An EUV lithography system achieves high-resolution printing without the
use of photomasks, projection optics, multilayer mirrors, or an extremely
high-power EUV source. The system comprises a xenon laser-produced-plasma
(LPP) illumination source (requiring 93 W hemispherical EUV emission in
the wavelength range 10 12 nm), all-ruthenium optics (grazing-incidence
mirrors and microlenses) and spatial light modulators comprising
MEMS-actuated microshutters. Two 300-mm wafers are simultaneously exposed
with a single 10 kHz LPP source to achieve a throughput of 6 wafers per
hour, per LPP source. The illumination is focused by the microlens arrays
onto diffraction-limited (42-nm FWHM) spots on the wafer plane, and the
spots are intensity-modulated by the microshutters as they are
raster-scanned across the wafer surface to create a digitally synthesized
exposure image. The optical path between the source and the microlenses
traverses seven grazing-incidence mirrors (two collimator elements and
five fold mirrors), which have high reflection efficiency and essentially
unlimited wavelength bandpass.