Tracking defectivity of EUV and SADP processing using bright-field inspection

The purpose of this study is to understand EUV+SADP defectivity in 15nm line and space (L&S) pattern, and to examine bright-field inspection capabilities at the 1Xnm node. Programmed defects of known size, shape, and location were printed in dense patterned areas using EUV lithography at IMEC. To track these defects throughout development, a defectivity study was conducted using bright-field inspection after four SADP processing steps. The smallest defect routinely detected had a programmed size of 14nm, and the defect signal was enhanced using polarized light. By comparing defect locations at the beginning and end stages of development, it was found that 95% of defects remained the same. This illustrates the importance of post-lithography wafer inspection. This research shows how defect characteristics on the EUV mask affect the final pattern and demonstrate the sensitivity of bright-field inspection at the 1Xnm node.