| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of applying a plating superior in adhesion to the surfaces of small-size leads of a lead frame for use in an integrated circuit chip. SOLUTION: A continuous piece 20 of a sheet-like base metal is preplated with nickel layers 23a, 23b perfectly covering the base metal, one surface is preplated with a palladium layer 24 of a thickness suited for wire bonding mounting, and the opposite surface is preplated with a palladium or lead-free solder layer 25 of a thickness suited for mounting components. A lead frame structure is die-punched from this sheet, the base metal is exposed at the die- punched ends to reinforce the adhesion to molding compounds. |
