A resist material study for LWR and resolution improvement in EUV lithography

It had been reported that LWR and resolution were improved according to loading amount of quencher along with a decrease of sensitivity. Influences of quencher and PAG anion size on acid diffusion in acetal protected PHS-based polymer were examined and it was found that acid diffusion length is mainly controlled by quencher, resulting in the improvement of LWR and resolution as well as the decrease of sensitivity by way of reducing acid diffusion length. In order to compensate for the sensitivity loss, we investigated the effect of PAG structures and properties on acid generation and it was found that acid generation efficiency increased with the reduction potential of PAG. In this paper, we discussed how to solve the dilemma among sensitivity, resolution and LWR in EUV lithography, by applying high-efficiency PAG under high quencher concentration.