| 摘要 |
A method comprising illuminating a patterning device comprising a plurality of patterned regions which each pattern a measurement beam, projecting, with a projection system, the measurement beams onto a sensor apparatus comprising a plurality of detector regions, making a first measurement of radiation when the patterning device and the sensor apparatus are positioned in a first relative configuration, moving at least one of the patterning device and the sensor apparatus so as to change the relative configuration of the patterning device to a second relative configuration, making a second measurement of radiation when the patterning device and the sensor apparatus are positioned in the second relative configuration in which at least some of the plurality of detector regions receive a different measurement beam to the measurement beam which was received at the respective detector region in the first relative configuration and determining aberrations caused by the projection system. |
