| 摘要 |
PURPOSE:To uniformly treat by rotatably providing a magnet element in a plane perpendicularly to an electric field, and alternately forming N- and S-poles of a magnet at a magnet securing plate in a point-symmetrical manner with respect to the rotating center, and forming the poles of the both ends in the same polarity. CONSTITUTION:A magnet element 60a is composed of a yoke 61 of a magnet securing plate and N- and S-poles 62a, 63a of a magnet, which poles are alternately disposed on the yoke 61 in a point-symmetrical manner with respect to the rotating center. since a range that radial magnetic flux density Br becomes small on the pole and a range that Br becomes large between the poles exist at the same ratio at the arbitrary radial R position from the rotating center of the element 60a, the mean radial density Brm at one revolution time becomes the same at any position. Since the line of magnetic force generated over both ends of the element 60a is eliminated, the magnetic flux density of the same magnitude can be obtained between the individual poles. Thus, the entire surface to be treated of the wafer is exposed uniformly by strong plasma and etched uniformly at large etching speed. |
