Hermetic package structure for a device with a cavity

Abstract

The application provides airtight packaging structure of a cavity device, which comprises a semiconductor substrate, a first semi-open cavity is arranged on the front surface of the semiconductor substrate; a micro-electro-mechanical system layer is arranged above the front surface of the semiconductor substrate, a first region of the micro-electro-mechanical system layer and the first semi-open cavity form a first closed cavity; a displacement sensor is arranged in the first closed cavity; a cover plate is arranged above the micro-electro-mechanical system layer, a second semi-open cavity is arranged on the front surface of the cover plate at the position opposite to the first region of the micro-electro-mechanical system layer, and the second semi-open cavity and the first region of the micro-electro-mechanical system layer form a second closed cavity; and a bonding layer is arranged between the micro-electro-mechanical system layer and the cover plate, which is used for bonding the micro-electro-mechanical system layer and the cover plate together and sealing the second closed cavity. Compared with the prior art, the application can identify abnormal air leakage and air release of the cavity in the MEMS manufacturing process, provide basis for the improvement of the MEMS performance, improve the yield and reduce the cost.

Description

[0001] The present application belongs to the field of MEMS (Micro-Electro-Mechanical System) devices, and particularly relates to a hermetic packaging structure of a cavity device.

[0002] Unlike integrated ICs, many MEMS structures work in a vacuum cavity, and the vacuum degree is directly related to the final performance of the sensor. At present, the reduction of the vacuum degree in the MEMS structure mainly involves the leakage at the wafer bonding and the outgassing inside the packaging cavity. How to identify and eliminate the abnormal leakage and outgassing of the cavity in the MEMS manufacturing process is an important way to improve the vacuum degree of the cavity and improve the performance of the sensor. Once determined, corresponding improvements can be made. However, such problems are extremely challenging because the existing vacuum structures (such as gyroscopes, accelerometers, etc.) cannot easily distinguish the vacuum changes caused by leakage and outgassing. And it is very difficult to analyze the failure of such devices, especially in the case of leakage and outgassing.

[0003] In addition, the traditional packaging method adopts a single gas sealing pressure, and different types of MEMS devices have different ideal working gas pressures. For example, for a MEMS accelerometer, in order to maintain high performance and reliability, the working gas pressure is relatively high. And for a MEMS gyroscope, in order to ensure high sensitivity and low power consumption, the working gas pressure is relatively low. The current packaging method cannot meet the packaging requirements of different gas pressures when packaging different types of MEMS devices on the same wafer.

[0004] Therefore, it is necessary to provide a new technical scheme to overcome the above problems.

[0005] One of the purposes of the present application is to provide a hermetic packaging structure of a cavity device, which can identify the abnormal leakage and outgassing of the cavity in the MEMS manufacturing process, provide a basis for improving the performance of the MEMS, improve the yield, and reduce the cost.

[0006] ​​​According to one aspect of the present application, a hermetic package structure of a cavity device is provided, which comprises: a semiconductor substrate, a first semi-open cavity being arranged on a front surface of the semiconductor substrate; a micro-electro-mechanical system (MEMS) layer, which is arranged above the front surface of the semiconductor substrate, a first region of the MEMS layer forming a first sealed cavity A with the first semi-open cavity on the front surface of the semiconductor substrate, and the MEMS device being arranged in the first region of the MEMS layer; a displacement sensor, which is arranged in the first sealed cavity A, and is used to detect a deformation displacement of the first region of the MEMS layer in a direction perpendicular to the MEMS layer; a cover plate, which is arranged above the MEMS layer, a second semi-open cavity being arranged on a front surface of the cover plate at a position opposite to the first region of the MEMS layer, and the second semi-open cavity forming a second sealed cavity B with the first region of the MEMS layer; and a bonding layer, which is arranged between the MEMS layer and the cover plate, and is used to bond the MEMS layer and the cover plate together, and seal the second sealed cavity B.

