TWI846241B - High thermal conductive metal substrate and preparation method thereof - Google Patents

Abstract

Provided is a high thermal conductive metal substrate, including: a first thermal conductive adhesive layer with a thickness of 5 to 100 microns; an insulating layer formed on the first thermal conductive adhesive layer and having a thickness of 1 to 150 microns; a second thermal conductive adhesive layer formed on the insulating layer and having a thickness of 5 to 100 microns, so that the insulating layer is between the first thermal conductive adhesive layer and the second thermal conductive adhesive layer; and a copper foil layer formed on the second thermal conductive adhesive layer and having a thickness of 1 to 105 microns, so that the second thermal conductive adhesive layer is between the insulating layer and the copper foil layer, wherein the insulating layer includes 50 to 95 wt% of a resin with imide structures in the polymer backbone, 0 to 25 wt% of an epoxy resin, 0 to 20 wt% of an inorganic filler and 0 to 10 wt% of a catalyst, based on the total weight of the solid content of the insulating layer.

Description

High thermal conductivity metal substrate and preparation method thereof

The present invention relates to a metal substrate with a coated high thermal conductivity film, and more particularly to a high thermal conductivity metal substrate with high heat dissipation efficiency and a method for manufacturing the same.

In the past, heat dissipation materials needed to consider insulation properties, so they needed to achieve a thermal conductivity of 2w/(m*k) and a destruction voltage of 7 to 10(kV). The thickness of the glue used to bond the copper foil layer needed to reach 120 to 150 μm or even higher values to meet the insulation requirements, resulting in a large total thickness of the product. Insufficient thickness will result in unsatisfactory heat dissipation and insulation effects. In addition, the heat dissipation model using TPI (thermoplastic polyimide) doped with heat dissipation powder can reduce the product thickness to a certain extent and meet the insulation requirements, but because TPI processing requires high-temperature operation, the temperature is greater than 350℃, so the processing cost is high and it cannot be effectively mass-produced. If the stretching method is used to prepare polyimide film, the insulation properties can be met, but the product thickness is high and the thermal resistance is high, which means that a sufficiently thick thermal conductive adhesive layer is still required to ensure the heat dissipation performance. In order to reduce the film thickness and improve the thermal resistance, polyimide film manufacturers adopt a thin thickness design. However, when the thin thickness design is 5 to 7.5μm, its mechanical strength is poor, it is too thin and the processing operation is difficult during downstream processing, etc., which cannot meet the requirements of industry standards, and the low manufacturing yield leads to high costs. Therefore, how to develop products with good resistance to voltage penetration, heat dissipation and reduced overall thickness, and produce high thermal conductivity metal substrates through a simplified process, has become an issue that needs to be solved urgently.

In order to solve the above technical problems, the present invention provides a high thermal conductivity metal substrate, which includes: a first thermally conductive adhesive layer with a thickness of 5 to 100 microns; an insulating layer formed on the first thermally conductive adhesive layer and with a thickness of 1 to 150 microns; a second thermally conductive adhesive layer formed on the insulating layer and with a thickness of 5 to 100 microns, so that the insulating layer is located between the first thermally conductive adhesive layer and the second thermally conductive adhesive layer; and a second thermally conductive adhesive layer formed on the insulating layer. A copper foil layer with a thickness of 1 to 105 microns is formed on the second thermally conductive adhesive layer, so that the second thermally conductive adhesive layer is located between the insulating layer and the copper foil layer, wherein, based on the total weight of the solid content of the insulating layer, the insulating layer comprises: 50 to 95 wt% of a resin having an imide structure in the polymer main chain; 0 to 25 wt% of an epoxy resin; 0 to 20 wt% of an inorganic filler; and 0 to 10 wt% of a catalyst.

In a specific embodiment, the high thermal conductivity metal substrate further includes a third thermal conductive adhesive layer with a thickness of 5 to 100 microns, which is formed between the insulating layer and the second thermal conductive adhesive layer.

In a specific embodiment, the resin having an imide structure in the polymer main chain of the high thermal conductivity metal substrate includes a polyimide resin or a polyamide imide resin.

In a specific implementation, the polyimide resin of the high thermal conductivity metal substrate is obtained by polymerizing monomers containing diamine and acid anhydride, and the polyamide imide resin is obtained by polymerizing monomers containing the diamine, the acid anhydride and an isocyanate compound.

In a specific embodiment, the diamine is selected from 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)diaminobenzene (TFMB), 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenyl ether, bis[4-(3-aminophenoxy)phenyl]sulfonamide, bis[4-(4-aminophenoxy)phenyl]sulfonamide, 2, At least one of the group consisting of 2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, bis[4-(4-aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4- (4-aminophenoxy)phenyl 1-ethyl ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4-aminophenoxy)benzene and 1,4-bis(4-aminophenoxy)benzene.

In a specific embodiment, the acid anhydride is selected from at least one of the group consisting of hexafluorodianhydride (6FDA), bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,2-ethylenebis[1,3-dihydro-1,3-dioxoisobenzofuran-5-carboxylate], 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, trimellitic anhydride (TMA) and cis-abiotic anhydride.

