Integrated pressure and flow ratio control system

A pressure and flow ratio control system comprising:

• a plurality N of mass flow controllers MFCi (i=1, . . . , N) each configured to receive at an inlet an i-th one of a plurality N of fluids Fi (i=1, . . . , N) and to control flow rate of the i-th fluid Fi from the inlet through an outlet of the MFCi and onto a processing chamber configured to process the fluids Fi (i=1, . . . , N), the mass flow controllers including one master MFC and N-1 slave MFCs;
• wherein the master MFC is configured to receive from a host controller a pressure set point and a plurality N of flow ratio set points, the master MFC further configured to determine flow ratio set points for each of the N-1 slave MFCs and to communicate said flow ratio set points to the N-1 slave MFCs;
• and
• wherein the N-1 slave MFCs are configured to control the flow rates of the respective fluids Qi so as to maintain ratios Qi/QT (i=1, . . . , N) at the flow ratio set points received from the master MFC, where Qi represents flow rate of the i-th fluid Fi, and QT represents a sum QT=Q1+ . . . +Qi+ . . . QN of flow rates of all N individual fluids Fi (i=1, . . . , N).

A gas processing system comprising:

• a chamber configured to process a plurality of fluids Fi (i=1, . . . , N);
• and
• a plurality N of mass flow controllers MFCi (i=1, . . . , N) each configured to receive at an inlet an i-th one of the plurality of fluids Fi (i=1, . . . , N) and to control flow rate of the i-th fluid Fi from the inlet through an outlet of the MFCi and onto the chamber, the N mass flow controllers MFCi (i=1, . . . , N) including one master MFC and a plurality (N-1) of slave MFCs;
• wherein the master MFC is configured to receive flow ratio set points from a host controller, and to communicate the flow ratio set points to all the slave MFCs together with one or more command signals, so as to control ratios Qi/QT (i=1, . . . , N) at the flow ratio set points, where Qi represents flow rate of the i-th fluid Fi, and QT represents a sum QT=Q1+ . . . +Qi+ . . . QN of flow rates of all N individual fluids Fi (i=1, . . . , N);
• and
• wherein one of the mass flow controllers MFCi (i=1, . . . , N) is a pressure control MFC configured to receive a pressure set point from the host controller and to control pressure in the chamber at the pressure set point.

A method of controlling pressure of a processing chamber and flow ratios of a plurality N of fluids Fi (i=1, . . . , N) to the processing chamber, the method comprising:

• connecting a plurality N of mass flow controllers MFCi (i=1, . . . , N) between one or more sources of a plurality N of fluids Fi (i=1, . . . , N) and a processing chamber that processes the N fluids Fi, wherein the plurality N of mass flow controllers MFCi (i=1, . . . , N) include one master MFC and a plurality (N-1) of slave MFCs;
• the master MFC and the slave MFCs maintaining ratios Qi/QT (i=1, . . . , N) at flow ratio set points received from a host controller, wherein Qi represents flow rate of i-th fluid Fi as measured by i-th mass flow controller MFCi during flow of Fi from the source through the MFCi into the processing chamber, and wherein QT represents a sum QT=Q1+ . . . +Qi+ . . . QN of flow rates of all N fluids Fi;
• and
• one of the mass flow controllers MFCi (i=1, . . . , N) maintaining pressure in the processing chamber at a pressure set point received from the host controller.