Device manufacturing method, lithographic apparatus and a computer program
AssigneeASML Netherlands B.V.
InventorsAlex Oudshoorn, Leon Martin Levasier, Erik Roelof Loopstra, Roland Blok
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Abstract
The invention relates to a device manufacturing method comprising exposing a substrate with a patterned beam of radiation formed by a reticle mounted on a displaceable reticle stage, wherein the method comprises the steps of determining a non-linear function for approximating a height and a tilt profile of a reticle surface with respect to the reticle stage and controlling a displacement of the reticle stage during exposure of the substrate in accordance with the non-linear function. The invention further relates to a lithographic apparatus and a computer program.
Claims15
A device manufacturing method comprising exposing a substrate with a patterned beam of radiation formed by a reticle having a patterned reticle surface and mounted on a displaceable reticle stage, wherein the method comprises:
- measuring at least a portion of a reticle surface and at least a portion of a reticle stage surface using interferometry;
- determining a non-linear function based only on the measuring of at least a portion of the reticle surface and at least a portion of the reticle stage for approximating a height and a tilt profile of the reticle surface with respect to the reticle stage;
- and
- controlling a displacement of the reticle stage during exposure of the substrate in accordance with the non-linear function.
A lithographic apparatus arranged to project a pattern from a patterning device onto a substrate, said apparatus comprising:
- a displaceable reticle stage configured to support a reticle, said reticle having a patterned reticle surface;
- one or more interferometric detectors configured to determine data from surface measurement of at least a portion of a reticle surface and at least a portion of a reticle stage surface;
- a processor configured to approximate a height and a tilt profile of the reticle surface with respect to the reticle stage by a non-linear function using only the data from the surface measurement of at least a portion of the reticle surface and at least a portion of the reticle stage surface;
- and
- a controller configured to control a displacement of the reticle stage during exposure of the substrate in accordance with the non-linear function.
A lithographic apparatus comprising:
- an illumination system configured to condition a radiation beam;
- a reticle stage configured to support a reticle having a patterned reticle surface, the reticle being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam, whereby the reticle stage is displaceably arranged;
- a substrate table configured to hold a substrate;
- a projection system configured to project the patterned radiation beam onto a target portion of the substrate;
- one or more interferometric detectors configured to determine data from surface measurement of at least a portion of a reticle surface and at least a portion of a reticle stage surface;
- a processor configured to approximate a height and a tilt profile of the reticle surface by a non-linear function using only the data from the surface measurement of at least a portion of the reticle surface and at least a portion of the reticle stage surface;
- and
- a controller for controlling a displacement of the reticle stage during exposure of the substrate in accordance with the non-linear function.
Dependencies are inferred from the claim text.