Plasma chamber with a multiphase rotating cross-flow with uniformity tuning

A plasma treatment chamber, comprising:

• one or more sidewalls;
• a support within the one or more sidewalls to hold a workpiece;
• an array of individual gas injectors distributed about a periphery of the one or more sidewalls;
• one or more pump ports along the one or more sidewalls to eject gas from the plasma treatment chamber;
• and
• a controller configured to control the plasma treatment chamber during an etch application, wherein an etch rate uniformity of a material on the workpiece is tuned or controlled by:
• using the array of individual gas injectors to inject a gas flow in a direction generally parallel to and across a surface of the workpiece;
• and
• prior to or during gas flow injection, changing the gas flow injection angle across the workpiece by selecting between a wide set of adjacent ones of the individual gas injectors and a narrow set of adjacent ones of the individual gas injectors, wherein selecting the narrow set of adjacent ones of the individual gas injectors decreases the gas injection angle.

A method of controlling etch rate uniformity of a material on the workpiece in a plasma treatment chamber, the method comprising:

• injecting, from a first set of adjacent ones of the individual gas injectors, a first gas flow in a direction generally parallel to and across a surface of the workpiece to etch materials on the workpiece;
• and
• simultaneously injecting, from at least a portion of a remaining set of the individual gas injectors, a second gas flow in a direction generally parallel to and across a surface of the workpiece, wherein the second gas flow is used to i) dilute the first gas flow to reduce an area on the workpiece having a faster etch rate;
• or ii) act as an additional etchant to increase the etch rate in the area of the workpiece having the faster etch rate.