PVD- Treated ALD TaN for Cu Interconnect Extension to 5nm Node and Beyond

Abstract

We report a novel approach to enable thin (≤15Å) ALD-based TaN barriers. The use of a post-ALD treatment in a PVD chamber resulted in ALD films with resistivity, density and Ta/N ratio similar to industry-standard PVD TaN. This approach enables conformal Cu barrier without reliability degradation compared to PVD TaN. This new approach overcomes the shadowing effect of the traditional PVD approach, improves the metal-fill process window, and promotes lower via resistance through barrier thickness reduction, proving it to be a viable Cu-barrier candidate for 5nm node and beyond.