Low-Temperature Sintered Silver Attachment for High-Temperature Operation of SiC Power Devices

In this paper, we present a novel die-attach solution based on low-temperature sintering of nanosilver paste for high-temperature operation of SiC power devices. The nanosilver paste was prepared by mixing silver nanoparticles with an organic binder system. SiC Schottky diodes were die-attached onto direct-bond-copper (DBC) substrates using the stencil- or screen-printed nanosilver paste layers with thickness 1~2 mil. After holding at 300deg C for about 40 minutes to burn out all the organic components, the nanosilver paste consolidated into strong and uniform die-attach bonding with either silver- or gold-coated DBC substrates. Then, the silver die-attached SiC devices were cooled down to room temperature and their top terminals were gold wire-bonded for fulfilment of the high-temperature power packages. Finally the interconnected SiC devices were heated up from room temperature to the highest toleration points of the devices for the high-temperature operation and characterization. Results of the measurements demonstrated that the low-temperature sintering technique is an effective die-attach solution for high-temperature electronics.