Patent ID: 6475353
Filing Date: 2002-11-05
Classification: C23C,H01J

Abstract:
An apparatus for sputter depositing a layer of material on a substrate comprising:a sputtering chamber having an internal conductive wall which defines a processing space; a substrate mount positioned in the processing space for supporting a substrate therein; a sputter target mount positioned in the processing space for supporting a target therein opposite said substrate mount; a power source for biasing a target and exciting a process gas introduced in the processing space into a plasma such that the plasma will sputter material from a target supported on said target mount and the sputtered material will deposit on a substrate supported on said substrate mount and on a surface of the chamber wall to form respective material layers thereon, a surface of the internal chamber wall operable for providing an electrical reference for the plasma during sputter deposition; a conductive shield positioned in the processing space between the target mount and the substrate mount and configured for capturing a portion of the sputtered material which would otherwise deposit on the chamber wall surface during sputter deposition; a source of ground potential, the conductive shield being coupled to the source of ground potential for grounding the shield during sputter deposition; the conductive shield operable for reducing the amount of sputtered material which will deposit on a portion of the chamber wall surface and maintaining said chamber wall surface portion as a generally stable electrical reference for the plasma, and further including a plurality of apertures formed therein, the apertures comprising a cumulative area in the range of approximately 10% to 50% of the area of an inner surface of the shield for being operable for passing plasma therethrough during sputter deposition to contact said stable electrical reference; at least one of the shield apertures having at least one dimension in the range of approximately 0.25 to 2.0 times the mean free path length of a process gas to be introduced into the chamber; whereby a stable and continuous sputter deposition process may be achieved.