| 摘要 |
The invention features a system for microlithography that includes a mercury light source emitting radiation at multiple mercury emission lines, a projection objective positioned to receive radiation emitted by the mercury light source, and a stage to position a wafer relative to the projection objective. During operation, the projection objective directs radiation from the light source to the wafer, where the radiation at the wafer includes energy from more than one of said emission lines. Optical lens systems for use in said projection objective comprise four lens groups, arranged symmetrically, each having two lenses made of silica, the first and second lens groups using two different materials and are designed to optimise chromatism and image curvature. |