In a specific embodiment, the isocyanate compound is selected from at least one of the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, naphthalene-1,5-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate.

In a specific embodiment, the molar ratio of the diamine to the anhydride in the polyamide imide resin is 1:2.05 to 1:2.20.

In a specific embodiment, in the polyimide resin, the molar ratio of the diamine to the anhydride is 1:0.90 to 1:1.10.

In a specific embodiment, the molar ratio of the diamine to the isocyanate in the polyamide imide resin is 1:1.05 to 1:1.50.

In a specific embodiment, the epoxy resin is at least one selected from the group consisting of glycidylamine epoxy resin, glycidyl ester epoxy resin, epoxide alkylene compound, alicyclic epoxy resin, polyphenol glycidyl ether epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, aliphatic glycidyl ether epoxy resin, heterocyclic epoxy resin and mixed epoxy resin.

In a specific embodiment, the catalyst is at least one selected from the group consisting of 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole and 1-benzyl-2-phenylimidazole.

In a specific embodiment, the inorganic filler is at least one selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, quartz powder and clay.

In a specific embodiment, the inorganic filler is a powder with a particle size of 0.5 microns to 10 microns.

In a specific embodiment, the material forming each of the first thermally conductive adhesive layer, the second thermally conductive adhesive layer and the third thermally conductive adhesive layer includes a resin material and 10 to 75 wt% of thermally conductive powder, and the resin material of each of the first thermally conductive adhesive layer, the second thermally conductive adhesive layer and the third thermally conductive adhesive layer is independently selected from at least one of the group consisting of epoxy resin, acrylic resin, urethane resin, silicone rubber resin, polyparaxylene resin, dimaleimide resin and polyimide resin.

In a specific embodiment, the thermally conductive powder is independently selected from at least one of the group consisting of zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, graphite and graphene.

In a specific embodiment, the content of the thermally conductive powder in the high thermally conductive metal substrate is 10 to 75 wt%.

In a specific embodiment, the surface roughness (Rz) of the copper foil layer is 0.4 to 4.0 microns, and electrolytic copper foil or rolled copper foil can be used.

In a specific embodiment, the high thermal conductivity metal substrate further includes an aluminum plate strip formed on the first thermal conductive adhesive layer, so that the first thermal conductive adhesive layer is located between the insulating layer and the aluminum plate strip.

The present invention further provides a high thermal conductivity composite film, which includes a carrier layer with a thickness of 12.5 to 250 microns, and an insulating layer and a first thermal conductive adhesive layer sequentially formed on the carrier layer.

In another specific embodiment, the insulating layer of the high thermal conductivity composite film includes a plurality of insulating sub-layers. Thus, the insulating layer of the high thermal conductivity metal substrate of the present invention may also include a plurality of insulating sub-layers.

In a specific embodiment, the carrier layer of the high thermal conductivity composite film is selected from at least one of the group consisting of polypropylene, biaxially oriented polypropylene, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyurethane and polyamide.

The present invention further provides a method for preparing a high thermal conductivity metal substrate, comprising: coating a varnish layer on a carrier layer, wherein the varnish layer comprises, based on the total weight of the solid content of the varnish layer, 50 to 95 wt% of a resin having an imide structure in the polymer main chain; 0 to 25 wt% of an epoxy resin; 0 to 20 wt% of an inorganic filler; and 0 to 10 wt% of a catalyst; and heating the substrate to a temperature range of 5 The varnish layer is cured at 0 to 180°C to obtain an insulating layer; a first thermally conductive adhesive layer is coated on the insulating layer; the carrier layer is removed from the insulating layer to expose the surface of the insulating layer; and a backing copper foil is pressed on the surface of the insulating layer, wherein the backing copper foil includes a copper foil layer and a second thermally conductive adhesive layer formed on the copper foil layer, and the second thermally conductive adhesive layer is located between the insulating layer and the copper foil layer.

In one specific embodiment, the steps of applying a varnish layer and curing can be repeated to form an insulating layer having two or more insulating sublayers and a thickness of 1 to 150 microns.

In a specific embodiment, the method for preparing a high thermal conductivity metal substrate further includes forming a third thermally conductive adhesive layer on the exposed surface of the insulating layer before pressing the backing copper foil, and then pressing the backing copper foil on the third thermally conductive adhesive layer.

In a specific implementation, the method for preparing a high thermal conductivity metal substrate further includes forming a third thermally conductive adhesive layer on the copper foil layer before pressing the backing copper foil, and then pressing the backing copper foil onto the surface of the insulating layer by the third thermally conductive adhesive layer.

In a specific embodiment, the method for preparing the high thermal conductivity metal substrate is to press the backing copper foil at 100 to 120° C., preferably 110° C., and a pressure of 1 to 3 kgf/cm ² , preferably 2 kgf/cm ² .

In a specific embodiment, the method for preparing a high thermal conductivity metal substrate further includes pressing an aluminum plate strip on the first thermally conductive adhesive layer.

