JPH02269788A - Adhesive composition for additive-process printed wiring board - Google Patents

Abstract

PURPOSE:To obtain the title composition which serves to control the occurrence of copper migration and makes it possible to form a wiring board with fine lines by incorporating a mercaptotriazine compound and a specified compound into a mixture of a rubber with a thermosetting resin. CONSTITUTION:100 pts.wt. mixture of a rubber with a thermosetting resin (e.g. a mixture of a styrene/butadiene copolymer rubber with a novolak epoxy resin) is mixed with 0.1-10 pts.wt. mercaptotriazine compound (e.g. 2,4,6- trimercapto-s-triazine) and 0.1-10 pts.wt. compound selected from among a benzimidazole, benzotriazol and o-phenanthroline compounds. The incorporation of said compounds into said mixture makes it possible to control copper migration, prevent the decrease in the insulation resistance of a wiring board product, and realize the formation of a densely wired board without adversely affecting the basic physical properties of an adhesive composition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to adhesive compositions used to coat insulating substrates of additive printed wiring boards.

[Conventional technology]

Some printed wiring boards are manufactured by an additive method, which is one of the manufacturing methods.

Here, the additive method refers to laminating an additive layer on a substrate, and making the surface of this additive layer hydrophilic in an oxidizing agent solution such as a chromic acid mixture (Crys + HzS(la) or a permanganate solution). After (roughening) this surface, an electroless plating catalyst such as palladium is applied to the surface to perform a surface activation treatment (however, an electroless plating catalyst is added to the adhesive composition for insulating substrates and additive printed wiring boards in advance). (If the catalyst is applied, the catalyst application step is omitted), then apply a photosensitive lacquer to the non-circuit forming portion of this surface using a photographic method, or form a circuit using a resist agent such as resist ink or dry film resist using a screen printing method. In this method, a plating circuit is formed in the circuit forming part by masking other parts (formation of a resist film) and then electroless plating.

The substrate used to manufacture printed wiring boards by this additive method (hereinafter referred to as additive printed wiring boards) is an insulating substrate made of phenol resin, epoxy resin, imide resin, ceramic, etc., and is coated with an adhesive composition for additive printed wiring boards. The material is coated by a curtain coating method, dip method, etc., and semi-cured or hardened. Further, adhesive compositions for additive printed wiring boards generally consist of rubber/phenolic resin, rubber/epoxy resin, rubber/phenolic resin/epoxy resin, and the like.

The feature of such an additive printed wiring board is that since the circuit faithfully reproduces the pattern formed by the resist, there is no undercut in the circuit compared to the conventional subtractive method, and it is suitable for thinning the circuit. However, the adhesive compositions currently in use for additive printed wiring boards are mainly composed of rubber components such as nitrile rubber, so they are manufactured using a subtractive method using copper-clad glass/epoxy laminates, etc. Generally, the electrical characteristics are inferior to that of printed wiring boards. Therefore, in a high-density wiring board, when the circuits are thinned, a copper migration phenomenon in which copper in the circuits is ionized and moves between adjacent circuits with a potential difference during use under high humidity conditions tends to occur. As this copper migration progresses, the insulation resistance between circuits decreases, eventually leading to short circuits and failures such as malfunction of electrical products, which is a major problem in the current situation where there is a strong demand for thinner wires in wiring boards. It is.

[Problem to be solved by the invention]

An object of the present invention is to provide an adhesive composition for additive printed wiring boards that suppresses the occurrence of the copper migration rays and enables thinning of wiring boards.

[Means to solve the problem]

The object of the present invention is to combine 0.1 to 10 parts by weight of a mercaptotriazine compound and 0.1 to 10 parts by weight of a benzimidazole compound or benzotriazole compound to 100 parts by weight of a mixture of rubber and thermosetting resin. , 0-
This can be achieved by using an additive printed wiring board adhesive composition containing at least one compound selected from the group consisting of phenanthroline compounds.

The adhesive composition for additive printed wiring boards of the present invention contains, in addition to the mercaptotriazine compound, at least one compound selected from the group consisting of benzimidazole compounds, benzotriazole compounds, and 0-phenanthroline compounds. Other than this, it is a composition containing rubber and a thermosetting resin, typified by phenolic resin/epoxy resin, as the compounding components, similar to ordinary adhesive compositions for additive printed wiring boards.

Examples of rubber components include natural rubber, styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), carboxyl-modified NBR, 7'tadiene rubber, chloroprene rubber, isoprene rubber, butyl rubber. etc. The acrylonitrile content of NBR is not particularly limited, and can be selected and used from a wide range of NBRs, from low nitrile NBRs with an acrylonitrile content of less than 25χ to extremely high nitrile NBRs with an acrylonitrile content of 43% or more.

As the phenolic resin of the thermosetting resin component, both novolac type and resol type are used. Epoxy resins include bisphenol/epichlorohydrin type,
There are novolac types and alicyclic types. Further, as these resin components, flame retardant resins such as brominated epoxy resins can be used to impart flame retardancy to the composition. Furthermore, these adhesive compositions for additive printed wiring boards can be used as long as they contain a roughening component and a non-roughening component for imparting appropriate roughness to the surface in the roughening process of electroless plating, such as rubber. /Not limited to the combination of phenolic resin/epoxy resin, etc.
Further, if necessary, a rubber crosslinking agent, a resin curing agent, a filler, a surfactant, a coupling agent, a solvent, an electroless plating catalyst, etc. can be added.

