Method and apparatus for determining an improved assist feature configuration in a mask layout
First Claim
1. A method for determining an assist feature configuration which specifies locations and dimensions for one or more assist features in a mask layout, the method comprising:
- receiving the mask layout;
creating a set of candidate assist feature configurations;
selecting a set of evaluation points in the mask layout;
determining process-variation values at the set of evaluation points for the set of candidate assist feature configurations, wherein convolving the mask layout with the process-sensitivity model at an evaluation point in the mask layout generates a value that is indicative of the mask layout'"'"'s sensitivity to process variations at the evaluation point,wherein determining the process-variation values includes;
placing representative assist features in the mask layout based on a candidate assist feature configuration in the set of candidate assist feature configurations;
evaluating process-variation values at the set of evaluation points by convolving the process-sensitivity model with the mask layout; and
determining an improved assist feature configuration using the process-variation values,wherein determining the improved assist feature configuration using the process-variation values includes;
formulating an optimization problem based on the process-variation values, wherein a solution to the optimization problem is associated with an assist feature configuration;
computing a substantially optimal solution to the optimization problem; and
determining the improved assist feature configuration based on the substantially optimal solution to the optimization problem;
wherein placing assist features in the mask layout based on the improved assist feature configuration improves the mask layout'"'"'s manufacturability;
wherein using the process-sensitivity model to determine the improved assist feature configuration reduces an amount of computational time required to determine the improved assist feature configuration.
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Abstract
One embodiment of the present invention provides a system that determines the locations and dimensions of one or more assist features in an uncorrected or corrected mask layout. During operation, the system receives a mask layout. The system then creates a set of candidate assist feature configurations, which specify locations and sizes for one or more assist features in the mask layout. Next, the system determines an improved assist feature configuration using the set of candidate assist feature configurations and a process-sensitivity model which can be represented by a multidimensional function that captures process-sensitivity information. Note that placing assist features in the mask layout based on the improved assist feature configuration improves the manufacturability of the mask layout. Moreover, using the process-sensitivity model to determine the improved assist feature configuration reduces the computational time required to determine the improved assist feature configuration in the mask layout.
57 Citations
12 Claims
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1. A method for determining an assist feature configuration which specifies locations and dimensions for one or more assist features in a mask layout, the method comprising:
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receiving the mask layout; creating a set of candidate assist feature configurations; selecting a set of evaluation points in the mask layout; determining process-variation values at the set of evaluation points for the set of candidate assist feature configurations, wherein convolving the mask layout with the process-sensitivity model at an evaluation point in the mask layout generates a value that is indicative of the mask layout'"'"'s sensitivity to process variations at the evaluation point, wherein determining the process-variation values includes; placing representative assist features in the mask layout based on a candidate assist feature configuration in the set of candidate assist feature configurations; evaluating process-variation values at the set of evaluation points by convolving the process-sensitivity model with the mask layout; and determining an improved assist feature configuration using the process-variation values, wherein determining the improved assist feature configuration using the process-variation values includes; formulating an optimization problem based on the process-variation values, wherein a solution to the optimization problem is associated with an assist feature configuration; computing a substantially optimal solution to the optimization problem; and determining the improved assist feature configuration based on the substantially optimal solution to the optimization problem; wherein placing assist features in the mask layout based on the improved assist feature configuration improves the mask layout'"'"'s manufacturability; wherein using the process-sensitivity model to determine the improved assist feature configuration reduces an amount of computational time required to determine the improved assist feature configuration. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A computer-readable storage device storing instructions that when executed by a computer cause the computer to perform a method for determining an assist feature configuration which specifies locations and dimensions for one or more assist features in a mask layout, the method comprising:
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receiving the mask layout; creating a set of candidate assist feature configurations; selecting a set of evaluation points in the mask layout; determining process-variation values at the set of evaluation points for the set of candidate assist feature configurations, wherein convolving the mask layout with the process-sensitivity model at an evaluation point in the mask layout generates a value that is indicative of the mask layout'"'"'s sensitivity to process variations at the evaluation point, wherein determining the process-variation values includes; placing representative assist features in the mask layout based on a candidate assist feature configuration in the set of candidate assist feature configurations; evaluating process-variation values at the set of evaluation points by convolving the process-sensitivity model with the mask layout; and determining an improved assist feature configuration using the process-variation values, wherein determining the improved assist feature configuration using the process-variation values includes; formulating an optimization problem based on the process-variation values, wherein a solution to the optimization problem is associated with an assist feature configuration; computing a substantially optimal solution to the optimization problem; and determining the improved assist feature configuration based on the substantially optimal solution to the optimization problem; wherein placing assist features in the mask layout based on the improved assist feature configuration improves the mask layout'"'"'s manufacturability; wherein using the process-sensitivity model to determine the improved assist feature configuration reduces an amount of computational time required to determine the improved assist feature configuration. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification