ASML Holding N.V.
Method of monitoring and device manufacturing method

Abstract:

A method of monitoring a device manufacturing process, the method including; obtaining an estimated time variation of a process parameter; determining, on the basis of the estimated time variation, a sampling plan for measurements to be performed on a plurality of substrates to obtain information about the process parameter; measuring substrates in accordance with the sampling plan to obtain a plurality of measurements; and determining an actual time variation of the process parameter on the basis of the measurements.