The present invention further provides a method for preparing a high thermal conductivity metal substrate, comprising: coating a varnish layer on a carrier layer, wherein the varnish layer comprises, based on the total weight of the solid content of the varnish layer, 50 to 95 wt% of a resin having an imide structure in the polymer main chain; 0 to 25 wt% of an epoxy resin; 0 to 20 wt% of an inorganic filler; and 0 to 10 wt% of a catalyst; heating the substrate at a temperature range of 50 to 180 ℃, curing the varnish layer to obtain an insulating layer; coating the insulating layer to form a first thermally conductive adhesive layer; removing the carrier layer from the insulating layer to expose the surface of the insulating layer; attaching a second thermally conductive adhesive layer to the surface of the insulating layer; attaching a copper foil layer and an aluminum strip to the second thermally conductive adhesive layer and the first thermally conductive adhesive layer respectively; and pressing the insulating layer, the first thermally conductive adhesive layer, the second thermally conductive adhesive layer, the copper foil layer and the aluminum strip. According to the present invention, the high thermal conductivity metal substrate has at least the following advantages:

1. Use the carrier layer to produce the film, add inorganic fillers to the insulating layer, so that the surface energy and roughness of the carrier layer and the insulating layer are designed to match without using a release agent on the carrier layer. The high surface energy of the insulating layer is easy to use in the bonding and coating process, and there is no need to use additional surface treatment processes such as corona.

Second, the insulating layer can be composed of multiple layers of coating, which is easy to take into account various characteristics and can match the downstream processing requirements.

3. The carrier layer is coated with varnish, which is cheaper than the film produced by the cast film process. After the insulating layer or high thermal conductivity composite film is made, it can be rolled up for standby use. The ultra-thin insulating layer does not need to be prepared separately in the downstream process to avoid tearing, etc., making it easier to operate and process.

4. Compared with the film produced by the cast film process, the varnish type insulation layer has better dimensional stability because there is no residual stress from the stretching process.

5. Thin design, easy to produce various thicknesses, can replace the high-priced thin polyimide (PI) on the market, with a thickness of less than 12.5 microns, preferably 5 to 8 microns.

6. The product width can be more flexible when coated with a carrier layer. The production width of PET, PEN and other film materials used as the carrier layer is much larger than that of biaxially oriented polyimide film (1500 to 2000mm), so it can be produced with multiple widths and still have a high utilization rate.

7. With good heat dissipation and insulation properties, this coating film can be used in thermal conductive backing copper foil RCC (Resin Coating Copper) to achieve the target thermal resistance and destruction voltage at a thinner thickness, greatly reducing the cost of raw materials.

8. It has the characteristics of continuous large-scale production, which can effectively reduce production costs, significantly improve yield and efficiency, and enhance product competitiveness.

100: Carrier layer

200: Insulation layer

200a,200b: insulating sublayer

300: First thermal conductive adhesive layer

400: Copper foil layer

500: Second thermal conductive adhesive layer

700: The third thermal conductive adhesive layer

800: Aluminum strip

The implementation method of the present invention is described through exemplary reference drawings:

FIG1A is a schematic diagram showing a method for preparing the high thermal conductivity composite film of the present invention, which is used to prepare the first embodiment of the high thermal conductivity metal substrate of the present invention;

Figure 2 is a schematic diagram showing the backing copper foil being pressed onto the surface of the insulating layer;

Figure 3 is a schematic diagram of the structure of the first embodiment of the high thermal conductivity metal substrate of the present invention;

FIG. 4A is a schematic diagram of the manufacturing method of the second embodiment of the high thermal conductivity metal substrate of the present invention; FIG. 4B is a schematic diagram of the manufacturing method of the second embodiment of the high thermal conductivity metal substrate of the present invention;

FIG5 is a schematic diagram of the structure of the second embodiment of the high thermal conductivity metal substrate of the present invention;

FIG6 is a schematic diagram of the structure of the third embodiment of the high thermal conductivity metal substrate of the present invention; and

Figure 7 is a schematic diagram of the structure of the fourth embodiment of the high thermal conductivity metal substrate of the present invention.

The following is a specific and concrete example to illustrate the implementation of the present invention. People familiar with this art can easily understand the advantages and effects of the present invention from the content disclosed in this manual.

It should be understood that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the contents disclosed in the specification for understanding and reading by people familiar with this technology, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be produced by the present invention. At the same time, the references such as "one", "upper" and "lower" in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content. Furthermore, all ranges and values herein are inclusive and combinable. Any value or point within the range described in this article, such as any integer, can be used as the minimum or maximum value to derive the lower range, etc.

As shown in FIG. 1A, 1B to FIG. 3, the present invention provides a method for preparing a high thermal conductivity metal substrate, which includes: coating a varnish layer on a carrier layer 100, wherein the varnish layer comprises 50 to 95 wt% of a resin having an acylimide structure in a polymer main chain, 0 to 25 wt% of an epoxy resin, 0 to 20 wt% of an inorganic filler, and 0 to 10 wt% of a catalyst, based on the total weight of the solid content of the varnish layer; curing the varnish layer at a temperature range of 50 to 180°C to obtain an insulating layer 200; and then coating the insulating layer 200 to form a first thermally conductive adhesive layer 300. Here, as shown in FIG. 1A , the present invention provides a high thermal conductivity composite film for preparing a high thermal conductivity metal substrate, the high thermal conductivity composite film comprising: a carrier layer 100 having a thickness of 12.5 to 250 microns; and an insulating layer 200 and a first thermal conductive adhesive layer 300 sequentially formed on the carrier layer 100.

