Synchrotron radiation-assisted etching of Si in the presence of reactive species produced by microwave discharge

Abstract

The photochemical etching of Si has been studied using synchrotron radiation (SR) in the presence of reactive species produced by 2.45 GHz microwave discharge in a mixture of SF6 and Ar. The effect of SR irradiation was investigated, and it was found that the SR-irradiated region was etched at a rate one order of magnitude faster than was the nonirradiated region. A clear fringe pattern appeared parallel to the edge of the replicated mask pattern on the Si surface. These fringes were interpreted as caused by the diffraction effect of the incident beam at the mask. By comparing the etched fringe pattern with the calculated one of the Fresnel diffraction, it was clarified that the etched pattern agreed with the diffraction one. That is, the spatial distribution of the photointensity was replicated on the etched surface. Therefore, it was concluded that the main effect of SR irradiation was to activate the etching reaction on the sample surface.