[0007] Further, based on the deformation displacement of the first region of the MEMS layer in the direction perpendicular to the MEMS layer detected by the displacement sensor, it is determined whether the bonding layer leaks or the semiconductor substrate leaks.

[0008] Further, the initial air pressure of the first sealed cavity A and the second sealed cavity B is consistent; when the displacement sensor detects that the first region of the MEMS layer deforms in a direction close to the semiconductor substrate, it is determined that the bonding layer leaks; and when the displacement sensor detects that the first region of the MEMS layer deforms in a direction close to the cover plate, it is determined that the semiconductor substrate leaks.

[0009] Further, the displacement sensor comprises upper and lower capacitor plates or an array of plates; and the deformation displacement of the first region of the MEMS layer in the direction perpendicular to the MEMS layer is detected by a change in capacitance of the displacement sensor.

[0010] Further, the MEMS layer is deposited above the front surface of the semiconductor substrate.

[0011] Further, the MEMS device arranged in the MEMS layer comprises a gyroscope, an accelerometer, a pressure sensor, an inertial sensor, and a biochemical sensor.

[0012] According to another aspect of the present application, the present application provides a hermetically sealed packaging structure of a cavity device, comprising: a semiconductor substrate, a first semi-open cavity and a second semi-open cavity being arranged on the front surface of the semiconductor substrate; a micro-electro-mechanical system layer, which is arranged above the front surface of the semiconductor substrate, the micro-electro-mechanical system layer is provided with a first region and a second region arranged on the surface of the micro-electro-mechanical system layer, the first region of the micro-electro-mechanical system layer and the first semi-open cavity on the front surface of the semiconductor substrate form a first sealed cavity A; the second region of the micro-electro-mechanical system layer is opposite to the second semi-open cavity; a displacement sensor, which is arranged in the first sealed cavity A, is used to detect the deformation displacement of the first region of the micro-electro-mechanical system layer in the direction perpendicular to the micro-electro-mechanical system layer; a cover plate, which is arranged above the micro-electro-mechanical system layer, is provided with a third semi-open cavity on the front surface of the cover plate opposite to the first region and the second region of the micro-electro-mechanical system layer, the third semi-open cavity, the first region of the micro-electro-mechanical system layer and the second semi-open cavity of the semiconductor substrate form a second sealed cavity B; a bonding layer, which is arranged between the micro-electro-mechanical system layer and the cover plate, is used to bond the micro-electro-mechanical system layer and the cover plate together and seal the second sealed cavity B.

[0013] Further, the first region of the micro-electro-mechanical system layer is provided with a first MEMS device; the second region of the micro-electro-mechanical system layer is provided with at least one second MEMS device.

[0014] Further, based on the deformation displacement of the first region of the micro-electro-mechanical system layer in the direction perpendicular to the micro-electro-mechanical system layer detected by the displacement sensor, it is determined whether the bonding layer leaks or the semiconductor substrate leaks.

[0015] Further, the initial air pressure of the first sealed cavity A and the second sealed cavity B is consistent; the volume of the first sealed cavity is smaller than the volume of the second sealed cavity; when the displacement sensor detects that the first region of the micro-electro-mechanical system layer deforms in the direction close to the semiconductor substrate, it is determined that the bonding layer leaks; when the displacement sensor detects that the first region of the micro-electro-mechanical system layer deforms in the direction close to the cover plate, it is determined that the semiconductor substrate leaks.

[0016] Further, the displacement sensor includes upper and lower capacitor plates or an array of plates; the deformation displacement of the first region of the micro-electro-mechanical system layer in the direction perpendicular to the micro-electro-mechanical system layer is detected by the change of the capacitance of the displacement sensor.

[0017] Further, the micro-electro-mechanical system layer is deposited above the front surface of the semiconductor substrate.

[0018] Further, the first MEMS device and the second MEMS device arranged in the micro-electro-mechanical system layer include a gyroscope, an accelerometer, a pressure sensor, an inertial sensor and a biochemical sensor.

