Extended dark space shield

A substrate processing chamber, comprising:

• a chamber body having a substrate support disposed therein;
• a lid disposed atop the chamber body;
• a target assembly coupled to the lid opposite the substrate support, the target assembly including a target of material to be deposited on a substrate;
• and a process shield having a central opening passing through a body of the process shield and defining a processing volume of the substrate processing chamber, wherein the process shield comprises an annular dark space shield fabricated from a ceramic material and an annular ground shield fabricated from a conductive material, and wherein a length of the annular ground shield is about 4 inches to about 8 inches and wherein a length of the annular dark space shield is about 2 inches to about 5 inches, and wherein the length of the annular ground shield is longer than the length of the annular dark space shield, wherein the annular ground shield comprises a first portion disposed about an outer surface of the annular dark space shield, and wherein the annular dark space shield is supported on a spacer ring atop the annular ground shield;
• wherein the annular ground shield comprises a second portion with a top of the second portion disposed adjacent to and under a lowermost edge of the annular dark space shield, wherein an inner surface of the second portion is approximately aligned with an inner surface of the annular dark space shield, and wherein the spacer ring forms a gap between the lowermost edge of the annular dark space shield and the top of the second portion of the annular ground shield, the gap extending upwardly and outwardly, such that the gap terminates at a physical contact juncture between a vertical surface of the outer surface of the annular dark space shield and a vertical surface of an inner surface of the first portion of the annular ground shield, the gap separating at least a portion of the first portion of the annular ground shield from the outer surface of the annular dark space shield.

An apparatus for use in a physical vapor deposition substrate processing chamber, comprising:

• a process shield having a central opening passing through a body of the process shield and defining a processing volume of the substrate processing chamber, wherein the process shield comprises an annular dark space shield fabricated from a ceramic material and an annular ground shield fabricated from a conductive material, and wherein the length of the annular ground shield is about 4 inches to about 8 inches and the length of the annular dark space shield is about 2 inches to about 5 inches, wherein the annular dark space shield comprises an outer surface and an inner surface, and wherein the annular ground shield comprises an inner surface having a first portion disposed about an outer surface of the annular dark space shield and a second portion disposed below the annular dark space shield and exposed to a substrate processing volume of the processing chamber, wherein an inner surface of a top of the second portion is aligned with an inner surface of a bottom of the annular dark space shield, and wherein the annular dark space shield is supported on a spacer ring atop the annular ground shield;
• wherein the spacer ring forms a gap between a bottom edge of the annular dark space shield and a top of the second portion of the annular ground shield, the gap extending upwardly and outwardly, such that the gap terminates at a physical contact juncture between a vertical portion of the outer surface of the annular dark space shield and a vertical portion of the inner surface of the first portion of the annular ground shield, the gap separating at least a portion of the first portion of the annular ground shield from the outer surface of the annular dark space shield.