Sensor packaging structure and fabrication method and electronic equipment

Abstract

This application provides a sensor packaging structure and an electronic device, wherein the sensor packaging structure includes: a substrate having a first acoustic hole extending through its thickness direction; a cover disposed on a first side of the substrate, the cover and the substrate cooperating to form a receiving cavity; a sensor assembly disposed in the receiving cavity; and a waterproof membrane disposed on the first side of the substrate, the waterproof membrane being located within the receiving cavity, the effective area of ​​the waterproof membrane corresponding to the opening of the first acoustic hole, the area of ​​the effective area being larger than the opening area of ​​the first acoustic hole; in the axial direction of the first acoustic hole, the distance between the first acoustic hole and the effective area is H1, and in the radial direction of the first acoustic hole, the distance between the inner wall surface of the first acoustic hole and the edge of the effective area is L1, the ratio of H1 to L1 being greater than 1:8.

Description

Technical Field

[0001] This application relates to the field of packaging structure technology, and more specifically, to a sensor packaging structure, its fabrication method, and an electronic device. Background Technology

[0002] In related technologies, MEMS microphone sensor packaging structures typically incorporate a large waterproof membrane inside to achieve waterproofing. This membrane protects sensitive electronic components from damage by preventing external moisture from entering the sensor through the acoustic aperture. However, the aperture size in existing microphone sensor packaging structures is relatively small compared to the effective area of ​​the waterproof membrane, resulting in underutilization of the membrane's effective area and consequently, a low signal-to-noise ratio, which limits the sensor's acoustic performance. Summary of the Invention

[0003] This application provides a new technical solution for sensor packaging structure, which can at least solve the problem of low acoustic performance of existing packaging structures.

[0004] This application also provides a new technical solution for an electronic device.

[0005] According to a first aspect of this application, a sensor packaging structure is provided, comprising: a substrate having a first acoustic hole extending through its thickness direction; a housing disposed on a first side of the substrate, the housing and the substrate cooperating to form a receiving cavity; a sensor assembly disposed in the receiving cavity; and a waterproof membrane disposed on the first side of the substrate, the waterproof membrane being located within the receiving cavity, the effective area of ​​the waterproof membrane corresponding to the opening of the first acoustic hole, the area of ​​the effective area being larger than the opening area of ​​the first acoustic hole; in the axial direction of the first acoustic hole, the distance between the first acoustic hole and the effective area is H1, and in the radial direction of the first acoustic hole, the distance between the inner wall surface of the first acoustic hole and the edge of the effective area is L1, the ratio of H1 to L1 being greater than 1:8.

[0006] Optionally, the minimum radial dimension of the first acoustic hole is d1, where 0.25mm≤d1≤1mm.

[0007] Optionally, the first acoustic hole is a circular hole or a rectangular hole.

[0008] Optionally, the first acoustic hole is a circular hole with a diameter of 8 mm.

[0009] Optionally, the first side of the substrate is provided with a mounting groove, the first acoustic hole is provided at the bottom of the mounting groove, the waterproof membrane is provided in the mounting groove, and the sensor packaging structure further includes: a support sheet, the support sheet is provided at the opening end of the mounting groove, the support sheet is connected to the substrate, the support sheet is provided with a second acoustic hole penetrating along its thickness direction, the second acoustic hole is connected to the mounting groove, the opening area of ​​the second acoustic hole is smaller than the area of ​​the effective area, the sensor assembly is provided on the side of the support sheet away from the waterproof membrane, and the position of the sensor assembly corresponds to the position of the second acoustic hole; in the axial direction of the first acoustic hole, the distance between the second acoustic hole and the effective area is H2, and in the radial direction of the first acoustic hole, the distance between the inner wall surface of the second acoustic hole and the edge of the effective area is L2, and the ratio of H2 to L2 is greater than 1:8.

