| 摘要 |
A mask can be used to print a pattern. Due to mask pattern surface topography, an image error may occur, such as an intensity imbalance between adjacent bright lines in the projected pattern. To help alleviate or eliminate the problem of intensity imbalance, the projection system may include an optical phase adjuster constructed and arranged to adjust a phase of an electric field of optical beams of radiation beam traversing the adjuster. A reduction of intensity imbalance is achieved by suitably adjusting the phases of the zeroth, plus first and minus first-order diffracted radiation emanating from the mask pattern. By adjusting the phase differently for different portions of the illumination, the method can be applied such that no decrease of depth of focus due, for example, the 0th order is occurring. |