Examples of the mercaptotriazine compound that is incorporated as an essential component in the adhesive composition for additive printed wiring boards of the present invention include 2.4.6-drimerkabuto S-driazine, 2-dibutylamino-4, 6-
dimercapto-S-) riazine, 2-anilino-4,6
-dimercapto-S-+-riazine, 2,4-dimercapto-6-vinyl-S-) riazine, 2-allyl-4,
Examples include 6-dimercapto-S-triazine and 6-diallylamino-1,3,5-triazine-2,4-dithiol.

In addition, benzimidazole compounds include benzimidazole, 2-mercaptobenzimidazole, etc., and benzotriazole compounds include benzotriazole, 2-hydroxy-benzotriazole, 2-(5
-Methyl-2-hydroxyphenyl)-benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-
dimethylbenzyl) phenylgol 2H-benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-t-butyl-5-methy/J/-2-hydroxy phenyl)-5-
Chlorobenzotriazole, 2-(3,5-dibutyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-dibutyl-2-hydroxyphenyl)penzotriazole, 0 −
The phenanthroline compound includes 0-phenanthroline.

The adhesive composition for additive printed wiring boards of the present invention is characterized in that at least one compound selected from the group consisting of benzimidazole compounds, benzotriazole compounds, and 0-phenanthroline compounds is used in combination with the mercaptotriazine compound. However, the amount of these compounds must be 0.1 to 10 parts by weight. That is, the blending amount is 0.
If it is less than 1 part by weight, the above-mentioned remarkable effect of suppressing copper migration lacing cannot be obtained, and if it exceeds 10 parts by weight, other plating properties such as beer strength and solder heat resistance will be adversely affected.

By containing the mercaptotriazine compound, the adhesive composition for additive printed wiring boards of the present invention has the following properties:
The mercapto group reacts with the copper surface of the circuit and stabilizes it.
It is thought to suppress the occurrence of copper migration, capture ionized copper, and reduce the migration speed.
As a result, it is thought that a remarkable effect of suppressing copper migration is achieved. On the other hand, at least one compound selected from the group consisting of benzimidazole compounds, benzotriazole compounds, and 0- to nanthroline compounds, which is used in combination with the mercaptotriazine compound, mainly chelates ionized copper to suppress copper migration. It is considered that

Hereinafter, the effects of the present invention will be specifically explained using Examples and Comparative Examples.

A composition having the formulation shown in Table 1 was dissolved in methyl ethyl ketone (MEK) to prepare a solution with a solid content of 30%.

The above MEK solution was coated on a glass-epoxy substrate using a barcoder to a dry film thickness of 35 μm, and cured at 150° C. for 2 hours.

This was roughened at 40°C for 10 minutes using a chromic acid solution (Cr0360 g/l, concentrated sulfuric acid 230++ lm0), and then subjected to surface activation treatment with a colloidal solution of palladium chloride.Furthermore, electroless copper plating ( After electrolytic copper plating (film thickness: 3 μm) and electrolytic copper plating (film thickness: 32 μm), heat treatment was performed at 120°C for 2 hours.The obtained sample was line/space-coated using a solvent-developed dry film resist and a ferric chloride solution. Comb-shaped electrodes of =0.5 mm and 10.5 mm were obtained.The following copper migration evaluation and plating physical property evaluation were performed on these comb-shaped electrodes, and the results shown in Table 2 were obtained.

Migration amount: 107℃, 9 in a pressure Kutzker tester
A direct voltage of 100 V (D
C) was applied for 8 hours, and the area between the electrodes was observed with a microscope before and after the application, and the insulation resistance between the lines was measured. The inter-line insulation resistance was measured after applying DCtoov between the electrodes for 1 minute.

90° beer (peel strength and normal soldering heat resistance (260°C)) according to JIS-C6481.
was measured and evaluated.

Comparative Example 1.2 A comb-shaped electrode was prepared in the same manner as in the example by changing the blending amount of the additive in the adhesive composition used in the example as shown in Table 2, and the above-mentioned copper migration evaluation and plating physical property evaluation were performed. I did it. The results are shown in Table 2.

〔Effect of the invention〕

According to the present invention, in addition to a mercaptotriazine compound, at least one compound selected from the group consisting of a benzimidazole compound, a benzotriazole compound, and an o-phenanthroline compound is used as an adhesive for additive printed wiring, respectively. By incorporating it into the adhesive composition, copper migration can be suppressed without affecting the basic physical properties of the adhesive composition, and the insulation resistance of the wiring board of the product can be prevented from decreasing. High-density wiring can be achieved.

Agent: Patent Attorney Nobuo Kogawa -

Claims (1)

[Claims] 0.1 to 10 parts by weight of a mercaptotriazine compound and 0 to 100 parts by weight of a mixture of rubber and thermosetting resin.
．． An adhesive composition for an additive printed wiring board, which contains 1 to 10 parts by weight of at least one compound selected from the group consisting of a benzimidazole compound, a benzotriazole compound, and an o-phenanthroline compound.