Abstract: Embodiments of the present invention are directed to adjusting the spacing between the substrate support and the faceplate of the gas distribution member to achieve improved uniformity of the layer formed on the substrate. One embodiment of the present invention is directed to a method of adjusting a spacing between a gas distribution member and a substrate support disposed generally opposite from the gas distribution member, wherein the substrate support is configured to support a substrate on which to form a layer with improved thickness uniformity. The method comprises forming a layer on the substrate disposed on the substrate support; measuring a thickness of the layer on the substrate; and calculating differences in thickness between a reference location on the substrate and a plurality of remaining locations on the substrate.