Etching quartz with inductively coupled plasma etching equipment

Inductively Coupled Plasma (ICP) can achieve high density plasma in low pressure, so it has a number of significant advantages such as improved etching rates, better profile control, improved uniformity, greatly increased selectivity and a dramatic reduction in radiation damage and contamination. In optics, quartz is an ideal optical material with transmitting spectral range from deep ultraviolet to far infrared. So we systematically studied the etching characteristics of quartz by using a Inductively Coupled Plasma (ICP) etching system. In the experiments, the gas was the mixture of CHF3, O-2 and Ar, and the chamber pressure was about 10 mTorr. The influences of gas flow rate and the power of the radio frequency on etching rate were optimized. The uniformity and repeatability of the etching technology were also studied. After residue mask material was removed by wet chemical solution, no polymer was observed on the surfaces of samples, and the surfaces of the fabricated quartz elements were smooth and clean. The optimized etching process is important for the fabrication of micro-optical elements based on quartz. Using this etching process, many gratings such as Dammann grating, rectangular groove grating, and optical disk grating can be fabricated successfully.