首页>
外国专利>
PREPARATION OF 157NM TRANSMITTING BARIUM FLUORIDE CRYSTALS WITH PERMEABLE GRAPHITE
PREPARATION OF 157NM TRANSMITTING BARIUM FLUORIDE CRYSTALS WITH PERMEABLE GRAPHITE
展开▼
机译:渗透性石墨的157NM透射型氟化钡晶体的制备
展开▼
页面导航
摘要
著录项
相似文献
摘要
The object of the present invention is a process of preparing an optical fluoride crystal containing barium fluoride, which comprises loading a crucible with a barium fluorine starting material crystal feedstock which contains at least one oxide as impurity, and an effective and non-excess amount of at least one fluorinating agent which is solid at ambient temperature, melting said mixture within said crucible, growing the crystal, by controlled cooling of the molten mixture, controlled cooling of said crystal to ambient temperature, recovering said crystal; and which is characterised in that the oxide(s) resulting from the reaction between said fluorinating agent(s) and said oxide(s), the impurity or impurities, can be discharged from said crucible, in view of the intrinsic permeability of the material constituting it. Said process is particularly adapted for preparing 157 nm transmitting lithography excimer laser optical fluoride crystals in graphite crucibles.
展开▼