Microphone packaging structure and microphone system

Abstract

The present invention discloses a microphone packaging structure and a microphone system. The microphone packaging structure includes a substrate, a MEMS chip, an ASIC chip and a protective shell; wherein the MEMS chip and the ASIC chip are mounted on the substrate, the MEMS chip is electrically connected to the ASIC chip, and the ASIC chip is electrically connected to the substrate; the MEMS chip is used to convert external sound signals into electrical signals, and the ASIC chip is used to process electrical signals; the protective shell is located on the substrate and covers the MEMS chip and the ASIC chip; the protective shell includes a through hole; the substrate includes at least two hollow chambers, and at least two hollow chambers are connected to the back cavity of the MEMS chip. The technical solution provided by the embodiment of the present invention improves the signal-to-noise ratio of the microphone packaging structure.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of microphone technology, and in particular to a microphone packaging structure and a microphone system. Background Art

[0002] The volume of the MEMS microphone package is much smaller than that of the traditional electret microphone package, which is conducive to the portable development of the microphone system and is highly favored by users.

[0003] At present, the sound input modes of MEMS microphones include front-input sound and back-input sound. Among them, the signal-to-noise ratio of the front-input sound product is 3 to 4 dB lower than that of the back-input sound product due to the packaging structure, and it is difficult to improve to a higher level due to structural limitations. Summary of the invention

[0004] The invention provides a microphone packaging structure and a microphone system to improve the signal-to-noise ratio of the microphone packaging structure.

[0005] In a first aspect, an embodiment of the present invention provides a microphone packaging structure, including:

[0006] Substrate, MEMS chip, ASIC chip and protective shell;

[0007] The MEMS chip and the ASIC chip are mounted on the substrate, the MEMS chip is electrically connected to the ASIC chip, and the ASIC chip is electrically connected to the substrate; the MEMS chip is used to convert the external sound signal into an electrical signal, and the ASIC chip is used to process the electrical signal;

[0008] The protective shell is located on the substrate and covers the MEMS chip and the ASIC chip; the protective shell includes a through hole;

[0009] The substrate includes at least two hollow chambers, and the at least two hollow chambers are communicated with the back cavity of the MEMS chip.

[0010] In a second aspect, an embodiment of the present invention further provides a microphone system, comprising the microphone packaging structure described in the first aspect.

[0011] The microphone packaging structure provided by an embodiment of the present invention includes a substrate, a MEMS chip, an ASIC chip and a protective shell, wherein the MEMS chip and the ASIC chip are installed on the substrate, the MEMS chip is electrically connected to the ASIC chip, the ASIC chip is electrically connected to the substrate, the MEMS chip is used to convert external sound signals into electrical signals, the ASIC chip is used to process electrical signals, the protective shell is located on the substrate and covers the MEMS chip and the ASIC chip, the protective shell includes a through hole, the substrate includes at least two hollow chambers, at least two hollow chambers are connected to the back cavity of the MEMS chip, the setting of at least two central control chambers increases the back cavity volume of the MEMS chip, thereby improving the signal-to-noise ratio of the microphone, and the spacer between the at least two central control chambers plays a supporting role, avoiding the collapse of the hollow chamber in the substrate pressing process and the MEMS chip mounting process, and improving the strength of the substrate and the microphone packaging structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0013] Figure 1 is a schematic diagram of a microphone packaging structure provided by an embodiment of the present invention;

[0014] Figure 2 is a schematic diagram of a top view structure of a substrate provided by an embodiment of the present invention;

[0015] Figure 3 is along Figure 2 A schematic diagram of the cross-sectional structure of the middle dotted line AA;

[0016] Figure 4 is along Figure 2 A schematic diagram of the cross-sectional structure of the middle dotted line BB;

[0017] Figure 5 is a schematic diagram of another microphone packaging structure provided by an embodiment of the present invention;

[0018] Figure 6 It is a structural schematic diagram of a microphone system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation method, structure, characteristics and effects of a microphone packaging structure and a microphone system proposed in accordance with the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0020] An embodiment of the present invention provides a microphone packaging structure, including:

[0021] Substrate, MEMS chip, ASIC chip and protective shell;

[0022] The MEMS chip and the ASIC chip are mounted on the substrate, the MEMS chip is electrically connected to the ASIC chip, and the ASIC chip is electrically connected to the substrate; the MEMS chip is used to convert the external sound signal into an electrical signal, and the ASIC chip is used to process the electrical signal;

[0023] The protective shell is located on the substrate and covers the MEMS chip and the ASIC chip; the protective shell includes a through hole;

[0024] The substrate includes at least two hollow chambers, and the at least two hollow chambers are communicated with the back cavity of the MEMS chip.

