Abstract: A method of refurbishing a wall of a plasma process chamber which has a surface with a magnet assembly fitted thereon. The magnet assembly has an expandable hollow collar with a plurality of magnets inside. In the method, the diameter of the hollow collar of the magnet assembly is expanded to remove the hollow collar from the wall. The surface of the wall is cleaned. The hollow collar of the original magnet assembly, or of another magnet assembly, is then snap fitted back onto the surface of the wall.

Abstract: A magnet assembly for a plasma process chamber has a hollow collar comprising a cross-section that is absent seams. The hollow collar has an open end face and a cap is provided to seal the open end face of the collar. A plurality of magnets are in the hollow collar, the magnets being insertable through the open end face. The collar is capable of being snap fitted onto the chamber wall. The magnet assembly can also comprise one or more of the collars such that the collars, when installed, form a substantially continuous ring about a chamber wall.