Dependence of process parameters on planarization isolation and etching of sloped vias in polyimides for GaAs ICs

The effect of imidization condition for realizing sloped vias in polyimide film using positive resist as an etch mask has been investigated. Using chemical etching techniques, vias of tapered angles ranging from 45° to 60° has been obtained for 80-percent imidization of the polyimide film. Results on optimum process conditions for obtaining dielectric breakdown strength of 2MV/cm and degree of planarization of about 58 percent have also been included.