In a specific embodiment, the carrier layer 100 is selected from at least one of the group consisting of polypropylene, biaxially oriented polypropylene, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyurethane and polyamide.

In another specific embodiment, as shown in FIG. 1B , the insulating layer 200 includes a plurality of insulating sublayers 200a, 200b. In a specific embodiment, the steps of applying a varnish layer and curing can be repeated to form an insulating layer having two or more insulating sublayers and a thickness of 1 to 150 microns. Similarly, the insulating layer of the high thermal conductivity composite film can also include a plurality of insulating sublayers.

As shown in FIG. 2 , the carrier layer 100 is removed from the insulating layer 200 to expose the surface of the insulating layer 100, and then the backing copper foil is pressed on the surface of the insulating layer 200 at, for example, 100 to 120° C. and a pressure of 1 to 3 kgf/cm ^2. The backing copper foil includes a copper foil layer 400 and a second thermally conductive adhesive layer 500 formed on the copper foil layer 400.

As shown in FIG3 , the second thermally conductive adhesive layer 500 is located between the insulating layer 200 and the copper foil layer 400 to obtain the high thermally conductive metal substrate of the present invention. Based on this, the high thermally conductive metal substrate includes: a first thermally conductive adhesive layer 300 with a thickness of 5 to 100 microns; an insulating layer 200 formed on the first thermally conductive adhesive layer 300 and with a thickness of 1 to 150 microns; a second thermally conductive adhesive layer 500 formed on the insulating layer 200 and with a thickness of 5 to 100 microns, so that the insulating layer 200 is located between the first thermally conductive adhesive layer 300 and the second thermally conductive adhesive layer 500; and a second thermally conductive adhesive layer formed on the second thermally conductive adhesive layer 300. The copper foil layer 400 with a thickness of 1 to 105 microns is disposed on the insulating layer 200, so that the second thermally conductive adhesive layer 500 is located between the insulating layer 200 and the copper foil layer 400, wherein, based on the total weight of the solid content of the insulating layer 200, the insulating layer 200 comprises: 50 to 95 wt% of a resin having an imide structure in the polymer main chain; 0 to 25 wt% of an epoxy resin; 0 to 20 wt% of an inorganic filler; and 0 to 10 wt% of a catalyst.

In some specific embodiments, the thickness of the first thermally conductive adhesive layer may be 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 65, 70, 75, 80, 85, 90, 95 or 100 microns.

In some specific embodiments, the thickness of the insulating layer may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140 or 150 microns.

In some specific embodiments, the thickness of the second thermally conductive adhesive layer may be 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 65, 70, 75, 80, 85, 90, 95 or 100 microns.

In some embodiments, the copper foil layer may have a thickness of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 65, 70, 75, 80, 85, 90, 95, 100 or 105 microns.

In some specific embodiments, the content of the resin having an imide structure in the polymer main chain in the insulating layer may be 50, 55, 60, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 90 or 95 wt%.

In some specific embodiments, the content of the epoxy resin in the insulating layer may be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20 or 25 wt%.

In some specific embodiments, the content of the inorganic filler in the insulating layer may be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15 or 20 wt%.

In some specific embodiments, the content of the catalyst in the insulating layer may be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 wt%.

In a specific embodiment, the resin having an imide structure in the polymer main chain of the high thermal conductivity metal substrate includes a polyimide resin or a polyamide imide resin.

In a specific implementation, the polyimide resin of the high thermal conductivity metal substrate is obtained by polymerizing monomers containing diamine and acid anhydride, and the polyamide imide resin is obtained by polymerizing monomers containing the diamine, the acid anhydride and an isocyanate compound.

In a specific embodiment, the diamine is selected from 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)diaminobenzene (TFMB), 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenyl ether, bis[4-(3-aminophenoxy)phenyl]sulfonamide, bis[4-(4-aminophenoxy)phenyl]sulfonamide, 2, At least one of the group consisting of 2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, bis[4-(4-aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ethyl ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4-aminophenoxy)benzene and 1,4-bis(4-aminophenoxy)benzene.

In a specific embodiment, the acid anhydride is at least one selected from the group consisting of hexafluorodianhydride (6FDA), bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,2-ethylenebis[1,3-dihydro-1,3-dioxoisobenzofuran-5-carboxylate], 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, trimellitic anhydride (TMA) and cis-abiotic anhydride.

In a specific embodiment, the isocyanate compound is selected from at least one of the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, naphthalene-1,5-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate.

In a specific embodiment, in the polyamide imide resin, the molar ratio of the diamine to the anhydride is 1:2.05 to 1:2.20. For example, 1:2.05, 1:2.06, 1:2.07, 1:2.08, 1:2.09, 1:2.1, 1:2.15 or 1:2.2.

