JPS60217696A - Ceramic substrate - 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 Application of the Invention] The present invention improves the adhesion of an organic film such as an overcoat or photoresist formed on a thick copper film in which nickel and gold or only nickel is diffused. This article relates to a featured copper thick film ceramic substrate.

[Background of the invention]

Conventionally, in order to form a copper thick film conductor on a high temperature sintered conductor such as tungsten, nickel and gold or only nickel were applied to the high temperature sintered conductor such as tungsten using a plating method to maintain the bonding reliability with the copper thick film. are doing. This causes nickel or gold or both metals to diffuse into the thick copper film.

The upper part of the diffusion part has the drawback that, for example, an organic film such as a photoresist or solder does not adhere well, and the structure and function of the substrate are restricted, making it difficult to design freely.

[Purpose of the invention]

The purpose of the present invention is to provide a thick copper film characterized by depositing copper by plating on a thick film copper in which a plating metal such as nickel is diffused, thereby improving the wettability of solder and the adhesion strength of photoresist, etc. The purpose is to provide the substrate.

[Summary of the invention]

When using a wet multilayer board in combination with a thick copper film, a method is used in which a high-temperature sintered conductor such as tungsten, molybdenum, manganese, etc. and the thick copper film are plated with nickel or nickel-gold for connection. There is. Since this thick film copper paste is fired in a normal atmosphere at 900 to 1.100 DEG C., the underlying plating metal such as nickel diffuses into the thick film copper.

A thick copper film in which a plating metal such as nickel is diffused has poor solder wettability, and even if an organic film such as an overcoat or photoresist is applied and dried, adhesion is poor. For this reason, in the case of a photoresist, a portion of the thick copper film may be damaged by etching, resulting in deterioration in quality. Therefore, in the present invention, electrolytic copper plating or chemical copper plating is applied to the above-mentioned thick copper film in which nickel or the like is diffused to improve its properties. The thickness of copper plating can be changed freely depending on the purpose.

For example, in the case of organic films such as photoresists, 0
It may be about 2μ. Or for soldering, 0.5μ
It is more effective to plate the above.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of the wet multilayer substrate after sintering.

That is, a tungsten conductor 2 placed on a sintered body 1 of a green sheet is plated with electroless nickel plating of 3μ and gold plating of 0.1μ, and then sintered at 900'C4C, followed by a plating layer 4. did.

An alumina insulating layer 3 is formed on the tungsten conductor 2 other than the plating layer 4. Figure 2 shows the copper paste pattern 5.
When this is printed and dried at 900° C. for 10 minutes in a N atmosphere, a copper pattern 6 is formed in which the plating layer 4 is diffused into the thick copper film. Copper plating 7 was applied thereon to complete the board. Therefore, when we experimented with soldering with and without the copper plating film 7, we found that the solder was completely wetted in 173 hours on the solder with and without the copper plating film 7, and we were able to confirm the results. Ta.

〔Effect of the invention〕

According to the present invention, by applying copper plating on a pattern made of copper thick film paste, the solder wettability of the pattern is improved and the adhesion of organic films such as overcoats and photoresists can also be improved, thereby improving reliability. do.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view after forming a plating film on the tungsten conductor of a wet substrate. Figure 2 is a cross-sectional view after printing and drying the copper thick film paste on the substrate shown in Figure 1. Figure 3 is FIG. 2 is a cross-sectional view of a completed substrate obtained by firing the substrate shown in FIG. 2 and further performing copper plating on the thick film copper. 2...Tungsten conductor. 3...Alumina insulation layer. 4...Ni, Au mesh layer. 5... Thick film copper paste printing layer. 7... Copper plating layer. Figure 1 Figure 2 Figure 3 Port

Claims (1)

[Claims] 1. For ceramic substrates with conductors such as tungsten or molybdenum manganese, nickel plating and gold plating, or only nickel plating, is applied to the conductors, and a thick film is applied to the entire board or part of the plated conductors. The adhesion and solder wettability of organic coatings such as overcoats and photoresists are improved by applying copper paste by printing, etc., and then applying copper plating to the substrate that is fired in a nitrogen atmosphere. Ceramic substrate featuring