High-repetition-rate excimer laser for micromachining

Abstract

Excimer lasers are nowadays well established UV laser sources for the wide area of micromachining. Their high energy and average power at short UV wavelengths makes them ideal for ablation of various materials e. g. polyamide and PMMA. The typical excimer laser sources used in micro machining deliver several hundred mJ of energy at repetition rates of up to 400 Hz. In parallel to this high-energy-micromachining an alternative excimer based method came up during the last years. This new technology is driven by the ever shrinking feature sizes of microelectronic circuits and utilises UV wavelength resist exposure. The resist exposure technology offers new possibilities also for micromachining. It is ideal for micro applications which require high precision patterning - with a positional accuracy of below 50 microns - at high volume throughput. In this process the laser energy dose may be built up in several shots, UV lasers with several hundred mJ cannot be utilised. Hence, high repetition rate lasers are needed. In this paper the basic feature and performance characteristics of the new laser will be presented.