MEMS product packaging structure

Abstract

The utility model discloses an MEMS product packaging structure, comprising a circuit board, a housing arranged above the circuit board, a cavity arranged in the housing, an ASIC chip arranged in the cavity, a gold thread connected to the right end of the ASIC chip, an MEMS chip connected to the other end of the gold thread, and a noise reduction mechanism arranged above the housing. By adopting a new shell design, the problem that a high-sensitivity and high-signal-to-noise-ratio product is difficult to manufacture is effectively solved, after external sound enters a sound hole through a noise reduction mechanism, the sound is buffered and dissipated in a buffer cavity, and a partition plate effectively keeps the sound from directly impacting the interior of a cavity; in addition, the cover plate also has dustproof and waterproof effects to prevent airflow from directly impacting the MEMS chip and the ASIC chip, so that a protection effect is achieved, the damage rate of the MEMS chip and the ASIC chip is effectively reduced, the service life is prolonged, and the design can be applied to both a front sound inlet product and a back sound inlet product.

Description

Technical Field

[0001] The utility model relates to the technical field of MEMS products, in particular to a MEMS product packaging structure. Background Art

[0002] Micro-electromechanical systems, or MEMS for short, are an emerging scientific field that integrates micro-machines, micro-sensors, micro-actuators, signal processing, and intelligent control. It combines conventional integrated circuit technology with the unique special technology of micro-machining, and involves a variety of engineering technologies and disciplines such as microelectronics, mechanical design, automatic control, materials science, optics, mechanics, biology, acoustics, and electromagnetism. It is a multidisciplinary integrated technology. The main contents of MEMS research include micro-sensors, micro-actuators, and various micro-systems. It has now become a hot spot for research in countries around the world with a large amount of investment.

[0003] With the development of technologies such as artificial intelligence and AI, higher requirements are placed on MEMS microphones. Smaller-sized high-signal-to-noise ratio products have gained greater market favor due to their advantages such as high sensitivity and high signal-to-noise ratio.

[0004] Existing MEMS such as Figure 1 As shown, there is a circuit board 1, a shell 2 is installed above the circuit board 1, a cavity 3 is arranged inside the shell 2, an ASIC chip 4 and a MEMS chip 7 are arranged in the cavity 3, the ASIC chip 4 is connected to a gold wire, and the other end of the gold wire is connected to the MEMS chip 7. The shell 2 of the product has an R angle 9, which will result in a smaller cavity of the shell 2. The smaller the cavity, the lower the sensitivity and signal-to-noise ratio, the more blurred the sound that can be picked up, the lower the sound quality of the sound playback, the smaller the compliance of the diaphragm, and the limited vibration of the diaphragm, resulting in a series of problems such as low sensitivity and low signal-to-noise ratio.

[0005] Therefore, a new structural design and packaging process are proposed to solve this problem, which greatly improves the MEMS product packaging structure with indicators such as product sensitivity, signal-to-noise ratio, and high-frequency curve. Utility Model Content

[0006] The purpose of the utility model is to provide a MEMS product packaging structure to solve the problems raised in the above background technology.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A MEMS product packaging structure includes a circuit board, a shell installed above the circuit board, a cavity inside the shell, an ASIC chip installed in the cavity, a gold wire connected to the right end of the ASIC chip, the other end of the gold wire connected to the MEMS chip, and the shell is flush with the circuit board after removing the R corner.

[0009] Furthermore, a noise reduction mechanism is installed above the shell, and the noise reduction mechanism includes a sound hole installed above the shell, a buffer cavity is installed below the sound hole, and a partition is installed below the buffer cavity.

[0010] Furthermore, the ASIC chip is bonded on the circuit board by a sealant.

[0011] Furthermore, the housing and the circuit board are tightly bonded by a sealant.

[0012] Furthermore, the MEMS chip and the ASIC chip are electrically connected to the circuit board via gold wires respectively.

[0013] Furthermore, three sound holes are provided and installed above the shell.

[0014] Furthermore, the material used for the shell is noise reduction material.

