At-wavelength interferometry for extreme ultraviolet lithography
- Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
A phase-shifting point diffraction interferometer is being developed for at-wavelength testing of extreme ultraviolet lithographic optical systems. The interferometer was implemented to characterize the aberrations of a 10{times} Schwarzschild multilayer-coated reflective optical system at the operational wavelength of 13.4 nm. Chromatic vignetting effects are observed and they demonstrate the influence of multilayer coatings on the wave front. A subaperture of the optic with a numerical aperture of 0.07 was measured as having a wave front error of 0.090 wave (1.21 nm) root mean square (rms) at a 13.4 nm wavelength. The wave front measurements indicate measurement repeatability of {plus_minus}0.008 wave ({plus_minus}0.11nm) rms. Image calculations that include the effects of the measured aberrations are consistent with imaging performed with the 10{times} Schwarzschild optic on an extreme ultraviolet exposure tool. {copyright} {ital 1997 American Vacuum Society.}
- OSTI ID:
- 550470
- Report Number(s):
- CONF-9705218--
- Journal Information:
- Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena Journal Issue: 6 Vol. 15; ISSN 0734-211X; ISSN JVTBD9
- Country of Publication:
- United States
- Language:
- English
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