A conditioning apparatus for use in a CMP system is provided along with an associated method of operation. The conditioning apparatus includes rotation mechanics and oscillation mechanics. The rotation mechanics are capable of rotating a shaft which causes a holder and a conditioning substrate to be rotated. The oscillation mechanics are capable of moving a position of the shaft within a region defined by a peripheral boundary that is less than and within an outer periphery of the conditioning substrate. A conditioning substrate backing is also included in the conditioning apparatus. The conditioning substrate backing defines a differential pressure distribution that is capable of being applied to the conditioning substrate.