Importance

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Abstract

Immersion lithography system and method using a sealed wafer bottom are described. One embodiment is an immersion lithography apparatus including a lens assembly comprising an imaging lens and a wafer stage for retaining a wafer beneath the lens assembly and comprising a seal ring for sealing a gap between a bottom edge of a wafer retained on the wafer stage and the wafer stage. The apparatus further includes a fluid tank for retaining immersion fluid, the fluid tank situated with respect to the wafer stage for enabling full immersion of the wafer retained on the wafer stage in the immersion fluid; a cover disposed over at least a portion of the fluid tank for providing a temperature-controlled, fluid-rich environment within the fluid tank; and at least one directional flow control fluid inlet surrounding the imaging lens for directing immersion fluid toward an edge of the wafer retained on the wafer stage closest to the imaging lens.

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First Claim