Patent ID: 8896816

Claim:
A projection exposure method for the exposure of a radiation-sensitive substrate arranged in the region of an image surface of a projection objective with at least one image of a pattern of a mask arranged in the region of an object surface of the projection objective, comprising: generating laser radiation having a spectral intensity distribution I(ω) dependent on an angular frequency ω, wherein the laser radiation is characterized by an aberration parameter α in accordance with: a := ∫ I ⁡ ( ω ) ⁢ ω 2 ⁢ ⅆ ω ∫ I ⁡ ( ω ) ⁢ ⅆ ω and a coherence time τ in accordance with: τ = ∫ I ⁡ ( ω ) 2 ⁢ ⅆ ω [ ∫ I ⁡ ( ω ) ⁢ ⅆ ω ] 2 introducing the laser radiation into an illumination system for generating an illumination radiation directed onto the mask; imaging the pattern onto the substrate using a projection objective; wherein the spectral intensity distribution is set so that ατ 2 ≦0.3.