Study on Positive–Negative Inversion of Chlorinated Resist Materials

The chlorinated resist materials ZEP520A and ZEP7000 (ZEON Co.) are changed from positive-tone to negative-tone by high dose electron beam (EB) and ion beam irradiation. Here, the reaction mechanisms of the positive–negative inversion induced by EB were attempted to be clarified with ultraviolet–visible (UV–vis) spectroscopy and X-ray photoelectron spectroscopy. The results indicated that dissociative electron attachment would be induced in response to the irradiation dose. For high dose irradiation (>5 mC cm-2), it was suggested that crosslinking would become predominant because of the structural changes in the resists and the lower scission ratio due to the decrease of the chlorine.