A wafer-level vacuum packaging method and a MEMS packaging structure with a Z-axis stop

Abstract

The present invention discloses a wafer-level vacuum packaging method with a Z-axis stop and a MEMS packaging structure manufactured by using this method, including: preparing a cover wafer; etching bonding cavities and stop structures on the cover wafer, wherein the stop structure is configured as a convex portion on the inner side of the cavity groove, and the setting position of the stop structure corresponds to the moving position of the movable structure of the MEMS device in the Z-axis direction after bonding; preparing a dielectric layer on the surface of the cover wafer; removing the dielectric layer on the surface of the stop structure; preparing bonding regions for realizing bonding in the cover wafer, and preparing getters in the cavities; bonding the cover wafer subjected to a series of treatments with a structure wafer to realize wafer-level vacuum packaging; etching lead holes for the packaged MEMS device. While realizing wafer-level vacuum packaging, the present invention also solves the overload problem in the Z-axis direction, and has the characteristics of strong process compatibility, low cost, and batch production feasibility.

Description

Technical Field

[0001] The present invention relates to the technical field of MEMS wafer-level packaging, and particularly to a wafer-level vacuum packaging method with a Z-axis stop and a MEMS device. Background Art

[0002] The packaging cost of MEMS devices has accounted for up to 95% of the total product cost at most. Currently, the lagging packaging technology and high packaging cost have severely restricted the industrial development of MEMS devices. The wafer-level packaging technology uses bonding technology to install a cover plate on the wafer with MEMS devices fabricated thereon to complete the packaging of all devices on the wafer, and then through processes such as dicing, the devices on the wafer are divided into individual devices. In most cases, the devices formed by wafer-level packaging can be directly applied without the need for individual packaging of each device, which has the advantages of low cost and batchability.

[0003] Most MEMS product devices are three-dimensional structures, and in addition to the electrical performance indicators of microelectronic products, they also have mechanical performance indicators of movable microstructures. Since the working principle often involves the movement of mechanical components, for MEMS devices with movable structures such as accelerometers and gyroscopes, in applications, they often encounter harsh environments such as shock and vibration, which may cause the movable structure to break and fail, thereby affecting the overall reliability of the device and even the system.

[0004] Therefore, in order to improve the anti-overload ability of MEMS devices, a stop structure design can be added. The stop structure is a limiting structure added to the fixed part of the MEMS device. When the MEMS device is subjected to a large overload, the displacement of its movable structure will be limited by the stop structure, thus avoiding the breakage of the movable structure due to excessive displacement. In the process of implementing the present invention, the inventor found that: the conventional stop structure processing technology is fabricated simultaneously during the processing of the MEMS movable structure. This stop structure can only limit the displacement of the movable structure in the plane. When the device is subjected to an overload perpendicular to the plane, the structure will still break. Therefore, the existing processing technology cannot solve the overload problem of the MEMS structure in the Z-axis direction. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a wafer-level vacuum packaging method with a Z-axis stop, including: preparing a cover wafer; etching bonding cavities and a stop structure on the cover wafer, wherein the stop structure is configured as a protrusion on the inner side of the cavity groove, and the setting position of the stop structure corresponds to the moving position of the movable structure of the MEMS device in the Z-axis direction after bonding; preparing a dielectric layer on the surface of the cover wafer; removing the dielectric layer on the surface of the stop structure; preparing bonding areas for realizing bonding in the cover wafer, and preparing a getter in the cavity; bonding the processed cover wafer with a structure wafer to achieve wafer-level vacuum packaging; etching lead holes for the packaged MEMS device.

[0006] Preferably, the end face of the stop structure is used to limit the moving range of the movable structure of the MEMS device in the Z-axis direction.

[0007] Preferably, the thickness of the dielectric layer is determined according to the allowable moving range of the movable structure of the MEMS device in the Z-axis direction.

[0008] Preferably, an RIE etching machine or a wet etching process is used to remove the dielectric layer on the surface of the stop structure.

[0009] Preferably, a thermal oxidation process, or a low-pressure chemical vapor deposition process, or a plasma-enhanced chemical vapor deposition process is used to prepare the dielectric layer.

