Embodiments generally provide an apparatus and method for processing substrates using a multi-chamber processing system (e.g., a cluster tool) that has an increased system throughput, increased system reliability, substrates processed in the cluster tool have a more repeatable wafer history. In one embodiment, non-orthogonal robot trajectories are used to assure reliable and high speed substrate transfer. In another embodiment, at least one buffering station is used to avoid collision and improve throughput. In another embodiment, optimal positioning of the robots are used to improve throughput.