Patent ID: 7593912

Claim:
A method for evaluating reliance level of a virtual metrology system in product manufacturing, said method comprising: obtaining a plurality of sets of historical process data belonging to a production equipment, wherein a plurality of historical products are manufactured by said production equipment in accordance with said sets of historical process data respectively; obtaining a plurality of historical measurement values from a measurement equipment, wherein said historical measurement values are the actual measurement values of said historical products measured by said measurement equipment; establishing a conjecture model by using said sets of historical process data and said historical measurement values, wherein said conjecture model is built in accordance with a conjecture algorithm; establishing a reference model by using said sets of historical process data and said historical measurement values, wherein said reference model is built in accordance with a reference algorithm, and said conjecture algorithm is different from said reference algorithm; obtaining a set of process data collected from said production equipment for manufacturing a first product and inputting said set of process data to said conjecture model, thereby computing a virtual measurement value of said first product and a standardized virtual measurement value of said first product; inputting said set of process data of said first product to said reference model, thereby computing a reference prediction value of said first product and a standardized reference prediction value of said first product; and respectively calculating an overlap area between the statistical distribution of said at least one standardized virtual measurement value of said first product and the statistical distribution of said at least one standardized reference prediction value of said first product, thereby generating a reliance index (RI) of said standardized virtual measurement value, wherein said reliance index is higher when said overlap area is larger, representing that the reliance level of said standardized virtual measurement value corresponding to said reliance index is higher.