[0010] Preferably, during the process of realizing wafer-level vacuum packaging, it includes: cleaning and activating the surfaces of the processed cover wafer and the structure wafer, and then performing wafer alignment; placing the aligned wafers in a vacuum bonding device and bonding them using wafer-level vacuum bonding technology; activating the getter to achieve wafer-level vacuum packaging.

[0011] Preferably, dry etching is used to etch the upper surface of the wafer after vacuum packaging, and the etching penetrates through the cover wafer to expose the metal pads, thereby forming lead holes.

[0012] Preferably, the wafer-level vacuum bonding technology includes, but is not limited to: eutectic bonding, thermocompression bonding, direct bonding, transient liquid phase bonding, and adhesive bonding.

[0013] Preferably, the material of the cover wafer is a silicon double-polished wafer.

[0014] On the other hand, the present invention also provides a MEMS packaging structure, and the MEMS packaging structure is made by using the wafer-level vacuum packaging method as described above.

[0015] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0016] The present invention discloses a wafer-level vacuum packaging method with a Z-axis stop and a MEMS packaging structure manufactured by using this method. The solution includes: 1) preparing the cover wafer material; 2) simultaneously fabricating the bonding cavity and the Z-axis stop structure inside the cavity; 3) fabricating the dielectric layer; 4) removing the dielectric layer on the surface of the stop structure; 5) fabricating the bonding area; 6) fabricating the getter; 7) aligning the wafers to be bonded and then performing bonding, and activating the getter to achieve wafer-level vacuum packaging; 8) etching the lead holes. In this way, the present invention utilizes the thickness difference of the dielectric layer between different regions to achieve the stop function of the MEMS movable structure in the Z-axis direction, thereby while achieving wafer-level vacuum packaging, also solving the overload problem in the Z-axis direction. Compared with the wafer-level vacuum packaging process without the Z-axis stop design, only two additional photolithography and dielectric etching processes are required to fabricate a high-precision Z-axis stop structure. The added processes do not increase the overall process difficulty, and it has the characteristics of strong process compatibility, low cost, and batch production feasibility.

[0017] Other features and advantages of the present invention will be described in the following specification, and part of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the specification, claims, and drawings. Description of the Drawings

[0018] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0019] Figure 1 is a step diagram of the wafer-level vacuum packaging method with a Z-axis stop according to an embodiment of the present application.

[0020] Figure 2 is a process flow diagram of the wafer-level vacuum packaging method with a Z-axis stop according to an embodiment of the present application.

[0021] Figure 3 is a cross-sectional schematic diagram of the movable structure of the wafer-level vacuum packaged MEMS device with a Z-axis stop according to an embodiment of the present application. Detailed Embodiments

[0022] The following will describe in detail the embodiments of the present invention in conjunction with the drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and the implementation process of achieving technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0023] The packaging cost of MEMS devices has accounted for up to 95% of the total product cost at most. Currently, the lagging packaging technology and high packaging cost have severely restricted the industrial development of MEMS devices. Wafer-level packaging technology uses bonding technology to install a cover plate on the wafer with MEMS devices prepared to complete the packaging of all devices on the wafer, and then through processes such as dicing, the devices on the wafer are divided into individual independent devices. In most cases, the devices formed by wafer-level packaging can be directly applied without the need for individual packaging of each device, which has the advantages of low cost and batchability.

[0024] Most MEMS product devices are three-dimensional structures. In addition to having the electrical performance indicators of microelectronic products, they also have the mechanical performance indicators of movable microstructures. Since the working principle often involves the movement of mechanical components, for MEMS devices with movable structures such as accelerometers and gyroscopes, they often encounter harsh environments such as shock and vibration during application, which may cause the movable structure to break and fail, thereby affecting the overall reliability of the device and even the system.

[0025] Therefore, in order to improve the anti-overload ability of MEMS devices, a stop structure design can be added. The stop structure is a limiting structure added to the fixed part of the MEMS device. When the MEMS device is subjected to a large overload, the displacement of its movable structure will be limited by the stop structure, thus avoiding the breakage of the movable structure due to excessive displacement. In the process of implementing the present invention, the inventor found that: the conventional processing technology of the stop structure is made simultaneously when the MEMS movable structure is processed. This stop structure can only limit the displacement of the movable structure in the plane. When the device is subjected to an overload perpendicular to the plane, it will still cause the structure to break. Therefore, the existing processing technology cannot solve the overload problem of the MEMS structure in the Z-axis direction.

