Meet the editors

Prof. Masato Sone completed his doctor degree in engineering at the age of 28 at Tokyo Institute of Technology. He worked as a researcher in the Nippon Oil Company from 1996 to 2000. He was an assistant professor and then a research associate professor at Tokyo University of Agriculture and Technology from 2000 to 2005. He attained his current position of associate professor and full professor at Tokyo Institute of Technology in 2005. He has

published more than 170 papers in scientific journals. His interests are microelectronics, metallurgy, surface finishing, chemical engineering, and liquid crystal and polymer science. His recent topic of interest is material design and the evaluation of electroplated gold alloys for high-sensitivity CMOS-MEMS accelerometers.

Prof. Kazuya Masu received his BE, ME, and PhD degrees in Electronics Engineering from Tokyo Institute of Technology (Tokyo Tech). He was an assistant professor and an associate professor at Tohoku University from 1982. In 2000, he was a professor and Director-General of the Institute of Innovative Research, Tokyo Tech, until March 2018. He was a visiting professor at the Georgia Institute of Technology in 2002 and 2005.

He is currently President of Tokyo Tech. He has published more than 225 papers in scientific journals. He received an IEICE Electronics Society Award in 2004, IEICE Achievement Award in 2013, and IEEJ Outstanding Achievement Award in 2014. He served as Vice President of JSAP in 2014–2015. He is a JSAP Fellow, IEEJ Fellow, and IEICE Fellow.

**Preface III**

Evaluation Method of Electrodeposited Metal **1**

**Chapter 1 3**

Electrodeposition of Pure Noble Metal **19**

**Chapter 2 21**

**Chapter 3 39**

**Chapter 4 55**

Alloy and Composite of Electrodeposited Noble Metal **69**

**Chapter 5 71**

**Chapter 6 93**

Hard Pure-Gold and Gold-CNT Composite Plating Using Electrodeposition

Cu Wiring Fabrication by Supercritical Fluid Deposition for MEMS Devices

*by Chun-Yi Chen, Masaharu Yoshiba, Haochun Tang, Tso-Fu Mark Chang, Takashi Nagoshi, Daisuke Yamane, Toshifumi Konishi and Katsuyuki Machida*

Electrodeposition of Gold Alloys and the Mechanical Properties *by Haochun Tang, Tso-Fu Mark Chang, Chun-Yi Chen, Takashi Nagoshi,* 

*Daisuke Yamane, Toshifumi Konishi and Katsuyuki Machida*

Technique with Environmentally Friendly Sulfite Bath

*by Masatsugu Fujishige and Susumu Arai*

Evaluation Methods of Mechanical Properties of Micro-Sized Specimens

Morphology Controlled Synthesis of the Nanostructured Gold

*by Takashi Nagoshi, Tso-Fu Mark Chang*

by Electrodeposition Techniques

*by Brij Mohan Mundotiya and Wahdat Ullah*

Pulse-Current Electrodeposition of Gold

**Section 1**

Contents

**Section 2**

*by Eiichi Kondoh*

**Section 3**

## Contents


## **Chapter 7 111**

Electrodeposition of High-Functional Metal Oxide on Noble Metal for MEMS Devices *by Wan-Ting Chiu, Chun-Yi Chen, Tso-Fu Mark Chang, Tomoko Hashimoto and Hiromichi Kurosu*

## **Chapter 8 133**

Multi-Physics Simulation Platform and Multi-Layer Metal Technology for CMOS-MEMS Accelerometer with Gold Proof Mass *by Katsuyuki Machida,Toshifumi Konishi, Daisuke Yamane, Hiroshi Toshiyoshi and Hiroyuki Ito*

Preface

The history of metallic materials is thought to have begun about 11,000 years ago because of their brilliant beautiful features. The noble metals, especially gold, are often used as components in electronic devices because of their high electrical conductivity, chemical stability, corrosion resistance, and high density.

In the field of microelectromechanical system (MEMS) devices, continuous miniaturization, while maintaining high sensitivity, is always a challenge. Especially for MEMS accelerometers, sensitivity is highly affected by Brownian noise, and structures with sufficient mass in the device are needed to suppress this noise. Because of the requirement of overall mass of the components, it is difficult to reduce the dimensions of components to allow further miniaturization of the MEMS device.

This book presents recent progress in noble metal electrodeposition and the application of gold materials in the realization of highly sensitive complementary metal-oxide semiconductor-microelectromechanical systems (CMOS-MEMS) accelerometers. A feature of the CMOS-MEMS accelerometer is the use of gold proofmass. The high density of gold enables sensitivity enhancement by reducing thermomechanical noise, which is inversely proportional to overall mass of the proofmass. The developed CMOS-MEMS multiphysics design environment is also presented. An equivalent circuit of a MEMS accelerometer has been designed to simultaneously clarify both mechanical and electrical behaviors. One of the potential applications of the highly sensitive accelerometer is also discussed by focusing

> **Dr. Masato Sone and Dr. Kazuya Masu** Tokyo Institute of Technology, Japan

on early-stage diagnosis of Parkinson's disease.
