Methods and assemblies for gas flow ratio control

A method comprising:

• identifying, by a master controller, a flow ratio setpoint for at least one of a process gas flow or a carrier gas flow to a process chamber to a plurality of mass flow controllers, wherein each of the plurality of mass flow controllers are configured to flow at least one of a process gas or a carrier gas from a process gas supply and via a distribution manifold into a respective zone of the process chamber;
• determining, by the master controller, a flow setpoint for the at least one of the process gas flow or the carrier gas flow through each of the plurality of mass flow controllers based on the identified flow ratio setpoint;
• and
• controlling, by the master controller, the at least one of the process gas flow or the carrier gas flow through each of the plurality of mass flow controllers according to the determined flow setpoint for each of the mass flow controllers based on a back pressure reading of a back pressure of the distribution manifold, the back pressure reading provided by a back pressure sensor.

A master controller comprising:

• a set of one or more processors, wherein the set of one or more processors is to:
• identify a flow ratio setpoint for at least one of a process gas flow or a carrier gas flow to a process chamber to a plurality of mass flow controllers, wherein each of the plurality of mass flow controllers are configured to flow at least one of a process gas or a carrier gas from a process gas supply and via a distribution manifold into a respective zone of the process chamber;
• determine a flow setpoint for the at least one of the process gas flow or the carrier gas flow through each of the plurality of mass flow controllers based on the identified flow ratio setpoint;
• and
• control the at least one of the process gas flow or the carrier gas flow through each of the plurality of mass flow controllers according to the determined flow setpoint for each of the mass flow controllers based on a back pressure reading of a back pressure of the distribution manifold, the back pressure reading provided by a back pressure sensor.