Highly Anisotropic Fluorine?Based Plasma Etching of Ultralow Expansion Glass

Deep etching of glass and ceramics is far more challenging than silicon etching. For thermally insensitive microelectromechanical microoptical systems, zero-expansion materials such as Zerodur or ultralow expansion (ULE) are intriguing. In contrast to that exhibits a complex network composition, ULE consists only two components, namely, TiO2 SiO2. This fact highly beneficial for plasma Herein, deep fluorine-based process 7972 shown the first time yields an etch rate up 425 nm min?1 while still achieving vertical sidewall angles 87°. The offers selectivity almost 20 with respect nickel hard mask overall comparable fused silica. chemical surface composition additionally investigated elucidate impact tool configuration in comparison previously published results achieved Zerodur. Therefore, narrow trenches can be etched high anisotropy, which supports prospective implementation microstructures, instance, metrology miniaturized precision applications.