lithographic apparatus, a projection system and a device manufacturing method

Abstract

A lithographic apparatus is disclosed that includes a projection system configured to project a patterned radiation beam onto a target portion of a substrate, a vacuum chamber through which the patterned beam of radiation is projected during use, and a purge system configured to provide a purge gas flow in the chamber.

1 . A lithographic apparatus comprising:
 an illumination system configured to condition a radiation beam;   a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;   a substrate table constructed to hold a substrate;   a projection system configured to project the patterned radiation beam onto a target portion of the substrate;   a vacuum chamber through which the patterned beam of radiation is projected during use; and   a purge system configured to provide a purge gas flow in the chamber.   
     
     
         2 . A projection system configured to project a patterned radiation beam onto a target portion of a substrate in a lithographic apparatus, wherein the projection system comprises a vacuum chamber wherein the patterned beam of radiation is projected during use and wherein the projection system further comprises a purge system configured to provide a purge gas flow in the chamber. 
     
     
         3 . The projection system of  claim 2 , wherein the purge system comprises a purge inlet configured to supply a purge gas flow into the vacuum chamber. 
     
     
         4 . The projection system of  claim 3 , wherein the purge inlet is arranged near a region that is critical for contamination particles. 
     
     
         5 . The projection system of  claim 2  wherein the purge system further comprises a pump configured to receive the purge gas flow. 
     
     
         6 . The projection system of  claim 5 , wherein the pump is near a contamination particle source. 
     
     
         7 . A device manufacturing method comprising projecting a patterned beam of radiation onto a substrate, wherein a purge gas flow is applied in a vacuum chamber through which the patterned beam of radiation is projected. 
     
     
         8 . The method of  claim 7 , comprising further providing a purge gas flow path along but outside the patterned beam of radiation and directed away from the patterned beam of radiation. 
     
     
         9 . The method of  claim 7 , comprising further providing a purge gas flow path from a section in a region of the chamber that is traversed by the patterned beam of radiation, towards the outside of the patterned beam of radiation. 
     
     
         10 . The method of  claim 7 , comprising applying a hydrogen purge gas flow. 
     
     
         11 . The method of  claim 10 , comprising applying the hydrogen purge gas flow in a region of the chamber that is traversed by the patterned beam of radiation. 
     
     
         12 . The method of  claim 7 , comprising applying a halogen purge gas flow in a region of the chamber outside the patterned beam of radiation. 
     
     
         13 . The method of  claim 7 , further comprising providing a purge gas flow along a surface of an optical device. 
     
     
         14 . The method of  claim 13 , wherein the temperature of the purge gas flow provided along the surface of the optical device is colder than the temperature of the surface of the optical device.