Dependence of swelling and dissolution kinetics of poly(4-hydroxystyrene) in alkaline aqueous solution on alkyl chain length of tetraalkylammonium hydroxide

Recently chemically amplified resists are approaching their performance limits due to the fixed development process. In this study, the dissolution, swelling, and impedance change of resist polymers were measured by a development analyzer with a quartz crystal microbalance method. The resist polymer was poly(4-hydroxystyrene) (PHS), the hydroxyl groups of which were partially protected with t-butoxycarbonyl groups. The alkyl chain lengths of tetraalkylammonium hydroxide were varying from methyl to pentyl groups. When the alkyl chain length of TAAH increased from two to three, the dissolution mode markedly changed.