Abstract: This paper presents some methods for the investigationof delay time I$-3$/ induced effects typical of anadvanced acetal-based photoresist, and strategies toimprove the latent image stability. Dissolution ratemonitoring was used to investigate the increasingformation of a surface inhibition layer with extendedintervals I$-3$/. The impact of certain additives, theapplication of a protective coating (AZ$+R$/ Aquatar),and modified process conditions on the inhibition layerwere studied in detail. The photoacid induced acetalcleavage was monitored by UV-spectroscopy (248 nm).Upon KrF excimer laser irradiation the resistabsorbance increases, due to the progressing formationof a strongly absorbing aldehyde fragment. SEM picturesconfirm a linear relationship between the efficiency ofthe acetal cleavage and acid diffusion into unexposedresist areas. Acid evaporation during PEB wasdetermined by a novel method, the so-called Sandwich`Blue' Test. Interpretations of the experimentalresults and some optimization strategies are given. !31
展开▼
