Since the beginning of the microelectronics era ongoing miniaturization of transistors has been accompanied by the development of ever more intricate interconnects. Presently these range from nanoscale on-chip wiring to 3D TSV for chip stacking along with related structures for advanced packaging and printed circuit board applications. Electrodeposition has been a key process in the void-free fabrication of recessed patterned Cu interconnects by virtue of surfactant-mediated superconformal film growth. This lecture will detail how the combination of electroanalytical kinetics, metallurgical analysis, and in situ electrochemical surface science measurements can be used to reveal the mechanisms associated with this unusual deposition mode. The generality of the findings to the deposition of other metals and applications will also be detailed.
Thomas P Moffat is with the Functional Nanostructured Materials group in the Material Measurement Laboratory at NIST. He began his research career as an undergraduate student working part time in the laboratory of Barry Lichter and William Flanagan at Vanderbilt University. After receiving his B.E. in 1982 and M.Sc. in 1984, he joined Ron Latanision’s group in the H.H. Uhlig Laboratory at MIT. In 1989, he received a Sc.D. degree for his work exploring the chemical passivity of chromium-based metallic glasses. This was followed by a two year stint as a postdoctoral associate in Allen Bard’s chemistry laboratory at the University of Texas, Austin studying the corrosion and passivation of metals using scanning tunneling microscopy. Since joining NIST in 1991, Dr. Moffat’s efforts have focused on using electroanalytical and surface science methods to understand the structure, composition, and electrochemical performance of thin films. Exploration into surfactant mediated electrochemical deposition of microelectronic interconnects and, more recently, electrocatalysts have been of particular interest. For his work on superconformal electrodeposition, he received the NIST Excellence in Technology Transfer Award (2023), NIST’s Samuel Wesley Stratton Award (2011), named after the first director of the Institute, the Research Award of the ECS Electrodeposition Division (2006) and the Gold Medal award of the United States Department of Commerce (2001). To date he has authored or co-authored more than 200 technical papers. He was elected a Fellow of the Electrochemical Society in 2009. Dr. Moffat is also an active member of the Electrochemical Society, International Society of Electrochemistry, Materials Research Society and AAAS.