[0025] The microphone packaging structure provided by an embodiment of the present invention includes a substrate, a MEMS chip, an ASIC chip and a protective shell, wherein the MEMS chip and the ASIC chip are installed on the substrate, the MEMS chip is electrically connected to the ASIC chip, the ASIC chip is electrically connected to the substrate, the MEMS chip is used to convert external sound signals into electrical signals, the ASIC chip is used to process electrical signals, the protective shell is located on the substrate and covers the MEMS chip and the ASIC chip, the protective shell includes a through hole, the substrate includes at least two hollow chambers, at least two hollow chambers are connected to the back cavity of the MEMS chip, the setting of at least two central control chambers increases the back cavity volume of the MEMS chip, thereby improving the signal-to-noise ratio of the microphone, and the spacer between the at least two central control chambers plays a supporting role, avoiding the collapse of the hollow chamber in the substrate pressing process and the MEMS chip mounting process, and improving the strength of the substrate and the microphone packaging structure.

[0026] The above is the core idea of ​​the present application. The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented using other embodiments different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention in detail, for the sake of convenience, the schematic diagrams showing the device structure are not partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and height should be included.

[0029] Figure 1 Schematic diagram of a microphone packaging structure provided by an embodiment of the present invention. Figure 1 As shown, the microphone packaging structure includes a substrate 100 , a MEMS chip 200 , an ASIC chip 300 and a protective shell 400 .

[0030] The MEMS chip 200 and the ASIC chip 300 are mounted on the substrate 100, the MEMS chip 200 is electrically connected to the ASIC chip 300, the ASIC chip 300 is electrically connected to the substrate 100, the MEMS chip 200 is used to convert external sound signals into electrical signals, and the ASIC chip is used to process electrical signals. The protective shell 400 is located on the substrate 100 and covers the MEMS chip 200 and the ASIC chip 300, the protective shell 400 includes a through hole 410, and the substrate 100 includes at least two hollow chambers 110, and the at least two hollow chambers 110 are connected to the back cavity 210 of the MEMS chip 200.

[0031] Specifically, Figure 2 It is a schematic diagram of a top view structure of a substrate provided by an embodiment of the present invention. Figure 3 is along Figure 2 Schematic diagram of the cross-sectional structure of the dotted line AA. Figure 4 is along Figure 2 The cross-sectional structure diagram of the dotted line BB is shown in FIG. Figure 2 , Figure 3 and Figure 4 As shown, the substrate includes three hollow chambers 110, and the three hollow chambers 110 are all connected to the opening 101 on the upper surface of the substrate 100. During the installation of the MEMS chip, the MEMS chip covers the opening 101, and the MEMS chip is supported by the spacers between the hollow chambers 110. The downward pressure acting on the MEMS chip will not easily cause the hollow chamber 110 to collapse. At the same time, during the substrate processing, the hollow chamber 110 will not collapse due to the support of the spacers.

[0032] It should be noted that the MEMS chip includes a vibrating film. The sound generated by the outside world can reach the vibrating film through the through holes on the protective shell, changing the distance between the vibrating film and the back plate, thereby forming a capacitance change. The ASIC chip converts the capacitance change into a voltage signal change, which is then amplified and output. Specifically, the voltage signal can be transmitted to the outside of the microphone packaging structure through the line on the substrate.

[0033] It should also be noted that Figure 2 The three circular hollow chambers are taken as an example for illustrative description only and are not limiting. In other implementations of this embodiment, the number and shape of the hollow chambers may be other cases.

[0034] The microphone packaging structure provided in this embodiment includes a substrate, a MEMS chip, an ASIC chip and a protective shell, wherein the MEMS chip and the ASIC chip are installed on the substrate, the MEMS chip is electrically connected to the ASIC chip, the ASIC chip is electrically connected to the substrate, the MEMS chip is used to convert external sound signals into electrical signals, the ASIC chip is used to process electrical signals, the protective shell is located on the substrate and covers the MEMS chip and the ASIC chip, the protective shell includes a through hole, the substrate includes at least two hollow chambers, at least two hollow chambers are connected to the back cavity of the MEMS chip, the setting of at least two central control chambers increases the back cavity volume of the MEMS chip, thereby improving the signal-to-noise ratio of the microphone, and the spacer between the at least two central control chambers plays a supporting role, avoiding the collapse of the hollow chamber in the substrate pressing process and the MEMS chip mounting process, and improving the strength of the substrate and the microphone packaging structure.

[0035] Continue to see Figure 1 The substrate 100 includes a first sub-substrate 121 and a second sub-substrate 122 stacked in sequence. The first sub-substrate 121 is located on a side of the second sub-substrate 122 close to the protective shell 400. The first sub-substrate 121 includes an opening 102, and the second sub-substrate 122 includes at least two grooves 103. The at least two grooves 103 and the first sub-substrate 121 form at least two hollow chambers 110. The at least two central control chambers 110 are connected to the back cavity 210 of the MEMS chip through the opening 102.

[0036] In this way, the preparation process of the large-volume hollow chamber 110 with a small opening is simpler, and only conventional groove preparation and plate pasting are required, without the need for complex processes, and the size of the hollow chamber is more controllable.

