An apparatus for supporting a substrate is described that has a ball adapted
to
minimize damage between the substrate support and the substrate supported thereon.
In one embodiment, an apparatus for supporting a substrate includes ball disposed
on an inclined ball support surface. The ball support surface is adapted to bias
the ball toward one side of the ball support surface thereby providing space for
the ball to roll as the substrate supported thereon changes in length when exposed
to thermal influences. In another embodiment, the apparatus further comprises a
cage adapted to capture the ball to the ball support surface.
