Green mode: Equipment interface to reduce semiconductor sub-fab utility consumption

Traditionally, process tool sub-fab systems, for example vacuum pumps and gas abatement systems, are designed to reliably serve the most challenging semiconductor production manufacturing applications 24 hours a day and seven days a week. However, it is never the case that 100% of the wafer processing tools in any semiconductor fab are in use 100% of the time. Communicating the actual status of the associated process tool to the sub-fab systems, and providing a look-ahead indication of the planned production, can allow sub-fab systems to be put into a Green Mode idle state at times when the production equipment does not require maximum performance from the sub-fab systems. This Green Mode can potentially save 10 to 40% of the sub-fab systems' utility costs, depending on the facility operations. For vacuum and exhaust gas management systems, entering Green Mode results in reductions in electrical power, process nitrogen, process cooling water, and heat loading, along with decreases in effluent discharges to wastewater treatment plants. The savings realized from Green Mode operation are not only good for the environment, but they also result in a direct reduction in fab operating expenses. We report here initial data collected putting Green Mode concepts into practice at a GLOBALFOUNDRIES production wafer fab, using plasma etch tools as the lead vehicles. This project is a productive collaboration between sub-fab tool suppliers, semiconductor process tool manufacturers, and GLOBALFOUNDRIES. We show that the savings we expected to incur by implementing Green Mode are both real for the fab and good for the environment.