lead frame 500 and the microphone assembly 130, and a sound input into the lead frame 500 corresponding to the second opening 160 of the microphone assembly 130 The hole 508, the process of forming the sound entrance hole 508 can be formed by a process known to those skilled in the art, and it is required to ensure that the formed sound inlet hole 508 penetrates the second opening 160 of the microphone assembly 130.

In conjunction with the microphone assembly 130 and the lead frame 500, the lead frame 500 is opposite the second surface 20 of the microphone assembly 130.

In the present embodiment, the microphone assembly 130 and the lead frame 500 are bonded with a die attach adhesive to bond the microphone assembly 130 and the lead frame 500.

Lead wires 102 are provided, one end of which is electrically connected to the bonding pad 40 of the microphone assembly 130, and the other end is electrically connected to the pad 402 of the package substrate 500, and the pad 402 is electrically connected to the pin 401. The pin 401 is bent toward the package substrate 500 or bent away from the package substrate 500 to form a small outline integrated circuit package (SOIC package).

An encapsulation layer 103 covering the third surface 30 and the first surface 10 of the microphone assembly 130 is formed. The encapsulation layer 103 further includes a third opening 140 that communicates with the first opening 150.

In other aspects of this embodiment, the encapsulation layer 103 may also cover only the third surface 30 of the microphone assembly 130.

The encapsulation layer 103 is formed by a method of filling a package, and the material of the encapsulation layer 103 is plastic. For a specific method of filling the package, reference may be made to forming a method of forming the MEMS microphone package structure provided by the first embodiment.

A package cover 107 is provided, and the package cover 107 is disposed opposite to the lead frame 500.

In this embodiment, the package cover 107 and the encapsulation layer 103 are bonded by an adhesive 206. The material of the package cover 107 is plastic.

At this time, the package cover 107 and the third opening 140, the first opening 150 encloses an acoustic cavity. The third opening 140 formed in the encapsulation layer 103 can increase the space of the formed acoustic cavity, thereby improving the MEMS microphone sensitivity.

Fifth embodiment

9 is a schematic diagram of a MEMS microphone package structure according to a fifth embodiment of the present invention. The main difference of the fifth embodiment relative to the fourth embodiment is that the first opening in the fifth embodiment is a sound inlet hole, and the sound is inserted. The hole is opposed to the package substrate, and in the fourth embodiment, the sound entrance hole is formed in the package substrate. The MEMS microphone package structure provided in this embodiment includes:

a microphone assembly 130, the microphone assembly 130 includes a first surface 10, a second surface 20 opposite the first surface 10, and a third surface 30 connecting the first surface 10 and the second surface 20;

a package substrate 400, the package substrate 400 carrying the microphone assembly 130, and the package substrate 400 is opposite to the second surface 20 of the microphone assembly 130;

In this embodiment, the package substrate 400 is a lead frame, and the lead frame further includes a pad 402 and a pin 401. The pin 401 can be bent away from the lead frame as shown in Fig. 9, or bent toward the lead frame.

Encapsulation layer 103, the encapsulation layer 103 covers the third surface 30 of the microphone assembly 130; In the present solution, the first opening 150 constitutes a sound entrance hole. The sound entrance hole is disposed opposite to the package substrate 400 to transmit a sound signal to the microphone assembly 130.

In other aspects of this embodiment, the encapsulation layer may also cover the first surface 10 as shown in FIG. 7 or FIG. 8 and form a third opening 140. The material of the encapsulation layer 103 is plastic. The third opening 140 constitutes a sound entrance hole.

The interposer 180 is disposed between the package substrate 400 and the microphone assembly 130 and has a fourth opening 190 extending through the interposer 180. The fourth opening 190 is in communication with the second opening 160.

The fourth opening 190, the second opening 160, and the package substrate 400 enclose an acoustic cavity.

In other embodiments of the present invention, the encapsulation layer 103 may also be a stacked structure, and further includes a buffer layer that is attached to the third surface 30 of the microphone assembly 130. The material of the buffer layer is a soft gel. The material of the encapsulation layer 103 includes plastic and soft glue (buffer layer). If the single-layer encapsulation layer 103 is formed directly on the third surface 30 of the microphone assembly 130, since the material of the single-layer encapsulation layer 103 is generally selected to be a material having a relatively large thermal expansion coefficient, between the microphone assembly 130 and the encapsulation layer 103 The stress is relatively large, and in the case of being heated or stressed, the damage of the encapsulation layer 103 or the microphone assembly 130 is easily caused, and the buffer layer can reduce the stress between the microphone assembly 130 and the encapsulation layer 103, and the microphone assembly The 130 and the encapsulation layer 103 form a protection.

