Four KHz gas discharge laser

US6757316B2 · kind B2 · utility

Assignee

• Cymer, LLC · US

Inventors

• Peter Clarke Newman · San Diego, US
• Thomas Patrick Duffey · 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
• Vladimir B. Fleurov · Escondido, 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
• Xiaojiang Pan · San Diego, US
• Vladimir Kulgeyko · San Diego, 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

Key dates

• Filing date: May 11, 2001
• Grant date: Jun 29, 2004
• Expiry date: Oct 7, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S3/2308
• 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.