Process gas inlet and distribution passages

A processing chamber gas distribution system comprising:

• a chamber dome section having an outer surface circumscribing a perimeter of said dome section;
• a gas feed ring having an inner surface facing and spaced from said outer surface of said chamber dome section to provide a generally continuous annular gas distribution channel between said inner surface and said outer surface, wherein said gas feed ring includes seal features to seal between said chamber dome section and a circumferential wall of a processing chamber, wherein said wall of said processing chamber includes a shelf recess;
• a gas distribution ring configured to be supported in said shelf recess, said ring having a top surface facing and generally in contact with said annular gas distribution channel to obstruct gas flowing from said gas distribution channel;
• said distribution ring including a set of gas passages from said opening of said gas distribution channel to an inside of said processing chamber.

In an evacuable processing chamber having a dome for containing a substrate fabrication process and gas channels adapted to transmit process gas into the interior of the chamber, the improvement comprising:

• a first annular generally flat end surface defining the outlet of the dome, and orthogonal to the dome axis of symmetry;
• a second annular end surface on said dome located outwardly of and intersecting said first end surface;
• a first ring positioned coaxially with said chamber at an outlet thereof and having generally flat parallel faces, one of which overlaps said first end surface while extending outwardly of said second end surface;
• a second ring having a generally cylindrical inner face and positioned coaxially with said dome, with said inner face and said second end surface in an opposed facing relationship so as to define a confined thin annular space about said second end surface, said second ring having defined therein at least one passageway opening into said annular space and adapted to communicate with an external gas source;
• said first ring being provided with a plurality of surface grooves extending from the innermost edge of said one surface outwardly to communicate with said annular space;
• whereby gas may be evenly injected via said internal passageway, the annular space, and the grooves into the process chamber in a pattern controllable by the positions and configuration of said grooves.