Development progress of optics for extreme ultraviolet lithography at Nikon

摘要

The full-field extreme ultraviolet u0001EUVu0002 exposure tool namednEUV1 is integrated and exposure experiments are started with a numeri-ncal aperture of the projection optics of 0.25, and conventional partialncoherent illumination with a coherence factor of 0.8. 32-nm elbow pat-nterns are resolved in a full arc field in static exposure. In a central area,n25-nm line-and-space patterns are resolved. In scanning exposure,n32-nm line-and-space patterns are successfully exposed on a full wafer.nWavefront error of the projection optics is improved to 0.4-nm rms. Flarenimpact on imaging is clarified, dependent on flare evaluation using thenKirk test. Resolution enhancement technology u0001RETu0002 fly-eye mirrors andnreflection-type spectral purity filters u0001SPFsu0002 are investigated to increasenthroughput. High-NA projection optics design is also reviewed