CORRECTION FOR FLARE EFFECTS IN LITHOGRAPHY SYSTEM
First Claim
1. A method for reducing an effect of flare produced by a lithographic system for imaging a design layout onto a substrate, the method comprising:
- simulating a flare map in an exposure field of the lithographic system by mathematically combining a density map of the design layout at the exposure field with a point spread function (PSF), wherein system-specific effects on the flare map are incorporated in the simulation; and
calculating location-dependent flare corrections for the design layout by using the determined flare map, thereby reducing the effect of flare.
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Abstract
A method for reducing an effect of flare produced by a lithographic apparatus for imaging a design layout onto a substrate is described. A flare map in an exposure field of the lithographic apparatus is simulated by mathematically combining a density map of the design layout at the exposure field with a point spread function (PSF), wherein system-specific effects on the flare map may be incorporated in the simulation. Location-dependent flare corrections for the design layout are calculated by using the determined flare map, thereby reducing the effect of flare. Some of the system-specific effects included in the simulation are: a flare effect due to reflection from black border of a mask, a flare effect due to reflection from one or more reticle-masking blades defining an exposure slit, a flare effect due to overscan, a flare effect due reflections from a gas-lock sub-aperture of a dynamic gas lock (DGL) mechanism, and a flare effect due to contribution from neighboring exposure fields.
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Citations
15 Claims
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1. A method for reducing an effect of flare produced by a lithographic system for imaging a design layout onto a substrate, the method comprising:
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simulating a flare map in an exposure field of the lithographic system by mathematically combining a density map of the design layout at the exposure field with a point spread function (PSF), wherein system-specific effects on the flare map are incorporated in the simulation; and calculating location-dependent flare corrections for the design layout by using the determined flare map, thereby reducing the effect of flare. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for reducing an effect of flare produced by a lithographic system for imaging a design layout onto a substrate, the method comprising:
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determining a flare map in an exposure field of the lithographic system by mathematically combining a density map of the design layout at the exposure field with a point spread function (PSF), wherein the density map comprises a representation of the design layout after being modified by optical enhancement features (OEF); and calculating location-dependent flare corrections for the post-OEF design layout by using the determined flare map, thereby reducing the effect of flare.
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Specification