摘要 |
A lithographic apparatus includes an illumination system configured to condition a radiation beam and a support constructed to support a patterning device. The patterning device is configured to form a patterned radiation beam. A substrate table is constructed to hold a substrate, and a projection system is configured to project the patterned radiation beam onto a target portion of the substrate. The apparatus includes a heater arrangement that includes an electron beam generator configured to generate an electron beam, and an electron beam guide arrangement configured to guide the electron beam onto an optical element of the lithographic apparatus. The optical element forms a part of the illumination system or the projection system which, in use, is traversed by the radiation beam. The heater arrangement is controllable to provide a distribution of heat on the optical element by deflection of the electron beam. |