TWI429346B - High thermal conductivity metal substrate and manufacturing method thereof - Google Patents

Description

High thermal conductivity metal substrate and method of manufacturing same

The present invention relates to a metal substrate and a method of manufacturing the same, and more particularly to a highly thermally conductive metal substrate and a method of manufacturing the same.

Conventional printed circuit board structures include a surface metal layer and an insulating layer that can be patterned to form an electrical circuit. As electronic products move toward a lighter and shorter trend, the electronic components on the circuit board become more and more dense, and the heat generated by the electronic components cannot be effectively dissipated, which will reduce the reliability of the components. The conventional printed circuit board has no special heat dissipation design, and its heat dissipation effect cannot meet the demand.

The conventional thermally conductive metal substrate comprises a three-layer laminate structure: an underlying metal layer, a thermally conductive dielectric layer (or a thermally conductive dielectric layer overlying the underlying metal), and a surface metal layer. For example, "The Thermal Conduction Structure of Printed Circuit Board" of the Republic of China Patent No. 430959, "Improvement of the Structure of the Diode Carrier Plate of the Liquid Crystal Display", No. M311865, "Printed Circuit Board of the Light Emitting Diode Carrier" Structural Improvements, "Lighting Modules and Carrier Structures", No. M331757, and "Integrated Heat Dissipation Substrates", No. M338542.

In these prior patents, the surface metal layer is used to trace the circuit for driving the electronic component; and because of the introduction of the underlying metal layer, the heat dissipation effect of the conventional thermally conductive metal substrate is superior to that of the conventional printed circuit board. Many electronic components that are prone to generate high heat during operation, such as high-power light-emitting diodes, can use a conventional thermally conductive metal substrate as a carrier to improve the problem of overheating. The heat conductive dielectric layer is a key material of the metal substrate. In the prior art, the resin is mixed with a heat conductive powder, so that the resin has a better heat transfer coefficient than the general resin.

Referring to Figure 1, there is shown a schematic view of a conventional thermally conductive metal substrate. The conventional thermally conductive metal substrate 1 includes an underlying metal layer 11, a thermally conductive dielectric layer 12, and a surface metal layer 13. The thermally conductive dielectric layer 12 is disposed between the underlying metal layer 11 and the surface metal layer 13. The conventional method for fabricating the thermally conductive metal substrate 1 is to firstly dispose the resin 121 having a heat conductive effect and the thermally conductive powder 122, and then apply it between the surface metal layer 13 and the underlying metal layer 11. However, there are still many areas for improvement in the fabrication method of the conventional heat conductive metal substrate 1. In order to increase the heat transfer coefficient of the heat conductive dielectric layer 12, a large amount of the heat conductive powder 122 must be added to reduce the coatability of the resin 121. Coverage and adhesion. 2. The particle size of the heat conductive powder 122 is relatively uneven and is not covered by the resin 121, which reduces the continuity between the heat conductive powders 122, so that the heat transfer efficiency of the heat conductive metal substrate 1 as a whole is lowered.

Therefore, it is necessary to provide an innovative and progressive high thermal conductivity metal substrate and a method of manufacturing the same to solve the above problems.

The invention provides a high thermal conductivity metal substrate comprising a first metal layer, a second metal layer and a thermally conductive dielectric layer. The thermally conductive dielectric layer is disposed between the first metal layer and the second metal layer, and the thermally conductive dielectric layer comprises a plurality of spherical thermally conductive powders and a resin.

The invention further provides a method for manufacturing a high thermal conductivity metal substrate, comprising the steps of: (a) disposing a resin on a resin setting surface of a first metal layer; (b) providing a plurality of spherical thermal conductive powders on a second metal a powder setting surface of the layer; and (c) facing the resin setting surface toward the powder setting surface, thermally pressing the resin and the spherical heat conductive powder to the first metal layer and the second metal layer A thermally conductive dielectric layer is formed therebetween.

