| 摘要 |
PROBLEM TO BE SOLVED: To provide an alignment error detection apparatus for detecting a position detection error of an alignment mark due to change of alignment distribution of scattering light from the alignment mark, and to provide an alignment error detection method. SOLUTION: The position of the alignment mark WA is detected by two detection optical systems 10-1 and 10-2 arranged symmetrically to a normal line VL of a wafer W. The sum of detection positions is found by a processor 40. Since the two detection optical systems are symmetrically arranged even when a position deviationΔx of the alignment mark from a reference position occurs, it is erased by finding the sum of the detection positions because positiveness and negativeness of the position deviationΔx are different in the two detection optical systems, but have equal relation of absolute values. Therefore, the sum of the detection positions is constant, and the change amount of the sum of the detection positions is equal to the position detection error caused by alignment change of the scattering light from the alignment mark. COPYRIGHT: (C)2005,JPO&NCIPI |
