[15a-B10-1~13] 13.4 Si wafer processing /Si based thin film /MEMS/Integration technology

▲ [15a-B10-13] High Mechanical Strength in Gold Films Electroplated with Supercritical Carbon Dioxide for MEMS Applications

〇(D)Haochun Tang¹, Chun-Yi Chen^1,2, Tso-Fu Mark Chang^1,2, Daisuke Yamane^1,2, Katsuyuki Machida^1,2,3, Kazuya Masu^1,2, Masato Sone^1,2 (1.IIR Tokyo Tech, 2.CREST JST, 3.NTT AT Corp.)

Keywords:Gold, Electroplating, Supercritical carbon dioxide

Recently, electroplated gold films have attracted much attention because of their desirable properties for micro-electrical-mechanical systems (MEMS) devices. However, it is known that mechanical strength of gold materials is relatively low when compared with the other metallic materials, which is always a concern in practical MEMS applications especially for the movable components. On the other hand, an alternative electroplating (EP) method employing supercritical carbon dioxide (scCO₂) in film deposition was proposed to be effective on the grain refinement as demonstrated in electroplating of Ni and Cu. Based on the Hall-Petch relationship, finer grain would result in strengthening of the metallic materials. It is expected that the mechanical strength of electroplated gold could be enhanced by employing scCO₂ in the EP process.