Abstract
When the pump-down time by the dry vacuum pump is predicted, the performance curve (inlet pressure vs. pumping performance), which is measured prior to the pump-down time calculation, is used for calculation. However, the potential performance fluctuation might not be figured out from the performance curve, because the gas flow rate flown into the pump dynamically changes during the chamber pump-down from atmospheric pressure. This activity is for the accuracy improvement of chamber pump-down time prediction with the assumed dynamic performance fluctuation.
