A semiconductor processing system is described. The system includes a processing chamber having an interior capable of holding an internal chamber pressure below ambient atmospheric pressure. The system also includes a pumping system coupled to the chamber and adapted to remove material from the processing chamber. The system further includes a substrate support pedestal, where the substrate support pedestal is rigidly coupled to a substrate support shaft extending through a wall of the processing chamber. A bracket located outside the processing chamber is provided which is rigidly and sometimes rotatably coupled to the substrate support shaft. A motor coupled to the bracket can be actuated to vertically translate the substrate support pedestal, shaft and bracket from a first position to a second position closer to a processing plate. A piston mounted on an end of the bracket provides a counter-balancing force to a tilting force, where the tilting force is generated by a change in the internal chamber pressure and causes a deflection in the position of the bracket and the substrate support. The counter-balancing force reduces the deflection of the bracket and the substrate support.