The SST 3250 is a high vacuum multi-atmosphere sealing furnace that has been designed for lid sealing on wafers of 150-200mm diameter. The system is fully operational at vacuum levels of 10E-07 Torr up to 12 psig with automatic selection and control of up to three process gasses. A closed-loop electronic pressure controller with integral capacitance manometer provides fine control of pressure and flow throughout the full operating range of the system.