Influence of sidewall roughness on the reliability of 0.20-μm Al RIE wiring

Abstract

Aluminum based wiring is widely used in the back-end-of-line (BEOL) metallization of integrated circuits. In a 256 Mb Dynamic Random Access Memory (DRAM) product, the first level of Al wiring exists at a 0.20-μm groundrule. Performance and reliability issues from these aggressive groundrules result in serious challenges for semiconductor fabrication processing in the BEOL. This paper compares two different sidewall roughness profiles which were created by varying the post-metal etch wet clean. The resulting "rough" and "smooth" sidewall profiles are correlated with the electrical performance and reliability characteristics of the 256 Mb-DRAM product.