A semiconductor wafer processing substrate support assembly, comprises a substrate support platform having a centrally disposed recess, coupled to a base disposed above the centrally disposed recess, a plate disposed above the base, and a substrate support disposed above the plate. The substrate support assembly further comprises a plurality of o-rings having a plurality of lobes, wherein a first lobed o-ring of the plurality of lobed o-rings is disposed between the support platform and the base, a second lobed o-ring is disposed between the base and the plate, and a third lobed o-ring is disposed between the plate and the substrate support. Moreover, the plurality of lobed o-rings are utilized in the support assembly for reducing the number of o-rings required in the support assembly.