There is disclosed a substrate holding apparatus comprising: (a) a member comprised of a top surface, a bottom surface, a center region and a plurality of segments disposed around and integral with the center region, the segments being defined by a plurality of slits in the member, wherein the segments bend and overlap when subjected to a compressive force, thereby decreasing the width of the member, and wherein the extent of bending and overlapping of the segments spontaneously decreases when the compressive force lessens, thereby increasing the width of the member; and (b) compressive force mechanism operatively associated with the member for controlling the amount of compressive force on the member.