| 摘要 |
PROBLEM TO BE SOLVED: To provide a film carrier tape for mounting electronic component which hardly forms scooped parts and to prevent occurrence of whiskers in a wiring pattern under solder resist. SOLUTION: In a film carrier for mounting electronic components, a copper foil is stuck to an insulating film, copper foil is etched and a desired wiring pattern is formed. Then, substantially the entire wiring pattern is tinned. Thus, a copper diffused tinning layer (a) is formed, and a protective layer formed of the cured body of solder resist is formed at a prescribed position except for the terminal part of the wiring pattern. The terminal part has the copper diffused tinning layer (a) and a region comprising copper/tin, where copper diffused concentration drops gradually from the surface of the copper diffused tinning layer (a) to the surface of a pure tinning layer (b). The region is substantially and continuously formed with the pure tinning layer (b).
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