Fig. 1. Schematic diagram of the optical path of the EUV mask imaging analysis system platform at SSRF (a) Conventional circular off-axis zone plate, (b) Anamorphic elliptical off-axis zone plate

Fig. 2. Reflectivity of multilayers on an EUV mask at 13.5-nm wavelength as a function of the angle of incidence (a), apertures of 4×NA=0.625 circle and anamorphic zone plate at 10° in comparison and range of angles of the associated ray cones (b)

Fig. 3. Imaging of circular off-axis zone plates with 4×NA=0.625 (color online) (a) Mask hp=22 nm, (b) hp=20 nm imaging under horizontal extreme dipole illumination, (c) hp=22 nm imaging under horizontal extreme dipole illumination, (d) hp=26 nm imaging under horizontal extreme dipole illumination, (e) The cross-section distribution curve of imaging results (section position y=0 nm)

Fig. 4. Imaging of two dimension L-shaped mask (color online) (a) L-shaped mask hp=22 nm, (b) Mask imaging under annular illumination, (c) Mask imaging under extreme quadrupole illumination, (d) The cross-section distribution curve of imaging results (section position x=60 nm, y=60 nm)

Fig. 5. Elliptical off-axis zone plate imaging with anisotropic numerical aperture (color online)(a) Mask hp=12 nm, (b) Imaging of hp=12 nm with 4×NA=1.15 and 0.575, (c) Imaging of hp=14 nm with 4×NA=1.0 and 0.5, (d) Imaging of hp=14 nm with 4×NA=0.94 and 0.625, (e) The cross-section distribution curve of imaging results for hp=12 nm (y=0 nm), (f) The cross-section distribution curve of imaging results for hp=14 nm (section position y=0 nm)

Fig. 6. Elliptical off-axis zone plate imaging with anisotropic numerical aperture (color online) (a) Two dimension L-shaped mask, vertical direction hp=12 nm, horizontal direction hp=24 nm, (b) Mask imaging under annular illumination, (c) Mask imaging under extreme quadrupole illumination, (d) The cross-section distribution curve of imaging results of hp=12 nm (y=60 nm), (e) The cross-section distribution curve of imaging results of hp=24 nm (section position x=120 nm)

Fig. 7. Elliptical off-axis zone plate imaging with anisotropic numerical aperture (color online) (a) Two dimension L-shaped line pairs, with hp=24 nm in both directions, (b) Uniform intensity quadrupole illumination pupil pattern, (c) Light intensity distribution 1:20 quadrupole illumination pupil pattern, (d~f) Imaging results of quadrupole illumination corresponding to light intensities of 1:1, 1:5, and 1:20, (g) The cross-section distribution curve of imaging results (section position x=0 nm, y=80 nm)