Patent ID: 7880863

Claim:
A lithographic system comprising: a light source configured to provide a light beam; a mask stage configured to hold a mask having a mask pattern; a wafer stage having a surface configured to hold a wafer having a plurality of dies, each die having a boundary defining an areal extent; an illumination monitor including: a receiver disposed at the surface of the wafer stage having an areal extent at least equal to the areal extent of the die; and a polarimeter; and a projection system configured to shape and direct the light beam, including via the mask pattern, to form an exposure beam including the mask pattern and with an areal extent equal to the areal extent of the die, configured to individually expose each die with the exposure beam, and configured to shape and direct the light beam to form a monitor beam having are areal extent equal to that of the exposure beam and to expose the receiver with the monitor beam, wherein the receiver is configured to communicate the monitor beam to the polarimeter which, based on the monitor beam, is configured to provide a plurality of illumination signals representative of one or more properties of the light beam as it passes through the lithographic system.