A packaging structure of a MEMS chip and an electronic device

Abstract

The application discloses a packaging structure of a MEMS chip and an electronic device, wherein the packaging structure comprises a substrate, a first through hole is formed in the substrate; a dustproof film comprises a first part and a second part connected with each other, the first part is connected with the substrate, and the second part covers the first through hole; a MEMS chip comprises a substrate and a diaphragm, a back cavity penetrating through the thickness of the substrate is formed in the substrate, the diaphragm is fixedly connected with the substrate and covers the back cavity, and the side of the substrate, away from the diaphragm, is fixedly connected with the dustproof film; and a separation film comprises a first separation part which is arranged around the first through hole and extends towards the diaphragm in a direction perpendicular to the substrate, and the first separation part is located in the back cavity. In the application, the adhesive located in the back cavity can climb upwards along the first separation part, the adhesive amount of the adhesive which climbs in the direction of the diaphragm along the inner wall of the substrate is reduced, the adhesive entering the diaphragm area is effectively inhibited, the diaphragm is prevented from being polluted, and thus the performance degradation and even the device failure caused by the pollution of the diaphragm are avoided.

Description

Technical Field

[0001] This application relates to the field of MEMS sensor technology, and in particular to a packaging structure for a MEMS chip and an electronic device. Background Technology

[0002] Micro-Electro-Mechanical Systems (MEMS) sensors are high-performance devices that combine micromechanical structures with microelectronic technology, and are widely used in smart terminals, wearable devices, automotive electronics, and consumer electronics products.

[0003] In existing MEMS sensors, MEMS chips are typically mounted onto a support structure using adhesives. However, in actual production and application, due to the difficulty in precisely controlling process parameters such as adhesive application amount, viscosity, curing performance, and material composition, adhesive overflow may occur before and after curing. When overflowing adhesive flows into the diaphragm area of ​​the MEMS chip, it hinders the free movement of the diaphragm, leading to decreased microphone acoustic sensitivity, increased noise levels, and in severe cases, complete device failure. Utility Model Content

[0004] This application provides a packaging structure and electronic device for a MEMS chip, designed to prevent adhesive overflow from contaminating the diaphragm area of ​​the MEMS chip.

[0005] To achieve the above objectives, according to a first aspect of this application, a packaging structure for a MEMS chip is provided, comprising: The substrate has a first through hole that extends through its own thickness; The dustproof film includes a first part and a second part connected to each other. The first part is fixedly connected to the substrate, and the second part covers the first through hole. The projection of the first part in the direction perpendicular to the substrate surrounds the projection of the second part. A MEMS chip includes a substrate and a diaphragm. A back cavity extending through its own thickness is formed on the substrate. The diaphragm is fixedly connected to the substrate and covers the back cavity. The side of the substrate facing away from the diaphragm is fixedly connected to a dustproof film. The back cavity is connected to a first through hole. The isolation membrane includes a first isolation portion disposed around the first through hole and extending toward the diaphragm in a direction perpendicular to the substrate, the first isolation portion being fixedly connected to the first portion and located within the back cavity.

[0006] Optionally, the dustproof film and the isolation film are integrally formed.

[0007] Optionally, the isolation membrane further includes a second isolation portion, which is connected to one end of the first isolation portion away from the first portion, and the second isolation portion extends toward the inner wall of the substrate.

[0008] Optionally, the distance between the end of the second isolation portion away from the first isolation portion and the inner wall of the substrate is greater than a preset value.

[0009] Optionally, the isolation membrane further includes a stepped portion and a third isolation portion. The stepped portion is connected to the end of the first isolation portion away from the first portion and extends in a direction away from the inner wall of the substrate. The third isolation portion is connected to the end of the stepped portion away from the first isolation portion and extends toward the diaphragm in a direction perpendicular to the substrate.

[0010] Optionally, the distance between the end of the first isolation portion away from the first portion and the inner wall of the substrate is greater than a preset value.

[0011] Optionally, the first isolation portion includes a plurality of first isolation portions, which are arranged sequentially from the side near the edge of the second portion to the side away from the edge of the second portion, and the size of the plurality of first isolation portions in the direction perpendicular to the substrate decreases sequentially from the side near the edge of the second portion to the side away from the edge of the second portion.

[0012] Optionally, the distance from the side surface of the first part away from the substrate to the substrate is equal to the distance from the side surface of the second part away from the substrate to the substrate.

[0013] Optionally, the second part is fixed to one end of the first isolation part away from the first part, and the end face of the first isolation part away from the first part protrudes from the side surface of the second part away from the substrate.

[0014] Optionally, it also includes: The support portion is fixedly connected to the substrate; A thermosetting layer is fixedly connected to the side of the support portion opposite to the substrate; The second through hole penetrates the support portion and the thermosetting layer, and the first through hole and the second through hole are connected. The dustproof film is fixedly connected to the support portion through the thermosetting layer.

[0015] Optionally, it also includes: The housing is fixedly connected to the substrate and forms an accommodating cavity with the substrate; An ASIC chip is fixedly connected to the substrate and located within the accommodating cavity; The MEMS chip is located within the accommodating cavity and is electrically connected to the ASIC chip.

[0016] According to a second aspect of this application, an electronic device is provided, comprising a packaging structure for a MEMS chip as described in any one of the preceding claims.

[0017] In this application, when the MEMS chip is fixedly connected to the substrate by an adhesive, a portion of the adhesive located in the back cavity can climb upward along the first isolation portion, reducing the amount of adhesive climbing towards the diaphragm along the inner wall of the substrate, increasing the difficulty of the adhesive climbing towards the diaphragm, effectively suppressing the adhesive from entering the diaphragm area, and avoiding diaphragm contamination and the resulting performance degradation or even device failure.

[0018] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0020] Figure 1 This is a schematic diagram of the packaging structure of the MEMS chip disclosed in the embodiments of this application. Figure 1 ; Figure 2 This is a schematic diagram of the packaging structure of the MEMS chip disclosed in the embodiments of this application. Figure 2 ; Figure 3 yes Figure 2 A top view of the dustproof film shown; Figure 4 This is a schematic diagram of the packaging structure of the MEMS chip disclosed in the embodiments of this application. Figure 3 ; Figure 5 This is a schematic diagram of the packaging structure of the MEMS chip disclosed in the embodiments of this application. Figure 4 ; Figure 6 This is a schematic diagram of the packaging structure of the MEMS chip disclosed in the embodiments of this application. Figure 5 .

[0021] Explanation of reference numerals in the attached figures: 1. Substrate; 11. First through-hole; 2. Dustproof film; 21. Part One; 22. Part Two; 3. MEMS chip; 31. Substrate; 32. Diaphragm; 33. Back cavity; 4. Separating membrane; 41. First separating section; 42. Second separating section; 43. Stepped section; 44. Third separating section; 5. Support section; 51. Second through hole; 6. Thermosetting layer; 7. Shell; 71. Receiving cavity; 8. ASIC chip; 9. Lead wire. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0023] As described in the background art, when a MEMS chip is mounted on a support structure using an adhesive, the adhesive's coating amount, viscosity, curing performance, and material composition are difficult to control precisely. As a result, the adhesive tends to climb up the inner wall of the MEMS chip substrate under capillary action before and after curing and enter the diaphragm area of ​​the MEMS chip. This restricts the free movement of the diaphragm, leading to a decrease in the sensitivity of the MEMS chip, an increase in noise level, and in severe cases, even device failure.

[0024] To prevent adhesive overflow from contaminating the diaphragm area of ​​the MEMS chip, this application discloses a packaging structure for a MEMS chip.

[0025] Reference Figure 1In some embodiments, the packaging structure of the MEMS chip includes: a substrate 1, a dustproof film 2, a MEMS chip 3, and an isolation film 4. The substrate 1 has a first through-hole 11 extending through its own thickness. The dustproof film 2 includes a first portion 21 and a second portion 22 connected together. The first portion 21 is fixedly connected to the substrate 1, and the second portion 22 covers the first through-hole 11. The projection of the first portion 21 in a direction perpendicular to the substrate 1 surrounds the projection of the second portion 22. The MEMS chip 3 includes a substrate 31 and a diaphragm 32. A back cavity 33 extending through its own thickness is formed on the substrate 31. The diaphragm 32 is fixedly connected to the substrate 31 and covers the back cavity 33. The side of the substrate 31 facing away from the diaphragm 32 is fixedly connected to the dustproof film 2, and the back cavity 33 communicates with the first through-hole 11. The isolation film 4 includes a first isolation portion 41 surrounding the first through-hole 11 and extending toward the diaphragm 32 in a direction perpendicular to the substrate 1. The first isolation portion 41 is fixedly connected to the first portion 21 and located within the back cavity 33.

