Microphone packaging structure and electronic device

Abstract

The embodiment of the present invention discloses a microphone packaging structure and an electronic device. The packaging structure includes: a shell, a cavity is formed inside the shell, at least a part of the shell includes a first layer and a second layer arranged along the thickness direction, and a receiving cavity is formed between the first layer and the second layer; a MEMS acoustic chip, the MEMS acoustic chip is arranged in the cavity; and an ASIC chip, the ASIC chip is arranged in the receiving cavity, and the ASIC chip is connected to the MEMS acoustic chip. The ASIC chip does not occupy the space of the cavity, which makes the regulating effect of the cavity on the sound pickup effect more significant, and the sound-to-electric conversion effect of the microphone packaging structure is better.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic-electric conversion, and more specifically, to a microphone packaging structure and an electronic device. Background Art

[0002] The microphone packaging 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 usually 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 enable it to work.

[0003] MEMS acoustic chips and ASIC chips are usually placed in a cavity surrounded by a shell. A sound pickup hole is provided on the shell. The diaphragm of the MEMS acoustic chip is opposite to the sound 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 placed in the cavity, which will reduce the volume of the cavity.

[0004] Therefore, it is necessary to provide a new technical solution to solve at least one of the above technical problems. Summary of the invention

[0005] An object of the present invention is to provide a new technical solution for a microphone packaging structure.

[0006] According to a first aspect of the present invention, a microphone packaging structure is provided. The packaging structure comprises: a shell, a cavity is formed inside the shell, at least part of the shell comprises a first layer and a second layer arranged along a thickness direction, and a receiving cavity is formed between the first layer and the second layer; a MEMS acoustic chip, the MEMS acoustic chip is arranged in the cavity; and an ASIC chip, the ASIC chip is arranged in the receiving cavity, and the ASIC chip is connected to the MEMS acoustic chip.

[0007] Optionally, a shielding layer is further included, wherein the shielding layer is disposed on the housing and is configured to shield the ASIC chip.

[0008] Optionally, the shielding layer is disposed on the surface or inside of the first layer; and / or the shielding layer is disposed on the surface or inside of the second layer.

[0009] Optionally, the first layer is close to the cavity, a metallized through hole is provided in the first layer, and the MEMS acoustic chip is connected to the ASIC chip through the metallized through hole.

[0010] Optionally, the MEMS acoustic chip is connected to the metallized through hole via a first gold wire; or the MEMS acoustic chip is flip-chip mounted in the shell and connected to the metallized through hole via a conductor layer of the shell.

[0011] Optionally, the ASIC chip is connected to the metallized through hole through a second gold wire or a pad.

[0012] Optionally, the ASIC chip is fixed in the accommodating cavity by an adhesive.

[0013] Optionally, the shell includes a substrate assembly and a cover body, the cover body and the substrate assembly enclose the cavity, 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 body, and the second layer includes the second substrate.

[0014] Optionally, during assembly, first, the ASIC chip is fixed on the first substrate by a first adhesive and connected to the MEMS acoustic chip;

[0015] Then, disposing a second adhesive on the second substrate;

[0016] Finally, the second substrate is attached to the first substrate, and the second adhesive is connected to the ASIC chip.

[0017] Optionally, at least one of the first substrate and the second substrate is a PCB, and at least a portion of a conductor layer of the PCB is opposite to the ASIC chip.

[0018] Optionally, the first layer and the second layer are connected together by bonding, clamping or welding.

[0019] Optionally, a filter is further included, and the filter is arranged in the cavity or buried in the wall of the shell, and the filter is connected to the ASIC chip.

[0020] 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 metallized through hole.

[0021] According to another aspect of the present disclosure, an electronic device is provided, which includes a device housing and the above-mentioned microphone packaging structure, wherein the microphone packaging structure is disposed in the device housing.

[0022] According to one embodiment of the present disclosure, the ASIC chip does not occupy the space of the cavity, which makes the regulating effect of the cavity on the sound pickup effect more significant and the sound-to-electricity conversion effect of the microphone packaging structure better.

[0023] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0025] Figure 1 is a cross-sectional view of a microphone packaging structure according to an embodiment of the present disclosure.

