摘要 |
PROBLEM TO BE SOLVED: To eliminate tarnish on a metal foil surface by introducing a cathode- electrolysis treatment in a photoresist removing process, for the leads formed on the insulating film. SOLUTION: Adhesive material is applied on a single surface of a polyimide film 1, on which punching work is made to prepare device holes 5, outer holes 6 and sprocket holes 7, and copper foil is pasted. Then, leads 4 of specified patterns are formed by etching the copper foil using photoresist layer as masking material. After immersing in a first bath that contains sodium hydroxide solution, cathode-electrolysis treatment is applied in a second bath that contains electrolytic solution of sodium hydroxide containing nonionic surface-active agent. Consecutively, the photoresist layer and a backside protecting resist layer are removed by immersing in a third bath that contains hydrosulfric acid cleaning solution.
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