| 摘要 |
The invention is directed to a method for performing a tilted focus test that includes providing a target object, providing a projection beam of radiation using a radiation source, providing at least one reflective device to produce a projected projection beam of radiation onto the target portion, and producing a first projected projection beam of radiation onto the target object using the at least one reflective device in a first orientation. The invention further includes using a tilting device for tilting the at least one reflective device to a second orientation to provide a second projection beam with a tilt relative to said first projection beam, producing a second projected projection beam of radiation onto the target object, determining a lateral shift of the first and second projected projection beams on the target object, and determining from said lateral shift a defocus of the target object with respect to the projected projection beam.
|