In the highly thermally conductive metal substrate of the present invention and the method of manufacturing the same, the spherical thermally conductive powders can increase the continuity of the heat transfer path to increase heat transfer efficiency, and thus can be applied to devices having high heat density (for example, electronic components). Can improve the problem of overheating. Moreover, the spherical thermally conductive powders have a relatively average particle size, which makes the thickness of the thermally conductive dielectric layer more uniform. Furthermore, the high thermal conductivity metal substrate does not need to be premixed with the resin and the thermally conductive powder to increase the coating property of the resin.

2 is a flow chart showing a method of manufacturing a highly thermally conductive metal substrate according to a preferred embodiment of the present invention; and FIG. 3 is a schematic view showing a highly thermally conductive metal substrate of the present invention. Referring to FIG. 2 and FIG. 3, first, referring to step S21, a resin 221 is disposed on a resin setting surface 211 of a first metal layer 21. In the present embodiment, the resin 221 is provided on the resin setting surface 211 in a coating manner in step S21.

Referring to step S22, a plurality of spherical thermally conductive powders 222 are disposed on one of the powder placement faces 231 of a second metal layer 23. In this embodiment, the step S22 includes the steps of: electrostatically charging the second metal layer 23; and disposing the spherical thermal conductive powder 222 on the powder setting surface 231. In the present embodiment, the spherical thermally conductive powders 222 are disposed on the powder setting surface 231 by nozzle atomization or sprinkling in step S22.

In other applications, a pre-coat layer (not shown) may be first disposed on the powder setting surface 231, and the spherical heat-conducting powder 222 may be disposed on the pre-coating layer (a nozzle may be atomized or sprinkled) Cloth way).

The second metal layer 23 is electrostatically charged or pre-coated on the powder setting surface 231, which can increase the adhesion between the second metal layer 23 and the thermal conductive powder 222; The heat-dissipating powder 222 is disposed on the powder-disposed surface 231 to increase the uniformity and flatness of the heat-conducting powders 222, and the amount of the heat-conductive powders 222 can be reduced.

Referring to step S23, the resin setting surface 211 is directed toward the powder setting surface 231, and the resin 221 and the spherical thermally conductive powder 222 are hot pressed to form between the first metal layer 21 and the second metal layer 23. A thermally conductive dielectric layer 22.

In this embodiment, the step S23 includes the steps of: rolling the first metal layer 21 (and optionally rolling the second metal layer 23), so that the resin 221 is charged between the spherical thermal conductive powders 222. And a part of the spherical heat conductive powder 222 is in contact with the resin setting surface 211 and the powder setting surface 231; and the resin 221 is heat-cured to form the highly thermally conductive metal substrate 2 of the present invention. Preferably, in step S23, the first metal layer 21 (or the second metal layer 23) is rolled by a rubber roller; and the resin 221 is cured by heat and pressure using a hot press.

Referring to FIG. 3 again, the highly thermally conductive metal substrate 2 of the present invention comprises a first metal layer 21, a thermally conductive dielectric layer 22 and a second metal layer 23. The first metal layer 21 and the second metal layer 23 may be copper or aluminum. Preferably, the resin setting surface 211 and the powder setting surface 231 are surfaces subjected to anodizing, micro-arc oxidation, metal plating or chemical etching surface roughening treatment.

The thermally conductive dielectric layer 22 is disposed between the first metal layer 21 and the second metal layer 23 . The thermally conductive dielectric layer 22 includes the spherical thermally conductive powders 222 having a particle size of 50 to 150 μm, preferably 50 μm. The powder setting surface 231 faces the resin installation surface 211.

The resin 221 of the thermally conductive dielectric layer 22 may be epoxy resin, ruthenium rubber or acrylic resin. The spherical thermally conductive powder 222 of the thermally conductive dielectric layer 22 can be a ceramic powder. The ceramic powder may be alumina, aluminum nitride, cerium oxide or boron nitride. In this embodiment, the spherical thermally conductive powder 222 is located between the first metal layer 21 and the second metal layer 23, and the layer of the thermal conductive powder layer 22 is formed.

