A substrate support pedestal comprises an electrostatic chuck, a cooling base, a gas flow passage, a porous plug, and a sealing member. The electrostatic chuck comprises body having a cavity. The cooling base is coupled to the electrostatic chuck via a bond layer. The gas flow passage is formed between a top surface of the electrostatic chuck and a bottom surface of the cooling base. The gas flow passage further comprises the cavity. The porous plug is positioned within the cavity to control the flow of gas through the gas flow passage. The sealing member is positioned in a groove formed in the cooling base and configured to form a seal between the cooling base and one or both of the porous plug and the body of the electrostatic chuck.