RIE patterning technology of Zr-based metallic glass for MEMS devices fabrication

In this work, metallic glass films (Zr-Cu-Al-Ni) were successfully deposited and patterned by sputter and reactive ion etching (RIE) technologies for widening micro electro mechanical system (MEMS) field. The amorphous structure of the deposited Zr-based alloy films were confirmed by X-ray Diffraction (XRD) and transmission electron microscopy (TEM). The home-made RIE equipment was used to dry etch the metallic glass films for patterning. This technique removes the atoms by ion bombardment. The different gases were selected during the RIE plasma etching process such as argon (Ar), octafluorocyclobutane (C₄F₈) and sulphur hexafluoride (SF₆). Two kind photoresists, AZP4620 and OFPR800, were used as the etching masks for transferring the patterns to Zr-based metallic glass thin film. The etching rate and etching selectivity of photoresist and metallic glass were tested in different photoresist hard-baking conditions and different etching RF power. Besides, the condition of employing different working gases during RIE etching process was carried out and studied in this work. As a result, the metallic glass Zr-Cu-Al-Ni films were successfully structured with 20nm/min etching rate and 1:3.2 (metallic glass: photoresist) etching selectivity by using a mixture of Ar and C₄F₈ gases. This plasma etching technology realizes metallic glass films patterning for advanced MEMS devices fabrication.