JPH0147038B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for attaching heat-generating electronic components (hereinafter referred to as electronic components), and in particular, when attaching electronic components, the adhesive layer surface of a heat dissipating sheet provided with an adhesive layer having excellent thermal stability and electrical insulation properties is applied to the electronic components and The present invention relates to a method of attaching an electronic component by arranging it in contact with the surface of a heat sink. Generally, when using electronic components, heat is generated from the electronic components, so heat dissipation bodies such as heat dissipation fins and metal plates are attached to dissipate the heat. A suitable insulator is required. Various insulators have been proposed for use in attaching such electronic components. For example, (1) mica plate, (2) polyester foil, (3) insulating plate made by bonding a metal substrate and dielectric ceramic thin plate (Utility Model Application Publication No. 54-49864), and (4) heat-resistant rubber filled with metal oxide. heat dissipation sheet (Utility Model Publication No. 52-34947)
can be given. However, since the surfaces of (1) and (2) are relatively rough, air with poor thermal conductivity is present at the contact surface between the insulating material, electronic components, and heat sink, resulting in heat loss and thermal efficiency. is bad, especially
Type (1) lacks uniformity, and type (2) has poor thermal conductivity, and even if it is possible to prevent these defects by applying grease when installing them, it is time-consuming. However, the effect is small and it is not practical. Since the type (3) has a composite structure in which a metal base and a dielectric ceramic thin plate are integrally bonded, the selection of conductive adhesive and adhesive strength are issues. Furthermore, if the surfaces of the heat dissipation sheet, electronic component, and heat dissipation body are not smooth, adhesion will be poor, so the surfaces of the thin ceramic plates are polished to make them thin and smooth while they are adhered. In addition, it is necessary to have a structure that takes into consideration the prevention of tightening strain when screwing, which has the disadvantage of complicating the structure. Regarding item (4), when the heat dissipation sheet is sandwiched between the electronic component and the heat dissipation body and screwed together as shown in Figure 1, the heat dissipation sheet may shift on the heat dissipation body, resulting in poor workability. Worse, there were problems in that dielectric breakdown occurred between the electronic component and the heat sink, the heat sink sheet was destroyed, or the inherent properties of the heat sink sheet were impaired. The present inventor has arrived at the present invention as a result of conducting various studies on methods of preventing displacement during installation without impairing the uniform, excellent thermal conductivity and electrical insulation properties of conventional heat dissipation sheets. The present invention is aimed at solving these drawbacks, and is a silicone rubber sheet filled with an inorganic filler having excellent electrical insulation properties and having adhesive properties on at least one side, which has excellent insulation properties and thermal conductivity. A heat generating system that solves conventional problems such as workability, adhesion, electrical insulation, and thermal conductivity by attaching electronic components to the heat sink without impairing the inherent properties of the heat dissipation sheet. The present invention aims to provide a method for attaching electronic components. That is, the present invention provides a heat dissipating sheet made of silicone rubber filled with an inorganic filler with a thickness having excellent thermal stability and electrical insulation properties when attaching a heat generating electronic component to a heat dissipating body via a heat dissipating sheet. After applying an adhesive layer with a thickness of 0.1 to 30 μm and placing the adhesive layer in contact with the mounting surface of the electronic component and/or heat sink, the heat sink sheet is formed without impairing the original properties of the heat sink sheet. The heat generating electronic component is attached to the heat sink through the heat sink. The present invention will be further explained in detail below. The present invention provides a heat dissipation sheet comprising a silicone rubber sheet filled with an inorganic filler and an adhesive layer provided on at least one side of the sheet. A method in which the electronic components and/or the electronic components are placed in contact with the surface of the heat sink, and the electronic components are attached to the heat sink using screws, etc. The heat dissipation sheet used in the present invention is a heat dissipation sheet made of silicone rubber filled with an inorganic filler that has excellent electrical insulation properties and is made of powders such as aluminum oxide, silicon dioxide, zinc oxide, and boron nitride, and has electrical insulation and thermal conductivity. It is made by laminating adhesive layers. The material constituting the adhesive layer may be any adhesive material that has heat resistance and electrical insulation properties, and specific examples thereof include acrylic and silicone adhesives. These commercially available products include Soken Chemical Co., Ltd.'s product name "SK Dyne G-1" Toshiba Silicone.
Co., Ltd.'s product name is ``Toshiba Silicone YR-3340.'' The thickness of the adhesive layer of the heat dissipation sheet of the present invention is important; if it is too thin, the adhesiveness will not be sufficient, and if it is too thick, the thermal conductivity will deteriorate, so the thickness should be 0.1 to 30 μm. , preferably 5 to 15μ. As a method for laminating the adhesive on the heat dissipation sheet, it can be laminated on the heat dissipation sheet using a normal coater method such as a reverse roll coater, a kiss coater, or a knife coater. As a specific means, for example, a method as shown in FIG. 2 can be cited, but the method is not limited to this. Next, in order to attach the electronic component to the heat radiator, the adhesive layer surface of the heat radiator sheet may be placed in contact with the surface of the electronic component and/or the heat radiator, and the electronic component and the heat radiator may be screwed together. In this case, it is convenient for handling to arrange and attach the heat dissipation sheet so that the adhesive layer is in contact with the surface of the heat dissipation body. As explained above, the present invention is for attaching electronic components, especially heat-generating electronic components, by interposing a heat dissipating sheet between the electronic component and the heat dissipating body. A heat dissipation sheet with a layer of heat dissipation material is used, and it is used for electronic components and/or
Or, since the electronic components placed on the surface of the heat radiator and the heat radiator are screwed together, the workability when installing the electronic components is good, and the heat radiator sheet does not shift and has good adhesion, which improves the characteristics of the electronic components. This has the effect of being able to fully demonstrate the The present invention will be described in more detail below with reference to Examples. Example 1 The silicone rubber sheet was Denka Heat Dissipation Sheet, a product of Denki Kagaku Kogyo Co., Ltd. filled with boron nitride, and as shown in Figure 2, a polyethylene film 8 coated with an adhesive 7 with a thickness of 10μ was used. The heat dissipation sheet 4 was dropped from the hopper 9 onto the heat dissipation sheet 4, and the adhesive 7 applied to the polyethylene film 8 was laminated on one side of the heat dissipation sheet 4. The adhesive is a two-component acrylic adhesive manufactured by Soken Kagaku Co., Ltd. under the trade name "SK Dyne G-1" with 0.3% isocyanate curing agent.
was used. Next, the adhesive layer surface of this sheet was placed in contact with the heat dissipation fin surface, and then the transistor was placed and screwed. The displacement of the sheet during this tightening was investigated. The shapes of the heat dissipation sheets are TO-3 type and TO-220 type, the hole diameter of the heat dissipation fin is 5 mmφ, the screws are M3, and the tightening torque is 6 kgfcm. was visually inspected and the percentage of deviation is shown in the table.

