Behavior of Si-Si Bond Oxidation by Electron Beam Lithography

Lithography using siloxane polymers is reasonable for process reduction compared to mask etching process. Generally, crosslinkable groups, such as acrylates and epoxides, and protecting groups are added to siloxane polymers for lithography. We synthesized polydiphenylsilane without those functional groups, and the thermal behavior of that was observed with TG-DSC-MS. The thermal elimination of phenyl group from polydiphenylsilane was observed and the thermal weight loss until 500 °C was under 3%. The polysilane film was directly imaged with EB nano melting apparatus (ENF-3500) and line width of pattern was 12.9 μm. The film thicknesses before and after development were same. The partial heating by EB irradiation caused oxidation of polydiphenylsilane after elimination reaction of phenyl group and cleavage of Si-Si bond by XPS analysis.