Illumination system of a microlithographic projection exposure apparatus

US8928859B2 · 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: Aug 1, 2012
• Grant date: Jan 6, 2015
• Expiry date: May 18, 2033

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 depolarizer which in conjunction with a light mixing system disposed downstream in the light propagation direction at least partially causes effective depolarization of polarized light impinging on the depolarizer. 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 depolarizer can be configured so that a contribution afforded by interaction of the depolarizer with the periodicity of the microlens array to a residual polarization distribution occurring in a pupil plane arranged downstream of the microlens array in the light propagation direction has a maximum degree of polarization of not more than 5%.