[0015] Compared with the prior art, the technical effects and advantages of the utility model are: a MEMS product package provided by the utility model adopts a new shell design: removing the R corner of the shell effectively solves the problem that high-sensitivity and high signal-to-noise ratio products are difficult to make, the implementation method is simple, the process is mature, and the yield is high. When external sound enters the sound hole through the noise reduction mechanism, the sound will be buffered and dissipated in the buffer cavity, and the partition effectively keeps the sound from directly impacting the cavity; the cover plate also has the effect of dustproof and waterproof to prevent airflow from directly impacting the MEMS chip and ASIC chip, which plays a protective role, effectively reduces the damage rate of MEMS chip and ASIC chip, and extends the service life. This design can be applied to front sound products as well as rear sound products. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram of the packaging structure of a prior art MEMS product;

[0017] Figure 2 This is a cross-sectional view of the overall structure of the utility model;

[0018] Figure 3 This is the front view of the utility model;

[0019] Figure 4 It is a top view of the utility model;

[0020] Figure 5 This is a bottom view of the utility model;

[0021] In the figure: 1. circuit board; 2. shell; 3. cavity; 4. ASIC chip; 5. sealant; 6. gold wire; 7. MEMS chip; 81. sound hole; 82. buffer cavity; 83. partition; 9. R angle. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] In the description of the present invention, it should be noted that the terms "upper end", "lower end", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "sleeved", "sleeved", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0025] Example 1

[0026] See also Figure 1 to Figure 2 , the utility model provides a technical solution:

[0027] A MEMS product packaging structure includes a circuit board 1, a shell 2 is installed above the circuit board 1, a cavity 3 is provided inside the shell 2, an ASIC chip 4 is installed in the cavity 3, a gold wire 6 is connected to the right end of the ASIC chip 4, and the other end of the gold wire 6 is connected to the MEMS chip 7. The shell 2 removes the R angle 9 (thus becoming a right angle a) and is flush with the circuit board 1.

[0028] In the specific implementation process, Figure 1 As shown, the ASIC chip 4 is bonded on the circuit board 1 by a sealant 5 .

[0029] It should be noted that the ASIC chip 4 is bonded to the top of the circuit board 1 by the sealant 5 , and the sealant 5 will firmly bond the ASIC chip 4 together.

[0030] In the specific implementation process, Figure 1 As shown, the housing 2 and the circuit board 1 are tightly bonded by a sealant 5 .

[0031] It should be noted that the housing 2 and the circuit board 1 are tightly bonded by the sealant 5. The sealant 5 firmly bonds the contact area between the housing 2 and the circuit board 1 so that no gap will appear, and the sound insulation effect is better.

[0032] In the specific implementation process, Figure 1 As shown, the MEMS chip 7 and the ASIC chip 4 are electrically connected to the circuit board 1 via gold wires 6 respectively.

[0033] It should be noted that the MEMS chip 7 and the ASIC chip 4 are electrically connected to the circuit board 1 through gold wires 6 respectively, and the gold wires 6 enable them to better transmit and convert signals.

[0034] Example 2

[0035] It is basically the same as Example 1, with the following slight differences:

[0036] In the specific implementation process, Figure 3-5 As shown, a noise reduction mechanism 8 is installed above the shell 2 , and the noise reduction mechanism 8 includes a sound hole 81 installed above the shell 2 , a buffer cavity 82 is installed below the sound hole 81 , and a partition plate 83 is installed below the buffer cavity 82 .

[0037] It should be noted that a sound hole 81 is installed above the shell 2, and a buffer cavity 82 is installed below the sound hole 81, and a partition 83 is installed below the buffer cavity 82. When external sound enters the sound hole 81, the sound will be buffered and dissipated in the buffer cavity 82, and the partition 83 effectively prevents the sound from directly impacting the cavity 3; the cover plate 83 also has the effect of dustproof and waterproof to prevent the airflow from directly impacting the MEMS chip 7 and the ASIC chip 4, plays a protective role, effectively reduces the damage rate of the MEMS chip 7 and the ASIC chip 4, and prolongs the service life.

[0038] In the specific implementation process, Figure 1 As shown, three sound holes 81 are provided and installed above the housing 2 .

[0039] like Figure 1 As shown, the R angle of the housing 2 can also be removed while removing the corner b of the housing.

[0040] It should be noted that three sound holes 81 are provided and installed above the housing 2 . Providing three sound holes 81 can effectively reduce the signal-to-noise ratio.

[0041] In the specific implementation process, Figure 1The material used for the shell 2 shown can also be a noise reduction material.

