| 摘要 |
In etching an organic insulating layer made of a polyimide film, a polyimide containing at least a recurrent unit expressed by general formula (1) is used for the polyimide film: ; and an alkaline etchant containing oxyalkylamine, a hydroxide of an alkaline metal compound, water, and preferably an aliphatic alcohol is used as an etchant. The composition enables efficient formation of desirably shaped via holes and through holes through the organic insulating layer on a wiring board.
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