EB (electron beam) resist is widely used for the EUV (extreme ultraviolet) mask production. Tighter pitch size and smaller pattern features are required on EUV mask for the next generation EUV patterning. One of the most critical issues for EB lithography process is the stochastic issue which is induced by low density of quanta due to high energy of e-beam exposure. Such stochastic can induce the heterogeneity of various reactions in the photoresist. As a result, serious performance degradation is caused in key lithographic areas such as LWR (line width roughness) and resolution. It’s well known that quanta stochastic can be reduced by high dose condition. Thus, demand of high dose EB resist has been risen for further performance improvement. However, it's also well known that the side-reaction, such as cross-linking, is occurred in the photoresist using PHS (polyhydroxystyrene) based polymer on the high dose e-beam condition. In this study, several positive-tone chemically amplified resist (pCAR) formulations with the different materials were studied under Point-beam conditions to investigate the cross-linking influence on lithographic performance.
|