Lithography and Spectroscopy of Ultrathin Langmuir-Blodgett Polymer Films

摘要

Ultrathin (0.9 - 15.3 nm) poly (methylmethacrylate) (PMMA) and (30 - 40 nm) novolac/diazoquinone films prepared by the Langmuir-Blodgett (LB) technique have been explored as high-resolution electron beam resists and photoresists, respectively. One-eighth micron lines-and-spaces patterns have been achieved in PMMA using the Perkin Elmer MEBES I pattern generation system as the exposure tool. The etch resistance of PMMA films with thicknesses greater than 4.5 nm is sufficient to allow patterning of chromium film suitable for photomask fabrication. One micron lines-and-spaces patterns have been fabricated by optical lithography in 30 nm thick novolac/diazoquinone films, and etched into 50 nm of chromium. Monolayer PMMA films containing 5 mol% pyrenedodecanoic acid (PDA) is a probe were prepared by transfer to a quartz substrate at different surface pressures and characterized by fluorescence spectroscopy. The ratio of excimer to monomer emission intensity (Ie/Im) has a maximum value at 10 dyn/cm, which is suggestive of a structural rearrangement occurring in the Langmuir film at the surface. (aw)