In an alternative embodiment of the present invention, the MEMS microphone package structure further includes a lead 102. In the embodiment, the lead 102 is located in the encapsulation layer 103, and the lead 102 is connected to the microphone assembly. The bonding pad 40 is electrically connected, and the other end is electrically connected to the pad 402 of the package substrate 400 for guiding an electrical signal converted from the sound signal out of the microphone assembly 130. In other embodiments of the invention, the lead 102 may not be included, and electrical signals may be routed out of the microphone assembly 130 by other methods known to those skilled in the art.

In the present embodiment, the microphone assembly 130 is bonded to the package substrate 400 by an interposer 180. One surface of the interposer 180 is bonded to the package substrate 400 by the die attach adhesive 106, and the other surface is bonded to the microphone component 130 by the die attach adhesive 106. The function of the interposer 180 is to increase the volume of the acoustic cavity, thereby improving the sound effect. The package substrate 400 and the fourth opening 190 and the second opening 160 enclose an acoustic cavity. In other embodiments of the present invention, the interposer 180 may not be included, and the microphone component 180 is directly connected to the package substrate 400. Package substrate 400 by adhesive bonding An acoustic cavity is enclosed with the second opening 160.

In an optional embodiment of the present invention, the fourth opening 190 has a third side away from the package substrate 400 and a fourth side close to the package substrate 400 in a section perpendicular to the direction of the package substrate 400, and The length of the three sides is smaller than the length of the fourth side, such as forming a trapezoidal cross section. The greater the thickness of the interposer 180, the deeper the fourth opening 190, the larger the volume of the acoustic cavity, and the better the sound effect of the MEMS microphone package structure, but the volume of the MEMS microphone package structure is correspondingly larger. Therefore, in an embodiment of the invention, the thickness of the interposer 180 is optimized. In an alternative embodiment of the invention, the thickness of the interposer 180 ranges from 100 microns to 500 microns.

In the present embodiment, the package substrate 400 is a lead frame, and the pins 401 are located outside the package layer 103. The bonding wire 102 is electrically connected to the pad 402 of the lead frame, and the pad 402 is electrically connected to the pin 401, so that the microphone assembly 130 and the pin 401 are turned on, and the pin 401 can be bent toward the sound in hole 208 or away from the sound. The via 208 is bent to form a small outline integrated circuit package (SOIC package). Solder pad 402 is located within encapsulation layer 103.

In this embodiment, the first opening 150 constitutes a sound inlet hole, and the sound enters the microphone assembly 130 through the sound inlet hole, and enters the first electrode 115 and the second electrode 120 via the first opening 150, causing the first electrode 115 to be in the The vibration within the formed acoustic cavity converts the acoustic signal into an electrical signal that is drawn out of the microphone assembly 130 via lead 102.

In other embodiments, the encapsulation layer 103 may further include a first surface 10 covering the microphone assembly 130 and forming a third opening in communication with the first opening 150.

In other embodiments of the present invention, the encapsulation layer 103 is a stacked structure, and further includes a buffer layer attached to the third surface 30. The buffer layer is made of a soft rubber.

In the MEMS microphone package structure formed by the embodiment, the encapsulation layer covers the microphone component, so that the volume of the MEMS microphone package structure is reduced, and the protection effect on the microphone component is improved;

Correspondingly, an embodiment of the present invention further provides a MEMS microphone package provided by the fifth embodiment. A method of forming a structure, which differs from the method of forming a MEMS microphone package structure provided by the fourth embodiment is a method of forming a sound entrance hole.

A method of forming a MEMS microphone package structure provided by the fifth embodiment includes: providing a microphone assembly 130, the microphone assembly 130 including a first surface 10, a second surface 20 opposite the first surface 10, and a connection The first surface 10 and the third surface 30 of the second surface 20 are described.

A package substrate 400 is provided, which is a lead frame for carrying the microphone assembly 130, including a pad 402 and a pin 401. The pin 401 may be bent toward the package substrate 400 as shown in FIG. 9, or may be bent away from the package substrate 400.

In combination with the microphone assembly 130, the interposer 180, and the lead frame 400, the interposer 180 is interposed between the microphone assembly 130 and the lead frame 400, and the second surface 20 of the microphone assembly 130 and the interposer 180 The surface away from the lead frame 400 is bonded together such that the second opening 160 of the microphone assembly 130 communicates with the fourth opening 190 of the interposer 180.

