| 摘要 |
Patterning provided by a lithographic apparatus is optically corrected for focus errors that would result from a topology of a substrate being patterned. Focus control is provided in a cross-scan direction by bending a reticle about a scan axis based on a mapped topology of the substrate. The bending can be updated from field to field as the reticle is scanned. The bending may be unidirectional (e.g., down only), but an optical compensation element (e.g., a lens or mirror polished to a cylindrical shape or a transparent plate or mirror bent by a force actuator to a cylindrical shape) can be included in order to introduce either positive or negative curvature (or no curvature) to the beam wavefront, thereby simplifying the mechatronics of the bender. |
