COB packaging differential pressure sensor module

Abstract

The utility model relates to a COB packaging differential pressure sensor module. The packaging structure comprises a substrate, a baffle structure fixed at the top of the substrate, a filling cavity arranged at the inner side of the baffle structure, a partition plate fixed at the top of the substrate and dividing the filling cavity into a first chamber and a second chamber, a first chip arranged in the first chamber, and a second chip arranged in the second chamber, the second chip is arranged in the second cavity and is electrically connected with the first chip; the through hole penetrates through the substrate and is communicated with the back cavity of the first chip; according to the utility model, the filling cavity is divided into the first chamber and the second chamber through the partition plate, the first chip and the second chip are packaged in an isolated manner, the dispensing amount is reduced, the cost is reduced, the areas of the first chamber and the second chamber are smaller, defoaming is easy, and the sealing performance and the waterproof performance of the first pouring sealant and the second pouring sealant are ensured. And moreover, the encapsulation glue of the first chip and the second chip can be flexibly changed according to a test medium and cost requirements, so that the universality is higher, and the applicable environment is more variable.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the micro electromechanical system technical field, concretely relates to a COB encapsulation differential pressure sensor module. BACKGROUND

[0002] The differential pressure sensor is a sensor for measuring the difference between two pressures, and is usually used to measure the pressure difference between the front and back of a device or component.

[0003] The utility model discloses a differential pressure sensor packaging structure with the application number "202122637584.1", the utility model discloses a waterproof differential pressure sensor with the application number "201822197013.9", and the utility model discloses a waterproof differential pressure sensor with the application number "202123027140.2". In the above three patents, the MEMS chip and the ASIC chip are packaged in the same packaging space, then sealing glue is poured on the MEMS chip and the ASIC chip, and finally the pressure difference at both ends is transmitted to the ASIC chip for transmission through the MEMS chip.

[0004] The existing COB encapsulation differential pressure sensor module packages the MEMS chip and the ASIC chip in the same packaging space, then pours sealing glue on the MEMS chip and the ASIC chip, the amount of sealing glue poured in the packaging space is relatively large, which causes waste of cost, the packaging space area is relatively large, and it is not easy to remove bubbles, the performance of the sensor is affected by residual bubbles, and only one kind of sealing glue can be poured on the MEMS chip and the ASIC chip, the sealing glue cannot be properly adjusted and replaced according to the external test environment, and the limitation is too large. UTILITY MODEL CONTENTS

[0005] The utility model provides a COB encapsulation differential pressure sensor module, solves the defect that the existing COB encapsulation differential pressure sensor module packages the MEMS chip and the ASIC chip in the same packaging space, causes cost increase caused by large pouring amount, large packaging space area, not easy to remove bubbles and unable to properly adjust the sealing glue according to the external test environment, and too large limitation.

[0006] To achieve the above purpose, the utility model adopts the technical scheme of a COB encapsulation differential pressure sensor module, which comprises:

[0007] A substrate, a baffle structure fixed on top of the substrate, a perfusion cavity arranged inside the baffle structure, a partition plate fixed on top of the substrate and separating the perfusion cavity into a first chamber and a second chamber, a first chip arranged in the first chamber, a second chip arranged in the second chamber and electrically connected with the first chip, and a through hole penetrating through the substrate and communicating with a back cavity of the first chip;

[0008] The first chip is a first pressure sensing side away from the substrate, and the substrate is provided with a through hole as a second pressure sensing side.

[0009] Optimally, it further comprises a first potting glue filled in the first chamber and a second potting glue filled in the second chamber, the first potting glue covering the first chip, and the second potting glue covering the second chip.

[0010] Optimally, the baffle structure comprises a first outer baffle arranged oppositely along a first direction and a second outer baffle arranged oppositely along a second direction, the first outer baffle and the second outer baffle being connected end to end to enclose the perfusion cavity into a closed cavity.

[0011] Optimally, it further comprises a first pad and a second pad fixed on top of the substrate, a first lead connecting the first chip and the first pad, and a second lead connecting the second chip and the second pad, the first pad being arranged in the first chamber, and the second pad being arranged in the second chamber.

[0012] Optimally, the substrate, the first outer baffle, the second outer baffle and the partition plate are made of ceramic.

[0013] Optimally, the first potting glue is silicone or fluorine glue, and the second potting glue is epoxy glue.

[0014] Optimally, the partition plate is fixed between the second outer baffles and parallel to the first outer baffle, and the first chamber and the second chamber have equal projected areas on the substrate.

[0015] Optimally, the first chip is a MEMS chip, and the second chip is an ASIC chip.

[0016] Thanks to the above technical solution, the present application has the following advantages compared with the prior art:

[0017] The COB packaged differential pressure sensor module of the present application takes the first potting glue as a first pressure sensing side to sense pressure change, and converts the pressure change into a deformation variable and transmits the deformation variable to the first chip; the through hole is a second pressure sensing side, external gas directly acts on the back side of the first chip through the through hole, the first chip converts the pressure difference deformation variable caused by the pressure difference between the two sides of the first pressure sensing side and the second pressure sensing side into an analog signal and transmits the analog signal to the second chip, and finally the compensation pressure signal obtained by the second chip is transmitted to an external device.

[0018] The perfusion cavity is divided into the first chamber and the second chamber by the partition plate, the first chip and the second chip are isolated and packaged, the second chip is filled with epoxy glue, and the first chip is filled with silicone glue or fluorine glue, so that the amount of glue dispensing is reduced, the cost is reduced, the areas of the first chamber and the second chamber are smaller, and the first perfusion glue and the second perfusion glue are easy to deaerate, so that the sealing performance and waterproof performance of the first perfusion glue and the second perfusion glue are ensured. Moreover, the perfusion glue of the first chip and the second chip can be flexibly changed according to test medium and cost requirements, the universality is higher, and the applicable environment is more variable. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a sectional view of the utility model;

[0020] Figure 2 It is a top view of the utility model;

[0021] BRIEF DESCRIPTION OF DRAWINGS:

[0022] 1, substrate; 2, first outer baffle; 3, second outer baffle; 4, perfusion cavity; 5, partition plate; 6, first chamber; 7, second chamber; 8, first chip; 9, second chip; 10, first lead; 11, second lead; 12, through hole; 13, first perfusion glue; 14, second perfusion glue; 15, first pad; 16, second pad. DETAILED DESCRIPTION

[0023] The utility model will be further described in connection with the embodiment shown in the drawings.

[0024] As Figure 1 , 2 As shown in the utility model COB package differential pressure sensor module's schematic diagram, this structure includes substrate 1, baffle structure, perfusion cavity 4, partition plate 5, first chamber 6, second chamber 7, first chip 8, second chip 9, first lead 10, second lead 11, through hole 12, first perfusion glue 13, second perfusion glue 14, first pad 15 and second pad 16. Substrate 1 is as support base plate, its shape can be rectangle, square, circle, oval and like, in this embodiment, the shape of rectangle is preferred. The material of substrate 1 is ceramic, utilizes ceramic wear resistance, high temperature resistance, corrosion resistance and the advantages of good chemical stability, improves the compatibility of COB differential pressure sensor module medium, ensures that it can be used for testing weak acid weak base or other corrosive medium (in actual test, according to test medium and cost requirement, substrate 1 of ceramic material is replaced with PCB board).

[0025] Baffle structure is fixed at the top of substrate 1, and perfusion cavity 4 is formed on the inner side of baffle structure, which plays a protective role on the first chip 8 and the second chip 9 in the interior. After the perfusion glue is filled into the perfusion cavity 4, the leakage of the perfusion glue is avoided.

[0026] The baffle structure comprises a first outer baffle 2 and a second outer baffle 3, the first outer baffle 2 has two pieces, which are fixed oppositely on the top of the substrate 1 and arranged along a first direction, and the second outer baffle 3 also has two pieces, which are fixed oppositely on the top of the substrate 1 and arranged along a second direction, the first direction is X-axis, and the second direction is Y-axis. Therefore, the first outer baffle 2 and the second outer baffle 3 are arranged perpendicularly.

[0027] As shown in the figure, Figure 2 The first outer baffle 2 and the second outer baffle 3 are connected end to end, so as to enclose the internal pouring cavity 4 into a closed cavity, and the pouring of the potting adhesive into the pouring cavity 4 can avoid the leakage of the potting adhesive.

[0028] As shown in the figure, Figure 2 The projection area of the baffle structure in the vertical direction of the substrate 1 is less than the area of the substrate 1, and the distance between the outer sides of the two pieces of the first outer baffle 2 is less than the length of the substrate 1, and the distance between the outer sides of the two pieces of the second outer baffle 3 is less than the width of the substrate 1. While ensuring the stability of the structure of the substrate 1, after the potting adhesive is poured into the pouring cavity 4, the leakage of the potting adhesive from the gap between the baffle structure and the substrate 1 is avoided.

[0029] The partition plate 5 is fixed between the two pieces of the second outer baffle 3 and arranged parallel to the first outer baffle 2, the partition plate 5 divides the pouring cavity 4 into a first chamber 6 and a second chamber 7, and the projection areas of the first chamber 6 and the second chamber 7 in the vertical direction on the substrate 1 are the same. After the potting adhesive is poured into the first chamber 6 and the second chamber 7, the influence on the detection result caused by the different amounts of pouring of the two is avoided.

[0030] The materials of the first outer baffle 2, the second outer baffle 3 and the partition plate 5 are ceramic, which takes advantage of the good chemical stability, wear resistance, high temperature resistance and corrosion resistance of ceramic to improve the compatibility of the COB differential pressure sensor module medium, so as to ensure that it can be used to test weak acid, weak base or other corrosive medium.

[0031] The first chip 8 is arranged in the first chamber 6, and the second chip 9 is arranged in the second chamber 7 and electrically connected with the first chip 8 (in this embodiment, the first chip 8 is a pressure chip, i.e. a MEMS chip, and the second chip 9 is an ASIC chip). The first potting adhesive 13 is poured into the first chamber 6 and covers the first chip 8, and the second potting adhesive 14 is poured into the second chamber 7 and covers the second chip 9. The coverage of the first chip 8 and the second chip 9 includes side coverage and top coverage, which plays a protective role for the covered first chip 8 and second chip 9, and at the same time can effectively sense the change of external pressure, forming a micro deformation on the first chip 8.

[0032] The first potting glue 13 is fluorine glue or silicon glue, improves the compatibility of the medium, can be used for testing corrosive medium such as weak acid and weak base, and can be switched between fluorine glue and silicon glue according to the test medium and cost requirements.

[0033] The potting cavity 4 is divided into the first chamber 6 and the second chamber 7 with equal areas by the partition plate 5, the first chip 8 and the second chip 9 are isolated and packaged, the second chip 9 is filled with epoxy glue, and the first chip 8 is filled with silicon glue or fluorine glue, so that the glue dispensing amount is reduced, the cost is reduced, the areas of the first chamber 6 and the second chamber 7 are smaller, and the first chamber 6 and the second chamber 7 are easy to deaerate, so that the sealing performance and waterproof performance of the first potting glue 13 and the second potting glue 14 are ensured.

[0034] The height of the partition plate 5 is equal to the height of the first outer baffle 2 and the second outer baffle 3, so that the first potting glue 13 in the first chamber 6 is prevented from being transferred into the second chamber 7 due to the too low partition plate 5, or interference occurs in the subsequent assembly process due to the too high partition plate 5.

[0035] The through hole 12 penetrates the substrate 1 and communicates with the back cavity of the first chip 8, as shown in Figure 1 The side, away from the substrate 1, of the first potting glue 13 is a first pressure sensing side, and the side, on which the through hole 12 of the substrate 1 is opened, is a second pressure sensing side. In actual use, the first potting glue 13 serves as the first pressure sensing side to sense pressure changes and transfer the pressure changes to the first chip 8 in the form of deformation; the through hole 12 serves as the second pressure sensing side, external gas directly acts on the back side of the first chip 8 through the through hole 12, the first chip 8 converts the pressure difference deformation caused by the pressure difference between the two sides of the first pressure sensing side and the second pressure sensing side into an analog signal and transmits the analog signal to the second chip 9, the second chip 9 converts the received analog signal into a digital pressure signal, and performs signal amplification, calibration and other processing, and performs temperature compensation on the digital pressure signal according to the pre-stored temperature coefficient to realize the temperature linear compensation function, and obtains a compensated pressure signal which is transmitted to an external device.

