高温実装用Ni ナノ粒子ダイアタッチ材の接合プロセスと信頼性の検討

抄録

  A process condition and reliability of die-attach technique using Ni-nanoparticles for high temperature electronics was investigated. Use of Ni for die-attach material decrease thermal stress induced by the difference of coefficient of thermal expansion and improve the bonding strength of the joints, because the coefficient of thermal expansion of Ni is between that of Si or SiC device and Cu substrate. In the case of the die-attach technique,‘two-step sintering’, the temperature of second-step sintering must be higher than a reduction temperature of NiO which was formed on surface of Ni-nanoparticle before sintering. In order to optimize the process conditions of the two-step sintering, in particular, the temperature of second-step sintering, the behavior of NiO reduction has been investigated by bonding strength, thermal analysis, and TEM observation. As a result, the joints using two-step sintering technique has superior reliability on thermal cycle test with -40/+250°C.