A non-traditional approach to resolving multi-layer process-induced metal voiding

The effective use of SRAM bitmap, end-of-line failure analyses, in-line electron beam defect inspections and focused ion beam (FIB) to identify and resolve an integration-related metal voiding issue is demonstrated in this paper. Because the voiding mechanism was due to a post-metal, multi-layer process interaction, conventional in-line optical defect inspections failed to provide useful information. Electron beam defect inspections and FIB, on the other hand, provided a fast and accurate in-line assessment of the problem, thus enabling a timely resolution of this yield issue