Development of an automated defect repair system utilizing EUV mask property analysis

To expand functionality beyond physical repair, we integrated Photothermal Induced Force Microscopy (PIFM) into the same AFM system. PIFM enables nanoscale chemical analysis by detecting photothermal forces generated by infrared absorption. This allows precise material identification of defects, aiding both corrective action and root-cause analysis. The key functions of mask repair include precise vertical control of the tip in contact with the defect, high XY positioning accuracy, and minimization of system drift. To achieve these capabilities, the system utilizes AFM-based sub-nanometer tip control, laser interferometers for accurate XY position correction, and environmental controls to reduce drift. We confirmed the feasibility of using the combined AFM–PIFM platform for chemically specific defect analysis and targeted removal. This dual-function approach enhances EUV mask lifetime, reduces replacement costs, and supports more robust, in-line-compatible defect management. Our results demonstrate the potential of AFM and PIFM as a next-generation solution for EUV mask maintenance in semiconductor fabrication.