Abstract: A self-contained modular processing apparatus is disclosed for processing workpieces, and in particular, silicon wafers. The apparatus is constructed of framed modules which plug into a service facility docking subassembly and interlock therewith to make up a complete modular processing system for wafer processing. Each module may be provided with its own wafer transporting mechanism and includes a built-in CPU such that each module is an independent, stand-alone processing unit. Each processing unit, by being capable of independent operation, functions as a building block to configure a modular processing system capable of handling wafer flow in multiple directions while performing a multitude of processing functions or operations. Individual modules are arranged along a line of single fold symmetry such that a single transport mechanism may be employed for transferring wafers among adjacent modules.