摘要 |
A projection exposure apparatus for manufacturing semiconductor elements has a control system for correcting changes in imaging characteristics with high precision on a real-time basis and for correcting imaging characteristics of a projecting lens on the basis of information associated with the history of light incident on the projection lens, wherein even if the history information of incident light is lost, due to a power failure, for example, or an error occurs in the information, correction control for the imaging characteristics can be restored with high precision.
|