| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing an optical member comprising an MgF<SB POS="POST">2</SB>single crystal in which crystallinity needed or a polarizing material of a polarized illumination exposing device is good and a main axis direction for transmitting light is <100> direction. <P>SOLUTION: A seed crystal body in which the <100> axis is inclined from 7° to 45° preferably 7° to 15° directed from a vertical direction to the <100> direction is used as the seed crystal body when producing the MgF<SB POS="POST">2</SB>singly crystal by a Czochralski method. By using the inclined seed crystal body, an axial direction of the grown single crystal body is inclined the same angle, however, the crystallinity of the single crystal body grown in such a manner exhibits crystallinity comparable to the case in which a growing direction is the <001> axis. The obtaining efficiency of a plate-like body having parallel faces comprising the ä100} face is good compared to the case in which the growing direction is <001> direction. <P>COPYRIGHT: (C)2013,JPO&INPIT |
