Dust-proof structure for MEMS devices and MEMS microphone packaging structure

Abstract

The present invention discloses a dustproof structure for a MEMS device and a MEMS microphone packaging structure. The dustproof structure for a MEMS device comprises a mesh membrane and a carrier. The mesh membrane has a fixed connection area, a buffer area and a sound-transmitting area. The buffer area surrounds the sound-transmitting area, the fixed connection area surrounds the buffer area, the fixed connection area is located at the edge of the mesh membrane, and a through hole penetrating the mesh membrane is provided on the buffer area; the carrier has a through opening, the carrier is connected to one side of the fixed connection area, and the opening corresponds to the positions of the buffer area and the sound-transmitting area.

Description

Technical Field

[0001] The present invention belongs to the technical field of acoustic-electric conversion, and in particular, relates to a dustproof structure for a MEMS device and a MEMS microphone packaging structure. Background Art

[0002] With the rapid development of electroacoustic technology, various electroacoustic products emerge in an endless stream. Microphone, as a transducer device that converts sound signals into electrical signals, is one of the most important devices in electroacoustic products. Nowadays, microphones have been widely used in many different types of electronic products such as mobile phones, tablets, laptops, VR devices, AR devices, and smart wearables. In recent years, the design of microphone packaging structure has become the focus and hot spot of research for technicians in this field.

[0003] The existing microphone packaging structure is usually composed of a housing with a housing cavity, in which microphone devices (such as MEMS chips and ASIC chips) and other components are fixed; and a sound hole is also provided on the housing. Therefore, it is found in long-term applications that dust, impurities and other particles and foreign objects from the outside are easily introduced into the microphone's housing cavity through the sound hole. These particles and foreign objects from the outside will cause certain damage to the microphone devices and other components in the housing cavity, and ultimately affect the acoustic performance and service life of the microphone.

[0004] In response to the above technical problems, the solution currently adopted is usually to set a corresponding isolation component on the sound hole of the microphone packaging structure to block the entry of external particles, foreign matter, etc. The existing isolation component generally includes a support part and an isolation mesh. When using the isolation component, the isolation component is installed on the sound hole. However, due to the differences in size, material, structure, etc. between the support part and the isolation mesh of the existing isolation component, a certain internal stress difference is likely to be generated at the connection position between the two; especially during hot pressing, due to the different thermal expansion coefficients of the support part and the isolation mesh, there is a difference in the deformation after heating. The above factors will cause the mesh on the isolation mesh to have folds or wrinkles, and the mesh cannot be guaranteed to be in a flat state, which will in turn cause the quality of the product to decline and even affect the airflow at the mesh. Summary of the invention

[0005] An object of the present invention is to provide a dustproof structure for a MEMS device and a MEMS microphone packaging structure.

[0006] According to a first aspect of the present invention, there is provided a dustproof structure for a MEMS device, comprising:

[0007] A mesh membrane, wherein the mesh membrane has a fixed connection area, a buffer area and a sound-transmitting area, wherein the buffer area surrounds the sound-transmitting area, the fixed connection area surrounds the buffer area, the fixed connection area is located at the edge of the mesh membrane, and the buffer area is provided with a through hole penetrating the mesh membrane;

[0008] A carrier having a through opening, the carrier is connected to one side of the fixed connection area, and the opening corresponds to the positions of the buffer area and the sound-transmitting area.

[0009] Optionally, the sound-transmitting area is made of an isolation net, and the isolation net is configured to allow sound to pass through.

[0010] Optionally, the isolation net is a non-woven fabric of organic material or a metal screen.

[0011] Optionally, a plurality of the through holes are provided on the buffer area, and the plurality of the through holes are distributed along a region surrounding the sound-transmitting area.

[0012] Optionally, the through hole is a circular hole.

[0013] Optionally, the through hole is an elliptical hole.

[0014] Optionally, the width of the buffer area is smaller than the width of the fixed connection area.

[0015] Optionally, the buffer area is made of the same material as the fixed connection area.

[0016] Optionally, the average thickness of the grid film is in the range of 0.3 μm to 1.2 μm.

