Formation of dissolution-resistant top layer in EUV-CAR resist and possible impact on line edge roughness

For EUV lithography the line edge roughness is a critical feature for successful patterning. Conditions to minimize line edge roughness stemming from photon, conversion and deprotection stochasticity [1], and molecular interactions [5] have been undertaken. The premise in [1] has been that increasing dose, and simultaneously the amount of base quencher would decrease the line edge roughness. This expectation has not materialized thus far [4]. Here a novel source of stochasticity underlying the line edge roughness is hypothesized and made plausible by modelling. In particular, the formation of a dissolution resistant top layer is discussed and the consequences for the line edge roughness are outlined.