Processes live or die by the repeatability of the process conditions. It is not enough that a particular tool perform in a consistent manner, run-to-run and day-to-day, but also multiple tools that are running the same process must run that process in the same manner and under the same conditions. From a vacuum and gas control standpoint, that means identical flows and pressures.
Process pressure and flow measurement instruments are individually calibrated and are guaranteed to meet specific accuracy requirements.Calibration intervals for these instruments are usually on the order of one year.
