DEEP UV PHOTORESISTS BASED ON POLY(DI-TERT-BUTYL FUMARATE)

Poly(di-tert-butyl fumarate) was prepared and evaluated as a potential candidate as a deep UV photoresist. Although this polymer displayed excellent sensitivity, the polymer was found to exhibit poor dry etch resistance. Copolymers of di-tert-butyl fumarate with either allyltrimethylsilane or styrene, and an onium salt as a photoacid generator were synthesized and subsequently evaluated using a 248-nm KrF excimer laser step-and-repeat system (stepper). At 248 nm, the absorbance of similar to 1 mu m thick resist films was only 0.156-0.211. The sensitivities of these resists were 1-4 mJ/cm(2). The dry etch resistance of these photoresists was comparable to that of conventional positive photoresists based on novolac resins. (C) 1995 John Wiley and Sons, Inc.