Deep UV photochemistry and patterning of self-assembled monolayer films

Abstract

Patterned deep UV irradiation of organosilane self-assembled monolayer (SAM) films caused photocleavage of the organic groups in the molecule, and creates alternating regions of intact film and hydrophilic, surface silanol moieties. The exposed regions can undergo a second chemisorption reaction to produce an assembly of SAMs in the same molecular plane. The patterned SAM films can also act as a template for selective build-up of materials in the z-direction. The use of UV patterned silane SAM films as imaging layers for optical lithography has been demonstrated. The exposed films are selectively metallized using electroless deposition to produce a thin metal layer only in the unexposed areas. The film/metal assembly is a highly resistive barrier to reactive ion etching (RIE) for pattern transfer into the substrate. Features to 0.5 μm line width and working transistor test structures have been produced using this process.