A lead 102 is provided, one end of the lead 102 is electrically connected to the pad sheet 40 of the microphone assembly, and the other end is electrically connected to the pad 402 of the lead frame, and the pad 402 is electrically connected to the pin 401, thereby implementing the microphone assembly. 130 and pin 401 are turned on, and pin 401 is bent toward package substrate 500 or bent away from package substrate 500 to form a small outline integrated circuit package (SOIC package).

An encapsulation layer 103 covering the third surface 30 of the microphone assembly 130 is formed. The first opening 150 constitutes a sound entrance hole.

In other aspects of the embodiment, the encapsulation layer 103 further covers the first surface 10, and the encapsulation layer 103 further includes a third opening that communicates with the first opening 150. The third opening constitutes a sound entrance hole.

The encapsulation layer 103 is formed by a method of filling and packaging, and the material of the encapsulation layer 103 is plastic. For a method of filling a package, reference may be made to forming a method for forming a MEMS microphone package provided by the first embodiment.

In this embodiment, the encapsulation layer 103 is formed by a method of filling and packaging, so that a plurality of microphone components 130 to be packaged on the same wafer can be simultaneously packaged and then separated to form an independent microphone package structure. . Compared with the existing package, the method of packaging by metal material is not only the entire package structure is small, but also can package multiple microphone components in the same batch, the packaging process is simple, the cost is low, especially the package. The efficiency is high.

In summary, in the MEMS microphone package structure formed by the embodiment of the present invention, the package layer covers the microphone component, so that the volume of the MEMS microphone package structure is reduced, and the protection effect on the microphone component is improved;

In addition, the package layer of the MEMS microphone package structure provided by the embodiment of the present invention uses plastic to reduce the weight of the MEMS microphone package structure. In an optional embodiment of the present invention, the package layer further includes a buffer layer, so that The protection effect of the microphone component is further improved. In the method for forming the MEMS microphone package structure provided by the embodiment of the present invention, multiple microphone components can be packaged at the same time, and the packaging process is simple and efficient.

The embodiments of the present invention have been disclosed in the above preferred embodiments, but they are not intended to limit the embodiments of the present invention, and any one skilled in the art can utilize the present invention without departing from the spirit and scope of the embodiments of the present invention. The method and the technical content disclosed above make possible changes and modifications to the technical solutions of the embodiments of the present invention. Therefore, the contents of the technical solutions that do not deviate from the embodiments of the present invention are all according to the embodiments of the present invention. The scope of protection of the technical solution.

Claims

Rights request

A MEMS microphone package structure, comprising:

a package substrate for carrying the microphone assembly and opposite to a second surface of the microphone assembly;

2. The MEMS microphone package structure according to claim 1, wherein the microphone assembly includes a first electrode, a second electrode, a first opening exposing the first electrode, and a first electrode exposing the second electrode Two openings.

3. The MEMS microphone package of claim 1 wherein the microphone assembly further comprises: a signal processing circuit and/or other sensors integrated with the microphone assembly.

4. The MEMS microphone package structure according to claim 2, wherein the sound in hole is located in the package substrate and communicates with the second opening.

The MEMS microphone package structure according to claim 4, wherein the encapsulation layer further covers a first surface of the microphone component, the encapsulation layer includes a third opening, the third opening and the third opening The first openings are in communication.

The MEMS microphone package structure according to claim 5, wherein the MEMS microphone package structure further comprises a package cover covering the package layer, the package cover is disposed opposite to the package substrate, and the package cover Enclosing an acoustic cavity with the first opening and the third opening.

7. The MEMS microphone package structure according to claim 5, wherein the third opening has a first side away from the package substrate and a second portion adjacent to the package substrate in a section perpendicular to the direction of the package substrate. The length of the first side is greater than the length of the second side.

8. The MEMS microphone package structure according to claim 4, wherein

The MEMS microphone package structure further includes a package cover covering the package layer, the package cover being disposed opposite the package substrate, the package cover and the first opening enclosing an acoustic cavity.

9. The MEMS microphone package structure according to claim 6 or 8, wherein the material of the package cover is plastic.

The MEMS microphone package structure according to claim 2, wherein the encapsulation layer further covers a first surface of the microphone component, the encapsulation layer includes a third opening, the third opening and the third opening The first opening is in communication, and the sound inlet hole is the third opening.

The MEMS microphone package structure according to claim 2, wherein the sound entrance hole is the first opening.

The MEMS microphone package structure according to claim 10 or 11, wherein the package substrate and the second opening enclose an acoustic cavity.

