Scanning probe anodization: Nanolithography using thin films of anodically oxidizable materials as resists

We report scanning probe microscope (SPM) nanolithography that uses thin films patternable by scanning probe anodization as resists. An organosilane monolayer composed of trimethylsilyl [-Si(CH3)(3)] groups was prepared by chemical vapor deposition on a Si substrate. It was then patterned through the localized degradation of the monolayer as a result of anodic reactions induced beneath a SPM tip. The fabricated patterns on the resist were transferred into the substrate Si by area-selective chemical etching in an aqueous NH4F/H2O2 solution. Consequently, grooves narrower than 100 nm were successfully fabricated. We have also developed another resist system for SPM lithography that is compatible with a wide range of surfaces, including insulators. The resist consisted of a thin Ti film covered with a fluoroalkylsilane monolayer. The monolayer was degraded along a tip-scanning trace. This patterned resist was etched in a dilute HF solution. The chemical etching of the underlying Ti him proceeded selectively in the region where the monolayer had been degraded, and the pattern was transferred into the Ti resist film. (C) 1996 American Vacuum Society.