LITHOGRAPHIC APPARATUS AND METHODS FOR COMPENSATING SUBSTRATE UNFLATNESS, DETERMINING THE EFFECT OF PATTERNING DEVICE UNFLATNESS, AND DETERMINING THE EFFECT OF THERMAL LOADS ON A PATTERNING DEVICE
First Claim
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1. A lithographic apparatus comprising:
- an illumination system configured to condition a radiation beam;
a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;
a substrate table constructed to hold a substrate;
a projection system configured to project the patterned radiation beam onto a target portion of the substrate; and
a sensor configured to measure a height level, or a curvature, or an angle, or any combination of the foregoing, of a surface of the patterning device supported on the support.
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Abstract
A lithographic apparatus includes an illumination system configured to condition a radiation beam; a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate, and a sensor configured to measure a height level, curvature and/or angle of a surface of a patterning device supported on the support.
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Citations
17 Claims
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1. A lithographic apparatus comprising:
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an illumination system configured to condition a radiation beam; a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate; and a sensor configured to measure a height level, or a curvature, or an angle, or any combination of the foregoing, of a surface of the patterning device supported on the support. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for compensating substrate unflatness in a lithographic process, the lithographic process including forming a patterned radiation beam using a patterning device which is configured to impart a radiation beam with a pattern in its cross-section, and projecting the patterned beam of radiation onto the substrate, the method comprising:
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measuring the substrate unflatness; determining a desired curvature for the patterning device to compensate for the substrate unflatness; measuring a curvature of the patterning device; comparing the measured curvature and the desired curvature; and controlling a patterning device bender configured to bend the patterning device based on the comparing to compensate the substrate unflatness.
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13. A method for determining the effect of patterning device unflatness in a lithographic process, the lithographic process including forming a patterned radiation beam using a patterning device which is configured to impart a radiation beam with a pattern in its cross-section, and projecting the patterned beam of radiation onto the substrate, the method comprising:
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measuring a patterning device unflatness during the lithographic process; determining an imaging error in the lithographic process; and analyzing a relationship between the imaging error and the patterning device unflatness. - View Dependent Claims (14)
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15. A method for determining the effect of thermal loads on a patterning device during a lithographic process, the lithographic process including forming a patterned radiation beam using a patterning device which is configured to impart a radiation beam with a pattern in its cross-section, and projecting the patterned beam of radiation onto the substrate, the method comprising:
measuring a patterning device unflatness during the lithographic process; and
determining a change of the patterning device unflatness in the course of time.- View Dependent Claims (16)
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17. A lithographic apparatus comprising:
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an illumination system configured to condition a radiation beam; a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate; a sensor configured to measure a surface characteristic of the patterning device supported on the support; and a bender configured to bend the patterning device based on the surface characteristic measured by the sensor.
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Specification