Synchrotron radiation (SR) excited etching of SiC film was studied using a mixture of SF6 and Ar. It was found that only the region irradiated by SR was etched. By introducing a 2.45 GHz microwave discharge as a generator of reactive species, the etch rate of the irradiated region was increased by one order of magnitude while retaining the area selectivity. It was deter-mined that the etching reaction occurred due to a sur-face photochemical reaction and was promoted by the increase in the number of reactive species affected by means of microwave discharge. From the dependence of the etch rate on the photon energy using monochromatic soft x rays, it was found that the photoabsorption of the sample took part in the etching reaction.