Generally, only the front end of each piece of process equipment sticks into the cleanroom space. The rest of the unit sits in a utility room where a complex system of pipes delivers ultra pure water, gases, and chemicals to it. This room also contains electrical equipment and diagnostic tools that monitor the operation and maintenance needs of the oxidation equipment.
With this arrangement, the wafers can be kept ultraclean while, in the utility room, technicians are free to perform the "dirtier" operations of maintaining and supplying the process equipment.
