FEM based 3D simulation of nanosecond UV laser ablation

The aim of our research is to provide a simulation tool for manufacturing processes that takes the influence of temperature distribution. Laser inducted heat and the ablation of any kind of material is the key for precise material micro processing. All the laser parameters like power, wavelength and pulse repetition frequency are taken into account. To establish such simulation software, a finite element model was set up which is able to describe the thermal processes and ablation induced by laser irradiation of materials (FR4, copper). The etch rate description usually applied for excimer lasers was slightly altered to be adequate for Gaussian lasers by calculating with pulse energy instead of fluence. This theoretical consideration was proved by experiments. The experiments also revealed the temperature dependence of etch rate and the influence of pulse repetition frequency on the amount of ablated material. The experimental, analytical and simulation results are in good agreement.