| 摘要 |
A beam delivery system of a projection exposure system comprises a laser generating a beam of laser light from a plurality of longitudinal laser modes in a cavity, wherein light generated by a single longitudinal laser mode has an average line widthλlat, wherein the laser light of the beam has, at each of respective lateral positions of the beam, a second line widthλlat corresponding to lateral laser modes, and wherein the laser light of the beam has, when averaged over a whole cross section thereof, a line widthλb corresponding to plural lateral laser modes, and whereinλm<λlat<λb, and wherein an optical delay apparatus disposed in the beam provides an optical path differenceΔl, wherein 0.8 ·λ0 2 ( 2 ·Δ λl ) <Δ l < 1.8 ·λ0 2 ( 2 ·Δ λl ) , whereinλ0 is an average wavelength of the light of the first beam of laser light, andΔλlat represents the second line width. |
