Formation of SnO2 thin film by pyrolysis of a photo-cross-linked organotinpolymer

Micropatterns of a SnO2 thin film were obtained by lithographic photoirradi ation followed by pyrolysis of thin films of an organotin polymer poly(4-(( trimethylstannyl)methyl)styrene) (1). Irradiation of the polymer thin film by a KrF laser through a photomask followed by development gave a negative pattern of the insolubilized polymer. The following pyrolysis afforded a pa ttern of SnO2 without significant deformation of the pattern except for a r eduction of the film thickness. The pyrolysis of the irradiated film withou t the development also gave a negative pattern of SnO2. The cross-linking o f the organotin polymer caused by the irradiation was necessary both for li thographic processing and for SnO2 formation. In the conversion of the poly mer to SnO2 during the pyrolysis, the cross-linked network seems to encapsu late low molecular weight intermediates, preventing their escape from the p olymer film.