[0019] Compared with the prior art, the air-tight packaging structure of the cavity device in the application integrates a displacement sensor, and monitors the air leakage of the wafer bonding of the sealed cavity or the air leakage of the substrate and the cavity to cause the air pressure change of the cavity, so as to realize the control and monitoring of the air tightness in the MEMS manufacturing process, provide the basis for the improvement of the performance of the MEMS, improve the yield and reduce the cost. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0021] Figure 1 It is a partial longitudinal section view of the air-tight packaging structure of the cavity device in the first embodiment of the application.

[0022] Figure 2 It is a gas leakage schematic diagram of the air-tight packaging structure of the cavity device in an embodiment of the application. Figure 1

[0023] Figure 3 It is a gas leakage schematic diagram of the air-tight packaging structure of the cavity device in an embodiment of the application. Figure 1

[0024] Figure 4 It is a partial longitudinal section view of the air-tight packaging structure of the cavity device in the second embodiment of the application.

[0025] Figure 5 It is a gas leakage schematic diagram of the air-tight packaging structure of the cavity device in an embodiment of the application. Figure 4

[0026] Figure 6 It is a gas leakage schematic diagram of the air-tight packaging structure of the cavity device in an embodiment of the application. Figure 4

DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the application will be further described in detail below with reference to the drawings and specific embodiments.

[0028] ​​​​As used in this description, and in particular, the following claims, the term "one embodiment" or "an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the disclosure. The appearances of the phrase "in one embodiment” or "in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all referring to a single, special implementation of the present disclosure. Conjunctive language such as the term "comprising” is used synonymously with conjunctive language such as the term "including.” Conjunctive language such as the term "including” or the term "comprising” is used synonymously with conjunctive language such as the term "containing” or the term "having.” Conjunctive language such as the term "containing” is used synonymously with conjunctive language such as the term "including.” The term "or” as used in a phrase such as "A or B” can be used in the equivalent sense as the term "and / or” as used in a phrase such as "A, B, or C.” The term "and / or” as used in a phrase such as "A, B, and / or C” can be used in the equivalent sense as the term "or” as used in a phrase such as "A, B, or C.” The term "a” or "an” as used in this description means "one or more,” except where it is specifically otherwise indicated. Except where otherwise indicated, all

[0029] Referring to FIG. 1, which is a partial longitudinal cross-sectional view of a hermetic package structure of a cavity device in a first embodiment of the present disclosure. Figure 1 Referring to FIG. 1, which is a partial longitudinal cross-sectional view of a hermetic package structure of a cavity device in a first embodiment of the present disclosure. Figure 1 The hermetic package structure of the cavity device includes a semiconductor substrate 110, a micro-electro-mechanical system layer (or MEMS layer) 120, a bonding layer 130, a cover plate 140, a displacement sensor 150, a first semi-open cavity (or first recess) 170, and a second semi-open cavity (or second recess) 160.

[0030] The semiconductor substrate 110 can be a substrate containing CMOS (Complementary Metal Oxide Semiconductor) integrated circuits or a simple substrate (i.e., without integrated CMOS circuits). The first semi-open cavity 170 is disposed on the front surface of the semiconductor substrate 110, and the first semi-open cavity 170 can be formed by etching or by depositing a side wall.

[0031] The micro-electro-mechanical system layer 120 is disposed above the front surface of the semiconductor substrate 110 to manufacture a MEMS device (or MEMS structure), for example, the micro-electro-mechanical system layer 120 can be deposited above the front surface of the semiconductor substrate 110. The micro-electro-mechanical system layer 120 can be deformed under appropriate conditions, and a first region (not labeled) of the micro-electro-mechanical system layer 120 forms a closed first closed cavity A with the first semi-open cavity 170 on the front surface of the semiconductor substrate 110, wherein the first region of the micro-electro-mechanical system layer 120 is provided with a MEMS device (or MEMS structure).

[0032] The displacement sensor 150 is disposed in the first closed cavity A, and the displacement sensor 150 is used to detect the deformation displacement of the first region of the micro-electro-mechanical system layer 120 in the direction perpendicular to the micro-electro-mechanical system layer 120 (or to detect the deformation displacement of the upper and lower regions of the first region of the micro-electro-mechanical system layer 120).

