Low temperature bonding by sintering of Ag nanoparticle paste with the assistance of MOD

To satisfy the performance gains of the third-generation semiconductors represented by SiC and GaN during use, novel high-temperature operation die-attachment material, Ag, have received extensive attention in power devices for its excellent thermal conductivity and reliability with high-temperature (over 250°C) applications. At present, sintering silver nanoparticles is commonly used to achieve stable die-attach joint in industry. However, the size effect of nanoparticles makes the preparation and storage of very fine nanoparticles (less than 50 nm) extremely difficult, which can increase the cost of paste. In this paper, we introduce a method for preparing sintered solder with MOD (metal organic decomposition) and commercial Ag nanoparticles, which takes the advantage of Ag nucleation of MOD at low temperature to assist commercial Ag nanoparticles in the paste to achieve lower temperature sintering bonding. We used silver oxalate as a precursor and made it complex with 1, 2-diaminopropane to prepare the MOD solution ink. The MOD ink was utilized as additive at low temperature to assist the connection of nanoparticles in the paste to form a strong joint. The results suggest that shear strength of sintering joint can reach 32.7 MPa at 175°C.