[0037] Figure 5 FIG. 1 is a schematic diagram of another microphone packaging structure provided by an embodiment of the present invention. Figure 5 As shown, in Figure 1 On the basis of the MEMS chip 200 and the substrate 100, a padding ring 500 is further arranged between the MEMS chip 200 and the substrate 100, and the back cavity 210 of the MEMS chip 200, the internal space of the padding ring 500 and at least two hollow chambers 110 are connected.

[0038] It should be noted that the padding ring 500 is a ring structure, which can further increase the volume of the back cavity 210 of the MEMS chip 200, thereby achieving a higher signal-to-noise ratio.

[0039] It is understandable that the electrical signal transmission between the MEMS chip 200 and the ASIC chip 300 is realized through the wire 600 between the two, and there is no electrical signal transmission between the two and the substrate and the padding ring 500. Therefore, the material of the padding ring 500 can be a conductive material or a non-conductive material, and this embodiment does not specifically limit this. In addition, the height of the padding ring 500 can be reasonably set according to actual needs.

[0040] Optionally, the shape of the padding ring 500 is the same as the outer edge shape of the MEMS chip 200. In this way, the cross-sectional size of the internal space in the padding ring 500 communicating with the back cavity 210 of the MEMS chip 200 is the largest, which is conducive to increasing the size of the back cavity 210 of the MEMS chip 200.

[0041] For example, the material of the protective shell 400 may be metal.

[0042] It should be noted that metal has a relatively high strength and can withstand relatively large impacts, thereby preventing external forces from damaging the MEMS chip 200 and the ASIC chip 300 .

[0043] In this embodiment, if Figure 5 As shown, the MEMS chip 200 is electrically connected to the ASIC chip 300 through a wire 600 , and the ASIC chip 300 is electrically connected to the substrate 100 through a wire 600 .

[0044] It should be noted that the connection process between the wire 600 and the chip is simple and can be achieved only through conventional welding process with good reliability. In addition, the setting of the conductor 600 simplifies the circuit structure on the substrate 100, thereby simplifying the preparation process of the substrate.

[0045] Optionally, an adhesive film may be provided on the surface of the ASIC chip 300 away from the substrate 100 .

[0046] It should be noted that the raw material of the adhesive film may be glue, which can protect the solder joints in the ASIC chip and prevent dust.

[0047] For example, the shape of the through hole 410 may be circular.

[0048] It should be noted that the process of forming circular through holes on metal layers in existing production lines is mature, and setting the shape of through hole 410 to be circular is conducive to simplifying the preparation process of through hole 410.

[0049] Figure 6 Schematic diagram of a microphone system provided by an embodiment of the present invention. Figure 6As shown, the microphone system 10 includes the microphone packaging structure 11 provided by any embodiment of the present invention. The microphone system 10 provided by an embodiment of the present invention includes the microphone packaging structure 11 of any embodiment of the present invention, has the technical features of the microphone packaging structure 11 provided by any embodiment of the present invention, and has the same or corresponding beneficial effects as the microphone packaging structure 11 it includes, which will not be repeated here.

[0050] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A microphone packaging structure, characterized in that: include: Substrate, MEMS chip, ASIC chip and protective shell; The MEMS chip and the ASIC chip are mounted on the substrate, the MEMS chip is electrically connected to the ASIC chip, and the ASIC chip is electrically connected to the substrate; the MEMS chip is used to convert the external sound signal into an electrical signal, and the ASIC chip is used to process the electrical signal; The protective shell is located on the substrate and covers the MEMS chip and the ASIC chip; the protective shell includes a through hole; The substrate comprises at least two hollow chambers, and the at least two hollow chambers are connected to the back cavity of the MEMS chip; The substrate includes a first sub-substrate and a second sub-substrate stacked in sequence, the first sub-substrate is located on a side of the second sub-substrate close to the protective shell; the first sub-substrate includes an opening, the second sub-substrate includes at least two grooves, the at least two grooves and the first sub-substrate constitute the at least two hollow chambers, the at least two hollow chambers are separated by a spacer, and the at least two central control chambers are connected to the back cavity of the MEMS chip through the opening.

2. The microphone packaging structure according to claim 1, characterized in that: A padding ring is further arranged between the MEMS chip and the substrate, and the back cavity of the MEMS chip, the inner space of the padding ring and the at least two hollow chambers are connected.

3. The microphone packaging structure according to claim 2, characterized in that: The shape of the pad ring is the same as the shape of the outer edge of the MEMS chip.

4. The microphone packaging structure according to claim 1, characterized in that: The material of the protective shell is metal.

5. The microphone packaging structure according to claim 1, characterized in that: The MEMS chip is electrically connected to the ASIC chip via a wire, and the ASIC chip is electrically connected to the substrate via a wire.

6. The microphone packaging structure according to claim 1, characterized in that: An adhesive film is arranged on the surface of the ASIC chip away from the substrate.

7. The microphone packaging structure according to claim 1, characterized in that: The through hole is circular in shape.

8. A microphone system, characterized in that: Comprising the microphone packaging structure as described in any one of claims 1-7.

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