Patent attributes
A chamber lid assembly includes: a central channel having an upper portion and a lower portion and extending along a central axis; a housing at least partially defining a first and a second annular channel, each fluidly coupled to the central channel; a first plurality of apertures disposed along a horizontal plane through the housing to provide a multi-aperture inlet between the first annular channel and the central channel; a second plurality of apertures disposed along a horizontal plane through the housing to provide a multi-aperture inlet between the second annular channel and the central channel, wherein the first and the second plurality of apertures are angled differently with respect to the central axis so as to induce opposing rotational flow of gases about the central axis; and a tapered bottom surface extending from the lower portion of the central channel to a peripheral portion of the chamber lid assembly.