[0017] According to another aspect of the present invention, a MEMS microphone packaging structure is provided, comprising:

[0018] A shell having a receiving cavity, wherein a sound hole is provided on the shell, and the sound hole connects the inside and the outside of the shell;

[0019] A microphone device, wherein the microphone device is fixedly disposed in the housing;

[0020] In the dustproof structure as described above, the carrier is fixedly connected to the housing;

[0021] The mesh membrane closes the sound hole; and / or the mesh membrane is spaced between the sound hole and the microphone device.

[0022] One technical effect of the present invention is that the dust-proof structure for MEMS devices provided by an embodiment of the present invention, by setting a buffer zone between the sound-transmitting area and the fixed connection area on the mesh membrane, the buffer zone is provided with a through hole penetrating the mesh membrane, so that when the fixed connection area of ​​the mesh membrane is connected to the carrier, the buffer zone can release stress and alleviate deformation, so that the sound-transmitting area of ​​the mesh membrane can basically maintain a flat state, avoiding the phenomenon of wrinkles on the sound-transmitting area.

[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 A schematic diagram of a dustproof structure for a MEMS device provided in an embodiment of the present invention Figure 1 ;

[0026] Figure 2 A schematic diagram of a dustproof structure for a MEMS device provided in an embodiment of the present invention Figure 2 ;

[0027] Figure 3 A schematic diagram of a dustproof structure for a MEMS device provided in an embodiment of the present invention Figure 3 ;

[0028] Figure 4 A schematic diagram of a dustproof structure for a MEMS device provided in an embodiment of the present invention Figure 4 ;

[0029] Figure 5 A schematic diagram of a MEMS microphone packaging structure provided by an embodiment of the present invention Figure 1 ;

[0030] Figure 6 A schematic diagram of a MEMS microphone packaging structure provided by an embodiment of the present invention Figure 2 ;

[0031] Figure 7 A schematic diagram of a MEMS microphone packaging structure provided by an embodiment of the present invention Figure 3 ;

[0032] Figure 8 A schematic diagram of a MEMS microphone packaging structure provided by an embodiment of the present invention Figure 4 ;

[0033] Fig. 9A schematic diagram of a MEMS microphone packaging structure provided by an embodiment of the present invention Figure 5 . DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] refer to Figure 1 , Figure 2 As shown, an embodiment of the present invention provides a dustproof structure for a MEMS device, which can be applied to, for example, a MEMS microphone packaging structure. The dustproof structure can effectively block external particles and foreign matter from entering the interior of the microphone packaging structure through the sound holes on the microphone packaging structure, thereby effectively protecting the components inside the microphone to avoid affecting the acoustic performance and service life of the microphone. The dustproof structure includes a mesh membrane 1 and a carrier 2, wherein the mesh membrane 1 has a fixed connection area 11, a buffer area 12 and a sound-transmitting area 13, wherein the buffer area 12 surrounds the sound-transmitting area 13, and the fixed connection area 11 surrounds the buffer area 12, wherein the fixed connection area 11 is located at the edge of the mesh membrane 1, and a through hole 121 penetrating the mesh membrane 1 is provided on the buffer area 12; the carrier 2 has a through opening 21, wherein the carrier 2 is connected to one side of the fixed connection area 11, and the opening 21 corresponds to the positions of the buffer area 12 and the sound-transmitting area 13.

