| 摘要 |
PROBLEM TO BE SOLVED: To provide a flexible board on which a copper coat layer having high corrosion resistance and insulation reliability is formed, and to provide an etching method excellent in forming a pattern at a wiring part. SOLUTION: A flexible board comprises, on an insulating film, a base metal layer which mainly contains nickel chromium alloy of which chromium is 23-70 wt.% and is formed to a film thickness of 3-40 nm by a dry plating method, and a copper coat layer of film thickness 10 nm to 35μm which is formed on the base metal layer. Using the flexible board, a first etching is performed with an etching liquid containing one kind selected from among ferric chloride, cupric chloride, ammonium persulfate, sulfuric acid, and oxygenated water. After washing in water, a second etching is performed with an etching liquid containing hydrochloric acid and sulfuric acid, to form a pattern of a wiring part. COPYRIGHT: (C)2007,JPO&INPIT
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