Lithographic apparatus and device manufacturing method
First Claim
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1. A lithographic apparatus comprising:
- an illumination system to condition a projection beam of radiation;
a support structure to support a patterning device, the patterning device constructed to impart the projection beam with a pattern in its cross-section;
a substrate table to hold a substrate; and
a projection system to project the patterned beam onto a target portion of the substrate;
wherein the patterning device has a critical dimension whose value varies with position across the patterning device, the apparatus further comprising a controller, configured and arranged to vary a radiation dose applied to the target portion according to a position on the target portion so as to compensate for the variation of CD across the patterning device.
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Abstract
A lithographic apparatus comprises an illumination system for providing a projection beam of radiation and a support structure for supporting a patterning device which impart the projection beam with a pattern in its cross-section. The patterning device has a non-flat critical dimension (CD) profile across its width. A projection system projects the patterned beam onto a target portion of a substrate. Dose variation device for varying the radiation dose across the width of the target portion compensates for the non-flat CD profile of the patterning device.
9 Citations
22 Claims
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1. A lithographic apparatus comprising:
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an illumination system to condition a projection beam of radiation;
a support structure to support a patterning device, the patterning device constructed to impart the projection beam with a pattern in its cross-section;
a substrate table to hold a substrate; and
a projection system to project the patterned beam onto a target portion of the substrate;
wherein the patterning device has a critical dimension whose value varies with position across the patterning device, the apparatus further comprising a controller, configured and arranged to vary a radiation dose applied to the target portion according to a position on the target portion so as to compensate for the variation of CD across the patterning device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device manufacturing method comprising:
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providing a projection beam of radiation using an illumination system;
using a patterning device to impart the projection beam with a pattern in its cross-section, the patterning device having a critical dimension whose value varies with position across the patterning device;
projecting the patterned beam of radiation onto a target portion of a substrate; and
varying a radiation dose applied to the target portion according to the position on the target portion so as to compensate for the variation of critical dimension across the patterning device. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of forming a patterning device for imparting a projection beam with a pattern in its cross section in a lithographic apparatus, comprising:
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providing a mask substrate having a radiation blocking film formed thereon;
depositing a layer of resist on the radiation blocking film, the thickness of the layer of resist being different at the edge of the film to the center;
illuminating the resist with a patterned beam of radiation to impose a pattern thereon;
developing the resist to fix the pattern;
etching the radiation blocking layer in the form of the pattern;
whereby the critical dimension of the pattern etched in the chrome layer is different at the edge of the patterning device from that at the center. - View Dependent Claims (22)
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Specification