Patent ID: 6924896

Claim:
A method for using a lithography tool including an exposure apparatus and first and second stages, wherein the first and second stages are transposable between an exposure position proximate to the exposure apparatus and another position remote from the exposure position, the method comprising: exposing a first wafer on a first stage to radiation from the exposure apparatus while the first stage is in the exposure position; interferometrically monitoring the location of the first wafer with respect to a reference position for the first wafer during the exposure, wherein the monitoring comprises compensating a measured interference phase based on a first predetermined representation indicative of systematic errors of the interferometry system for the first stage in the exposure position; exchanging the first stage with the second stage at the exposure position; exposing a second wafer on the second stage to radiation from the exposure apparatus while the second stage is in the exposure position; and interferometrically monitoring the location of the second wafer with respect to a reference position for the second wafer during the exposure, wherein the monitoring comprises compensating a measured interference phase based on a second predetermined representation indicative of systematic errors of the interferometry system for the second stage in the exposure position.