JPH0745716B2 - Resist ink for electroless plating - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resist ink used when a printed circuit board is manufactured by electroless plating.

(Prior Art and Problems) Conventionally, as a resist for electroless plating, for example, a two-component composition including a main agent containing an epoxy resin, an inorganic filler and an organic solvent, and a curing agent containing an aromatic polyamine compound and an organic solvent. Mixed type resist inks are known.

The conventional products have reached quite high performances in terms of chemical resistance, adhesion to substrates, and heat resistance, but their performance is not yet sufficient. In particular, the following drawbacks have been pointed out with respect to conventional products.

The viscosity of the ink, especially thixotropy, tends to change, making it difficult to obtain stable printability.

When screen-printing, pattern reproducibility is not sufficient and it is difficult to deal with fine patterns. Ie about
When the pattern has a line width of 200 μm, its reproducibility is insufficient.

The chemical resistance of the cured resist film is still insufficient under the recent severe chemical treatment conditions.

During the electroless plating process, copper is also likely to be deposited and adhered on the plating resist, so that the so-called "copper swing" phenomenon is likely to occur. The growth of the deposited copper causes a short circuit between the lines.

The present inventors previously developed a resist ink for electroless plating that overcomes these drawbacks and applied for a patent (Japanese Patent Application No.
-308926).

This resist ink was satisfactory, but subsequent studies revealed that cracks tended to occur in the fine pattern when various stresses were applied during the manufacturing of the substrate. It was newly requested.

(Object of the Invention) In order to meet the above-mentioned demands, the present invention aims to provide a resist ink which does not cause cracks in a fine pattern and has good chemical resistance and non-copper freeness. Is.

(Structure of the Invention) The present invention is as follows.

The following components [A] to [F] [A] Phenol novolac type epoxy resin [B] Aliphatic polyol polyglycidyl ether [C] Phenol novolac resin [D] Montmorillonite organic complex, [E] Thermosetting reaction accelerating catalyst [F] ] A resist ink for electroless plating containing an organic solvent.

The present invention having such a structure has been completed based on the following findings obtained by the present inventors.

In order to prevent the occurrence of cracks in the fine pattern, it is basically important that the resin forming the resist film has flexibility.

In order to improve the chemical resistance of the resist film and to prevent the copper spattering phenomenon on the resist film, it is basically important to improve the chemical resistance of the resin forming the resist film.

When the resin forming the resist film has flexibility, chemical resistance is generally lowered.

By using the specific combination component of the present invention, particularly the aliphatic polyol polyglycidyl ether, cracking and copper fringing can be effectively prevented.

Hereinafter, the configuration of the present invention will be described in detail.

Component [A] Phenol novolac type epoxy resin is a phenol novolac resin obtained by condensing phenols such as phenol, cresol and bisphenol A with formaldehyde in the presence of an acidic catalyst, and in the presence of an alkali catalyst. It is obtained by reacting with epichlorohydrin, and preferably has an epoxy equivalent of 170 to 250.

Specific examples thereof include Epicoat 154 (produced by Yuka Shell Epoxy Co., Ltd.).

Component [B] Aliphatic polyol polyglycidyl ether is obtained by reacting polyols such as (poly) ethylene glycol, 1,6-hexanediol and trimethylolpropane with epichlorohydrin in the presence of an alkali catalyst. Preferably, the epoxy equivalent is 100 to 400.

Specifically, (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-
Examples thereof include hexanediol diglycidyl ether, (poly) glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, and halides thereof. Epolite 80MF (manufactured by Kyoeisha Oil and Fat Chemical Co., Ltd.) and the like are commercially available products.

Component [C] The phenol novolac resin is obtained by condensing phenols such as phenol, cresol, bisphenol A and formaldehyde in the presence of an acidic catalyst, and preferably has a hydroxyl equivalent of 100 to 150 and a softening point. 60 ~ 13
It is at 0 ° C.

