Preparation method of micro-electro-mechanical packaging structure, micro-electro-mechanical sensor and electronic equipment

Abstract

The invention discloses a preparation method of a micro-electro-mechanical packaging structure, the micro-electro-mechanical packaging structure and electronic equipment. The preparation method comprises the steps that a substrate is provided, an electrical element is arranged in the substrate, and an electrical connection point of the electrical element is exposed to the substrate; dielectric material layers are arranged on the two surfaces of the substrate in the thickness direction; a through hole is formed, the through hole exposes the electric connection point or the through hole penetrates through the substrate and the two dielectric material layers; covering the two dielectric material layers with a dry film; partial parts of the two dry films are removed to expose a conduction area, and the through hole is located in the conduction area; and forming a conductor layer in the conduction region.

Description

Technical Field

[0001] The present invention relates to the field of micro-electromechanical technology, and more particularly to a method for preparing a micro-electromechanical packaging structure, a micro-electromechanical sensor, and an electronic device. Background Art

[0002] In related technologies, MEMS packaging structures can be fabricated using the RDL process. This process requires the application of dielectric layers on both sides of the substrate. Due to the weak bonding between the substrate and the dielectric layer, the dielectric layer is prone to warping, especially at the edges and corners. This warping can cause the dielectric layer to peel, reducing the yield rate of the printed circuit board.

[0003] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Summary of the Invention

[0004] An object of the present invention is to provide a new technical solution for a method for preparing a micro-electromechanical packaging structure.

[0005] According to a first aspect of the present invention, a method for preparing a micro-electromechanical system packaging structure is provided. The method comprises:

[0006] Providing a substrate, wherein an electrical component is disposed in the substrate, and electrical connection points of the electrical component are exposed on the substrate;

[0007] Disposing dielectric material layers on both surfaces of the substrate in a thickness direction;

[0008] Opening a through hole, wherein the through hole exposes the electrical connection point or the through hole passes through the substrate and the two dielectric material layers;

[0009] covering the two dielectric material layers with a dry film;

[0010] removing portions of the two dry films to expose a conductive area, wherein the through hole is located in the conductive area;

[0011] A conductor layer is formed in the conductive region.

[0012] Optionally, covering the two dielectric material layers with a dry film comprises:

[0013] Laminating a dry film on the two dielectric material layers;

[0014] The dry film is cured.

[0015] Optionally, the two dry films are cured sequentially by light irradiation.

[0016] Optionally, partially removing the two dry films to expose the conductive area includes:

[0017] The dry film located in the conductive area is shielded to avoid light exposure.

[0018] Optionally, the dry film forms the conductive area after being cured.

[0019] Optionally, the dry film is a photosensitive polymer material.

[0020] Optionally, after the step of performing electroplating or chemical plating on the conductive area to form a conductor layer, the method further includes:

[0021] Remove all dry film.

[0022] Optionally, remove all dry film steps, including:

[0023] placing a developer on the dry film to be removed;

[0024] The developer reacts with the dry film to remove the dry film.

[0025] Optionally, after removing all dry film steps, including:

[0026] Solder resist layers are provided on both sides of the substrate in a thickness direction.

[0027] Optionally, after the step of providing solder resist layers on both sides of the substrate in the thickness direction, the method further includes:

[0028] A sound hole is formed penetrating the two solder resist layers and a portion between the two solder resist layers in a thickness direction.

[0029] According to a second aspect of the present application, a micro-electromechanical sensor is provided. The sensor is manufactured according to the manufacturing method described in the present application.

[0030] According to a third aspect of the present application, an electronic device is provided, which includes the micro-electromechanical sensor described in the present application.

[0031] In the embodiment of the present application, a dry film is provided on the surfaces of the two dielectric material layers facing away from the substrate. The dry film can effectively prevent the dielectric material layers from warping, thereby improving the yield rate of the MEMS packaging structure.

[0032] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0034] Figure 14 is a flow chart of a method for preparing a micro-electromechanical packaging structure according to an embodiment of the present application.

[0035] Figures 2 to 13 Schematic diagram of a method for preparing a micro-electromechanical system packaging structure according to an embodiment of the present application.

