Heat dissipation and electromagnetic shielding packaging structure and manufacturing method thereof

Abstract

The present invention provides a heat dissipation and electromagnetic shielding packaging structure and a manufacturing method thereof, comprising a substrate, a chip, a plastic encapsulation body, a high thermal conductivity interface layer, and a metal shielding layer. Several chips are flip-chip mounted on the upper surface of the substrate, the plastic encapsulation body covers the substrate and all the chips, the high thermal conductivity interface layer covers the top and side surfaces of the plastic encapsulation body, and the metal shielding layer covers the outer surface of the high thermal conductivity interface layer. The thermal conductivity of the high thermal conductivity interface layer is greater than that of the plastic encapsulation body. The present invention provides a high thermal conductivity interface layer with a thermal conductivity intermediate between the metal shielding layer and the plastic encapsulation body, allowing the layer to act as a thermal bridge, rapidly diffusing heat generated by the chip to the metal shielding layer. This significantly reduces the thermal resistance between the plastic encapsulation body and the shielding layer. Furthermore, the high thermal conductivity interface layer acts as a buffer layer, reducing interfacial stress during thermal cycling and preventing delamination and microcracking of the metal shielding layer, thereby ensuring electromagnetic shielding effectiveness and mechanical reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular to a packaging structure for heat dissipation and electromagnetic shielding and a manufacturing method thereof. Background Art

[0002] As electronic products become more and more complex with more functions, the problem of electromagnetic interference between different modules becomes more and more prominent. Therefore, electronic equipment must have good anti-electromagnetic interference and heat dissipation capabilities.

[0003] Existing technologies for electromagnetic shielding and heat dissipation of chips often involve placing a metal casing around the chip packaging structure or forming a metal film on the chip packaging structure's surface through vacuum sputtering. However, both methods have significant drawbacks: installing a metal casing increases the size of the chip packaging structure, making it difficult to install in smaller packaging structures. It also increases the package's bulk, failing to meet the demands of increasingly sophisticated electronic products. While sputtering a metal film on the package structure's surface can meet the electromagnetic shielding needs of many products, the thermal conductivity of the plastic outer layer of the package structure is typically very low (0.2-2.5 W / mK), while the metal film has an extremely high thermal conductivity (approximately 400 W / mK for copper and 429 W / mK for silver). Direct contact between the two creates interfacial thermal resistance, which not only reduces the metal film's heat dissipation performance but also leads to delamination or microcracks during thermal cycling, directly impacting electromagnetic shielding effectiveness. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a packaging structure for heat dissipation and electromagnetic shielding, which is used to solve the problem in the prior art that the metal film formed by sputtering and the plastic package body still have contact thermal resistance, which easily reduces the heat dissipation and electromagnetic shielding effects. At the same time, the present invention will also provide the packaging structure for heat dissipation and electromagnetic shielding and its manufacturing method.

[0005] To achieve the above-mentioned and other related purposes, the present invention provides the following technical solutions:

[0006] A first aspect of the present invention provides a packaging structure for heat dissipation and electromagnetic shielding, comprising a substrate, a chip, a plastic package, a high thermal conductivity interface layer and a metal shielding layer, wherein several chips are flip-chip mounted on the upper surface of the substrate, the plastic package covers the substrate and covers all the chips, the high thermal conductivity interface layer covers the top surface and side surfaces of the plastic package, the metal shielding layer covers the outer surface of the high thermal conductivity interface layer, and the thermal conductivity of the high thermal conductivity interface layer is greater than the thermal conductivity of the plastic package.

[0007] The thermal conductivity of the plastic package is very low. By providing a high-thermal conductivity interface layer with a thermal conductivity between the metal shielding layer and the plastic package, it acts as a thermal bridge, rapidly diffusing heat generated by the chip to the metal shielding layer, which then dissipates it into the environment through the metal shielding layer. Furthermore, the thermal expansion coefficients of the metal shielding layer and the plastic package differ significantly. The high-thermal conductivity interface layer acts as a buffer layer, reducing interfacial stress during thermal cycling and ensuring the adhesion strength of the metal shielding layer, thereby enhancing electromagnetic shielding reliability. Furthermore, the present invention encapsulates the high-thermal conductivity interface layer and metal shielding layer on all five sides of the plastic package, achieving maximum heat dissipation and electromagnetic shielding effectiveness.