[0033] In one embodiment, the displacement sensor 150 includes an upper and lower capacitor plate or array of plates, such as a metal plate disposed on the surface (or bottom surface) of the first semi-open cavity 170, which forms the displacement sensor 150 with the MEMS layer 120, typically as a parallel plate capacitor, whose capacitance can change with the upward or downward movement of the MEMS layer 120. That is, by the change in capacitance of the displacement sensor 150, the deformation displacement of the first region of the MEMS layer 120 in the direction perpendicular to the MEMS layer 120 is detected.

[0034] The cover plate 140 is disposed above the MEMS layer 120, and the side surface of the cover plate 140 adjacent to the MEMS layer 120 is referred to as the front surface of the cover plate 140. The second semi-open cavity (second groove) 160 is disposed on the front surface of the cover plate 140 at a position opposite to the first region of the MEMS layer 120, and the second semi-open cavity 160 of the front surface of the cover plate 140 forms a sealed second sealed cavity B with the first region of the MEMS layer 120. In one embodiment, the cover plate 140 can be a semiconductor material or a glass material.

[0035] The bonding layer 130 is located between the MEMS layer 120 and the cover plate 140, and is used to bond the MEMS layer 120 and the cover plate 140 together and seal the second sealed cavity B. In one embodiment, the bonding method of the bonding layer 130 can be adhesive / anodic bonding, metal bonding, and hybrid metal / polymer wafer bonding.

[0036] In one embodiment, the first sealed cavity A and the second sealed cavity B have the same initial air pressure, and the first region of the MEMS layer 120, which is provided with a MEMS device, will deform in the direction perpendicular to the MEMS layer 120 (or upward and downward deformation displacement) due to the air leakage of the upper second sealed cavity B or the air leakage of the lower first sealed cavity A. Therefore, based on the deformation displacement of the first region of the MEMS layer 120 in the direction perpendicular to the MEMS layer 120 detected by the displacement sensor 150, it can be determined whether the air leakage is from the second sealed cavity B or the air leakage is from the first sealed cavity A.

[0037] Please refer to Figure 2 , which is a schematic diagram of air leakage of the air-tight packaging structure of the cavity device in one embodiment of the present application as Figure 1 , which is a schematic diagram of air leakage of the air-tight packaging structure of the cavity device in one embodiment of the present application as Figure 2In the shown embodiment, there is air leakage at the bonding layer 130 between the micro-electro-mechanical system layer 120 and the cover plate 140, which makes the air pressure of the upper second sealed cavity B greater than that of the lower first sealed cavity A. Due to the air pressure difference, the first region of the micro-electro-mechanical system layer 120 moves downward (or makes the first region of the micro-electro-mechanical system layer 120 deform and displace towards the semiconductor substrate 110), which reduces the distance between the micro-electro-mechanical system layer 120 and the bottom capacitor plate, increases the capacitance, and thus the air leakage at the bonding layer 130 can be monitored by whether the capacitance value increases. In other words, when the displacement sensor 150 detects that the first region of the micro-electro-mechanical system layer 120 deforms and displaces towards the semiconductor substrate 110, it is determined that there is air leakage at the bonding layer 130.

[0038] Please refer to Figure 3 As shown in the figure, it is a part of the longitudinal section view of the air-tight packaging structure of the cavity device according to the present application in an embodiment. Figure 1 The air release schematic diagram of the air-tight packaging structure of the cavity device is shown. In the shown embodiment, Figure 3 In the shown embodiment, the semiconductor substrate 110 has air release, which makes the air pressure of the lower first sealed cavity A greater than that of the upper second sealed cavity B. Due to the air pressure difference, the first region of the micro-electro-mechanical system layer 120 moves upward (or makes the first region of the micro-electro-mechanical system layer 120 deform and displace towards the cover plate 140), which increases the distance between the micro-electro-mechanical system layer 120 and the bottom capacitor plate, reduces the capacitance, and thus the air release of the semiconductor substrate 110 can be monitored by whether the capacitance value reduces. In other words, when the displacement sensor 150 detects that the first region of the micro-electro-mechanical system layer 120 deforms and displaces towards the cover plate 140, it is determined that the semiconductor substrate 110 has air release.

[0039] In an embodiment, the MEMS device arranged in the micro-electro-mechanical system layer 120 includes a gyroscope, an accelerometer, a pressure sensor, an inertial sensor, a biochemical sensor, etc.

[0040] In summary, the present application Figure 1 The displacement sensor 150 is integrated in the air-tight packaging structure of the cavity device, which monitors the air pressure change of the sealed cavities A and B caused by the air leakage at the bonding layer 130 or the air release of the semiconductor substrate 110, so as to realize the control and monitoring of the air-tightness in the MEMS manufacturing process, provide basis for the improvement of the MEMS performance, improve the yield, and reduce the cost.

[0041] Please refer to Figure 4 As shown in the figure, it is a part of the longitudinal section view of the air-tight packaging structure of the cavity device according to the present application in an embodiment. Figure 4The illustrated hermetic package structure of the cavity device includes a semiconductor substrate 210, a micro-electro-mechanical system layer (or MEMS layer) 220, a bonding layer 230, a cover plate 240, a displacement sensor 250, a first semi-open cavity (or first recess) 270, a second semi-open cavity (or second recess) 280, and a third semi-open cavity (or third recess) 260.

[0042] The semiconductor substrate 210 can be a substrate containing CMOS (Complementary Metal Oxide Semiconductor) integrated circuits or a simple substrate (i.e., without integrated CMOS circuits). The first semi-open cavity 270 and the second semi-open cavity 280 are arranged along the front surface of the semiconductor substrate 210, and the first semi-open cavity 270 and the second semi-open cavity 280 can be formed by etching or deposited sidewalls.

[0043] The micro-electro-mechanical system layer 220 is disposed above the front surface of the semiconductor substrate 210 to manufacture a MEMS device (or MEMS structure), for example, the micro-electro-mechanical system layer 220 can be deposited above the front surface of the semiconductor substrate 210. The micro-electro-mechanical system layer 220 can deform under appropriate conditions, and the micro-electro-mechanical system layer 220 is provided with a first region (not identified) and a second region (not identified) arranged at a distance from each other along the surface of the micro-electro-mechanical system layer 220, the first region of the micro-electro-mechanical system layer 220 forms a closed first closed cavity A with the first semi-open cavity 270 of the front surface of the semiconductor substrate 210, wherein the first region of the micro-electro-mechanical system layer 220 is provided with a first MEMS device (or first micro-electro-mechanical system structure) MEMS1; the second region of the micro-electro-mechanical system layer 220 is opposite to the second semi-open cavity 280, and the second region of the micro-electro-mechanical system layer 220 is provided with at least one second MEMS device (or second micro-electro-mechanical system structure) MEMS2.

[0044] The displacement sensor 250 is disposed in the first closed cavity A, and the displacement sensor 250 is used to detect the deformation displacement of the first region of the micro-electro-mechanical system layer 220 in the direction perpendicular to the micro-electro-mechanical system layer 220 (or to detect the deformation displacement of the first region of the micro-electro-mechanical system layer 220 up and down).

[0045] In one embodiment, the displacement sensor 250 includes an upper and lower capacitor plate or plate array, for example, a metal plate disposed on the surface (or bottom surface) of the first semi-open cavity 270, which forms the displacement sensor 250 with the micro-electro-mechanical system layer 220, typically as a parallel plate capacitor, the capacitance of which can change with the upward or downward movement of the micro-electro-mechanical system layer 220. That is, by the change of the capacitance of the displacement sensor 250, the deformation displacement of the first region of the micro-electro-mechanical system layer 220 in the direction perpendicular to the micro-electro-mechanical system layer 220 is detected.

