Abstract: An arc shaped exhaust baffle having two ends that define a gap therebetween that is not directly accessible by the exhaust plenum, that provides improved process gas flow distribution in a semiconductor process chamber, has a plurality of apertures formed therethrough and distributed about a baffle circumference. The apertures communicate with an underlying exhaust plenum to generate a uniform gas flow across the substrate surface during substrate processing. The exhaust baffle has at least one offset passage formed therethrough that may be adapted to draw process gas across a substrate surface at an acute angle relative thereto from the gap, and thereby provide an exhaust pattern that influences the process gas flow about the entire circumference of the substrate.