Dedicated metrology stage for lithography applications

A lithography system, comprising:

• an illumination system that produces a beam of radiation;
• a patterning device that patterns the beam;
• a projection system that projects the patterned beam onto a substrate;
• a substrate stage that is configured to position the substrate to receive the patterned beam;
• and
• a metrology stage having a sensor system thereon that is configured to detected parameters of the projection system or the patterned beam, wherein the sensor system comprises a stray light sensor, a slit uniformity sensor, a relative polarization sensor, an apodization sensor, an absolute polarization sensor, an image quality sensor, or a wavefront aberration sensor.

A method of measuring optical parameters of an exposure portion of a lithography system, the method comprising:

• moving a substrate stage away from an optical axis of the exposure portion;
• moving a metrology stage to locate a sensor in the optical axis;
• and
• measuring an optical parameter of light from the exposure system, the optical parameter comprising stray light, apodization, slit uniformity, relative polarization, absolute polarization sensor, image quality, or wavefront aberration.