| 摘要 |
Apparatus (100) and method (500 for aligning a rotatable substrate (100, 700, 900, 1000, 1 100). In some embodiments, a circumferentially extending timing pattern (400) is formed on a substrate (step 506). The timing pattern nominally extends about a center point (206) of the substrate at a selected radius. The substrate is mounted to a support mechanism (102) which rotates the substrate about a central axis (104). Due to mechanical tolerances, the central axis will be offset from the center point of the substrate as a result of an alignment error during the mounting of the substrate. The offset between the support mechanism central axis and the center point of the substrate is determined using a detector (118) that detects two opposing cross-over transitions (208, 210) of the timing pattern during each revolution of the substrate (step 514). A feature (602, 604, 902, 904, 910) may be written to the substrate by positioning a write element with respect to the substrate responsive to the detected offset (step 516). |
