WO2021128418A1

WO2021128418A1 - Microphone packaging structure and electronic device

Info

Publication number: WO2021128418A1
Application number: PCT/CN2019/130624
Authority: WO
Inventors: 庞胜利
Original assignee: 潍坊歌尔微电子有限公司
Priority date: 2019-12-26
Filing date: 2019-12-31
Publication date: 2021-07-01
Also published as: CN111050259A

Abstract

The embodiments of the present invention disclose a microphone packaging structure and an electronic device. The packaging structure comprises: a housing, a cavity being formed inside the housing, at least a part of the housing comprising a first layer and a second layer which are provided in the thickness direction, and an accommodating cavity being formed between the first layer and the second layer; an MEMS acoustic chip, the MEMS acoustic chip being provided within the cavity; and an ASIC chip, the ASIC chip being provided within the accommodating cavity, the ASIC chip being connected to the MEMS chip. The ASIC chip does not occupy the space of the cavity, so that the adjustment effect of the cavity on sound pickup is more prominent, and the acoustic-electro conversion effect of the microphone packaging structure is better.

Description

Microphone packaging structure and electronic equipment

Technical field

The present invention relates to the technical field of acoustic-electric conversion, and more specifically, to a microphone packaging structure and electronic equipment.

Background technique

The microphone package structure usually includes a housing, a MEMS acoustic chip, and an ASIC chip. The ASIC chip is an application-specific integrated circuit chip. The ASIC chip is generally used to amplify the electrical signal of the MEMS acoustic chip, and the ASIC chip can provide a bias voltage to the MEMS chip to make it work.

The MEMS acoustic chip and the ASIC chip are usually arranged in a cavity enclosed by a housing. A sound pickup hole is provided on the shell. The diaphragm of the MEMS acoustic chip is opposite to the pickup hole. The cavity of the microphone packaging structure plays a role in adjusting the sound pickup effect. The larger the volume of the cavity, the better the sound pickup effect; the smaller the volume of the cavity, the worse the sound pickup effect. The ASIC chip is arranged in the cavity, which reduces the volume of the cavity.

Therefore, it is necessary to provide a new technical solution to solve at least one of the above-mentioned technical problems.

Summary of the invention

An object of the present invention is to provide a new technical solution for the microphone packaging structure.

According to the first aspect of the present invention, a microphone packaging structure is provided. The packaging structure includes a housing, a cavity is formed inside the housing, and at least a part of the housing includes a first layer and a second layer arranged in a thickness direction. A accommodating cavity is formed between the two layers; a MEMS acoustic chip, the MEMS acoustic chip is arranged in the cavity; and an ASIC chip, the ASIC chip is arranged in the accommodating cavity, the ASIC chip is connected to the MEMS Chip connection.

Optionally, it further includes a shielding layer, the shielding layer is disposed on the housing, and the shielding layer is configured to shield the ASIC chip.

Optionally, the shielding layer is provided on the surface or inside of the first layer; and/or the shielding layer is provided on the surface or inside of the second layer.

Optionally, the first layer is close to the cavity, and a metalized through hole is provided in the first layer, and the MEMS acoustic chip is connected to the ASIC chip through the metalized through hole.

Optionally, the MEMS acoustic chip is connected to the metallized through hole through a first gold wire; or the MEMS acoustic chip is flip-mounted in the housing and passes through the conductive layer of the housing and the metal化 through-hole connection.

Optionally, the ASIC chip is connected to the metallized through hole through a second gold wire or a bonding pad.

Optionally, the ASIC chip is fixed in the containing cavity by an adhesive.

Optionally, the housing includes a substrate assembly and a cover, the cover and the substrate assembly enclose the cavity, the substrate assembly includes a first substrate and a second substrate, and the first layer includes The first substrate is connected to the cover, and the second layer includes the second substrate.

Optionally, during assembly, first, the ASIC chip is fixed on the first substrate by a first adhesive, and a connection is formed with the MEMS acoustic chip;

Then, a second adhesive is disposed on the second substrate;

Finally, the second substrate is attached to the first substrate, and the second adhesive is connected to the ASIC chip.

Optionally, at least one of the first substrate and the second substrate is a PCB, and at least a part of the conductor layer of the PCB is opposite to the ASIC chip.

Optionally, the first layer and the second layer are connected together by bonding, clamping or welding.

