A support table having: a base surface configured to be substantially parallel to a lower surface of a substrate, a plurality of burls each having a respective distal end and a first height above the base surface, the burls arranged to support the substrate by the respective distal ends, and a plurality of elongate raised protrusions protruding above the base surface, each elongate raised protrusion having a second height above the base surface that is less than the first height. The base surface has a plurality of regions within each of which some of the elongate raised protrusions are located. All of the elongate raised protrusions located within each region have substantially the same direction of elongation such that they are substantially parallel to each other so as to form between the elongate raised protrusions at least one gas flow path substantially parallel to the elongate raised protrusions.