JPS6033912B2 - Manufacturing method of hollow board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a hollow substrate using an electrodeposition method.

[Technical Background of the Invention] As is well known, a hollow substrate in which the periphery (surface) of a base metal is hollowed is known.

Such a board is widely used as a circuit board on which hybrid ICs and the like are mounted because it has a high mechanical strength because the core is made of metal, and is excellent in terms of heat radiation and cost. There are various methods for enameling, such as electrodeposition, electrostatic coating, spraying, dipping, and brush coating, but among these methods, there are fewer surface defects such as pinholes, and a thicker film. The lightning bonding method is superior in that the voltage is constant and the dielectric strength voltage at the edge of the board can be increased. [
[Problems with the background technology] However, the enamel substrate obtained by the conventional sintering method also has many pinholes and cannot be used for hybrid I.
This is insufficient as a substrate for C mounting. [Object of the Invention] The present invention has been made in view of the above circumstances, and has a hollow with a constant film thickness around the base metal with few surface defects such as pinholes, and has a dielectric strength of not only flat parts but also edge parts. The purpose of the present invention is to provide a method for manufacturing a high-quality hollow substrate.

[Summary of the invention]

The applicant proposed the following as a glass coating technique using an open deposition method (Japanese Patent Publication No. 56-138058).
.

This is related to the glass coating method (passivation film formation) for semiconductor devices, and the following applies to glass powder per night:
A method of immersing a semiconductor element in an organic solvent system in which at least one of metal salts of 20, La", Mg20, and Y30 is dispersed in 1 x 10-5 to 2 x 10-3 mol and depositing it by lightning. It has been confirmed that good exposure can be achieved by using an organic solvent system containing a predetermined amount of metal salts.Therefore, the present inventors investigated the use of metal salts instead of semiconductor elements. As a result of repeated various experiments, P
b20, Zn20, B220, Mn20, Ce40, C
e30, mountain 30, 0a20, evil 20, Mzu10, and Y3
When adding at least one metal salt out of ten metal salts to the glass powder and attaching it to the metal by an exposure method, polyethylene glycol is added to the glass powder mixture at a rate of 5 x 10-4 per 12 glass powders. By adding more than
A hollow substrate with a constant film thickness and a high dielectric strength at the flat portion and at the edge of the substrate was obtained. Here, the behavior of the glass powder during exposure will be explained in detail. Glass powder is generally negatively charged, including Pze+, Zn20, B920, M
n20, Ce40, Ce30, AI30, Y30, Ga
In a solution containing metal salts such as 20, 20, M20, etc., the specified metal salts are adsorbed to each particle of glass powder, positively charging the glass powder, and when a voltage is applied, the glass powder easily causes haze to form on the negative electrode. Furthermore, if 5×10 −4 or more of POIJ ethylene glycol is added to each piece of glass powder in this state, the thickness of the enamel layer formed around the base metal becomes thicker than when it is not added at all. In addition, the amount of polyethylene glycol added is 5 × 10-
If it is less than 4 ta, crystal defects such as pinholes cannot be sufficiently reduced. Furthermore, even if the amount of polyethylene glycol exceeds 5 x 10-2g, the effect will not change, so from the point of view of cost, the upper limit has been changed to 5 x 10-2g.
It is desirable to do so. In the enamel substrate obtained under the above conditions, the number of pinholes after firing is 1/5 to 1/3 compared to when polyethylene glycol is not added.
The thickness of the enamel layer increases by 1.1 to 1.4 times. Also, if this thickness is, for example, 100 m to 130 m
, the dielectric strength increases by about IKV. Furthermore, the thickness of the enamel layer is constant. [Embodiments of the Invention] The present invention will be described with reference to it.

First, after degreasing and cleaning the area around the decarburized steel 1 for enamel,
Electroless nickel plating applied.

400 g of glass powder (glass frit) having the composition shown in the table below was dissolved in 8U of inpropyl alcohol to obtain one glass powder mixture.

Next, IW
An electrolyte solution was prepared by adding a mixed solution of C and 2 g of polyethylene glycol (average molecular weight 300) to the solution 5 dissolved at t% to the glass powder mixed solution. Next, the decarburized steel 1 for enamel was set, and a glass fiber IJ was attached to the surface of the decarburized steel 1 by electrolysis. After this, the decarburized steel 1 was dried at 1500 C for 1 minute, and then heated at 850 oC.
A hollow substrate 3 in which a hollow layer 2 was coated around a decarburized steel 1 was manufactured by firing for 3 minutes. According to the above example, the film thickness of the hollow layer 2 of the substrate 3 can be made to 120 meters by one electrolysis, and this film thickness is greater than that of the substrate obtained without adding polyethylene glycol PEG. This was an increase of approximately 251 m compared to that of .

At this time, the surface of the enamel layer 2 was delicate, and the variation in film thickness was as small as 4 mm, and there were only 2 pinholes that could be observed with the naked eye in a 2 x 3 (inch) substrate. . Further, the dielectric strength voltage of the hollow layer 2 of the substrate 3 is 2. Song VDC or higher, 1 at the end. is above VDC, P
It was confirmed that both the flat portion and the edge portion increased by 20% or more compared to the hollow substrate obtained without adding EG.
Further, in the substrate 3, the adhesion strength of the enamel layer 2 to the decarburized steel 1 was about three times that of the enamel substrate obtained without adding PEG. In the above examples, decarburized steel for enamel was used as the base metal, but other metals or alloys such as copper may also be used, if the composition of the glass frit and manufacturing conditions are appropriately selected. A hollow substrate having similar effects can be obtained.

[Effects of the Invention] As described in detail above, according to the present invention, the hybrid fabric has a hollow layer of a constant thickness with fewer pinholes around the base metal than in the past, and has a high dielectric strength voltage at the edges and flat areas. Hollow material that can be used to mount ICs, etc.
A method for manufacturing a substrate can be provided.

[Brief explanation of the drawing]

The figure is a sectional view of a hollow substrate obtained by the present invention. 1... Ho.

Claims (1)

[Claims] 1 Pb^2^+, Zn^2^+, Ba^2^+, Mn
^2^+, Ce^4^+, Ce^3^+, Al^3^+
, Ga^2^+, La^2^+, Mg^2^+ and Y^
At least one type of metal salt among the 3^+ metal salts is added to the glass powder, and when it is attached to the surrounding metal base by electrodeposition and fired to produce an enamel substrate, it is added to the glass powder mixture. A method for manufacturing an enamel substrate, characterized in that polyethylene glycol is added in an amount of 5×10^-^4g or more per 1g of glass powder.