| 摘要 |
PURPOSE:To balance control currents flowed in a wafer in all sections by individually leading a plurality of control lead wirings from the outer peripheral and inner portions. CONSTITUTION:A shallow annular groove 21a is formed on the inner peripheral surface of an insulating enclosure made of a ceramic material, and an annular conductive layer 22 is formed of silver material by brazing. A lead leading tube 23 is made of the same material as a lead leading tube 16, and airtightly secured through a radial direction to an insulating enclosure 21 at symmetrical positions of 180 deg.. The tube 23 is bonded by brazing to the layer 22 together with the tube 16, and electrically connected with the same potential. |
