Patent ID: 9128389
Filing Date: 2015-09-08
Classification: G03F

Abstract:
1. A method, comprising: providing a microlithographic projection exposure apparatus, comprising: determining a polarization distribution in a plane of the microlithographic projection exposure apparatus; determining parameter values from the polarization distribution in the plane, wherein a parameter value is a ratio of intensity of light in a polarization state to the total intensity of light at a location in the plane; determining average parameter values, wherein an average parameter value is an average of parameter values at locations along a scanning direction of the microlithographic projection exposure apparatus; determining a difference between a maximum value and a minimum value of the average parameter values, and rotating an element about the optical axis to reduce a local variation of the polarization distribution in the plane to provide a polarization distribution in the plane which is closer to a desired polarization distribution in the plane than is the determined polarization distribution in the plane, wherein: