Analysis of plasma etching reactivity of bismuth aluminosilicate glasses using fluorine concentration

Abstract

Al2O3 was replaced with AlF3 in the composition of bismuth aluminosilicate glasses, and the resistance of the resulting glasses to CF4/Ar/O2 plasma was tested. The results were interpreted from the standpoint of glass structure. The resistance to plasma etching increased as the F concentration in the glass increased. After etching, all samples retained a smooth surface structure, and no craters or reactive structures were detected in the microstructure. The formation of Al-F bonds in the glass was confirmed by nuclear magnetic resonance spectroscopy. The increase in plasma resistance at higher F concentrations suggests that the fluorine bonds in the glass structure are involved in decreasing the etching rate. This is possibly due to the higher sublimation temperature of AlFx, which retards the fluorocarbon plasma reaction.