Method for exposing a substrate, patterning device, and lithographic apparatus

摘要

A method using a lithographic apparatus comprising a reflective integrator is claimed that optimizes the exposure of features on a target area of a substrate, when the features make an angle between 5 and 85 degrees with respect to the target area. The method comprises rotating the reflective integrator with respect to the target area providing a rotated mirror-symmetric pupil shape, which is implemented by either rotating the substrate or rotating the reflective integrator with respect to the machine or the patterning device. The patterning device comprises a maximum usable area and a patterned area which are rotated with respect to each other if a rotated substrate is employed. The method can be used in single exposure or double exposure mode. A further advantage of the method of using a rotated wafer is that it can be used for exposing features on a substrate in any direction even when the projection system of the lithographic apparatus shows a preferred polarization direction.