Patent ID: 7713760

Claim:
A method of monitoring a processing system for processing a substrate during the course of semiconductor manufacturing comprising: acquiring data from said processing system for a plurality of observations, said data comprising a plurality of data variables; determining one or more principal components of said data for said plurality of observations using principal components analysis; applying a first weighting factor to a first one of said plurality of data variables and a second weighting factor to a second one of said plurality of data variables during said principal components analysis; acquiring additional data from said processing system; determining at least one statistical quantity from one or more scores calculated from a projection of said additional data onto said one or more principal components determined by using said first weighting factor and said second weighting factor; determining a control limit for said at least one statistical quantity; and comparing said at least one statistical quantity to said control limit, wherein the first weighting factor is based on a first relative importance of the first one of said plurality of data variables, the second weighting factor is based on a second relative importance of the second one of said plurality of data variables, and the first relative importance is different from the second relative importance.