Ultrasonic powder consolidation of Sn/In nanosolder particles and their application to low temperature Cu-Cu joining

Yang Shu, Somayeh Gheybi Hashemabad, Teiichi Ando, Zhiyong Gu
2016 Materials & design  
Tin/Indium (Sn/In) nanosolder particles in the size range of 40-70 nm were successfully consolidated into nanosolder films by the ultrasonic power consolidation (UPC) method. The consolidated nanosolder film prevents the nanoparticles from oxidation, which is a common problem of nanomaterials during storage and processing, and makes the nanoparticles easier to handle. The quality of the consolidated nanosolders was examined by scanning electron microscopy (SEM),X-ray diffraction (XRD), and
more » ... ion (XRD), and differential scanning calorimetry (DSC). The consolidated Sn/In nanosolder films were then used to join copper (Cu) plates at two soldering conditions (high pressure vs. low pressure). SEM and energy dispersive X-ray spectroscopy (EDS) were used to study the intermetallic compound (IMC) formation and growth during thermal aging. The IMC layer consisted of ƞ-Cu6(Sn, In)5 and no Cu3(Sn, In) was observed. The thickness of the IMC layer followed a linear relationship with the square root of the aging time, indicating diffusion controlled kinetics. The results indicated that pressure is critical for effective Cu-Cu joining by limiting the IMC growth. Finally, pull tests of the specimen joined by the consolidated nanosolder film under high pressure showed a comparable result with the solder joints formed by Sn/In solders reported in literature.
doi:10.1016/j.matdes.2016.09.013 fatcat:etp5gopjuzf5pglgqfmhavj3dq