a liquid immersion scanning exposure system utilizes an immersion liquid confined within a watertight lens hood having a base portion formed from a solid optical element . during operation , a bottom portion of a lens assembly is disposed within the immersion liquid and the solid optical element is placed upon a photoresist material or layer . the lens assembly moves laterally through the immersion liquid parallel to the photoresist material . because the solid optical element separates the immersion liquid from the photoresist material and does not move relative to the photoresist material , the photoresist material does not contact with the immersion liquid and the solid optical element and is not susceptible to damage or scratching by the solid optical element .