[0036] Description of reference numerals:

[0037] 100. Substrate; 101. Chip; 102. First solder pad; 103. Dielectric material layer; 104. Through hole; 105. Dry film; 106. Conductor layer; 107. Shading plate; 108. Glass plate; 109. Conductive area; 110. Solder mask layer; 111. Second solder pad; 112. Acoustic hole. DETAILED DESCRIPTION

[0038] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0039] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0040] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0041] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0042] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0043] According to one embodiment of the present application, a method for preparing a micro-electromechanical packaging structure is provided. Figure 1 As shown, the preparation method comprises:

[0044] Providing a substrate 100, wherein electrical components are disposed in the substrate 100, and electrical connection points of the electrical components are exposed on the substrate 100;

[0045] A dielectric material layer 103 is provided on both surfaces of the substrate 100 in the thickness direction;

[0046] A through hole 104 is formed, wherein the through hole 104 exposes the electrical connection point or the through hole 104 passes through the substrate 100 and the two dielectric material layers 103;

[0047] Covering the two dielectric material layers 103 with a dry film 105;

[0048] Partially removing the two dry films 105 to expose the conductive area 109 , where the through hole 104 is located;

[0049] A conductive layer 106 is formed in the conductive region 109 .

[0050] Specifically, a MEMS package structure encapsulates a microelectromechanical system (MEMS) device to protect it and isolate it from the external environment, while also providing connectivity to external circuits. This MEMS package can be either a single-chip integrated package or a multi-chip assembly package.

[0051] The substrate 100 is used to carry the chip 101 and provide circuits connecting the chips 101 and the chip 101 to external circuits. Optionally, the substrate 100 is a carrier or a wafer. The carrier can be, but is not limited to, epoxy resin, bismaleimide triazine resin (Bismaleimide Triazine, abbreviated as BT), Ajinomoto Build-up Film (ABF), Modified Imidazole System (MIS). The wafer can be single crystal silicon, polycrystalline silicon, etc. Typically, the size of the substrate 100 is larger than the side size of the wafer.

[0052] Electrical components include, for example, active devices and passive devices. Active devices include, for example, diodes, transistors, and integrated circuit chips 101. Passive devices include, for example, capacitors, inductors, and resistors. Electrical components are connected to other components via electrical connection points. For example, the electrical connection points are provided with first pads 102. Connections to other components are made via first pads 102. The electrical components are embedded within substrate 100, with first pads 102 exposed on the surface of substrate 100.

[0053] Dielectric material layer 103 is a material layer that acts as an insulator between two electrodes (e.g., pads). Dielectric material layer 103 prevents electrical breakdown between the electrodes. Dielectric material layer 103 is an inorganic or organic material. Examples of inorganic materials include SiO2, Al2O3, Si3N4, HfO2, and TiO2; examples of organic materials include PMMA, ABF, PS, CYTOP, PVA, PVP, and PP. The thickness of dielectric material layer 103 is 10 to 100 μm.

[0054] Through-hole 104 is used to form conductive layer 106. For example, through-hole 104 is formed in dielectric material layer 103. Through-hole 104 exposes first pad 102, which can be connected to other circuits. Alternatively, through-hole 104 passes through substrate 100 and both dielectric material layers 103. The conductive layer 106 thus formed can conduct electricity to components on both dielectric material layers 103. For example, through-hole 104 can be formed by laser etching.

[0055] When exposed to light of a predetermined frequency, the dry film 105 undergoes a polymerization reaction to form a stable film layer that adheres to the surface of the dielectric material layer 103. The dry film 105 can resist electroplating and etching, etc. For example, the dry film 105 can be a photosensitive polymer material. For example, the dry film 105 may include a film-forming resin, a monomer, an initiator, a dye, a plasticizer, a stabilizer, an adhesive, etc. The uncured dry film 105 is a flexible film material with adhesive properties.

[0056] The dry film 105 is applied to the surface of the dielectric material layer 103 by lamination. The dry film 105 is then cured by irradiation with light. The dry film 105 covers the surface of the dielectric material layer 103 and adheres to the dielectric material layer 103. The dielectric material layer 103 has a weak bonding strength with the substrate 100, which can cause the dielectric material layer 103 to warp easily, especially at the corners. The dry film 105 has a predetermined structural strength, and the bonding strength between the dry film 105 and the dielectric material layer 103 is high, thereby effectively preventing the dielectric material layer 103 from warping.

