PROJECTION X-RAY-LITHOGRAPHY WITH ULTRATHIN IMAGING LAYERS AND SELECTIVE ELECTROLESS METALLIZATION

Soft x-ray synchrotron radiation, of wavelength 14 nm, is used to patt ern self-assembled monolayer films, which are then selectively metalli zed using electroless deposition. Organosilane precursors of the gener al type RSiX3 (R= organic functional group; X = Cl, OCH3) are used to form covalently bound ultrathin films by molecular self-assembly on Si wafers. These films are approximately one monolayer (approximately 1 nm) thick. X-ray exposure is used to remove or transform the R groups in selected areas of the film. The laterally patterned reactivity on t he surface is then used as a template for the additive deposition of a thin layer of electroless nickel in the unexposed regions. The Ni met al layer can then be used as a plasma etch mask for pattern transfer. Metal features with linewidths less-than-or-equal-to 0.25 mum are prod uced with exposure doses of 50 mJ/cm2.