Patent ID: 8268142

Claim:
Apparatus for sputtering, comprising: a vacuum chamber defined by at least one side wall, a base and a cover; at least one first electrode having a first surface arranged in the vacuum chamber; a counter electrode having a surface arranged in the vacuum chamber, and a RF generator, the RF generator being configured to apply a RF electric field across the at least one first electrode and the counter electrode so as to ignite a plasma between the first electrode and the counter electrode, wherein the counter electrode comprises at least two cavities in communication with the vacuum chamber, the cavities each having dimensions such that a plasma can be formed in the cavity, the counter electrode comprises a side wall frame and at least three additional electrically conductive members defining the at least two cavities, the counter electrode is arranged in peripheral regions of the vacuum chamber, the additional electrically conductive members protrude from the side wall frame, the additional electrically conductive members are arranged spaced at a distance and generally parallel to one another, the additional electrically conductive members each comprises a ring, and the cavities are ring-shaped.