Low Temperature Bonding Process Using Cu Nanoparticles and Mixed Ag–Cu Nanoparticles

Abstract

In order to obtain Cu-to-Cu joints with high strength and ionic migration resistance, low temperature bonding processes (250°C~400°C) using three kinds of Cu nanoparticles (mean particle sizes: d=7.2 nm, 64.8 nm, and 498 nm) or mixed Ag–Cu nanoparticles were studied. With Cu nanoparticles, the Cu-to-Cu joints using 64.8 nm diameter Cu nanoparticles showed the highest strength. With mixed Ag–Cu nanoparticles comprised of Cu nanoparticles (d=498 nm) and Ag nanoparticles (d=7.9 nm), the strength of Cu-to-Cu joints using 50%Ag–50%Cu nanoparticles was higher than that of any other joints using mixed Ag–Cu nanoparticles. The electrodes prepared using mixed 50%Ag–50%Cu nanoparticles showed higher ionic migration resistance than that prepared using Ag nanoparticles only.