Nano-metal sintering has been proven to be a promising die attachment technology for power electronics packaging in the high-end application. Compared with nano silver technology, it is believed that copper-based sintering technology has better cost and performance superiority, and thus has more potential to be utilized in the industry in the future. However, most of the current developed nano copper sintering material and technology shows bad performance with high sintering energy input. In this study, a novel nano-copper based paste has been developed with excellent process ability (sinterable below 280°C for 10 min with low pressure assisted) and good material property (over 40 MPa shear strength), which turns out to be suitable for the state-of-the-art packaging process. Then the material was applied into a SiC power module packaging scenario which shows comparable performance as silver sintering. The whole process only consumed less than 0.5h for each batch, which indicates that the copper sintering technology has great potential for the packaging application in high power situation.@en

A systematic study of discrete SiC MOSFETs' reliability under High Temperature stress has been carried out. High Temperature stress is performed in this work to characterize the threshold voltage instability. To investigate the degradation mechanism of devices, simulation according to the structure of MOSFET cell has been performed. The result shows that the threshold voltages change trends of both MOSFETs are the same, including drop-down period at very early time due to a decrease of doping concentration at channel region and gradual raise-up period at in the rest of time resulting from decline of interface charge.@en

As an outstanding corrosion inhibitor for copper, the adsorption behavior of benzotriazole on copper nano cluster has been investigated and compared with copper (111), (100) and (110) surfaces by means of density functional theory (DFT) calculations. Calculations reveal that benzotriazole has chemical adsorption on different copper surfaces and copper nano cluster when its N2-N3 bond is placed down on them. Also, the adsorption energy and closest interatomic distance show strong dependence on the surface structure, which indicates its ability to passivate the reactive under-coordinated surface sites. Relatively strong chemical bond between the copper cluster and the adsorbate is found to form. The chemisorption mechanism and the local structure of benzotriazole on copper surfaces and nano cluster are also discussed and presented.@en

Nano-metal sintering is a promising technology for the next generation of semiconductor packaging due to its positive effect on reliability enhancement. Compared with the silver sintering, copper-based sintering technique has more potential to be applied in die attachment field as its superiorities on lower cost, higher melting temperature without electromigration. In this study, Taguchi method is applied to study and analyze the effect of nano-/micro- particle ratio on sintering properties. Sintering temperature is also taken into account since it depends on the particle size a lot. The results show that both sintering temperature and nano-micro- ratio play significant role on influencing shear strength. The best combination is 300 nm with 1 um mixing (1:1) with over 35 MPa shear strength with 300°C sintering temperature. The fracture surface result shows that the crack propagated in the sintering body. Furthermore, the cross-section inspection reveals dense bonding and clearly sintering necking, and the porosity is lower than 12%. 227.8 W/m*K thermal conductivity and 6.0 uΩ·cm electrical resistivity are measured for the sample, which indicates the great potential for the packaging application in high power situation.@en