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Proceedings Paper

Submicrometer Pattern Correction For Optical Lithography
Author(s): Tetsuo Ito; Kazuya Kadota; Hiroshi Fukui; Masaki Nagao; Aritoshi Sugimoto; Masahiro Nozaki; Takeshi Kato
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Paper Abstract

To realize higher CD controls of submicrometer devices, the submicrometer pattern corrections were investigated in optical reduction steppers considering the primary residual aberrations. The optical pattern fidelities on the reduction pattern transfer were estimated at first using the three-dimensional photoresist image simulator RESPROT (Resist Process Three-Dimensional Simulator), which is examined the Seidel's primary aberrations, i.e. spherical aberration, astigmatism, field curvature, distortion and coma. From RESPROT calculations it was known that astigmatism affects pattern shape depending on image height, coma and distortion make position shifts in exposure field, and image contrast is influenced by field curvature. These results were reflected to device design rules, process latitude enhancements and lens manufacturings. To use premature high NA g-line lenses and minimize the diffraction limit for submicrometer area, reticle pattern corrections are very useful for sub-space patterns writing in contact holes, "tailoring" of W/L for MOS-gate patterns, and sub-field position control for distortion correction on ER writing. For almost of this investigation, 5-10nm order corrections were required from original design on wafer. In order to make good use of higher NA lenses, focus latitude enhancement are required because field curvature control is very severe. For these demand, multi-step superpositions of focus and exposure, FLEX -method, is useful to enhance the depth of focus effectively. These simulated and examined results are covenient to realize submicrometer devices on advantageous optical lithography using more shorter wavelength, i.e. i-line or excirner laser steppers.

Paper Details

Date Published: 1 January 1988
PDF: 9 pages
Proc. SPIE 0922, Optical/Laser Microlithography, (1 January 1988); doi: 10.1117/12.968397
Show Author Affiliations
Tetsuo Ito, Hitachi ltd (Japan)
Kazuya Kadota, Hitachi ltd (Japan)
Hiroshi Fukui, Hitachi ltd (Japan)
Masaki Nagao, Hitachi ltd (Japan)
Aritoshi Sugimoto, Hitachi ltd (Japan)
Masahiro Nozaki, Hitachi ltd (Japan)
Takeshi Kato, Hitachi. ltd (Japan)

Published in SPIE Proceedings Vol. 0922:
Optical/Laser Microlithography
Burn Jeng Lin, Editor(s)

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