Interfacial reaction of micro Co-P/Solder/Co-P interconnection under large temperature gradients

摘要

In this paper, we established a thermo-migration(TM) set-up and prepared Co-P/Solder/Co-P sandwich structured interconnection with height of 70μm. Interfacial reaction and diffusion of cobalt in cold/hot end were then studied under a temperature gradient over 1188K/cm in micro-interconnects. The initial IMC thickness at Co-P/Sn interface was 5.082μm and 4.659μm, respectively. The CoSn3 interfacial intermetallic compounds (IMCs) present in Co-P/Sn/Co-P interconnection also provide a more stable morphology after the TM test for 720 min. The CoSn3 IMC thickness in cold end and hot end increased to 6.713μm and 5.842μm, respectively. The growth trend of the cold end IMC is significantly higher than that of the hot end, indicating that TM produce a polar effect on the IMC growth at both ends of the micro-interconnects. And the Co-P layer has a significant inhibitory effect on the diffusion of copper atoms. Comparison experiment (Co/Sn/Co interconnection) shows the temperature gradient of 274.6K/cm does not have a significant induction effect on the interface IMC growth.