In a specific embodiment, in the polyimide resin, the molar ratio of the diamine to the anhydride is 1:0.90 to 1:1.10. For example, 1:0.90, 1:1.0 or 1:1.0.

In a specific embodiment, in the polyamide imide resin, the molar ratio of the diamine to the isocyanate is 1:1.05 to 1:1.50. For example, 1:1.05, 1:1.1, 1:1.15, 1:1.2, 1:1.25, 1:1.3, 1:1.35, 1:1.4, 1:1.45 or 1:1.5.

In a specific embodiment, the epoxy resin is at least one selected from the group consisting of glycidylamine epoxy resin, glycidyl ester epoxy resin, epoxide alkylene compound, alicyclic epoxy resin, polyphenol glycidyl ether epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, aliphatic glycidyl ether epoxy resin, heterocyclic epoxy resin and mixed epoxy resin.

In a specific embodiment, the catalyst is at least one selected from the group consisting of 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole and 1-benzyl-2-phenylimidazole.

In a specific embodiment, the inorganic filler is at least one selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, quartz powder and clay.

In a specific embodiment, the inorganic filler is a powder with a particle size of 0.5 microns to 10 microns. For example, the particle size is 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 microns.

In the second embodiment of the high thermal conductivity metal substrate of the present invention, as shown in Figures 4A and 5, the preparation method of the high thermal conductivity metal substrate further includes forming a third thermally conductive adhesive layer 700 on the exposed surface of the insulating layer 200 before pressing the backing copper foil, and then pressing the backing copper foil on the third thermally conductive adhesive layer 700 at, for example, 100 to 120°C and a pressure of 1 to 3 kgf/ ^cm2 , so that the high thermal conductivity metal substrate further includes a third thermally conductive adhesive layer 700 with a thickness of 5 to 100 microns, which is formed between the insulating layer 200 and the second thermally conductive adhesive layer 500.

In the implementation mode of the high thermal conductivity metal substrate shown in FIG. 5 of the present invention, a third thermally conductive adhesive layer 700 can be formed on the copper foil layer 400 before the backing copper foil is pressed with reference to the method shown in FIG. 4B , and then the backing copper foil is pressed onto the surface of the insulating layer 200 by the third thermally conductive adhesive layer 700 at, for example, 100 to 120° C. and a pressure of 1 to 3 kgf/cm ² , so that the high thermally conductive metal substrate further includes a third thermally conductive adhesive layer 700 with a thickness of 5 to 100 microns, which is formed between the insulating layer 200 and the second thermally conductive adhesive layer 500.

In a specific embodiment, the material forming each of the first thermally conductive adhesive layer 300, the second thermally conductive adhesive layer 500 and the third thermally conductive adhesive layer 700 includes a resin material and 10 to 75 wt % of a thermally conductive powder, and the resin material of each of the first thermally conductive adhesive layer 300, the second thermally conductive adhesive layer 500 and the third thermally conductive adhesive layer 700 is independently selected from epoxy resin. , acrylic resin, urethane resin, silicone rubber resin, polyparaxylene resin, dimaleimide resin and polyimide resin, and the thermal conductive powder is independently selected from at least one of the group consisting of zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, graphite and graphene.

Preferably, the content of the thermally conductive powder is 10 to 75wt%. For example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70 or 75wt%.

In the third embodiment of the high thermal conductivity metal substrate of the present invention, an aluminum plate strip 800 is pressed onto the first thermal conductive adhesive layer 300 of the high thermal conductivity metal substrate shown in FIG. 3 .

Referring again to the fourth embodiment shown in FIG. 7 , the aluminum plate strip 800 may also be pressed onto the first thermally conductive adhesive layer 300 of the high thermally conductive metal substrate without the third thermally conductive adhesive layer 700. In addition, the present invention also provides another method for preparing the high thermally conductive metal substrate of the fourth embodiment, which includes applying a varnish layer on the carrier layer 100, wherein the varnish layer comprises, based on the total weight of the solid content of the varnish layer, 50 to 95 wt% of a resin having an imide structure in the polymer main chain; 0 to 25 wt% of an epoxy resin; 0 to 20 wt% of an inorganic filler; and 0 to 10 wt% of a catalyst; curing the varnish layer at a temperature range of 50 to 180° C. The invention relates to a method for forming a heat conductive adhesive layer 300 by coating the heat conductive adhesive layer 300 on the heat conductive adhesive layer 200; removing the carrier layer 100 from the heat conductive adhesive layer 200 to expose the surface of the heat conductive adhesive layer 200; laminating the heat conductive adhesive layer 500 on the surface of the heat conductive adhesive layer 200; laminating the copper foil layer 400 and the aluminum plate strip 800 on the heat conductive adhesive layer 500 and the first heat conductive adhesive layer 300 respectively; and performing the heat conductive adhesive layer 300 under a temperature of 175°C and a pressure of 40 kgf/cm ² The insulating layer 200, the first thermally conductive adhesive layer 300, the second thermally conductive adhesive layer 500, the copper foil layer 400 and the aluminum plate tape 800 are pressed together at the same time.