A specific example of a commercially available product is BRG-556 [Showa Highpolymer Co., Ltd.].

Component [D] Montmorillonite organic complex is a complex of montmorillonite and an organic substance, and as commercially available products, Orben [manufactured by Shiraishi Industry Co., Ltd.], New D Olben [same as above], Sben [Toyojun Hiroyuki] Co., Ltd.] and the like.

The component [E] catalyst for accelerating thermosetting reaction has a function of accelerating the thermosetting reaction of the epoxy resin [A] and the phenol novolac resin [B].

Specific examples include 2-methylimidazole, 2-phenylimidazole, 2-heptadecylimidazole, 2-undecylimidazole, 2-ethyl-4-methylimidazole, 2,4-dimethylimidazole, 2-isopropylimidazole, 2-phenyl. -4-Methylimidazole and the like can be mentioned. Further, triphenylphosphine, 1,8-diaza-bicyclo (5.4.0) undecene-7, or a phenol salt thereof, 2-ethylhexanoate, carbonate or the like can be used.

Component [F] The organic solvent is the epoxy resin of component [A] and component [B].
It dissolves the phenol novolac resin of (1), and preferably at a temperature (usually 150 to 2
It has a relatively high boiling point because it is performed at 50 ℃.

Specific examples include cellosolves such as ethyl cellosolve, butyl cellosolve and phenyl cellosolve, acetate esters thereof, carbitols such as ethyl carbitol, butyl carbitol and phenyl carbitol, and aralkyl alcohols such as benzyl alcohol. be able to.

These may be used alone or in combination of two or more.

The organic solvent used for the main agent and that used for the curing agent system may be the same or different.

The content of each component in the present invention is preferably as follows.

The component [B] is 10 to 100% by weight with respect to the component [A]. The component [C] is used in such a ratio that the component [C] has 0.5 to 2.0 phenolic hydroxyl groups per one epoxy group of the components [A] and [B]. The component [D] is the component [A],
It is 3 to 25% by weight based on the total amount of [B], [C] and [E]. The component [E] is 0.5 to 10% by weight based on the total amount of the components [A], [B] and [C]. The component [F] is 20 to 80% by weight based on the total amount of the components [A], [B] and [C].

When the resist ink is in the above content range, particularly excellent performance can be exhibited. Especially component [B]
The aliphatic polyol polyglycidyl ether is 10 to 10
When it is in the range of 0% by weight, an excellent resist ink having both clutch resistance and chemical resistance and reproducible screen printability can be obtained.

When the content of the component [B] is less than 10% by weight with respect to the component [A], it is difficult to obtain flexibility, and 100% by weight.
If it exceeds, the chemical resistance tends to decrease.

In the present invention, in addition to the above components [A] to [F], other components may be blended if desired.

For example, a blue pigment, a green pigment, carbon black or the like can be appropriately mixed as a colorant to facilitate the identification of the resist film. The content of the colorant is usually in the range of 0.5 to 10% by weight with respect to the components [A] to [E].

The resist ink of the present invention is preferably produced by separately preparing the main component and the curing agent system as described below, and then mixing both.

[Main agent]

Phenol novolac type epoxy resin is heated to about 50 ~ 120 ℃, fluidized and weighed a predetermined amount, and then added a predetermined amount of aliphatic polyol polyglycidyl ether, organic solvent and montmorillonite organic complex, dissolver etc. Mix evenly. After cooling the obtained mixture to room temperature, the fillers are well mixed using a kneading machine such as a three-roll mill, dispersed to form an ink, and finally a predetermined amount of an organic solvent is appropriately added as necessary, and the dissolver is added. And the like to mix them well to form the base compound having a predetermined viscosity.

As described above, the montmorillonite organic composite of the filler used in the present invention is preferably added to the main agent, but it is not necessarily limited to this, and in some cases, it is added to the curing agent system. It is also possible to use.

[Curing agent system]

Separately from the main component, a phenol novolac resin is usually added to an organic solvent previously heated to about 50 to 130 ° C. while stirring to be dissolved, and then a thermosetting reaction accelerating catalyst is added to homogenize the curing agent. System.

The main component and the curing agent system prepared as described above are weighed out and thoroughly mixed with a stirrer or the like to be homogenized to produce a resist ink.

The heat curing reaction accelerating catalyst is usually added and mixed in advance in the curing agent system, but otherwise, for example,
Prepared as a solution of the catalyst dissolved in an organic solvent,
This catalyst solution can be added at the same time when the ink is produced by mixing the main agent and the curing agent system.

In the case of producing a resist ink by mixing a main agent and a curing agent system, the amount of each is such that the phenolic hydroxyl group of component [C] is equivalent to one epoxy group of components [A] and [B].
It is preferable to use 0.5 to 2.0, preferably 0.8 to 1.2. When used in this range, the cured resist film has good crack resistance, heat resistance and chemical resistance.

(Effects of the Invention) As is clear from the results of Table 3 below, the resist ink of the present invention is excellent in crack resistance, chemical resistance, and non-copper-freeness, and is an electroless plating having these characteristics. It is extremely useful as a resist for use.

(Examples and Comparative Examples) Examples 1 and 2 and Comparative Examples 1 and 2 Main ingredients [a] to [d] were prepared according to the formulations shown in Table 1. Separately, a hardener system was prepared according to the formulation shown in Table 2. A resist ink was manufactured by blending each of the obtained main components and each curing agent system in a combination shown in Table 3.

When the characteristics of this resist ink were examined, the results shown in Table 3 were obtained.

The method of measuring the characteristics is as follows.

[Crack resistance] Line width 150μ, thickness 2 on ACL substrate (100mm × 500mm × 1.0mm)
After screen-printing at 0μ and curing (150 ° C, 30 minutes), the substrate is warped in the longitudinal direction so that the center is 200 mm above both ends, and it is measured whether cracks occur.

[Chemical resistance and copper content]

After curing the resist pattern printing, further chemical roughening,
Electroless plating treatment, chemical resistance to chemical roughening solution, and number of copper particles observable with 20 times loupe (per 1 cm ² ).
Was measured as the amount of copper.

[Notes (Tables 1 and 2)] (1) Yuka Shell Epoxy Co., Ltd. phenol novolac type resin, epoxy equivalent 176 to 181 (2) Kyoeisha Oil and Fat Chemical Co., Ltd. glycerin diglycine ether, epoxy Equivalent 140-170 (3) Kyoeisha Yushi Kagaku Kogyo Co., Ltd. trimethylolpropane triglycidyl ether, epoxy equivalent 135-1
65 (4) Shiroishi Industry Co., Ltd. montmorillonite organic composite (5) Mitsubishi Kasei Co., Ltd. carbon black (black pigment) (6) Showa Highpolymer Co., Ltd. phenol novolac resin, softening point 80 ° C

Claims (3)

[Claims] 1. The following components [A] to [F] [A] phenol novolac type epoxy resin [B] aliphatic polyol polyglycidyl ether [C] phenol novolac resin [D] montmorillonite organic complex [E] thermosetting reaction Accelerating catalyst [F] A resist ink for electroless plating containing an organic solvent. 2. A component [A] phenol novolac type epoxy resin, [B] aliphatic polyol polyglycidyl ether, [D] montmorillonite organic composite, [F] main component containing an organic solvent, and [C] phenol novolac resin. The resist ink according to claim (1), which comprises: [E] a thermosetting reaction accelerating catalyst, [F] an organic solvent, and optionally [D] a montmorillonite organic complex-containing curing agent system. 3. The resist ink according to claim 1, which contains the component [B] aliphatic polyol polyglycidyl ether in an amount of 10 to 100% by weight based on [A].