Abstract
Traditionally, mask defect analysis has been done through a visual inspection review. As the semiconductor industry moves into smaller process generations and the complexity of mask exponentially increases, “Mask” issues have emerged as one of the main production problems due to their rising cost and long turn-around time. Mask-making specifications related to defects found on advanced masks also becomes more difficult to define due to the complex features involved [e.g. OPC (Optical Proximity Correction), SRAF (Sub Resolution Assist Features), etc.]. The Automatic Defect Severity Scoring (ADSS) module of i-Virtual Stepper System from Synopsys offers a fast and highly accurate software solution for defect printability analysis of advanced masks in a real production environment. In this paper, we present our case study of production pilot run in which the ADSS is used to automatically quantify the impact of a given defect on the surrounding features, basically filtering out killer defects and nuisance defects in terms of production viewpoints to reduce operators’ intervention. In addition, an automation workflow is also tested, in which the production issues, such as the communication feasibility of mask quality control between mask house and wafer fab, are also considered.
