Evaluation of lithography printability review in mature node photomask manufacturing

In the photomask manufacturing industry, producing defect-free photomasks is a significant challenge. The processes of defect inspection, repair, and metrology are employed to ensure masks are defect-free. Within this process flow, the Aerial Image Measurement System (AIMS) metrology tool is widely used as the industry’s benchmark for evaluating defect printing impact and determining if a suspected defect requires repair. However, in the mature node photomask manufacturing, the product quantity is large, and the AIMS 248™ loading is heavy, sometimes doing AIMS review for all defects is expensive and time consuming. Thus, a fast, accurate, and economical method is desired which can simulate defect printability on wafer from images captured by photomask inspection tools, as a valuable complementary or backup method for AIMS to reduce the loading and increase the production efficiency. In this paper, we introduce Lithography Printability Review (LPR) to mature technology node mask manufacturing. It can simulate aerial images of defect with low cost, and short cycle time. On the Programmed Defect Mask (PDM), LPR demonstrated obviously improved efficiency without missing critical defects. For the production masks, LPR proved that it can save much time and improve production capacity effectively.