Etching blazed grating into quartz substrate with selectivity 1:1 against photoresist by inductively coupled plasma technology

Inductively coupled plasma (ICP) etching technology is becoming widely used in the fabrication of micro-optical elements. Because of its advantages such as relatively high etching rate and anisotropic etching, ICP technology is receiving more attention. Selectivity 1:1 of the substrate against photoresist is very convenient, because we can easily get the same structures which were designed on the photoresist. Through extensive experiments we have achieved an optimized etching condition under which the transfer process generates fairly smooth etched structures with selectivity 1:1. The first order diffraction efficiency of the etched blazed gratings is 83.5% which is a little bit lower than the theoretical efficiency 88.9%. The diffraction of etched blazed gratings matches the theoretical results well.