| 摘要 |
<p>A wafer, having alignment marks formed thereon, is aligned by radiating a first light beam onto the alignment marks so as to generate a first diffracted light beam. The first diffracted light beam is sensed at a first position. A second light beam is radiated onto the alignment marks so as to generate a second diffracted light beam. The second diffracted light beam is sensed at a second position. A correction value is calculated based on a first difference between the first position and a first predetermined position and a second difference is calculated based on a second difference between the second position and a second predetermined position. The wafer is aligned based on the correction value.</p> |
