Four KHz gas discharge laser system

US6882674B2 · kind B2 · utility

Assignee

• Cymer, LLC · US

Inventors

• Christian J. Wittak · San Diego, US
• William N. Partlo · Poway, US
• Richard L. Sandstrom · Encinitas, US
• Paul C. Melcher · El Cajon, US
• David M. Johns · West Newbury, US
• Robert B. Saethre · San Diego, US
• Richard M. Ness · San Diego, US
• Curtis Rettig · Vista, US
• Robert A. Shannon · Ramona, US
• Richard C. Ujazdowski · Poway, US
• Shahryar Rokni · Carlsbad, US
• Scott T. Smith · San Jose, US
• Stuart L. Anderson · San Diego, US
• John M. Algots · San Diego, US
• Ronald Spangler · Somerville, US
• Igor V. Fomenkov · San Diego, US
• Thomas D. Steiger · San Diego, US
• Jerome A. Emilo · San Diego, US
• Clay C. Titus · San Diego, US
• Alex P. Ivaschenko · Village of La Jolla, US
• Paolo Zambon · Campbell, US
• Gamaralalage G. Padmabandu · San Diego, US
• Mark Branham · Trafalgar, US
• Sunjay Phatak · South Lake Tahoe, US
• Raymond F. Cybulski · San Diego, US

Key dates

• Filing date: Dec 21, 2001
• Grant date: Apr 19, 2005
• Expiry date: Jul 15, 2022

Classification

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

Abstract

The present invention provides an excimer laser capable of producing a high quality pulsed laser beam at pulse rates of about 4,000 Hz at pulse energies of about 5 mJ or greater. A preferred embodiment is an ArF excimer laser specifically designed as a light source for integrated circuit lithography. An improved wavemeter with special software monitors output beam parameters and controls a very fast PZT driven tuning mirror and the pulse power charging voltage to maintain wavelength and pulse energy within desired limits. In a preferred embodiment two fan motors drive a single tangential fan which provides sufficient gas flow to clear discharge debris from the discharge region during the approximately 0.25 milliseconds between pulses.