A lithographic projection apparatus includes a beam production system to provide a beam of radiation, pattern the beam of radiation, and project the patterned beam onto a target portion of a substrate, a support table including protrusions to support an article, a detector to detect height deviations of the protrusions, a material removing device arranged to modify a height of the protrusion material, a controller coupled between the detector and the material removing device, wherein material removing device includes a removal tool selected from the group consisting of a mechanical polishing device, a magneto rheological finishing tool, and a single or multipoint diamond tool.