A Wafer-Level Packaging Method and Packaging Structure for MEMS Devices

Abstract

The present invention discloses a wafer-level packaging method and a packaging structure for MEMS devices, belonging to the field of semiconductor technology. The wafer-level packaging method for MEMS devices includes: opening a slot along the outer periphery of the first preset position at the first end of the cover plate substrate; installing a carrier plate at the first end to connect the cover plate substrate at the first preset position to the carrier plate; removing the material at the second end of the cover plate substrate opposite to the first end to make the slot a through slot; setting a first glue layer at the second preset position at the second end of the cover plate substrate; the MEMS wafer includes a device structure and metal pads arranged around the device structure, the cover plate substrate corresponding to the first preset position and the first glue layer package the device structure, and the metal pads are arranged opposite to the through slot; removing the carrier plate. The wafer-level packaging structure for MEMS devices is made by the above-mentioned wafer-level packaging method for MEMS devices. The wafer-level packaging method and packaging structure for MEMS devices of the present invention simplify the process, have high packaging efficiency, and small structural dimensions.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a wafer-level packaging method and a packaging structure for MEMS devices. Background Art

[0002] Micro-Electro-Mechanical Systems (MEMS) involve multiple disciplines and technologies such as electronics, mechanics, and materials, and are widely used in products such as micro pressure sensors, acceleration sensors, and microphones, with broad application prospects. In practical applications, it is required to further reduce the size and cost of the MEMS device packaging structure, while improving the integration and performance. In the wafer-level packaging method and packaging structure of MEMS devices, in traditional processes, planar substrate packaging is mainly used, and through the wire bonding process, the packaging efficiency is low and the packaging volume is large; in the prior art, the wire bonding process is replaced by connecting through a conductive member to an electrode, which reduces the packaging size to a certain extent, but cannot reduce the packaging thickness, and the process is complex and the production cost is high, reducing the market competitiveness of the product. Summary of the Invention

[0003] An object of the present invention is to provide a wafer-level packaging method for MEMS devices, which simplifies the packaging process, has high packaging efficiency, and reduces the size of the packaging structure.

[0004] To achieve this purpose, the present invention adopts the following technical solutions:

[0005] A wafer-level packaging method for MEMS devices includes:

[0006] Opening a slot along the outer periphery of the first preset position at the first end of the cover substrate;

[0007] Installing a carrier plate at the first end of the cover substrate, and connecting the cover substrate at the first preset position to the carrier plate;

[0008] Removing the material at the second end of the cover substrate opposite to the first end to make the slot a through slot;

[0009] Setting a first glue layer at the second preset position at the second end of the cover substrate;

[0010] The MEMS wafer includes a device structure and metal pads arranged around the device structure. The cover substrate and the first glue layer corresponding to the first preset position package the device structure, and the metal pads are arranged opposite to the through slot;

[0011] Removing the carrier plate to form a wafer-level packaging structure for MEMS devices.

[0012] Optionally, after removing the carrier plate, it further includes soldering on the metal pads.

[0013] Optionally, before forming the slot along the first preset position at the first end of the cover substrate, it further includes disposing a second adhesive layer on the cover substrate and removing the second adhesive layer at the first preset position;

[0014] After forming the slot along the first preset position at the first end of the cover substrate, it further includes removing the remaining second adhesive layer.

[0015] Optionally, before mounting the carrier plate at the first end of the cover substrate, it further includes disposing a third adhesive layer at the first end of the cover substrate, and bonding the cover substrate and the carrier plate through the third adhesive layer;

[0016] After removing the carrier plate, it further includes removing the third adhesive layer.

[0017] Optionally, the MEMS device wafer-level packaging method further includes:

[0018] Pressing a dry film at the second end of the cover substrate and removing the dry film outside the second preset position to form the first adhesive layer at the second preset position.

[0019] Optionally, the cover substrate and the MEMS wafer are aligned by infrared rays so that the cover substrate corresponding to the first preset position and the device structure, and the through groove and the metal pad are respectively oppositely disposed.

