Patent ID: 7822570
Filing Date: 2010-10-26
Classification: G01F,Y10T

Abstract:
1. A method for determining an actual gas flow rate in a reaction chamber of a plasma processing system, the method comprising: delivering gas by a gas flow delivery system controlled by a mass flow controller (MFC) to an orifice, said orifice being upstream from said reaction chamber; pressurizing said gas to create a choked flow condition within said orifice; measuring a set of upstream pressure values of said gas via a set of pressure sensors; and applying, using a programmed computing device, a calibration factor of a set of calibration factors to determine said actual flow rate, said calibration factor being a ratio of an average of said set of upstream pressure values to an average of a set of golden upstream pressure values, said golden upstream pressure values representing pressure values associated with an indicated flow rate, said indicated flow rate being a flow rate as indicated by said MFC.