Generally, a method and apparatus for retaining a substrate is provided. In one embodiment, a carrier for retaining a substrate comprises a carrier plate having a lower surface, at least one first fluid outlet and a second fluid outlet. The first fluid outlet is fluidly coupled to the lower surface of the carrier plate. The second fluid outlet is fluidly coupled to the lower surface of the carrier plate. A first fluid circuit is coupled to the first fluid outlet and is adapted to flow a fluid forms a fluidic layer between the carrier plate and the substrate. A second fluid circuit is coupled to the second fluid outlet and is separate from the first fluid circuit.