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Influences of the inclination of gratings on the alignment accuracies in moiré alignment systems
Author(s) -
Furuhashi Hideo,
Zhou Lizhong,
Liu Jingnan,
Matsuo Akihito,
Uchida Yoshiyuki
Publication year - 2002
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.1152
Subject(s) - moiré pattern , lithography , wafer , materials science , optics , grating , point (geometry) , optoelectronics , physics , geometry , mathematics
In the lithographic processes of VLSIs, high setting accuracies between masks and wafer are required. The methods using moiré signals obtained by gratings were found to give very high alignment accuracies. In this paper, influences of the inclination of gratings for the alignment accuracies in modified and differential moiré systems have been investigated. The moiré signals and the alignment point have been calculated using computer simulation. As a result, it has been shown that the effects are small and the inclinations do not affect alignment accuracies in the moiré alignment systems. © 2002 Scripta Technica, Electr Eng Jpn, 139(2): 46–51, 2002; DOI 10.1002/eej.1152