PHOTOACID GENERATING POLYMERS BASED ON SULFONYLOXYMALEIMIDES AND APPLICATION AS SINGLE-COMPONENT RESISTS

Three sulfonyloxymaleimides (RsOMI), N-(tosyloxy)maleimide (TsOMI), N- (methane-sulfonyloxy) maleimide (MsOMI), and N- (trifluoromethanesulfo nyloxy)maleimide (TfOMI), have been synthesized and used to make novel photoacid generating polymers. The sulfonyloxymaleimides easily copol ymerized with styrene derivatives to give high molecular weight polyme rs having an alternating structure of both monomer units. Terpolymers based on RsOMI and p-(tert-butyloxycarbonyloxy) styrene (t-BOCSt) were prepared for enhancing resist properties such as adhesion to substrat es, solubility in aqueous alkaline solutions, or transparency in the d eep-UV region. The RsOMI copolymers were found to produce correspondin g sulfonic acids (RsOH), TsOH, MsOH, and TfOH, by deep-UV irradiation in the film state. Thus, the polymers having both the RsOMI and t-BOCS t units show the capability of a single-component, chemically amplifie d resist system in the deep-UV region without addition of any photoaci d generator. Positive- and negative-tone images were obtained by expos ure of the polymer films to deep-UV and post-exposure bake followed by development with organic solvents or aqueous alkaline solutions. (C) 1996 John Wiley & Sons, Inc.