Dry-developed organosilicon resists for 193-NM excimer laser lithography

Irradiation of certain organosilicon polymers with a 193-nm excimer laser forms a latent image that contains increased amounts of oxygen. Patterning is achieved by dry development in an HBr plasma, where the oxidized polymer etches more slowly than the unexposed areas. With these polymers as the top layer in a bilayer resist scheme, 0.2 μm resolution has been demonstrated and resist sensitivities less than 50 mJ/cm² have been achieved. Three classes of organosilicon layers have been investigated: polysilynes, polysilanes, in particular poly(phenylmethyl)silane, and a plasma-deposited polymer derived from tetramethylsilane (PPTMS). The PPTMS, when used with plasma-deposited planarizing layers, opens the possibility of an all-dry, cluster-tool-compatible lithographic cycle.