The Inspection Solutions of 3Bar Structure Cu Void in BEOL Advanced Semiconductor Process

In this paper, 3bar structure Cu void defects are detected and monitored by using brightfiled inspection system in 28nm back-end-of-the-line (BEOL) processes. 3bar structure Cu void defects were studied by a novel combination of dedicated scan settings which can help capture defects more efficiently. The spectrum mode, directional electrical field (DEF) and focus offset were chosen as critical parameters. After defect detecting, failure models were studied and the effective defect reduction actions were carried out. Combining effective defect monitor and defect reduction actions can make BEOL yield improve rapidly.