Patent ID: 8330935
Filing Date: 2012-12-11
Classification: G03F

Abstract:
1. An optical system, comprising: an illumination system configured to generate projection light; a projection lens configured to image a mask onto a photosensitive layer, an immersion space being between the projection lens and the photosensitive layer; an immersion liquid in the immersion space, the immersion liquid being in direct contact with the projection lens and the photosensitive layer to define an interface between the immersion liquid and a surrounding gas, the interface extending between the projection lens and the photosensitive layer; a heat transfer element configured so that, during an immersion operation, the heat transfer element transfers an amount of heat to or from the immersion liquid: a) at the interface between the immersion liquid and a surrounding gas; or b) within the immersion liquid; and a control device configured to adjust the amount of heat transferred by the heat transfer element to or from the immersion liquid, wherein the optical system is a microlithographic projection exposure apparatus.