Lithographic apparatus, device manufacturing method and device manufacturing thereby
First Claim
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1. A lithographic projection apparatus comprising:
- a support structure configured to support a patterning device, the patterning device serving to pattern a beam of radiation according to a desired pattern;
a substrate table configured to hold a substrate;
a projection system configured to project the patterned beam onto a target portion of the substrate; and
a displacement measuring system configured to measure the position of a moveable object in at least two degrees of freedom, the moveable object comprising said support structure or said substrate table, said displacement measuring system comprising at least one grid grating mounted on said moveable object and at least one sensor head configured to measure displacements of said grid grating in two degrees of freedom,wherein the at least one grid grating includes a reference mark detectable by the respective sensor head for defining a reference position of the moveable object.
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Abstract
The X, Y and Rx positions of a mask stage are measured using two optical encoder-reading heads measuring displacements of respective grid gratings mounted on the mask stage. The grid gratings are preferably provided on cut-away portions of the mask table so as to be coplanar with the pattern on the mask itself. Measurements of the table position in the other degrees of freedom can be measured with capacitative or optical height sensors.
188 Citations
27 Claims
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1. A lithographic projection apparatus comprising:
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a support structure configured to support a patterning device, the patterning device serving to pattern a beam of radiation according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; and a displacement measuring system configured to measure the position of a moveable object in at least two degrees of freedom, the moveable object comprising said support structure or said substrate table, said displacement measuring system comprising at least one grid grating mounted on said moveable object and at least one sensor head configured to measure displacements of said grid grating in two degrees of freedom, wherein the at least one grid grating includes a reference mark detectable by the respective sensor head for defining a reference position of the moveable object. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A lithographic projection apparatus, comprising:
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a support structure configured to support a patterning device, the patterning device serving to pattern a beam of radiation according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; and a displacement measuring system configured to measure the position of a moveable object in at least two degrees of freedom, the moveable object comprising said support structure or said substrate table, said displacement measuring system comprising two grid gratings mounted on said moveable object at spaced apart locations and two sensor heads each configured to measure displacements of a respective one of said grid gratings in two degrees of freedom.
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9. A lithographic projection apparatus comprising:
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a support structure configured to support a patterning device, the patterning device serving to pattern a beam of radiation according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; and a displacement measuring system configured to measure the position of a moveable object comprising one of said support structure and said substrate table in at least two degrees of freedom, said displacement measuring system comprising at least one grid grating mounted on a reference frame and at least one sensor head mounted on said moveable object configured to measure displacement of said moveable object relative to said grid grating in two degrees of freedom. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A lithographic projection apparatus comprising:
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a support structure configured to support a patterning device, the patterning device serving to pattern a beam of radiation according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; and a displacement measuring system configured to measure the position of a moveable object in at least two degrees of freedom, the moveable object comprising said support structure or said substrate table, said displacement measuring system comprising at least one grid grating mounted on said moveable object and at least one sensor head configured to measure displacements of said grid grating in two degrees of freedom, wherein said moveable object is moveable in a first direction for scan imaging and said grid grating has a length in said first direction greater than or equal to the range of motion of said moveable object in said first direction.
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24. A lithographic projection apparatus comprising:
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a support structure configured to support a patterning device, the patterning device serving to pattern a beam of radiation according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; and a displacement measuring system configured to measure the position of a moveable object in at least two degrees of freedom, the moveable object comprising said support structure or said substrate table, said displacement measuring system comprising at least one grid grating mounted on said moveable object and at least one sensor head configured to measure displacements of said grid grating in two degrees of freedom, wherein the grid grating is positioned so as to be substantially coplanar with the functional surface of said patterning device supported by said support structure or a substrate held by said substrate table.
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25. A device manufacturing method comprising:
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projecting a patterned beam of radiation onto a target portion of a layer of radiation-sensitive material on a substrate; measuring displacements of one of a support structure for a patterning device for patterning the beam of radiation and a substrate table for holding the substrate, in at least two degrees of freedom using at least one grid grating mounted thereon and at least one sensor head, wherein the at least one grid grating includes a reference mark detectable by the respective sensor head for defining a reference position of said moveable object; and supplying or making available the measured displacements for further analysis or processing. - View Dependent Claims (26, 27)
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Specification