| 摘要 |
PURPOSE:To obtain a treated surface having no residual deposit and well wettable with solder when a precipitation strengthening Cu alloy is surface- treated with an acid-peroxide treating soln., by adding a soluble fluoride to the treating soln. so as to prepare a specified compsn. CONSTITUTION:A precipitation strengthening Cu alloy for a lead frame contg. 0.1-5wt.% precipitation alloying element is surface-treated with a treating soln. prepd. by dissolving 10-500g/l acid, 1-200g/l peroxide and 1-50g/l soluble fluoride in water. The soluble fluoride is a fluorine compd. soluble in an acid-peroxide treating soln. and may be HF, NH4HF2, NH4F or HaF. The soluble fluoride liberates F-ion and is effective in decomposing and dissolving a deposit. When the concn. is <1g/l, the effect is not satisfactorily produced. In case of >50g/l, the effect is not enhanced any more and the velocity of dissolution is remarkably reduced. |
