摘要 |
An immersion lithography apparatus has a reticle stage arranged to retain a reticle, a working stage arranged to retain a workpiece, and an optical system including an illumination source and an optical element opposite the workpiece for having an image pattern of the reticle projected by radiation from the illumination source. A gap is defined between the optical element and the workpiece, and a fluid-supplying device serves to supply an immersion liquid into this gap such that the supplied immersion liquid contacts both the optical element and the workpiece during an immersion lithography process. A cleaning device is incorporated for removing absorbed liquid from the optical element during a cleanup process. The cleaning device may make use of a cleaning liquid having affinity to the absorbed liquid, heat, a vacuum condition, ultrasonic vibrations or cavitating bubbles for the removal of the absorbed liquid. The cleaning liquid may be supplied through the same fluid-applying device provided with a switching device such as a valve.
|