[0010] Optionally, H1 ≤ 50 μm, the ratio of H1 to L1 is 1:1, and / or H2 ≤ 50 μm, the ratio of H2 to L2 is 1:1.

[0011] Optionally, the first acoustic hole is aligned with the center of the effective area, and / or the first acoustic hole is aligned with the center of the second acoustic hole.

[0012] Optionally, the first acoustic hole, the effective area, and the second acoustic hole have the same shape.

[0013] Optionally, the first acoustic hole is a rectangular hole, the width of the rectangular hole is the minimum radial dimension of the first acoustic hole, the length of the rectangular hole is d2, and the ratio of d2 to d1 is 2 to 1:1.

[0014] According to a second aspect of this application, an electronic device is provided, including the sensor packaging structure described in any of the preceding claims.

[0015] According to the sensor packaging structure of this application, by controlling the ratio of H1 to L1 to be greater than 1:8, the effective area of ​​the waterproof membrane can be fully utilized, thereby effectively improving the signal-to-noise ratio of the sensor packaging structure and enhancing the acoustic performance of the sensor packaging structure.

[0016] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0018] Figure 1 This is a schematic diagram of a sensor packaging structure according to an embodiment of the present application.

[0019] Figure Labels

[0020] 100. Sensor packaging structure;

[0021] 10. Substrate; 11. Mounting slot; 12. First acoustic hole;

[0022] 20. Waterproof membrane; 21. Support structure; 22. Membrane body;

[0023] 30. Support plate; 31. Second acoustic hole;

[0024] 40. Sensor components; 41. MEMS chips; 42. ASIC chips;

[0025] 50. Cover. Detailed Implementation

[0026] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0027] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0028] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0029] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0031] The sensor packaging structure 100 according to an embodiment of this application will now be described in detail with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the sensor packaging structure 100 according to an embodiment of this application includes: a substrate 10, a housing 50, a sensor assembly 40, and a waterproof membrane 20.

[0033] Specifically, the substrate 10 has a first acoustic hole 12 extending through its thickness direction, the cover 50 is disposed on the first side of the substrate 10, and the cover 50 and the substrate 10 cooperate to form a receiving cavity, the sensor assembly 40 is disposed in the receiving cavity, the waterproof membrane 20 is disposed on the first side of the substrate 10, the waterproof membrane 20 is located in the receiving cavity, the effective area of ​​the waterproof membrane 20 corresponds to the opening of the first acoustic hole 12, and the area of ​​the effective area is larger than the opening area of ​​the first acoustic hole 12; in the axial direction of the first acoustic hole 12, the distance between the first acoustic hole 12 and the effective area is H1, and in the radial direction of the first acoustic hole 12, the distance between the inner wall surface of the first acoustic hole 12 and the edge of the effective area is L1, and the ratio of H1 to L1 is greater than 1:8.

[0034] In other words, the sensor packaging structure 100 according to the embodiments of this application mainly consists of a substrate 10, a cover 50, a sensor assembly 40, and a waterproof membrane 20. The substrate 10 can be a PCB board, and one side of the substrate 10 in its thickness direction is a first side. The cover 50 is fixedly connected to the first side of the substrate 10, and a receiving cavity is formed by the inner wall surface of the cover 50 cooperating with the first side of the substrate 10. The substrate 10 has a first acoustic hole 12 that penetrates along its thickness direction at a position corresponding to the receiving cavity. The sensor assembly 40 and the waterproof membrane 20 are both disposed in the receiving cavity.

[0035] The waterproof membrane 20 includes a support 21 and a membrane 22. The support 21 has a through-channel extending along the thickness direction of the substrate 10. The membrane 22 is located at the first end of the through-channel and is fixedly connected to the support 21. The area of ​​the membrane 22 corresponding to the through-channel constitutes the effective area of ​​the waterproof membrane 20, and the area of ​​this effective area is larger than the cross-sectional area of ​​the first acoustic hole 12. The second end of the through-channel corresponds to the position of the first acoustic hole 12, and the support 21 is fixedly connected to the substrate 10, so that the waterproof membrane 20 can effectively block the first acoustic hole 12, thereby preventing external moisture from entering the cavity.

