Recent Advances in Acetal-Based BUY Resists

Physical and lithographic properties of structurally diverse acetal-derivatized hydroxy styrene polymers are reported. The dissolution and thermal properties of the acetal-blocked-polymers vary with the size of the pendent acetal moiety. The lithographic performance of the resists containing "bulky" acetal-derivatized polymers was found to be superior to those containing non-bulky acetal functionalized polymers. In the cases where the acidolysis products of the bulky acetal-based polymers are non-volatile alcohols, the post-exposure volatilization, film shrinkage and plasma etch resistance were found to be significantly improved. Bulky acetal-derivatized polymers also show excellent thermal and shelf life stability.