Substrate placement in immersion lithography
AssigneeASML Netherlands B.V.
InventorsChristiaan Alexander Hoogendam, Gerrit Johannes Nijmeijer, Minne Cuperus, Petrus Anton Willem Cornelia Maria Van Eijck
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Abstract
A method for determining an offset between a center of a substrate and a center of a depression in a chuck includes providing a test substrate to the depression, the test substrate having a dimension smaller than a dimension of the depression, measuring a position of an alignment mark of the test substrate while in the depression, and determining the offset between the center of the substrate and the center of the depression from the position of the alignment mark.
Claims18
A method for determining an offset between a center of a substrate and a center of a depression in a chuck, comprising:
- measuring a gap between an edge of the substrate disposed inside the depression and an edge of the depression at a plurality of locations;
- determining a center of the substrate using the measurements of the gap;
- determining a chuck centering offset of the substrate between the center of the depression and the measured center of the substrate at the chuck;
- providing the substrate to a prealigner and determining a center of the substrate at the prealigner;
- determining a prealigner centering offset between a nominal center of the substrate and the measured center of the substrate at the prealigner;
- and
- combining the chuck centering offset and the prealigner centering offset to obtain a global centering offset.
A lithographic projection apparatus comprising:
- a support structure configured to hold a patterning device, the patterning device configured to pattern a beam of radiation according to a desired pattern;
- a substrate table configured to hold a substrate, the substrate table having a depression configured to receive the substrate;
- a projection system configured to project the patterned beam onto a target portion of the substrate;
- a liquid supply system configured to provide a liquid, through which the patterned beam is to be projected, in a space between the projection system and the substrate;
- a sensor configured to measure a position of the substrate and to measure a gap between an edge of the substrate disposed inside the depression and an edge of the depression;
- and
- a substrate handling system in communication with the sensor configured to position the substrate inside the depression such that the gap between the edge of the substrate and the edge of the depression is substantially uniform inside the depression.
Dependencies are inferred from the claim text.