[0008] Furthermore, the high thermal conductivity interface layer has a grid structure, that is, a plurality of grooves are uniformly distributed on the surface of the high thermal conductivity interface layer.

[0009] The high thermal conductivity interface layer can reduce the thermal resistance between the plastic package and the metal shielding layer, and its grid structure can optimize the heat dissipation path, increase the heat dissipation surface area, and thus improve the thermal conductivity efficiency and heat dissipation performance, effectively reducing the operating temperature of the chip. In addition, the grid grooves of the high thermal conductivity interface layer provide three-dimensional anchor points for the metal shielding layer when it is formed by sputtering or electroplating. After sputtering, the metal is embedded in the grid grooves, reducing the risk of interface delamination and increasing the contact area, which greatly improves the peel strength between the high thermal conductivity interface layer and the metal shielding layer. In addition, in the prior art, direct metal coverage of the plastic package is prone to microcracks, affecting the shielding effectiveness; the metal shielding layer of the present invention can completely fill the grooves and fully cover the high thermal conductivity interface layer, avoiding discontinuity of the metal shielding layer due to insufficient surface roughness of the plastic package.

[0010] Furthermore, the width of the groove is between 10 and 30 μm, the depth of the groove is between 10 and 20 μm, and the spacing between the grooves is between 20 and 50 μm.

[0011] The higher the aspect ratio of the trench, the more difficult it is for the sputtered metal to evenly cover the bottom and sidewalls of the trench. Controlling the aspect ratio of the trench to ≤1:1 can prevent the metal from accumulating at the opening due to excessively deep trenches.

[0012] Furthermore, the trench sidewall inclination angle (i.e., the angle between the sidewall and the top surface) is 60-90°. The trench sidewall angle is controlled during the etching process to reduce the sputtering shadow effect and ensure full coverage of the sputtered metal. However, reducing the inclination angle increases the cost and difficulty of etching, so the trench sidewall inclination angle is controlled to 80-90°.

[0013] Furthermore, the groove is in a triangular, rectangular or hexagonal honeycomb shape.

[0014] Furthermore, the high thermal conductivity interface layer is made of a high thermal conductivity interface material, which includes a matrix, fillers and other additives, and the fillers include high thermal conductivity conductive fillers and / or high thermal conductivity non-conductive fillers.

[0015] When only highly thermally conductive fillers are used as fillers, the interface layer becomes conductive, effectively reducing thermal interface impedance while maintaining electromagnetic shielding continuity and improving electromagnetic shielding effectiveness. When only highly thermally conductive non-conductive fillers are used as fillers, the insulation properties of the interface layer are maintained, ensuring electrical isolation while effectively reducing thermal resistance. When a combination of highly thermally conductive and non-conductive fillers is used as fillers, electrical conductivity is enhanced while further reducing thermal resistance.

[0016] Wherein, the matrix is ​​selected from epoxy resin, silicone resin or polyimide; the high thermal conductivity and conductive filler is selected from at least one of silver powder, copper powder, graphene, carbon nanotubes, and silicon carbide; the high thermal conductivity and non-conductive filler is selected from at least one of aluminum nitride, boron nitride, diamond or bismuth telluride.

[0017] The present invention selects a plastic package with a relatively high thermal conductivity, the thermal conductivity of the plastic package is about 2.5 W / mK, the thermal conductivity of the high thermal conductivity interface layer of the present invention is ≥3 W / mK, and further by regulating the selection and ratio of the high thermal conductivity interface material, the thermal conductivity of the high thermal conductivity interface layer is made ≥5 W / mK.

[0018] Furthermore, the addition amount of the filler is 30-70 wt%.

[0019] Furthermore, solder balls are provided on the lower surface of the substrate through a redistribution layer, and bottom filling glue is filled between the chip and the substrate.

[0020] A second aspect of the present invention provides a method for manufacturing a heat dissipation and electromagnetic shielding packaging structure, comprising the following steps:

[0021] (1) Providing a substrate with through-silicon vias, connecting several chips to the upper surface of the substrate through micro-pads, and performing bottom filling between the substrate and the chips;

[0022] (2) Plastic encapsulating the chips on the substrate so that the formed plastic encapsulation body covers all the chips, and then grinding and thinning the plastic encapsulation body;

[0023] (3) Grinding the lower surface of the substrate to form a solder pad, and preparing a redistribution layer and solder balls on the lower surface;

[0024] (4) Mounting the substrate on a carrier coated with a peeling layer, and then cutting it into individual package structures;

[0025] (5) Coating a high thermal conductivity interface material on the top surface and side surface of the plastic package of a single packaging structure, and forming a high thermal conductivity interface layer after solidification, and etching grooves on the surface of the high thermal conductivity interface layer using a laser etching process to form a high thermal conductivity interface layer with a grid structure;

[0026] (6) Plasma cleaning is performed on the high thermal conductivity interface layer of the grid structure, and then a metal shielding layer is formed on the surface of the high thermal conductivity interface layer by sputtering and / or electroplating.

[0027] Preferably, in step (4), the single package structure is cut into a trapezoidal columnar structure or a tapered columnar structure. Compared with a rectangular columnar structure, the trapezoidal columnar structure or the tapered columnar structure has a larger surface area and better heat dissipation and electromagnetic shielding effects. Moreover, under the same bottom area condition, the four sides of the trapezoidal columnar structure or the tapered columnar structure are thinned, which can improve the heat dissipation effect. At the same time, the volume and weight of the trapezoidal columnar structure or the tapered columnar structure are smaller, meeting the requirements of lightweight.

[0028] Preferably, in step (5), the thickness of the high thermal conductivity interface layer is between 20 and 100 μm, and the groove depth is ≤ 1 / 2 of the thickness of the high thermal conductivity interface layer, so as to avoid the groove being too deep to weaken the support strength, adhesion and thermal conductivity efficiency of the interface layer.

[0029] Preferably, in step (6), a stepped metal deposition process is used to deposit a metal shielding layer on the high thermal conductivity interface layer of the grid structure. Specifically, the process comprises the following steps: first, sputtering a thin layer with high adhesion on the surface of the high thermal conductivity interface layer to ensure full coverage of the grooves, and then sputtering or electroplating a thick layer to thicken the layer to ensure uniform coverage of the metal shielding layer and high thermal conductivity and shielding effect.

[0030] Furthermore, the high-adhesion thin layer is made of titanium, chromium or nickel, and the thickness of the high-adhesion thin layer is 10-50 nm; the thick layer sputtering or electroplating is made of copper or silver, and the thickness of the metal shielding layer is 5-30 μm.

[0031] Furthermore, an ultra-thin inert protective film is sputtered or coated on the outside of the metal shielding layer to extend the service life and improve weather resistance. The ultra-thin inert protective film is selected from silicon nitride, aluminum oxide, aluminum nitride or polymer coating.

[0032] As described above, the heat dissipation and electromagnetic shielding packaging structure and the manufacturing method thereof of the present invention have the following beneficial effects:

[0033] 1. The present invention sets a high thermal conductivity interface layer with a thermal conductivity between the metal shielding layer and the plastic package, so that the layer acts as a thermal bridge to quickly diffuse the heat generated by the chip to the metal shielding layer, significantly reducing the thermal resistance between the plastic package and the shielding layer. At the same time, the high thermal conductivity interface layer acts as a buffer layer, which can reduce the interface stress under thermal cycling and avoid delamination and microcracks of the metal shielding layer, thereby ensuring electromagnetic shielding effectiveness and mechanical reliability.

[0034] 2. The high thermal conductivity interface layer with a grid structure can increase the heat dissipation area, optimize the heat dissipation path, and thus improve the thermal conductivity efficiency and heat dissipation performance; and the grid grooves provide three-dimensional anchor points for the metal shielding layer when it is formed by sputtering or electroplating, and increase the contact area. The metal is embedded in the grid grooves after sputtering, reducing the risk of interface stratification and avoiding the discontinuity of the metal layer caused by insufficient surface roughness of the plastic package.

[0035] 3. The present invention formulates the material of the high thermal conductivity interface layer and controls the thermal conductivity to be ≥5 W / mK, which not only enables it to have high thermal conductivity and electrical conductivity, effectively reducing the thermal interface impedance while maintaining electromagnetic shielding continuity and improving the electromagnetic shielding effect; it also enables it to have excellent insulation properties, effectively reducing thermal resistance while ensuring electrical isolation; therefore, the formula can be adjusted to make the high thermal conductivity interface layer flexibly adaptable to different packaging requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a structural schematic diagram of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 1 of the present invention.

[0037] Figure 2 This is a structural schematic diagram of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 2 of the present invention.

[0038] Figure 3 Schematic diagram of the preparation process of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 2 of the present invention Figure 1 .

[0039] Figure 4 Schematic diagram of the preparation process of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 2 of the present invention Figure 2 .

[0040] Figure 5 Schematic diagram of the preparation process of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 2 of the present invention Figure 3 .

[0041] Figure 6 Schematic diagram of the preparation process of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 2 of the present invention Figure 4 .

[0042] Figure 7Schematic diagram of the preparation process of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 2 of the present invention Figure 5 .

[0043] Figure 8 Schematic diagram of the preparation process of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 2 of the present invention Figure 6 .

[0044] Figure 9 Schematic diagram of the preparation process of the heat dissipation and electromagnetic shielding packaging structure disclosed in Example 2 of the present invention Figure 7 .

[0045] Figure 10 Schematic diagram of the structure of the high thermal conductivity interface layer disclosed in Example 2 of the present invention.

[0046] Figure 11 This is a schematic structural diagram of the high thermal conductivity interface layer disclosed in Example 3 of the present invention.

[0047] Component number description

[0048] 100, substrate; 200, chip; 300, plastic package; 400, high thermal conductivity interface layer; 410, groove; 500, metal shielding layer; 600, redistribution layer; 700, solder ball; 800, carrier. DETAILED DESCRIPTION

[0049] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0050] Example 1

[0051] This embodiment provides a heat dissipation and electromagnetic shielding packaging structure, such as Figure 1 As shown, it includes a substrate 100, a chip 200, a solder ball 700, a plastic package 300, a high thermal conductivity interface layer 400 and a metal shielding layer 500. Multiple chips are flip-chip mounted on the upper surface of the substrate. The solder balls are connected to the lower surface of the substrate through a redistribution layer 600. The chip and the substrate are filled with bottom filling glue. The plastic package covers the upper part of the substrate and covers all the chips. The plastic package has a rectangular columnar structure. The high thermal conductivity interface layer is covered on the top surface and side surfaces of the plastic package. The metal shielding layer is covered on the outer surface of the high thermal conductivity interface layer, that is, the high thermal conductivity interface layer is located between the plastic package and the metal shielding layer. The thermal conductivity of the high thermal conductivity interface layer is greater than that of the plastic package, thereby serving as a thermal bridge to reduce the thermal resistance between the plastic package and the metal shielding layer.

[0052] The high thermal conductivity interface layer is a planar structure with uniform thickness. The high thermal conductivity interface layer is made of a high thermal conductivity interface material. The high thermal conductivity interface material includes 50wt% epoxy resin and 50wt% aluminum nitride particles.

[0053] Example 2

[0054] This embodiment provides a heat dissipation and electromagnetic shielding packaging structure, such as Figure 2 As shown, it includes a substrate 100, a chip 200, a solder ball 700, a plastic package 300, a high thermal conductivity interface layer 400 and a metal shielding layer 500. Multiple chips are flip-chip mounted on the upper surface of the substrate, and the solder balls are connected to the lower surface of the substrate through a redistribution layer. Bottom filling glue is filled between the chip and the substrate. The plastic package covers the upper part of the substrate and covers all the chips. The plastic package has a trapezoidal columnar structure. The high thermal conductivity interface layer is covered on the top surface and four side surfaces of the plastic package. The metal shielding layer is covered on the outer surface of the high thermal conductivity interface layer, that is, the high thermal conductivity interface layer is located between the plastic package and the metal shielding layer. The thermal conductivity of the high thermal conductivity interface layer is greater than that of the plastic package, thereby serving as a thermal bridge to reduce the thermal resistance between the plastic package and the metal shielding layer.

[0055] Among them, such as Figure 10 As shown, the high thermal conductivity interface layer has a grid structure, and the surface of the high thermal conductivity interface layer is evenly distributed with multiple rectangular grooves 410, with the angle between the sidewalls of the rectangular grooves and the top surface being 90 degrees. The thickness of the high thermal conductivity interface layer is 50μm, and the rectangular grooves are 20μm deep, 25μm wide, and 30μm apart. The high thermal conductivity interface layer is made of a high thermal conductivity interface material, which includes 25wt% epoxy resin, 40wt% graphene nanosheets, 20wt% silver nanowires, 10wt% silicon carbide powder, and 5wt% curing agent.

[0056] This embodiment also provides a method for manufacturing the heat dissipation and electromagnetic shielding packaging structure, including the following steps:

[0057] refer to Figure 3 , providing a substrate 100, wherein a through silicon via is prepared in the substrate;

[0058] refer to Figure 4 , connecting the plurality of chips 200 to the upper surface of the substrate through micro pads, and performing bottom filling between the substrate and the chips;

[0059] refer to Figure 5 , plastic-encapsulating the chips on the substrate so that the formed plastic encapsulation body 300 covers all the chips, grinding and thinning the plastic encapsulation body, and then performing plasma treatment on the surface of the plastic encapsulation body;

[0060] refer to Figure 6, grinding the lower surface of the substrate to form a pad, and preparing a redistribution layer 600 and solder balls 700 on the lower surface thereof;

[0061] refer to Figure 7 , mounting the substrate on a carrier 800 coated with a peeling layer, and then cutting it into individual package structures, each package structure being in the shape of a trapezoidal column;

[0062] refer to Figure 8 A high thermal conductivity interface material is coated on the top surface and four side surfaces of the cut single package structure (i.e., its plastic package body), and after solidification, a high thermal conductivity interface layer 400 is formed. The thickness of the high thermal conductivity interface layer shown is 50 μm. Then, a laser etching process is used to etch rectangular grooves 410 on the surface (top surface and four side surfaces) of the high thermal conductivity interface layer, thereby forming a high thermal conductivity interface layer with a grid structure;

[0063] refer to Figure 9 , the high thermal conductivity interface layer of the grid structure is plasma cleaned, and then titanium is sputtered on the surface of the high thermal conductivity interface layer to form a high adhesion thin layer. The thickness of the high adhesion thin layer is 50nm to ensure full coverage of the grooves. Then a thick layer of copper is electroplated to thicken it to ensure uniform coverage of the metal shielding layer 500. The thickness of the metal shielding layer 500 is 20μm.

[0064] Example 3

[0065] This embodiment provides a heat dissipation and electromagnetic shielding packaging structure, which is different from the second embodiment only in that: Figure 11 As shown, the high thermal conductivity interface layer has a grid structure, and the surface of the high thermal conductivity interface layer is evenly distributed with multiple rectangular grooves. The top and bottom surfaces of the rectangular grooves are both rectangular, and the four side walls are arranged obliquely. The angle between the side wall of the rectangular groove and its top surface is 80°.

[0066] Example 4

[0067] This embodiment provides a packaging structure for heat dissipation and electromagnetic shielding. Compared with Example 2, the only difference is that the high thermal conductivity interface layer has a grid structure, and the surface of the high thermal conductivity interface layer is evenly distributed with multiple hexagonal honeycomb grooves, and the angle between the side wall and the top surface of the hexagonal honeycomb groove is 90°.

[0068] Example 5

[0069] This embodiment provides a packaging structure for heat dissipation and electromagnetic shielding. Compared with Example 2, the only difference is that the high thermal conductivity interface layer is made of a high thermal conductivity interface material, and the high thermal conductivity interface material includes 35wt% silicone resin, 55wt% boron nitride particles, 5wt% diamond powder and 5wt% silane coupling agent.

[0070] Example 6

[0071] This embodiment provides a packaging structure for heat dissipation and electromagnetic shielding. Compared with Example 2, the only difference is that the high thermal conductivity interface layer is made of a high thermal conductivity interface material, and the high thermal conductivity interface material includes 40wt% epoxy resin, 40wt% boron nitride particles, and 20wt% graphene nanosheets.

[0072] Example 7

[0073] This embodiment provides a heat dissipation and electromagnetic shielding packaging structure. Compared with the second embodiment, the only difference is that:

[0074] An ultra-thin inert protective film is formed on the outer surface of the metal shielding layer by sputtering to extend the service life. The ultra-thin inert protective film is selected from aluminum oxide.

[0075] In summary, the present invention sets a high thermal conductivity interface layer with a thermal conductivity between the metal shielding layer and the plastic package, so that the layer acts as a thermal bridge to quickly diffuse the heat generated by the chip to the metal shielding layer, significantly reducing the thermal resistance between the plastic package and the shielding layer. At the same time, the high thermal conductivity interface layer acts as a buffer layer, which can reduce the interface stress under thermal cycling and avoid delamination and microcracks of the metal shielding layer, thereby ensuring electromagnetic shielding effectiveness and mechanical reliability. The high thermal conductivity interface layer with a grid structure can increase the heat dissipation area, optimize the heat dissipation path, and thus improve the thermal conductivity efficiency and heat dissipation performance; and the grid grooves provide three-dimensional anchor points for the metal shielding layer when it is sputtered or electroplated, and increase the contact area. After the metal is sputtered, it is embedded in the grid grooves, reducing the risk of interface delamination and avoiding the discontinuity of the metal layer caused by insufficient surface roughness of the plastic package. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial utilization value.

[0076] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for manufacturing a heat dissipation and electromagnetic shielding packaging structure, the heat dissipation and electromagnetic shielding packaging structure comprising a substrate, a chip, a plastic package, a high thermal conductivity interface layer, and a metal shielding layer, wherein a plurality of chips are flip-chip mounted on the upper surface of the substrate, the plastic package covers the substrate and covers all the chips, the high thermal conductivity interface layer covers the top and side surfaces of the plastic package, the metal shielding layer covers the outer surface of the high thermal conductivity interface layer, and the thermal conductivity of the high thermal conductivity interface layer is greater than the thermal conductivity of the plastic package; It is characterized by: The steps include: (1) Providing a substrate with through-silicon vias, connecting several chips to the upper surface of the substrate through micro-pads, and performing bottom filling between the substrate and the chips; (2) Plastic encapsulating the chips on the substrate so that the formed plastic encapsulation body covers all the chips, and then grinding and thinning the plastic encapsulation body; (3) Grinding the lower surface of the substrate to form a solder pad, and preparing a redistribution layer and solder balls on the lower surface; (4) Mounting the substrate on a carrier coated with a peeling layer, and then cutting it into individual package structures; (5) Coating a high thermal conductivity interface material on the top surface and side surface of the plastic package of a single packaging structure, and forming a high thermal conductivity interface layer after solidification, and etching grooves on the surface of the high thermal conductivity interface layer using a laser etching process to form a high thermal conductivity interface layer with a grid structure; (6) Plasma cleaning is performed on the high thermal conductivity interface layer of the grid structure, and then a metal shielding layer is formed on the surface of the high thermal conductivity interface layer by sputtering and / or electroplating.

2. The production method according to claim 1, characterized in that In step (4), the single package structure is cut into trapezoidal columnar structures or tapered columnar structures.

3. The production method according to claim 1, characterized in that In step (6), a stepped metal deposition process is used to deposit a metal shielding layer on the high thermal conductivity interface layer of the grid structure, specifically comprising the following steps: first, a high-adhesion thin layer is sputtered on the surface of the high thermal conductivity interface layer to ensure full coverage of the grooves, and then a thick layer is sputtered or electroplated for thickening.

4. The production method according to claim 1, characterized in that The high thermal conductivity interface layer is made of a high thermal conductivity interface material. The high thermal conductivity interface material includes a matrix, a filler and other additives. The filler includes a high thermal conductivity electrically conductive filler and / or a high thermal conductivity non-conductive filler.

5. The production method according to claim 4, characterized in that: The matrix is ​​selected from epoxy resin, silicone resin or polyimide; the high thermal conductivity and conductive filler is selected from at least one of silver powder, copper powder, graphene, carbon nanotubes, and silicon carbide; the high thermal conductivity and non-conductive filler is selected from at least one of aluminum nitride, boron nitride, diamond or bismuth telluride.

6. The production method according to claim 1, characterized in that: The width of the groove is between 10 and 30 μm, the depth of the groove is between 10 and 20 μm, and the spacing between the grooves is between 20 and 50 μm.

7. The production method according to claim 1, characterized in that: The aspect ratio of the groove is ≤1:

1.

8. The production method according to claim 1, characterized in that: The sidewall inclination angle of the groove is 60-90°.

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