26 July 1999 Novel aberration monitor for optical lithography
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The aberration monitor allows independent determination of spherical, coma, astigmatism and three point in a single experiment using existing equipment. The monitor consists of a circular phase object, with a diameter of approximately (lambda) /NA and a phase depth of (lambda) /2. Due to the relative large diameter, the image prints as a narrow ring into the resist. Without aberrations its contours are concentric circles. Aberrations deform the ring in a characteristic way. A detailed analysis of the ring shape through focus identifies the aberrations of the projection lens. A linear aberration model is compared with simulations. Experimental results of various aberrations are shown and ar correlated to line width measurements and interferometric lens data.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Peter Dirksen, Casper A. H. Juffermans, Rudy J. M. Pellens, Mireille Maenhoudt, Peter De Bisschop, "Novel aberration monitor for optical lithography", Proc. SPIE 3679, Optical Microlithography XII, (26 July 1999); doi: 10.1117/12.354385; https://doi.org/10.1117/12.354385

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