Historical Perspectives on Evolution from Elctrodeposition to Electrochemistry

Abstract

Among numerous findings by human beings, electrodeposition is of great importance in the whole invention and is getting to be a core technology to date. The applications of electroplating used in electronics devices, magnetic recording heads and media, chemical biosensors, and batteries are some typical examples surrounding our present world. Looking back on the history of electrodeposition, the first trial was carried out in the Mesopotamian-era in 1500 BC, which was a Sn plating on iron wares. For Japan, the beginning of plating was performed back in the 6th century for a Au amalgam plating on the Buddha statue at Asuka-era Temple. Hence, the technology of electrodeposition has been developed and evolved for a long period of time along with humankind. While electrodeposition is known to be a traditional way to form metal or non-metal ions on various substrates, it is still kept being one of the cutting edge technologies to date. Because desired thin films, such as CoFeNi for hard disk and Cu wiring for silicon devices, can be easily obtained by the fine control of the chemistry on the interface between the electrode and electrolyte. The sequential high-throughput with outstanding cost effectiveness also push forward this technology to practical applications in various industrial fields. An example of the fine control of deposited films popped up in our mind is the idea of UPD (underpotential deposition) by ad-atom in 1978. Such an idea of ppm or ppt content of metal ions in the plating bath resulted in the practical realization of electroless plating disk for PATTY HDD device (1981 NEC,NTT). Electrodeposition is also known to be a game-changer in the scientific history as well. For the fabrication of soft magnetic materials, the electrodeposited thin film of Co65Ni23Ni12 achieved low-Hc with high-Bs for the first time, which was breaking the common sense that high-Bs is incompatible with low-Hc in soft magnetic materials. [1, 2] Such an electroplating technology is on going to the next stage for 3D memories. Ever since electrodeposition was conducted in earnest by Jacobi et al in 1837, its practical use in sub-micron scale was established in 1997 as damascene process to ULSI internal wiring technology and is now available to handle atomic-scale of fabrication in various fields. This year marks the 100th anniversary of the establishment of the ECS Electrodeposition Division. There is no doubt that ECS has contributed significantly to the development of the Electrodeposition field since 1922. In today's lecture, we will introduce our research concept on electrodeposition in the various fields based on electrochemistry, such as magnetism, sensors, and electronics on the basis of our achievements of their practical use for future industrial usage including battery devices. [3] [1] T. Osaka et al., “A soft magnetic CoNiFe film with high saturation magnetic flux density and low coercivity”, Nature, 392, 796 (1998). [2] T. Osaka et al., “Influence of crystalline structure and sulfur inclusion on corrosion properties of electrodeposited CoNiFe soft magnetic films”, Journal of the Electrochemical Society, 146, 2092 (1999). [3] T. Osaka, “Spotlight on Japanese Battery Technologies”, Nature jobs, 2015. Figure 1