[0042] The working principle of this embodiment is as follows: during specific use, when external sound enters the sound hole 81, the sound will be buffered and dissipated in the buffer cavity 82, and the partition 83 effectively keeps the sound from directly impacting the cavity 3; the cover plate 83 also has the effect of dustproof and waterproof to prevent the airflow from directly impacting the MEMS chip 7 and the ASIC chip 4, and plays a protective role, effectively reducing the damage rate of the MEMS chip 7 and the ASIC chip 4, and extending the service life. The sealant 5 will firmly bond the ASIC chip 4 together, and the sealant 5 will firmly bond the contact area between the shell 2 and the circuit board 1 so that no gap will appear, and the sound insulation effect is better. The MEMS chip 7 and the ASIC chip 4 are electrically connected to the circuit board 1 respectively through the gold wire 6, and the gold wire 6 enables them to better transmit and convert signals. The sound hole 81 is provided with three installed above the shell 2. The provision of three sound holes 81 can effectively reduce the signal-to-noise ratio.

[0043] Under the same conditions, the larger the cavity 3 is, the higher the sensitivity is and the higher the signal-to-noise ratio is. On the contrary, the smaller the cavity 3 is, the lower the sensitivity is and the lower the signal-to-noise ratio is.

[0044] The signal-to-noise ratio (SNR) refers to the ratio of signal to noise. For example, the noise of a MEMS microphone depends on the background noise of the chip. If the sensitivity is increased while the chip remains unchanged, the signal-to-noise ratio will be increased accordingly. The higher the signal-to-noise ratio, the better the effect of the audio product, the more detailed the sound that can be picked up, and the higher the sound quality of the sound playback. Therefore, this design improves the sound reception effect.

[0045] The frequency response curve is a graph represented by a rectangular coordinate system with frequency (unit: "Hertz / Hz") as the independent variable and sensitivity (unit: "decibel / dB") as the dependent variable.

[0046] The utility model adopts a new shell design, which effectively solves the problem that high-sensitivity and high-signal-to-noise ratio products are difficult to make, and does not change other components. The implementation method is simple, the process is mature, and the yield rate is high. This design can be applied to front sound products as well as rear sound products. Specifically:

[0047] While keeping the internal parts and structure unchanged, the utility model makes the volume of the cavity 3 larger through the new shell 2 structural design method, solves the problem that high-sensitivity and high-signal-to-noise ratio products are difficult to produce and the signal-to-noise ratio (SNR) is low, makes the design more reasonable, and the space for the selection of chips (such as the ASIC chip 4 and the MEMS chip 7 in the utility model) is wider, providing a broad design platform for the subsequent derivative related products. In addition, the structure is simple and easy to make, the cost is low, the process flow is mature, and the yield rate is high. At the same time, the appearance of the newly designed product is a completely square design, the contact area of ​​the top surface is larger, and it is more conducive to customer use. Thereby solving the problem that the prior art design generally has an R angle 9 (or rounded corners) resulting in a small area of ​​the top surface of the shell 2, which is not conducive to customer use.

[0048] Material selection: the shell 2 can be made of metal, plastic, ceramic, etc. This packaging structure can also be used to package the MEMS electronic cigarette microphone.

[0049] The remaining parts not described in this utility model are existing or known technologies.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A MEMS product packaging structure, characterized in that: The invention comprises a circuit board (1), a housing (2) is installed above the circuit board (1), a cavity (3) is provided inside the housing (2), an ASIC chip (4) and a MEMS chip (7) are provided inside the cavity (3), the right end of the ASIC chip (4) is connected to a gold wire (6), the other end of the gold wire (6) is connected to the MEMS chip (7), and the side surface of the housing (2) after removing the R angle (9) is flush with the end of the circuit board (1).

2. A MEMS product packaging structure according to claim 1, characterized in that: A noise reduction mechanism (8) is installed above the shell (2), and the noise reduction mechanism (8) comprises a sound hole (81) installed above the shell (2), a buffer cavity (82) is installed below the sound hole (81), and a partition plate (83) is installed below the buffer cavity (82).

3. A MEMS product packaging structure according to claim 1, characterized in that: The ASIC chip (4) is bonded onto the circuit board (1) by a sealant (5).

4. A MEMS product packaging structure according to claim 1, characterized in that: The housing (2) and the circuit board (1) are tightly bonded together by means of a sealant (5).

5. A MEMS product packaging structure according to claim 1, characterized in that: The MEMS chip (7) and the ASIC chip (4) are packaged on a circuit board (1), and are electrically connected to the circuit board (1) via gold wires (6) respectively.

6. A MEMS product packaging structure according to claim 2, characterized in that: The sound holes (81) are provided with three and are installed above the housing (2).

7. A MEMS product packaging structure according to claim 1, characterized in that: The material of the shell (2) is metal, plastic or ceramic.

Images