Referring to FIG. 4, in other applications, the spherical thermally conductive powder 222 may form two layers of thermal conductive powder layers 223, 224 between the first metal layer 21 and the second metal layer 23, or form more layers. Thermal powder layer. Preferably, the spherical thermally conductive powder 222 of the thermally conductive powder layer 223 is in closer contact with the spherical thermally conductive powder 222 of the thermally conductive powder layer 224. It is clearly shown in FIG. 4 that even if a part of the thermal conductive powder layer (thermally conductive powder layer 223) does not have a thermal conductive powder, the thermal conductive powder layers 223 and 224 of the respective layers also have a continuous heat transfer path, so that Better heat transfer performance.

The invention is illustrated in detail by the following examples in conjunction with FIG. 3, and it is not intended that the invention be limited only by the examples.

Example:

material:

(1) The first metal layer 21 is used as a nickel-plated copper foil (model NIMT-CF-35) of Fukuda Metal Co., Ltd., Japan.

(2) A medium aluminum 5052 aluminum plate was used as the second metal layer 23, and the thickness was 1.5 mm.

(3) The epoxy resin (model KEP-1138) of KOLON Co., Ltd. was mixed with the hardener Nadic Methyl Anhydride at a ratio of 1:1 as the resin 221 in the thermally conductive dielectric layer 22.

(4) A spherical alumina P50 of Denka Corporation was used as the thermally conductive powder 222, and its average particle diameter was 50 μm.

system Ready:

(1) The resin 221 is applied onto the rough surface (resin setting surface 211) of the copper foil (first metal layer 21) by a bar coater of No. 40.

(2) A spherical alumina P50 was sprayed on the aluminum plate (second metal layer 23) with a nitrogen spray gun at a spray amount of 20 mg/cm ² .

(3) The rough surface of the copper foil (the first metal layer 21) coated with the resin 221 is covered on the surface of the aluminum plate (second metal layer 23) with the spherical alumina P50 (thermal conductive powder 222) (powder setting surface) 231) On.

(4) rolling the surface of the copper foil (first metal layer 21) with a rubber roller so that the resin 221 is charged between the spherical alumina P50 (thermal powder 222), and the partially spherical alumina P50 is brought into contact with the Copper foil (first metal layer 21) and aluminum plate (second metal layer 23).

(5) placing the three-layer structure of the rolled copper foil (first metal layer 21), resin 221 + spherical alumina P50 (thermal powder 222), and aluminum plate (second metal layer 23) in a hot press. The resin 221 and the spherical alumina P50 (thermal powder 222) between the copper foil (the first metal layer 21) and the aluminum plate (the second metal layer 23) are thermally pressed at 230 ° C for 2 hours to form the heat conductive dielectric layer 22 . To produce the highly thermally conductive metal substrate 2 of the present invention.

test:

(1) Thermal resistance test: using a guarded heat flow method (according to ASTM E1530) to test the high thermal resistance of the metal substrate 2, the machine type of Unitherm ^TM Model Anter Corporation's 2022, test results show that the high thermal resistance of the metal substrate 2 It is 1.8×10 ^-4 m ² K/W, which is superior to the thermal resistance of a commercially available thermally conductive metal substrate.

(2) Heat resistance test: The heat resistance of the high heat conductive metal substrate 2 was measured by a tin furnace (according to JIS C6481), and the test results showed that the high heat conductive metal substrate 2 can withstand 270 ° C melting for 10 minutes or more.

(3) Subsequent strength test: The peel strength between the copper foil (first metal layer 21) and the aluminum plate (second metal layer 23) was tested by a sintech 50 kN tensile tester (according to JIS C6481), and the test result showed the high thermal conductivity. The metal substrate 2 has an excellent peel strength of 1.2 kN/m.

In the highly thermally conductive metal substrate 2 of the present invention and the method of manufacturing the same, the spherical thermally conductive powders 222 can increase the continuity of the heat transfer path to increase heat transfer efficiency, and thus can be applied to devices having high heat density (for example, electronic components). ), can improve the problem of overheating. Moreover, the spherical thermally conductive powders 222 of the layered cloth have a relatively uniform particle size, which makes the thickness of the thermally conductive dielectric layer 22 more uniform. Furthermore, the high thermal conductivity metal substrate 2 does not need to be premixed with the resin 221 and the thermally conductive powder 222 to increase the coatability of the resin 221.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the scope of the present invention. The scope of the invention should be as set forth in the appended claims.

