Removal of negative-tone novolak chemical amplification resist by use of ethylene carbonate (EC) and propylene carbonate (PC) was investigated. Unlike positive-tone resist, the removal rate of negative-tone resist by these chemicals was found to be easily measurable. The removal rate of resist by both EC and PC decreased with increasing exposure dose because of the increasing degree of crosslinking of the resist. The removal rate by EC was faster than that by PC at the same temperature. EC more readily penetrates the exposed resist than PC because of its smaller molecular size. From Arrhenius plots of removal rate, we found that both high exposure dose and large molecular size of the chemicals lead to high activation energy in the resist removal reaction.