[0026] In order to solve the above technical problems, an embodiment of the present invention proposes a wafer-level vacuum packaging method with a Z-axis stop. Specifically, the wafer-level vacuum packaging solution includes: a cover wafer and a structure wafer (i.e., the wafer with MEMS devices prepared). A cavity, a getter, a bonding area, and a stop structure for restricting the movement range of the movable structure of the MEMS device in the Z-axis direction are prepared on the cover wafer, and the structure wafer is prepared with the MEMS device to be packaged; the cover wafer and the structure wafer are vacuum-bonded at the wafer level through wafer vacuum bonding technology. Further, while preparing the cavity of the cover wafer, a Z-axis stop structure is also provided at the position where the movable structure needs to restrict the displacement in the Z-axis direction; then, dielectric layers are prepared on the upper and lower surfaces of the cover wafer; next, the dielectric layer on the surface of the Z-axis stop structure is removed, so as to use the thickness difference of the dielectric layers between different regions to realize the movement restriction of the MEMS movable structure in the Z-axis direction; finally, the wafer-level vacuum packaging of the MEMS structure is realized by using wafer vacuum bonding technology.

[0027] In this way, the wafer-level vacuum packaging method provided by the embodiments of the present invention can effectively limit the movement range of the MEMS movable structure in the Z-axis direction, thereby solving the overload problem in this direction.

[0028] In addition, for the MEMS device with a movable structure fabricated by using the wafer-level vacuum packaging method provided by the embodiments of the present invention, especially the MEMS device whose moving direction is along the Z-axis, the three-dimensional anti-overload ability of such devices can be greatly improved, and the device reliability can be enhanced.

[0029] Figure 3 It is a schematic cross-sectional view of the movable structure of the wafer-level vacuum packaged MEMS device with a Z-axis stop according to the embodiments of the present application. Figure 3 It shows the cross-sectional view of the package of the movable structure of the MEMS device fabricated by using the (hereinafter described) wafer-level vacuum packaging method according to the embodiments of the present invention. As Figure 3 shown, the package structure of the MEMS device includes, but is not limited to: a cover wafer 1 and a structure wafer for fabricating the MEMS device to be packaged (see the dashed box in Figure 3 , not numbered). The cover wafer 1 at least has: a cavity 2 provided on the lower surface of the cover wafer 1, a dielectric layer 3, a wafer bonding area 4 in the cavity 2, a getter 5 in the cavity 2, a stop structure 6 in the cavity 2, and a metal pad 8. In addition, on the structure wafer of the MEMS device to be packaged, there is a movable structure 7 of the MEMS device.

[0030] Figure 1 It is a step diagram of the wafer-level vacuum packaging method with a Z-axis stop according to the embodiments of the present application. Figure 2 It is a process flow diagram of the wafer-level vacuum packaging method with a Z-axis stop according to the embodiments of the present application. The implementation process of the wafer-level vacuum packaging method described in the embodiments of the present invention will be described below in conjunction with Figure 1 and Figure 2 For the implementation process of the wafer-level vacuum packaging method described in the embodiments of the present invention will be described below in conjunction with

[0031] Step S110: Prepare the cover wafer. In step S110, referring to Figure 2 , it is necessary to select the material of the cover wafer 1 corresponding to the packaging requirements of the current MEMS device to be packaged according to the specifications, types, and other requirements of the MEMS device to be packaged. Specifically, in the embodiments of the present invention, the material of the cover wafer 1 is a silicon double-polished wafer, and the silicon wafer material is further selected according to the device packaging requirements.

[0032] It should be noted that the embodiments of the present invention do not specifically limit the thickness, size, doping method, etc. of the cover wafer material, and those skilled in the art can configure them according to actual packaging requirements.

[0033] After the preparation of the cover wafer 1 is completed, step S120 is entered. In step S120, a cavity for bonding and a stop structure are etched on the configured cover wafer 1. As Figure 2 shown, in step S120, while preparing the cavity on the cover wafer 1, a Z-axis stop structure 6 is provided at the position where the movable structure in the MEMS device to be packaged needs to limit the displacement in the Z-axis direction. Further, an upper cavity is prepared on the lower surface of the cover wafer 1 (refer to Figure 3 ), and a corresponding protrusion is provided inside the cavity groove, so that the stop structure 6 in the cavity is formed by the protrusion. Among them, the stop structure 6 is configured as a protrusion inside the cavity groove, and the setting position of the stop structure 6 corresponds to the (Z-axis) movable position of the movable structure of the MEMS device in the Z-axis direction after wafer bonding is completed.

[0034] Furthermore, the end face of the stop structure 6 is used to limit the movable range of the movable structure of the MEMS device in the Z-axis direction. At the same time, the side face of the stop structure 6 is a plane. In addition, in the embodiment of the present invention, the cross-sectional shape of the stop structure 6 is selected from any one of a circle, a rectangle, a square, and the like.

[0035] In the process of simultaneously preparing the bonding cavity and the Z-axis stop structure, first, a photoresist is used as a mask, and a cavity for realizing wafer bonding and a Z-axis stop structure are formed on the lower surface of the cover wafer material through exposure and development; then, an etching machine with reactive ion etching (RIE) ability is used to etch the lower surface of the cover wafer, and the etching depth is determined according to the packaging requirements of the MEMS device to be packaged. In this way, the above step S120 is completed, and step S130 is entered.

[0036] Step S130 prepares a dielectric layer on the surface of the cover wafer 1. That is to say, in step S130, dielectric layers 3 for realizing insulation and Z-axis stop functions need to be prepared on the upper and lower surfaces of the cover wafer 1 on which the cavity and the stop structure have been simultaneously prepared. In the actual application process, since the embodiment of the present invention uses the thickness difference of the dielectric layer between different regions (bonding region and stop structure region) to realize the restriction of the movable range of the movable structure of the MEMS device in the Z-axis direction. Therefore, the dielectric layer 3 can not only realize insulation but also has a Z-axis stop function. Therefore, in the embodiment of the present invention, the thickness of the dielectric layer 3 is determined according to the allowable movable range of the movable structure of the MEMS device to be packaged in the Z-axis direction.

[0037] Further, in the embodiments of the present invention, the dielectric layer 3 can be prepared by a thermal oxidation process, or a low pressure chemical vapor deposition (LPCVD) process, or a plasma enhanced chemical vapor deposition (PECVD) process.

[0038] It should be noted that the embodiments of the present invention do not specifically limit the material of the dielectric layer 3. Those skilled in the art can select according to the actual situation as long as it can achieve insulation, avoid leakage during subsequent wafer bonding, and its thickness can meet the stop function. For example: the material of the dielectric layer 3 can be an insulating material such as silicon oxide or silicon nitride.

[0039] In this way, after the preparation of the dielectric layer 3 is completed, it enters step S140. In step S140, the dielectric layer 3 on the surface of the stop structure 6 is removed, so that the stop function of the movable structure of the MEMS device in the Z-axis direction can be realized by using the thickness difference of the dielectric layer between different regions. Since there is no dielectric layer on the surface of the stop structure, the actual movable displacement range of the movable structure 7 of the MEMS device in the Z-axis direction is the thickness of the dielectric layer. Therefore, the present invention can limit the movement range of the movable structure of the MEMS device in the Z direction by the thickness of different dielectrics.

[0040] In step S140, an RIE etcher or a wet etching process is used to remove the dielectric layer on the surface of the stop structure. Specifically, first, a photoresist is used as a mask, and the photoresist on the surface of the Z-axis stop structure 6 is removed by exposure and development; then, an RIE etcher or a wet etching technique is used to remove the dielectric layer 3 on the surface of the Z-axis stop structure 6, so as to realize the stop function of the MEMS movable structure in the Z-axis direction by using the thickness difference of the dielectric layer between different regions. At this time, step S140 ends and enters step S150.

