摘要 |
<p>A lithographic projection apparatus comprising: a radiation system LA, Ex, IN, CO for supplying a projection beam PB of electromagnetic radiation; a mask table MT provided with a mask holder for holding a mask MA; a substrate table WT provided with a substrate holder for holding a substrate W; a projection system PL for imaging an irradiated portion of the mask MA onto a target portion C of the substrate W, whereby the electromagnetic radiation has a wavelength less than 200 nm, and the apparatus further comprises means for maintaining the energy dose Ds at substrate level at a substantially constant value, by substantially compensating for irradiation-induced drift in the intensity Is at substrate level. <IMAGE></p> |