| Popis: |
Defect verification has become significantly difficult to higher technology nodes over the years. Traditional primary method of defect (include repair point) control consists of inspection, AIMS and repair steps. Among them, AIMS process needs various wafer lithography conditions, such as NA, inner/outer sigma, illumination shape and etc. It has a limit to analyze for every layer accurately because AIMS tool uses the physical aperture system. And it requires meticulous management of exposure condition and CD target value which change frequently in advanced mask. We report on the influence of several AIMS parameters on the defect analysis including repair point. Under various illumination conditions with different patterns, it showed the significant correlation in defect analysis results. It is able to analyze defect under certain error budget based on the management specification required for each layer. In addition, it provided us with one of the clues in the analysis of wafer repeating defect. Finally we will present 'optimal specification' for defect management with common AIMS recipe and suggest advanced mask process flow. |
