Projection objective for microlithography, projection exposure apparatus, projection exposure method and optical correction plate

US8228483B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Ulrich Loering · Schwäbisch Gmünd, DE
• Gerd Reisinger · Oberkochen, DE
• Franz-Josef Stickel · Aalen, DE
• Sonja Schneider · Lehrberg, DE
• Johann Trenkler · Trochtelfingen, DE
• Stefan Kraus · Bruchsal, DE
• Gordon Doering · Aalen, DE
• Aksel Goehnermeier · Aalen, DE

Key dates

• Filing date: Feb 2, 2010
• Grant date: Jul 24, 2012
• Expiry date: Jan 22, 2031

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/24612
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A projection objective is disclosed. The projection objective can include a plurality of optical elements arranged to image a pattern from an object field in an object surface of the projection objective to an image field in an image surface of the projection objective with electromagnetic operating radiation from a wavelength band around an operating wavelength λ. The plurality of optical elements can include an optical correction plate that includes a body comprising a material transparent to the operating radiation, the body having a first optical surface, a second optical surface, a plate normal substantially perpendicular to the first and second optical surfaces, and a thickness profile defined as a distance between the first and second optical surfaces measured parallel to the plate normal. The first optical surface can have a non-rotationally symmetric aspheric first surface profile with a first peak-to-valley value PV1>λ. The second optical surface can have a non-rotationally symmetric aspheric second surface profile with a second peak-to-valley value PV2>λ. A thickness of the optical correction plate can vary by less than 0.1*(PV1+PV2)/2 across the optical correction plate…