| 摘要 |
[PROBLEMS] To provide a process for producing a printed wiring board, which can remove a residual metal among wirings at a low cost in a simple process without side etching of a copper layer and can realize satisfactory insulation reliability even in the case of a micro wiring product, and a printed wiring board produced by the production process. [MEANS FOR SOLVING PROBLEMS] A process for producing a printed wiring board, comprising the step of forming a pattern by etching of a two-layer flexible substrate comprising an insulator film, a substrate metal layer provided directly on at least one side of the insulator film without through anyadhesive and a copper film layer provided on the substrate metal layer, characterized in that the etching is carried out by a method comprising the step of etching the two-layer flexible substrate by a ferric chloride solution or a hydrochloric acid-containing cupric chloride solution, and the step of then treating the two-layer flexible substrate with an acidic oxidizing agent containing a permanganate and acetic acid.
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