Advanced absorber and compensation repair for EUV reticles utilizing a novel e-beam-based repair technique

The introduction of EUV photomasks has posed significant challenges in defect repair over the years. Defects within the unique multi-layer stack used for the reflective optics can easily lead to printing defects on the wafer. Although absorber compensation repair has been successfully demonstrated in high-volume manufacturing (HVM), it has been accompanied by several obstacles. Next-generation EUV lithography for high numerical aperture (NA) EUV photomasks is proving more difficult due to stringent requirements. The advanced scanner optics demand more precise edge control for photomask repairs, necessitating the incorporation of resist effects in the defect review process to better emulate wafer impact.