[0057] A portion of the dry film 105 is removed by etching, scraping, chemical etching, or the like to expose the conductive region 109, while retaining the remaining portion of the dry film 105. The opening of the through hole 104 is located within the conductive region 109. During electroplating or chemical plating, the chemical liquid can enter the conductive region 109 and enter the through hole 104 through the opening, thereby forming a conductive layer on the conductive region 109 and the inner wall of the through hole 104.

[0058] In the embodiment of the present application, dry films 105 are provided on the surfaces of the two dielectric material layers 103 facing away from the substrate 100. The dry films 105 can effectively prevent the dielectric material layers 103 from warping, thereby improving the yield rate of the MEMS packaging structure.

[0059] The thinner the dry film 105, the weaker its reinforcing effect on the dielectric material layer 103. Conversely, the thicker the dry film 105, the more difficult it is to remove in subsequent steps. Optionally, the thickness of the dry film 105 is between 20 μm and 50 μm. Within this range, the dry film 105 significantly strengthens the dielectric material layer 103 while facilitating removal in subsequent steps.

[0060] In one example, covering the two dielectric material layers 103 with a dry film 105 includes:

[0061] Laminating a dry film 105 on the two dielectric material layers 103;

[0062] The dry film 105 is cured.

[0063] As described above, the dry film 105 is laminated on the surfaces of the two dielectric material layers 103 facing away from the substrate 100. The dry film 105 evenly covers the dielectric material layers 103. The dry film 105 is irradiated with ultraviolet light to cure the dry film 105.

[0064] In one example, the two dry films 105 are cured sequentially by light irradiation.

[0065] like Figure 7 、 Figure 8 As shown, the ultraviolet light first irradiates the dry film 105 on one of the dielectric material layers 103 and then irradiates the dry film 105 on the other dielectric material layer 103 so that the two dry films 105 can be uniformly cured.

[0066] In one example, the two dry films 105 are partially removed to expose the conductive area 109, including:

[0067] The dry film 105 located in the conductive area 109 is shielded to avoid light exposure.

[0068] like Figure 7 、 Figure 8 As shown, the ultraviolet light is emitted after passing through the glass plate 108. A light shielding plate 107 is provided on the glass plate 108. The light shielding plate 107 can block the ultraviolet light exposure to prevent the dry film 105 located below the light shielding plate 107 from curing. The light shielding plate 107 has a light-transmitting area. For example, the light-transmitting area is a light-through hole provided in the light shielding plate 107. The ultraviolet light passes through the light-transmitting area and irradiates the dry film 105. The dry film 105 located there is cured and covers the dielectric material layer 103. In this way, the conductive area 109 can be exposed by removing the uncured dry film 105. The dry film 105 has a predetermined thickness. After curing, the dry film 105 forms the conductive area 109. The conductive area is a recessed area, which can accommodate a chemical liquid. The conductive layer 106 is formed in the recessed area. The conductive layer 106 can be formed by electroplating, chemical plating, magnetron sputtering, etc.

[0069] The uncured dry film 105 can be easily removed. For example, scraping or chemical etching can be used to remove the uncured dry film 105. For example, the dry film 105 is generally made of a material that is acid-resistant but not alkali-resistant. Chemical etching uses an alkaline agent to corrode the dry film 105.

[0070] In one example, after the step of electroplating or chemically plating the conductive region 109 to form the conductor layer 106, the method further includes:

[0071] All dry film 105 is removed.

[0072] like Figures 10 and 11 As shown, after the conductor layer 106 is formed, a large area of ​​the conductor layer 106 is exposed, posing a risk of short circuits. It is necessary to cover at least a portion of the conductor layer 106. After removing the dry film 105, the surface of the conductor layer 106 facing away from the substrate 100 and the surface along the thickness direction are exposed. A solder mask 110 is then applied over the conductor layer 106. The solder mask 110 acts as an insulator and solder resist, effectively protecting the conductor layer 106.

