JPS5877296A - Heat sink board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat dissipation board for a high power circuit in which circuit elements that consume a large amount of power and generate a large amount of heat must be incorporated.

Conventional high-power circuits are made by forming conductors on insulating substrates such as ceramic plates or glass plates using screen printing or vapor deposition methods, and passive circuit elements such as resistors and capacitors, and active circuit elements such as transistors. It was formed by incorporating it.

However, in the above configuration, since the substrate is an insulating material such as ceramic glass, heat dissipation is a problem.When resistors and transistors designed for high power are incorporated, the resistors and transistors generate a lot of heat. Therefore, there is a risk that the heat may destroy not only peripheral components such as capacitors, but also resistors and transistors themselves. Furthermore, even if the damage does not result in destruction, the electrical characteristics often change significantly. In order to counter this and improve reliability, it is often the case that a large aluminum heat sink is separately fabricated and installed between the conductor and the circuit element to prevent the temperature of the circuit element from rising.

Alternatively, in order to effectively dissipate heat, an aluminum metal plate is used, and the entire surface of the aluminum plate is anodized to form an aluminum oxide film, which is used as an insulating substrate. However, in this case, the aluminum oxide film is very sensitive to heat and cracks at 120°C, and cracks occur even at a temperature difference of 110°C. Therefore, electrical insulation becomes a big problem. As a measure against electrical insulation, some aluminum oxide films are coated with a resin, but the resin layer deteriorates heat dissipation.

Insulating substrates with a resin layer directly on the surface of an aluminum plate are also used, but due to the problem of pinholes in the resin layer and its electrical insulation, the resin layer naturally becomes thicker and has very poor heat dissipation. 0 In addition, conventional conductors on insulating films can be formed by applying a conductor material using a screen printing method and curing it, by depositing a film using a mask using a vapor deposition method, or by using an electroless plating method. However, it requires more man-hours and is complicated.

As described above, conventional heat dissipation boards are unsuitable as heat dissipation boards for high-power circuits in which circuit elements that consume large amounts of power and generate large amounts of heat must be incorporated, and have many drawbacks.

The present invention solves the above-mentioned drawbacks by effectively dissipating the heat generated from resistors and transistors, and providing excellent electrical insulation.
The present invention provides a heat dissipation board that has a simple structure and can be mass-produced.The present invention will be described in detail below with reference to the drawings.

The structure of the heat dissipation board of the present invention is as shown in FIGS. 1 and 2. A treatment agent in which silicon oxide is stably dispersed in a varnish made of silicone resin and a solvent is applied and hardened on at least one surface of an aluminum plate 1. This is achieved by forming an insulating film 2 (so-called Vesta treatment using the Vesta treatment agent of the Dow Corning Company method) and depositing a metal-clad dinolint substrate 3 on the film 2.

The heat dissipation board of the present invention constructed in this way has very good heat resistance because it is coated with a PESTA treatment agent in which silicon oxide is stably dispersed in a varnish containing silicone resin and solvent on the aluminum surface. In contrast to conventionally used aluminum oxide films that crack when heated to about 120°C, no cracking occurs even when heated at 350°C for 10 minutes. Thermal shock resistance is also extremely high, and in the case of aluminum oxide film only, a temperature difference of about 110°C will cause the film to crack, but even after heating at 30°C for 10 minutes, immediately immersing it in water at 20°C will not cause film cracking. do not have. Application methods include dip method, spray method,
Any method such as electrostatic painting can be used, and almost no pinholes are observed, showing extremely high corrosion resistance. Further, even when immersed in boiling water for about 500 hours, no blackening occurs, and it exhibits excellent hot water resistance.

When applied by the dip method, the film produced by Vesta treatment is 1
A film thickness of 4 to 6 μm can be obtained in one treatment. Since the film can be made thin in this way, when a resistor or transistor is incorporated, the heat generated from the resistor or transistor can be quickly transmitted to the aluminum plate and dissipated into the outside air.

In addition, a metal-clad printed circuit board 3 is placed directly on the insulating film 2.
Since it is formed by adhesion, a conventional conductive material is applied and cured using a screen printing method. Alternatively, a conductor material is deposited on the entire surface using a vapor deposition method, electrolytically plated, and then etched into a pattern. Alternatively, A? The conductor 5 can be obtained by turn etching.

In addition, due to the structure of the aluminum plate 1, the film 2 formed by PESTA treatment, and the metal-clad printed circuit board 3, the insulation film layer is doubled, so the board has sufficient pressure resistance required for high power applications, and is electrically insulated. It has become a sexual thing. Because the film produced by the Gavesta treatment can be formed extremely thin, even when heat-generating circuit elements such as resistors and transistors are incorporated, heat can be immediately transferred to the aluminum plate and dissipated to the outside air.

As described above, the heat dissipation board of the present invention is obtained by applying PESTA treatment to the entire surface of an aluminum plate to obtain an insulating board, and then forming a metal-clad printed circuit board on the insulating film, and this structure is extremely simple. It can be easily formed with a uniform thickness.

Furthermore, it has excellent electrical insulation properties and has a large heat dissipation effect, so it can be used as a heat dissipation board for high power circuits in which circuit elements that consume large amounts of power and generate large amounts of heat must be incorporated.

Examples of the present invention will be described below.

Example 1 This will be explained with reference to FIG.

The aluminum plate 1 has a thickness of 2.0, a length of 2oα,
□ A piece with a width of 10 crn was used. After degreasing the aluminum plate 1 with acetone, it was immersed in a solution of 10% sodium hydroxide and 1% sodium hydroxide for 3 minutes. This is washed with pure water, immersed in concentrated nitric acid for 1 minute, thoroughly washed with pure water, and dried to obtain an aluminum material. Next, it was coated using Dow Corning's Vesta treatment agent by a dip method and heated at 150°C at 30°C.
Cured in minutes, then coated with Vesta treatment (thickness approx. 5 μm)
) 2 was formed on the film 2 of the aluminum plate 1. Then, the epoxy adhesive 4 was thinly coated on the coating 2 formed by the PESTA process on the aluminum plate 1 (to a thickness of approximately 10 to 20 μm), and the single-sided copper-clad paper phenolic substrate (base material thickness 1.5 μm) was applied. A heat dissipation board of the present invention could be obtained by laminating 0II11 copper foil (35 μm) 3 and curing the epoxy adhesive at 160° C. for 15 minutes.

Example 2 This will be explained with reference to FIG.

An aluminum material was obtained in the same manner as in Example 1.

Next, using Dow Corning's PESTA treatment agent, apply it to the aluminum plate 1 by dipping (approximately 5 cm thick).
μm). A single-sided copper-clad paper phenolic substrate (substrate thickness 0.5 mu, copper foil 35 mu) 3 is then laminated onto the applied PESTA treatment before curing. After that, 15
By curing at 0° C. for 30 minutes, a heat dissipating substrate of the present invention could be obtained. However, in this case, since the Vesta treatment agent was applied using the dip method, the aluminum plate 10
Uncured films are formed on both sides. Therefore, a release film was applied to the opposite side to which the one-sided copper-clad paper phenol substrate was laminated.

A circuit was formed on the heat dissipation boards obtained in Example 1 and Example 2, and peripheral components such as resistors, transistors, and capacitors were attached to the heat dissipation boards, and a high power circuit board was assembled and the heat dissipation characteristics were investigated. . The results are shown in FIG.

A is a paper phenol board, B is a glass epoxy board, C is a ceramic board, D is a conventional aluminum board, and E is a heat dissipation board of Example 1 of the present invention. F is a heat dissipation substrate of Example 2 of the present invention.

As described above, the heat dissipation board of the present invention effectively dissipates the heat generated from resistors and transistors, has good electrical insulation, has a simple structure, is suitable for mass production, and has practical value. be.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of Example 1 of the present invention, FIG. 2 is a cross-sectional view showing the structure of Example 2 of the present invention, and FIG. 3 is a diagram showing the heat dissipation characteristics of various substrates. DESCRIPTION OF SYMBOLS 1... Aluminum plate, 2... Insulating film by Vesta treatment, 3... Metal-clad printed circuit board (single-sided steel-clad 9 paper phenol board), 4... Adhesive, 5... Electric conductor. Figure 1

Claims (1)

[Claims] A treatment agent in which silicon oxide is stably dispersed in a varnish made of silicone resin and a solvent is applied to at least the entire surface of an aluminum plate and cured to form an insulating film, and a metal-clad ziglint substrate is adhered and formed on the film. A heat dissipation board featuring: