Title:
EQUIPMENT FOR MEASURING SUPERPOSITION ERROR
Document Type and Number:
Japanese Patent JP2003022954
Kind Code:
A
Abstract:
To provide an equipment for measuring superposition error in which the image of an inspection mark can be obtained with a high contrast and the work efficiency and the measurement accuracy can be enhanced.
When the difference in the brightness of reflected light is small and the contrast of the image of an inspection mark 3 is insufficient, superposition error is calculated based on the image of the inspection mark subjected to gamma correction. Since the gamma value being set is required to make conspicuous the contrast by increasing the level of original brightness, a value lower than 1 (e.g. 0.2) is selected.
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Inventors:
ARIMA HIROFUMI
Application Number:
JP2001207345A
Publication Date:
January 24, 2003
Filing Date:
July 09, 2001
Export Citation:
Assignee:
NIKON CORP
International Classes:
G01B11/00; G01B11/24; G06T1/00; G06T7/60; H01L21/027; H01L21/66; (IPC1-7): H01L21/027; G01B11/00; G01B11/24; G06T1/00; G06T7/60; H01L21/66
Attorney, Agent or Firm:
Shogo Onishi
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