[0073] In one example, the step of removing all dry films 105 includes:

[0074] Setting a developer on the dry film 105 to be removed;

[0075] The developer reacts with the dry film 105 to remove the dry film 105 .

[0076] For example, the developer is an alkaline solution, which can easily and effectively dissolve the dry film 105, so that the dry film 105 can be removed quickly and thoroughly.

[0077] In one example, after removing all dry films 105, the following steps are included:

[0078] A solder resist layer 110 is provided on both sides of the substrate 100 in a thickness direction.

[0079] like Figure 12 As shown, solder resist layer 110 is an insulating layer formed on the surface of conductive layer 106. Solder resist layer 110 includes solder resist ink. Solder resist ink includes resin, hardener, filler, and additives. Additives include solvents, hardening accelerators, and antioxidants. The solder resist ink is applied to conductive layer 106 and dielectric layer 103 by coating. Curing of the solder resist ink is achieved through heat curing. For example, the curing process includes two stages: pre-curing and post-curing. Pre-curing involves a low-temperature bake for a period of time to evaporate the solvent in the solder resist ink, ensuring that the solder resist ink does not adhere to conductive layer 106 and dielectric layer 103 when exposed to light. The pre-curing temperature is, for example, 70°C to 80°C. Post-curing typically involves a high-temperature bake for a period of time to cross-link the solder resist ink molecules and achieve hardening. The post-curing temperature is, for example, 150°C to 160°C. A window is opened in solder resist layer 110 to expose second solder pads 111. Second solder pads 111 are used for electrical connection to external circuits.

[0080] In one example, after the step of providing the solder resist layer 110 on both sides of the substrate 100 in the thickness direction, the method further includes:

[0081] An acoustic hole 112 is formed penetrating the two solder resist layers 110 and a portion between the two solder resist layers 110 in a thickness direction.

[0082] Acoustic vias 112 are through-holes 104 that penetrate the two solder resist layers 110, the two dielectric material layers 103, and the substrate 100. External gases, sound waves, and the like can pass through acoustic vias 112 from one side of the substrate 100 to the other, where they can be sensed by the sensor chip within the package. Acoustic vias 112 are formed, for example, by mechanical drilling.

[0083] According to a second embodiment of the present application, a micro-electromechanical system packaging structure is provided, which is manufactured according to the manufacturing method of the present application.

[0084] For example, a micro-electromechanical system package structure typically includes a package housing, a package cover, a chip 101, leads, etc. The package housing or package cover is manufactured using the above-described manufacturing method. Chip 101 may be, for example, a microphone chip, a temperature sensor chip, a humidity sensor chip, a gas sensor chip, a memory chip, a communication chip, an ASIC chip, a microprocessor chip, etc. Part of chip 101 is disposed within the package housing, while part of chip 101 is embedded within the package housing or package cover.

[0085] According to a third embodiment of the present application, an electronic device is provided. The electronic device includes the microelectromechanical packaging structure of the present application. The electronic device is, for example, a mobile phone, a laptop computer, a tablet computer, a television, a smartwatch, a VR device, an AR device, an XR device, etc.

[0086] <Example>

[0087] Figures 2 to 13 FIG. 1 is a schematic diagram of a method for preparing a micro-electromechanical system package structure according to an embodiment of the present application. In this example, the preparation method includes:

[0088] (1) Provide a carrier board, wherein electrical components are arranged in the carrier board, and the electrical connection points of the electrical components are exposed on the carrier board. Figure 2 As shown, the electrical component is a chip 101. Chip 101 includes a plurality of first solder pads 102. The plurality of first solder pads 102 are exposed on one surface of a carrier. The carrier is made of epoxy molding compound (EMC). For example, chip 101 can be an ASIC chip, an MCU chip, a memory chip, a communication chip, etc.

[0089] (2) Thinning the carrier board. Figure 3As shown, the side of the carrier opposite to the first pad 102 is thinned by grinding to expose the surface of the chip 101 on this side. This step can make the thickness of the MEMS package structure smaller to meet the demand for miniaturization of electrical components.

