METHODS AND DEVICES FOR CHARACTERIZING POLARIZATION OF ILLUMINATION SYSTEM

摘要

In a method for evaluating the polarization state of an illumination system (52) in an optical system (50), a mask (56) is provided in the optical system (50) such that an illumination beam incident on the mask (56) is adapted such as to substantially differently diffract incident components of a light beam having different polarization states. An image of the mask (56) is then obtained, using an illumination beam of the illumination system (52) of the optical system (50). The obtained image, being either an intensity plot or a structure created in a resist layer by exposing the resist layer with the image of the mask (56), is then used to extract polarization related information about the illumination system (52). The image used for evaluating may be a diffraction image of the mask.