Low-k Dielectric Breakdown Improvement with Co(W,P) Cap Barrier

Abstract

In summary, the implementation of a Co(W,P) cap only on the Cu lines is able to improve the dielectric breakdown performance in Cu/low-k interconnects. This is due to the elimination of the weak interface between the cap and the low-k dielectric. However, the thickness of the Co(W,P) cap needs to be optimized in order to fully benefit from the breakdown improvement while maintaining its efficiency as a Cu diffusion barrier. The leakage mechanism for the SiN cap is deduced to be Poole-Frenkel emission while the leakage mechanism for the Co(W,P) cap is likely to be Schottky emission