| 摘要 |
PROBLEM TO BE SOLVED: To prevent softening at normal temperature and withstand long-term storage while keeping such a state where high flexural property due to recrystallization can be given.SOLUTION: A rolled copper foil is used for a flexible printed wiring board and contains oxygen (O), sulfur (S), silver (Ag), and iron (Fe) with predetermined concentrations. The rolled copper foil is subjected to hot rolling step at predetermined temperature, and a specified value Tdefined by formula, T=-98[O]+1840[S]+2005[Ag]-824[Fe]+0.012Tr, is 9.8 or more (where [E] is the concentrations (mass%) of elements E included in the rolled copper foil, and Tr is temperature (°C) in the hot rolling step). |
