Illumination system of a microlithographic projection exposure apparatus

US8264668B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Damian Fiolka · Oberkochen, DE
• Manfred Maul · Aalen, DE
• Markus Schwab · Aalen, DE
• Wolfgang Seitz · Leingarten, DE
• Olaf Dittmann · Bopfingen, DE

Key dates

• Filing date: Jul 2, 2009
• Grant date: Sep 11, 2012
• Expiry date: Jul 12, 2030

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B5/1876
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

The disclosure relates to an illumination system of a microlithographic projection exposure apparatus. The illumination system can include a depolariser which in conjunction with a light mixing system disposed downstream in the light propagation direction at least partially causes effective depolarisation of polarised light impinging on the depolariser. The illumination system can also include a microlens array which is arranged upstream of the light mixing system in the light propagation direction. The microlens array can include a plurality of microlenses arranged with a periodicity. The depolariser can be configured so that a contribution afforded by interaction of the depolariser with the periodicity of the microlens array to a residual polarisation distribution occurring in a pupil plane arranged downstream of the microlens array in the light propagation direction has a maximum degree of polarisation of not more than 5%.