Fabrication of the Crystalline ITO Pattern by Picosecond Laser with a Diffractive Optical Element

This study presents the fabrication of crystalline indium tin oxide (c-ITO) patterns on glass substrate using laser-induced crystallization followed by chemical etching. In the proposed approach, an amorphous ITO (a-ITO) thin film was transformed into a c-ITO structure over a predetermined area using infrared picosecond fiber laser irradiation with a 500 kHz repetition rate, under a single laser beam or multiple laser beams by diffractive optical elements (DOE). The residual a-ITO thin film was removed by an etchant solution, in order to form a uniform c-ITO pattern. The formation was due to the heat accumulation effect provided by the high-repetition rate of picosecond laser pulses.