[0040] In the dustproof structure for MEMS devices provided in the embodiment of the present invention, a buffer zone 12 is provided between the fixed connection area 11 and the sound-transmitting area 13 of the mesh membrane 1, and a through hole 121 penetrating the mesh membrane 1 is provided on the buffer zone 12; when connected to the carrier 2, the fixed connection area 11 of the mesh membrane 1 is directly connected to the carrier 2, and the opening 21 of the carrier 2 corresponds to the buffer zone 12 and the sound-transmitting area 13 of the mesh membrane 1. In this way, since the sound-transmitting area 13 and the fixed connection area 11 on the mesh membrane 1 are separated by the buffer zone 12, when the fixed connection area 11 is connected to the carrier 2, even if there is a stress difference and a different deformation amount at the connection position between the fixed connection area 11 and the carrier 2 due to differences in the material and thermal expansion coefficient, the influence of these differences on the fixed connection area 11 will be greatly reduced after being transmitted to the sound-transmitting area 13 after being relieved by the buffer zone 12. Specifically, the stress difference caused by the difference in material and the like is released through the through hole 121 opened on the buffer zone 12, thereby significantly reducing the impact on the sound-transmitting area 13; the deformation caused by the difference in thermal expansion coefficient is relieved by the through hole 121 opened on the buffer zone 12 and will not have a significant impact on the sound-transmitting area 13. Therefore, this ensures that the sound-transmitting area 13 can basically maintain a flat state, avoiding the phenomenon of wrinkles on the sound-transmitting area 13. After the dustproof structure provided by the embodiment of the present invention is applied to the MEMS microphone packaging structure, since the sound-transmitting area 13 on the grid membrane 1 is basically in a flat state, this is conducive to the smooth flow of air here and will not have an adverse effect on the movement of the airflow.

[0041] refer to Figure 1 , Figure 2 As shown, in the dustproof structure for MEMS devices provided in the embodiment of the present invention, the fixed connection area 11 of the grid membrane 1 is used to connect with the carrier 2. The middle part of the carrier 2 has a through opening 21, and the edge part 22 of the carrier 2 surrounds the opening 21. The fixed connection area 11 of the grid membrane 1 is specifically connected to the edge part 22 of the carrier 2, so that the grid membrane 1 can be stably covered on the carrier 2. The fixed connection area 11 of the grid membrane 1 is used to connect with the carrier 2, for example, by adhesive bonding, by hot pressing bonding, and of course, the two can also be connected together by fasteners or welding, etc. Those skilled in the art can flexibly choose according to specific needs, and the present invention does not limit this. The buffer zone 12 and the sound-permeable area 13 of the grid membrane 1 correspond to the opening 21 of the carrier 2 and are suspended.

[0042] In one embodiment, the sound-permeable area 13 is made of an isolation net, and the isolation net is configured to allow sound to pass through. The isolation net can, for example, be a metal screen with a mesh aperture of less than about 10 μm, so that the airflow can pass smoothly, and at the same time, it can effectively block the entry of dust, impurities and other particles from the outside. Moreover, the metal screen has the characteristics of good durability, does not need to be frequently replaced, and has a long service life. Of course, the isolation net can also be made of mesh cloth with other aperture sizes and other materials, for example, organic material non-woven fabrics can be used. Organic material non-woven fabrics have the characteristics of moisture-proof, breathable, flexible, light, non-combustible, easy to decompose, non-toxic and non-irritating, low price, recyclable and so on. In addition, the shape of the mesh on the isolation net can be, for example, circular, square, triangular and other shapes. Those skilled in the art can flexibly adjust according to specific needs, and the present invention is not limited to this.

[0043] It is understandable that on the mesh membrane 1, the shape of the sound-transmitting area 13 itself can be, for example, circular, square, elliptical, etc. Of course, the sound-transmitting area 13 can also be other irregular shapes. Those skilled in the art can flexibly adjust according to actual needs, and the present invention does not limit this.

[0044] In one embodiment, the buffer zone 12 is provided with a plurality of through holes 121, and the plurality of through holes 121 are evenly distributed along the area surrounding the sound-transmitting area 13. Evenly providing a plurality of through holes 121 distributed in the area surrounding the sound-transmitting area 13 on the buffer zone 12 can more effectively release stress and alleviate deformation, and more reliably ensure that the sound-transmitting area 13 of the mesh membrane 1 can basically maintain a flat state, and avoid the phenomenon of wrinkles on the sound-transmitting area 13.

[0045] In one embodiment, the through hole 121 is a circular hole. The circular through hole 121 has the advantages of simple opening process and convenient molding.

