X-ray Chemical Reactions of Novolac Diazonaphthoquinone Resists

Model cresol novolac resins and photoactive compounds (PAC) based on polyhydroxybenzophenones were prepared according to known procedures. The components and resists formulated from them were exposed to X-rays from Aladdin, the electron storage ring at the University of Wisconsin. The loss of azide functionality and the conversion of PAC to acid or ester was monitored by FTIR difference spectrometry. The energy dependence of the sensitivity of conversion of diazonaphthoquinone to ketene was followed by monitoring the loss of diazide when exposed to synchrotron radiation. The effect of PAC functionality on the sensitivity and chemical pathways was studied. The relationship of structure and photon energy to lithographic performance are explored. We discuss the applicability of synchrotron radiation as an exposure source and FTIR as an analytical tool for the study of X-ray resist mechanisms.