Gas-Distribution Plate

Gas distribution plates, injection rings, and manifolds are the specific hardware pieces that implement a showerhead's gas-delivery job at a finer level of detail — the plate sets the hole pattern gas actually passes through, the injection ring adds gas entry from the chamber's periphery, and the manifold routes multiple gas lines together before they ever reach the chamber.

The distribution plate's hole pattern is a direct uniformity lever, since the spatial pattern of where gas actually enters the chamber sets the spatial pattern of deposition or etch rate across the wafer below it. A plate with evenly spaced, identical holes produces a different flow profile than one with holes concentrated more densely toward the center or edge; engineers tune that hole pattern specifically to counteract known non-uniformities elsewhere in the process — a chamber that etches slightly faster at the edge might use a distribution plate with proportionally fewer edge holes to compensate.

Peripheral injection rings add a second gas-entry point specifically to give process engineers an additional, independent uniformity control beyond the center-fed showerhead alone. Feeding gas only from the center, as a standard showerhead does, inherently biases the spatial gas profile radially outward from that single entry point; adding a separate injection ring around the chamber's periphery introduces gas from the edge inward as well, letting engineers balance center and edge flow contributions independently rather than relying on the showerhead's hole pattern alone to achieve uniformity.

Gas distribution plates, injection rings, and manifolds together implement the fine spatial and compositional control that makes uniform deposition and etch possible, each adding a specific lever — hole pattern, injection location, or upstream gas mixing — to a gas-delivery system that has to get both composition and spatial distribution right simultaneously.