CO2 laser patterning of plasma-deposited high T c superconducting thick films

Recent advances in the development of high Tc superconducting thick films have lead the present work to optimize laser etching parameters for patterning thick films for device fabrication. Plasma-deposited superconducting thick films (200–400 μm) of Y-Ba-Cu-oxide materials on polycrystalline alumina and copper substrates were laser etched using a CO2 laser (10.6 μm) in the enhanced pulse mode. Significant spatial nonuniformity of the surface elemental distribution of Y, Ba, Cu, and Al was observed in the underlying laser-etched area. The laser fluence for threshold etching was observed to be 25 J/cm2. An etch rate of 4.0 μm/scan was calculated at an optimized laser fluence of 292 J/cm2 for patterning plasma-sprayed thick films having an estimated heat affected zone of 15 μm. An absorption length of 52 μm for the CO2 laser was determined to be suitable for patterning thick films for device fabrication.