Thermochemical laser writing of silicide masks on dual-layer films a-Si/Cr

Abstract

The paper presents experimental results on the development of thermochemical laser technology for writing on a dual-layer a-Si/Cr film. This technology shows the possibility of manufacturing a transmitting photomask by removing the unexposed a-Si surface layer in the first selective etchant and subsequently etching the chromium layer below it in the second selective etchant. The areas of the chromium film covered with a silicide mask remain untouched during these operations. It has been shown that using a silicon cover antireflection coating (at a wavelength of 405 nm) can significantly increase the resolution of thermochemical laser writing technology. Moreover, the investigation reveals an expansion of the power range of effective laser writing during thermochemical modification of an a-Si/Cr film compared to laser writing on a Cr film, enabling smoother control of the duty cycle of the formed structures.