Grain size stability of interfacial intermetallic compound in Ni and Co nanoparticle-doped SAC305 solder joints under electromigration

• Main Authors: Bashir, M. Nasir, Haseeb, A. S. M. A.
• Format: Article
• Published: Springer 2022
• Subjects: TJ Mechanical engineering and machinery; TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.um.edu.my/42155/
• Institution: Universiti Malaya

In Sn-based solder joints, the size of interfacial IMC grains plays an important role in determining the properties of solder joints. An effort has been made to investigate the effects of Ni and Co nanoparticles (NP)-doped flux on the grain size of interfacial intermetallic compound (IMC) in SAC305 solder joints under electromigration (EM). The EM tests were conducted on undoped SAC305 and NP-doped SAC305 solder joints. EM tests were run in an oil bath at a temperature of 80 degrees C for a maximum time of 1128 h. A constant DC current was applied to achieve a current density of 1 x 104 A/cm(2). The information about grain size of interfacial IMC was obtained by electron backscatter diffraction (EBSD). Results reveal that the addition of 2 wt% Ni and Co NP-doped flux in the SAC305 solder joint significantly reduced the grain size of interfacial IMC after the reflow process. The grain size of interfacial IMC decreased 33.33% for Ni-added and 22.22% for Co-added solder joint after the reflow process compared to the undoped solder joint. During EM, the grains remained small at the cathode sides while they rapidly grew at the anode side in the undoped solder joints. In the case of Ni and Co NP-doped samples, no significant change in IMC grain size was found at the cathode and the anode sides after EM. The use of Ni and Co NP-doped flux thus minimized the effects of EM by stabilizing the interfacial IMC.