| 摘要 |
PURPOSE:To obtain a window with the excellent resistance to thermal shock by using a dense alumina plate where at least a part coming into contact with a vacuum is composed of a porous layer. CONSTITUTION:A microwave 1 is introduced into a vacuum container through a microwave transmission window which is used to keep a vacuum and to introduce the microwave; a plasma is generated; a process is executed. As an insulator constituting the microwave transmission window at this microwave plasma processing system, a dense alumina plate 21 where at least a part coming into contact with the vacuum is composed of a porous layer 22 is used. The alumina plate for said microwave transmission window is manufactured, e.g., in such a way that the dense alumina plate 21 is coated with porous alumina by injecting the molten alumina. By this setup, because the thermal conduction of the porous alumina is inferior to that of the dense alumina, the resistance to thermal shock of the porous alumina is higher than that of the dense alumina and the coefficient of thermal expansion for both is almost the same, it is possible to obtain the microwave transmission window with the high resistance against thermal shock.
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