Low-temperature and Pressureless Sintering Technology for High-performance and High-temperature Interconnection of Semiconductor Devices

We present an interconnect technology based on low-temperature and pressureless sintering of a nanoscale metal paste to achieve high-performance and high-temperature packaging of semiconductor devices. The nanoscale metal paste, consisting of nanoparticles of silver mixed in an organic binder/solvent vehicle, can be sintered at temperatures close to 275degC. Measurements on electrical and thermal properties of the sintered die interconnect gave it at least five times better than the soldered or epoxied attachment. Die-shear tests of the sintered joints showed a bonding strength of about 25 MPa. The sintered joints exhibited excellent reliability in aging and temperature-cycling tests. Since silver melts at 961degC, the sintered interconnect can be used for wide band gap semiconductor devices (SiC or GaN), which are operable over 300degC where none of the existing solder alloys or epoxies can be used. In summary, the low- temperature sintering of nanoscale metal paste is shown to be a reliable, lead-free interconnect solution for high-temperature and high-performance packaging needs.