Systems and methods for thermally-induced aberration correction in immersion lithography

摘要

Immersion lithography aberration control systems and methods that compensate for a heating effect of exposure energy in an immersion fluid across an exposure zone are provided. An aberration control system includes actuators that adjust optical elements within the immersion lithography system and a fluid heating compensation module coupled to the actuators. The fluid heating adjustment module determines actuator commands to make aberration adjustments to optical elements within the immersion lithography system based on changes in one or more of a flow rate of the immersion liquid, an exposure dose and a reticle pattern image. In an embodiment, the aberration control system includes an interferometric sensor that pre-calibrates aberrations based on changes in operating characteristics related to the immersion fluid. Methods are provided that calibrate aberrations, determine actuator adjustments and implement actuator adjustments upon changes in operating characteristics to control aberration effects.