Abstract: In etching openings in polyimide film, the film is first etched with a basic reagent in its uncured or partially cured state to form the desired openings, and thereafter, the film is cured. However, this will leave a layer of disturbed material surrounding the openings which has absorbed some reagent and will not fully cure and, therefore, not provide topography suitable for reliable interconnection and metal adherence. This disturbed material is removed by a second etch in a basic reagent, following additional curing to a sufficient extent to prevent any etching of the polyimide free of absorbed etchant. Thereby, suitable topography and adherence is provided.