| abstract |
One method of making a bump structure includes forming a passivation layer over a substrate. A metal pad structure is formed over the substrate, with the passivation layer surrounding the metal pad structure. A polyimide layer containing a polyimide is formed over the passivation layer and the metal pad structure. A metal bump is formed over the metal pad structure and the polyimide layer. The polyimide is a reaction product of a dianhydride and a diamine, at least one of dianhydride and diamine containing one of the following group: a cycloalkane, a condensed ring, a bicycloalkane, a tricycloalkane, a bicycloalkene, a tricycloalkene, a spiroalkane and a heterocyclic ring . |