A Multi-Scale Model for Ultra Short Pulsed Parallel Laser Structuring — Part I. the Micro-Scale Model

In the field of consumer electronics, especially in display manufacturing, Full Metal Masks (FMMs) with ever increasing structural requirements are needed. In addition, manufacturing technologies should meet these requirements at high productivity. High power ultra short pulsed lasers in combination with a multi-beam scanner are a key enabler by combining the high precision of laser manufacturing tools with the productivity of parallel processing. In order to produce FMMs in the required quality, temperature-related distortions due to heat accumulation must be avoided. Therefore, a deep understanding of the process is essential. In this treatise, the ablation of a single hole by multiple laser pulses is modeled by three submodels: 1. a fluence threshold model, 2. a level-set method, and 3. a heat conduction problem. The simulation results are compared with experiments and show good agreement. A comprehensive simulation of a complete foil resolving each laser pulse is, however, not feasible because of the computational demands. In future research, a multi-scale model is developed which retains most of the accuracy while tremendously speeding up the computation to enable the simulation of the whole process.