The MEMS microphone package structure according to claim 10 or 11, wherein the package substrate and the microphone assembly further comprise an interposer, the interposer has a fourth opening, and the fourth opening The second opening is in communication, and the package substrate and the second opening and the fourth opening enclose an acoustic cavity.

14. The MEMS microphone package structure according to claim 13, wherein the fourth opening has a third side away from the package substrate and a fourth portion adjacent to the package substrate in a section perpendicular to the direction of the package substrate. The length of the third side is smaller than the length of the fourth side.

15. The MEMS microphone package structure according to claim 1, wherein the microphone assembly further comprises a lead wire, one end of the lead wire is electrically connected to a pressure bonding plate piece located on the microphone component, and the other end is opposite to the package. The substrate is electrically connected to extract an electrical signal converted from the sound signal out of the microphone assembly.

The MEMS microphone package structure according to claim 1, wherein the package substrate is a lead frame or a printed circuit board.

17. The MEMS microphone package of claim 1 wherein the encapsulation layer comprises a buffer layer in close contact with the third surface of the microphone assembly.

The MEMS microphone package structure according to claim 17, wherein the material of the buffer layer is a soft glue.

19. The MEMS microphone package of claim 1 wherein the material of the encapsulation layer comprises plastic.

20. A method of forming a MEMS microphone package structure, comprising: providing a microphone assembly, the microphone assembly including a first surface, a second surface opposite the first surface, and connecting the first surface And a third surface of the second surface; Providing a package substrate, the package substrate for carrying the microphone assembly;

Combining the microphone assembly with the package substrate, the package substrate is opposite to a second surface of the microphone assembly;

The method of forming a MEMS microphone package structure according to claim 20, wherein the microphone assembly comprises a first electrode, a second electrode, a first opening exposing the first electrode, and exposing the second a second opening of the electrode.

The method of forming a MEMS microphone package structure according to claim 21, further comprising: forming a sound entrance hole for introducing a sound signal into the microphone component on the package substrate, the sound entrance hole and the sound The second opening is in communication.

The method of forming a MEMS microphone package structure according to claim 22, further comprising: forming a package cover covering the package layer, wherein the package cover is disposed opposite to the package substrate.

24. The method of forming a MEMS microphone package structure according to claim 23, wherein the material of the package cover is plastic.

The method of forming a MEMS microphone package structure according to claim 24, wherein the encapsulation layer further covers a first surface of the microphone component, and the method for forming the MEMS microphone package structure further comprises: The encapsulation layer covering the first surface of the microphone assembly forms a third opening, and the third opening is in communication with the first opening.

The method of forming a MEMS microphone package structure according to claim 25, wherein the third opening has a first side away from the package substrate and adjacent to the package substrate in a section perpendicular to the direction of the package substrate. The second side has a length greater than a length of the second side.

The method of forming a MEMS microphone package structure according to claim 21, wherein the encapsulation layer further covers a first surface of the microphone component, and the method for forming the MEMS microphone package structure further comprises: The encapsulation layer covering the first surface of the microphone assembly forms a third opening, and the third opening is in communication with the first opening, and the third opening is a sound inlet hole for introducing a sound signal into the microphone assembly.

28. The method of forming a MEMS microphone package structure according to claim 21, wherein the first opening is a sound entrance hole for introducing a sound signal into the microphone assembly.

The method of forming a MEMS microphone package structure according to claim 27 or 28, wherein the combining the microphone component and the package substrate comprises:

Bonding an interposer on the surface of the package substrate;

Forming a fourth opening in the interposer, the fourth opening being in communication with the second opening; bonding a second surface of the microphone assembly and a surface of the interposer away from the package substrate, and aligning the same A fourth opening of the interposer and a second opening of the microphone assembly.

30. The method of forming a MEMS microphone package structure according to claim 29, wherein the fourth opening has a third side away from the package substrate and adjacent to the package substrate in a section perpendicular to the direction of the package substrate. The fourth side has a length smaller than a length of the fourth side.

31. A method of forming a MEMS microphone package structure according to claim 20, wherein the package layer is formed using a die package.

32. A method of forming a MEMS microphone package structure according to claim 20, wherein the step of forming the encapsulation layer further comprises forming a buffer layer on a third surface of the microphone assembly.

33. A method of forming a MEMS microphone package structure according to claim 32, wherein the material of the mold package is plastic.

34. A method of forming a MEMS microphone package structure according to claim 33, wherein the step of potting the package comprises forming a mold covering the first opening of the microphone assembly.