Laser Microfabrication of Glass Substrates by Pocket Scanning

Abstract

Precise laser microfabrication of glass is a high challenge task due to the stress-induced micro-cracks generated during laser ablation. In this paper, the results of high quality glass microfabrication by low energy Nd:YAG laser (355 nm, 30ns) ablation and pocket scanning technique are presented. The pocket scanning is to scan the laser beam along parallel overlapped paths with the last path along the structure edge, while the conventional direct scanning is to scan the beam just along the structure edge. It is found that the cracks formed around the edges by pocket scanning are reduced significantly compared to that by direct scanning. Minimum crack sizes of less than 10 μm have been obtained at optimized parameters. The ablation depth is also enhanced greatly by pocket scanning to increase almost linearly with the laser fluence and scanning loop. There are no limitations of saturation as that observed in the cases of direct scanning.