Method of verifying photomask data based on models of etch and lithography processes
AssigneeCadence Design Systems, Inc.
InventorsBayram Yenikaya, Devendra Joshi, Paul A. Fornari, Jesus O. Carrero, Abdurrahman Sezginer
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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.
Claims21
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.
A method of verifying a photomask data set corresponding to a target-pattern, the method comprising the following steps in the given order:
- 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.
Dependencies are inferred from the claim text.