[0046] A cover plate 240 is disposed above the microelectromechanical system (MEMS) layer 220. The side surface of the cover plate 240 adjacent to the MEMS layer 220 is referred to as the front surface of the cover plate 240. A third semi-open cavity (or third groove) 260 is provided at the position opposite to the first and second regions of the MEMS layer 220 on the front surface of the cover plate 240. The third semi-open cavity 260 on the front surface of the cover plate 240 is connected to a second semi-open cavity 280 through the second region of the MEMS layer 220. The third semi-open cavity 260 on the front surface of the cover plate 240, the first region of the MEMS layer 220, and the second semi-open cavity 280 of the semiconductor substrate 210 form a closed second semi-open cavity B. In one embodiment, the cover plate 240 may be made of a semiconductor material or a material such as glass.

[0047] The bonding layer 230 is located between the microelectromechanical system layer 220 and the cover plate 240, and is used to bond the microelectromechanical system layer 220 and the cover plate 240 together and seal the second sealed cavity B. In one embodiment, the bonding method of the bonding layer 230 can be adhesive / anodic bonding, metal bonding, and hybrid metal / polymer wafer bonding, etc.

[0048] The initial air pressure of the first sealed cavity A and the second sealed cavity B are the same, and the volume of the first sealed cavity A is smaller than the volume of the second sealed cavity B. The first region of the microelectromechanical system (MEMS) layer 220, where the first MEMS device MEMS1 is located, will undergo deformation displacement (or vertical deformation displacement) in a direction perpendicular to the MEMS layer 220 due to leakage from the bonding layer 230 or venting from the semiconductor substrate 210. Therefore, based on the deformation displacement of the first region of the MEMS layer 220 in a direction perpendicular to the MEMS layer 220 detected by the displacement sensor 250, it can be determined whether it is leakage from the bonding layer 230 or venting from the semiconductor substrate 210.

[0049] Please refer to Figure 5 As shown, this is one embodiment of the present invention. Figure 4 The diagram shows a leak in the hermetic sealing structure of a cavity device. Figure 5In the shown embodiment, there is air leakage at the bonding layer 230 between the micro-electro-mechanical system layer 220 and the cover plate 240, which causes the air pressure of the second sealed cavity B to be greater than the air pressure of the first sealed cavity A. Due to the air pressure difference, the first region of the micro-electro-mechanical system layer 220 moves downward (or causes the first region of the micro-electro-mechanical system layer 220 to deform and displace in the direction close to the semiconductor substrate 210), so that the distance between the micro-electro-mechanical system layer 220 and the bottom capacitor plate decreases, and the capacitance increases. Therefore, whether the capacitance value increases or not can be used to monitor whether there is air leakage at the bonding layer 230. In other words, when the displacement sensor 250 detects that the first region of the micro-electro-mechanical system layer 220 deforms in the direction close to the semiconductor substrate 210, it is determined that there is air leakage at the bonding layer 230.

[0050] Please refer to Figure 6 As shown in the figure, the air-tight packaging structure of the cavity device in one embodiment of the present application is Figure 4 As shown in the figure, the air-tight packaging structure of the cavity device in one embodiment of the present application is Figure 6 In the shown embodiment, the semiconductor substrate 210 has air leakage, which causes the air pressure of the first sealed cavity A to be greater than the air pressure of the second sealed cavity B. Due to the air pressure difference, the first region of the micro-electro-mechanical system layer 220 moves upward (or causes the first region of the micro-electro-mechanical system layer 220 to deform and displace in the direction close to the cover plate 240), so that the distance between the micro-electro-mechanical system layer 220 and the bottom capacitor plate increases, and the capacitance decreases. Therefore, whether the capacitance value decreases or not can be used to monitor whether the semiconductor substrate 210 has air leakage. In other words, when the displacement sensor 250 detects that the first region of the micro-electro-mechanical system layer 220 deforms in the direction close to the cover plate 240, it is determined that the semiconductor substrate 110 has air leakage.

[0051] In one embodiment, the MEMS devices MEMS1 and MEMS2 provided in the micro-electro-mechanical system layer 220 include gyroscopes, accelerometers, pressure sensors, inertial sensors, and biochemical sensors, etc.

[0052] This example provides support for the cavity vacuum monitoring of devices similar to the structure of MEMS2, and provides a basis for subsequent process manufacturing research and development.

[0053] In summary, the air-tight packaging structure of the cavity device in the present application integrates a displacement sensor, and monitors whether there is air leakage at the wafer bonding of the sealed cavity or whether the air pressure of the cavity changes due to air leakage of the substrate and the cavity, so as to realize the control and monitoring of the air tightness in the MEMS manufacturing process, thereby providing a basis for improving the performance of the MEMS, improving the yield, and reducing the cost.

[0054] In the present application, the words such as "connection", "connection", "connection", "connection" and the like represent electrical connection, and if not specifically stated, they represent direct or indirect electrical connection.

[0055] The above description is only the preferred embodiment of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiment, but any equivalent modification or change made by those skilled in the art according to the disclosure of the present application shall be included in the protection scope of the claims.

Claims

1. A hermetic package structure for a device with a cavity, characterized by, It comprises: a semiconductor substrate, the front surface of which is provided with first and second semi-open cavities arranged at a distance from each other; a micro-electro-mechanical system layer, which is arranged above the front surface of the semiconductor substrate, the micro-electro-mechanical system layer being provided with first and second regions arranged at a distance from each other along the surface thereof, the first region of the micro-electro-mechanical system layer forming a first closed cavity A with the first semi-open cavity of the front surface of the semiconductor substrate, the second region of the micro-electro-mechanical system layer being opposite the second semi-open cavity; a displacement sensor, which is arranged in the first closed cavity A, for detecting the deformation displacement of the first region of the micro-electro-mechanical system layer in a direction perpendicular to the micro-electro-mechanical system layer; a cover plate, which is arranged above the micro-electro-mechanical system layer, the front surface of the cover plate being provided with a third semi-open cavity at a position opposite the first and second regions of the micro-electro-mechanical system layer, the third semi-open cavity, the first region of the micro-electro-mechanical system layer and the second semi-open cavity of the semiconductor substrate forming a second closed cavity B; a bonding layer, which is arranged between the micro-electro-mechanical system layer and the cover plate, for bonding the micro-electro-mechanical system layer and the cover plate together and sealing the second closed cavity B, the first region of the micro-electro-mechanical system layer being provided with a first MEMS device; the second region of the micro-electro-mechanical system layer being provided with at least one second MEMS device, based on the deformation displacement of the first region of the micro-electro-mechanical system layer in a direction perpendicular to the micro-electro-mechanical system layer detected by the displacement sensor, it is determined whether the bonding layer leaks or the semiconductor substrate leaks, the volume of the first closed cavity is smaller than the volume of the second closed cavity, when the displacement sensor detects that the first region of the micro-electro-mechanical system layer deforms in a direction closer to the semiconductor substrate, it is determined that there is a leak in the bonding layer; when the displacement sensor detects that the first region of the micro-electro-mechanical system layer deforms in a direction closer to the cover plate, it is determined that there is a leak in the semiconductor substrate.

2. The hermetic packaging structure of a cavity device according to claim 1, wherein the initial air pressure of the first closed cavity A and the second closed cavity B is consistent.

3. The hermetic packaging structure of a cavity device according to claim 2, wherein the displacement sensor comprises upper and lower capacitor plates or an array of plates; the deformation displacement of the first region of the micro-electro-mechanical system layer in a direction perpendicular to the micro-electro-mechanical system layer is detected by the change in capacitance of the displacement sensor.

4. The hermetic packaging structure of a cavity device according to claim 3, wherein the micro-electro-mechanical system layer is deposited above the front surface of the semiconductor substrate.

5. The hermetic packaging structure of a cavity device according to claim 1, wherein the first and second MEMS devices arranged in the micro-electro-mechanical system layer comprise a gyroscope, an accelerometer, a pressure sensor, an inertial sensor and a biochemical sensor.

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