Microlithographic apparatus

US9348234B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Boris Bittner · Roth, DE
• Norbert Wabra · Werneck, DE
• Sonja Schneider · Lehrberg, DE
• Ricarda Schoemer · Zusmarshausen, DE
• Martin von Hodenberg · Oberkochen, DE
• Hendrik Wagner · Bielefeld, DE
• Rumen Iliew · Oberkochen, DE

Key dates

• Filing date: Sep 4, 2015
• Grant date: May 24, 2016
• Expiry date: Sep 4, 2035

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70891
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A projection objective of a microlithographic projection apparatus has a wavefront correction device (42) comprising a mirror substrate (44; 44a, 44b) that has two opposite optical surfaces (46, 48), through which projection light passes, and a circumferential rim surface (50) extending between the two optical surfaces (46, 48). A first and a second optical system (OS1, OS2) are configured to direct first and second heating light (HL1, HL2) to different portions of the rim surface (50) such that at least a portion of the first and second heating light enters the mirror substrate (44; 44a, 44b). A temperature distribution caused by a partial absorption of the heating light (HL1, HL2) results in a refractive index distribution inside the mirror substrate (44; 44a, 44b) that corrects a wavefront error. At least the first optical system (OS1) comprises a focusing optical element (55) that focuses the first heating light in a focal area (56) such that the first heating light emerging from the focal area (56) impinges on the rim surface (50).