Techniques of swapping two samples with a mechanical arm that has no backlash, no friction, no particle contamination are described. With the unique structure and the material used for the cables, the mechanical arm provides considerable operating life. When used in a semiconductor inspection system, the mechanical arm, also referred to herein a cable drive robot mechanism, can be advantageously used to swap two wafers as part or within the inspection system. The two wafers, one examined and the other one yet to be examined, can be swapped between two chambers. During the exchanging process, the cable drive robot mechanism seamlessly picks up an examined wafer to exit one chamber while loading up an unexamined wafer to enter another chamber at the same time.