Authors: A. Hirose, T. Itou, T. Ogura
Affilation: Osaka University, Japan
Pages: 426 - 429
Keywords: silver oxide, silver nanoparticle, bonding, ion-migration, gold, Palladium
We have proposed a new bonding process using Ag2O paste composed of Ag2O particles mixed with reduction agent of triethylene glycol (TEG). Ag nanoparticles formed at around 130℃ to 160℃ through the reduction process. Such formed Ag nanoparticles were immediately sintered each other and bonded to a metal substrate. A Au coated Cu specimen was successfully bonded using the Ag2O paste. The joint had superior strength than that using the conventional Pb-rich solders. To improve ion-migration tolerance, Ag2O paste was mixed with Au and Pd microparticles to form sintered Ag-Au and Ag-Pd layer, respectively. While both Au and Pd additions improved the ion-migration tolerance, Au addition had somewhat higher effectiveness. As for the mechanical property of the joints, mixing of second metals resulted in decreasing joint strength. This was caused by agglomeration of the second metals particles disturbing the sintering of Ag layer. Based on the joint strength of conventional Pb-10Sn solder, limitations of mixing ratio for Au and Pd were found to be 8.7vol% and 6.6vol%, respectively. In each case, the ion-migration tolerance was about 2.5 times and 2.0 times as much as that of pure Ag, respectively.
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