High-purity SiO2 via H2O-assisted FEBID: a game-changer for DUV lithography

Focused electron beam-induced deposition (FEBID) of pure SiO2 has been successfully demonstrated on a 150-nm-thick Al layer evaporated on Silicon wafers. The process uses a tetramethylsilane precursor, and the addition of sufficient amounts of water vapor is critical to achieving pure SiO2 deposition. The resulting deposits exhibit nearly 100% transmission at a 193-nm wavelength, making them suitable for Deep Ultraviolet Light optical applications. The H2O vapor-assisted FEBID process involves the simultaneous deposition of pure SiO2 and the etching of contaminants. In addition, the study explores the influence of varying dwell times on the deposition dynamics and the required water vapor flow for achieving pure SiO2, leading to high-quality materials for advanced optical applications.