EUV exposure is crucial to evaluate EUV resists but there are currently a limited number of EUV exposure tools available worldwide. Therefore, an alternative exposure method should be considered to accelerate EUV resist development. To design materials for EUV resist, it is useful to identify and characterize acid generation mechanisms under EUV exposure. To do this, a performance comparison under EUV, EB and KrF exposure was performed to gather information about the acid generation mechanism during EUV exposure. In this paper, the performance of chemically amplified resists under EUV, EB and KrF was compared regarding sensitivity, LWR and pattern-profile not only to consider alternative exposure methods but also to elucidate the acid generation mechanism under EUV exposure. Regarding sensitivity, good correlation was observed between EUV and EB exposure, however, in regard to LWR and resist pattern profile, poor correlation was observed between EUV and EB exposure, and between EUV and KrF exposure. As a result, alternative exposure methods could be used only for basic evaluation and it was determined that EUV exposure was necessary for EUV resist development using chemically amplified resist. From the correlation of sensitivity between EUV and EB exposure, it is suggested that the main acid generation mechanism under EUV exposure was ionization.