Recent advances in EUV phase-shifting point diffraction interferometry

The extreme ultraviolet (EUV) phase-shifting point diffraction interferometer (PS/PDI) was developed and implemented at Lawrence Berkeley National Laboratory to meet the significant measurement challenge of characterizing EUV projection lithography optics. The PS/PDI has been in continuous use and under ongoing development since 1996. Here we describe recent improvements made to the interferometer, and we summarize metrology results from state-of-the-art 10x-reduction EUV projection optics.

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

[2]  Eric M. Gullikson,et al.  High flux undulator beamline optics for EUV interferometry and photoemission microscopy , 1996, Optics & Photonics.

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

[4]  G. E. Sommargren.  Diffraction methods raise interferometer accuracy , 1996 .

[5]  R. N. Smartt,et al.  Theory and Application of Point-Diffraction Interferometers , 1975 .

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

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

[8]  Eric M. Gullikson.  Scattering from normal-incidence EUV optics , 1998, Advanced Lithography.

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

[10]  Kenneth A. Goldberg,et al.  A 3-D Numerical Study of Pinhole Diffraction to Predict the Accuracy of EUV Point Diffraction Interferometry , 1995 .

[11]  K. Goldberg,et al.  Dual-domain point diffraction interferometer. , 1999, Applied optics.

[12]  Donald M. Tennant,et al.  Alignment of a multilayer‐coated imaging system using extreme ultraviolet Foucault and Ronchi interferometric testing , 1995 .

[13]  Saša Bajt,et al.  Multilayer reflective coatings for extreme-ultraviolet lithography , 1998, Advanced Lithography.

[14]  Jeffrey Bokor,et al.  Direct comparison of EUV and visible-light interferometries , 1999, Advanced Lithography.

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

[16]  Kenneth A. Goldberg,et al.  Interferometric at-wavelength flare characterization of extreme ultraviolet optical systems , 1999 .

[17]  D. J. Brangaccio,et al.  Digital wavefront measuring interferometer for testing optical surfaces and lenses. , 1974, Applied optics.

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

[19]  R. Crane.  Interference phase measurement , 1991 .

[20]  M. Takeda,et al.  Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry , 1982 .

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

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

[23]  Kenneth A. Goldberg,et al.  The EUV phase-shifting point diffraction interferometer , 2001 .

[24]  Kenneth A. Goldberg,et al.  At-wavelength interferometry for extreme ultraviolet lithography , 1997 .

[25]  Kenneth A. Goldberg,et al.  Tunable coherent radiation in the soft X-ray and extreme ultraviolet spectral regions , 1999 .

[26]  Kenneth A. Goldberg,et al.  Characterization of the accuracy of EUV phase-shifting point diffraction interferometry , 1998, Advanced Lithography.