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Crack-free micromachining on glass using an economic Q-switched 532 nm laser

Laser-induced backside wet etching (LIBWE) is an effective method for crack-free etching of transparent materials such as glass and quartz. Traditionally, LIBWE is performed using ultraviolet (UV) laser sources. However, this study describes the use of an economic Q-switched 532 nm green laser in the LIBWE microfabrication of sodalime glass substrates. Using a common organic dye (Rose Bengal) as the photoetchant, crack-free microstructures with a minimum feature size of 18 µm are obtained. The typical etch rate is approximately 10 to 70 nm/pulse and the maximum attainable depth is found to be approximately 65 µm. The etch threshold is 5.7 J cm−2. The surface quality of the micro-trenches produced by the visible LIBWE source is comparable to that obtained in the traditional UV LIBWE process. Microtrenching in sodalime is demonstrated to show the feasibility of microfluidic chip development using visible LIBWE.