[0036] In the axial direction of the first acoustic aperture 12, the distance from the first acoustic aperture 12 to the effective area is H1, and in the radial direction of the first acoustic aperture 12, the distance from the inner wall surface of the first acoustic aperture 12 to the edge of the effective area is L1. With a fixed size for the waterproof membrane 20, if the ratio of H1 to L1 is too small, it means that the radial dimension of the first acoustic aperture 12 is too small relative to the radial dimension of the effective area of ​​the waterproof membrane 20, making it impossible to fully utilize the area of ​​the effective area of ​​the waterproof membrane 20, resulting in a low signal-to-noise ratio for the sensor packaging structure 100. To avoid this situation, in this embodiment, the ratio of H1 to L1 is greater than 1:8. For example, the ratio of H1 to L1 can be 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, and 1:1, etc. Within this range, the effective area of ​​the waterproof membrane 20 can be effectively utilized, which can effectively improve the signal-to-noise ratio of the sensor packaging structure 100, thereby effectively improving the acoustic performance of the sensor.

[0037] Therefore, according to the sensor packaging structure 100 provided in this embodiment, by controlling the ratio of H1 to L1 to be greater than 1:8, the effective area of ​​the waterproof membrane 20 can be fully utilized, thereby effectively improving the signal-to-noise ratio of the sensor packaging structure 100 and enhancing the acoustic performance of the sensor packaging structure 100.

[0038] In some embodiments of this application, the minimum radial dimension of the first acoustic hole 12 is d1, where 0.25mm≤d1≤1mm.

[0039] Specifically, the first acoustic hole 12 can be a circular hole or a rectangular hole, etc., and the rectangular hole can be a chamfered rectangular hole. When the first acoustic hole 12 is a circular hole, the diameter of the circular hole is the minimum radial dimension of the first acoustic hole 12; when the first acoustic hole 12 is a rectangular hole, the width of the rectangular hole is the minimum radial dimension of the first acoustic hole 12.

[0040] The larger the minimum radial dimension of the first acoustic aperture 12, the higher the signal-to-noise ratio of the sensor packaging structure 100. However, if the minimum radial dimension of the first acoustic aperture 12 is too large, it will result in too much exposed area of ​​the waterproof membrane 20, making it easier for sharp objects to puncture the waterproof membrane 20. In this embodiment, the minimum radial dimension d1 of the first acoustic aperture 12 is set between 0.25mm and 1mm. For example, d1 can be 0.25mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1mm, etc. Within this range, the sensor packaging structure 100 can be ensured to have a good signal-to-noise ratio while maintaining its waterproof performance.

[0041] In some optional examples of this application, the first acoustic hole 12 is a circular hole with a diameter of 8 mm.

[0042] In other words, the first acoustic hole 12 is a circular hole, and the diameter of the circular hole is the minimum radial dimension of the first acoustic hole 12. When the diameter of the circular hole is less than 0.8 mm, the signal-to-noise ratio (SNR) of the sensor packaging structure 100 is relatively low. For example, when the diameter of the circular hole is 0.6 mm, the SNR of the sensor packaging structure 100 is 0.2 dB lower than when the diameter is 0.8 mm. However, when the diameter of the circular hole is greater than 0.8 mm, the SNR of the sensor packaging structure 100 does not improve; instead, it increases the exposed area of ​​the waterproof membrane 20, thereby increasing the risk of the waterproof membrane 20 being punctured by sharp external objects. In this example, the diameter of the circular hole is set to 0.8 mm. This size maximizes the SNR of the sensor packaging structure 100 while minimizing the exposed area of ​​the waterproof membrane 20, ensuring the waterproof performance of the sensor packaging structure 100.

