Impact of backside Cu contamination in the 3D integration process

The impact of backside Cu contamination during the 3D integration process was investigated and found that Cu diffusion was significantly enhanced by stress relief and wafer thinning. The thermal scattering phenomenon of Cu is inevitable even under a low-temperature assembly process, which also caused Cu contamination. To prevent the Cu contamination, an Ar ion implantation for Cu gettering and a SiN Cu barrier is proposed.