Patent ID: 6590921
Filing Date: 2003-07-08
Classification: H01S

Abstract:
An ArF excimer laser device with a line-narrowing optical system comprising an echelle diffraction grating in a Littrow arrangement, a beam expansion prism system composed of at least three prisms arranged on the incident side of the echelle diffraction grating, and a slitwherein a blaze angle &thgr; of the echelle diffraction grating is 82Â° or less, a magnification rate M of the beam is 26 times or less, an oscillation pulse width Tis is 60 ns or less, a resonator length L is in a range of 1000 to 1350 mm and a slit width W is 1.0 mm or more, satisfying the relation (W+11) cos &thgr;/(LMTis0.853) <4.94Ã—10âˆ’6 â€ƒfor obtaining a 95% integrated line width of 1.15 pm or less without an etalon based coupler.