Electrodeposited Nanocrystalline Copper for Printed Wiring Board Applications

摘要

Nanocrystalline and ultra-fine grain copper can potentially offer increased reliability and functionality of printed wiring boards due to expected enhancements in strength and achievable wiring density by grain size reduction. In this research in-house synthesized nanocrystalline and ultra-fine grain-size copper foils produced by pulsed electrodeposition were compared with commercially available electronic grade polycrystalline electrodeposited (EG-ED) and cold rolled annealed (EG-CRA) copper foil. The microstructures of all materials were characterized by transmission electron microscopy (TEM). Nano-indentation and the four-point probe technique were used to evaluate their hardness and electrical resistivity, respectively. It is shown that grain size reduction results in significant increases in hardness at a moderate loss in conductivity.