| 摘要 |
PROBLEM TO BE SOLVED: To provide an improved metrology method enabling more accurate measurement on smaller targets, a metrology apparatus configured to measure properties of a plurality of targets on a substrate, etc.SOLUTION: A metrology apparatus is arranged to illuminate a plurality of targets with an off-axis illumination mode. Images of the targets are obtained using only one first order diffracted beam. Where the target is a composite grating, overlay measurements can be obtained from the intensity of the images of the gratings. Overlay measurements can be corrected for errors caused by variations in the position of the gratings in an image field. |