[0026] Figure 2 is a cross-sectional view of a second microphone packaging structure according to an embodiment of the present disclosure.

[0027] Figure 3 is a cross-sectional view of a third microphone packaging structure according to an embodiment of the present disclosure.

[0028] Figure 4 is a cross-sectional view of a fourth microphone packaging structure according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0030] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0031] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0032] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0033] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0034] According to one embodiment of the present disclosure, a microphone packaging structure is provided. Figure 1 As shown, the packaging structure includes: a shell, a MEMS acoustic chip 14 and an ASIC chip 15.

[0035] A cavity 111 is formed inside the shell. The shell is made of plastic, ceramic or PCB. The shell is in the form of a rectangular parallelepiped, a cylinder or an elliptical cylinder. At least part of the shell includes a first layer and a second layer arranged in the thickness direction. For example, one side of the shell includes the first layer and the second layer; or the shell includes the first layer and the second layer as a whole.

[0036] Thickness direction Figure 1 As shown in d. 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.

[0037] The MEMS acoustic chip 14 is disposed in the cavity 111. The MEMS acoustic chip 14 is used to convert sound signals into electrical signals. Figure 1 As shown, for example, the MEMS acoustic chip 14 includes a substrate 145, a back plate 144 and a diaphragm 142. The substrate 145 is a hollow structure, and a back cavity 143 is formed inside it. For example, the cross-section of the substrate 145 is circular. The substrate is made of insulating material, such as silicon dioxide, silicon nitride, etc. 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.

[0038] For example, the MEMS acoustic chip 14 is fixed to the inner wall of the housing by glue 132. A sound pickup hole 134 is provided on the inner wall to connect the cavity 111 with the external space. 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.

[0039] The ASIC chip 15 is disposed 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.

[0040] In the disclosed embodiment, at least part of the housing includes a first layer and a second layer arranged in the thickness direction. A receiving cavity is formed between the first layer and the second layer. The ASIC chip 15 is arranged in the receiving cavity. In this way, the ASIC chip 15 does not occupy the space of the cavity 111, which makes the regulating effect of the cavity 111 on the sound pickup effect more significant, and the sound-to-electric conversion effect of the microphone packaging structure is better.

[0041] In addition, in one example, when assembling, the ASIC chip 15 is first placed in the receiving cavity, and then the first layer and the second layer are connected together. The two-layer (i.e., first layer and second layer) structure of the split assembly type makes it easier to install the ASIC chip 15.

[0042] In addition, the ASIC chip 15 is embedded in the housing, so that the housing has a more significant electromagnetic shielding effect on the ASIC chip 15, which makes the ASIC chip 15 more resistant to interference.

[0043] In an example, Figure 1-Figure 4 As shown, the shell includes a substrate assembly and a cover body 11. The cover body 11 is in the shape of a cuboid, a cylinder, an elliptical cylinder, etc. One end of the cover body 11 is open. The substrate assembly includes a plurality of substrates bonded together. The substrate assembly is fixed to the open end of the cover body 11. For example, the connection is performed by bonding, clamping, etc. The cover body 11 and the substrate assembly enclose the cavity 111.

[0044] 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 substrate and the bottom plate fix two open ends of the hollow structure respectively. The bottom plate, the circuit board frame or the substrate includes a first layer and a second layer. The ASIC chip 15 is buried between the first layer and the second layer.

[0045] In an example, Figure 1 As shown, 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 arranged on the housing. The shielding layer is configured to shield the ASIC chip 15. For example, the shielding layer is connected to the ground wire of the external device through the ground pad 122.

[0046] For example, the metal layer is attached to the surface of the housing close to the cavity 111 or the surface opposite to the cavity 111; or the metal layer is buried in the housing. The metal layer is located on the side of the ASIC chip 15 close to the cavity 111 and / or the side away from the cavity 111.

[0047] The metal layer is a separately provided layer; or the housing is a PCB (printed circuit board), and the metal layer is a conductor layer 123 in the PCB.

[0048] For example, the metal layer forms a Faraday cage. A Faraday cage is a closed structure formed by a metal layer, or a mesh structure with a hollow pattern. Both structures can achieve the effect of electromagnetic shielding.

