IMC suppression and phase stabilization of Cu/Sn-Bi/Cu microbump via Zn doping

摘要

For the advanced 3D-IC application, warpage and low thermal budget requires low temperature soldering for microbumps. Sn-Bi-Zn low temperature solder was studied for its low cost and accessibility. By doping Zn and adding Sn in solder and substrate metallization, not only the solder alloy was strengthened, but the microstructure was improved for better mechanical properties. The stabilization of melting behavior by doping Zn in substrate was analyzed. The exact phase composition was identified by color mapping and the reduction of Kirkendall void was elaborated in this study. (C) 2020 Elsevier B.V. All rights reserved.