Abstract: Apparatus for processing a substrate are described herein. More specifically, embodiments described herein relate to separate pre-clean process modules and pre-clean control modules coupled to a cluster tool assembly. Each pre-clean process module and each pre-clean control module are connected by a cable conduit which is configured to have power and control cables passing therethrough between the pre-clean process module and the ore-clean control module. A maintenance passage is formed through the cluster tool assembly. Each of a purge gas source, a process gas source, a manometer, an isolation port, and a throttle valve are all accessible from one side of the pre-clean process module.