We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Influence of cerium oxide (CeO) nanoparticles on the microstructure and hardness of tin-silver-copper (Sn-Ag-Cu) solders on silver (Ag) surface-finished copper (Cu) substrates.
- Authors
Fouzder, Tama; Chan, Y.; Chan, Daniel
- Abstract
Nano-sized, non-reacting, non-coarsening CeO particles with a density close to that of solder alloy were incorporated into Sn-3.0 wt%Ag-0.5 wt%Cu solder paste. The interfacial microstructure and hardness of Ag surface-finished Cu substrates were investigated, as a function of reaction time, at various temperatures. After the initial reaction, an island-shaped CuSn intermetallic compound (IMC) layer was clearly observed at the interfaces of the Sn-Ag-Cu based solders/immersion Ag plated Cu substrates. However, after a prolonged reaction, a very thin, firmly adhering CuSn IMC layer was observed between the CuSn IMC layer and the substrates. Rod-like AgSn IMC particles were also clearly observed at the interfaces. At the interfaces of the Sn-Ag-Cu based solder-Ag/Ni metallized Cu substrates, a (Cu, Ni)-Sn IMC layer was found. Rod-like AgSn and needle-shaped CuSn IMC particles were also observed on the top surface of the (Cu, Ni)-Sn IMC layer. As the temperature and reaction time increased, so did the thickness of the IMC layers. In the solder ball region of both systems, a fine microstructure of AgSn, CuSn IMC particles appeared in the β-Sn matrix. However, the growth behavior of the IMC layers of composite solder doped with CeO nanoparticles was inhibited, due to an accumulation of surface-active CeO nanoparticles at the grain boundary or in the IMC layers. In addition, the composite solder joint doped with CeO nanoparticles had a higher hardness value than the plain Sn-Ag-Cu solder joints, due to a well-controlled fine microstructure and uniformly distributed CeO nanoparticles. After 5 min of reaction on immersion Ag-plated Cu substrates at 250 °C, the micro-hardness values of the plain Sn-Ag-Cu solder joint and the composite solder joints containing 1 wt% of CeO nanoparticles were approximately 16.6 and 18.6 Hv, respectively. However after 30 min of reaction, the hardness values were approximately 14.4 and 16.6 Hv, while the micro-hardness values of the plain Sn-Ag-Cu solder joints and the composite solder joints on Ag/Ni metallized Cu substrates after 5 min of reaction at 250 °C were approximately 15.9 and 17.4 Hv, respectively. After 30 min of reaction, values of approximately 14.4 and 15.5 Hv were recorded.
- Subjects
SOLDER &; soldering; CERIUM oxides; HARDENABILITY of metals; METAL microstructure; INTERMETALLIC compounds; NANOPARTICLES; SURFACE finishing
- Publication
Journal of Materials Science: Materials in Electronics, 2014, Vol 25, Issue 12, p5375
- ISSN
0957-4522
- Publication type
Article
- DOI
10.1007/s10854-014-2316-1