Lithographic apparatus and device manufacturing method
AssigneeASML Netherlands B.V.
InventorsHans Jansen, Patricius Aloysius Jacobus Tinnemans, Jan-Gerard Cornelis Van Der Toorn
Life of this patent
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Abstract
The present invention relates to the method of reducing contamination of an immersion liquid in a lithographic apparatus when a closing surface is used to confine liquid in a liquid supply system. To avoid or reduce particulate contamination caused by the closing surface colliding with the liquid supply system, the closing surface is maintained at a distance away from the liquid supply system such that there is no collision between the closing surface and the liquid supply system, but the liquid is nonetheless confined.
Claims20
A lithographic apparatus, comprising:
- a projection system configured to project a patterned radiation beam onto a substrate supported by a substrate table;
- a liquid supply system configured to supply a space between the projection system and the substrate with a liquid;
- a closing surface configured to provide a confining surface for liquid supplied by the liquid supply system in place of the substrate;
- and
- a closing surface positioning device configured to create and maintain a gap between the liquid supply system and the closing surface when the closing surface is used to confine the liquid supplied by the liquid supply system,
- wherein, in use at a point in time, (i) no portion of the closing surface comes in contact with the liquid supply system, (ii) the closing surface is held only by the liquid supply system, and (iii) liquid flows within the gap.
A device manufacturing method, comprising:
- supplying a liquid to a space between a projection system of a lithographic projection apparatus and a substrate supported by a substrate table using a liquid supply system;
- creating and maintaining a gap between the liquid supply system and a closing surface when the closing surface confines the liquid supplied by the liquid supply system in place of a substrate;
- and
- projecting a patterned beam of radiation through the liquid onto the substrate when the substrate is used as a confining surface for the liquid supplied by the liquid supply system,
- wherein, at a point in time, (i) no portion of the closing surface comes in contact with the liquid supply system, (ii) the closing surface is held only by the liquid supply system, and (iii) liquid flows within the gap.
Dependencies are inferred from the claim text.