Pulsed Laser Assisted Micro-Scribing of Metal thin Films in Air and Underwater Using UV, Visible and Near-IR Wavelengths

A comparative study has been made for micro-scribing of copper and aluminum thin films in air and underwater using 355nm, 532nm and 1064nm wavelengths of a Q-switched Nd3+: YAG laser with 6ns pulse duration. For aluminum in air medium, the channel depth obtained is high for 355nm wavelength, whereas for copper coated on a polyimide substrate, 532nm wavelengths produced higher depth. In underwater scribing, with increase in the pulsed laser energy, the depth of micro channel was increased and remained unchanged at higher energy. The influence of beam profile on the micro channel cross-section has also been discussed. Further, theoretical modeling of the laser-material interaction in air and underwater ambience conditions to estimate the recession rate has been discussed by incorporating the laser ablation temperature measured using the laser induced breakdown spectroscopy technique.