Micropatterning of SiO2 film using organosilicon nanocluster as a precursor

The micropattern of SiO2 film was prepared by the photooxidation of an oganosilicon nanocluster which consists of a three-dimensional Si-core and organic groups on the surface. By UV-irradiation in air, the organosilicon nanocluster film became optically transparent in the UV-vis region. As an intermediate during the photobleaching, a silyl silylene was observed by laser flash photolysis of organosilicon nanocluster. The FT-IR spectra showed the conversion of Si-Si bond to Si-O-Si bond and the elimination of organic substituent during the photooxidation. The XPS spectra of Si 2p region for the photooxidized film at room temperature showed a peak assigned to SiO2 at 103.4 eV. This is in contrast to a quasi-two-dimensional network polysilane which gives a peak of siloxane structure by photooxidation. The difference was explained by considering the three-dimensional Si-Si network structure of onganosilicon nanocluster. The TGA analysis in air showed a rapid weight loss at 164 degrees C, and the weight remained nearly constant up to 1000 degrees C after the thermal oxidation. The micropattern of SiO2 was formed by the UV-irradiation of the organosilicon nanocluster film with photomask and the development using an organic solvent. The transparent micropattern showed excellent dimensional stability up to 500 degrees C. (C) 1999 Elsevier Science S.A. All rights reserved.