Model-based scanner tuning systems and methods
First Claim
1. A method implemented by a computer, the method being for obtaining a sensitivity model that predicts changes in imaging behavior due to changes in a set of tunable parameters on a corresponding lithographic apparatus, the method comprising:
- maintaining a lithographic process model characterizing imaging behavior of a corresponding lithographic process for a given layer of a wafer using the corresponding lithographic apparatus, given particular values for the set of tunable parameters on the corresponding lithographic apparatus;
generating a simulated wafer contour in the given layer using a design layout and the lithographic process model based on a set of values of the set of tunable parameters;
identifying discrepancies in the simulated wafer contour against a reference corresponding to the set of values of the set of tunable parameters;
quantifying the discrepancies with a cost function; and
performing iterations of the generating and identifying steps to minimize the cost function and obtain calibrated parameters of the sensitivity model, wherein a value of at least one tunable parameter of the corresponding lithographic apparatus is adjusted prior to performing each iteration, and wherein the reference for each iteration is different in accordance with the adjusted value of the at least one tunable parameter,wherein one or more of the maintaining, generating, identifying, quantifying and performing steps are implemented by the computer.
2 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods for tuning photolithographic processes are described. A model of a target scanner is maintained defining sensitivity of the target scanner with reference to a set of tunable parameters. A differential model represents deviations of the target scanner from the reference. The target scanner may be tuned based on the settings of the reference scanner and the differential model. Performance of a family of related scanners may be characterized relative to the performance of a reference scanner. Differential models may include information such as parametric offsets and other differences that may be used to simulate the difference in imaging behavior.
-
Citations
13 Claims
-
1. A method implemented by a computer, the method being for obtaining a sensitivity model that predicts changes in imaging behavior due to changes in a set of tunable parameters on a corresponding lithographic apparatus, the method comprising:
-
maintaining a lithographic process model characterizing imaging behavior of a corresponding lithographic process for a given layer of a wafer using the corresponding lithographic apparatus, given particular values for the set of tunable parameters on the corresponding lithographic apparatus; generating a simulated wafer contour in the given layer using a design layout and the lithographic process model based on a set of values of the set of tunable parameters; identifying discrepancies in the simulated wafer contour against a reference corresponding to the set of values of the set of tunable parameters; quantifying the discrepancies with a cost function; and performing iterations of the generating and identifying steps to minimize the cost function and obtain calibrated parameters of the sensitivity model, wherein a value of at least one tunable parameter of the corresponding lithographic apparatus is adjusted prior to performing each iteration, and wherein the reference for each iteration is different in accordance with the adjusted value of the at least one tunable parameter, wherein one or more of the maintaining, generating, identifying, quantifying and performing steps are implemented by the computer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
Specification