System, method and apparatus for plasma etch having independent control of ion generation and dissociation of process gas

A system for generating an etching species comprising:

• a source gas mixture source;
• an etchant gas source;
• a process chamber including:
• a top electrode including:
• a plurality of hollow cathode cavities the source gas mixture source coupled to an inlet of each one of the plurality of hollow cathode cavities;
• a first biasing signal source coupled to each one of the plurality of hollow cathode cavities;
• a corresponding outlet for each one of the plurality of hollow cathode cavities, the corresponding outlets opening to a wafer processing region in the process chamber, the wafer processing region being located between the outlets of each of the plurality of hollow cathode cavities and a surface to be etched;
• and
• a plurality of injection ports coupled to the etchant gas source, the plurality of injection ports capable of injecting the etchant gas into the wafer processing region;
• a bottom electrode for supporting a semiconductor wafer, the semiconductor wafer including the surface to be etched.

A method of etching a semiconductor wafer comprising:

• injecting a source gas mixture into a process chamber including:
• injecting the source gas mixture into a plurality of hollow cathode cavities in a top electrode of the process chamber;
• generating a plasma in each one of the plurality of hollow cathode cavities including applying a first biasing signal to the plurality of hollow cathode cavities;
• producing activated species in the hollow cathode cavities;
• and
• outputting the produced activated species from corresponding outlets of each of the plurality of hollow cathode cavities into a wafer processing region in the process chamber, the wafer processing region being located between the outlets of each of the plurality of hollow cathode cavities and a surface to be etched;
• injecting a etchant gas mixture into the wafer processing region, the etchant gas mixture being injected through a plurality of injection ports in the top electrode such that the etchant gas mixture mixes with the activated species output from the outlets of the plurality of hollow cathode cavities including:
• generating a plasma in the wafer processing region;
• and
• generating a desired chemical species in the wafer processing region and wherein the etchant gas mixture is substantially prevented from flowing into the outlets of each of the plurality of hollow cathode cavities by the activated species flowing from the outlets of each of the plurality of hollow cathode cavities, wherein the outlet for each one of the plurality of hollow cathode cavities as a width of less than twice a plasma sheath thickness;
• and
• etching the surface to be etched.