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AssigneeHitachi, Ltd.
InventorsNobuyuki Iriki, Tsutomu Okabe, Kenji Watanabe, Hisashi Maejima, Shinji Kuniyoshi
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A semiconductor integrated circuit device fabrication technique improves the accuracy of element qualities by considering the influence of interaction of element quality parameters in the quality control of semiconductor fabrication processes and also by improving the product yield estimation accuracy so that the production efficiency can be improved. An initial value of a membership function is first set and then a plurality of element quality parameters and a combined quality parameter are expressed by membership functions in fuzzy control in a semiconductor fabrication apparatus for automating a fabrication method by connecting a computer with various measuring instruments and various processors by communication devices. Moreover, the combined quality parameters are fuzzy-inferred from the element quality parameters using these membership functions, inference rules are adjusted by data of the actual processes, the membership functions of the obtained element quality parameters are converted into an element quality control standard, and the semiconductor integrated circuit device fabrication processes are controlled in accordance with the standard.
A semiconductor integrated circuit device fabrication method for quality control semiconductor integrated circuit device fabrication processes, comprising the steps of adjusting membership functions used in fuzzy inference to improve the accuracy of inferring yield of the semiconductor integrated circuit device by using fuzzy inference, and controlling the semiconductor integrated circuit device fabrication processes under a desirable element quality parameter state obtained from the adjusted membership functions.
A semiconductor integrated circuit device fabrication method for quality control, in semiconductor integrated circuit device fabrication processes, comprising the steps of fuzzy-inferring element quality parameters, adjusting parameters of membership functions of element qualities used in fuzzy inference to minimize inference errors, and controlling the semiconductor integrated circuit device fabrication processes by using the adjusted membership functions as a control standard of the element quality parameters.
A semiconductor integrated circuit device fabrication apparatus used in forming a semiconductor integrated device using fuzzy inference for quality control comprising the first step of expressing an element quality parameter control standard by a membership function in fuzzy control, a second step of fuzzy-inferring combined quality parameters by using a plurality of element quality membership functions, and a third step of minimizing the sum of the squares of combined quality parameter errors fuzzy-inferred by a plurality of combinations of measured element quality parameters and corresponding measured combined quality parameter errors by adjusting parameters of membership functions showing the standard of the element quality parameters, and controlling the semiconductor integrated circuit device fabrication processes by using the membership functions obtained through the adjustments in the third step as a control standard of the element quality parameters, comprising:
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