Divalent ion mixed effect of calcium aluminosilicate glasses (CAS) on thermal properties and fluorocarbon plasma resistance

•Divalent ion oxides (RO, R: Mg, Sr, Ba, Zn) were added in CaO-Al2O3-SiO2 glasses.•MgO and ZnO reduced glass transition temperatures and thermal expansion.•Etching rates with CF4/O2/Ar plasma gas were increased by mixing divalent ion oxides. When divalent oxides (RO, R: Mg, Sr, Ba, Zn) are mixed in two CaO-Al2O3-SiO2 glasses, thermal expansion, glass transition temperature and corrosion (or etching) rate of CF4/O2/Ar mixed gas were confirmed. The decreases in the thermal expansion coefficient and glass transition temperature were most effective when MgO and ZnO were mixed. As a result of high-density plasma dry etching, all glasses were improved compared to quartz glass, alumina, and sapphire even though the etching rate increased when divalent oxide was mixed. Regardless of the glass composition, the plasma resistance was thought to be closely related to the boiling point of the mixed divalent fluoride. In particular, the surface microstructure after the etching of the glass maintained the original mirror surface, unlike quartz glass.