| 摘要 |
PROBLEM TO BE SOLVED: To perform the effect of the increase in the wavelengths to the maximum limit by detecting the position of the mark by using the detecting beam containing wavelength components of less position detecting error. SOLUTION: The positionΔX'n of a lattice mark obtained by light quantity signals IAn, IBn (n=1, 2, 3) obtained by an interference alignment method by a zero N-order detecting method is detected at each wavelength by circuits SAn and CAn (n=1, 2, 3). The circuit SAn Calculates a step corresponding amountδn based on the change upon relative scanning of the signals IAn, IBn and the designing data of a lattice mark as the residue of the incident light beam at the half wavelength near the mark surface of the step at each wavelength. The circuit SS obtains the detecting position of the lattice mark at the nearest detection wavelength to the ideal detection wavelength based on the step corresponding amountδn and the positionΔX'n of the lattice mark detected at each wavelength. |
