System and method for creating a focus-exposure model of a lithography process

Claim 1

A computer-implemented method for creating a focus-exposure model of a lithography process, comprising: selecting a set of process conditions within a predetermined process window of a lithography process, the set of process conditions being a subset of all possible process conditions within the process window, each process condition being an exposure value and a defocus value; selecting a model of the lithography process, the model including an optical model module, the model having a set of model parameters including focus, exposure, and a set of fitting parameters having variable values; simulating, using the computer, the lithography process at each of the set of process conditions using the model to produce simulated results, wherein values of the focus and exposure parameters are varied to correspond to the set of process conditions and the fitting parameter values are held constant; and calibrating, using the computer, the model by comparing the simulated results with actual results of the lithography process at all of the set of process conditions to produce a single focus-exposure model capable of simulating the lithography process at all possible process conditions within the predetermined process window.

Claim 25

A system for generating a single process window model for predicting the capability of a lithography process, comprising: a storage area for storing information; an input device; an output device; physical model information stored in the storage area; and a model calibration module; the storage area being in communication with the model calibration module such that selected physical model information can be accessed by the model calibration module; the input device being in communication with the model calibration module such that process window definition information defining a process window can be made available to the model calibration module and such that discrete measurement information obtained from measurements of a wafer under different test conditions in the defined process window can be accessed by the model calibration module, and the model calibration module is configured to generate a single process window model by using the process window definition information and the discrete measurement information to calibrate the selected physical model information such that the performance of a lithography process over the defined process window can be described with two continuously adjustable optical parameters, wherein generating the single process window model includes comparing the discrete measurement information with simulated measurements, the simulated measurements produced by simulating the lithography process using the selected physical model information by varying the two continuously adjustable optical parameters while holding all other parameters in the physical model information constant.

Claim 26

A system for generating a single process window model for predicting the capability of a lithography process, comprising: a storage area for storing information; an input device; an output device; physical model information stored in the storage area; and a model calibration module; the storage area being in communication with the model calibration module such that selected physical model information can be accessed by the model calibration module; the input device being in communication with the model calibration module such that process window definition information defining a process window can be made available to the model calibration module and such that discrete measurement information obtained from measurements of a wafer under different test conditions in the defined process window can be accessed by the model calibration module, and the model calibration module is configured to generate a single process window model by using the process window definition information and the discrete measurement information to calibrate the selected physical model information such that the performance of a lithography process over the defined process window can be described with two continuously adjustable optical parameters, wherein generating the single process window model includes comparing the discrete measurement information with simulated measurements, the simulated measurements produced by simulating the lithography process using the selected physical model information by varying the two continuously adjustable optical parameters while holding all other parameters in the physical model information constant.