Deep X-ray and UV lithographies for micromechanics

Abstract

A bilevel photoresist system which uses optical processing only is presented. The photoresist for this work is poly(methyl methacrylate) or PMMA. It is sensitive to X-ray photons and deep ultraviolet radiation. It can be used for spin coating or can be applied by casting and in situ polymerization. This implies that there are at least four possible versions of the deep lithography process. All of them hinge on the availability of a developer with very high selectivity and low stress formation during liquid processing. Deep X-ray and UV lithography (DUVL) results in PMMA definitions with excellent resolution for photoresist thicknesses of up to 10 mu m. It can be extended to 30 mu m or so by a simple process change. The progress reported indicates that DUVL is a viable tool for micromechanics which is accessible without synchrotron access. This process can be used with many metals which can be plated and therefore extends the micromechanics material base considerably.