LOWER ELECTRODE ASSEMBLY OF PLASMA PROCESSING CHAMBER

摘要

A lower electrode assembly for use in a plasma processing chamber comprises a metal base and upper and lower edge rings. The metal base comprises metal plates brazed together and forming a brazed line on a lower side surface of the base, an edge ring support surface extending horizontally inwardly from the lower side surface and an upper side surface above the edge ring support surface. The upper edge ring comprises a lower surface mounted on the edge ring support surface and the lower edge ring surrounds the lower side surface of the base with a gap between opposed surfaces of the upper and lower edge rings and between the lower edge ring and the outer periphery of the base. The gap has an aspect ratio of total gap length to average gap width sufficient to impede arcing at the location of the braze line.