JPH0374828B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to photoresist stripping compositions with improved stability. 2. Description of the Related Art Printed wiring boards, in which various parts are mounted and connecting wiring is created in the form of wiring diagrams on an insulator, are known in various forms such as single-sided, double-sided, and multilayer wiring boards. When creating patterns for printed wiring boards, when the pattern density is high, a photographic method using a photoresist is said to be preferable to a screen printing method. The photoresist must undergo steps such as exposure, development, and etching, and finally be completely peeled off. A mixture of methylene chloride and methanol described in Japanese Patent Publication No. 52-45241 is known as such a photoresist stripping agent. The performance required of a photoresist stripping agent includes not only high resist stripping ability but also no influence on various materials used in printed wiring boards, especially metal materials. The present invention provides a novel photoresist stripping agent that has little effect on printed wiring board materials and has high stability.The present invention provides a photoresist stripping agent that has little effect on printed wiring board materials and is highly stable. Alternatively, the present invention relates to a photoresist stripping composition characterized in that it contains an amine. The total blending ratio of methylene chloride and alcohol in the photoresist stripping composition of the present invention is suitably at least 90 wt%, preferably at least 95 wt%. If it is less than this, sufficient photoresist peeling ability cannot be obtained. It is preferable to select a blending ratio of methylene chloride and alcohol that is close to an azeotropic composition of the two, but it must be substantially nonflammable, and flammable alcohols should be mixed with chlorides that have no flash point. It is also important to use a small amount relative to methylene. For example, methylene chloride and methanol form an azeotropic composition at a blending ratio of approximately 13:1, and methylene chloride and isopropanol at a blending ratio of approximately 12:1, and are virtually nonflammable and pose no problem, but for ethanol, 95 wt% or more is required. Yes, but rather an azeotropic composition is not preferred. Use at or near an azeotropic composition has the advantage that the composition ratio does not fluctuate greatly during distillation regeneration and that the stripping performance can be kept constant. Usually, the mixing ratio of methylene chloride and alcohol is 7:1.
It is sufficient to set the ratio to ~25:1. Suitable examples of other alcohols include lower alcohols such as n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, and tertiary-butyl alcohol. Two or more of these alcohols may be used in combination as long as they do not impede the object of the present invention. The insulating portion of the printed wiring board is made of a composite material of epoxy resin or phenol resin, paper, glass fiber, or the like. Also, for the surface plating of wiring boards,
Tin-lead plating, copper plating, or gold plating with a nickel base are used. The photoresist stripping agent is required not to have an adverse effect on the various materials constituting these printed wiring boards, and the stripping agent itself is also required not to decompose, especially due to the influence of metals. However, although methylene chloride, which constitutes the main component of photoresist stripping agents, has excellent stripping power, is nonflammable, and has low toxicity, it cannot be distilled and reused in the presence of metals, oil, oxygen, light, or moisture. In some cases, there is a strong tendency to decompose, and stabilization is absolutely necessary. On the other hand, the influence on the material of printed wiring boards is largely due to the acid generated by decomposition of methylene chloride, rather than the methylene chloride itself, and from this point of view as well, stabilization of stripping agents containing methylene chloride is important. The above-mentioned stabilization can be well achieved by incorporating epoxides and/or amines into the release agent of the present invention. Epoxides have at least one adjacent epoxy group in the molecule.

A compound having the formula: specifically propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide,
Epichlorohydrin, styrene oxide, butyl glycidyl ether, phenyl glycidyl ether, glycidol and the like are preferred. Particularly preferred epoxides are epichlorohydrin and propylene oxide. The amount of epoxides added is not particularly limited, but 0.02
A small amount of ~3wt%, preferably 0.05-0.8wt% has a sufficient stabilizing effect. Suitable amines include diisopropylamine, cyclohexylamine, diallylamine, n-methylbenzylamine, N,N-dimethylbenzylamine, N-alkylmorpholine, etc.
Particularly preferred are diisopropylamine, diallylamine, and N-methylbenzylamine. The blending amount of amines is the same as that of epoxides.
There are no particular limitations, and 0.001 in the release agent.
A very small amount of ~0.1wt%, preferably 0.01~0.06wt% may be added, and even if more than this is added, it will only become uneconomical and there will be no significant difference in effectiveness. The stripping agent of the present invention may contain other solvents. For example, by blending 0.2 to 7 wt%, preferably 0.5 to 5 wt% of 1,2-dichloroethane with methylene chloride and alcohol, the stripping performance can be improved. Further, it is possible to increase the peeling speed. Although 1,2-dichloroethane has a flash point similar to that of methanol and isopropanol, it is effective when added in a smaller amount to methylene chloride than these alcohols;
- Addition of dichloroethane can also make it substantially non-flammable. The photoresist that can be removed by the stripping composition of the present invention is not limited in any way, and examples include positive or negative photoresist, deep ultraviolet exposure resist, and X-ray or electron beam resist. . Materials for resists for light exposure include quinone diazide based on phenol and cresol novolak resin, cyclized rubber based on cis-1,4-polyisoprene, polycinnamic acid, etc. Resists include polymethyl methacrylate and polymethyl isopropenyl ketone, and electron beam and X-ray resists include polymethyl methacrylate, glycidyl methacrylate-ethyl acrylate copolymer, and methyl methacrylate-methacrylic acid copolymer. Coalescence and the like are known, but the stripping composition of the present invention is effective for both. The stripping composition of the present invention is particularly suitable for stripping photoresists during the production of printed wiring boards, but is also suitable for other photoresist application fields such as semiconductors,
It is extremely effective as a remover in the field of electronic components such as lead frames and TV shadow masks, as well as in the field of etching metals, ceramics, glass, etc. Examples of the present invention will be described in more detail below. Example 1 [Stability performance] The stripping agent of the present invention was prepared by coexisting iron, moisture, and oxygen, heating under reflux for 7 days under light irradiation, and measuring the condition of the iron piece and the pH of the liquid after stability performance evaluation. The stability performance was evaluated. The results are shown in Table 1. Condition of the iron piece ◎...No change in the surface ○... Part of the surface is cloudy △... About 50% cloudy ×... Fully cloudy or partially rusted

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Claims (1)

[Claims] 1. A photoresist stripping composition comprising a photoresist stripping agent containing methylene chloride and alcohol as essential components, and epoxides and/or amines added thereto.