31 December 2009 Study of haze in 193nm high dose irradiated CaF2 crystals
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Crystalline calcium fluoride is one of the key materials for 193 nm lithography and is used for laser optics, beam delivery system optics and stepper/scanner optics. Laser damage occurs, when light is absorbed, creating defects in the crystal. Haze is known as a characteristic optical defect after high dose irradiation of CaF2 - an agglomeration of small scattering and absorbing centers. In order to prevent unnecessary damage of optical components, it is necessary to understand the mechanism of laser damage, the origin of haze and the factors that serve to prevent it. Stabilized M centers were described as reversible absorbing defects in CaF2, which can be annealed by lamp or laser irradiation. In this study the irreversible defects created by 193 nm laser irradiation were investigated.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ute Natura, Ute Natura, Stephan Rix, Stephan Rix, Martin Letz, Martin Letz, Lutz Parthier, Lutz Parthier, } "Study of haze in 193nm high dose irradiated CaF2 crystals", Proc. SPIE 7504, Laser-Induced Damage in Optical Materials: 2009, 75041P (31 December 2009); doi: 10.1117/12.836409; https://doi.org/10.1117/12.836409

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