A method for controlling a process on a substrate. The method comprising: providing the substrate, the substrate having an upper surface, an opposite lower surface and an edge between the upper and lower surfaces; processing the upper surface of the substrate with a first fluid; directing a second fluid against a portion of the lower surface proximate to the edge of the substrate, wherein the second fluid flows adjacent to the edge of the substrate; and controlling the temperature of the second fluid in order to affect a processing of an edge region of the upper side of the substrate.