温度对纳米银膏连接的铜电极扩散阻挡层TiW性能的研究

In this study, the copper electrode was prepared, a TiW(20at.%Ti) target was used. TiW was deposited on copper electrode by DC magnetron sputtering as diffusion barrier, and nano-silver paste was considered as soldering paste. The effects of TiW as diffusion barrier for copper electrode was investigated after thermal aging. As the increasing aging temperature, the diffusion characteristics at interface between nano-silver paste and copper electrode have been analyzed. The cross section of interface was investigated using field-emission SEM. The results show that when the aging temperature was within 350℃, the diffusion barrier can work normally, however for the case of aging 120 h at 350℃, the trace of Cu element was found in the nano-silver paste even about 2-3 μm far away from the diffusion barrier, moreover the same phenomenon occurred when aging 24 h at 400℃. For further investigation, the shear strength of aged copper electrode/TiW diffusion barrier/nano-silver paste/TiW diffusion barrier/copper electrode joints was studied and the results show the joints have sufficient strength which is 19.67 MPa even after aging at 400℃ for 24 h.