[0090] (3) A dielectric material layer 103 is provided on both surfaces of the carrier in the thickness direction. Figure 4 As shown, the dielectric material layer 103 is made of polypropylene (PP) and is bonded to two surfaces of the carrier by lamination.

[0091] (4) Open through holes 104 on the two dielectric material layers 103. Figure 5 As shown, the positions of the through holes 104 correspond to the positions of the two first pads 102 of the chip 101 to expose the first pads 102. The through holes 104 are also provided at the positions of the conductors used to connect the upper and lower surfaces. For example, a through hole 104 is provided on each of the left and right sides of the chip 101.

[0092] (5) Cover the two dielectric material layers 103 with a dry film 105. Figure 6 As shown, two dry films 105 are pressed onto the surfaces of two dielectric material layers 103 facing away from the carrier. The dry films 105 are adhesive and adhere to the dielectric material layers 103.

[0093] (6) Expose the front side and solidify the dry film 105. Figure 7 As shown, dry film 105 is irradiated with ultraviolet light to cure it. The ultraviolet light passes through glass plate 108 and irradiates the front surface of dry film 105. A light shielding plate 107 is positioned outside glass plate 108. Light shielding plate 107 blocks portions of dry film 105, such as the area directly below light shielding plate 107. The light-transmitting area of ​​light shielding plate 107 allows ultraviolet light to pass through. The area of ​​dry film 105 directly below the light-transmitting area is cured after irradiation with ultraviolet light. The cured dry film 105 is firmly bonded to dielectric material layer 103. The cured dry film 105 has a predetermined structural strength and maintains a fixed shape. Under the action of the cured dry film 105, dielectric material layer 103 can maintain a fixed shape, thereby preventing warping of dielectric material layer 103 during subsequent processing. The area of ​​dry film 105 below light shielding plate 107 remains flexible because it is not irradiated.

[0094] (7) Back exposure. Figure 8As shown, the reverse side of the carrier substrate is exposed to ultraviolet light to cure the dry film 105 on the reverse side. Similarly, the area of ​​dry film 105 directly below the light-transmitting region is cured after exposure to ultraviolet light. The cured dry film 105 effectively prevents warping of the dielectric material layer 103 during subsequent processing. The area of ​​dry film 105 below the light shield 107 remains flexible because it is not exposed to ultraviolet light.

[0095] (8) Parts of the two dry films 105 are removed to expose the conductive area 109, where the through hole 104 is located. Figure 9 As shown, uncured dry film 105 is removed by development to form conductive region 109. For example, a developer is applied or sprayed on the area of ​​dry film 105 to be removed. The developer reacts with dry film 105 for a set time. During the reaction, the dry film 105 in the set area is damaged, dissolved, and loses adhesion. For example, dry film 105 is made of an acid-resistant but alkali-resistant material. The developer is an alkaline liquid to dissolve dry film 105. After the set reaction time, the dry film is rinsed with deionized water to remove the reaction products. The deionized water or other liquid can be removed by high-speed spin drying.

[0096] The dry film 105 in a designated area is removed to form a conductive area 109. The conductive area 109 is arranged around the through hole 104 and exposes the through hole 104. The remaining dry film 105 forms a boundary of the conductive area 109.

[0097] (9) Electroplating or chemical plating is performed in the conductive area 109 to form the conductor layer 106. Figure 10 As shown, after electroplating, the conductor layer 106 is attached to the surfaces of the two dielectric material layers 103 facing away from the carrier and the inner wall of the through hole 104. The conductor layer 106 is connected to the first pad 102 and forms a conductive path between the two dielectric material layers 103.

[0098] (10) Remove the remaining dry film 105 on the two dielectric material layers 103. Figure 11 As shown, the dry film 105 is soaked in an alkaline solution to dissolve the remaining dry film 105. The dissolved material is removed by spin drying. At this time, the conductor layer 106 on the surface of the two dielectric material layers 103 is exposed.

[0099] (11) A solder resist layer 110 is provided on the two dielectric material layers 103. Figure 12As shown, solder mask layer 110 is solder mask ink. The main components of solder mask ink include resin, hardener, filler, and additives. Additives include solvents, hardening accelerators, and antioxidants. The solder mask ink is printed on the two dielectric material layers 103. The solder mask ink is then cured to form solder mask layer 110. Curing is primarily achieved by heating. Curing consists of two stages: pre-curing and post-curing. Pre-curing involves baking at a bottom temperature, for example, 75°C. During the pre-curing process, the solvent in the solder mask ink evaporates, forming a film. Post-curing is typically performed at a higher temperature, for example, 155°C. During this process, the molecules of the solder mask ink undergo a cross-linking reaction, hardening the film layer to form solder mask layer 110. Solder mask layer 110 is firmly attached to dielectric material layer 103 and conductor layer 106. Windows are opened in solder mask layer 110 by etching, drilling, or other methods to expose second solder pads 111. The second pad 111 is used for conducting with an external circuit.

[0100] (12) A sonic hole 112 is formed that penetrates the two solder resist layers 110 and the portion between the two solder resist layers 110 in the thickness direction.

[0101] like Figure 13 As shown, acoustic holes 112 are through-holes that penetrate the two solder mask layers 110, the two dielectric material layers 103, and the carrier. External gases, sound waves, and the like can pass through acoustic holes 112 from one side of the carrier to the other, where they can be sensed by the sensor chip within the package structure. For example, acoustic holes 112 can be formed by mechanical drilling. The diameter and number of acoustic holes 112 are not limited here; those skilled in the art can configure them based on actual needs.

[0102] In this example, since the dry films 105 are disposed on both sides of the carrier in the thickness direction, the dielectric material layers 103 on both sides of the carrier can be effectively prevented from warping.

[0103] It should be noted that the conductive layer is not limited to one; multiple conductive layers can be provided along the thickness of the substrate to meet the conductivity requirements of different components. The multiple conductive layers are separated by an insulating layer. The insulating layer can be, for example, solder mask ink.

[0104] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0105] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for preparing a micro-electromechanical system packaging structure, characterized in that: include: Providing a substrate (100), wherein an electrical component is disposed in the substrate (100), and electrical connection points of the electrical component are exposed on the substrate (100); Disposing dielectric material layers (103) on two surfaces of the substrate (100) in a thickness direction; A through hole (104) is formed, wherein the through hole (104) exposes the electrical connection point or the through hole (104) passes through the substrate (100) and the two dielectric material layers (103); Covering the two dielectric material layers (103) with a dry film (105); Partially removing the two dry films (105) to expose a conductive area (109), wherein the through hole (104) is located in the conductive area (109); A conductor layer (106) is formed in the conductive region (109).

2. The preparation method according to claim 1, characterized in that Covering the two dielectric material layers (103) with a dry film (105), comprising: Laminating a dry film (105) on the two dielectric material layers (103); The dry film (105) is cured.

3. The preparation method according to claim 1, characterized in that The two dry films (105) are cured in sequence by light irradiation.

4. The preparation method according to claim 3, characterized in that Partially removing the two dry films (105) to expose the conductive area (109), comprising: The dry film (105) located in the conductive area (109) is shielded to avoid light exposure.

5. The preparation method according to claim 4, characterized in that After the dry film (105) is cured, it forms the conductive area (109).

6. The preparation method according to claim 1, characterized in that The dry film (105) is a photosensitive polymer material.

7. The preparation method according to claim 1, characterized in that After the step of performing electroplating or chemical plating on the conductive area (109) to form a conductor layer (106), the method further comprises: All dry film (105) is removed.

8. The preparation method according to claim 7, characterized in that The step of removing all dry films (105) comprises: placing a developer on the dry film (105) to be removed; The developer reacts with the dry film (105) to remove the dry film (105).

9. The preparation method according to claim 7, characterized in that After removing all dry films (105), the steps include: Solder resist layers (110) are provided on both sides of the substrate (100) in a thickness direction.

10. The preparation method according to claim 9, characterized in that After the step of providing solder resist layers (110) on both sides of the substrate (100) in the thickness direction, the method further includes: A sound hole (112) is formed penetrating the two solder resist layers (110) and a portion between the two solder resist layers (110) in a thickness direction.

11. A micro-electromechanical sensor, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 10.

12. An electronic device, characterized in that: Comprising the micro-electromechanical sensor according to claim 11.

Images