[0046] refer to Figure 2 As shown, in one embodiment, the through hole 121 is an elliptical hole, and the long axes of the plurality of elliptical holes are distributed around the sound-transmitting area 13. Designing the through hole 121 as an elliptical through hole 121 with the long axis distributed along the direction surrounding the sound-transmitting area 13 can more effectively utilize the area of ​​the buffer zone 12 to distribute the through hole 121, thereby making the buffer zone 12 more effective in releasing stress and relieving deformation. Of course, other shapes of through holes 121 can also be designed according to actual needs, refer to Figure 1 As shown, for example, in an embodiment where the sound-transmitting area 13 is circular, the through holes 121 are designed to have their major axes distributed along the radial direction of the sound-transmitting area 13. Figure 3 As shown, the through hole 121 is arc-shaped; for example, referring to Figure 4 As shown, the through hole 121 is crescent-shaped.

[0047] In one embodiment, the width of the buffer zone 12 is smaller than the width of the fixed connection zone 11. Setting the width of the fixed connection zone 11 to be larger can ensure the stability of the connection between the mesh membrane 1 and the carrier 2. In addition, the thickness of the buffer zone 12 can be set to be smaller than the thickness of the fixed connection zone 11. As a stress release and deformation buffering area, the thickness of the buffer zone 12 does not need to be set very thick. In addition, since the buffer zone 12 and the sound-transmitting zone 13 correspond to the opening 21 of the carrier 2 and are suspended, setting the buffer zone 12 and the sound-transmitting zone 13 to be thinner is beneficial to the stability of the installation of the entire mesh membrane 1.

[0048] In one embodiment, the buffer zone 12 is made of the same material as the fixed connection zone 11. The buffer zone 12 and the fixed connection zone 11 may also be made of, for example, a metal mesh or an organic non-woven fabric with a metal mesh as a base, or other materials that are convenient for connection with the carrier 2, and the present invention is not limited thereto.

[0049] In one embodiment, the average thickness of the mesh film 1 is in the range of 0.3 micrometers to 1.2 micrometers. The mesh film 1 within this thickness range can form a stable connection with the carrier 2 and can effectively block the entry of dust, impurities and other particles from the outside.

[0050] An embodiment of the present invention also provides a MEMS microphone packaging structure, which includes a shell 3 with a accommodating cavity, the shell 3 is provided with a sound hole 4, and the sound hole 4 connects the inside and outside of the shell 3; it also includes a microphone device and the dustproof structure as described above, the microphone device is fixedly arranged in the shell 3; the carrier 2 is fixedly connected to the shell 3; the mesh membrane 1 closes the sound hole 4; and / or the mesh membrane 1 is spaced between the sound hole 4 and the microphone device.

[0051] The MEMS microphone packaging structure can be applied to various types of electronic products such as mobile phones, laptops, iPads, VR devices, and smart wearable devices, and its application is relatively wide. The MEMS microphone packaging structure provided by the embodiment of the present invention can effectively prevent the internal microphone device and other components from being damaged by external dust, impurities and other particles and foreign matter, and can extend the service life of the microphone, and can also enable the microphone to maintain excellent acoustic performance.

[0052] refer to Figure 5-Figure 9As shown, the microphone packaging structure of the present invention has a shell 3 structured as follows: it includes a substrate 32 and a packaging cover 31, and the substrate 32 and the packaging cover 31 together enclose the accommodating cavity. The dustproof structure is accommodated in the accommodating cavity of the shell 3. Specifically, the sound hole 4 is opened on the substrate 32, and the microphone device includes a MEMS chip 5 and a signal amplifier 6 connected to each other. Among them, the MEMS chip 5 includes a substrate and a sensing film, and the substrate is a hollow structure. The sensing film is, for example, a piezoelectric element, a capacitor element, a piezoresistive element, etc. The sensing film is arranged at one end of the substrate and covers the hollow structure of the substrate, and the hollow structure forms a back cavity, which is connected to the sound hole 4, and the MEMS chip 5 is mounted on the substrate 32.

[0053] In an optional example of the present invention, Figure 5 As shown, the dustproof structure is located in the housing cavity of the housing 3 and covers the acoustic hole 4. Specifically, the carrier 2 is connected to the substrate 32 and is arranged around the acoustic hole 4. The mesh membrane 1 is arranged opposite to the acoustic hole 4 to prevent external dust, impurities and other particles and foreign matter from entering the housing cavity of the housing 3 through the acoustic hole 4. Figure 5 In the illustrated embodiment, the dustproof structure is entirely located in the back cavity of the MEMS chip 5 , and the external airflow first passes through the filtering effect of the mesh membrane 1 of the dustproof structure before entering the back cavity of the chip 5 .

[0054] In an optional example of the present invention, Figure 6 As shown, the dustproof structure is located in the housing cavity of the housing 3 and covers the acoustic hole 4. Specifically, the carrier 2 is connected to the substrate 32 and is arranged around the acoustic hole 4. The mesh membrane 1 is arranged opposite to the acoustic hole 4 to prevent external dust, impurities and other particles and foreign matter from entering the housing cavity of the housing 3 through the acoustic hole 4. Figure 6 In the embodiment shown, the MEMS chip 5 is connected to the side of the grid membrane 1 of the dustproof structure away from the carrier 2, specifically connected to the side of the fixed connection area 11 away from the carrier 2. The external airflow first passes through the filtering effect of the grid membrane 1 of the dustproof structure before entering the back cavity of the chip 5.

[0055] Of course, the dustproof structure of the present invention may also have other configuration modes:

[0056] For example, Figure 7 As shown, the sound hole 4 is opened on the packaging cover 31, and the dustproof structure cover is arranged at a position on the packaging cover 31 corresponding to the sound hole 4 and is located outside the housing 3. Figure 8As shown, the sound hole 4 is opened on the packaging cover 31, and the dustproof structure cover is arranged at a position on the packaging cover 31 corresponding to the sound hole 4 and is located in the accommodating cavity of the housing 3. The position of the dustproof structure corresponds to the sound hole 4, which can prevent external particles and foreign objects from being introduced into the microphone packaging structure through the sound hole 4. For another example, Fig. 9 As shown, the sound hole 4 is located on the packaging cover 31, and the dustproof structure is fixedly connected to the substrate 32 at a position corresponding to the sound hole 4. At this time, the dustproof structure can effectively protect the microphone device in the microphone packaging structure.

[0057] 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 dustproof structure for a MEMS device, characterized in that: include: Grid The mesh membrane has a fixed connection area, a buffer area and a sound-transmitting area, the buffer area surrounds the sound-transmitting area, the fixed connection area surrounds the buffer area, the fixed connection area is located at the edge of the mesh membrane, and the buffer area is provided with a through hole penetrating the mesh membrane; A carrier, wherein the carrier has a through opening, the carrier is connected to one side of the fixed connection area, and the opening corresponds to the position of the buffer area and the sound-transmitting area; The sound-transmitting area is made of an isolation net, and the isolation net is configured to allow sound to pass through.

2. The dustproof structure according to claim 1, characterized in that: The isolation net is an organic non-woven fabric or a metal screen.

3. The dustproof structure according to claim 1, characterized in that: The buffer zone is provided with a plurality of through holes, and the plurality of through holes are evenly distributed along a region surrounding the sound-transmitting zone.

4. The dustproof structure according to claim 1, characterized in that: The through hole is a round hole.

5. The dustproof structure according to claim 1, characterized in that: The through hole is an elliptical hole.

6. The dustproof structure according to claim 1, characterized in that: The width of the buffer area is smaller than the width of the fixed connection area.

7. The dustproof structure according to claim 1, characterized in that: The buffer area is made of the same material as the fixed connection area.

8. The dustproof structure according to claim 1, characterized in that: The average thickness of the mesh film is in the range of 0.3 micrometers to 1.2 micrometers.

9. A MEMS microphone packaging structure, characterized in that: include: A shell having a receiving cavity, wherein a sound hole is provided on the shell, and the sound hole connects the inside and the outside of the shell; A microphone device, wherein the microphone device is fixedly disposed in the housing; The dustproof structure according to any one of claims 1 to 8, wherein the carrier is fixedly connected to the housing; The mesh membrane closes the sound hole; and / or the mesh membrane is spaced between the sound hole and the microphone device.

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