Yoshiyuki Sato

Defect criticality index (DCI): a new methodology to significantly improve DOI sampling rate in a 45nm production environment

Increasing inspection sensitivity may be necessary for capturing the smaller defects of interest (DOI) dictated by reduced minimum design features. Unfortunately, higher inspection sensitivity can result in a greater percentage of non-DOI or nuisance defect types during inline monitoring in a mass production environment. Due to the time and effort required, review sampling is usually limited to 50 to 100 defects per wafer. Determining how to select and identify critical defect types under very low sampling rate conditions, so that more yield-relevant defect Paretos can be created after SEM review, has become very important. By associating GDS clip (design layout) information with every defect, and including defect attributes such as size and brightness, a new methodology called Defect Criticality Index (DCI) has demonstrated improved DOI sampling rates.