Title: Illumination unit for an optical apparatus
Application Number: 96193465 Application Date: 1997.07.16
Publication Number: 1182486 Publication Date: 1998.05.20
Approval Pub. Date: 2003.12.10 Granted Pub. Date: 2003.12.10
International Classifi-cation: G02B27/14;G03F7/20
Applicant(s) Name: ASM Lithography B. V. Address:
Inventor(s) Name: H. Van Der Laan;J. C. H. Mulkens;J. M. D. Stoeldra
Attorney & Agent: zou guangxin
Abstract:
    Illumination unit (2) for an optical system, including an illumination system (1) which comprises, in this order, a radiation source (3) and a first optical integrator (11). The illumination unit (2) further comprises a detection system (45) including a radiation-sensitive detector (47). The illumination system (1) comprises a second optical integrator (13). A prism system (15) comprising at least one prism (17) is provided in the optical path between the two integrators (11, 13). The prism system (15) has a coupling-out surface via which light can be coupled out of the illumination system (1), and an exit surface via which light can be coupled out of the prism system (15), without the intensity in the main light path being essentially influenced. The detection system (45) is arranged proximate to the exit surface of the prism system (15) and comprises light-integrating means. The invention also relates to an optical apparatus (100), particularly a lithographic projection apparatus, provided with such an illumination unit (2).
Time: 5