Test method

For the test methods of thermal conductivity and thermal resistance, please refer to ASTM D5470.

The test methods for breaking voltage and dielectric strength refer to ASTM D149.

The dimensional stability test refers to IPC-TM-650 2.2.4C.

The measurement of tensile strength, elastic modulus, and elongation shall comply with IPC-TM-650 2.4.19.

Release force test is in accordance with ASTM D3330.

[Example]

Example 1 Synthesis of polyamide imide

First, add 4.11g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) to 33g of N-methylpyrrolidone (NMP), introduce nitrogen, and stir at 80°C to dissolve. Then add 4.03g of trimellitic anhydride (TMA) and react at 80°C for 1 hour. After adding toluene, heat up to 170°C to evaporate the water, and finally heat up to 190°C to remove toluene. After returning to room temperature, add 3.00g of 4,4'-diphenylmethane diisocyanate (MDI) and 0.13g of triethylamine (Et ₃ N), heat up to 120°C and react for 3 hours to complete the solution of soluble polyamide imide.

Example 2 Synthesis of polyimide

Under nitrogen, add monomers to 349g NMP at 80℃ in sequence, first add 32.02g 2,2'-bis(trifluoromethyl)diaminobiphenyl (TFMB), then add 21.99g hexafluorodianhydride (6FDA) and 12.41g bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (B1317). Add 6FDA and B1317 in equal proportions, the additional amount is 5% of the added amount. Raise the temperature to 150℃ and add 0.80g N-ethylpiperidine. Raise the temperature to 190℃ and react for 4 hours to obtain a soluble polyimide solution.

The varnish layer shown in Table 1 uses PET as a carrier (Dupont Teijin Films, YG0). The varnish layer is coated on the carrier layer and cured at a low temperature of 50 to 180°C to form an insulating layer, thereby obtaining a laminated coating type insulating layer film as shown in FIG. 1 and making corresponding embodiment and comparative example characteristic data, wherein the respective composition ratios of polyimide and polyamide imide can refer to the above-mentioned synthesis steps. The epoxy resin used was dicyclopentadiene phenolic epoxy resin (DCPD, Nan Ya, EH272H), the catalyst was 2-ethyl-4-methylimidazole (Shikoku Chemical, Japan, 2E4MZ-CN), and the inorganic filler was SiO ₂ (D50=0.93 μm ) (Yadum, P30-C1).

Table 1

The results in Table 2 show that the coating-type insulating film of the present invention has a reasonable ratio, and the results show that the film has a balanced thermal conductivity and insulation performance and is easy to release. The mechanical properties, electrical properties, thermal properties, dimensional stability, etc. are all tested after removing the carrier layer.

Table 2

In addition, the varnish layer ratio of Example 2 in Table 1 can also be used as the second polyimide varnish layer. In combination with other embodiments in Table 1, such as using the varnish layer ratio of Example 1 as the first polyimide varnish layer in Table 3, the coating-type insulating layer film properties of Examples 7 to 10 in Table 3 below are obtained. As shown in Table 3 below, the mechanical properties and dielectric strength of the obtained insulating layer film are significantly improved.

table 3

Example 3 Insulation properties of coated polyimide film

Example 6 in Table 1 is matched with a PET carrier (Dupont Teijin Films, YG0), and a polyimide varnish layer is coated on the carrier layer, and low-temperature curing is performed at 50 to 180°C to obtain a coated polyimide film. After removing the carrier layer, the corresponding examples A1 to A3 are made and compared with commercially available black and yellow polyimide films. Comparative examples B1 to B6 are PIAM GF050 (yellow), PIAM GF030 (yellow), Dupont 20EN (yellow), Dupont 35KBC (black), Damai BK012 (black), and TL012 (yellow). The relative destruction voltages of these examples and comparative examples are compared to obtain Table 4.

From Table 4, it can be seen that the dielectric strength of the coated polyimide film of the present invention can reach the level of commercially available yellow polyimide film, which is far superior to commercially available black polyimide film. In addition to being able to correspond to the existing film thickness specifications, it can also be easily prepared to a thinner thickness, such as 1 to 5 microns.

Example 4: Comparison of properties of high thermal conductivity metal substrates

The coated polyimide films of Examples A1 and A2 in Table 4 were used as the 5-micron and 8-micron insulating layers in the examples to obtain Examples C1 to C4. At the same time, Comparative Examples D1 and D2 used the commercially available polyimide films of Comparative Examples B6 and B4 to make thermally conductive metal substrates, respectively. Comparative Examples D3 and D4 used thermally conductive metal substrates with copper thermally conductive adhesive layers to make the thermally conductive metal substrate property comparison in Table 5. The copper foil layer used in the examples and comparative examples was 35 microns ( μm ) of Futian CF-TGFB-HTE, and the thermally conductive adhesive layer used was 30% acrylic resin (BAP-01) containing 70% boron nitride (D50=2.78 microns). Except for C1, which is slightly insufficient in terms of the breaking voltage, the structures C2 to C4 in Table 5 can obtain technical characteristic indicators that can make the thermal conductivity close to 3w/(m*k) and the breaking voltage reach 7 to 10KV. At the same time, the varnish-type insulation layer is directly generated on the carrier layer in the thin film scene, which is easier to process in the downstream process. From the comparison of examples D1 and D2, it can be found that the polyimide film used for the thermal conductive metal substrate still has deficiencies in terms of thermal conductivity or breaking voltage. Comparative Example D3 still has insufficient breaking voltage, while Comparative Example D4 shows that the total thickness needs to be 185 microns to reach the technical indicators of thermal conductivity 3w/(m*k) and breaking voltage 7KV, but Examples C3 and C4 can obtain higher breaking voltages with comparable thermal conductivity.

