PURPOSE: To facilitate the processing of polyimide resin to shape it finely and steeply, by etching an insulation film, forming a pattern, wet etching a part of the polyimide layer and dry etching the polyimide resin to remove it.
CONSTITUTION: A polyimide resin layer 2 is formed on a semiconductor substrate 1, and an insulation film 3 is formed on the polyimide layer 2. Photoresist 4 is applied thereon and a pattern is formed. The insulation film 3 is removed according to the shape of the pattern. The resin layer 2, masked with the resist 4, is etched with a hydrazine etchant to remove a part thereof. The resin layer 2 is then dry etched and removed with the insulation layer 2 used as a mask. After that, the insulation film 3 is removed. In this manner, the polyimide can be processed easily to shape it finely and steeply.