[0020] Another object of the present invention is to provide a MEMS device wafer-level packaging structure, which simplifies the packaging process, has high packaging efficiency, and reduces the size of the packaging structure.

[0021] To achieve this purpose, the present invention adopts the following technical solutions:

[0022] A MEMS device wafer-level packaging structure made by the above MEMS device wafer-level packaging method, includes:

[0023] A MEMS wafer, including a device structure and metal pads disposed around the device structure;

[0024] A cover substrate, including at least two sub-boards, each of the sub-boards is respectively disposed corresponding to the device structure, the metal pads are disposed around each of the sub-boards, and the cover substrate is connected to the MEMS wafer;

[0025] A dry film, connected between the cover substrate and the MEMS wafer, and the cover substrate and the dry film package the device structure.

[0026] Optionally, solder balls are welded on the metal pads.

[0027] Optionally, a protective layer is provided between the metal pad and the solder ball.

[0028] Optionally, the height of the solder ball is not less than 100 um.

[0029] Advantages of the present invention:

[0030] A wafer-level packaging method for MEMS devices provided by the present invention. During the manufacturing process, the manufacturing of the cover substrate, the manufacturing of the first adhesive layer, and the manufacturing of the MEMS wafer are all wafer-level packaging. After the packaging is completed, a wafer-level packaging structure for MEMS devices is formed. Through the wafer-level packaging method, the process is simple and the reliability is high; multiple MEMS device packaging structures can be packaged at one time, with high packaging efficiency, reduced cost, mature packaging technology, and low requirements for packaging materials and equipment; the wafer-level packaging structure of the MEMS device is the same size as the MEMS wafer, and the thickness increase is small, meeting the requirements of the ultra-thin packaging process; the cover substrate is manufactured separately and then bonded to the MEMS wafer, reducing the risk of low yield or scrapping of the MEMS wafer and simplifying the packaging process.

[0031] A wafer-level packaging structure for MEMS devices provided by the present invention. The connection with the external structure through the metal pad replaces the lead connection, with a simple process and high reliability; the dry film structure is thinner, and the dry film bonds the cover substrate and the MEMS wafer, which can reduce the thickness of the packaging structure and meet the production process requirements of the ultra-thin packaging structure. Specifically, the size of the packaged MEMS device packaging structure is greatly reduced. The packaging structure of the MEMS device packaging structure is the same size as the MEMS wafer, and the structure of the cover substrate is thinner, resulting in a small increase in the thickness of the packaging structure, generally with a small thickness increase, meeting the requirements of the ultra-thin packaging process. The dry film replaces the traditionally used photoresist, preventing the photoresist from flowing onto the peripheral surface of the cover substrate and affecting the product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of the cover substrate provided with a second adhesive layer in the specific embodiment of the present invention;

[0033] Figure 2 It is a schematic structural diagram of the cover substrate removing the second adhesive layer at the first preset position in the specific embodiment of the present invention;

[0034] Figure 3 It is a schematic structural diagram of the cover substrate grooving at the first preset position in the specific embodiment of the present invention;

[0035] Figure 4 It is a schematic structural diagram of the cover substrate provided with a third adhesive layer at the first end in the specific embodiment of the present invention;

[0036] Figure 5It is a schematic structural diagram of a carrier board arranged on a cover plate substrate provided by a specific embodiment of the present invention;

[0037] Figure 6 It is a schematic structural diagram of the cover plate substrate after removing materials at the second end provided by a specific embodiment of the present invention;

[0038] Figure 7 It is a schematic structural diagram of a dry film arranged at the second end of the cover plate substrate provided by a specific embodiment of the present invention;

[0039] Figure 8 It is a schematic structural diagram of a first adhesive layer formed at the second end of the cover plate substrate provided by a specific embodiment of the present invention;

[0040] Figure 9 It is a schematic structural diagram of the connection between the cover plate substrate and the MEMS wafer provided by a specific embodiment of the present invention;