Optionally, a filter is further included, the filter is arranged in the cavity or buried in the wall of the housing, and the filter is connected to the ASIC chip.

Optionally, the filter is connected to an external device through a conductor layer of the housing, and the filter is connected to the ASIC chip through a metalized through hole.

According to another aspect of the present disclosure, an electronic device is provided. The electronic device includes a device casing and the above-mentioned microphone packaging structure, and the microphone packaging structure is arranged in the device casing.

According to an embodiment of the present disclosure, the ASIC chip does not occupy the space of the cavity, which makes the cavity adjust the sound pickup effect more prominently, and the acoustic-electric conversion effect of the microphone packaging structure is better.

Through the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become clear.

Description of the drawings

The drawings incorporated in the specification and constituting a part of the specification illustrate the embodiments of the present invention, and together with the description are used to explain the principle of the present invention.

FIG. 1 is a cross-sectional view of a microphone packaging structure according to an embodiment of the present disclosure.

Fig. 2 is a cross-sectional view of a second microphone packaging structure according to an embodiment of the present disclosure.

Fig. 3 is a cross-sectional view of a third microphone packaging structure according to an embodiment of the present disclosure.

Fig. 4 is a cross-sectional view of a fourth microphone packaging structure according to an embodiment of the present disclosure.

Detailed ways

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

The following description of at least one exemplary embodiment is actually only illustrative, and in no way serves as any limitation to the present invention and its application or use.

The technologies, methods, and equipment known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be regarded as part of the specification.

In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiment may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings.

According to an embodiment of the present disclosure, a microphone packaging structure is provided. As shown in FIG. 1, the packaging structure includes: a housing, a MEMS acoustic chip 14 and an ASIC chip 15.

A cavity 111 is formed inside the casing. The material of the shell is plastic, ceramic or PCB. The whole shell has a structure such as a rectangular parallelepiped, a cylinder, or an elliptical cylinder. At least a part of the casing includes a first layer and a second layer arranged in a thickness direction. For example, one side of the casing includes the first layer and the second layer; or the whole casing includes the first layer and the second layer.

The thickness direction is shown as d in Figure 1. A receiving cavity is formed between the first layer and the second layer. For example, the first layer and the second layer are connected together by bonding, clamping or welding. The above connection method is easy to set up, and the connection between the first layer and the second layer is firm.

The MEMS acoustic chip 14 is arranged in the cavity 111. The MEMS acoustic chip 14 is used to convert sound signals into electrical signals. As shown in FIG. 1, for example, the MEMS acoustic chip 14 includes a substrate 145, a back plate 144 and a diaphragm 142. The substrate 145 has a hollow structure, and a back cavity 143 is formed in the substrate 145. For example, the cross section of the substrate 145 has a circular ring shape. The substrate is made of insulating materials, such as silicon dioxide, silicon nitride, and the like. The back plate 144 and the diaphragm 142 are fixed on the substrate 145 and suspended in the back cavity 143. The back plate 144 and the substrate 145 respectively serve as two electrode plates of a parallel plate capacitor. The back plate 144 is a conductor or a semiconductor. The diaphragm 142 is a conductor or a semiconductor.

For example, the MEMS acoustic chip 14 is fixed on the inner wall of the housing by glue 132. A sound pickup hole 134 connecting the cavity 111 and the external space is provided on the inner wall. External sound enters the cavity 111 through the sound pickup hole 134 and drives the diaphragm 142 to vibrate. The vibration of the diaphragm 142 causes a change in capacitance, thereby forming an electrical signal.

The ASIC chip 15 is arranged in the accommodating cavity, for example, the ASIC chip 15 is fixed in the accommodating cavity by glue 132. The ASIC chip 15 is connected to the MEMS acoustic chip 14. The ASIC chip 15 is used to provide a bias voltage to the MEMS acoustic chip 14, and the ASIC chip 15 can amplify the electrical signal of the MEMS acoustic chip 14 and output the amplified electrical signal.

In an embodiment of the present disclosure, at least a part of the casing includes a first layer and a second layer arranged in a thickness direction. A receiving cavity is formed between the first layer and the second layer. The ASIC chip 15 is arranged in the accommodating cavity. In this way, the ASIC chip 15 does not occupy the space of the cavity 111, which makes the adjustment effect of the cavity 111 on the sound pickup effect more significant, and the acoustic-electric conversion effect of the microphone packaging structure is better.

In addition, in an example, during assembly, the ASIC chip 15 is first placed in the accommodating cavity, and then the first layer and the second layer are connected together. The split-assembled two-layer (ie, the first layer and the second layer) structure makes the installation of the ASIC chip 15 easier.

In addition, the ASIC chip 15 is embedded in the housing. In this way, the electromagnetic shielding effect of the housing on the ASIC chip 15 is more significant, which makes the ASIC chip 15 more resistant to interference.

In an example, as shown in FIGS. 1 to 4, the housing includes a substrate assembly and a cover 11. The whole of the cover 11 is a rectangular parallelepiped, a cylinder, an elliptic cylinder, and the like. One end of the cover 11 is open. The substrate assembly includes a plurality of substrates bonded together. The base plate assembly is fixed on the open end of the cover 11. For example, the connection is made by bonding, snapping, etc. The cover 11 and the substrate assembly enclose the cavity 111.

In other examples, the housing includes a bottom plate, a circuit board frame, and a substrate. The circuit board frame is a hollow structure. The base plate and the bottom plate respectively fix the two open ends of the hollow structure. The bottom plate, circuit board frame or substrate includes a first layer and a second layer. The ASIC chip 15 is buried between the first layer and the second layer.

In an example, as shown in FIG. 1, the package structure further includes a shielding layer. For example, the shielding layer is a metal layer. The material of the metal layer can be, but is not limited to, gold, silver, copper, nickel, zinc, etc. The shielding layer is provided on the housing. The shielding layer is configured to form a shield for the ASIC chip 15. For example, the shielding layer is connected to the ground of the external device through the ground pad 122.

For example, the metal layer is attached to the surface of the casing close to the cavity 111 or the surface opposite to the cavity 111; it is also possible that the metal layer is buried in the casing. The metal layer is located on a side of the ASIC chip 15 close to the cavity 111 and/or a side away from the cavity 111.

The metal layer is a separate layer; or the housing is a PCB (printed circuit board), and the metal layer is the conductor layer 123 in the PCB.

For example, the metal layer forms a Faraday cage. The Faraday cage is a closed structure formed by a metal layer, or a grid structure with a hollow pattern. Both of these two structures have the effect of electromagnetic shielding.

Of course, the shielding layer is not limited to the above embodiments, and those skilled in the art can set it according to actual needs.

In an example, as shown in FIGS. 1 to 4, at least one of the first substrate 12 and the second substrate 13 is a PCB, and at least part of the conductor layer 123 of the PCB is connected to the ASIC chip 15 relatively. In this example, the conductor layer 123 of the PCB can have an electromagnetic shielding effect on the ASIC chip 15, so that no additional shielding layer is required.

In an example, the shielding layer is provided on the surface or inside of the first layer; and/or

The shielding layer is provided on the surface or inside of the second layer.

For example, the surface of the first layer and the second layer refers to the upper and lower surfaces of each layer in the thickness direction; the interior refers to the part of each layer located between the two surfaces. The above setting methods can form a good electromagnetic shielding effect.

In an example, as shown in FIG. 1, the first layer is close to the cavity 111. For example, the open end of the cover 11 is connected to the first layer. A metalized through hole 121 is provided in the first layer. The MEMS acoustic chip 14 is connected to the ASIC chip 15 through the metalized through hole 121. For example, the MEMS acoustic chip 14 is connected to the metalized through hole 121. The metallized through hole 121 is connected to the ASIC chip 15 through the pad 122.

The metalized through hole 121 may be formed with a metal layer on the inner wall through which the components on the two surfaces are connected, or the through hole is filled with metal wires, and the components on the two surfaces are connected through the metal wires. through.

In an example, as shown in FIG. 1, the MEMS acoustic chip 14 is connected to the metalized through hole 121 through a first gold wire 141. For example, the MEMS acoustic chip 14 adopts a formal mounting method. The substrate 145 of the MEMS acoustic chip 14 is connected to the substrate assembly. The diaphragm 142 and the back plate 144 are away from the housing, such as the substrate assembly. The back cavity 143 communicates with the sound pickup hole 134. The external sound passes through the sound pickup hole 134 and the back cavity 143 to reach the diaphragm 142 in sequence. One end of the first gold wire 141 is welded to one end of the metallized through hole 121. The other end of the first gold wire 141 is connected to the MEMS acoustic chip 14.

