Nano-Cu Sintering Paste for High Power Devices Die Attach Applications
Authors: Jinjin Zhao, Min Yao, Ning-Cheng Lee Company: Indium Corporation Date Published: 9/17/2017
Abstract: For high power die attach applications, high-lead solder alloys have been the incumbent choice for decades. However, with RoHS lead-free regulation enforcement plus the trend toward a higher service temperature and a higher thermal and electrical conductivity, the high-lead solder is deemed to be phased out. Among the lead-free alternatives, nano-Ag-sintering paste has been one attractive candidate, except the potential concern on the risk of Ag migration and the high cost of Ag. For instance, Ag-migration has been observed for LED flip chip interconnect with 200 micron spacing. Furthermore, use of nano-Ag paste on non-noble metal surface finishes typically resulted in poor bond strength or poor reliability. In view of these, nano-Cu-sintering paste appears to be one obvious contender. In this work, a nano-Cu sintering paste with high oxidation resistance has been developed. The characteristics of Cu particles, its sintering capability, storage life, bond strength, and reliability at TCT test will be discussed.
Nano Cu, paste, pressureless, sintering, die attach, high power