Gas supply unit and substrate processing apparatus including gas supply unit

A gas supply unit, comprising:

• an upper plate provided with a plurality of injection holes, the plurality of injection holes comprising a center injection hole and a plurality of outer injection holes;
• a divider plate constructed and arranged against the upper plate to guide a flow of gas from the injection holes;
• a first gas line fluidly coupled to the center injection hole;
• and a plurality of second gas lines fluidly coupled to the plurality of outer injection holes;
• wherein the plurality of outer injection holes is arranged concentrically around the center injection hole;
• and wherein the divider plate is provided with a center through hole fluidly communicating with the center injection hole and is provided with a plurality of protrusions extending towards the upper plate and extending from the center through hole to a perimeter of the divider plate thereby creating a plurality of zones, each of the zones fluidly communicating with one of the outer injection holes, and wherein each of the plurality of zones extends from the center through hole to the perimeter of the divider plate;
• and wherein the center through hole is configured to receive a gas from the center injection hole and to provide the gas through a shower plate.