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The coherent scattering microscopy/in-situ accelerated contamination system (CSM/ICS) is a developmental metrology tool designed to analyze the impact of carbon contamination on the imaging performance. It was installed at 11B EUVL beam-line of the Pohang Accelerator Laboratory (PAL). Monochromatized 13.5 nm wavelength beam with Mo/Si multilayer mirrors and zirconium filters was used. The CSM/ICS is composed of the CSM for measuring imaging properties and the ICS for implementing acceleration of carbon contamination. The CSM has been proposed as an actinic inspection technique that records the coherent diffraction pattern from the EUV mask and reconstructs its aerial image using a phase retrieval algorithm. To improve the CSM measurement accuracy, optical and electrical noises of main chamber were minimized. The background noise level measured by CCD camera was approximately 8.5 counts (3 sigma) when the EUV beam was off. Actinic CD measurement repeatability was <1 A (3 sigma) at 17.5 nm line and space pattern. The influence of carbon contamination on the imaging properties can be analyzed by transferring EUV mask to CSM imaging center position after executing carbon contamination without a fine alignment system. We also installed photodiode and ellipsometry for in-situ reflectivity and thickness measurement. This paper describes optical design and system performance observed during the first phase of integration, including CSM imaging performance and carbon contamination analysis results.

The Long Trace Profiler (LTP), an instrument for measuring the slope profile of long X-ray mirrors, has been used for adjusting bendable mirrors. Often an elliptical profile is desired for the mirror surface, since many synchrotron applications involve imaging a point source to a p i n t image. Several techniques have been used in the past for adjusting the profile measured in height or slope of a bendable mirror. Underwood et al. have used collimated X-rays for achieving a desired surface shape for bent glass optics1. Non linear curve fitting using the simplex algorithm was later used to determine the best fit ellipse to the surface under test2. A more recent method uses a combination of least squares polynomial fitting to the measured slope fimctim in order to enable rapid adjustment to the desired shape.The mirror has mechanical adjustments corresponding to the first and second order terms of the desired slope polynomial, which correspond to defms and coma, respectively. The higher order terms are realized by shaping the width of the mirror to produce the optimal elliptical surface when bent. The difference between desired and measured surface slope profiles allows us to make methodical adjustments to the bendable mirror based on changes in the signs and magnitudes of the polynomial coefficients. This technique gives rapid convergence to the desired shape of the measured surface, even when we have no information about the bender, other than the desired shape of the optical surface. Nonlinear curve fitting can be used at the end of the process for fine adjustments, and to determine the over all best fit parameters of the surface. This technique could be generalized to other shapes such as toroids.