PREPARATION AND PROPERTIES OF SI-CONTAINING COPOLYMER FOR NEAR-UV RESIST .3. MALEIMIDE SILYLSTYRENE COPOLYMER

Poly(maleimide-alt-p-trimethylsilyl-alpha-methylstyrene) (alpha-PMTMMS) and poly(maleimide-alt-p-trimethylsilylstyrene) (PMTMSS) were synthesized for positive / negative near-UV resists in the containing of diazonaphthoquinone sulfonate (DNS). The electron-rich styrenic monomers tend to undergo alternating copolymerization with an electron-poor maleimide monomer. The chain-stiffening effects of the maleimide and alpha-methylstyrene group were responsible for high thermal stabilities. A higher glass transition temperature of 226-degrees-C was found in alpha-PMTMMS. Lithographic positive / negative images were obtained that were stable to temperatures higher than 200-degrees-C. Excellent solubility in aqueous base was observed with PMTMSS at 10.3 wt % silicon content and an oxygen-plasma etching rate of 1 : 12 compared to hard-baked HPR-204. (C) 1993 John Wiley & Sons, Inc.