| 摘要 |
A method of determining the location of a lithographic substrate relative to an imprint template is disclosed. The method includes positioning the substrate adjacent to the imprint template such that an alignment grating on the substrate and an alignment grating on the imprint template form a composite diffraction grating, directing alignment radiation beam comprising radiation at a first wavelength and radiation at a second wavelength, the second wavelength being longer than the first wavelength, at the composite diffraction grating, detecting radiation diffracted from the composite grating during relative lateral movement between the imprint template and the substrate, using the detected radiation at the second wavelength to obtain information regarding a separation between the substrate alignment grating and the imprint template alignment grating, and using the detected radiation at the first wavelength to obtain information regarding the lateral position of the substrate alignment grating relative to the imprint template alignment grating.
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