MEASUREMENT OF THE POSITION OF A RADIATION BEAM SPOT IN LITHOGRAPHY

摘要

A radiation spot measurement system for a lithographic apparatus, the system having a target onto which a radiation system of the lithographic apparatus may project spots of radiation for a measurement process, the target having a measurement target. The system further includes a radiation detector to detect radiation from one of the spots, and a controller to receive information from the radiation detector and to determine the position of the spot of radiation relative to an intended position of the spot of radiation.