Proximity x-ray lithography of siloxane and polymer films containing benzyl chloride functional groups

Silicon wafers coated with films of (p-chloromethyl)phenyl-trichlorosilane or spun coated polyvinyl benzyl chloride were exposed at the University of Wisconsin synchrotron x-ray source using 0.9385 nm radiation (800 MeV) at d oses ranging from 50 to 1500 mJ/cm(2). Exposure resulted in changes to the surface energy and chemical reactivity of the films. The loss of chlorine a nd formation of oxidized carbon photoproducts upon exposure was followed as a function of-dose using x-ray photoelectron spectroscopy A corresponding change in surface energy, as monitored by static water contact angle, was a lso observed. The selective chemical grafting (reductive amination) of amin e ligands to the portions of the siloxane and polymer films which have been exposed to proximity x rays definitively establishes the formation of surf ace aldehyde or ketone groups as an important photochemical pathway. The re sulting surface amine was used to covalently bind either a fluorescent tag or a colloidal Pd (II) nanoparticle capable of initiating the selective dep osition of electroless Ni in the irradiated regions of the film. (C) 1999 A merican Vacuum Society. [S0734-2101(99)11704-4].