Gas discharge laser with improved beam path

US6795474B2 · kind B2 · utility

Assignee

• Cymer, LLC · US

Inventors

• William N. Partlo · Poway, US
• Richard L. Sandstrom · Encinitas, US
• Holzer K. Glatzel · San Diego, US
• Raymond F. Cybulski · San Diego, US
• Peter Clarke Newman · San Diego, US
• James K. Howey · Vista, US
• William G. Hulburd · San Diego, US
• John T. Melchior · San Diego, US
• Alex P. Ivaschenko · Village of La Jolla, US

Key dates

• Filing date: Nov 14, 2001
• Grant date: Sep 21, 2004
• Expiry date: Nov 14, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S3/2366
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An excimer laser with a purged beam path capable of producing a high quality pulsed laser beam at pulse rates in excess of 2,000 Hz at pulse energies of about 5 mJ or greater. The entire purged beam path through the laser system is sealed to minimize contamination of the beam path. A preferred embodiment comprises a thermally decoupled LNP aperture element to minimize thermal distortions in the LNP. This preferred embodiment is an ArF excimer laser specifically designed as a light source for integrated circuit lithography. An improved wavemeter is provided with a special purge of a compartment exposed to the output laser beam.