Method and exposure apparatus for performing a tilted focus and a device manufactured accordingly

摘要

A method for performing a tilted focus test includes the steps of providing a target object, providing a projection beam of radiation using a radiation source, providing a reflective device to introduce a projected projection beam of radiation onto the target portion, introducing a first projected projection beam of radiation onto the target object using the reflective device in a first orientation, using a tilting device for tilting the reflective device to a second orientation to provide a second projection beam with a tilt relative to said first projection beam, introducing a second projected projection beam of radiation onto the target object, and 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.