High resolution polymer pattern fabrications with Low energy proton beams

Abstract

Low energy protons in several keV energy range have very limited penetration depths into polymer films. This necessitates uses of very thin oxygen etch barrier layers and of dry image developments in oxygen reactive ion etching. For negative tone images the etch barrier layers were deposited patternwise in proton beam induced polymerizations of organo-metallic compounds, followed by dry image developments in oxygen reactive ion etching. For positive tone images the etch barrier layers were deposited prior to patternwise exposures to proton beams on top of polymer films by plasma polymerizations of organo-metallic compounds, or by evaporation or sputtering of certain metals. Hydrogen atoms and/or protons react with metal atoms in the etch barrier layers to yield volatile metal hydrides, making the exposed areas more vulnerable to oxygen reactive ion etching, and providing positive tone images after image developments. In these processes almost any kind of carbonaceous polymer films can be used as imaged materials. With a bright ion source available the exposure times could be less than a second, yielding high aspect ratio and high resolution polymer patterns.