The Fabrication of Ni-MWCNT Composite Solder and Its Reliability Under High Relative Humidity and Temperature

Ni decorated multi-walled carbon nanotube (Ni-MWCNT) composite solders have been fabricated using Ni-MWCNT composite materials and Sn58Bi solder alloys. Ni-MWCNT composite materials were synthesized with functionalization, reduction and electroless plating. The Ni-MWCNT composite solders were fabricated at various weight percentages (0, 0.05, 0.1 and 0.2 wt.%) of Ni-MWCNT. The mechanical properties of Ni-MWCNT composite solder were evaluated using ball shear tests. The shear strength and fracture energy were improved about 16.02% and 12.60%, respectively, by adding 0.1 wt.% of Ni-MWCNTs, which released the stress in the solder alloy. The environmental reliability was examined at 85°C with 85% relative humidity at various holding times. After environmental reliability testing, the microstructure was analyzed to characterize the grain and intermetallic layers. The growth of grains and intermetallic layer thickness were mitigated by Ni-MWCNTs in the solder matrix that affected the mechanical properties. The distribution of Ni-MWCNTs inside the solder joints was confirmed by EPMA and Raman spectroscopy.