Dynamics of Radical Cation of Poly(styrene acrylate)-Based Chemically Amplified Resist for Extreme Ultraviolet and Electron Beam Lithography

The dependence of the degree of copolymerization on the dynamics of radical cations of resist polymers was studied. The dynamics of radical cations was investigated in a chemically amplified resist polymer system. In this study, poly(styrene-ran-methyl methacrylate) [P(S–MMA)] was used as the base polymer of the resist model compound. It is suggested that radical cations of MMA are predominantly decomposed to be deprotonated immediately before the hole transfer to the styrene unit in P(S–MMA) at a lower styrene mole fraction (<50%). However, the acid yield of the P(S–MMA) decreases to that of PS with increasing styrene mole fraction (>70%). It is thus suggested that the hole transfer from the MMA to the multiple styrene units (n > 3) occurs in P(S–MMA).