Method and apparatus for multidomain data analysis
First Claim
1. A system for evaluating parameters of a semiconductor wafer or wafer set comprising:
- a source which generates a probe beam which is transmitted through a lens and onto a semiconductor wafer;
a detector which detects the probe beam after it is reflected off the semiconductor wafer, and the detector outputs signals based on the probe beam reflected of the semiconductor wafer;
a processor coupled to the detector to receive the signals; and
wherein the processor is operable to generate measurement data, based on the received signals, for multiple points on the semiconductor wafer or wafer set, and to define multiple domains, wherein a domain has corresponding measured data, and to determine an optimum group of parameter values for each domain, wherein to determine the optimum group for each domain the processor is operable to;
associate different sets of theoretical semiconductor wafer parameter values with each domain;
compare a first set of theoretical measurement data, derived from a first set of theoretical semiconductor wafer parameter values associated with a domain, to the measured data corresponding to the domain; and
generate a new set of theoretical semiconductor wafer parameter values to be associated with the domain based on the comparing in a manner so as to associate increasingly more optimal theoretical semiconductor wafer parameter values with the domain, wherein the generation of the new set of theoretical semiconductor parameter values includes migrating at least one theoretical semiconductor parameter value from a set of theoretical semiconductor parameter values that has been associated with a different domain.
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Abstract
An optical measuring device generates a plurality of measured optical data from inspection of a thin film stack. The measured optical data group naturally into several domains. In turn the thin film parameters associated with the data fall into two categories: local and global. Local “genes” represent parameters that are associated with only one domain, while global genes represent parameters that are associated with multiple domains. A processor evolves models for the data associated with each domain, which models are compared to the measured data, and a “best fit” solution is provided as the result. Each model of theoretical data is represented by an underlying “genotype” which is an ordered set of the genes. For each domain a “population” of genotypes is evolved through the use of a genetic algorithm. The global genes are allowed to “migrate” among multiple domains during the evolution process. Each genotype has a fitness associated therewith based on how much the theoretical data predicted by the genotype differs from the measured data. During the evolution process, individual genotypes are selected based on fitness, then a genetic operation is performed on the selected genotypes to produce new genotypes. Multiple generations of genotypes are evolved until an acceptable solution is obtained or other termination criterion is satisfied.
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Citations
5 Claims
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1. A system for evaluating parameters of a semiconductor wafer or wafer set comprising:
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a source which generates a probe beam which is transmitted through a lens and onto a semiconductor wafer; a detector which detects the probe beam after it is reflected off the semiconductor wafer, and the detector outputs signals based on the probe beam reflected of the semiconductor wafer; a processor coupled to the detector to receive the signals; and wherein the processor is operable to generate measurement data, based on the received signals, for multiple points on the semiconductor wafer or wafer set, and to define multiple domains, wherein a domain has corresponding measured data, and to determine an optimum group of parameter values for each domain, wherein to determine the optimum group for each domain the processor is operable to;
associate different sets of theoretical semiconductor wafer parameter values with each domain;
compare a first set of theoretical measurement data, derived from a first set of theoretical semiconductor wafer parameter values associated with a domain, to the measured data corresponding to the domain; and
generate a new set of theoretical semiconductor wafer parameter values to be associated with the domain based on the comparing in a manner so as to associate increasingly more optimal theoretical semiconductor wafer parameter values with the domain, wherein the generation of the new set of theoretical semiconductor parameter values includes migrating at least one theoretical semiconductor parameter value from a set of theoretical semiconductor parameter values that has been associated with a different domain. - View Dependent Claims (2, 3, 4, 5)
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Specification