Etching of silicon dioxide in off-electrode plasma using a chrome mask

We discuss results of etching a Cr-SiO$_2$ structure is in a flow of off-electrode gas-discharge plasma in a CF$_4$ + O$_2$ gas at a ratio of 50: 1, at the discharge current I = 80 mA, accelerating voltage U = 1.2 kV, and process duration t = 5 min. It was shown that changes in the intensity of Raman spectral bands in the course of etching correspond to nanoscale changes in the thin Cr-SiO$_2$ films and a chrome mask. The peculiarity of the etching process consists in the removal of the Cr$_2$O$_3$ oxide with increasing amount of nitrogen molecules in the structure of the Cr film. It was found that spray products deposited inside the chrome mask windows at U = 1.2 kV and I = 80 mA are in the form of Cr$_2$N, according to their Raman spectra.