[0049] Of course, the shielding layer is not limited to the above embodiments, and those skilled in the art can configure it according to actual needs.

[0050] In an example, Figure 1-Figure 4 As shown, at least one of the first substrate 12 and the second substrate 13 is a PCB, and at least a portion of the conductor layer 123 of the PCB is opposite to the ASIC chip 15. In this example, the conductor layer 123 of the PCB can provide electromagnetic shielding for the ASIC chip 15, so there is no need to set up an additional shielding layer.

[0051] In one example, the shielding layer is disposed on the surface or inside of the first layer; and / or

[0052] The shielding layer is disposed on the surface or inside of the second layer.

[0053] For example, the surface of the first layer and the second layer refers to the upper and lower surfaces of each layer along the thickness direction; the interior refers to the part of each layer located between the two surfaces. The above arrangement methods can form a good electromagnetic shielding effect.

[0054] In an example, Figure 1 As shown, 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 metallized through hole 121 is provided in the first layer. The MEMS acoustic chip 14 is connected to the ASIC chip 15 through the metallized through hole 121. For example, the MEMS acoustic chip 14 is connected to the metallized through hole 121. The metallized through hole 121 is connected to the ASIC chip 15 through the pad 122.

[0055] The metallized through hole 121 may have a metal layer formed on the inner wall, and the metal layer is used to achieve conduction between components on two surfaces, or a metal wire is filled in the through hole, and the metal wire is used to achieve conduction between components on two surfaces.

[0056] In an example, Figure 1As shown, the MEMS acoustic chip 14 is connected to the metallized through-hole 121 through a first gold wire 141. For example, the MEMS acoustic chip 14 is mounted in a positive manner. 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 shell, such as the substrate assembly. The back cavity 143 is connected to the pickup hole 134. External sound passes through the pickup hole 134 and the back cavity 143 in turn to reach the diaphragm 142. 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.

[0057] It can also be, Figure 2 As shown, the MEMS acoustic chip 14 is flipped in the shell and connected to the metallized through-hole 121 through the conductor layer 123 of the shell. In this example, one side of the diaphragm 142 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 shell, such as the substrate assembly. The diaphragm 142 is opposite to the pickup hole 134, and the back cavity 143 is located on the side of the diaphragm 142 opposite to the pickup hole 134. An electrical connection portion is provided on one side of the diaphragm 142 of the acoustic chip, such as the top of the substrate 145. The electrical connection portion is soldered to the substrate assembly through the pad 122 and connected to the metallized through-hole 121 through the conductor layer 123 of the substrate assembly.

[0058] Compared with the upright mounting method, the inverted mounting method makes the volume of the cavity 111 inside the diaphragm 142 larger, which makes the adjustment effect of the cavity 111 on the sound pickup effect more effective.

[0059] In an example, Figure 4 As shown, the ASIC chip 15 is connected to the metallized through hole 121 through a second gold wire 133. For example, the second gold wire 133 is located on one side of the ASIC chip 15 that is perpendicular to the thickness direction. One end of the second gold wire 133 is welded to the output end of the ASIC chip 15, and the other end is welded to the metallized through hole 121.

[0060] The second gold wire 133 can adapt to different installation positions, which reduces the requirement on the assembly accuracy of the ASIC chip 15 and makes it easier to connect the ASIC chip 15 with the metallized through hole 121 .

[0061] In one example, the ASIC chip 15 is fixed in the receiving cavity by an adhesive. For example, the adhesive is a commonly used glue 132 in the art. Those skilled in the art can select according to actual needs.

[0062] In an example, Figure 1As shown, 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 body 11. The second layer includes the second substrate 13.

[0063] 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. When assembling, 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 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.

[0064] In an example, Figure 4 As shown, during assembly, first, the ASIC chip 15 is fixed on the first substrate 12 by a first adhesive and connected to the MEMS acoustic chip 14. For example, the first adhesive is glue 132. First, the first adhesive is applied to the ASIC chip 15 and / or the first substrate 12, and then the ASIC chip 15 is bonded to the first substrate 12. The ASIC chip 15 is connected to the metallized through-hole 121 on the first substrate 12 through a pad 122 or a second metal wire. The MEMS acoustic chip 14 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 MEMS acoustic chip 14 and the ASIC chip 15 form an assembly with the first substrate 12. This makes the position of the MEMS acoustic chip 14 and the ASIC chip 15 on the substrate assembly more precise.

