Cleanup method for optics in immersion lithography

Abstract

In an immersion lithography apparatus, a projection optics having a final surface projects a pattern image onto a workpiece through a liquid immersion area between the final surface and an upper surface of the workpiece during an immersion lithography process in which the immersion liquid is supplied from above the workpiece via the liquid supply port and the supplied immersion liquid is collected from above the workpiece via the liquid recovery port. During a cleanup process, an object different from the workpiece is placed instead of the workpiece, a cleaning liquid is supplied onto the object from above the object via the liquid supply port, and the supplied cleaning liquid is collected from above the object via the recovery port. The cleaning liquid is not allowed to be used for projecting the pattern image.

What is claimed is: 
     
         1 . An immersion lithography apparatus comprising:
 a liquid supply port;   a liquid recovery port; and   a projection optics having a final surface, the projection optics projecting a pattern image onto a workpiece through a liquid immersion area between the final surface and an upper surface of the workpiece during an immersion lithography process, wherein   during the immersion lithography process, the immersion liquid is supplied from above the workpiece via the liquid supply port and the supplied immersion liquid is collected from above the workpiece via the liquid recovery port, and only a portion of the upper surface of the workpiece is covered with the liquid immersion area in which the supplied immersion liquid is included,   during a cleanup process, an object having a surface, the object being different from the workpiece, is placed instead of the workpiece, a cleaning liquid is supplied onto the object from above the object via the liquid supply port, and the supplied cleaning liquid is collected from above the object via the recovery port, and   the cleaning liquid is not allowed to be used for projecting the pattern image.