EUV exposure apparatus with reflective elements having reduced influence of temperature variation

US10684551B2 · kind B2 · utility

Assignees

• Carl Zeiss SMT GmbH · DE
• ASML NETHERLANDS B.V. · NL

Inventors

• Norman Baer · Aalen, DE
• Ulrich Loering · Schwäbisch Gmünd, DE
• Oliver Natt · Aalen, DE
• Gero Wittich · Aalen, DE
• Timo Laufer · Stuttgart, DE
• Peter Kuerz · Aalen, DE
• Guido Limbach · Aalen, DE
• Stefan Hembacher · Bobingen, DE
• Holger Walter · Aalen, DE
• Yim-Bun Patrick Kwan · Aalen, DE
• Markus Hauf · Ulm, DE
• Franz-Josef Stickel · Aalen, DE
• Jan Bernard Plechelmus Van Schoot · Eindhoven, NL

Key dates

• Filing date: Apr 23, 2019
• Grant date: Jun 16, 2020
• Expiry date: Apr 23, 2039

Classification

• Technology area (CPC G): Physics
• CPC primary: G21K2201/064
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A projection lens of an EUV-lithographic projection exposure system with at least two reflective optical elements each comprising a body and a reflective surface for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light, wherein the bodies of at least two reflective optical elements comprise a material with a temperature dependent coefficient of thermal expansion which is zero at respective zero cross temperatures, and wherein the absolute value of the difference between the zero cross temperatures is more than 6K.