[0043] Table 1:

[0044] First acoustic hole diameter Φ0.6mm Φ0.8mm L1 B B-100um H1 A (≥50um) A (≥50um) H1 / L1 0.223 0.403 Product signal-to-noise ratio C C+0.2dB

[0045] In some embodiments of this application, a mounting groove 11 is provided on the first side of the substrate 10, a first acoustic hole 12 is provided at the bottom of the mounting groove 11, a waterproof membrane 20 is provided in the mounting groove 11, and the sensor packaging structure 100 further includes: a support sheet 30, which is provided at the opening end of the mounting groove 11 and connected to the substrate 10. The support sheet 30 is provided with a second acoustic hole 31 that extends through its thickness direction and communicates with the mounting groove 11. The opening area of ​​the second acoustic hole 31 is smaller than the area of ​​the effective area. A sensor assembly 40 is provided on the side of the support sheet 30 away from the waterproof membrane 20, and the positions of the sensor assembly 40 and the second acoustic hole 31 correspond. In the axial direction of the first acoustic hole 12, the distance between the second acoustic hole 31 and the effective area is H2. In the radial direction of the first acoustic hole 12, the distance between the inner wall surface of the second acoustic hole 31 and the edge of the effective area is L2. The ratio of H2 to L2 is greater than 1:8.

[0046] In other words, according to the embodiment of this application, the first side of the substrate 10 is provided with a mounting groove 11, which is located within the accommodating cavity. The substrate 10 has a first acoustic hole 12 extending through its thickness direction at the bottom of the mounting groove 11. A waterproof membrane 20 is disposed within the mounting groove 11, and the support body 21 of the waterproof membrane 20 is fixedly connected to the bottom of the mounting groove 11. A support piece 30 that blocks the opening of the mounting groove 11 is fixedly connected to the first side of the substrate 10. The support piece 30 has a second acoustic hole 31 extending through its thickness direction, and the second acoustic hole 31 corresponds to the position of the mounting groove 11. The second acoustic hole 31 is smaller than the opening of the mounting groove 11, thereby providing the required mounting position for the sensor assembly 40.

[0047] The sensor assembly 40 mainly includes a MEMS chip 41 and an ASIC chip 42. The MEMS chip 41 has a vibration cavity that extends through the thickness direction of the substrate 10. The MEMS chip 41 is fixedly connected to the side of the support plate 30 away from the mounting groove 11, and the vibration cavity of the MEMS chip 41 corresponds to the position of the second sound hole 31. The ASIC chip 42 is fixedly connected to the first side of the substrate 10.

[0048] Specifically, in the axial direction of the first acoustic hole 12, the distance from the second acoustic hole 31 to the effective area is H2, and in the radial direction of the first acoustic hole 12, the distance from the inner wall surface of the first acoustic hole 12 to the edge of the effective area is L2. With a fixed size for the waterproof membrane 20, if the ratio of H1 to L1 is too small, it means that the radial dimension of the second acoustic hole 31 is too small relative to the radial dimension of the effective area of ​​the waterproof membrane 20, making it impossible to fully utilize the area of ​​the effective area of ​​the waterproof membrane 20, resulting in a low signal-to-noise ratio for the sensor packaging structure 100. To avoid this situation, in this embodiment, the ratio of H2 to L2 is greater than 1:8. For example, the ratio of H2 to L2 can be 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, and 1:1, etc. Within this range, the effective area of ​​the waterproof membrane 20 can be effectively utilized, which can effectively improve the signal-to-noise ratio of the sensor packaging structure 100, thereby effectively improving the acoustic performance of the sensor packaging structure 100.

[0049] According to one embodiment of this application, H1 ≤ 50 μm, the ratio of H1 to L1 is 1:1, and / or, H2 ≤ 50 μm, the ratio of H2 to L2 is 1:1.

