Moiré signals in reflection

V. T. Chitnis, Y. Uchida, K. Hane, S. Hattori

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

One of the recent applications of the moiré interferometric technique is in mask alignment for lithography. Usually it is necessary to use reflection moiré systems for alignment. We have analysed theoretically and experimentally the behaviour of moiré signals in reflection, as well as in transmission, with the gap as parameter. A periodic variation of the contrast of the moiré signals was observed when the gap was varied within the Fresnel region. The moiré signals were found to be superimposed on a background which varies with the gap. This variation of background was different for reflection and transmission. However, in both cases the alignment signal itself in the alignment method we are proposing, is independent of small variations in the gap between the two gratings.

Original languageEnglish
Pages (from-to)207-211
Number of pages5
JournalOptics Communications
Volume54
Issue number4
DOIs
Publication statusPublished - 1985 Jun 15
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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    Chitnis, V. T., Uchida, Y., Hane, K., & Hattori, S. (1985). Moiré signals in reflection. Optics Communications, 54(4), 207-211. https://doi.org/10.1016/0030-4018(85)90292-5