Overlay error effects on polycarbonate structures produced by 248 nm UV laser ablation tool

The overlay and stitching error effects in the boundary area between the adjacent ablated volumes of the polycarbonate (PC) substrate under 248 nm KrF excimer pulsed radiation have been studied. We have investigated the effects of different overlay errors on the surface roughness, and categorized these to five different cases. The effect of increasing the number of laser shots (25 to 500) has been examined with a fluence of 1.1 J/cm2. The results of our analysis using Scanning Electron Microscopy (SEM), Laser Scanning Confocal Microscopy (LSCM) and optical microscopy are presented. We find that by applying the different strategies we can successfully reduce the error by 80 %. This paper also presents the strategies and a software system to control these micromachining parameters.