Embodiments of the present disclosure generally provide various apparatus and methods for reducing particles in a semiconductor processing chamber. One embodiment of present disclosure provides a vacuum screen assembly disposed over a vacuum port to prevent particles generated by the vacuum pump from entering substrate processing regions. Another embodiment of the present disclosure provides a perforated chamber liner around a processing region of the substrate. Another embodiment of the present disclosure provides a gas distributing chamber liner for distributing a cleaning gas around the substrate support under the substrate supporting surface.