[0050] If H1 ≤ 50µm, a small slit will be formed between the waterproof membrane 20 and the substrate 10. This slit will generate a large acoustic impedance, and due to multiple reflections of sound waves within the slit, it will increase the absorption and loss of sound energy. When the ratio of H1 to L1 is less than 1:1, it indicates that the slit between the waterproof membrane 20 and the substrate 10 is relatively large, which will cause excessive sound energy to be absorbed, resulting in a low signal-to-noise ratio of the sensor packaging structure 100. Conversely, when the ratio of H1 to L1 is greater than 1:1, it indicates that the slit between the waterproof membrane 20 and the substrate 10 is relatively small, which is not conducive to absorbing noise generated at the edge of the waterproof membrane 20, and will also lead to a low signal-to-noise ratio of the sensor packaging structure 100. In this embodiment, the ratio of H1 to L1 is 1:1. At this ratio, the signal-to-noise ratio of the sensor packaging structure 100 can be maintained at a better level, which can effectively improve the acoustic performance of the sensor packaging structure 100.

[0051] Furthermore, if H2 ≤ 50µm, a small slit will be formed between the waterproof membrane 20 and the support sheet 30. This slit will generate a large acoustic impedance, and due to multiple reflections of sound waves within the slit, it will increase the absorption and loss of sound energy. When the ratio of H2 to L2 is less than 1:1, it indicates that the slit between the waterproof membrane 20 and the support sheet 30 is relatively large, which will cause excessive sound energy to be absorbed, resulting in a low signal-to-noise ratio of the sensor packaging structure 100. Conversely, when the ratio of H2 to L2 is greater than 1:1, it indicates that the slit between the waterproof membrane 20 and the support sheet 30 is relatively small, which is not conducive to absorbing noise generated at the edge of the waterproof membrane 20, and will also lead to a low signal-to-noise ratio of the sensor packaging structure 100. In this embodiment, the ratio of H2 to L2 is 1:1. At this ratio, the signal-to-noise ratio of the sensor packaging structure 100 can be maintained at a better level, which can effectively improve the acoustic performance of the sensor packaging structure 100.

[0052] In some embodiments of this application, the first acoustic hole 12 is aligned with the center of the effective area, and / or the first acoustic hole 12 is aligned with the center of the second acoustic hole 31.

[0053] Specifically, to reduce lateral acoustic impedance, the first acoustic aperture 12 can be aligned with the effective area of ​​the waterproof membrane 20, and the first acoustic aperture 12 can be aligned with the second acoustic aperture 31, thereby aligning the first acoustic aperture 12, the effective area of ​​the waterproof membrane 20, and the second acoustic aperture 31. This arrangement effectively transmits sound waves to the sensor assembly 40, significantly improving the signal-to-noise ratio of the sensor packaging structure 100, and thus enhancing the acoustic performance of the sensor packaging structure 100.

[0054] According to one embodiment of this application, the first sound hole 12 and the effective area have the same shape as the second sound hole 31.

[0055] In other words, the shapes of the first acoustic aperture 12, the effective area, and the second acoustic aperture 31 are consistent. Specifically, if the first acoustic aperture 12 is circular, then the effective area will also be designed as circular, and the second acoustic aperture 31 will also be circular. Similarly, if the first acoustic aperture 12 is rectangular, the effective area will be designed as a rectangle with the same aspect ratio as the first acoustic aperture 12, and the second acoustic aperture 31 will also be rectangular. This arrangement is beneficial for sound wave transmission and can effectively improve the acoustic performance of the sensor packaging structure 100.

[0056] According to one embodiment of this application, the first acoustic hole 12 is a rectangular hole, the width of the rectangular hole is the minimum radial dimension of the first acoustic hole 12, the length of the rectangular hole is d2, and the ratio of d2 to d1 is 2 to 1:1.

[0057] Specifically, the first acoustic aperture 12 is a rectangular aperture, for example, a chamfered rectangular aperture. The ratio of the width d1 to the length d2 of the rectangular aperture has a significant impact on the resonance peak and noise floor in the audio frequency band. Specifically, if the ratio of d2 to d1 is greater than 2:1, that is, the length is twice or more than the width, this will cause the sensor package structure 100 to easily exhibit resonance peaks and high noise floor in the audio frequency band. In this embodiment, the ratio of d2 to d1 is between 1:1 and 2:1. Using this ratio range can effectively reduce the generation of resonance peaks, thereby effectively ensuring the acoustic performance of the sensor package structure 100.

[0058] In summary, according to the sensor packaging structure 100 provided in this embodiment, by controlling the ratio of H1 to L1 to be greater than 1:8, the effective area of ​​the waterproof membrane 20 can be fully utilized, thereby effectively improving the signal-to-noise ratio of the sensor packaging structure 100 and enhancing the acoustic performance of the sensor packaging structure 100.

[0059] Embodiments of this application also provide an electronic device, including the electronic device of any of the above embodiments. Since the sensor packaging structure according to the embodiments of the application has the above-described technical effects, the electronic device according to the embodiments of this application also has corresponding technical effects, which will not be repeated in this embodiment.

[0060] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A sensor package structure, characterized by, The sensor package structure comprises: a substrate provided with a first sound hole penetrating through the thickness direction of the substrate; a cover provided on the first side of the substrate, the cover and the substrate cooperating to form a receiving cavity; a sensor assembly provided in the receiving cavity; a waterproof film provided on the first side of the substrate, the waterproof film being located in the receiving cavity, an effective area of the waterproof film corresponding to the opening of the first sound hole, the area of the effective area being greater than the opening area of the first sound hole; in the axial direction of the first sound hole, the distance between the first sound hole and the effective area is H1, in the radial direction of the first sound hole, the distance between the inner wall surface of the first sound hole and the edge of the effective area is L1, the ratio of H1 to L1 is greater than 1:8 and less than or equal to 1:1, the minimum radial dimension of the first sound hole is d1, 0.25mm≤d1≤1mm, and H1≥50um.

2. The sensor package structure of claim 1, wherein, The first sound hole is a circular hole or a rectangular hole.

3. The sensor package structure of claim 1, wherein, The first sound hole is a circular hole, and the diameter of the circular hole is 0.8mm.

4. The sensor package structure of claim 1, wherein, The first side of the substrate is provided with a mounting groove, the first sound hole is provided at the bottom of the mounting groove, and the waterproof film is provided in the mounting groove. The support sheet is provided at the opening end of the mounting groove, the support sheet is connected with the substrate, the support sheet is provided with a second sound hole penetrating through the thickness direction of the support sheet, the second sound hole is in communication with the mounting groove, the opening area of the second sound hole is less than the area of the effective area, the sensor assembly is provided on the side of the support sheet away from the waterproof film, and the sensor assembly corresponds to the position of the second sound hole; in the axial direction of the first sound hole, the distance between the second sound hole and the effective area is H2, in the radial direction of the first sound hole, the distance between the inner wall surface of the second sound hole and the edge of the effective area is L2, and the ratio of H2 to L2 is greater than 1:

8.

5. The sensor package structure of claim 4, wherein, H1=50um, the ratio of H1 to L1 is 1:1, and / or H2≤50um, the ratio of H2 to L2 is 1:

1.

6. The sensor package structure of claim 4, wherein, The first sound hole and the effective area are centered, and / or the first sound hole and the second sound hole are centered.

7. The sensor package structure of claim 4, wherein, The first sound hole, the effective area and the second sound hole have the same shape.

8. The sensor package structure of claim 7, wherein, The first sound hole is a rectangular hole, the width of the rectangular hole is the minimum radial dimension of the first sound hole, the length of the rectangular hole is d2, and the ratio of d2 to d1 is 2:

1.

9. An electronic device, comprising: The sensor package structure comprises: any one of claims 1 to 8.

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