Scaling percussion drilling processes by ultrashort laser pulses using advanced beam shaping

Drilling processes by ultrashort laser pulses meet the demand for high-end applications in the display and electronics industry. Especially the manufacturing of microstructures requires highest accuracy and minimal damage of the workpiece. A variety of applications, like the production of blind holes in multi-layer stacks or through holes in metal foils demand specific processing constraints. For example, applications like fine metal mask (FMM) require exact rectangular hole shape as well as tailored taper angles and minimized residual particle contamination. In large scale production environments, the total throughput also becomes decisive. To achieve these challenging needs, the spatial and temporal energy deposition are crucial parameters. In this context, beam shaping offers unique potential for controlling and scaling these micromachining processes. To pursue this approach, we present a novel adaptive beam shaping setup combined with a flexible TRUMPF TruMicro femtosecond laser. Our investigations target percussion drilling applications with various intensity distributions. We discuss methods for process optimization by controlling the spatial and temporal energy deposition. This enables us to analyze the correlation between micromachining results and the tailored absorption. Our investigations aim on shaping several beam properties like phase, amplitude, polarization and propagation characteristics using a liquid-crystal-on-silicon-spatial-light-modulator (LCOS-SLM). By correcting aberrations with a closed-loop setup, we generate robust process specific top-hat like intensity distributions.