[0041] Step S150 prepares a bonding region 4 for bonding in the cover wafer 1. (Refer to Figure 3 ) In step S150, it is necessary to prepare a bonding region 4 in the region of the cover wafer 1 for wafer bonding and a bonding region 4 in the region of the structure wafer for bonding. Specifically, first, the preparation process of the bonding region 4 needs to be adapted to the type of bonding technology selected by the subsequent wafer bonding technology.

[0042] For example, when the metal eutectic bonding technology is selected in the subsequent wafer bonding process, first, a physical vapor deposition (PVD) process or a metalorganic chemical vapor deposition (MOCVD) process is used to deposit the metal layer required for wafer bonding in the regions of the cover wafer and the structural wafer used for bonding. Then, photoresist is used as a mask, and the photoresist on the surface of the non-bonding region is removed through exposure and development. Finally, a wet etching technology is used to remove the metal in the non-bonding region to realize the preparation of the bonding region 4.

[0043] Step S160 prepares a getter 5 in the cavity of the cover wafer 1 for realizing vacuum packaging of the MEMS device. That is to say, in step S160, for the MEMS device that needs to be vacuum packaged, a getter 5 is prepared in the cavity 2 of the cover wafer 1.

[0044] After the preparation of the bonding region 4 and the getter 5 is completed, it enters step S170. Step S170 bonds the cover wafer 1 that has undergone a series of processes with the structural wafer to realize wafer-level vacuum packaging of the MEMS device. In step S170, after aligning the wafers to be bonded (cover wafer and structural wafer) that have undergone a series of processes from step S110 to step S160, they are placed in a vacuum bonding device, and the wafers are bonded together. After activating the getter, wafer-level vacuum packaging is realized.

[0045] Specifically, first, the surfaces of the cover wafer and the structural wafer that have undergone a series of processes are cleaned, activated, etc. Then, the cover wafer and the structural wafer are wafer-aligned so that the patterns on the cover wafer and the structural wafer are accurately aligned together. Next, the aligned wafers are placed in a vacuum bonding device, and the two wafers are bonded together using wafer-level vacuum bonding technology. The getter 5 is activated to realize wafer-level vacuum packaging. Among them, in the embodiment of the present invention, the wafer-level vacuum bonding technology includes, but is not limited to: eutectic bonding, thermocompression bonding, direct bonding, transient liquid phase bonding, and adhesive bonding. Those skilled in the art can choose one of them to realize wafer-level vacuum packaging.

[0046] In this way, after the wafer-level vacuum packaging is completed, step S170 ends and enters step S180.

[0047] Step S180 etches lead holes for the packaged MEMS device to form lead holes. In step S180, dry etching (for example, an etching machine with deep reactive ion etching ability) is used to etch the upper surface of the wafer that has completed vacuum packaging, and the etching penetrates through the cover wafer 1 to expose the pad structure, thereby forming lead holes.

[0048] Specifically, first, a double-sided lithography process is adopted. Using photoresist as a mask, via exposure and development, a lead hole pattern is formed on the upper surface of the cover wafer material. Then, an etcher with Deep Reactive Ion Etching (DRIE) capability is used to etch the upper surface of the wafer after vacuum packaging is completed, etching through the cover wafer to expose the metal pads, thereby forming lead holes.

[0049] Thus, through the wafer-level vacuum packaging method described in steps S110 to S180 above, the embodiments of the present invention can accurately implement the design of the stop structure in the Z-axis direction. For MEMS devices with movable structures, especially MEMS devices whose movement direction is along the Z-axis, the three-dimensional anti-overload performance of the devices can be greatly improved, enhancing the device reliability.

[0050] The present invention discloses a wafer-level vacuum packaging method with a Z-axis stop, and a MEMS packaging structure manufactured by the foregoing method. The solution includes: 1) Preparation of cover wafer material; 2) Simultaneously preparing a bonding cavity and a Z-axis stop structure inside the cavity; 3) Preparation of a dielectric layer; 4) Removing the dielectric layer on the surface of the stop structure; 5) Preparation of a bonding area; 6) Preparation of a getter; 7) Aligning the wafers to be bonded and then performing bonding, and activating the getter to achieve wafer-level vacuum packaging; 8) Etching of lead holes. In this way, the present invention utilizes the thickness difference of the dielectric layer between different regions to achieve the stop function of the MEMS movable structure in the Z-axis direction. Thus, while realizing wafer-level vacuum packaging, the overload problem in the Z-axis direction is also solved. Compared with the wafer-level vacuum packaging process without a Z-axis stop design, only two additional photolithography and dielectric etching processes are required to process a high-precision Z-axis stop structure. The added processes do not increase the overall process difficulty, and it has the characteristics of strong process compatibility, low cost, and batch production feasibility.

