摘要 |
A system and method for aligning a wafer in an exposure apparatus includes a holder adapted to hold a wafer (the wafer includes alignment marks), a coarse alignment system, and a fine alignment system having a higher precision than the coarse alignment system. The fine alignment system includes multiple optical detectors. Each of the optical detectors is positioned to detect a corresponding alignment mark on the wafer. An alignment processor is connected to and controls the optical detectors and the holder. The optical detectors are controlled by the alignment processor to simultaneously detect the alignment marks in parallel operations. Further, the alignment processor simultaneously processes signals from the optical detectors in parallel operations.
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