2000 Volume 13 Issue 4 Pages 645-649
In this paper, we have shown the importance of acid labile ether protecting groups in the design of high performance 248nm resists with significantly improved etch resistance. Using α-methylbenzyl ether protecting group, we have synthesized and studied partially protected poly(hydroxystyrene) derivative, PHS-MBE. Studies clearly pointed out that methylbenzyl ether protecting group is thermally stable and undergoes acid catalyzed deprotection leading to preferential rearranged products due to electrophilic ring substitution. Such a rearrangement is shown to provide a unique mechanism to reduce/eliminate resist shrinkage and improve lithographic performance and RIE stability.