[0065] Then, a second adhesive is disposed on the second substrate 13. For example, the second adhesive is glue 132.

[0066] 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 adhesive 132.

[0067] In an example, Figure 3 As shown, the packaging 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 filters 16 can all play a filtering effect.

[0068] For example, the filter 16 is disposed in the cavity 111. The filter 16 is connected to the output end of the ASIC chip 15. In this way, the filter 16 can effectively filter out the interference of the radio frequency interference entering the ASIC chip 15 through the output end to the MEMS acoustic chip 14. The filter 16 is connected to the power supply end 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.

[0069] Alternatively, the filter 16 is 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 effect on adjusting the sound pickup effect.

[0070] In an example, Figure 2 As shown, the filter 16 is connected to the external device through the conductor layer 123 of the housing, and the filter 16 is connected to the ASIC chip 15 through the metallized through hole 121. For example, the filter 16 is connected to the conductive layer through the pad 122, and is connected to the metallized through hole 121 through the conductor layer 123, and is connected to the ASIC chip 15 through the metallized through hole 121 and the pad 122. Compared with the connection through the metal wire, this setting will not form an antenna effect. That is, the metal wire itself can act as an antenna and thus generate secondary radiation, and the connection with the ASIC through the pad 122 and the conductor layer 123 will not generate secondary radiation.

[0071] According to another embodiment of the present disclosure, an electronic device is provided, which includes a device housing and the above-mentioned microphone packaging structure, wherein the microphone packaging structure is disposed in the device housing.

[0072] The electronic device has the characteristic of good sound pickup effect.

[0073] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A microphone packaging structure, characterized in that: include: A shell, wherein a cavity is formed inside the shell, wherein at least a portion of the shell includes a first layer and a second layer arranged along a thickness direction, and a receiving cavity is formed between the first layer and the second layer; A MEMS acoustic chip, wherein the MEMS acoustic chip is disposed in the cavity; and An ASIC chip, wherein the ASIC chip is disposed in the accommodating cavity and connected to the MEMS acoustic chip; The shell includes a substrate assembly, the substrate assembly includes a first substrate and a second substrate, the first layer includes the first substrate, the second layer includes the second substrate, at least one of the first substrate and the second substrate is a PCB, and at least a portion of a conductor layer of the PCB is opposite to the ASIC chip.

2. The microphone packaging structure according to claim 1, characterized in that: The first layer is close to the cavity, a metallized through hole is arranged in the first layer, and the MEMS acoustic chip is connected to the ASIC chip through the metallized through hole.

3. The microphone packaging structure according to claim 2, characterized in that: The MEMS acoustic chip is connected to the metallized through hole through a first gold wire; or The MEMS acoustic chip is flipped inside the shell and connected to the metallized through hole through the conductor layer of the shell.

4. The microphone packaging structure according to claim 2, characterized in that: The ASIC chip is connected to the metallized through hole through a second gold wire or a pad.

5. The microphone packaging structure according to claim 1, characterized in that: The ASIC chip is fixed in the accommodation cavity by means of an adhesive.

6. The microphone packaging structure according to claim 1, characterized in that: The shell comprises a cover body, the cover body and the substrate assembly enclose the cavity, and the first substrate is connected to the cover body.

7. The microphone packaging structure according to claim 6, characterized in that: During assembly, First, the ASIC chip is fixed on the first substrate by a first adhesive and connected to the MEMS acoustic chip; Then, disposing a second adhesive 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 1, characterized in that: The first layer and the second layer are connected together by bonding, clamping or welding.

9. The microphone packaging structure according to claim 1, characterized in that: It also includes a filter, which is arranged in the cavity or buried in the wall of the shell, and is connected to the ASIC chip.

10. The microphone packaging structure according to claim 9, characterized in that: 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 metallized through hole.

11. An electronic device, characterized in that: It comprises a device housing and a microphone packaging structure as described in any one of claims 1 to 10, wherein the microphone packaging structure is arranged in the device housing.

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