TWI302372B - Heat dissipation substrate for electronic device - Google Patents

Description

1302372 IX. Description of the Invention: [Technical Field] The present invention relates to a heat dissipating substrate, particularly to a heat dissipating substrate for dissipating heat of electronic components. [Prior Art] In recent years, white light-emitting diodes (LEDs) have been the most optimistic and most popular products in the world. It has the advantages of small size, low power consumption, long life and good response speed, which can solve the problems that past incandescent bulbs can't overcome. LEDs are increasingly used in display backlights, mini projectors, lighting and automotive lighting sources. At present, countries such as Europe, America and Japan are actively developing white light-emitting diodes as a new light source for this century based on the consensus on energy conservation and environmental protection. Coupled with the fact that many countries now rely on imports for energy, the development is extremely valuable. According to experts' assessment, if Japan replaces the lamp with white light-emitting diodes, it can save the electricity consumption of the two power plants every year. The indirect reduction of fuel consumption is up to the liter, and the two emissions during the power generation process. Oxidation is also reduced, which in turn inhibits the greenhouse effect. Based on this, advanced countries such as Europe, America and Japan are currently betting a lot of manpower to promote research. Ten can replace the traditional luminaires in the next ten years. However, for high-power LEDs for lighting, the input power is only about! 5~2G% is converted into light, and the rest (9)~(iv) is converted into heat. These heats are not able to escape to the environment at the right time, which will cause the interface temperature of the coffee element to be excessive and affect its luminous intensity and life. Therefore, the heat pipe 1302372 of the LED element has become more and more important. Do not 疋 display monthly light source or general illumination, usually a plurality of led components are assembled on a circuit substrate. In addition to the role of the LED module, the circuit board also needs to provide heat dissipation. The working current of the conventional led is only about 20 mA. Since the heat generation is not large, the heat dissipation problem is not serious, so it is only necessary to use a copper foil printed circuit board (PCB) for general electronics. However, with the widespread application of high-power LEDs, the operating current can reach above. It is known that the printed circuit board with copper foil on the surface of glass fiber FR4 (heat dissipation coefficient about W3W/m·K) is insufficient to meet the heat dissipation requirements. . SUMMARY OF THE INVENTION The main object of the present invention is to provide a heat dissipating substrate which has excellent heat dissipation characteristics, and has (four) high voltage dielectric insulating properties, flexible mechanical structural characteristics, and a layer between the metal layer and the thermally conductive polymer dielectric insulating material. The excellent joint tensile strength provides an application such as a high power component such as an LED (for example, a foldable mobile phone). In order to achieve the above object, the present invention discloses a heat dissipation substrate for an electronic component, comprising a first metal layer, a second metal layer, and a thermally conductive polymer dielectric insulating material layer. The surface of the first metal layer carries the electronic component (e.g., a light emitting diode (LED) component). The thermally conductive polymer dielectric insulating material layer is stacked between the first metal layer and the second metal layer to form a physical contact, and the interface between the thermally conductive polymer dielectric insulating material layer and the first and second metal layers Contains at least one slightly rough surface (roughness greater than 7 〇, according to B 0601 1994). The micro-rough surface comprises a plurality of knob-like protrusions, and the particle size of the tumor-like dog product is mainly distributed between 〇1 and 1〇〇μm, and the thermal conductivity of the layer of the thermal conductive high-eight 1302372 sub-dielectric insulating material is greater than 1 W/m · Κ, thickness less than 0.5 mm, and containing: (1) fluoropolymer with a melting point above 150 ° C and a volume percentage between 30-60%; and (2) A thermally conductive filler is dispersed in the fluoropolymer and has a volume percentage of between 40 and 70%. Preferably, the fluoropolymer may be selected from the group consisting of polyvinyl fluorene (PVDF) or ethylenetetrafluoroethylene (PETFE), and the melting point is greater than 150 ° C. Preferably, it is more preferably greater than 220 ° C. The thermally conductive filler can be selected from ceramic thermal materials such as nitrides and oxides. The heat dissipating substrate of the present invention may also be subjected to radiation irradiation of 〇20 Mrad to cure the layer of the thermally conductive polymer dielectric insulating material, in addition to having good heat conduction and insulation effects, if the first metal layer and the second metal are The thickness of the layer is less than 〇·1 mm and 0.2 mm, respectively, and the thickness of the thermally conductive polymer dielectric insulating material layer is less than 〇5 mm (more preferably 0.3 mm), which can be bent into a diameter of 5 mm by rotating the test substrate of 1 cm width. The flexural test of the cylinder does not occur on the surface without cracks or cracks, but it can be used for folding products. In addition, fluoropolymer materials generally have a higher melting point (for example, PVDF of about 165 ° C, PETFE of about 240 ° C) and have flame retardant properties, can withstand high temperatures, and are not easy to ignite, and more safe applications value. Embodiments Referring to FIG. 1, an LED element 10 is mounted on a heat dissipation substrate 20. The heat dissipation substrate 20 includes a first metal layer 21, a second metal layer 22, and a thermally conductive polymer dielectric insulating material layer 23 stacked between the first metal layer 21 and the second metal layer 22. The LED element 10 is disposed on the surface of the first metal layer 21, the surface of the first metal layer 21, and the interface between the first and second metal layers 21 and 22 and the layer of the thermally conductive polymer dielectric material 23 is in physical contact, and wherein At least one interface is a micro-rough surface comprising a plurality of knob-like protrusions, and the particle diameter of the tumor-like protrusions is mainly distributed between 0.1 and 1 μm, thereby increasing the tensile strength between each other. The manufacturing method of the heat dissipation substrate 20 is as follows: the feed temperature of the batch type chain mixer (HAAKE-600P) is set at the melting point of the material (Tm) + 2 〇〇 c, and the formula of the thermal conductive polymer dielectric insulating material layer 23 is added. Premix (the raw material is placed in a steel cup and stirred evenly with a measuring spoon). Initially, the speed of the chain machine rotation was 40 rpm, and after 3 minutes, the rotation speed was increased to 70 rpm, and the chain was further mixed for 15 minutes, and then the material was discharged to form a heat dissipation composite material having heat dissipation characteristics. The above heat-dissipating composite material is placed in a lower symmetrical manner in a mold having an outer layer of a steel plate and a thickness of the desired thickness (for example, 0 · 15 mm), and a layer of Teflon release cloth is placed on the upper and lower sides, and the preheating is performed for 5 minutes. It was further pressed for 15 minutes (operating pressure 150 kg/cm2 'temperature and mixed chain temperature), and then a heat-dissipating sheet having a thickness of 0.15 mm was formed. The first metal layer 21 and the second metal layer 22 are pressed up and down once on the heat dissipating sheet, and preheated for 5 minutes and then pressed for 5 minutes (operating pressure 150kg/cm2, temperature and mixed chain temperature). The heat dissipation polymer dielectric material layer 23 is formed in the middle, and the heat dissipation substrate 20 of the first metal layer 21 and the second metal layer 22 is bonded to the upper and lower sides. Table 1 shows the tensile and to withstand voltage test results of different roughness. The thermal conductive polymer dielectric insulating layer 23 is made of polyvinylfluoride (PVDF) (melting point about i65 ° C). The substrate, • 1302372, is dispersed in PVDF with a thermally conductive filler alumina (Al2〇3), and the volume percentages of the two are 40% and 60%, respectively. In this embodiment, the thickness of the thermally conductive polymer material layer 23 is less than 〇 3 mm. The tensile test was in accordance with Japanese JIS C6481 specification to test the peel strength between the interfaces. Table I