[0041] Figure 10 It is a schematic structural diagram of the connection between the cover plate substrate and the MEMS wafer after removing the carrier board and the third adhesive layer provided by a specific embodiment of the present invention;

[0042] Figure 11 It is a schematic structural diagram of a protective layer arranged on the metal pad provided by a specific embodiment of the present invention;

[0043] Figure 12 It is a schematic structural diagram of the wafer-level packaging structure of the MEMS device provided by a specific embodiment of the present invention;

[0044] Figure 13 It is a schematic structural diagram of the packaging structure of a single MEMS device provided by a specific embodiment of the present invention;

[0045] Figure 14 It is a flowchart of the wafer-level packaging method of the MEMS device provided by a specific embodiment of the present invention.

[0046] In the figure:

[0047] 101 - Cover plate substrate; 1011 - Through groove; 1012 - Groove; 102 - Second adhesive layer; 103 - UV release protective film; 104 - Bonding adhesive; 105 - Carrier board;

[0048] 201 - First adhesive layer;

[0049] 301 - MEMS wafer; 302 - Metal pad; 303 - Protective layer; 304 - Solder ball. Specific embodiment

[0050] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0051] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0052] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "above", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "below", and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0053] This embodiment provides a wafer-level packaging method for a MEMS device, as Figures 1-14 shown, including:

[0054] S1: Open a through groove 1011 on the cover substrate 101 along a first preset position; specifically, it includes the following steps:

[0055] S110: Open a slot 1012 along the outer periphery of the first preset position at the first end of the cover substrate 101;

[0056] S120: Install a carrier plate 105 at the first end of the cover substrate 101, and the cover substrate 101 at the first preset position is connected to the carrier plate 105;

[0057] S130: Remove the material at the second end of the cover substrate 101 opposite to the first end, that is, remove the bottom structure of the slot 1012, so that the slot 1012 becomes a through groove 1011;

[0058] S2: Set a first adhesive layer 201 at a second preset position at the second end of the cover plate substrate 101;

[0059] S3: The MEMS wafer 301 includes a device structure and metal pads 302 arranged around the device structure. The cover plate substrate 101 and the first adhesive layer 201 corresponding to the first preset position encapsulate the device structure, and the metal pads 302 are arranged opposite to the through grooves 1011;

[0060] S4: Remove the carrier plate 105 to form a MEMS device wafer-level packaging structure.

[0061] Among them, the first preset position is the position corresponding to the device structure on the MEMS wafer 301. A through groove 1011 is opened along the outer periphery of the first preset position so that the metal pads 302 are arranged opposite to the through grooves 1011, and the metal pads 302 are exposed on the packaging structure. After the through groove 1011 is opened along the outer periphery of the first preset position, the cover plate substrate 101 corresponding to the first preset position is divided into at least two independent sub-boards by the through groove 1011. To facilitate the subsequent installation of each sub-board on the MEMS wafer 301, each sub-board is installed on the carrier plate 105, and each sub-board is connected by the carrier plate 105 to facilitate the one-time installation of each sub-board on the MEMS wafer 301 and improve the assembly efficiency; the second preset position is the connection position between the MEMS wafer 301 and the cover plate substrate 101, and the second preset position is arranged around the device structure.

[0062] In the above manufacturing process, the manufacturing of the cover plate substrate 101, the manufacturing of the first adhesive layer 201, and the manufacturing of the MEMS wafer 301 are all wafer-level packaging. After packaging, a MEMS device wafer-level packaging structure is formed. Specifically, the MEMS device wafer-level packaging structure can be cut into single MEMS device packaging structures according to requirements; multiple MEMS device packaging structures can be packaged at one time, with high packaging efficiency, reduced cost, mature packaging technology, and low requirements for packaging materials and equipment; the size of the packaged MEMS device wafer packaging structure is greatly reduced, the size of the MEMS device wafer packaging structure is the same as that of the MEMS wafer 301, the structure of the cover plate substrate 101 is relatively thin, and the increase in the thickness of the packaging structure is small, generally the thickness is increased by 60 - 100um, meeting the requirements of the ultra-thin packaging process; the cover plate substrate 101 is manufactured separately and then bonded to the MEMS wafer 301, reducing the risk of low yield or scrapping of the MEMS wafer 301 and simplifying the packaging process.

