Abstract: An assembly for holding a substrate in a chemical mechanical planarization (CMP) apparatus is provided. The assembly includes a holder frame insertable into the chemical mechanical planarization apparatus, the holder frame having an inner wall. The assembly further includes at least one rolling mechanism rotatably mounted in the holder frame such that at least a portion of the rolling mechanism protrudes from the inner wall. The assembly also includes a wafer chuck movably mounted in the holder frame, the wafer chuck having a first side shaped to substantially conform to the inner wall and to be in continuous contact with the at least one rolling mechanism during planarization, and a second side adapted to receive a substrate for planarization. Also provided are an improved assembly for holding a substrate in a CMP apparatus and a method for reducing friction in a gimbaling mechanism of a wafer chuck in a wafer holder in a CMP apparatus during planarization.