[0026] In this embodiment, when the MEMS chip 3 is fixedly connected to the substrate 1 by an adhesive, a portion of the adhesive located in the back cavity 33 can climb upward along the first isolation portion 41, reducing the amount of adhesive climbing upward along the inner wall of the substrate 31 toward the diaphragm 32, increasing the difficulty of the adhesive climbing toward the diaphragm 32, effectively suppressing the adhesive from entering the diaphragm 32 area, and avoiding contamination of the diaphragm 32 and the resulting performance degradation or even device failure.

[0027] In some embodiments, there is a gap between the first isolation portion 41 and the diaphragm 32.

[0028] Furthermore, continue to refer to Figure 1 In some embodiments, the MEMS chip packaging structure further includes a support portion 5, a thermosetting layer 6, and a second through-hole 51. The support portion 5 is fixedly connected to the substrate 1. In some embodiments, the support portion 5 is fixedly connected to the substrate 1 by an adhesive. The thermosetting layer 6 is fixedly connected to the side of the support portion 5 away from the substrate 1. The second through-hole 51 penetrates the support portion 5 and the thermosetting layer 6, and the first through-hole 11 and the second through-hole 51 are connected. The dustproof film 2 is fixedly connected to the support portion 5 through the thermosetting layer 6. In other words, the dustproof film 2 is fixed to the substrate 1 by the thermosetting layer 6 and the support portion 5. The second part 22 of the dustproof film 2 is a mesh film structure. The dustproof film 2 is located between the substrate 1 and the MEMS chip 3, and can effectively prevent foreign objects from entering the back cavity 33 of the MEMS chip 3 through the first through-hole 11 and the second through-hole 51.

[0029] In some embodiments, the dustproof film 2 and the isolation film 4 are integrally formed. Specifically, during the preparation of the dustproof film 2, by etching the material of the dustproof film 2, a mesh-like second part 22 for blocking the entry of external foreign objects and a first isolation part 41 extending toward the diaphragm 32 in a direction perpendicular to the substrate 1 can be formed simultaneously, thereby achieving an integrated layout of the isolation film 4 structure without adding additional assembly steps.

[0030] Continue to refer to Figure 1 In some embodiments, the distance between the side surface of the first part 21 facing away from the substrate 1 and the side surface of the second part 22 facing away from the substrate 1 is equal. The end face of the first isolation part 41 facing away from the first part 21 protrudes from the side surface of the first part 21 facing away from the substrate 1 in a direction away from the substrate 1, and also protrudes from the side surface of the second part 22 facing away from the substrate 1.

[0031] With the above structural arrangement, the first isolation portion 41 is higher than the first portion 21 and the second portion 22 in the direction away from the substrate 1. When the MEMS chip 3 is fixedly connected to the substrate 1 by adhesive, the first isolation portion 41 can guide and disperse the adhesive located in the back cavity 33, reducing the possibility of the adhesive continuing to climb towards the diaphragm 32 along the inside of the back cavity 33. On the other hand, it can effectively isolate the adhesive from the second portion 22, preventing adhesive overflow from blocking the mesh structure of the second portion 22 and ensuring that the sound transmission performance of the dustproof film 2 is not affected.

[0032] In some embodiments, the MEMS chip packaging structure further includes a housing 7 and an ASIC chip 8. The housing 7 is fixedly connected to the substrate 1 and forms a receiving cavity 71 with the substrate 1. The ASIC chip 8 is fixedly connected to the substrate 1 and is located within the receiving cavity 71. The MEMS chip 3 is also located within the receiving cavity 71. In some embodiments, the substrate 1 is a circuit board, and the MEMS chip 3 is electrically connected to the ASIC chip 8 via leads 9, and the ASIC chip 8 is electrically connected to the substrate 1 via leads 9 to realize the transmission of electrical signals.

[0033] Reference Figure 2 In some embodiments, the second part 22 is fixed to the end of the first isolation part 41 opposite to the first part 21, and the end face of the first isolation part 41 opposite to the first part 21 protrudes from the side surface of the second part 22 opposite to the substrate 1. In this embodiment, before and after the adhesive cures, the first isolation part 41 can guide and disperse the adhesive located in the back cavity 33, reducing the possibility of the adhesive continuing to climb towards the diaphragm 32 along the inside of the back cavity 33. On the other hand, it can prevent adhesive overflow from blocking the sound-transmitting structure of the second part 22, ensuring the sound transmission performance and acoustic transmission stability of the dustproof membrane 2.

[0034] It should be noted that in the above embodiments, the first isolation portion 41 is arranged around the first through hole 11, forming a ring structure. (Refer to...) Figure 3 The first isolation part 41 is an annular structure that can form a continuous guiding path in the entire circumference of the back cavity 33, so that the adhesive at any position on the inner wall of the substrate 31 can be guided by the first isolation part 41 as it climbs along the inner wall of the substrate 31, thereby achieving full circumferential restriction and dispersion of adhesive overflow.

