Enhancing productivity and sensitivity in mask production via a Fast Integrated T+R pattern inspection and STARlight-2~TM contamination inspection on critical layers

摘要

Transmitted Light (ddT or dbT) pattern inspection and STARlight-2~TM (SL2) contamination inspection are widely employed by mask makers in order to detect pattern and contamination defects on photomasks during the mask inspection process. However, such an approach needs a two-pass inspection to detect pattern defects and contamination defects separately. In this paper we introduce the 'Fast Integrated T+R and SL2' capability and investigate the properties of this combination of Transmitted (T) and Reflected ( R ) light inspection on die areas and STASJight-2~TM (SL2) on scribe areas. 'Fast Integrated T+R and SL2' has the capability to reduce a two-pass inspection to a single set-up and single pass inspection resulting in a substantial saving of inspection time. In addition to a throughput enhancement, ‘Fast Integrated T+R and SL2' is able to compliment the pattern T inspection by providing additional sensitivity to detect challenging defects. During this study we collect and analyze inspection data on a critical layer provided by the Advanced Mask Technology Center. Compared to the 2-pass individual mode pattern T and contamination SL2 inspections, a single scan 'Fast Integrated T+R and SL2' demonstrates the capability to capture additional real defects, improves reticle inspectability and first time success rate, and results in a significant enhancement in productivity. Based on empirical data collected in this study, the Fast Integrated T+R and SL2 inspection is able to improve inspection throughput approximately 45% at P90.