| 摘要 |
A method of increasing a depth of focus of a lithographic apparatus is disclosed. The method includes forming diffracted beams of radiation using a patterning device pattern; and transforming a phase-wavefront of a portion of the diffracted beams into a first phase-wavefront having a first focal plane for the lithographic apparatus, and a second phase-wavefront having a second, different focal plane, wherein the transforming comprises: subjecting a phase of a first portion of a first diffracted beam and a phase of a corresponding first portion of a second diffracted beam to a phase change which results in an at least partial formation of the first phase-wavefront, and subjecting a phase of a second portion of the first diffracted beam and a phase of a corresponding second portion of the second diffracted beam to a phase change which results in an at least partial formation of the second phase-wavefront. |
