Synthesis, characterization, and lithographic behavior of methylated poly(4-hydroxystyrene)

The lithographic performance of three component phenolic resists was significantly improved by use of copolymer in place of novolac. A three component system was evaluated which consists of dissolution inhibitor and sulfonium salt in phenolic resin. The contrast curves for the resist (BPABOC) is shown for resist formulated in novolac versus formulation in copolymer. A contrast of greater than 3.0 is observed for BPABOC in copolymer while the contrast in novolac is less than 2.0. Photolithographic image quality is significantly improved also with wall profiles becoming nearly vertical.