No.__Metal foil thermal conductive polymer layer thickness (mm) Tensile force (N/cm) Thermal conductivity (W/m · K) Withstand voltage test type Specification roughness (Rz) 1 Copper foil 1 oz 7.0-9.0 0.21 14.3 1.7 &gt ;5kV 2 copper foil 2oz 9.5-11.5 0.24 16.8 1.6 >5kV 3 copper foil 4oz 10.0-12.0 0.22 17.5 1.7 >5kV 4 steel-nickel foil 1 oz 9.5-11.5 0.23 16.9 1.7 >5kV 5 copper-nickel foil 2oz 10.0-12.0 0.23 17.8 1.6 >5kV 6 Nickel foil 1 oz 10.0-12.0 0.24 18.1 1.6 > 5kV Controlled copper foil 1 oz 3.0-4.5 0.23 7.5 1.6 > 5kV From Table 1, the surface roughness of the control group ( Rz) lies between 3〇~45 'it is less than the experimental group of 1-6' and its tensile force is 7.5 N/cm far less than the tensile force of the experimental group of numbers 1-6 (at least greater than 8.〇N/cm). It is apparent that a large surface roughness increases the peel strength between the thermally conductive polymer dielectric insulating material layer 23 and the first and first metal layers 21 and 22. In addition, all experimental groups can pass the withstand voltage test of 5kV (or at least greater than 3 kV), and their thermal conductivity is 1302372 greater than 1.0W/m · K. Table 2 is a test comparison table for different types of high molecular polymers. Table II ______

No. Polymer polymer heat conductive South molecular material layer thickness (mm) Thermal conductivity (W/m·K) Tensile force (N/cm) Flexibility (5mm) Tin furnace test (260〇C) Withstand voltage test 1 PVDF 0.22 1.6 14.5 PASS PASS >5kV 2 PETFE 0.24 1.7 16.8 PASS PASS >7kV Control group 1 HDPE 0.21 1.7 15.7 PASS FAIL < 2kV Control group 2 EPOXY 0.20 1.6 22.1 FAIL PASS > 3kV The experimental groups of numbers 1 and 2 were selected respectively PVDF and PETFE (TefzelTM) are used as polymer substrates, while thermal conductive fillers are made of alumina (ai2o3). Polymers of control groups 1 and 2 are selected from non-fluorinated high molecular polyethylene (HDPE) and epoxy resin (EPOXY). ). The volume percentages of the polymer and the thermally conductive filler of the above experimental group and the control group were 40% and 60%, and a copper foil having a roughness Rz of 7.0 to 9.0 was used as the first and second metal layers. The epoxy resin (EPOXY) control group contained liquid epoxy resin, Novolac resin, dicyandiamide, urea catalyst, and alumina (Al2〇3). The liquid epoxy resin is model DER33 1 from Dow Chemical Company; the Novolac resin is from the Dow Chemical Company model DEN 438; the dicyandiamide 13023 is from Dyhard from Degussa Fine Chemicals. 100S; the urea catalyst is Dyhard UR500 from Degussa Fine Chemicals; the alumina has a particle size of 5 to 45 microns and is produced by Denki Kagaku Kogyo Kabushiki Kaisya. The epoxy resin (EPOXY) can be used. The following procedure was prepared by mixing 50 parts of DER331 and 50 parts of DEN 438 in a 80 〇C resin kettle until a homogeneous solution was formed. Next, 10 parts of Dyhard 100S and 3 parts of Dyhard UR300 were added and the mixture was continuously mixed at 80 ° C for 20 minutes in the resin kettle. Thereafter, 570 parts of AI2O3 filler was added to the vinegar jug and mixing was continued until the filler was completely dispersed in the resin to form a slurry. The gas contained in the resin emulsion was removed by vacuum for 30 minutes, then the resin emulsion was placed on the surface of a copper foil, and another copper foil was placed on the surface of the resin slurry to form a copper foil/salt pulp/copper foil composite structure. . The copper foil/salt pulp/copper foil composite structure was placed in a 3 mm thick metal frame, and the surface of the copper foil was flattened using a rubber roller. The composite structure (along with the metal frame) was placed in a 130 ° C oven for pre-cure for 1 hour. Thereafter, the composite structure was placed in a vacuum hot press (vacuum degree: 10 torr, pressure: 50 kg/cm2) together with a metal frame, and further cured at a temperature of 150 ° C for 1 hour. The composite structure was cooled to less than 50 ° C under a pressure of 50 kg/cm 2 and the composite structure was removed from the hot press. The test substrates of the PVDF and PETFE experimental groups and the HDPE and EPOXY control groups were subjected to the following tests: 1) Flexibility: The test substrate of 1 cm width was bent into a cylinder of 5 mm diameter, and the surface was not broken or cracked. situation. 