METHODS AND APPARATUSES FOR ETCH PROFILE OPTIMIZATION BY REFLECTANCE SPECTRA MATCHING AND SURFACE KINETIC MODEL OPTIMIZATION
First Claim
1. A method of optimizing a computer model which relates etch profiles of features on semiconductor substrates to a set of independent input parameters, the method comprising:
- (a) identifying values for one or more model parameters to be optimized;
(b) receiving experimental reflectance spectra generated from optical measurements of one or more semiconductor substrates etched using an experimental etch process performed using values of the set of independent input parameters;
(c) generating computed reflectance spectra from the model using the values for the set of independent input parameters specified in (b); and
(d) modifying the values of the one or more model parameters identified in (a) and repeating (c) with the modified values of the one or more model parameters so as to reduce a metric indicative of the differences between the experimental reflectance spectra received in (b) and corresponding computed reflectance spectra generated in (c) with respect to the values of the set of independent input parameters, thereby producing modified values for the one or more model parameters for use in the computer model which relates etch profiles of features on semiconductor substrates to the set of independent input parameters.
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Abstract
Disclosed are methods of optimizing a computer model which relates the etch profile of a feature on a semiconductor substrate to a set of independent input parameters (A), via the use of a plurality of model parameters (B). In some embodiments, the methods may include modifying one or more values of B so as to reduce a metric indicative of the differences between computed reflectance spectra generated from the model and corresponding experimental reflectance spectra with respect to one or more sets of values of A. In some embodiments, calculating the metric may include an operation of projecting the computed and corresponding experimental reflectance spectra onto a reduced-dimensional subspace and calculating the difference between the reflectance spectra as projected onto the subspace. Also disclosed are etch systems implementing such optimized computer models.
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Citations
25 Claims
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1. A method of optimizing a computer model which relates etch profiles of features on semiconductor substrates to a set of independent input parameters, the method comprising:
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(a) identifying values for one or more model parameters to be optimized; (b) receiving experimental reflectance spectra generated from optical measurements of one or more semiconductor substrates etched using an experimental etch process performed using values of the set of independent input parameters; (c) generating computed reflectance spectra from the model using the values for the set of independent input parameters specified in (b); and (d) modifying the values of the one or more model parameters identified in (a) and repeating (c) with the modified values of the one or more model parameters so as to reduce a metric indicative of the differences between the experimental reflectance spectra received in (b) and corresponding computed reflectance spectra generated in (c) with respect to the values of the set of independent input parameters, thereby producing modified values for the one or more model parameters for use in the computer model which relates etch profiles of features on semiconductor substrates to the set of independent input parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification