CN213186551U

CN213186551U - Packaging structure and electronic equipment of MEMS microphone

Info

Publication number: CN213186551U
Application number: CN202022577545.2U
Authority: CN
Inventors: 齐利克
Original assignee: Qingdao Goertek Intelligent Sensor Co Ltd
Current assignee: Qingdao Goertek Intelligent Sensor Co Ltd
Priority date: 2020-11-09
Filing date: 2020-11-09
Publication date: 2021-05-11
Anticipated expiration: 2030-11-09

Abstract

The utility model discloses a packaging structure and electronic equipment of MEMS microphone, wherein, packaging structure of MEMS microphone includes shroud, base plate, at least two-layer solder mask and ASIC chip, the base plate closes with the shroud encloses and forms the holding chamber, the base plate sets up with the sound hole of holding chamber intercommunication; the solder mask layer is arranged on the surface of the substrate facing the cover cap in a laminated mode, and is provided with avoidance holes communicated with the sound holes; the MEMS chip is arranged on the solder mask layer and covers the avoidance hole; the ASIC chip is arranged in the accommodating cavity and is electrically connected with the substrate and the sensor chip respectively. The utility model discloses technical scheme's MEMS microphone's packaging structure can improve the frequency response curve, improves high frequency tone quality.

Description

Packaging structure and electronic equipment of MEMS microphone

Technical Field

The utility model relates to a microphone technical field, in particular to packaging structure and electronic equipment of MEMS microphone.

Background

The MEMS microphone is a microphone manufactured by a Micro-Electro-Mechanical Systems (MEMS) process. This microphone contains two chips: the MEMS microphone comprises an MEMS chip and an Application Specific Integrated Circuit (ASIC) chip, wherein the two chips are packaged in a packaging structure consisting of a substrate and a shell, the MEMS chip is arranged on the inner side of a printed Circuit board, a vibrating diaphragm is arranged on the MEMS chip, a cavity between the MEMS chip and the inner side of the substrate can be called a front cavity of the MEMS microphone, and the rest of a sealed cavity can be called a rear cavity of the MEMS microphone. The front cavity structure of the MEMS microphone is related to the frequency response of a product, and the current front cavity structure is not reasonable enough, so that the frequency response and the tone quality of the product are influenced.

SUMMERY OF THE UTILITY MODEL

The main object of the present invention is to provide an encapsulating structure of MEMS microphone, aiming at obtaining an encapsulating structure which increases the front cavity of the microphone and improves the sound quality effect.

In order to achieve the above object, the present invention provides a package structure of a MEMS microphone, which includes:

a cover;

the base plate and the cover enclose to form an accommodating cavity, and the base plate is provided with a sound hole communicated with the accommodating cavity;

the solder mask layers are stacked on the surface of the base plate facing the cover cap and provided with avoidance holes communicated with the sound holes;

the MEMS chip is arranged on the solder mask layer and covers the avoidance hole; and

and the ASIC chip is arranged in the accommodating cavity and is electrically connected with the substrate and the sensor chip respectively.

In an optional embodiment, the solder mask layer comprises a first solder mask layer and a second solder mask layer, the first solder mask layer covers the substrate, the second solder mask layer surrounds the sound hole, the MEMS chip is disposed on the second solder mask layer, and the ASIC chip is disposed on the first solder mask layer.

In an optional embodiment, the MEMS chip includes a substrate and a diaphragm assembly, the substrate is provided with a through hole communicating with the avoiding hole, the diaphragm assembly is provided with an end of the substrate deviating from the base plate and covering the through hole, the opening size of the avoiding hole is less than or equal to the opening size of the through hole near one side of the base plate.

In an optional embodiment, the opening shape of the avoiding hole matches the opening shape of the through hole.

In an optional embodiment, a projected area of the second solder resist layer on the substrate is greater than or equal to a projected area of the substrate on the substrate.

In an optional embodiment, the opening size of the avoiding hole is larger than the opening size of the sound hole.

In an alternative embodiment, the MEMS chip is electrically connected to the ASIC chip by a metal wire.

In an optional embodiment, the ASIC chip is attached to the substrate; or, the ASIC chip is welded on the substrate.

In an optional embodiment, a solder foot or a solder pad is arranged on a surface of the substrate facing away from the accommodating cavity.

The utility model discloses provide an electronic equipment again, include the casing and locate MEMS microphone's in the casing packaging structure, MEMS microphone's packaging structure be as above MEMS microphone's packaging structure.

The utility model discloses technical scheme's packaging structure of MEMS microphone includes base plate and shroud, MEMS chip and ASIC chip, and base plate and shroud enclose to close the holding chamber that forms and can provide shielding space for ASIC chip and MEMS chip to effectively prevent external component and signal to cause the influence to it. The sound hole of intercommunication holding chamber is seted up to the base plate, can be so that outside sound passes through the sound hole and gets into, and then can convert acoustic signal into the signal of telecommunication through acting on the MEMS chip to through the processing and the amplification of ASIC chip, realize the function of receiving sound then. Meanwhile, at least two layers of solder masks are arranged between the substrate and the MEMS chip, and the solder masks are provided with avoidance holes communicated with the sound holes, so that the spacing space between the MEMS chip and the substrate is effectively increased, the volume of a front cavity for forming the sound cavity is increased, the low frequency can be effectively attenuated, and the high-frequency sound quality is improved; meanwhile, the frequency response curve can be improved, and the tone quality effect is further improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a longitudinal sectional view of an embodiment of the MEMS microphone package structure of the present invention;

fig. 2 is a cross-sectional view of a package structure of the MEMS microphone shown in fig. 1.

The reference numbers illustrate:

the objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

In the present application, unless expressly stated or limited otherwise, the terms "connected" and "fixed" are to be construed broadly, e.g., "fixed" may be fixedly connected or detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In addition, descriptions in the present application as to "first", "second", and the like are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The utility model provides a packaging structure 100 of MEMS microphone.

Referring to fig. 1 and fig. 2, in an embodiment of the present invention, a package structure 100 of a MEMS microphone includes a cover cap 30 and a substrate 10, the substrate 10 and the cover cap 30 enclose to form a containing cavity 10a, and the substrate 10 is provided with a sound hole 11 communicated with the containing cavity 10 a;

at least two solder resist layers, wherein the solder resist layers are stacked on the surface of the substrate 10 facing the cover cap 30 and are provided with avoidance holes 50a communicated with the sound holes 11;

the MEMS chip 70 is arranged on the solder mask layer and covers the avoidance hole 50 a; and

the ASIC chip 90 is disposed in the accommodating cavity 10a, and the ASIC chip 90 is electrically connected to the substrate 10 and the sensor chip, respectively.

In this embodiment, the package structure 100 of the MEMS microphone includes a cover cap 30 and a substrate 10, wherein the substrate 10 is a PCB board printed with a circuit to implement a corresponding electrical function, and the design can be selected according to actual needs. And the PCB board can include copper foil layer 15, semi-curing layer and buried layer from top to bottom in proper order, certainly, the PCB board of different specifications has different number of piles, can select according to actual need, for example, topmost copper foil layer 15 also can not have. In addition, a solder mask is also arranged on the surface of the copper foil layer 15, and the solder mask is a solder mask which is a green surface layer displayed on a printed circuit board and can prevent solder from overflowing and avoid causing short circuit; and the performance of the circuit board can be effectively protected by moisture. The longitudinal section of the cover cap 30 is in a U-shaped configuration, the cover cap 30 can be a metal shell formed integrally or a non-metal shell coated with a metal material, the cover cap 30 encloses a closed accommodating cavity 10a with one end of the opening direction and the substrate 10, it can be understood that the cover cap 30 and the substrate 10 can be connected by conductive adhesive or solder paste, and the cover cap 30 and the substrate 10 can be electrically connected, so as to form a conductive shielding cavity, the MEMS chip 70 and the ASIC chip 90 are disposed in the accommodating cavity 10a, so as to prevent external electromagnetic interference, enhance the protection effect on the two, and ensure the conversion performance of the MEMS chip 70. Of course, the cover 30 can communicate with the substrate 10 through other conductive materials.

The shape of the structure enclosed by the cover 30 and the substrate 10 may be a cube, a cylinder, a sphere, or the like, and is not limited herein. Meanwhile, in order to fix the substrate 10 and the applied product or system and transmit the electrical signal, in an embodiment, the surface of the substrate 10 facing away from the accommodating cavity 10a is provided with a solder foot or a solder pad 13. The solder feet or the solder pads 13 can be conveniently welded on a main board circuit of a specific product through the SMT and other processes, and the number of the specific solder feet can be 3 or 4, so that the stability of structural connection and data transmission is improved.

In order to realize the sound receiving function of the MEMS chip 70, the substrate 10 is provided with a sound hole 11 to facilitate the inflow of the sound signal, and the MEMS chip 70 is used for sensing and detecting the sound signal flowing from the sound hole 11, converting the sound signal into an electrical signal for transmission, and transmitting the electrical signal to the ASIC chip 90; the ASIC chip 90 is used to provide a voltage to the MEMS chip 70, and process and amplify the signal output by the MEMS chip 70, so that the package structure 100 of the MEMS microphone provides a sound receiving function for the electronic device. Meanwhile, in order to increase the front cavity space formed by the MEMS chip 70 and the substrate 10, in this embodiment, at least one solder resist layer is further stacked on the solder resist layer, and the MEMS chip 70 is disposed on the second solder resist layer, so as to increase the vertical distance between the MEMS chip 70 and the substrate 10, and certainly, the solder resist layer disposed on the substrate 10 needs to be provided with an avoiding hole 50a communicated with the acoustic hole 11, so as to transmit the acoustic signal.

The utility model discloses technical scheme's packaging structure 100 of MEMS microphone includes base plate 10 and shroud 30, MEMS chip 70 and ASIC chip 90, and base plate 10 and shroud 30 enclose to close the holding chamber 10a that forms and can provide shielding space for ASIC chip 90 and MEMS chip 70 to effectively prevent external component and signal to cause the influence to it. The substrate 10 is provided with a sound hole 11 communicated with the accommodating cavity 10a, so that external sound can enter through the sound hole 11, the acoustic signal can be converted into an electric signal by acting on the MEMS chip 70, and the sound receiving function is realized by processing and amplifying the ASIC chip 90. Meanwhile, at least two layers of solder masks are arranged between the substrate 10 and the MEMS chip 70, and the solder masks are provided with avoidance holes 50a communicated with the sound holes 11, so that the spacing space between the MEMS chip 70 and the substrate 10 is effectively increased, the volume of a front cavity forming the sound cavity is increased, the low frequency can be effectively attenuated, and the high-frequency tone quality is improved; meanwhile, the frequency response curve can be improved, and the tone quality effect is further improved. And two stacked solder masks can be directly completed through one process, the assembly of other structures is not required to be increased, and the production efficiency is effectively improved.

In an alternative embodiment, the two solder resist layers include a first solder resist layer 51 and a second solder resist layer 53, the first solder resist layer 51 covers the substrate 10, the second solder resist layer 53 surrounds the acoustic hole 11, the MEMS chip 70 is disposed on the second solder resist layer 53, and the ASIC chip 90 is disposed on the first solder resist layer 51.

In this embodiment, when the package structure 100 of the MEMS microphone is provided with two solder resist layers, the two solder resist layers are sealed into the first solder resist layer 51 and the second solder resist layer 53, and the first solder resist layer 51 covers the substrate 10, that is, the solder resist layer added in the process of preparing the substrate 10 provides protection for the substrate 10. The second solder resist layer 53 is disposed around the acoustic hole 11, and provides a base for assembling the MEMS chip 70, and increases the height thereof, so that the front cavity space of the acoustic cavity can be increased. Meanwhile, the ASIC chip 90 is disposed on the first solder resist layer 51, so that the amount of the second solder resist layer 53 can be reduced, thereby saving the manufacturing time and material and reducing the cost. Specifically, the first solder resist layer 51 and the second solder resist layer 53 may be set to have a thickness equivalent to each other, thereby simplifying the manufacturing process and improving the production efficiency.

Of course, in other embodiments, three solder mask layers may be provided, that is, a third solder mask layer is further provided on the second solder mask layer 53.

In an optional embodiment, the MEMS chip 70 includes a substrate 71 and a diaphragm component 73, the substrate 71 is provided with a through hole 711 communicating with the avoiding hole 50a, the diaphragm component 73 is provided at one end of the substrate 71 deviating from the base plate 10 and covers the through hole 711, an opening size of the avoiding hole 50a is less than or equal to an opening size of the through hole 711 near one side of the base plate 10.

In this embodiment, the MEMS chip 70 includes a substrate 71 and a diaphragm assembly 73, the substrate 71 is generally made of a material such as single crystal silicon, polysilicon, or silicon nitride, and the substrate 71 is substantially square in external shape and may be connected to the second solder resist layer 53 through a glue. The substrate 71 is disposed around the periphery of the acoustic hole 11, and is provided with a through hole 711, the through hole 711 is communicated with the acoustic hole 11 through the avoiding hole 50a, and the three cooperate to form an acoustic cavity of the package structure 100 of the MEMS microphone, so that smoothness of sound transmission can be ensured. The diaphragm assembly 73 may be of a piezoelectric type or a capacitive type, and is not limited herein. For example, when the diaphragm assembly 73 is of a piezoelectric structure, it includes a diaphragm and piezoelectric materials disposed on two sides of the diaphragm, and the diaphragm is excited by a sound signal to vibrate the diaphragm, so that the pressure of the piezoelectric materials changes, and a corresponding electrical signal is output.

The MEMS chip 70 is electrically connected to the ASIC chip 90 through the diaphragm component 73, specifically, the MEMS chip 70 may be electrically connected to the ASIC chip 90 through a metal wire, that is, the diaphragm component 73 is electrically connected to the ASIC chip 90 through a metal wire, where the metal wire may be a gold wire or a copper wire, so as to effectively improve the stability of the electrical connection.

It can be understood that the opening size of the avoiding hole 50a is not too small, otherwise the space increasing effect on the front cavity of the acoustic cavity is not large, so in this embodiment, the opening size of the avoiding hole 50a is set to be larger than the opening size of the acoustic hole 11; meanwhile, the opening size of the avoiding hole 50a is not too large, otherwise, the opening size is not beneficial to supporting the MEMS chip 70, and here, the size of the avoiding hole 50a is set to be equal to or slightly smaller than the opening size of the through hole 711 near the substrate 10, so that the support of the second solder mask layer 53 on the substrate 71 is more stable, the front cavity space of the acoustic cavity is enlarged as much as possible, the frequency response curve is improved, and the tone quality is improved. The opening size of the avoidance hole 50a and the opening size of the through hole 711 are designed by simulation according to actual acoustic requirements.

In an alternative embodiment, the opening shape of the avoiding hole 50a matches the opening shape of the through hole 711. In this embodiment, the cross-sectional shape of the through hole 711 is circular, so the opening shape of the avoiding hole 50a is also circular, and correspondingly, the opening shape of the sound hole 11 is also circular, so that the peripheral wall of the sound cavity is a smooth arc surface, which effectively reduces the resistance to sound signals, thereby reducing the generation of noise. Here, the cross-sectional area of the through hole 711 shows a decreasing trend along the direction from the substrate 10 to the cover 30, but of course, in other embodiments, the cross-sectional area of the through hole 711 may be gradually decreased or constant, and is not limited herein. Further, the cross-section of the through hole 711, the relief hole 50a, and the sound hole 11 may be square or other polygonal shapes.

In an alternative embodiment, a projected area of the second solder resist layer 53 on the substrate 10 is greater than or equal to a projected area of the substrate 71 on the substrate 10.

In this embodiment, the projection area of the second solder resist layer 53 on the substrate 10 is set to be greater than or equal to the projection area of the substrate 71 on the substrate 10, so that on one hand, the dispensing processing can be conveniently performed on the second solder resist layer 53, and the situation that the glue on the outer periphery of the substrate 71 overflows and flows onto the ASIC chip 90, and then the performance of the ASIC chip is affected is avoided; on the other hand, the substrate 71 can be stably supported, and the stability of fixing the MEMS chip 70 is ensured.

In an alternative embodiment, the ASIC chip 90 is attached to the substrate 10; alternatively, the ASIC chip 90 is soldered to the substrate 10.

In this embodiment, since the substrate 10 is coated with the solder resist layer, specifically, the first solder resist layer 51, the ASIC chip 90 is attached to the first solder resist layer 51 by glue, thereby realizing a stable connection structure; the ASIC chip 90 is then electrically connected to the substrate 10 by metal wires, which may be gold wires, copper wires, or the like. Of course, in other embodiments, the ASIC chip 90 may be fixed to the substrate 10 by opening a hole in the first solder resist layer 51 and soldering with a solder ball.

The utility model provides an electronic equipment (not shown in the drawing) again, include the casing and locate packaging structure 100 of MEMS microphone in the casing, packaging structure 100's of MEMS microphone concrete structure refers to above-mentioned embodiment, because this electronic equipment's MEMS microphone packaging structure 100 has adopted all technical scheme of above-mentioned all embodiments, consequently has all beneficial effects that the technical scheme of above-mentioned embodiment brought at least, and it is here no longer repeated one by one.

The electronic device may be a wearable electronic device, such as a smart watch or a bracelet, or may be a mobile terminal, such as a mobile phone or a notebook computer, or other devices that need to have an audio-electrical conversion function, which is not limited herein.

The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structure changes made by the contents of the specification and the drawings under the inventive concept of the present invention, or the direct/indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A package structure of a MEMS microphone, comprising:

a cover;

2. The packaging structure of the MEMS microphone according to claim 1, wherein the two solder resist layers include a first solder resist layer and a second solder resist layer, the first solder resist layer covers the substrate, the second solder resist layer is disposed around the acoustic hole, the MEMS chip is disposed on the second solder resist layer, and the ASIC chip is disposed on the first solder resist layer.

3. The MEMS microphone packaging structure of claim 2, wherein the MEMS chip comprises a substrate and a diaphragm assembly, the substrate is provided with a through hole communicating with the avoiding hole, the diaphragm assembly is disposed at an end of the substrate away from the substrate and covers the through hole, and an opening size of the avoiding hole is smaller than or equal to an opening size of the through hole near one side of the substrate.

4. The packaging structure of the MEMS microphone according to claim 3, wherein an opening shape of the avoiding hole matches an opening shape of the through hole.

5. The packaging structure of the MEMS microphone according to claim 4, wherein a projected area of the second solder resist layer on the substrate is equal to or larger than a projected area of the substrate on the substrate.

6. The packaging structure of a MEMS microphone according to any one of claims 1 to 5, wherein an opening size of the avoiding hole is larger than an opening size of the acoustic hole.

7. The packaging structure of the MEMS microphone of claim 1, wherein the MEMS chip is electrically connected to the ASIC chip by a metal wire.

8. The package structure of the MEMS microphone according to claim 1, wherein the ASIC chip is attached to the substrate; or, the ASIC chip is welded on the substrate.

9. The packaging structure of the MEMS microphone as defined by claim 1 wherein the surface of the substrate facing away from the cavity is provided with solder fillets or pads.

10. An electronic device, comprising a housing and a package structure of a MEMS microphone arranged in the housing, wherein the package structure of the MEMS microphone is the package structure of the MEMS microphone according to any one of claims 1 to 9.