Patent Number: 6,253,464

Title: Method for protection of lithographic components from particle contamination

Abstract: A system that employs thermophoresis to protect lithographic surfaces from particle deposition and operates in an environment where the pressure is substantially constant and can be sub-atmospheric. The system (thermophoretic pellicle) comprises an enclosure that surrounds a lithographic component whose surface is being protected from particle deposition. The enclosure is provided with means for introducing a flow of gas into the chamber and at least one aperture that provides for access to the lithographic surface for the entry and exit of a beam of radiation, for example, and further controls gas flow into a surrounding low pressure environment such that a higher pressure is maintained within the enclosure and over the surface being protected. The lithographic component can be heated or, alternatively the walls of the enclosure can be cooled to establish a temperature gradient between the surface of the lithographic component and the walls of the enclosure, thereby enabling the thermophoretic force that resists particle deposition.

Inventors: Klebanoff; Leonard E. (San Ramon, CA), Rader; Daniel J. (Lafayette, CA)

Assignee: Euv LLC

International Classification: G03F 7/20 (20060101); F26B 005/04 ()

Expiration Date: 07/03/2018