Enhancing the Plasma-Resistance Properties of Li 2 O–Al 2 O 3 –SiO 2 Glasses for the Semiconductor Etch Process via Alkaline Earth Oxide Incorporation.

To develop plasma-resistant glass materials suitable for semiconductor etching processes, we introduced alkaline earth oxides (ROs) into a Li₂O–Al₂O₃–SiO₂ (LAS) glass. Analysis of glass properties with respect to the additives revealed that among the analyzed materials, the LAS material in which Li₂O was partially replaced by MgO (MLAS) exhibited the most favorable characteristics, including a low dielectric constant (6.3) and thermal expansion coefficient (2.302 × 10⁻⁶/°C). The high performance of MLAS is attributed to the high ionic field strength of Mg²⁺ ions, which restricts the movement of Li⁺ ions under the influence of electric fields and thermal vibrations at elevated temperatures. When exposed to CF₄/O₂/Ar plasma, the etching speed of RO-doped glasses decreased compared with that of quartz and LAS glass, primarily owing to the generation of a high-sublimation-point fluoride layer on the surface. Herein, MLAS demonstrated the slowest etching speed, indicating exceptional plasma resistance. X-ray photoelectron spectroscopy analysis conducted immediately after plasma etching revealed that the oxidation-to-fluorination ratio of Li was the lowest for MLAS. This observation suggests that the presence of Mg²⁺ ions in the plasma discharge inhibits the migration of Li⁺ ions toward the surface, thereby contributing to the excellent plasma resistance of MLAS. [ABSTRACT FROM AUTHOR]