EXCIMER-LASER-INDUCED SUB-0.5-MU-M PATTERNING OF WO3 THIN-FILMS

Amorphous WO3 thin films have been deposited in a plasma-enhanced chemical vapor deposition system, and were patterned with a 193-nm excimer laser (one pulse, 10-25 mJ/cm2). Negative-tone, sub-0.5-mu-m lines and spaces were obtained following dry development in a low-power CF4 plasma. The mechanism for laser-induced etch selectivity was studied with angle-resolved x-ray photoelectron spectroscopy. It was inferred from the fluorine photoelectron spectra that the laser induces atomic rearrangements that impede the etch process initiated by fluorine-containing radicals. A possible interpretation is that the rearrangements, which may be partially thermally activated, reduce the volume of the microvoids present in WO3.