NOVELTY - A lithographic apparatus comprises: a radiation source configured to produce a radiation beam; a support configured to support a patterning device; a chamber located between the radiation source and the support; a membrane that defines part of the chamber; and a particle trapping structure configured to permit gas to flow along an indirect path from inside the chamber to outside the chamber.
USE - The lithographic apparatus is useful in lithographic method (claimed).
ADVANTAGE - The lithographic apparatus can capture both fast and slow moving contamination particles such that they are less likely to contaminate the patterning device.
DETAILED DESCRIPTION - A lithographic apparatus comprises: a radiation source configured to produce a radiation beam; a support configured to support a patterning device, the patterning device being configured to impart the radiation beam with a pattern to form a patterned radiation beam; a chamber located between the radiation source and the support, the chamber containing at least one optical component configured to reflect the radiation beam, the chamber being configured to permit radiation from the radiation source to pass through it; a membrane that defines part of the chamber, the membrane configured to permit the passage of the radiation beam through the membrane, and to prevent the passage of contamination particles through the membrane; and a particle trapping structure configured to permit gas to flow along an indirect path from inside the chamber to outside the chamber, the indirect path of the particle trapping structure being configured to substantially prevent the passage of contamination particles from inside the chamber to outside the chamber. INDEPENDENT CLAIMS are:
(1) a lithographic method comprising: generating a radiation beam; directing the radiation beam through a chamber containing at least one optical component that reflects the radiation beam, the radiation beam being directed towards a patterning device, the chamber including a membrane; preventing the passage of contamination particles with the membrane when the radiation beam passes from the chamber through the membrane and towards the patterning device; flowing gas from inside the chamber to outside the chamber along an indirect path through a particle trapping structure, the indirect path substantially preventing the passage of contamination particles from inside the chamber to outside the chamber; imparting the radiation beam with a pattern to form a patterned radiation beam with the patterning device; and projecting the patterned beam of radiation onto a substrate with a projection system;
(2) a spectral purity filter comprising a grid configured to prevent or reduce the passage of infrared radiation, where the grid is covered with graphene which prevents the passage of oxygen to the grid; and
(3) a multi-layer mirror comprising alternating layers of a first material and a second material, where graphene is provided between the alternating layers.
DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a membrane and particle trapping structure.
Gas conduit (32)
Respective openings (40, 42)
Gas flow paths (46)
Outside (48)
Particle trapping structure (52)
Contamination particles (54, 58)
