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AssigneeNumerical Technologies, Inc.
InventorHua-yu Liu
Estimating the term…
By using a test pattern that has been corrected according to an optical model to prepare test wafers, better data can be obtained for calibrating the optical model. As a result: fewer measurements need to be taken from the wafer to calibrate the model and the measurements that are taken are more valuable because they better assist in calibrating the model. Embodiments of the invention include data comprising the corrected test pattern, masks including the corrected test pattern, and methods and apparatuses for using the modified test pattern. Additionally, by taking more measurements closer to the target dimensions, more information is available for performing optical proximity correction of layouts. Another benefit includes increased ease of model accuracy determinations.
A method for using a test pattern to calibrate an optical model related to a manufacturing process for an integrated circuit, comprising:
A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for using a test pattern to calibrate an optical model related to a manufacturing process for an integrated circuit, the method comprising:
An apparatus, for using a test pattern to calibrate an optical model related to a manufacturing process for an integrated circuit, comprising:
A system for using a test pattern to calibrate an optical model related to a manufacturing process for an integrated circuit, comprising:
An optical proximity corrected test mask used for calibrating an optical model, comprising a plurality of lines within the optical proximity corrected test mask, wherein the plurality of lines have been partially corrected by an optical proximity correction process to compensate for optical effects.
A data set related to an optical proximity corrected test pattern used for calibrating an optical model, comprising:
An electromagnetic waveform encoding instructions that when executed by a computer cause the computer to perform a method for using a test pattern to calibrate an optical model related to a manufacturing process for an integrated circuit, the method comprising:
Dependencies are inferred from the claim text.
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Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring…:…
Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof: testing or measuring features, e.g.…
Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles…
Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating…
Term end not estimated
1. Field of the Invention
The invention relates to the process of manufacturing an integrated circuit. More specifically, the invention relates to a method and an apparatus for calibrating a model related to manufacturing the integrated circuit.
2. Related Art
FIG. 1A illustrates line width and pitch.
FIG. 1B is a flowchart illustrating the process of calibrating a model.
FIG. 1C is a graph plotting actual line width versus pitch for a target line width.
Creating Model Calibrations
FIG. 2A is a flowchart illustrating the process of calibrating an optical model in accordance with an embodiment of the invention. An optical model is a model created by a model generator such as ModelGen™, which corrects for optical effects while creating an integrated circuit. These effects include numerical aperture (NA), wavelength (λ), and sigma (σ). Calibrating this model with a model calibrator such as ModelCal™ allows the calibrated model to compensate for resist and/or etch effects. ModelGen™ and ModelCal™ are trademarks or registered trademarks of Numerical Technologies, Inc. of San Jose, Calif. The system starts when a basic test pattern containing multiple line widths and pitches is received (step 202). Next, the system performs optical proximity correction on the test pattern (step 204). Note that performing optical proximity correction on the test pattern at this stage provides more accurate results on the wafer line widths and, therefore, provides better data for model calibration. A mask is then created from the test pattern (step 206). After creating the mask, a test wafer is formed using the mask (step 208).
After the test wafer has been fabricated, the actual line widths and pitches are measured (step 210). Next, the actual line widths are compared with the desired line widths to determine the error in the actual line widths (step 212). Finally, the model is calibrated for resist and/or etch effects so that the model will create line widths closer to the desired line widths (step 214). Since optical proximity correction has been performed on the test pattern, the corrections are more accurate and determined with fewer measurements and calculations.