At-wavelength characterization of the extreme ultraviolet Engineering Test Stand Set-2 optic

At-wavelength interferometric characterization of a new 4x-reduction lithographic-quality extreme ultraviolet (EUV) optical system is described. This state-of-the-art projection optic was fabricated for installation in the EUV lithography Engineering Test Stand (ETS) and is referred to as the ETS Set-2 optic. EUV characterization of the Set-2 optic is performed using the EUV phase-shifting point diffraction interferometer (PS/PDI) installed on an undulator beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. This is the same interferometer previously used for the at-wavelength characterization and alignment of the ETS Set-1 optic. In addition to the PS/PDI-based full-field wavefront characterization, we also present wavefront measurements performed with lateral shearing interferometry, the chromatic dependence of the wavefront error, and the system-level pupil-dependent spectral-bandpass characteristics of the optic; the latter two properties are only measurable using at-wavelength interferometry.

[1]  A. B. Bhatia,et al.  LETTERS TO THE EDITOR: The Zernike Circle Polynomials Occurring in Diffraction Theory , 1952 .

[2]  Kenneth A. Goldberg,et al.  Extreme ultraviolet alignment and testing of a four-mirror ring field extreme ultraviolet optical system , 2000 .

[3]  Kenneth A. Goldberg,et al.  Adding static printing capabilities to the EUV phase-shifting point diffraction interferometer , 2001, SPIE Advanced Lithography.

[4]  Kenneth A. Goldberg,et al.  Extreme ultraviolet carrier-frequency shearing interferometry of a lithographic four-mirror optical system , 2000 .

[5]  Kenneth A. Goldberg,et al.  Extreme ultraviolet interferometric measurements of diffraction-limited optics , 1999 .

[6]  Donald W. Sweeney,et al.  Rigorous method for compensation selection and alignment of microlithographic optical systems , 1998, Advanced Lithography.

[7]  Pei-yang Yan,et al.  System integration and performance of the EUV engineering test stand , 2001, SPIE Advanced Lithography.

[8]  G. E. Sommargren,et al.  Phase Shifting Diffraction Interferometry for Measuring Extreme Ultraviolet Optics , 1996, Extreme Ultraviolet Lithography (TOPS).

[9]  J. Bokor,et al.  Phase-shifting point diffraction interferometer. , 1996, Optics letters.

[10]  A. A. MacDowell,et al.  Phase‐measuring interferometry using extreme ultraviolet radiation , 1995 .

[11]  K A Goldberg,et al.  Phase effects owing to multilayer coatings in a two-mirror extreme-ultraviolet schwarzschild objective. , 1998, Applied optics.

[12]  J. Underwood,et al.  Layered synthetic microstructures as Bragg diffractors for X rays and extreme ultraviolet: theory and predicted performance. , 1981, Applied optics.

[13]  S. H. Lee,et al.  Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy. , 1999, Applied optics.

[14]  Kenneth A. Goldberg,et al.  Extreme ultraviolet interferometry , 1997 .

[15]  Erik H. Anderson,et al.  Electron beam lithography digital pattern generator and electronics for generalized curvilinear structures , 1995 .

[16]  N. Ceglio,et al.  Undulator radiation for at-wavelength interferometry of optics for extreme-ultraviolet lithography. , 1993, Applied optics.

[17]  Jonathan L. Cobb,et al.  Demonstration of pattern transfer into sub-100 nm polysilicon line/space features patterned with extreme ultraviolet lithography , 1999 .

[18]  Donald W. Sweeney,et al.  EUV optical design for a 100-nm CD imaging system , 1998, Advanced Lithography.