High-precision ultrashort pulsed laser processing of metal foils using an advanced multibeam optic

Abstract

In the field of micro- and nanostructuring multibeam ultrashort pulsed laser processing attracts increasing attention due to its ability to generate periodic pattern like filters with a processing speed of up to 22.000 holes/sec. The multibeamscanner (MBS) developed at the Fraunhofer Institute for Laser Technology ILT enables laser processing with > 200 beams in parallel and a precision of < 1 μm. The MBS combines the latest femtosecond laser technology with a sophisticated optical concept. High precision multibeam processing is a useful approach to increase the productivity in laser material processing by means of ultrashort pulsed (USP) laser radiation. The developed multibeamscanner is capable of drilling holes with extremely small outlet diameters (< 1μm) into various materials with a customized arrangement and a density of more than 10.000 holes per mm². These holes can also be shaped according to customer requirements. Thus, this technology has become relevant for applications in the fields of consumer electronics, filtration, pharma and biotech industry. In addition to the various applications in terms of microfilter fabrication, the aim of this paper is to show the versatile use for structuring any 2.5 dimensional geometry on flat workpieces and to demonstrate the current and future possibilities of a multiscale simulation. To predict the ablation shape, temperature distribution and distortion in a multibeam processing, a detailed simulation of the physical processes during and after the laser ablation is required. A multiscale model to simulate the processing of larger workpieces is developed involving the interaction of multiple beams. Thereby, an increase in productivity by maintaining high process quality can be possible by a strongly parallelized USP laser process 1.