[0051] In addition, since the present invention uses the thickness difference of the dielectric layer in different regions to achieve the Z-axis stop function, the dielectric layer has high thickness uniformity and thickness control accuracy (≤±2%), and the size design of the Z-axis stop can be accurately implemented. Thus, for MEMS devices with movable structures, especially MEMS devices whose movement direction is along the Z-axis, this design can greatly improve the three-dimensional anti-overload performance of the devices, enhancing the device reliability.

[0052] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those familiar with the technology within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0053] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are for the purpose of describing specific embodiments only and do not imply limitation.

[0054] The phrase "one embodiment" or "an embodiment" mentioned in the specification means that the specific features, structures or characteristics described in connection with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "an embodiment" appearing throughout the specification do not necessarily all refer to the same embodiment.

[0055] Although the embodiments disclosed in the present invention are as above, the content described above is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and variations in the form of implementation and details without departing from the spirit and scope disclosed by the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A wafer-level vacuum packaging method with a Z-axis stop, comprising: Preparing a cover wafer; Etching bonding cavities and stop structures on the cover wafer, wherein the stop structure is configured as a protrusion on the bottom of the cavity groove inside the cavity groove, and the setting position of the stop structure corresponds to the moving position of the movable structure of the MEMS device in the Z-axis direction after bonding; Preparing a dielectric layer on the surface of the cover wafer, wherein the thickness of the dielectric layer is determined according to the allowable movement range of the movable structure of the MEMS device in the Z-axis direction; Removing the dielectric layer on the end surface of the stop structure to achieve the Z-axis stop function only by using the thickness difference of the dielectric layer in different regions; Preparing bonding areas for bonding in the cover wafer and preparing getters in the cavity; Bonding the cover wafer that has undergone a series of treatments with the structure wafer to achieve wafer-level vacuum packaging; Etching lead holes for the packaged MEMS device.

2. The wafer-level vacuum packaging method according to claim 1, wherein The end surface of the stop structure is used to limit the movement range of the movable structure of the MEMS device in the Z-axis direction.

3. The wafer-level vacuum encapsulation method according to claim 1 or 2, wherein Using an RIE etching machine or a wet etching process to remove the dielectric layer on the surface of the stop structure.

4. The wafer-level vacuum packaging method according to claim 1, wherein Adopting a thermal oxidation process, or a low-pressure chemical vapor deposition process, or a plasma-enhanced chemical vapor deposition process to prepare the dielectric layer.

5. The wafer-level vacuum packaging method according to claim 1, wherein During the process of achieving wafer-level vacuum packaging, it includes: Cleaning and activating the surfaces of the cover wafer that has undergone a series of treatments and the structure wafer, and then performing wafer alignment; Placing the aligned wafers in a vacuum bonding device and bonding them using wafer-level vacuum bonding technology; Activating the getter to achieve wafer-level vacuum packaging.

6. The wafer-level vacuum packaging method according to claim 1, characterized in that, Using dry etching on the upper surface of the wafer after vacuum packaging to etch through the cover wafer to expose the metal pads, thereby forming lead holes.

7. The wafer-level vacuum packaging method according to claim 1 or 6, characterized in that The wafer-level vacuum bonding technology includes, but is not limited to: eutectic bonding, thermocompression bonding, direct bonding, transient liquid-phase bonding, and adhesive bonding.

8. The wafer-level vacuum packaging method according to claim 1, characterized in that, The material of the cover wafer is a silicon double-polished wafer.

9. A MEMS packaging structure, characterized in that, The MEMS packaging structure is made by using the wafer-level vacuum packaging method according to any one of claims 1 to 8.

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