Amorphous WO3thin 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‐&mgr;m lines and spaces were obtained following dry development in a low‐power CF4plasma. 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.