Patent ID: 7599817

Claim:
An abnormality cause specifying method comprising: acquiring, for each fabrication lot, a plurality of types of inspection data in a plurality of fabrication steps of a product fabrication process; generating a feature amount by standardizing the inspection data for each type; generating, for each fabrication lot, a trial data set by selecting the feature amount corresponding to the inspection data of a type on an adoption level for each trial experiment in a two-level orthogonal table, by using two levels of the two-level orthogonal table as the adoption level and a non-adoption level of a type of inspection data, and using a factor of the two-level orthogonal table as a type of inspection data; calculating, for the trial data set, a trial similarity representing a degree of similarity between the fabrication lots; generating, for each fabrication lot, a trial set by extracting another fabrication lot whose trial similarity is not less than a threshold value; calculating, for each trial experiment and for each fabrication step, a step test value representing a degree of a causal relation of the fabrication lot forming the trial set to a plurality of fabrication apparatuses provided in a fabrication step, wherein the step test value is a value indicating which fabrication apparatus of the plurality of fabrication apparatuses is used for the fabrication lot forming the trial set; setting, for each trial experiment, a step test value whose degree of a nominal-the-best characteristic is the largest of the trial set as a trial experiment test value; generating, for each fabrication lot, an optimum data set including the feature amount corresponding to the type of inspection data for which the adoption level is selected, on the basis of a factorial effect diagram for optimizing the nominal-the-best characteristic of the trial experiment test value by using the adoption level and the non-adoption level of each type; calculating, for the optimum data set, an optimum similarity representing a degree of similarity between the fabrication lots; generating, for each fabrication lot, an optimum set by extracting another fabrication lot whose optimum similarity is not less than a threshold value; calculating, for each fabrication step, an optimum test value representing a degree of a causal relation of the fabrication lot forming the optimum set to a plurality of fabrication apparatuses provided in the fabrication step, the optimum test value being a value indicating which fabrication apparatus of the plurality of fabrication apparatuses is used for the fabrication lot forming the optimum set; determining, for each optimum set, whether the causal relation of the optimum set to the fabrication apparatuses is significant, on the basis of the optimum test value; and extracting, by an extractor, for each optimum set, the fabrication apparatus as an object of the causal relation found to be significant, as an abnormality cause.