The above embodiments are only illustrative and not intended to limit the present invention. Anyone familiar with this technology may modify and change the above embodiments without violating the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is defined by the scope of the patent application attached to the present invention. As long as it does not affect the effect and implementation purpose of the present invention, it should be covered by this public technical content.

200: Insulation layer

300: First thermal conductive adhesive layer

400: Copper foil layer

500: Second thermal conductive adhesive layer

Claims (25)

A high thermal conductivity metal substrate comprises: a first thermal conductive adhesive layer with a thickness of 5 to 100 microns; an insulating layer formed on the first thermal conductive adhesive layer and with a thickness of 1 to 150 microns; a second thermal conductive adhesive layer formed on the insulating layer and with a thickness of 5 to 100 microns, wherein the insulating layer is located between the first thermal conductive adhesive layer and the second thermal conductive adhesive layer. and a copper foil layer formed on the second thermally conductive adhesive layer and having a thickness of 1 to 105 microns, so that the second thermally conductive adhesive layer is located between the insulating layer and the copper foil layer, wherein, based on the total weight of the solid content of the insulating layer, the insulating layer comprises: 50 to 95 wt% of a resin having an imide structure in the polymer main chain; 1 to 2 5wt% of epoxy resin; 1 to 20wt% of inorganic filler; and 1 to 10wt% of catalyst, wherein the material of each of the first thermally conductive adhesive layer and the second thermally conductive adhesive layer comprises a resin material and 10 to 75wt% of thermally conductive powder, and the resin material is independently selected from epoxy resin, acrylic resin, urethane The thermal conductive powder is at least one selected from the group consisting of zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, graphite and graphene. A high thermal conductivity metal substrate as described in claim 1, wherein the insulating layer includes a plurality of insulating sub-layers. The high thermal conductivity metal substrate as described in claim 1 further includes a third thermally conductive adhesive layer with a thickness of 5 to 100 microns, which is formed between the insulating layer and the second thermally conductive adhesive layer. The high thermal conductivity metal substrate as described in claim 1, wherein the resin having an imide structure in the polymer main chain includes a polyimide resin or a polyamide imide resin. The high thermal conductivity metal substrate as described in claim 4, wherein the polyimide resin is obtained by polymerizing monomers containing diamine and acid anhydride, and the polyamide imide resin is obtained by polymerizing monomers containing the diamine, the acid anhydride and an isocyanate compound. The high thermal conductivity metal substrate as described in claim 5, wherein the diamine is selected from 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)diaminobenzene (TFMB), 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenyl ether, bis[4-(3-aminophenoxy)phenyl]sulfonamide, bis[4-(4-aminophenoxy)phenyl]sulfonamide, At least one of the group consisting of 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, bis[4-(4-aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ethyl ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4-aminophenoxy)benzene and 1,4-bis(4-aminophenoxy)benzene. A high thermal conductivity metal substrate as described in claim 5, wherein the acid anhydride is at least one selected from the group consisting of hexafluorodianhydride (6FDA), bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,2-ethylenebis[1,3-dihydro-1,3-dioxoisobenzofuran-5-carboxylate], 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, trimellitic anhydride (TMA) and cis-abiotic anhydride. A high thermal conductivity metal substrate as described in claim 5, wherein the isocyanate compound is at least one selected from the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, naphthalene-1,5-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate. A high thermal conductivity metal substrate as described in claim 5, wherein in the polyamide imide resin, the molar ratio of the diamine to the anhydride is 1:2.05 to 1:2.20. A high thermal conductivity metal substrate as described in claim 5, wherein in the polyimide resin, the molar ratio of the diamine to the anhydride is 1:0.90 to 1:1.10. A high thermal conductivity metal substrate as described in claim 5, wherein in the polyamide imide resin, the molar ratio of the diamine to the isocyanate is 1:1.05 to 1:1.50. The high thermal conductivity metal substrate as described in claim 1, wherein the epoxy resin is at least one selected from the group consisting of glycidylamine epoxy resin, glycidyl ester epoxy resin, epoxide alkylene compound, aliphatic epoxy resin, polyphenol glycidyl ether epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, aliphatic glycidyl ether epoxy resin and heterocyclic epoxy resin. A high thermal conductivity metal substrate as described in claim 1, wherein the catalyst is at least one selected from the group consisting of 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole and 1-benzyl-2-phenylimidazole. The high thermal conductivity metal substrate as described in claim 1, wherein the inorganic filler is at least one selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, quartz powder and clay. The high thermal conductivity metal substrate as described in claim 1, wherein the inorganic filler is a powder with a particle size of 0.5 microns to 10 microns. The high thermal conductivity metal substrate as described in claim 3, wherein the material forming the third thermally conductive adhesive