Historical Perspectives on Electroplating during the Past 100 Years

The development of electrodeposition practice and the underlying science and engineering methods that emerged during the past century will be traced. Beginning in the late 19 th century, many large-scale electrolytic technologies became feasible owing to the invention of the electric generator. These included electrowinning, electrorefining, and electrodeposition, among others. Their early development and commercial use took place before the recognition of many fundamental scientific and engineering principles. As a result, these industries came to be characterized by slow evolutionary change based on past experience and intuitive insight. In 1913, a symposium on electrodeposition was arguably the first to apply systematic academic effort to the art of the plater, and thus promote cooperation between science and technology. The success of these activities led, in 1922, to formation of the Electrodeposition Division. For several subsequent decades, the growth of electrodeposition technology took place while electrochemists developed experimental tools (e.g. polarography), data (e.g., thermodynamic) and theories (e.g. non-ideal electrolytic solutions). By the 1950s there were an enormous number of electrodeposition applications, but the sense was emerging that progress based on empirical experimentation was rapidly coming to a close, and that further significant advances could be made only when the fundamentals of the plating processes are more completely understood. During the 1960s, the invention of new materials revolutionized the electrodeposition industries. In addition, the digital computer came into use for obtaining the current distribution in simple geometries. In addition, refined experimental research methods were developed, iincluding the potentiostatic power supply, rotating disk, “model” experimental systems, and various electroanalytical and surface-science techniques, In the 1970s, the field of electrodeposition technology saw significant new demands arising from changed availability of energy, feedstock, and capital as well as increased attention to waste treatment. These events shattered the empirical traditions of the past, and triggered new interest in ‘modern’ electrodeposition science and engineering built o a foundation of thermodynamics, kinetics, transport phenomena, and current distribution aspects. In the 1980s, the magnetic thin-film storage head, energized the entire microelectronics field of electrodeposition technology. Also, studies with single crystal electrodes and with surface scanning microscopies provided spectacular new capabilities for investigations at time scales, molecular specificity, and spatial resolution that were orders of magnitude superior to those of only a decade earlier. By the 1990s, important advances were made in understanding phenomena associated with defects, additives, solvent effects, nanoscale phenomena, surface films, mechanisms of lattice formation, among others. In addition, mathematical modeling of electrodeposition systems moved down-scale to include both continuum and non-continuum phenomena. During the 2000s, the shift from aluminum to electrodeposited copper for on-chip interconnections represented one of the most important change in materials since the beginning of the semiconductor industry. In the 2010s, the mathematical tools used to explore electrochemical systems expanded beyond the traditional continuum methods to include kinetic Monte Carlo, molecular dynamics, and quantum chemistry. In conclusion, throughout the history of electrodeposition science and technology, several high-level trends may be recognized: Advances often came from outside the electrodeposition field. It is important to read the literature widely, and with enough informed judgment to recognize analogies between seemingly different situations; Many electrodeposition systems have been improved over the course of many years. The literature contains a gold mine of applications worth further study. It is important to recognize when new science or engineering materials and methods can provide fresh insights to improving old, but very important, applications; Over the past century, there have been periods when significant gaps existed between scientific understanding of electrochemical phenomena, and our ability to incorporate it into engineering practice. It is important to identify problems worth solving and to release impedements to introduction of new ideas. Today, the ability to use numerical simulations to achieve precise quantitative understanding at new levels of magnitude, sophistication, and completeness offers a significant challenge. It is therefore important to develop re-usable electrochemical engineering methods, and to align tight integration of discovery science, application design, research prototyping and manufacturing collaboration.