Catadioptric projection objective

US9279969B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Alexander Epple · Aalen, DE
• Vladimir Kamenov · Oberkochen, DE
• Toralf Gruner · Hennef (Sieg), DE
• Thomas Schicketanz · Aalen, DE

Key dates

• Filing date: Oct 9, 2014
• Grant date: Mar 8, 2016
• Expiry date: Oct 9, 2034

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70275
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Catadioptric projection objectives for microlithography include: a first partial objective for imaging an object field onto a first real intermediate image; a catadioptric partial objective having one concave mirror and a lens for imaging the first intermediate image onto a second real intermediate image; a third partial objective including an aperture stop and no more than four lenses between the aperture stop and an image field, the third partial objective for imaging the second intermediate image onto the image field; and a first folding mirror for deflecting the radiation from the object plane toward the concave mirror and a second folding mirror for deflecting the radiation from the concave mirror toward the image plane. The projection objective is an immersion projection objective. At least one surface of the lens in the catadioptric partial objective has an antireflection coating including at least six layers.