[0036] The first pad 15 and the second pad 16 are fixed on the top of the substrate 1, the first pad 15 is located in the first chamber 6, and the second pad 16 is located in the second chamber 7, the first lead 10 is used for connecting the first chip 8 and the first pad 15, and the second lead 11 is used for connecting the second chip 9 and the second pad 16, so that the pads are convenient for being connected with external devices.

[0037] The first lead 10 and the second lead 11 can be copper wire, aluminum wire or gold wire.

[0038] The test principle of the COB packaged differential pressure sensor module is as follows:

[0039] The first potting glue 13 serves as a first pressure sensing side to sense pressure change and transfer the pressure change to the first chip 8 in the form of deformation; the through hole 12 serves as a second pressure sensing side, and external gas directly acts on the back side of the first chip 8 through the through hole 12, the first chip 8 converts the pressure difference deformation caused by the pressure difference between the two sides of the first pressure sensing side and the second pressure sensing side into an analog signal and transmits the analog signal to the second chip 9, and finally the compensation pressure signal obtained by the second chip 9 is transmitted to an external device;

[0040] The potting cavity 4 is divided into the first chamber 6 and the second chamber 7 by the partition plate 5, the first chip 8 and the second chip 9 are isolated and packaged, the second chip 9 is filled with epoxy glue, and the first chip 8 is filled with silicone glue or fluorine glue, so that the amount of glue dispensing is reduced, the cost is reduced, the areas of the first chamber 6 and the second chamber 7 are smaller, and the first chamber 6 and the second chamber 7 are easy to deaerate, so as to ensure the sealing performance and waterproof performance of the first potting glue 13 and the second potting glue 14. Moreover, according to the test medium and the cost requirement, the potting glue of the first chip 8 and the second chip 9 can be flexibly changed, the versatility is higher, and the applicable environment is more variable.

[0041] The above examples are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A COB packaged differential pressure sensor module, characterized by, It comprises: a substrate (1), a baffle structure fixed on the top of the substrate (1), a perfusion cavity (4) arranged inside the baffle structure, a partition plate (5) fixed on the top of the substrate (1) and separating the perfusion cavity (4) into a first chamber (6) and a second chamber (7), a first chip (8) arranged in the first chamber (6), a second chip (9) arranged in the second chamber (7) and electrically connected with the first chip (8), and a through hole (12) penetrating through the substrate (1) and communicating with the back cavity of the first chip (8); the side of the first chip (8) away from the substrate (1) is a first pressure sensing side, and the side of the substrate (1) with the through hole (12) is a second pressure sensing side.

2. The COB packaged differential pressure sensor module of claim 1, wherein: It further comprises a first potting glue (13) filled in the first chamber (6) and a second potting glue (14) filled in the second chamber (7), the first potting glue (13) covering the first chip (8), and the second potting glue (14) covering the second chip (9).

3. The COB packaged differential pressure sensor module of claim 1, wherein: The baffle structure comprises a first outer baffle (2) arranged oppositely along a first direction and a second outer baffle (3) arranged oppositely along a second direction, the first outer baffle (2) and the second outer baffle (3) being connected end to end to enclose the perfusion cavity (4) into a closed cavity.

4. The COB packaged differential pressure sensor module of claim 1, wherein: It further comprises a first pad (15) and a second pad (16) fixed on the top of the substrate (1), a first lead wire (10) connecting the first chip (8) and the first pad (15), and a second lead wire (11) connecting the second chip (9) and the second pad (16), the first pad (15) being arranged in the first chamber (6), and the second pad (16) being arranged in the second chamber (7).

5. The COB packaged differential pressure sensor module of claim 3, wherein: The substrate (1), the first outer baffle (2), the second outer baffle (3) and the partition plate (5) are made of ceramic.

6. The COB packaged differential pressure sensor module of claim 2, wherein: The first potting glue (13) is silicone or fluorine glue, and the second potting glue (14) is epoxy glue.

7. The COB packaged differential pressure sensor module of claim 3, wherein: The partition plate (5) is fixed between the second outer baffles (3) and parallel to the first outer baffle (2), and the projection areas of the first chamber (6) and the second chamber (7) on the substrate (1) are equal.

8. The COB packaged differential pressure sensor module of claim 1, wherein: The first chip (8) is a MEMS chip, and the second chip (9) is an ASIC chip.

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