Process to Fabricate Thick Coplanar Microwave Electrode Structures.

A process for making thick metal structures on a substrate has the steps of: selectively exposing a thick layer of photoresist disposed on a substrate to ultraviolet radiation including the 350 nm to 450 nm portion of the spectrum of a mercury vapor lamp, where the photoresist layer is a heat-treated and hydrated photoresist layer, to fully pattern the substrate; developing the patterned substrate by contacting the photoresist layer with a photoresist developing solution; exposing the photoresist layer to a plasma for hardening the pattern against thermal flow; hardbaking the photoresist pattern on the substrate; plating the metal onto the patterned substrate using a low current density (J) during at least part of the plating process, making a thick metal structure on the substrate.