26 July 1999 Higher-order aberration measurement with printed patterns under extremely reduced sigma illumination
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Abstract
Measurement techniques for higher order aberrations of a projection optical system in photolithographic exposure tools have been established. Even-type and odd-type aberrations are independently obtained from printed grouped lines on a wafer by three-beam interference under highly coherent illumination. Even-type aberrations, i.e. spherical aberration and astigmatism, are derived from the best focus position of vertical, horizontal and orthogonal grouped lines by an optical microscope. Odd-type aberrations, i.e. coma and trefoil, are obtained by detecting relative shifts of fine grouped lines to a large pattern by an overlay inspection tool. The qualitative diagnosis for lens aberrations was demonstrated to a krypton fluoride excimer laser scanner.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hiroshi Nomura, Kazuo Tawarayama, Takuya Kohno, "Higher-order aberration measurement with printed patterns under extremely reduced sigma illumination", Proc. SPIE 3679, Optical Microlithography XII, (26 July 1999); doi: 10.1117/12.354348; https://doi.org/10.1117/12.354348
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