Staggered ribs on process chamber to reduce thermal effects

A reaction chamber, comprising:

• a chamber upper wall and a chamber lower wall, each wall having an inner surface and an outer surface and defining a reaction space therebetween;
• an inlet flange secured at a forward end of said chamber to said upper and lower walls;
• an outlet flange secured at a rearward end of said chamber to said upper and lower walls;
• a substrate support provided within the reaction space, the substrate support having a central axis around which the substrate support rotates;
• a heat source provided above the chamber;
• a heat source provided below the chamber;
• a plurality of forward ribs provided on the outer surface of the chamber upper wall and chamber lower wall, said forward ribs being located between the central axis of the substrate support and the inlet flange, wherein said forward ribs form a shadow onto the substrate support in a forward portion of the reaction space;
• and
• a plurality of rearward ribs provided on the outer surface of the chamber upper wall and chamber lower wall, said rearward ribs being located between the central axis of the substrate support and the outlet flange, wherein said rearward ribs form a shadow onto the substrate support in a rearward portion of the reaction space;
• wherein a majority of the shadows formed by the forward ribs have a mirrored projection in the rearward portion of the reaction space that falls substantially between shadows of the rearward ribs, and a majority of the shadows formed by the rearward ribs have a mirrored projection in the forward portion of the reaction space that falls substantially between shadows of the forward ribs.

A reaction chamber, comprising:

• a chamber upper wall and a chamber lower wall, each wall having an inner surface and an outer surface and defining a reaction space therebetween;
• a substrate support provided within said reaction space, said substrate support having a central axis around which said substrate support rotates;
• a plurality of forward ribs provided on the outer surface of at least one of the chamber upper wall and chamber lower wall that project a shadow in a portion upstream of the central axis of the reaction space;
• and
• a plurality of rearward ribs provided on the outer surface of at least one of the chamber upper wall and chamber lower wall that project a shadow in a portion downstream of the central axis of the reaction space;
• wherein at least some of the shadows of the forward ribs have a mirrored projection in the downstream portion of the reaction space that are approximately equidistant from adjacent rearward ribs, and at least some of the shadows of the rearward ribs have a mirrored projection in the upstream portion of the reaction space that are approximately equidistant from the adjacent forward ribs.