Surface roughness development on ArF-photoresist studied by beam-irradiation of CF_4 plasma

摘要

We report an observed relationship between chemical modifications and physical morphological roughness on a photoresist for ArF excimer laser photolithography in fluorocarbon plasma beam irradiation. At the very beginning period, three stages of characteristics of chemical changes occurred upon surface roughening or wrinkling of the photoresist; (1) a rapid reduction of C = O bonds, (2) gradual formation of a fluorocarbon layer, and graphitic (sp ~2-C) or amorphous (sp~3-C) carbon layer; (3) as elapsed incubation phase, i.e. lag, where reached a steady state of chemical changes for fluorocarbon ion irradiation on the surface; finally morphological changes initiated. Those processes evolved within dose of 6 × 10~(15) cm~(-2) for ion energy of a few hundred eV.