Patent attributes
A stage has a plate, a first seal surface, a stem, a second seal surface, a cover, a conductor and a flow path. A heater is embedded in the plate. A terminal for supplying power to the heater is exposed at one surface of the plate. The first seal surface is provided on the plate, shaped like a ring and surrounds the terminal. The stem is shaped like a hollow cylinder, surrounds the terminal and supports the plate. The second seal surface is provided on that end of the stem which supports the plate, and is shaped like a ring. The cover closes an open end of the stem, which is opposite to the end which supports the plate. The conductor passes through the cover into the stem and is connected to the terminal. The flow path is provided in the cover, for supplying inert gas into the stem at a pressure equal to or higher than the pressure of process gas present outside the stem.
