Patent ID: 6987275
Filing Date: 2006-01-17
Classification: B82Y,G03F,G21K,H05G

Abstract:
1. A lithographic projection apparatus, comprising: a radiation system constructed and arranged to provide a pulsed beam of radiation; a support structure constructed and arranged to support a patterning device, the patterning device constructed and arranged to pattern the pulsed beam according to a desired pattern; a substrate table constructed and arranged to hold a substrate; a projection system constructed and arranged to project the patterned beam onto a target portion of the substrate; and a barrier constructed and arranged to prevent at least one of gas and particle flow from a first part of the apparatus to a second part of the apparatus that is at a lower pressure than said first part, the barrier comprising: a controlled aperture constructed and arranged to permit passage of pulses of the beam of radiation through the barrier when the controlled aperture is open and to substantially prevent one of gas and particle flow from the first to the second part of the apparatus when the controlled aperture is closed; and a controller that operates the controlled aperture to open and close the controlled aperture in synchronism with the pulsed beam.