Theoretical and experimental investigation of continuous-wave laser scribing on metal thin film: effect of power.

In this paper, the scribing of the metal thin film using a continuous-wave laser is investigated theoretically and experimentally. We propose a reversible relation between incident fluence and ablation width. Microscopic analysis of the results is compared to theoretical expectations. Scribing has been done by focusing a 450 nm laser diode beam on 100 nm chromium thin film. Beam power and scanning speed are varied in the domains of 0.02-1.0 W and 0.05-5 mm/s, respectively. The microscopic images of the thin film show that the average ablation width on metal thin film varies slightly by increasing the scanning speed, which was anticipated by theory. Moreover if scanning speed increases, the ablation quality is reduced significantly and is not compensated by increasing incident power. According to microscopic images of the sample, this method could be a good substitute for pulsed-laser scribing in many applications such as making solar cells.