Method of verifying photomask data based on models of etch and lithography processes
First Claim
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1. A method of verifying a photomask dataset corresponding to a target-pattern, the method comprising:
- obtaining a target polygon having a plurality of vertices and edges;
approximating the target polygon with bounded curvature to create an etch target curve for a wafer;
defining a set of etch target points on the etch target curve;
using a mathematical model of an etch-process to define a set of photoresist points corresponding to the set of etch target points, the mathematical model comprising a model of sidewall effects of an etchant;
obtaining a photoresist curve from the set of photoresist points; and
storing the photoresist curve on a non-transitory computer readable medium.
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Abstract
A photomask dataset corresponding to a target-pattern is verified by simulating a resist-pattern that will be formed in a resist layer by a lithography process, simulating an etched-pattern that will be etched in a layer by a plasma process wherein said simulation comprises calculating a flux of particles impacting a feature, and determining whether the etched-pattern substantially conforms to the target-pattern.
62 Citations
21 Claims
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1. A method of verifying a photomask dataset corresponding to a target-pattern, the method comprising:
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obtaining a target polygon having a plurality of vertices and edges; approximating the target polygon with bounded curvature to create an etch target curve for a wafer; defining a set of etch target points on the etch target curve; using a mathematical model of an etch-process to define a set of photoresist points corresponding to the set of etch target points, the mathematical model comprising a model of sidewall effects of an etchant; obtaining a photoresist curve from the set of photoresist points; and storing the photoresist curve on a non-transitory computer readable medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of verifying a photomask data set corresponding to a target-pattern, the method comprising the following steps in the given order:
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approximating the target-pattern with bounded curvature to create an etch target curve for a wafer; defining a set of etch target points on the etch target curve; obtaining a photoresist-target from the target-pattern using a mathematical model of the etch-process to define a set of photoresist points corresponding to the set of etch target points and obtaining the photoresist-target from the set of photoresist points; calculating a lithographic image intensity at a point on the photoresist-target; determining if the image intensity is in an acceptable range of values; and storing the photoresist-target on a non-transitory computer readable medium. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification