Effects of (002) β-Ta barrier on copper chemical mechanical polishing behavior

This study proposes that the corrosion resistance of copper film correlates well with underlying barrier's orientation. To test the hypothesis, we performed X-ray diffraction, conducted copper removal rate experiments after chemical mechanical polishing, and tested static potentiodynamic polarization. The results all show that copper deposited on strongly (002) oriented β-Ta barrier layer demonstrated better chemical resistance against surface reaction with the slurry for strong copper (111) orientation. The findings were consistent with the result of the chronoamperometric test at 0.3 V in which the more passive film formed on the composite film with (002) β-Ta underlying barrier.

► (111) oriented copper electrodeposited on (002) ß-Ta barrier layer.
► (111) copper has good chemical resistance.
► Reduced surface reaction on (111) copper affected the polishing rate.
► (111) copper on (002) ß-Ta barrier layer had low removal rate.