Alternatively, as shown in FIG. 2, the MEMS acoustic chip 14 is flip-mounted in the housing, and is connected to the metalized through hole 121 through the conductor layer 123 of the housing. In this example, the diaphragm 142 side of the MEMS acoustic chip 14 is bonded to the substrate assembly by glue 132. The diaphragm 142 and the back plate 144 are close to the housing, such as a substrate assembly. The diaphragm 142 is opposite to the sound pickup hole 134, and the back cavity 143 is located on the side of the diaphragm 142 opposite to the sound pickup hole 134. On the side of the diaphragm 142 of the acoustic chip, for example, an electrical connection portion is provided on the top of the substrate 145. The electrical connection part is soldered to the substrate assembly through the pad 122, and is connected to the metallized through hole 121 through the conductor layer 123 of the substrate assembly.

Compared with the formal mounting method, the flip mounting method makes the volume of the cavity 111 inside the diaphragm 142 larger, which makes the cavity 111 more effective in adjusting the sound pickup effect.

In an example, as shown in FIG. 4, the ASIC chip 15 is connected to the metallized via 121 through a second gold wire 133. For example, the second gold wire 133 is located on one side of the ASIC chip 15 perpendicular to the thickness direction. One end of the second gold wire 133 is soldered to the output end of the ASIC chip 15, and the other end is soldered to the metalized through hole 121.

The second gold wire 133 can adapt to different mounting positions, which reduces the requirement on the assembly accuracy of the ASIC chip 15 and makes the connection between the ASIC chip 15 and the metalized through hole 121 easier.

In an example, the ASIC chip 15 is fixed in the receiving cavity by an adhesive. For example, the adhesive is glue 132 commonly used in the art. Those skilled in the art can make selections according to actual needs.

In an example, as shown in FIG. 1, the substrate assembly includes a first substrate 12 and a second substrate 13. The first layer includes the first substrate 12. The first substrate 12 is connected to the cover 11. The second layer includes the second substrate 13.

In this example, the substrate assembly includes a first substrate 12 and a second substrate 13 connected together. A groove 131 is provided on at least one of the first substrate 12 and the second substrate 13. During assembly, first, the ASIC chip 15 is fixed in the groove 131, for example, by glue 132. The ASIC chip 15 is connected to the metallized through hole 121 on the first substrate 12 through the bonding pad 122 or the second gold wire 133. Then, the first substrate 12 and the second substrate 13 are assembled together. The groove 131 is closed to form a receiving cavity.

In an example, as shown in FIG. 4, during assembly, first, the ASIC chip 15 is fixed on the first substrate 12 by a first adhesive, and is connected to the MEMS acoustic chip 14. For example, the first adhesive is glue 132. Firstly, the first adhesive is coated on the ASIC chip 15 and/or the first substrate 12, and then the ASIC chip 15 is bonded on the first substrate 12. The ASIC chip 15 is connected to the metallized through hole 121 on the first substrate 12 through the pad 122 or the second metal wire. The MEMS acoustic chip 15 is fixed on the surface of the first substrate 12 close to the cavity 111. The MEMS acoustic chip 14 is connected to the ASIC chip 15. In this way, the acoustic chip 14 and the ASIC chip 15 and the first substrate 12 form an assembly. This makes the positions of the acoustic chip 14 and the ASIC chip 15 on the substrate assembly more accurate.

Then, a second adhesive is disposed on the second substrate 13. For example, the second adhesive is glue 132.

Finally, the second substrate 13 is attached to the first substrate 12 and the second adhesive is connected to the ASIC chip 15. In this way, the upper and lower ends of the ASIC chip 15 are fixedly connected to the substrate assembly through the glue 132.

In an example, as shown in FIG. 3, the package structure further includes a filter 16. The filter 16 is disposed in the cavity 111. For example, the filter 1 includes at least one of a capacitive filter, a resistive filter, an inductive filter, and a varistor filter. The above-mentioned filters 16 can all have a filtering effect.