1302372 2. Tin furnace test: Place the test substrate at 260. For 5 minutes, the surface of the tin can not be blistering or other abnormal appearance. 3. Pull force (peel strength) test: According to Japanese Industrial Standard JIS C6481. 4. Dielectric strength (insulation breakdown voltage) test: The withstand voltage test is carried out in accordance with JIS C2110, the industry standard. It can be seen from Table 2 that the experimental group of the fluorine-containing polymer PVDF and PETFE has good flexibility and high temperature resistance, and can withstand a high voltage of 5 kV or more by withstand voltage test. In contrast, the control group 1 using HDPE as a polymer, although passing the flexibility test, did not pass the 260 °C tin furnace high temperature test, and the withstand voltage was less than 2 kV, which was significantly smaller than the experimental groups of Nos. 1 and 2. As for the control group 2 using EPOXY as a polymer, although it can be tested by a high temperature tin furnace, its hardness is high and it is not flexible. In addition, the above-mentioned PVDF and PETFE fluorine-containing materials have the characteristics of being non-flammable and non-combustible (in accordance with UL 94 V-0), and are more safe than HDPE and EPOXY. The volume percentage of the fluoropolymer and the thermally conductive filler can be adjusted to some extent while still maintaining the same characteristics. Preferably, the volume percentage of the fluoropolymer is between 30 and 60%; and the volume percentage of the thermally conductive filler is between 40 and 70%, and more preferably between 50 and 65%. In addition to the above materials, the thermally conductive polymer may also be selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoro-propylene copolymer (FEP), and ethylene. Tetrafluoroethylene copolymer-12- 1302372

(ethylene-tetrafluoroethylene copolymer; ETFE), perfluoroalkoxy modified tetrafluoroethylenes (PFA), poly(chlorotri-fluorotetrafluoroethylene; PCTFE), second gas Vinidyl fluoride-tetrafluoroethylene copolymer; VF-2-TFE), poly(vinylidene fluoride), tetrafluoroethylene-perfluorodioxetane copolymer (tetrafluoroethylene-perfluorodioxole copolymers), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluor opr opylene Tetrafluoroethylene terpolymer), and tetrafluoroethylene-perfluoromethylvinylether, a tetraester-terminated urethane (cure site monomer terpolymer). The heat conductive filler may be selected from a nitride or an oxide. The nitride includes zirconium nitride (ZrN), boron nitride (BN), aluminum nitride (AIN), and silicon nitride (SiN). The oxide includes aluminum oxide (AI2O3), magnesium oxide (Magnesium oxide; MgO), zinc oxide (ZnO), titanium dioxide (Titanium dioxide; Ti02). In addition, if the high-voltage light-emitting element is applied to the LED, the first metal layer 21 carrying the LED element 10 can be made of copper, and the related circuit of the LED element can be fabricated, and the second metal layer 22 at the bottom can be made of copper. Aluminum or its alloy. -13- 1302372 The heat dissipating substrate of the invention not only has high thermal conductivity, high voltage resistance, high temperature resistance and the like, but also has high tensile strength and flexibility, and can be applied to heat dissipation of LED modules for current lighting, and even It can be used for folding heat sink applications such as notebook computers and mobile phones. The technical contents and technical features of the present invention have been disclosed as above, and those skilled in the art can still make various substitutions and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should be construed as being limited by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates a heat dissipation substrate according to an embodiment of the present invention. [Main component symbol description] 10 LED component 2 0 heat dissipation substrate 21 first metal layer 22 second metal layer 23 thermal conductive polymer dielectric insulating material layer -14-

Claims (1)

