Electrodeposition of Organic Dielectric Film and Its Application to Vibrational Microelectromechanical System Devices

Abstract

In this paper, we describe the application of electrodeposition to microelectromechanical system (MEMS) devices made of gold. After the release ashing of an organic sacrificial layer by oxygen plasma exposure, the thickness of the organic dielectric film electrodeposited on gold surfaces was found to be nonuniform. A surface analysis by X-ray photoelectron spectroscopy revealed that the causes of the nonuniformity were the differences in chemical states and amounts of gold oxide that arose from oxygen plasma exposure at different places. A uniform coating was obtained by removing the gold oxide by hydrochloric acid dipping before electrodeposition on gold comb-shaped electrodes in a vibrational MEMS device. This uniform coating prevents electrical shorts and in-use sticking between the gold vibrator and electrode in the device, ensuring high durability.