| abstract |
PROBLEM TO BE SOLVED: To prevent substitution deposition of bismuth on the surface of tin or a tin alloy anode during plating in a lead-free acidic tin-bismuth alloy electroplating bath. SOLUTION: Diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, triethylenetetraminehexaacetic acid, N, N-dicarboxymethyl-L-glutamic acid, N, N-dicarboxymethyl-L-aspartic acid, hydroxyethylidene diphosphonic acid Nitrilotris (methylenephosphonic acid), phosphonobutanetricarboxylic acid, hydroxyethylaminodimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, N, N-dicarboxymethyl-L-alanine, hydroxyethyliminodiacetic acid, 1,3 A lead-free acidic tin-bismuth alloy electroplating bath to which a complexing agent selected from diamino-2-hydroxypropanetetraacetic acid, mercaptosuccinic acid, and salts thereof is added. A specific type of aminocarboxylic acid or phosphonic acid is selectively added. [Selection figure] None |