| 摘要 |
PROBLEM TO BE SOLVED: To efficiently prevent abnormal crystallization of tin immediately after a copper-foil substrate is plated with tin or a tin alloy. SOLUTION: This abnormal crystallization preventive agent in a plating film on a copper-foil substrate contains (A) at least one kind of acid among such inorg. acid as hydrochloric acid and sulfuric acid and such org. acid as org. sulfonic acid and org. carboxylic acid and (B) at least one kind among an ammonium compd. (except peroxo ammonium compd.), ammonia and an amine compd. Since the ammonium compd., etc., act on the copper foil and then the acid functions, the copper foil is subjected to tin or tin alloy plating after the copper foil is contact-treated with the abnormal crystallization preventive agent, and so the abnormal crystallization of tin immediately after plating is effectively prevented.
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