[Table] Furthermore, when the thermal resistance and dielectric strength were investigated, the one manufactured by the present invention was 0.27℃/w, and the comparative example was 0.27℃/w.
It was 0.26℃/w. The dielectric strength was 5 KV DC or more in both the Examples and Comparative Examples, and no substantial difference in characteristics was observed. Example 2 The same procedure as in Example 1 was carried out except that the thickness of the adhesive layer was 15 μm. The results were the same as in Example 1. Example 3 The same procedure as in Example 1 was carried out, except that the silicone adhesive was Toshiba Silicone Co., Ltd. under the trade name "Toshiba Silicone YR-3340" and the adhesive layer had a thickness of 5 microns. The results were the same as in Example 1. Example 4 The same procedure as in Example 1 was carried out except that the silicone adhesive layer of Example 3 was provided on both sides of the sheet to a thickness of 5 μm. The deviation during screw tightening was the same as in Example 1.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram of a transistor mounted on a heat radiation fin, and FIG. 2 is a schematic diagram of manufacturing a single-sided adhesive sheet using a reverse roll coater. Numbers 1... Heat dissipation fin, 2... Transistor, 3... Bolt, 4... Heat dissipation sheet, 5... Insulating bush, 6... Nut, 7... Silicone oil, 8... Carrier film, 9 ...Heat dissipation sheet supply hopper.

Claims (1)

[Claims] 1. When attaching a heat-generating electronic component to a heat sink via a heat-dissipating sheet, at least one side of the heat-dissipating sheet made of silicone rubber filled with an inorganic filler has a thickness of 0.1 mm with excellent thermal stability and electrical insulation properties.
After applying an adhesive layer of ~30 μm and placing the adhesive layer in contact with the mounting surface of the electronic component and/or heat sink, the adhesive layer is placed in contact with the mounting surface of the electronic component and/or the heat sink, and then the heat sink is inserted through the heat sink without impairing the original properties of the heat sink. A method for attaching a heat generating electronic component, comprising attaching the heat generating electronic component to a heat sink.