Underwater Excimer Laser Micromachining of Silicon and Metals
Y-H. Long, Y-J Xie, L-C. Xiong and T-L. Shi
To investigate the technique of laser etching under different mediums, micromachining of silicon and metals were carried out by using a pulsed KrF excimer laser that generates laser energy in the range of 150 to 250 mJ. Laser etching experiments were conducted on samples both in air and under water. Based on the results of experiments, basic etching appearances and etching velocities by excimer laser etching silicon under the two mediums were researched, and the etching appearances of several metals in two mediums were contrastively analysed. As a result, the molten material is easy to be removed in water-assisted micromachining, which helps to improve the processed surface quality; the restriction of water improves the impact effect which leads to increase the etching velocity of silicon, but it is easy to produce micro-cracks in the brittle material. Laser etching metal underwater is helpful to improve the surface quality, but the etching rate decreased.
Keywords: Excimer laser, underwater, water-assisted micromachining, ablation, etching, silicon, metal