High-Strength Electroplated Au–Cu Alloys as Micro-Components in MEMS Devices. Issue 4 (24th February 2017)

• Record Type: Journal Article
• Authors: Tang, Haochun; Chen, Chun-Yi; Yoshiba, Masaharu; Nagoshi, Takashi; Chang, Tso-Fu Mark; Yamane, Daisuke; Machida, Katsuyuki; Masu, Kazuya; Sone, Masato
• Is Part Of: Journal of the Electrochemical Society. Volume 164:Issue 4(2017)
• Page Start: D244
• Page End: D247
• Publication Date: 2017-02-24
• Subjects: Au-Cu alloy -- compression test -- electroplating -- micro-mechanical property; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.141704jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Au–Cu alloy electroplating is a promising method for fabrication of micro-components used in MEMS devices. Micro-mechanical properties of Au–Cu alloy films fabricated by galvanostatic electroplating are reported in this study. Influences of the current density on surface morphology, crystalline structure, Cu content, and micro-mechanical properties were investigated. An optimum current density at 6 mA/cm 2 was attained for the effects of surface smoothening and grain refinement as the current density was applied in the range of 2–9 mA/cm 2 . Micro-pillars having dimensions of 10 × 10 × 20 μm 3 were fabricated from the electroplated Au–Cu alloy films by focus ion beam and used in the uniaxial micro-compression tests. The highest yield stress of 1.15 GPa was achieved from the film electroplated at 6 mA/cm 2, which the grain size was about 5.3 nm with Cu content of 12.3 wt%. The high yield stress was a synergistic effect of the grain boundary strengthening mechanism with the solid solution strengthening mechanism.