Patent ID: 6627900
Filing Date: 2003-09-30
Classification: G06N,H01J

Abstract:
A method, based on a genetic algorithm, for optimizing parameters of an optical system used in a charged-particle-beam (CPB) optical system, the method comprising:(a) regarding each respective value of a respective parameter as a respective gene; (b) regarding each respective combination of values of the parameters as a respective chromosome and each respective configuration of the CPB optical system according to the respective chromosome as a respective species; (c) each parameter having a respective initial-condition gene, wherein each of NA species in a group A comprises a respective chromosome of the initial-condition genes; (d) defining an evaluation function, wherein values of the evaluation function are related to respective qualities of a performance characteristic of the CPB optical system, and establishing a threshold value for the evaluation function; (e) from the group-A species, selecting a group B including NB species (wherein NB&lE;NA) in which the constituent species have higher respective values of the evaluation function than species not selected to be in the group B; (f) from the group-B species, and based on a selection criterion, selecting groups CND, in which each group includes NC individuals, to produce a group D including ND species, wherein each species in group D comprises a respective chromosome produced by recombination of one or more genes from respective chromosomes of species in the group CND; (g) producing the group D of ND species from the groups CND; (h) from the group D, selecting a new group B including NB species; (i) repeating steps (e)-(h) a predetermined number of times or until a species is produced in group D having a respective value of the evaluation function that exceeds the threshold; and (j) employing the species produced in step (i) to define the respective combination of values of the parameters for configuring the components or for operating the components in the coordinated manner.