0.2 MU-M HOLE PATTERN GENERATION BY CRITICAL DIMENSION BIASSING USINGRESIN OVERCOAT

A method of generating very small hole patterns by introduction of tra nsfer bias into a resist pattern after original resist pattern generat ion has been developed and evaluated. Introduction of transfer bias wa s carried out using a resin overcoating and strippig process and a nov olak resist pattern was used as the original hole pattern. Tire overco ating resin used was polymethylmethacrylate (PMMA) and transfer bias w as introduced by intermixing of novolak resin and PMMA during the PMMA baking step. From scanning electron microscope (SEM) observation, it appeared that 0.20 mu m hole pattern generation was possible by i-line lithography. The amount of undersize was controllable by PMMA Lake te mperature, and 0.06-0.15 mu m undersize could be achieved by using a b ake temperature range of 60-120 degrees C. From results of etching SiO 2 substrate using overcoat treated hole pattern, it appeared that the mixinglayer functioned as an etching mask for oxide film.