Single pulse laser removal of indium tin oxide film on glass and polyethylene terephthalate by nanosecond and femtosecond laser

Indium tin oxide (ITO) is the most important transparent conducting electrode to date and the candidate for ultrafast signal processing in telecommunication region. ITO is normally selectively removed in a multiple-steps process for device application. In this work, we aimed to study single pulse removal of ITO-coated glass and PET by using a nanosecond (ns) laser (266 nm) and a femtosecond (fs) laser (1,025 nm) where each process is dominated by either linear or nonlinear process. For ns laser, ITO was removed from PET substrate at 0.01 J/cm2. Detachment likely occurred via thermal-induced process because of the high absorption by both ITO and PET and the thermomechanical properties of PET. At higher laser fluence (∼0.04 J/cm2), the ITO films on both substrates were damaged, and at 1.34 J/cm2, ITO was ablated from the glass substrate. For fs laser removal via nonlinear process, ITO was removed from PET substrate at 0.3 J/cm2, but at 0.8 J/cm2, the PET substrate was also modified. ITO layer was partially removed from glass substrate by fs laser pulse at 0.3 J/cm2 and full removal only occurred at 1.7 J/cm2. Thus, the fluence range for single fs pulse removal of ITO/PET was 0.3–0.8 J/cm2 and >1.7 J/cm2 for ITO/glass.