Scanning Probe Lithography Using a Trimethylsilyl Organosilane Monolayer Resist

Abstract

A trimethylsilyl organosilane monolayer was applied as a self-developing resist for scanning probe microscope (SPM) lithography under ambient conditions. Both a scanning tunneling microscope and an atomic force microscope with a conductive probe were applied and shown to be effective for this lithography. The resist was prepared on a silicon (Si) substrate by chemical vapor deposition, and was patterned through the localized degradation of the organosilane monolayer induced by scanning an SPM tip while positively (+5∼+10 V) biasing the substrate. The degradation rate was enhanced by increasing the concentration of atmospheric water vapor or oxygen. The patterning mechanism was identified as tip-induced anodic oxidation, i.e., scanning probe anodization. The pattern was transferred to the Si substrate through selective chemical etching in which the degraded monolayer regions served as etching windows. Consequently, fine grooves as narrow as 30 nm could be fabricated.