[0063] Connecting to an external structure through the metal pad 302 to replace wire bonding, the process is simple and highly reliable. The wafer-level packaging structure of the single MEMS device packaging structure obtained can be directly installed on the system board through SMT (Surface Mounted Technology), replacing the traditional wire bonding method and facilitating subsequent installation and use. Optionally, after removing the carrier plate 105, it further includes soldering on the metal pad 302, and the metal pad 302 is connected to the external structure through soldering, which is convenient and reliable for connection.

[0064] Optionally, the cover substrate 101 can be a silicon wafer, and the silicon wafer is processed with through-silicon vias (TSV) by dry etching; optionally, the cover substrate 101 can also be a glass plate, and the glass plate can achieve through-glass vias (TGV) through laser drilling and wet etching. Optionally, the thickness of the cover substrate 101 is set between 0.45 - 0.75 mm, and the shape of the cover substrate 101 can be a wafer, a square piece or other shapes.

[0065] Successively open a slot 1012 at the first end of the cover substrate 101, install the carrier plate 105 at the first end of the cover substrate 101, and finally remove the material from the end face of the second end of the cover substrate 101. Removing the material after installing the carrier plate 105 aims to protect the cover substrate 101 during the processing and prevent it from cracking. Optionally, the carrier plate 105 is a glass plate, and the thickness of the glass plate can be set to 0.1 mm - 1.1 mm, and generally, a thickness of 0.4 mm is selected.

[0066] Specifically, when removing the material from the second end of the cover substrate 101, the material at the second end of the cover substrate 101 can be ground away by mechanical grinding to make the slot 1012 a through slot 1011, preparing for connecting the MEMS wafer 301 in the subsequent process. The thickness of the entire cover substrate 101 can be 30 um - 500 um, and the general thickness is 100 um.

[0067] Optionally, as Figures 1-3 and Figure 10 shown, before S110, it further includes:

[0068] S111: Set a second adhesive layer 102 on the cover substrate 101 and remove the second adhesive layer 102 at a first preset position. Then, etch a slot 1012 with a required depth at the position where the second adhesive layer 102 is removed and the unprotected area of the second adhesive layer 102. By setting the second adhesive layer 102, the position of the through slot 1011 of the slot 1012 is set to make the position of the through slot 1011 more accurate;

[0069] After S110, it further includes:

[0070] S112: Remove the remaining second adhesive layer 102 to prevent the second adhesive layer 102 from affecting subsequent processing and to avoid affecting the thickness of the encapsulation structure. Optionally, the second adhesive layer 102 is a photoresist. Specifically, a layer of photoresist is coated on the cover substrate 101. The photoresist is a positive photosensitive material, and the required pattern is obtained through coating, exposure, and development. After that, it is generally removed by acetone brushing or other methods.

[0071] Optionally, as Figure 4 shown, before S120, it further includes:

[0072] S121: Set a third adhesive layer at the first end of the cover substrate 101. The cover substrate 101 and the carrier plate 105 are bonded through the third adhesive layer. One function of the third adhesive layer is to protect the through groove 1011 to prevent colloid from adhering to the hole or other structural damage to the through groove 1011 during subsequent manufacturing. Another function of the third adhesive layer is for bonding the cover substrate 101 and the glass carrier. Specifically, the third adhesive layer may include a UV anti-sticking protective film 103 and a bonding adhesive 104. In this embodiment, a layer of UV anti-sticking protective film 103 is pasted at the first end where the through groove 1011 has been etched. The UV anti-sticking protective film 103 is used to protect the through groove 1011; then a layer of temporary bonding adhesive 104 solution or a bonding double-sided film is coated on the UV anti-sticking protective film 103 for bonding the cover substrate 101 and the glass carrier.

