Qualification of a spin apply, photodefinable polymer for packaging of automotive circuits

Spin apply polymer coatings can be used in packaging applications as a stress buffer passivation layer for improved device reliability. They can also serve as dielectric and passivation layers in bond pad redistribution circuits for flip-chip packaging. A high T-g, photodefinable polyimide was selected for both applications, due to good chemical resistance and desirable adhesion characteristics to silicon nitride, various molding compounds, aluminum, and to itself. The product exhibited a wide process window, and tapered via slopes were obtained for metalization through minor process modifications.