Studies on the interfacial etching reaction of development-free vapor photolithography

Abstract

Development-free vapor photolithography (DFVP) is an all-dry pattern transfer technique, which is based on the reaction of SiO2 with HF vapor under a polymer film in the presence of catalysts, called accelerators, at a temperature above 100 °C. This article reports that both organic bases and superacids can catalyze this interfacial etching reaction. When organic bases are used as the accelerator, the etching mechanism is bimolecular nucleophilic substitution (SN2), while the superacid-catalyzed etching reaction undergoes a unimolecular nucleophilic substitution (SN1) mechanism. Insight gained from this study provides guidance for the development of more sensitive accelerator systems. Now, this novel microlithographic technique is being successfully applied to the manufacture of power electronic devices.