Process chambers for substrate vacuum processing tool

A substrate processing apparatus is described. The apparatus includes a substrate load lock chamber. A substrate transfer chamber is vacuum coupled to the substrate load lock chamber. A plurality of process chamber modules are vacuum coupled to the substrate transfer chamber. At least two of the process chamber modules are horizontally clustered around the substrate transfer chamber. In addition, at least two of the process chamber modules are vertically arranged with one process chamber module above the other process chamber module. The substrate transfer chamber includes one or more robotic arms for transferring semiconductor substrates between the substrate load lock chamber and the plurality of process chamber modules.