ASML Holding N.V.
Method and apparatus for determining alignment properties of a beam of radiation

Abstract:

A method of and an apparatus for use in determining one or more alignment properties of an illumination beam of radiation emitted by a radiation source are provided. The illumination beam is for irradiating a target area on a substrate in a metrology apparatus. The method comprises: (a) obtaining a first set of intensity data; (b) obtaining a second set of intensity data; (c) processing said first and second sets of intensity data to determine said one or more alignment properties of said illumination beam of radiation; wherein said processing involves comparing said first and second sets of intensity data to calculate a value which is indicative of a translation of said illumination beam of radiation.