Efficient Micromachining of Thin Films with Nanosecond Lasers

Abstract

AbstractEspecially for micromachining, single‐mode solid state lasers are well established nowadays. Due to their ultra short pulse duration and low pulse energies picosecond and especially femtosecond lasers show a quite high precision in micromachining processes and avoid thermal effects. However, these advantages in process quality require higher investment costs for the lasers. As a consequence, in cost sensitive markets such ultra short pulse systems are only rarely used. Hence, the series production of, e.g., solar panels is still mainly based on nanosecond lasers, as these systems are available at significantly lower costs. Besides pulse duration also the wavelength and the beam profile have a strong influence on the quality of the laser ablation process. For many applications the raw Gaussian beam profile does not lead to the best result. Therefore, an adaption of the beam profile to the process is highly desired. It has been shown that especially beam profiles with a homogeneous intensity distribution, so called Top‐Hat profiles can improve the quality of an ablation process and lead to a reduction of the processing costs. This applies in particular to thin film processing. This article shows how a cost efficient micromachining process of thin film layers can be realized by using nanosecond lasers in combination with various beam shaping optics.