For example, the filter 16 is provided in the cavity 111. The filter 16 is connected to the output terminal of the ASIC chip 15. In this way, the filter 16 can effectively filter the interference of the radio frequency interference entering the ASIC chip 15 through the output terminal to the MEMS acoustic chip 14. The filter 16 is connected to the power terminal of the ASIC chip 15. In this way, the filter 16 can effectively filter out the interference of the power supply to the MEMS acoustic chip 14.

Alternatively, the filter 16 may be embedded in the wall of the housing. The filter 16 is connected to the ASIC chip 15. In this example, the filter 16 does not occupy the space in the cavity 111, which makes the volume of the cavity 111 larger. The cavity 111 has a more significant adjustment effect on the sound pickup effect.

In an example, as shown in FIG. 2, the filter 16 is connected to an external device through the conductor layer 123 of the housing, and the filter 16 is connected to the ASIC chip 15 through a metalized through hole 121. For example, the filter 16 is connected to the conductive layer through the pad 122, is connected to the metalized through hole 121 through the conductor layer 123, and is connected to the ASIC chip 15 through the metalized through hole 121 and the pad 122. Compared with connecting through metal wires, this arrangement does not form an antenna effect. That is, the metal wire itself can be used as an antenna to generate secondary radiation, and the way that the pad 122 and the conductor layer 123 are connected to the ASIC will not generate secondary radiation.

According to another embodiment of the present disclosure, an electronic device is provided. The electronic device includes a device casing and the above-mentioned microphone packaging structure, and the microphone packaging structure is arranged in the device casing.

The electronic device has the characteristics of good sound pickup effect.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the invention is defined by the appended claims.

Claims

A microphone packaging structure, characterized in that it comprises:

A housing, a cavity is formed inside the housing, at least a part of the housing includes a first layer and a second layer arranged in a thickness direction, and is formed between the first layer and the second layer Containment cavity

A MEMS acoustic chip, the MEMS acoustic chip being arranged in the cavity; and

An ASIC chip, the ASIC chip is arranged in the accommodating cavity, and the ASIC chip is connected to the MEMS chip.
The microphone packaging structure according to claim 1, further comprising a shielding layer, the shielding layer is disposed on the housing, and the shielding layer is configured to shield the ASIC chip.
The microphone packaging structure according to claim 2, wherein the shielding layer is provided on the surface or inside of the first layer; and/or

The shielding layer is provided on the surface or inside of the second layer.
The microphone packaging structure of claim 1, wherein the first layer is close to the cavity, and a metalized through hole is provided in the first layer, and the MEMS acoustic chip passes through the metalized The through hole is connected to the ASIC chip.
The microphone packaging structure according to claim 4, wherein the MEMS acoustic chip is connected to the metallized through hole through a first gold wire; or

The MEMS acoustic chip is flip-mounted in the housing, and is connected to the metalized through hole through the conductor layer of the housing.
The microphone packaging structure of claim 4, wherein the ASIC chip is connected to the metallized through hole through a second gold wire or a bonding pad.
The microphone packaging structure of claim 1, wherein the ASIC chip is fixed in the containing cavity by an adhesive.
The microphone packaging structure according to claim 1, wherein the housing includes a substrate assembly and a cover, the cover and the substrate assembly enclose the cavity, and the substrate assembly includes a first substrate And a second substrate, the first layer includes the first substrate, the first substrate is connected to the cover, and the second layer includes the second substrate.
8. The microphone packaging structure of claim 8, wherein when assembling,

First, the ASIC chip is fixed on the first substrate by a first adhesive, and is connected to the MEMS acoustic chip;

Then, a second adhesive is disposed on the second substrate;

Finally, the second substrate is attached to the first substrate, and the second adhesive is connected to the ASIC chip.
8. The microphone packaging structure according to claim 8, wherein at least one of the first substrate and the second substrate is a PCB, and at least a part of a conductor layer of the PCB is opposite to the ASIC chip.
The microphone packaging structure according to claim 1, wherein the first layer and the second layer are connected together by bonding, clamping or welding.
The microphone packaging structure according to claim 1, further comprising a filter, the filter is disposed in the cavity or buried in the wall of the housing, and the filter is in contact with the The ASIC chip connection.
The microphone packaging structure of claim 12, wherein the filter is connected to an external device through a conductor layer of the housing, and the filter is connected to the ASIC chip through a metalized through hole.
An electronic device, characterized by comprising a device casing and the microphone packaging structure according to any one of claims 1-13, the microphone packaging structure being arranged in the device casing.