1. . . Conventional thermal metal substrate

2. . . High thermal conductivity metal substrate of the invention

11. . . Underlying metal layer

12. . . Thermally conductive dielectric layer

13. . . Surface metal layer

twenty one. . . First metal layer

twenty two. . . Thermally conductive dielectric layer

twenty three. . . Second metal layer

121. . . Resin

122. . . Thermal powder

211. . . Resin setting surface

221. . . Resin

222. . . Thermal powder

223, 224. . . Thermal powder layer

231. . . Powder setting surface

Figure 1 shows a schematic view of a conventional thermally conductive metal substrate;

2 is a flow chart showing a method of manufacturing a highly thermally conductive metal substrate according to an embodiment of the present invention;

3 is a schematic view showing a highly thermally conductive metal substrate according to an embodiment of the present invention; and

4 is a schematic view showing another aspect of the highly thermally conductive metal substrate of the present invention.

2. . . High thermal conductivity metal substrate of the invention

twenty one. . . First metal layer

twenty two. . . Thermally conductive dielectric layer

twenty three. . . Second metal layer

211. . . Resin setting surface

221. . . Resin

222. . . Thermal powder

231. . . Powder setting surface

Claims (15)

A method for manufacturing a highly thermally conductive metal substrate, comprising the steps of: (a) disposing a resin on a resin setting surface of a first metal layer; and (b) providing a plurality of spherical thermal conductive powders in a second metal layer The body setting surface includes the steps of: (b1) electrostatically charging the second metal layer; and (b2) providing the spherical heat conductive powder to the powder setting surface; and (c) facing the resin facing surface The body is disposed to heat the resin and the spherical thermally conductive powder to form a thermally conductive dielectric layer between the first metal layer and the second metal layer. The method of claim 1, wherein the resin is disposed on the resin setting surface in a coating manner in the step (a). The method of claim 1, wherein in the step (b2), the spherical thermally conductive powder is disposed on the powder setting surface by nozzle atomization or sprinkling. The method of claim 1, wherein the step (c) comprises the step of: (c1) rolling the first metal layer or the second metal layer to charge the resin between the spherical thermally conductive powders, and A part of the spherical heat conductive powder contacts the resin setting surface and the powder setting surface; and (c2) heat-cures the resin. A highly thermally conductive metal substrate comprising: a first metal layer; a second metal layer having a powder setting surface and being electrostatically charged; and a thermally conductive dielectric layer disposed on the first metal layer and the second metal Between the layers, the thermally conductive dielectric layer comprises a plurality of spherical thermally conductive powders and a tree The grease, the spherical heat conductive powder is disposed on the powder setting surface. A highly thermally conductive metal substrate according to claim 5, wherein the first metal layer is copper or aluminum. A highly thermally conductive metal substrate according to claim 5, wherein the second metal layer is copper or aluminum. The thermally conductive metal substrate of claim 5, wherein the first metal layer further comprises a resin setting surface facing the second metal layer, the resin setting surface being anodized, micro-arc oxidation, plating Metal or chemically etched surface roughened surface. The thermally conductive metal substrate of claim 5, wherein the powder setting surface faces the first metal layer, and the powder setting surface is anodized, micro-arc oxidation, metallized or chemically etched surface roughened surface . The thermally conductive metal substrate of claim 5, wherein the spherical thermally conductive powder is located between the first metal layer and the second metal layer, and at least one thermally conductive powder layer is formed. The thermally conductive metal substrate of claim 5 or 10, wherein the spherical thermally conductive powder has a particle size of 50 to 150 μm. The highly thermally conductive metal substrate of claim 11, wherein the spherical thermally conductive powder has a particle size of 50 μm. A highly thermally conductive metal substrate according to claim 5, wherein the resin is an epoxy resin, a ruthenium rubber or an acrylic resin. The thermally conductive metal substrate of claim 5, wherein the spherical thermally conductive powder system is a ceramic powder. The high thermal conductivity metal substrate of claim 14, wherein the ceramic powder system is oxygen Aluminum, aluminum nitride, tantalum oxide or boron nitride.