KrF Excimer Laser Resist using 2-diazo-1, 3-dicarbonyl compounds

KrF excimer laser lithography is one of the most exciting technologies for sub-micron VLSI development and manufacturing in recent years. This technology has the capability to fabricate patterns below 0.5micron. Good resist pattern profiles are not obtained using conventional naptho-quinonediazide-novolac resin deep UV resist because of the strong photoabsorption in the resist. In order to solve this problem, new high transparency positive KrF excimer laser resists, STAR-P, have been developed. In this paper the characteristics of several STAR-P series resists are presented. These resists are formulated using Poly(styrene-co-maleic acid half ester) for the base polymer and various 2-diazo-1, 3-dicarbonyl sensitizers. UV spectra, dissolution inhibition characteristics, and exposure characteristics of these resists are discussed. Poly(styrene-co-maleic acid half ester) has a high transmittance of 70% for a 1.0micron thick film at 248nm. As a result these resists have excellent properties; high contrast and high transparency for KrF excimer laser lithography.