Barrier Properties of CVD Mn Oxide Layer to Cu Diffusion for 3-D TSV

The effect of CVD Mn oxide layer as a barrier layer to Cu diffusion for 3-D TSV was characterized. The impact of oxide substrate on the barrier property of a planar Mn oxide was evaluated by XPS method. Planar Mn oxide layer of 20-nm thickness formed over thermal oxide showed an excellent barrier property to Cu diffusion after annealing at 500°C, whereas the Mn oxide over P-TEOS oxide was good enough up to 400°C annealing. On the other hand, the barrier property of Mn oxide upon O3-TEOS oxide was not as good as thermal and P-TEOS oxides. The effect of a vertical Mn oxide layer as a barrier layer to Cu diffusion from Cu TSV was evaluated by C-t analysis. Vertical Mn oxide layer with 20-nm thickness formed on P-TEOS oxide liner in TSV showed better barrier property, when compared with the sputtered Ta barrier layer, up to 400°C annealing condition. However, the barrier property of CVD Mn oxide layer was degraded after annealing at 500°C.