| 摘要 |
PROBLEM TO BE SOLVED: To provide a BaLiF<SB>3</SB>single crystal excellent in transmissivity of vacuum ultraviolet (VUV) light of 200 nm or shorter wavelength and excellent in laser resistance hardly suffering from the damage by laser light irradiation or the like, which is promising for an optical member for VUV light transmission, particularly for a last lens of an immersion exposure device. SOLUTION: This BaLiF<SB>3</SB>single crystal contains Mg and K, and the content ratio of these elements satisfies, in terms of mole, that Mg/(Li+Mg) is in the range of 0.001-0.02, and K/(Ba+K) is in the range of 0.001-0.02. COPYRIGHT: (C)2009,JPO&INPIT
|
