To realize a method for detecting variations in conditions (drift of the exposure
and drift of the focus) in exposure equipment at a product wafer level in lithography
process, the process is specified in such a way that calculation results of feature
quantities such as electron beam images, line profiles, dimensions, etc. under
various sets of the exposure and the focus are stored as a library, and an electron
beam image of the product wafer is compared with these pieces of data in the library
so that detection of drifts of the exposure and the focus a check of the results
on the screen can easily be performed.