layer includes a resin material and 10 to 75 wt% of thermally conductive powder, and the resin material of the third thermally conductive adhesive layer is independently selected from at least one of the group consisting of epoxy resin, acrylic resin, urethane resin, silicone rubber resin, polyparaxylene resin, dimaleimide resin and polyimide resin, and the thermally conductive powder is independently selected from at least one of the group consisting of zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, graphite and graphene. The high thermal conductivity metal substrate as described in claim 1 further includes an aluminum plate strip formed on the first thermally conductive adhesive layer, so that the first thermally conductive adhesive layer is located between the insulating layer and the aluminum plate strip. A high thermal conductivity composite film comprises: a carrier layer with a thickness of 12.5 to 250 microns; and an insulating layer and a first thermally conductive adhesive layer sequentially formed on the carrier layer. The high thermal conductivity composite film as described in claim 19, wherein the carrier layer is selected from at least one of the group consisting of polypropylene, biaxially oriented polypropylene, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyurethane and polyamide. A method for preparing a high thermal conductivity metal substrate comprises: coating a varnish layer on a carrier layer, wherein the varnish layer comprises, based on the total weight of the solid content of the varnish layer, 50 to 95 wt% of a resin having an imide structure in the polymer main chain; 1 to 25 wt% of an epoxy resin; 1 to 20 wt% of an inorganic filler; and 1 to 1 0wt% of catalyst; curing the varnish layer at a temperature range of 50 to 180°C to obtain an insulating layer; coating the insulating layer with a first thermally conductive adhesive layer; removing the carrier layer from the insulating layer to expose the insulating layer surface; and pressing a backing copper foil on the insulating layer surface, the backing copper foil comprising a copper foil layer and a thermal conductive adhesive layer formed on the insulating layer. A second thermally conductive adhesive layer is formed on the copper foil layer, and the second thermally conductive adhesive layer is located between the insulating layer and the copper foil layer, wherein the material of each of the first thermally conductive adhesive layer and the second thermally conductive adhesive layer includes a resin material and 10 to 75 wt% of a thermally conductive powder, and the resin material is independently selected from epoxy resin, acrylic resin, urethane resin, At least one of the group consisting of resin, silicone rubber resin, polyparaxylene resin, dimaleimide resin and polyimide resin, and the thermal conductive powder is independently selected from at least one of the group consisting of zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, graphite and graphene. The method for preparing a high thermal conductivity metal substrate as described in claim 20 further includes forming a third thermally conductive adhesive layer on the exposed surface of the insulating layer before pressing the backing copper foil, and then pressing the backing copper foil on the third thermally conductive adhesive layer. The method for preparing a high thermal conductivity metal substrate as described in claim 20 further includes forming a third thermally conductive adhesive layer on the copper foil layer before pressing the backing copper foil, and then pressing the backing copper foil onto the surface of the insulating layer by the third thermally conductive adhesive layer. The method for preparing a high thermal conductivity metal substrate as described in claim 20 comprises pressing the backing copper foil at 100 to 120°C and a pressure of 1 to 3 kgf/ ^cm2 . The method for preparing a high thermal conductivity metal substrate as described in claim 20 further includes pressing an aluminum plate strip onto the first thermally conductive adhesive layer. A method for preparing a high thermal conductivity metal substrate comprises: Coating a varnish layer on a carrier layer, wherein, based on the total weight of the solid content of the varnish layer, the varnish layer comprises 50 to 95 wt% of a resin having an imide structure in the polymer main chain; 1 to 25 wt% of an epoxy resin; 1 to 20 wt% of an inorganic filler; and 1 to 10 wt% of a t% of a catalyst; curing the varnish layer at a temperature range of 50 to 180° C. to obtain an insulating layer; coating the insulating layer with a first thermally conductive adhesive layer; removing the carrier layer from the insulating layer to expose the surface of the insulating layer; attaching a second thermally conductive adhesive layer to the surface of the insulating layer; attaching a second thermally conductive adhesive layer to the second thermally conductive adhesive layer and the first thermally conductive adhesive layer respectively; The copper foil layer and the aluminum strip are combined; and the insulating layer, the first thermally conductive adhesive layer, the second thermally conductive adhesive layer, the copper foil layer and the aluminum strip are pressed together, wherein the material of each of the first thermally conductive adhesive layer and the second thermally conductive adhesive layer includes a resin material and 10 to 75 wt % of a thermally conductive powder, and the resin material is independently selected from epoxy resin, acrylic resin, urethane resin, At least one of the group consisting of ester resin, silicone rubber resin, polyparaxylene resin, dimaleimide resin and polyimide resin, and the thermal conductive powder is independently selected from at least one of the group consisting of zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder, graphite and graphene.

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