Ultrafast laser patterning of OLEDs for solid-state lighting

Traditionally, laser micromachining has relied on Q-switched Diode-Pumped Solid State (DPSS), excimer and CO2 lasers of typically nanosecond (ns) pulse duration or longer. These lasers offer relatively high average power and can achieve high volume removal rates
harnessing a combined etching effect from laser and laser-induced plasma processes [1]. As a result, micro-drilling,scribing and fine cutting applications have benefited on an industrial scale [2]. However, the driving mechanism even at short wavelengths is strongly thermal in nature. This arises largely as a result of secondary plasma heating of the target and substrate thermal conduction, and it limits fine control of the ablation process. Undesirable side effects near the irradiated regions such as micro-cracking or edge chipping, burr formation and particle debris that often accompany
the micromachining process confirm this claim. As a result, successful laser machining with ns lasers is still viewed by many as a ‘black art’. However, with the ever-increasing
miniaturisation of products and processes, this picture is changing rapidly.