Water Jet Guided Laser Cutting of Silicon Thin Films Using 515nm Disk Laser

We report on a comprehensive study of water jet guided laser cutting of polycrystalline silicon thin films using a pulsed 515nm disk laser. The optimization of the cutting process of polycrystalline silicon wafers having a thickness of 200-300 mu m is based on a Design of Experiments (DOE) approach taking into account process parameters such as laser power, cutting speed, laser repetition rate, water pressure and nozzle diameter, respectively. The targeted response of the DOE is defined by both the quality as well as the productivity of the cutting process. While the former is measured by the mechanical strength and the chipping of the wafers, the latter is determined by the ablation depth and the cutting kerf cross-sectional area. Our analysis identifies the most influencing parameters on the cutting process, provides insight into the interactions of these parameters and, finally, delivers an optimized process parameter window for water jet guided laser cutting of thin silicon films. DOI: 10.2961/jlmn.2011.02.0013