Substrates for mirrors for EUV lithography and their production

US8870396B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Julian Kaller · Oberkochen, DE
• Wilfried Clauss · Lörrach, DE
• Michael Gerhard · Aalen, DE

Key dates

• Filing date: Nov 2, 2012
• Grant date: Oct 28, 2014
• Expiry date: Nov 2, 2032

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C2201/42
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

For the production of mirrors for EUV lithography, substrates are suggested having a mean relative thermal longitudinal expansion of no more than 10 ppb across a temperature difference ΔT of 15° C. and a zero-crossing temperature in the range between 20° C. and 40° C. For this purpose, at least one first and one second material having low thermal expansion coefficients and opposite gradients of the relative thermal expansion as a function of temperature are selected and a substrate is produced by mixing and bonding these materials.