Control of a lithographic apparatus

摘要

A controller system for a pulsed radiation source is a closed-loop controller of minimum order, preferably first, to effect dead beat control. Performance indicators for a pulsed radiation source in a lithographic apparatus are based on Moving Averages, MA, and Moving Standard Deviations, MSD, of the error between target and actual pulse energies. The normalized indicators are given by: $where\; Epref(i)\; and\; Eperr(i)\; indicate\; reference\; energy\; per\; pulse\; and\; energy\; error\; per\; pulse\; for\; point\; i.\; and:$ \mathop{\mathrm{image}}$$