| 摘要 |
PROBLEM TO BE SOLVED: To obtain the information of an intensity distribution in a pupil plane without disrupting the operability of a lithographic apparatus and to adjust the configuration of an illumination system at any time for controlling a desired intensity distribution in the pupil plane dependent on measured information about the intensity distribution. SOLUTION: A beam splitter is permanently located in a beam near the pupil plane. The beam splitter splits off an auxiliary beam, which is used to measure information about the spacial intensity distribution of the beam at the pupil plane. Preferably, the measured position dependence in the auxiliary beam may be deconvoluted using boundary conditions inherent to the illuminator to compensate for offset between the pupil plane and a detection element. The measured position dependence may be used to control parameters of an optical element that manipulates the position dependence in the pupil plane. An example of such an optical element is a matrix of elements that controllably steer the direction of parts of the beam. Thus a continuous feedback loop may be realized. COPYRIGHT: (C)2005,JPO&NCIPI
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