| 摘要 |
PURPOSE: A method for measuring alignment is provided to be capable of improving the accuracy of the alignment. CONSTITUTION: A wafer is loaded on a wafer stage, wherein the wafer stage is capable of rotating(S501). At this time, a plurality of alignment marks are formed on the upper portion of the wafer. The position of the alignment marks is measured by using overlay beam(S502). After rotating the wafer as much as 180 degrees, the position of the alignment marks is measured again(S503). Alignment result is corrected by comparing the two measured results with each other(S504). Preferably, the wafer stage has a rotating angle of 0-180 degrees. Preferably, the wafer stage is capable of rotating at the rotating angle of 90-270 degrees.
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