At the EUV/Photomask Technology SPIE conference in Monterey last year, Lasertec introduced the world’s first high-sensitivity actinic patterned mask inspection and review system for EUV, the ACTIS A150. More details here (open access): https://www.spiedigitallibrary.org/...EUV-lithography/10.1117/12.2538001.full?SSO=1
An interesting finding was that a 0.55 nm height variation of the silica mask substrate is enough to print as a defect. Although this height is about the lattice constant of SiO2, it corresponds to about a 30 degree phase error, which is still significant.
Update: From an earlier result (T. Terasawa et al., "Phase defect printability analyses: dependence of defect type and EUV exposure condition," Proc. SPIE 8322, 83221R (2012)), for 22 nm L/S, an 80 nm FWHM bump defect just 0.25 nm high could still produce a small 2.5% CD error, at -75 nm defocus.
An interesting finding was that a 0.55 nm height variation of the silica mask substrate is enough to print as a defect. Although this height is about the lattice constant of SiO2, it corresponds to about a 30 degree phase error, which is still significant.
Update: From an earlier result (T. Terasawa et al., "Phase defect printability analyses: dependence of defect type and EUV exposure condition," Proc. SPIE 8322, 83221R (2012)), for 22 nm L/S, an 80 nm FWHM bump defect just 0.25 nm high could still produce a small 2.5% CD error, at -75 nm defocus.
Last edited: