| 摘要 |
PROBLEM TO BE SOLVED: To improve solderability and appearance of an electrodeposition film obtainable from a tin-silver alloy plating bath of a non-cyanide system. SOLUTION: The tin-silver alloy electroplating bath contains (a) at least one aliphatic amino acids and nitrogenous aromatic carboxylic acids and (b) at least one aliphatic sulfides, aliphatic mercaptans, and thiuoureas. Glycines etc., are exemplified as the aliphatic amino acids of (a), picolic acid, 3-amino pyran-2-carboxylic acid, etc., as the nitrogenous aromatic carboxylic acids of (a), 4, 5-trihydroxy-4'-amino diphenyl sulfide, etc., as the aliphatic sulfides of (b), and 2. 6-dihydroxy-2-mercapto pyridine, etc., as the aliphatic mercaptans. A sulfur compound of the component (b) is used as a stabilizer of the silver and further, the components (a), such as the glycines and picolic acids are used in combination, thereby satisfactorily improving the solder wettability and appearance of the tin-silver alloy film. COPYRIGHT: (C)2007,JPO&INPIT
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