Investigation of possible ArF resist slimming mechanisms

One of the well-known problems the industry faces concerning 193-nm resists is its shrinkage under scanning electron microscope (SEM) measurements. While different phenomena arising from electron-material interaction are assumed to take place (such as cross-linking and scission), the primary mechanism that brings about this shrinkage is still unclear. Three experiments were performed relating to three theories for the primary mechanism that brings about the shrinkage. The first experiment examined how the shrinkage is affected by 193-nm radiation and corresponds to a theory that the electron exposure induces an effect similar to that of 193-nm exposure. The second experiment deals with electron-beam curing, using parameters similar to those used in SEM measurements (curing entails a much lower power density). The third experiment addresses the theory of disassociation of carbonyl bonds in the resist, leading to cross-linking and eventual evaporation of CO2 molecules. The results from the exposure and curing experiments lead us to believe that an exposurelike effect and resist local heating are not good candidates for the primary mechanism. The last experiment shows that slimming is related to the release of carbonyl bonds. (C) 2006 Society of Photo-Optical Instrumentation Engineers.