[0035] Reference Figure 4 In some embodiments, the isolation membrane 4 further includes a second isolation portion 42, which is connected to the end of the first isolation portion 41 opposite to the first portion 21, and extends toward the inner wall of the substrate 31. It should be noted that the second isolation portion 42 is also annular, and is fixedly connected to the first isolation portion 41 along its edge. In some embodiments, the second isolation portion 42 and the first isolation portion 41 are integrally formed.

[0036] In some embodiments, the distance between the end of the second isolation portion 42 facing away from the first isolation portion 41 and the inner wall of the substrate 31 is greater than a preset value. When the adhesive climbs along the inner wall of the substrate 31 to the height of the second isolation portion 42, some of the adhesive can be guided onto the second isolation portion 42. In some embodiments, the preset value ranges from [50, 100] micrometers.

[0037] It should be noted that in some embodiments, the first isolation portion 41 and the third isolation portion 44 are integrally formed.

[0038] With the above configuration, the second isolation section 42 can change the climbing path of the adhesive on the inner wall of the substrate 31, intercept and divert the adhesive that has climbed to the height of the second isolation section 42, thereby preventing some adhesive from crossing the second isolation section 42 and continuing to diffuse towards the diaphragm 32, and reducing the amount of adhesive climbing upward along the inner wall of the substrate 31, further improving the protective effect of the isolation film 4 on the diaphragm 32 area.

[0039] Reference Figure 5 In some embodiments, the isolation membrane 4 further includes a stepped portion 43 and a third isolation portion 44. The stepped portion 43 is connected to the end of the first isolation portion 41 away from the first portion 21. The stepped portion 43 extends in a direction away from the inner wall of the substrate 31. The third isolation portion 44 is connected to the end of the stepped portion 43 away from the first isolation portion 41 and extends toward the diaphragm 32 in a direction perpendicular to the substrate 1.

[0040] It should be noted that in some embodiments, the first isolation portion 41, the stepped portion 43, and the third isolation portion 44 are integrally formed.

[0041] In some embodiments, the distance between the end of the first isolation portion 41 facing away from the first portion 21 and the inner wall of the substrate 31 is greater than a preset value. When the adhesive climbs along the inner wall of the substrate 31 to the height of the end of the first isolation portion 41 facing away from the first portion 21, it will be obstructed at the gap between the end of the first isolation portion 41 facing away from the first portion 21 and the inner wall of the substrate 31 and flow towards the stepped portion 43. After the adhesive enters the stepped portion 43, the driving force for the adhesive to continue climbing is significantly reduced because the flow path is horizontally shifted and the direct climbing contact area with the inner wall is reduced. Furthermore, for the adhesive that still has a climbing tendency on the stepped portion 43, part of it climbs along the third isolation portion 44 and part of it climbs along the inner wall of the substrate 31. In this way, the third isolation portion 44 can intercept and disperse the adhesive again, further reducing the amount of adhesive that continues to climb along the inner wall of the substrate 31. In some embodiments, the preset value ranges from [50, 100] micrometers.

[0042] Thus, through the above solution, the isolation membrane 4 can change and extend the adhesive climbing path, effectively cutting off the fast path of the adhesive from the inner wall of the substrate 31 to the diaphragm 32, significantly reducing the risk of the adhesive entering the diaphragm 32 area, ensuring that the free vibration space of the diaphragm 32 is not encroached, and at the same time preventing the adhesive from overflowing into the second part 22 of the dustproof membrane 2.

[0043] Reference Figure 6 In some embodiments, the first isolation portion 41 includes a plurality of first isolation portions 41, which are arranged sequentially from the side near the edge of the second portion 22 to the side away from the edge of the second portion 22. The size of the plurality of first isolation portions 41 in the direction perpendicular to the substrate 1 decreases sequentially from the side near the edge of the second portion 22 to the side away from the edge of the second portion 22.

[0044] The height of the first isolation section 41 decreases gradually from the outside to the inside, which increases the resistance to the adhesive climbing upwards, making it difficult for the adhesive to cross each level of the first isolation section 41 and directly invade the sensitive area around the diaphragm 32.

[0045] In some embodiments, adjacent first isolation portions 41 are spaced apart; in another embodiment, adjacent first isolation portions 41 are fitted together. All of the first isolation portions 41 are fixedly connected to the first portion 21.

[0046] In some embodiments, a plurality of first isolation portions 41, first portions 21 and second portions 22 are integrally formed.

[0047] This application also discloses an electronic device whose packaging structure includes any of the above-mentioned MEMS chips.

[0048] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0049] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0050] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0051] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A packaging structure for a MEMS chip, characterized in that, include: The substrate (1) has a first through hole (11) that extends through its own thickness. The dustproof film (2) includes a first part (21) and a second part (22) connected to each other. The first part (21) is fixedly connected to the substrate (1), and the second part (22) covers the first through hole (11). The projection of the first part (21) in the direction perpendicular to the substrate (1) surrounds the projection of the second part (22). MEMS chip (3) includes a substrate (31) and a diaphragm (32). A back cavity (33) penetrating its own thickness is formed on the substrate (31). The diaphragm (32) is fixedly connected to the substrate (31) and covers the back cavity (33). The side of the substrate (31) away from the diaphragm (32) is fixedly connected to the dustproof film (2). The back cavity (33) is connected to the first through hole (11). The isolation membrane (4) includes a first isolation portion (41) disposed around the first through hole (11) and extending toward the diaphragm (32) in a direction perpendicular to the substrate (1). The first isolation portion (41) is fixedly connected to the first portion (21) and is located in the back cavity (33).

2. The packaging structure of the MEMS chip according to claim 1, characterized in that, The dustproof film (2) and the isolation film (4) are integrally formed.

3. The packaging structure of the MEMS chip according to claim 1, characterized in that, The isolation membrane (4) further includes a second isolation portion (42), which is connected to the end of the first isolation portion (41) away from the first portion (21), and the second isolation portion (42) extends toward the inner wall of the substrate (31).

4. The packaging structure of the MEMS chip according to claim 3, characterized in that, The distance between the end of the second isolation portion (42) away from the first isolation portion (41) and the inner wall of the substrate (31) is greater than a preset value.

5. The packaging structure of the MEMS chip according to claim 1, characterized in that, The isolation membrane (4) further includes a stepped portion (43) and a third isolation portion (44). The stepped portion (43) is connected to the end of the first isolation portion (41) away from the first portion (21) and extends in a direction away from the inner wall of the substrate (31). The third isolation portion (44) is connected to the end of the stepped portion (43) away from the first isolation portion (41) and extends in a direction perpendicular to the substrate (1) toward the diaphragm (32).

6. The packaging structure of the MEMS chip according to claim 5, characterized in that, The distance between the end of the first isolation portion (41) away from the first portion (21) and the inner wall of the substrate (31) is greater than a preset value.

7. The packaging structure of the MEMS chip according to claim 1, characterized in that, The first isolation portion (41) includes a plurality of first isolation portions (41) arranged sequentially from the side near the edge of the second portion (22) to the side away from the edge of the second portion (22), and the size of the plurality of first isolation portions (41) in the direction perpendicular to the substrate (1) decreases sequentially from the side near the edge of the second portion (22) to the side away from the edge of the second portion (22).

8. The packaging structure of the MEMS chip according to any one of claims 1 to 7, characterized in that, The distance from the side surface of the first part (21) away from the substrate (1) to the substrate (1) is equal to the distance from the side surface of the second part (22) away from the substrate (1) to the substrate (1).

9. The packaging structure of the MEMS chip according to claim 1, characterized in that, The second part (22) is fixed to one end of the first isolation part (41) away from the first part (21), and the end face of the first isolation part (41) away from the first part (21) protrudes from the side surface of the second part (22) away from the substrate (1).

10. The packaging structure of the MEMS chip according to any one of claims 1 to 7, characterized in that, Also includes: The support part (5) is fixedly connected to the substrate (1); The thermosetting layer (6) is fixedly connected to the side of the support portion (5) away from the substrate (1); The second through hole (51) penetrates the support part (5) and the thermosetting layer (6), and the first through hole (11) and the second through hole (51) are connected; The dustproof film (2) is fixedly connected to the support part (5) through the thermosetting layer (6).

11. The packaging structure of the MEMS chip according to claim 1, characterized in that, Also includes: The housing (7) is fixedly connected to the substrate (1) and surrounds the substrate (1) to form an accommodating cavity (71). An ASIC chip (8) is fixedly connected to the substrate (1) and located inside the accommodating cavity (71); The MEMS chip (3) is located inside the accommodating cavity (71) and is electrically connected to the ASIC chip (8).

12. An electronic device, characterized in that, The packaging structure includes the MEMS chip as described in any one of claims 1 to 11.

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