| 摘要 |
PURPOSE: To calculate a base line error without performing pre-exposure. CONSTITUTION: An alignment mark AX on a wafer 11 is first detected to obtain an alignment error X1 in an X-direction. After the wafer 11 is rotated by 180 deg., the same alignment mark AX is detected to obtain an alignment error X2 in the X-direction. Then, by calculating (X1+X2)/2, a base line error XB in the X-direction can be obtained. A base line error YB in a Y-direction is also obtained by similar means. With the base line errors XB, YB compensated, alignment of the wafer 11 is performed. |
