Abstract: Underplating between a metallic plating base and a photoresist deposited reon can be reduced or eliminated by a method of fabricating a microstructure which includes the steps of:(a) depositing a plating base on the adhesion layer;(b) depositing on the plating base a sacrificial layer of a material that reduces or eliminates underplating on the plating base compared to underplating in absence of the sacrificial layer;(c) depositing a photoresist on the sacrificial layer;(d) exposing, developing and removing the exposed photoresist from the substrate to uncover a portion of the sacrificial layer;(e) removing the sacrificial layer portion from the substrate to uncover a portion of the plating base; and(f) depositing a metallic material on the uncovered plating base under the influence of electrical current.

Abstract: 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 tile spectrum of a mercury vapor lamp, where the photoresist layer is a heat-treated arid 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 methyl structure on the substrate.