A MEMS sensor and electronic device

Abstract

The application discloses a MEMS sensor and an electronic device, wherein the MEMS sensor comprises a base, the base comprises a bottom plate, the bottom plate has a first surface and a second surface, and a ventilation passage is formed in the bottom plate and penetrates through the first surface and the second surface, the ventilation passage has a first opening on the first surface and a second opening on the second surface, and a projection of the first opening on a first direction partially overlaps or does not overlap with a projection of the second opening on the first direction; a MEMS chip is fixed to the first surface and covers the first opening. In the MEMS sensor disclosed by the application, when impurities flow in the ventilation passage along with air flow, most of the impurities will be deposited or collided on the inner wall of the ventilation passage due to inertia or gravity, and it is difficult for the impurities to reach the back cavity of the MEMS chip. Meanwhile, the air flow changes direction and experiences a long flow distance in the ventilation passage, and transient impact pressure is significantly attenuated.

Description

Technical Field

[0001] This application relates to the field of MEMS sensor technology, and more particularly to a MEMS sensor and electronic device. Background Technology

[0002] MEMS (Micro-Electro-Mechanical Systems) differential pressure sensors detect pressure changes by sensing the pressure difference across a diaphragm and are widely used in gas detection, industrial process control, automotive electronics, environmental monitoring, and aerospace.

[0003] To enable the diaphragm to establish a pressure path with the outside world or a reference cavity, ventilation holes are often opened on the substrate that holds the MEMS chip during packaging to connect the chip's back cavity with the outside world or a reference cavity.

[0004] However, in the existing solution, directly opening holes in the substrate to connect to the back cavity can easily create hidden dangers: on the one hand, dust and flux splashes and solder beads generated during the soldering process can enter the back cavity through the hole and cause contamination or damage to the MEMS diaphragm; on the other hand, some high-speed short pulses or fluctuating airflows can enter the back cavity through the air hole and apply impact loads to the diaphragm, which may cause the local stress of the diaphragm to exceed its bearing limit, resulting in permanent deformation, cracks or even rupture. Utility Model Content

[0005] This application provides a MEMS sensor and electronic device, which aims to improve the resistance of MEMS sensors to contamination and airflow impact, so as to at least partially solve the above-mentioned technical problems.

[0006] To achieve the above objectives, according to a first aspect of this application, a MEMS sensor is provided, comprising:

[0007] The base includes a base plate, the base plate having a first surface and a second surface disposed opposite to each other along a first direction, the base plate having a ventilation channel penetrating the first surface and the second surface, the ventilation channel having a first opening on the first surface and a second opening on the second surface, the projection of the first opening in the first direction and the projection of the second opening in the first direction partially overlapping or not overlapping.

[0008] A MEMS chip is fixed to the first surface, covering the first opening.

[0009] Optionally, the ventilation channel includes a first through hole penetrating the first surface and the second surface, wherein the axis of the first through hole forms an angle with the first direction.

[0010] Optionally, the ventilation channel includes:

[0011] The first groove is formed on the first surface, and the groove opening is the first opening.

[0012] The second groove is formed on the second surface, and the opening of the second groove is the second opening;

[0013] The first slot and the second slot are connected, and the projection of the first slot in the first direction partially overlaps the projection of the second slot in the first direction.

[0014] Optionally, the ventilation channel includes:

[0015] The third groove is formed on the first surface, and the opening of the third groove is the first opening;

[0016] A fourth groove is formed on the second surface, and the opening of the fourth groove is the second opening;

[0017] The fifth groove is formed on the side wall of the bottom plate and is connected to the third groove and the fourth groove;

[0018] Wherein, the projection of the third groove in the first direction does not overlap with the projection of the fourth groove in the first direction.

[0019] Optionally, the first surface includes a first region and a second region, wherein in the first region, the first surface and the second surface have a first dimension in a first direction, and in the second region, the first surface and the second surface have a second dimension in the first direction, wherein the first dimension is larger than the second dimension;

[0020] The MEMS chip is located in the first region.

[0021] Optionally, a partition is provided on the first surface, the partition is located between the first region and the second region, separating the first region and the second region, and a through hole is provided on the partition.

[0022] Optionally, it also includes an ASIC chip located in the second region.

[0023] Optionally, it further includes: a first pad embedded on the base, one side of a portion of the first pad being exposed in a second region of the first surface and the other side being exposed on the second surface, the ASIC chip being disposed on the first pad and electrically connected to the first pad.

[0024] Optionally, a portion of the first pad is embedded in the first region, and a groove is formed on the first pad located in the first region, with the MEMS chip located in the groove.

[0025] Optionally, it further includes: a plurality of second pads embedded on the base, each second pad including a first part and a second part connected to each other, the first part being exposed on the first surface and the second part being exposed on the second surface, the MEMS chip being electrically connected to the first part of at least one second pad via a lead.

[0026] Optionally, the first surface includes multiple distribution regions, and the distance from the first surface to the second surface along the first direction is different in different distribution regions;

[0027] The first portion of each of the plurality of second pads is exposed in a different distribution area.

[0028] Optionally, the base further includes: a base side plate, which is disposed along the side wall of the base plate and integrally formed with the base plate;

[0029] The MEMS sensor further includes: a cover plate, which is fixedly connected to the base side plate. The cover plate, the base side plate, and the base plate together form a receiving cavity. The cover plate has air holes. The MEMS chip is located in the receiving cavity.

[0030] According to a second aspect of this application, an electronic device is provided, comprising the MEMS sensor described in any one of the foregoing claims.

[0031] In the MEMS sensor of this application embodiment, the projections of the first and second openings of the ventilation channel located on the base plate do not overlap or only partially overlap. This breaks the "straight channel" between the airflow and impurities, forcing the airflow to flow in a tortuous or oblique direction between the two openings, thus lengthening the airflow path. When impurities flow with the airflow inside the ventilation channel, most impurities will settle or collide with the inner wall of the ventilation channel due to inertia or gravity, making it difficult for them to reach the back cavity of the MEMS chip. Therefore, the second opening does not need to be covered with an oil-proof mesh to still achieve the effect of preventing contamination. At the same time, the airflow has to change direction and travel a long flow distance within the ventilation channel, and the transient impact pressure is significantly attenuated. In summary, this application improves the MEMS sensor's resistance to contamination and airflow impact.

[0032] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0033] 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.

[0034] 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.

[0035] Figure 1 This is a schematic diagram of the structure of a base disclosed in an embodiment of this application;

[0036] Figure 2 yes Figure 1 Section at point AA Figure 1 ;

[0037] Figure 3 This is a bottom view of a base disclosed in an embodiment of this application;

[0038] Figure 4 This is a schematic diagram of the structure of the second pad disclosed in an embodiment of this application;

[0039] Figure 5 yes Figure 1 Section at point AA Figure 2 ;

[0040] Figure 6 yes Figure 1 Section at point AA Figure 3 ;

[0041] Figure 7 This is a schematic diagram of the structure of a MEMS sensor disclosed in an embodiment of this application. Figure 1 ;

[0042] Figure 8 This is a schematic diagram of the structure of a MEMS sensor disclosed in an embodiment of this application. Figure 2 .

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Base; 101. Base plate; 1011. First surface; 10111. First area; 10112. Second area; 1012. Second surface; X1. First dimension; X2. Second dimension; 1013. Base side plate;

[0045] 2. MEMS chips;

[0046] 3. Ventilation channel; 301. First opening; 302. Second opening; 303. First through hole; 304. First groove; 305. Second groove; 306. Third groove; 307. Fourth groove; 308. Fifth groove;

[0047] 5. Partition plate; 501. Through hole;

[0048] 6. ASIC chip;

[0049] 7. First pad; 701, groove;

[0050] 8. Second pad; 801. First part; 802. Second part;

[0051] 9. Cover plate; 901. Receiving cavity; 902. Air vent;

[0052] 10. Protective netting. Detailed Implementation

[0053] 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.

[0054] Reference Figure 1 and Figure 2 Embodiment 1 of this application discloses a MEMS sensor, including a base 1 and a MEMS chip 2.

[0055] The base 1 includes a base plate 101, which has a first surface 1011 and a second surface 1012 disposed opposite to each other along a first direction. A ventilation channel 3 is formed on the base plate 101, penetrating the first surface 1011 and the second surface 1012. The ventilation channel 3 has a first opening 301 on the first surface 1011 and a second opening 302 on the second surface 1012. The MEMS chip 2 is fixed to the first surface 1011, covering the first opening 301.

[0056] In Embodiment 1 of this application, the projection of the first opening 301 in the first direction does not overlap with the projection of the second opening 302 in the first direction. Specifically, the ventilation channel 3 includes a first through hole 303 that penetrates the first surface 1011 and the second surface 1012, and the axis of the first through hole 303 has an angle with the first direction.

[0057] In this embodiment, the projections of the first opening 301 and the second opening 302 do not overlap, and the first through-hole 303 is opened at an angle relative to the first direction. External dust, flux spatter, solder beads, and other particles cannot penetrate the ventilation channel 3 along a straight path. When impurities flow obliquely inside the ventilation channel 3 with the airflow, most impurities will settle or collide with the wall of the first through-hole 303 due to inertia or gravity, making it difficult for them to reach the back cavity of the MEMS chip 2. Simultaneously, with the first through-hole 303 angled, the airflow within the first through-hole 303 must change direction and travel a longer flow distance, significantly attenuating transient impact pressure. Compared to a straight through-hole, the angled first through-hole 303 can dissipate the kinetic energy of high-speed short pulses or undulating airflow through multiple frictional dissipations on the channel wall, reducing the direct impact load on the diaphragm of the MEMS chip 2 and reducing the risk of permanent deformation and fatigue cracks. In summary, this embodiment improves the MEMS sensor's resistance to contamination and airflow impact.

[0058] Reference Figure 1 and Figure 2 In the first embodiment of this application, the MEMS sensor also includes a cover plate 9 and an ASIC chip 6. The cover plate 9 is fixedly connected to the base 1, and the cover plate 9 and the base 1 together form a receiving cavity 901. An air hole 902 is provided on the cover plate 9, and the MEMS chip 2 and the ASIC chip 6 are both located in the receiving cavity 901.

[0059] Specifically, the base 1 further includes a base side plate 1013, which is disposed along the side wall of the base plate 101 and integrally formed with the base plate 101. The cover plate 9 is fixedly connected to the base side plate 1013.

[0060] In Embodiment 1 of this application, the first surface 1011 includes a first region 10111 and a second region 10112. In the first region 10111, the first surface 1011 and the second surface 1012 have a first dimension X1 in a first direction, and in the second region 10112, the first surface 1011 and the second surface 1012 have a second dimension X2 in the first direction, wherein the first dimension X1 is larger than the second dimension X2; the MEMS chip 2 is located in the first region 10111, and the ASIC chip 6 is located in the second region 10112.

[0061] In Embodiment 1 of this application, by dividing the first surface 1011 of the base plate 101 into two regions of different heights (first region 10111 and second region 10112), "pre-deposition" of the airflow introduced into the vent 902 on the cover plate 9 is achieved. Specifically, after the cover plate 9 and the base plate 101 are assembled, the projection of the vent 902 in the first direction falls on the lower second region 10112. The airflow entering the accommodating cavity 901 through the vent 902 and the impurities it carries (such as e-liquid droplets in e-cigarette vapor) first act on the first surface 1011 of the second region 10112 and preferentially settle in this recessed area. The remaining airflow is buffered before entering the higher first region 10111, significantly reducing the concentration of contaminants flowing into the first region 10111. The MEMS chip 2 located in the first region 10111 is thus protected from impurity deposition. This improves the cleanliness of the diaphragm surface of the MEMS chip 2, thereby enhancing the sensitivity and long-term stability of the MEMS sensor. In some embodiments, the MEMS sensor also includes a protective mesh 10. The protective net 10 is connected to the cover plate 9 on the side opposite to the receiving cavity 901, covering the vent 902. In other embodiments, the protective net 10 is connected to the cover plate 9 on the side facing the receiving cavity 901, covering the vent 902. Specifically, the protective net 10 and the cover plate 9 can be fixed by means of snap-fit, welding, or bonding. The protective net 10 can prevent larger impurities such as dust, flux spatter, and fumes from entering the receiving cavity 901.

[0062] It is worth mentioning that in the first embodiment of this application, a partition 5 is also provided on the first surface 1011. The partition 5 is located between the first region 10111 and the second region 10112, separating the first region 10111 and the second region 10112. A through hole 501 is provided on the partition 5.

[0063] In this embodiment, the partition 5 physically separates the second region 10112 from the first region 10111. Even if some impurities or droplets accumulate in the second region 10112, they are unlikely to diffuse laterally into the first region 10111, thereby further improving the cleanliness of the diaphragm surface of the MEMS chip 2 in the first region 10111. The through hole 501 connects the first region 10111 and the second region 10112, ensuring that the airflow entering the accommodating cavity 901 through the vent 902 acts on the MEMS chip 2.

[0064] Reference Figure 1 , Figure 3 and Figure 4In Embodiment 1 of this application, the MEMS sensor further includes a first pad 7 and a plurality of second pads 8. The first pad 7 is embedded in the base 1, with a portion of the first pad 7 exposed in the second region 10112. The ASIC chip 6 is disposed on the first pad 7 and electrically connected to the first pad 7. The plurality of second pads 8 are embedded in the base 1, and each second pad 8 includes a first part 801 and a second part 802 connected to each other. The first part 801 is exposed on the first surface 1011, and the second part 802 is exposed on the second surface 1012. The MEMS chip 2 is electrically connected to the first part 801 of at least one second pad 8 via leads. The ASIC chip 6 is electrically connected to the first part 801 of at least one second pad 8 via leads.

[0065] It should be noted that the second pad 8 can be as follows: Figure 4 The U-shaped structure shown can also be other structures, as long as the second pad 8 is partially exposed on the first surface 1011 and partially exposed on the second surface 1012.

[0066] It is worth mentioning that in the first embodiment of this application, the first surface 1011 includes multiple distribution areas, and the distance from the first surface 1011 to the second surface 1012 along the first direction is different in different distribution areas; the first part 801 of the multiple second pads 8 are exposed in different distribution areas respectively.

[0067] In this embodiment, the first pad 7 and the second pad 8 together constitute the metal frame of the MEMS sensor. The first pad 7 and the second pad 8 can be made of copper, aluminum, or a copper-aluminum alloy. The base 1 is formed by injection molding (i.e., the base plate 101 and the base side plate 1013 are integrally formed by injection molding), which encloses the metal frame formed by the first pad 7 and the second pad 8, and exposes the first pad 7 and the second pad 8 on the first surface 1011 and the second surface 1012 for transmitting electrical signals between the MEMS chip 2 and the ASIC chip 6.

[0068] Reference Figure 8 In one embodiment of this application, the first pad 7 has a bent structure. Part of the first pad 7 is located in the second region 10112, exposed both in the accommodating cavity 901 and on the second surface 1012; part of the first pad 7 is located in the first region 10111, and a groove 701 is formed on the first pad 7 in the first region 10111. The MEMS chip 2 is located in the groove 701, and the MEMS chip 2 is electrically connected to at least one second pad 8 in the first region 10111.

[0069] Through the above structural design, the MEMS chip 2 is mounted in the groove 701, reducing the wire bonding height required for the MEMS chip 2's wire bonding. This solution not only helps to reduce the overhang of the bonding wire and lower the risk of breakage when the bonding wire is subjected to vibration or impact, but also improves bonding reliability and the overall long-term stability of the device.

[0070] Reference Figure 5 Embodiment 2 of this application discloses a MEMS sensor. The difference from Embodiment 1 is that the ventilation channel 3 in Embodiment 2 includes a first groove 304 and a second groove 305. The first groove 304 is formed on the first surface 1011, and its opening is a first opening 301. The second groove 305 is formed on the second surface 1012, and its opening is a second opening 302. The first groove 304 and the second groove 305 are connected, and the projection of the first groove 304 in the first direction partially overlaps with the projection of the second groove 305 in the first direction.

[0071] In this embodiment, the projected portions of the first groove 304 and the second groove 305 overlap, which is equivalent to the first groove 304 and the second groove 305 being offset in the first direction and partially connected. The partial overlap of the first groove 304 and the second groove 305 in projection breaks the "straight channel" between the airflow and impurities, forcing the airflow to flow in a tortuous manner between the two openings, thus lengthening the airflow path. Impurity particles or droplets are more likely to settle and be trapped at the turning points due to inertial impact against the groove walls, significantly reducing the risk of entering the back cavity of the MEMS chip 2. Simultaneously, the airflow first enters the second groove 305, then slowly turns through the overlapping area into the first groove 304. The flow velocity and impact pressure are weakened during the cross-sectional change, reducing the transient impact load on the diaphragm of the MEMS chip 2. In summary, this embodiment improves the MEMS sensor's resistance to contamination and airflow impact.

[0072] Reference Figure 6 Embodiment 3 of this application discloses a MEMS sensor, which differs from Embodiment 1 in that the ventilation channel 3 includes a third groove 306, a fourth groove 307, and a fifth groove 308. The third groove 306 is formed on the first surface 1011, and its opening is a first opening 301; the fourth groove 307 is formed on the second surface 1012, and its opening is a second opening 302; the fifth groove 308 is formed on the side wall of the base plate 101 and is connected to the third groove 306 and the fourth groove 307. The projection of the third groove 306 in the first direction does not overlap with the projection of the fourth groove 307 in the first direction.

[0073] In this embodiment, the third groove 306 and the fourth groove 307 do not overlap in projection. The third groove 306 and the fourth groove 307 are connected by the fifth groove 308, breaking the "straight channel" between the airflow and impurities, forcing the airflow to flow in a tortuous manner between the two openings, and extending the airflow path. Impurity particles or droplets are more likely to settle and be trapped at the turning point due to inertial impact on the groove wall, significantly reducing the risk of entering the back cavity of the MEMS chip 2. At the same time, the airflow first enters the fourth groove 307, and then turns through the fifth groove 308 to enter the third groove 306. The flow velocity and impact pressure are gradually weakened in multiple cross-sectional changes, reducing the transient impact load on the diaphragm of the MEMS chip 2. In summary, this embodiment improves the MEMS sensor's resistance to contamination and airflow impact.

[0074] Reference Figure 7 Embodiment 4 of this application also discloses a MEMS sensor. Unlike Embodiment 1, the first region 10111 below the MEMS chip 2 does not have a first pad 7. The first pad 7 is only provided in the second region 10112 of the first surface 1011. The MEMS chip 2 is electrically connected to at least one second pad 8 of the first region 10111 via leads.

[0075] Embodiment 5 of this application discloses an electronic device that includes any of the above-mentioned MEMS sensors. The electronic device may be an electronic cigarette.

[0076] 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.

[0077] 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.

[0078] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0079] 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 MEMS sensor, characterized by, include: The base (1) includes a base plate (101), the base plate (101) having a first surface (1011) and a second surface (1012) arranged opposite to each other along a first direction, the base plate (101) having a ventilation channel (3) that passes through the first surface (1011) and the second surface (1012), the ventilation channel (3) having a first opening (301) on the first surface (1011) and a second opening (302) on the second surface (1012), the projection of the first opening (301) in the first direction and the projection of the second opening (302) in the first direction partially overlap or do not overlap; A MEMS chip (2) is fixed to the first surface (1011) and covers the first opening (301).

2. The MEMS sensor of claim 1, wherein, The ventilation channel (3) includes a first through hole (303) that penetrates the first surface (1011) and the second surface (1012), and the axis of the first through hole (303) has an angle with the first direction.

3. The MEMS sensor according to claim 1, characterized in that, The ventilation channel (3) includes: The first groove (304) is formed on the first surface (1011), and the opening of the first groove (304) is the first opening (301). The second groove (305) is formed on the second surface (1012), and the opening of the second groove (305) is the second opening (302); The first groove (304) and the second groove (305) are connected, and the projection of the first groove (304) in the first direction partially overlaps with the projection of the second groove (305) in the first direction.

4. The MEMS sensor according to claim 1, characterized in that, The ventilation channel (3) includes: The third groove (306) is formed on the first surface (1011), and the opening of the third groove (306) is the first opening (301); The fourth groove (307) is formed on the second surface (1012), and the opening of the fourth groove (307) is the second opening (302); The fifth groove (308) is formed on the side wall of the bottom plate (101) and is connected to the third groove (306) and the fourth groove (307); The projection of the third groove (306) in the first direction does not overlap with the projection of the fourth groove (307) in the first direction.

5. The MEMS sensor according to claim 1, characterized in that, The first surface (1011) includes a first region (10111) and a second region (10112). In the first region (10111), the first surface (1011) and the second surface (1012) have a first dimension X1 in a first direction. In the second region (10112), the first surface (1011) and the second surface (1012) have a second dimension X2 in the first direction. The first dimension X1 is larger than the second dimension X2. The MEMS chip (2) is located in the first region (10111).

6. The MEMS sensor according to claim 5, characterized in that, A partition (5) is provided on the first surface (1011). The partition (5) is located between the first region (10111) and the second region (10112), separating the first region (10111) and the second region (10112). A through hole (501) is provided on the partition (5).

7. The MEMS sensor according to claim 5, characterized in that, It also includes an ASIC chip (6), which is located in the second region (10112).

8. The MEMS sensor according to claim 7, characterized in that, Also includes: The first pad (7) is embedded on the base (1). One side of the first pad (7) is exposed in the second region (10112) of the first surface (1011), and the other side is exposed in the second surface (1012). The ASIC chip (6) is disposed on the first pad (7) and electrically connected to the first pad (7).

9. The MEMS sensor according to claim 8, characterized in that, Part of the first pad (7) is embedded in the first region (10111), and a groove (701) is formed on the first pad (7) in the first region (10111), and the MEMS chip (2) is located in the groove (701).

10. The MEMS sensor according to claim 1, characterized in that, Also includes: Multiple second pads (8) are embedded on the base (1). Each second pad (8) includes a first part (801) and a second part (802) connected to each other. The first part (801) is exposed on the first surface (1011), and the second part (802) is exposed on the second surface (1012). The MEMS chip (2) is electrically connected to the first part (801) of at least one second pad (8) via a lead.

11. The MEMS sensor according to claim 10, characterized in that, The first surface (1011) includes multiple distribution regions, and the distance from the first surface (1011) to the second surface (1012) along the first direction is different in different distribution regions; The first part (801) of the plurality of second pads (8) is exposed in different distribution areas.

12. The MEMS sensor according to claim 1, characterized in that, The base (1) further includes: a base side plate (1013), which is disposed along the side wall of the base plate (101) and integrally formed with the base plate (101); The MEMS sensor further includes: a cover plate (9), which is fixedly connected to the base side plate (1013). The cover plate (9), the base side plate (1013), and the base plate (101) together form a receiving cavity (901). An air hole (902) is provided on the cover plate (9). The MEMS chip (2) is located in the receiving cavity (901).

13. An electronic device, characterized in that, Including the MEMS sensor as described in any one of claims 1-12.

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