1302372 X. Patent application scope: 1' - a heat dissipating substrate for an electronic component, comprising: a first metal layer, one surface of which carries the electronic component; a second metal layer; and a thermally conductive polymer dielectric insulating material layer, Laminating between the first metal layer and the first metal layer and forming a physical contact, the interface between the thermally conductive polymer dielectric insulating material layer and the first and second metal layers includes at least one roughness • the degree Rz is greater than 7· a micro-rough surface comprising a plurality of knob-like protrusions, wherein the diameter of the knob-like protrusions is mainly distributed between 0.1 and 100 micrometers, and the thermal conductivity of the layer of the thermally conductive polymer dielectric insulating material is greater than K 'thickness is less than 〇^πιηι, and contains: (1) a fluorine-containing southern molecular polymer having a melting point higher than 15 ° C and a volume percentage between 30-60%; and (2) a thermally conductive filler, dispersed In the fluorine-containing polymer, and the volume percentage thereof is between 4 〇 7 〇 ° / 。. • The heat sink substrate of the electronic component of claim 1, wherein the first metal layer has a fullness of less than 0.1 mm. 3. The heat dissipating substrate of the electronic component according to claim 1, wherein the second metal layer has a fullness of less than 0.2 mm. The heat-dissipating substrate of the electronic component according to π, wherein the fluoropolymer has a melting point higher than 220 °C. The heat dissipating substrate of the electronic component of claim 1, wherein the thermally conductive filler has a volume percentage of 50-65%. According to the heat-dissipating substrate of the electronic component of claim 1, wherein the heat-conductive polymer *1302372 dielectric insulating material layer first and second electrode (four) has a tensile strength greater than 8 N/cm. 7. The heat-dissipating substrate of the electronic component according to claim 1, wherein the test substrate is 1 cm wide and the surface of the test substrate is not broken or cracked when it is bent into a cylinder having a diameter of 5 mm. 8. The heat-dissipating substrate of the electronic component according to claim 1, which is placed in the tin furnace for 5 minutes, and has no blistering on the surface and an abnormal appearance. The heat-dissipating substrate of the electronic component according to claim 1 which is resistant to a voltage greater than 3 kV. The heat-dissipating substrate of the electronic component according to claim 1, wherein the gas-containing polymer poly-a system is selected from the group consisting of polyfluorinated Ethylene or ethylene-tetrafluoroethylene copolymer. The heat dissipation substrate of the electronic component according to claim 1, wherein the gas-containing polymer agglomerate is selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene hexapropylene copolymer, and ethylene-tetrafluoroethylene copolymer. Perfluorocarbon oxygen modified tetrafluoroethylene, poly(gas trifluorotetrafluoroethylene), difluoroethylene-tetrafluoroethylene polymer, polydifluoroethylene, tetrafluoroethylene-perfluorodioxole copolymer Monomers of monomers, difluoroethylene-/fluoropropane copolymer, difluoroethylene-hexafluoropropylene-tetrafluoroethylene terpolymer and tetrafluoroethylene-perfluorodecyl vinyl ether plus solidification domain Things. 12. A heat dissipating substrate for an electronic component according to the claims, wherein the thermally conductive filler is selected from the group consisting of nitrides or oxides. 13. The heat dissipating substrate of the electronic article according to claim 12, wherein the nitride is selected from the group consisting of a nitriding hammer, boron nitride, aluminum nitride, and tantalum nitride. The heat-dissipating substrate of the electronic component according to claim 12, wherein the oxide is selected from the group consisting of alumina, magnesia, zinc oxide, and titanium oxide. -1302372 15. The heat-dissipating substrate of the electronic component according to claim 1 which is subjected to radiation irradiation of $2〇Mraci to cross-link the thermally conductive polymer dielectric insulating layer. 16. The heat-dissipating substrate of the electronic component according to claim 1 The electronic component is a light emitting diode (LED) component. The first metal layer 17. The heat-dissipating substrate of the electronic component according to claim 1, wherein the heat-containing substrate comprises steel. 18. = The heat sink substrate of the electronic component of claim 1, wherein the second metal layer contains the name.