Method and apparatus for deposition of low dielectric constant materials

A showerhead for distributing gases in a processing chamber comprising:

• a face plate having a plurality of at least partially tapered holes formed therethrough, each hole including a restrictive section, a center passage section, and an opening section;
• an annular body having a first end coupled to a first side of the face plate;
• a mounting flange coupled to a second end of the annular body;
• and
• an annular lip extending from a second side of the face plate opposite the mounting flange and defining an angle of between about 80 and about 90 degrees relative to the face plate, wherein the lip is adapted at least partially for confining a plasma proximate the face plate.

A processing chamber comprising:

• a chamber body;
• a lid disposed on the chamber body;
• a substrate support disposed in the chamber body;
• a face plate having a plurality of at least partially tapered holes formed therethrough, each hole including a restrictive section, a center passage section, and an opening section, the face plate disposed between the lid and the substrate support;
• an annular body having a first end coupled to a first side of the face plate;
• a mounting flange coupled to a second end of the annular body and coupled to the lid;
• and
• an annular a lip extending a second side of the face plate opposite the mounting flange and defining an angle of between about 80 and about 90 degrees relative to the face plate, wherein the lip is adapted at least partially for confining a plasma proximate the face plate, an inner diameter of the lip having a diameter less than a diameter of the substrate support.