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Abstract

A method is disclosed for forming openings in polyimide layers and for thereby forming semiconductor devices. The method allows for the forming of openings having tapered side walls and precise dimensional control. First and second layers of polyimide are sequentially formed on a surface. The first layer, in contact with the surface, is fully cured while the second layer is only partially cured. Overlying the second layer is a masking layer which can alternatively be an inorganic material or a resist material. A pattern is formed in the masking layer to expose portions of the upper polyimide layer. The pattern includes openings of predetermined size having a precise critical dimension. Using the patterned masking layer as an etch mask the upper layer of polyimide is isotropically etched in an etchent which etches the partially cured polyimide but which does not etch the fully cured underlying polyimide. The underlying polyimide layer is then anisotropically etched using the patterned masking layer as an etch mask to form openings in the cured polyimide layer having the same critical dimensions as in the masking layer pattern. The masking layer is then removed and the second polyimide layer is fully cured.

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First Claim