JPS63173383A - Steel core enamelle enamelled steel core substrate for printed wiring board and manufacture of the same - 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 Field of the Invention The present invention relates to an iron core enameled substrate for printed wiring boards and a method of manufacturing the same.

(Conventional technology) First, a conventional method for manufacturing an enamel substrate will be explained.

(a) An enameled plate is manufactured by welding enamel to both sides of an iron base material.

(b) A hole is made on one side of the enamel surface by laser processing.

(C) A hole of the same diameter is made in the iron base material at the same position as the hole made in the enamel coating by chemical etching, and a hole is made to communicate between one side of the enamel coating and the iron plate.

(d) Print a pattern on the enamel-coated side without holes.

(e) Insert the electrode to be connected to the pattern printing into the communicating hole created in step (C).

(Problems to be Solved by the Invention) The enamel substrate produced by the above method has the following drawbacks.

In other words, the distance between the holes made in the iron base material is 2.71 cm, which is narrower than the thickness of the iron base material normally used, which is 0.4 mm, so in the case of chemical etching, side etching or over etching is difficult. As a result, the part of the iron base material forming the partition wall of the through hole falls off, and the purpose of the iron base material to reinforce the enamel cannot be achieved.

The inventors of the present invention have carried out various studies aimed at developing a manufacturing method for enamel substrates that does not have this drawback. As a result, we have found that the drilling of holes in the iron base material is a process, the process of crimping copper foil on the iron base material and the process of coating with enamel, and the laser coating on the enamel film. Anaki invented a method for manufacturing enamel substrates, which consists of a process in which the enamel coating on the copper foil and the part blocking the hole in the iron base material are removed by electrolysis. However, this method requires a high temperature of 800° C. or higher and a high pressure of 20 g/m+*2 to press-bond the copper foil, and furthermore, it is not possible to press-bond the copper foil to both sides of the iron substrate.

(Means for Solving the Problems) The present inventors completed the present invention as a result of various studies aimed at solving the above-mentioned problems.

Namely, the present invention provides an iron base material for printed wiring boards, which has an iron base material as a core, a copper film formed to cover the entire surface of the iron base material, and an enameled coating formed to cover the entire surface of the copper film. A copper film is formed on the entire surface of the core enameled substrate and the iron base material by electric polishing, and then enameling is performed on the entire surface of the copper film so that the core is the iron base material, the first layer is the copper film, and the second layer is The present invention relates to a method of manufacturing an iron core enamel substrate for a printed wiring board, which is an enamel coating.

Next, the present invention will be explained based on the drawings.

FIG. 1 is a perspective view of an iron core enamel substrate 1 of the present invention.
The entire surface is covered with an enameled coating.

FIGS. 2 and 3 are lines A-A in FIG. 1, respectively.

It is a sectional view taken along the line BB. In the figure, 2 and 3 degrees 4 indicate the enamel coating, the copper coating, and the iron base core, respectively.

This iron core enamel substrate is manufactured by forming a copper film 2 on the entire surface of an iron base material 1 by electroplating, and then enameling the entire surface of the copper film to form an enamel coating.

Note that the iron base material may be one on which copper is crimped in advance. Alternatively, the copper foil may be crimped after copper plating.

Furthermore, after electroplating the copper plating film, tin-cobalt alloy plating, or tin-cobalt alloy plating, the enamel film forming treatment may be performed.

In this case, the stability of the coating on the substrate is even greater.

(Effects of the Invention) The iron core enamel substrate according to the present invention has improved thermal conductivity and electrical conductivity, and smooth heat dissipation because the entire surface of the iron base material is covered with a copper film and an enamel film. ,
Heat accumulation on the board is eliminated.

Therefore, not only the reliability of the board itself but also the entire device in which this board is incorporated becomes extremely high.

In addition, the formation of the copper film in the method of the present invention is not by crimping different metals onto the iron base material, but by electroplating, which does not require high pressure as in the case of crimping, and can be carried out at room temperature and normal pressure. . Furthermore, a copper film or enamel coating can be formed on the entire surface of the iron base material. Furthermore, if an iron base material to which copper has been crimped in advance is used, a copper film can easily be formed on the parts where copper is not crimped. When the copper crimping method is used in combination, the adhesion is further improved in both cases because the crimped steel and the electroplated coated steel are of the same type of metal.

(Example) Example 1 An iron base material with a thickness of 0.4 mm, a set width of 30 mm, and a length of 2001 cm was subjected to pretreatment such as degreasing in a normal electroplating method to clean and activate the surface of the base material. Then, strike copper plating is performed to a thickness of 0.5 to 1. OIL strike copper was formed. Subsequently, copper sulfate plating was performed to form a copper coating with a thickness of 36 JL over the entire surface of the iron base material. Next, enameling was performed by firing at 500 to 550°C for 10 minutes to produce an iron core enameled substrate of the present invention.

Table 1 shows strike copper plating conditions and copper sulfate plating conditions.
Shown in Table 2.

Table 1 Table 2 Example 2 This product was treated in exactly the same manner as in Example 1, except that copper pyrophosphate plating was performed instead of copper sulfate plating to form a copper film with a thickness of 18 IL on the entire surface of the iron base material. An inventive iron core enameled substrate was manufactured.

Table 3 shows the copper pyrophosphate plating conditions.

Table 3 Examples 3 and 4.5 The same treatment as in Example 1 was performed to first form a copper plating film on the entire surface of the iron base material, and then a tin-nickel alloy film was formed on the entire surface of the iron base material in Example 3. In 4.5, after forming a tin-cobalt alloy film, enameling was performed at a firing temperature of 800°C to produce an iron core enameled substrate of the present invention. Bath compositions and plating conditions for forming each alloy film are shown in Tables 4, 5, and 6.

Table 4 Table 5 Table 6 Example 6 Thickness 0.6 nm, Width 25 [111, Length 1.00 ml]
40g/18pL of copper foil on 11 iron base material at 900°C
It was pressed onto both sides of the substrate with a pressure of mm2, and then copper strike and copper sulfate plating were performed in the same manner as in Example 1 to form a copper film with a thickness of 18 mm. The copper film was formed on both the pressure-adjusting pressure-bonded surface and the copper non-pressure-bonded surface. Then, the firing temperature was 400°C.
The iron core enameled substrate of the present invention was manufactured by performing the enameling treatment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an iron core enamel substrate according to the present invention;
Figure 2 is A-A of Figure 1! ! FIG. 3 is a sectional view taken along line B--B in FIG. 1. In the figure, 1 is an iron core enamel substrate, 2 is an enamel coating, 3 is a copper film, and 4 is an iron base core. Patent Applicant Kosa Co., Ltd. Figure '1 Figure 2

Claims (3)

[Claims] (1) Iron core enamel for printed wiring boards, which has an iron base material as a core, a copper film covering the entire surface of the iron base material, and an enamel coating covering the entire surface of the copper film. substrate. (2) A copper film is formed on the entire surface of the iron base material by electroplating, and then an enameling treatment is performed on the entire surface of the copper film, so that the core is the iron base material, the first layer is the copper film, and the second layer is the copper film. A method of manufacturing an iron core enameled substrate for a printed wiring board in which the layer is an enameled coating. (3) A method for manufacturing an iron core enamel substrate according to claim 2, wherein the iron base material is preliminarily bonded with a copper film.