Cumulative damage effects in different machining strategies for 2.5D laser micro structuring of polyimide

Polymers play an important role in many applications such as microelectronics and medical devices. Micro-channels and shaped holes can be produced by 2.5D micro-structuring with excimer laser sources using mask projection. The industrial cost associated with these processes can be greatly reduced by the use of solid-state lasers due to their lower cost and maintenance. For this purpose, we investigate the interaction of polyimide (Kapton™) with solid-state lasers emitting in the UV (266 & 355 nm) spectral range. The study presents a comparison of the ablation profiles obtained for different laser sources and these are discussed in term of roughness and efficiency. Limitations on the actual motion system (scan-head) are evident and the need to control the material removed by a small Gaussian beam in terms of overlapping for the direct writing process will be highlighted.