Tri-level resist process for fine resolution photolithography

Abstract

A multilayer photoresist system for defining very small features on a semiconductor substrate relies on forming a planarization layer directly over the substrate. An image transfer layer is formed over the planarization layer, and a photoresist imaging layer formed over the image transfer layer. The image transfer layer comprises an organic or inorganic resin which has been cured in a non-oxidated plasma. It has been found that such a curing technique provides a particularly smooth and defect-free image transfer layer. Very thin photoresist imaging layers may thus be formed over the image transfer layer, allowing very high lithographic resolution in the imaging layer. The resulting high resolution openings may then be transferred downward to the image transfer layer and planarization layer by etching, allowing the formation of very small geometries on the substrate surface.

Dependencies are inferred from the claim text.