Reticle cooling by non-uniform gas flow.

摘要

An apparatus, system, and method cool a patterning device by supplying a non- uniform gas flow. The apparatus and system include a gas supply structure that supplies a gas flow across the first surface of the patterning device. The gas supply structure includes a gas supply nozzle specially configured to create a non-uniform gas flow distribution. A greater 5 volume or velocity of the gas flow is directed to desired portion of the patterning device.