[0073] After removing the carrier plate 105, it further includes:

[0074] S122: Remove the third adhesive layer to prevent the third adhesive layer from affecting subsequent processing and to prevent the third adhesive layer from affecting the thickness of the encapsulation structure.

[0075] The traditional first adhesive layer 201 is made by coating a layer of negative photoresist and then forming the first adhesive layer 201 through exposure and development. However, there are etched holes on the processing surface of the cover substrate 101, and the photoresist cannot be directly coated. To solve the above problem, specifically, as Figure 7 and Figure 8 shown, S2 includes:

[0076] S210: Press a dry film at the second end of the cover substrate 101 and remove the dry film outside the second preset position to form the first adhesive layer 201 at the second preset position; by pressing the dry film on the cover substrate 101, it prevents the photoresist from flowing into the through groove 1011, and the first adhesive layer 201 at the second preset position is formed through exposure and development. The manufacturing method of bonding the dry film to the cover substrate 101 can produce an ultra-thin cover substrate 101, meeting the requirements of the ultra-thin production process.

[0077] As Figure 9As shown, optionally, the cover substrate 101 and the MEMS wafer 301 are aligned by infrared rays so that the cover substrate 101 corresponding to the first preset position, the device structure, and the through groove 1011 and the metal pad 302 are respectively disposed opposite to each other. The alignment effect is good, the speed is fast, and the operation is convenient. Then, the cover substrate 101 and the MEMS wafer 301 are pressed together. Then, as Figure 10 shown, referring to the above steps S140 and S121, the third adhesive layer and the carrier plate 105 are removed, which will not be repeated.

[0078] As Figure 12 shown, before cutting the whole MEMS device package structure into single MEMS device package structures, solder balls 304 are welded on the metal pads 302, and the MEMS device package structure is connected to an external structure through the solder balls 304; preferably, the height of the solder balls 304 > 100 um; optionally, before welding the solder balls 304 on the metal pads 302, a protective layer 303 is plated on the surface of the metal pads 302 of the MEMS wafer 301 by electroless plating. Preferably, the electroless plating material can be Ni / Au or Ni / Pd, etc. The purpose is to prevent the metal pads 302 from oxidation and increase the bonding force between the metal pads 302 and the solder balls 304, so that the solder ball 304 structure is stable.

[0079] Specifically, as Figure 12 and Figure 13 shown, the MEMS device wafer-level package structure can be changed into single MEMS device package structures by means of mechanical cutting or laser cutting, etc.

[0080] This embodiment also provides a MEMS device wafer-level package structure, which is made by the above-mentioned MEMS device wafer-level package method. It includes a MEMS wafer 301, a cover substrate 101, and a dry film. Specifically, as Figure 12 shown, the MEMS wafer 301 includes a device structure and metal pads 302 arranged around the device structure; the cover substrate 101 is provided with through grooves 1011 disposed opposite to the metal pads 302. The cover substrate 101 includes at least two sub-boards, and each sub-board is respectively disposed corresponding to the device structure. The metal pads 302 are arranged around each sub-board. The cover substrate 101 is connected to the MEMS wafer 301; the dry film is connected between the cover substrate 101 and the MEMS wafer 301, and the cover substrate 101 and the dry film encapsulate the device structure.

[0081] Connecting to an external structure through the metal pad 302 instead of wire bonding simplifies the process and offers high reliability. The dry film structure is relatively thin. The dry film bonds the cover plate substrate 101 and the MEMS wafer 301, which can reduce the thickness of the package structure and meet the production process requirements of an ultra-thin package structure. Specifically, the size of the package structure of the packaged MEMS device is greatly reduced. The package structure of the MEMS device package is the same size as the MEMS wafer 301. The structure of the cover plate substrate 101 is relatively thin, resulting in a small increase in the thickness of the package structure. Generally, the thickness increase is small, usually increased by 60 - 100um, meeting the requirements of the ultra-thin packaging process. The dry film replaces the conventionally used photoresist, preventing the photoresist from flowing onto the peripheral surface of the cover plate substrate 101 and affecting product quality.

[0082] The wafer-level package structure of the MEMS device provided in this embodiment can be fabricated using the above-mentioned manufacturing method. This is convenient during the manufacturing process, that is, the fabrication of the cover plate substrate 101, the fabrication of the first adhesive layer 201, and the fabrication of the MEMS wafer 301 are all wafer-level packages. After the package is completed, a wafer-level package structure of the MEMS device is formed, and then the wafer-level package structure of the MEMS device is cut into individual MEMS device package structures; multiple MEMS device package structures can be packaged at one time, with high packaging efficiency, reduced costs, mature packaging technology, and low requirements for packaging materials and equipment; the cover plate substrate 101 is fabricated separately and then bonded to the MEMS wafer 301, reducing the risk of low yield or scrapping of the MEMS wafer 301 and simplifying the packaging process. The wafer-level package structure of an individual MEMS device package structure can be directly installed on the system board through SMT, replacing the traditional wire bonding method, which is convenient for subsequent installation and use.

[0083] Optionally, a sealant is provided on the MEMS wafer 301. The sealant is connected to the dry film, improving the connection strength between the cover plate substrate 101 and the MEMS wafer 301 and enhancing the structural reliability.

[0084] Optionally, solder balls 304 are welded onto the metal pads 302, enabling the MEMS device package structure to be connected to an external structure through the solder balls 304.

[0085] Optionally, a protective layer 303 is provided between the metal pads 302 and the solder balls 304, aiming to prevent oxidation of the metal pads 302 and increase the bonding force between the metal pads 302 and the solder balls 304, making the structure of the solder balls 304 stable.

[0086] Optionally, the solder balls 304 are symmetrically arranged along the cover plate substrate 101, offering good appearance and facilitating processing; in this embodiment, the solder balls 304 are symmetrically arranged, that is, the metal pads 302 are symmetrically arranged, facilitating subsequent cutting of the wafer-level package structure of the MEMS device.

[0087] Optionally, the height of the solder ball 304 is not less than 100 um, making the structure of the solder ball 304 large enough for subsequent welding with external structures.

[0088] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A MEMS device wafer-level packaging method, characterized in that: include: Providing a second adhesive layer (102) on the cover substrate (101), and removing the second adhesive layer (102) at the first preset position; A groove (1012) is formed at a first end of the cover substrate (101) along the periphery of a first preset position; removing the remaining second adhesive layer (102); A carrier plate (105) is installed on the first end of the cover substrate (101), the cover substrate (101) at the first preset position being connected to the carrier plate (105); Removing material from a second end of the cover substrate (101) opposite to the first end by mechanical grinding, so that the slot (1012) becomes a through slot (1011); Disposing a first adhesive layer (201) at a second preset position of the second end of the cover substrate (101); The MEMS wafer (301) comprises a device structure and metal pads (302) arranged around the device structure, the cover substrate (101) and the first adhesive layer (201) corresponding to the first preset position encapsulate the device structure, and the metal pads (302) are arranged opposite to the through grooves (1011); Removing the carrier plate (105) to form a MEMS device wafer-level packaging structure; After removing the carrier board (105), the method further includes soldering tin on the metal pad (302); Before the carrier (105) is installed on the first end of the cover substrate (101), a third adhesive layer is provided on the first end of the cover substrate (101), and the cover substrate (101) and the carrier (105) are bonded via the third adhesive layer; After removing the carrier plate (105), the method further includes removing the third adhesive layer; Pressing a dry film onto the second end of the cover substrate (101), and removing the dry film outside the second preset position to form the first adhesive layer (201) at the second preset position; The cover substrate (101) and the MEMS wafer (301) are aligned by infrared rays so that the cover substrate (101) and the device structure, and the through groove (1011) and the metal pad (302) corresponding to the first preset position are respectively arranged relative to each other, and then the cover substrate (101) and the MEMS wafer (301) are pressed together.

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