Method of operating a dual chamber reactor with neutral density decoupled from ion density

A method of operating a plasma etch reactor having a main chamber for containing a process gas and for holding a semiconductor wafer to be etch processed, a bias power applicator for applying RF bias power to the wafer and a main plasma source power applicator for applying main chamber plasma source power to the main chamber, and a secondary chamber capable of forming, from a secondary chamber process gas, neutral species furnished to said main chamber, and a second plasma source power applicator for applying secondary chamber plasma source power to said secondary chamber, said method comprising:

• applying main chamber plasma source power to said process gases in said main chamber by said main plasma source power application to produce a first plasma in said main chamber;
• applying secondary chamber plasma source power to said process gases in said secondary chamber by said second plasma source power applicator to produce a second plasma in said secondary chamber;
• applying RF bias power to the wafer by said bias power applicator;
• selecting a range of etch rates at which said wafer is to be etch processed, said range of etch rates corresponding to a large range of main chamber plasma source power in the absence of secondary chamber plasma source power;
• operating said main chamber source power within a compressed range corresponding to the bottom of said large range and corresponding to a diminished etch rate in the absence of said secondary chamber plasma source power;
• preventing charged particles formed in the secondary chamber from entering the main chamber by interposing a charged particle filter between the main and secondary chambers, whereby said secondary chamber is primarily a neutral species source to said main chamber for independent control of ion and neutral species densities in said main chamber;
• and
• raising said secondary chamber source power to an increased level sufficient to raise said etch rate into the range of etch rates selected in the step of selecting.

A method of performing a plasma enhanced chemical vapor deposition process in a reactor having a main chamber for containing a process gas and for holding a semiconductor wafer to be etch processed, a bias power applicator for applying RF bias power to the wafer and a main power applicator for applying main chamber source power to the main chamber, and a secondary chamber capable of forming, from a secondary chamber process gas, neutral species furnished to said main chamber, and a second power applicator for applying secondary chamber source power to said secondary chamber, said method comprising:

• applying main chamber plasma source power to said process gases in said main chamber by said main plasma source power applicator to produce a first plasma in said main chamber;
• applying secondary chamber plasma source power to said process gases in said secondary chamber by said second plasma source power applicator to produce a second plasma in said secondary chamber
• applying RF bias power to the wafer by said bias power applicator;
• selecting a range of deposition rates at which said wafer is to be processed, said range of deposition rates corresponding to a large range of main chamber source power in the absence of secondary chamber source power;
• operating said main chamber source power within a compressed range corresponding to the bottom of said large range and corresponding to a diminished deposition rate in the absence of said secondary chamber source power;
• preventing charged particles formed in the secondary chamber from entering the main chamber by interposing a charged particle filter between the main and secondary chambers, whereby said secondary chamber is primarily a neutral species source to said main chamber for independent control of ion and neutral species densities in said main chamber;
• and
• raising said secondary chamber source power to an increased level sufficient to raise said deposition rate into the range of deposition rates selected in the selecting step.

A method of operating a plasma reactor having a main chamber for containing a process gas and for holding a semiconductor wafer to be processed, a bias power applicator for applying RF bias power to the wafer and a main plasma source power applicator for applying main chamber source power to the main chamber, and a secondary chamber capable of forming, from a secondary chamber process gas, neutral species furnished to said main chamber, and a second plasma source power applicator for applying secondary chamber source power to said secondary chamber, said method comprising:

• applying main chamber plasma source power to said process gases in said main chamber by said main plasma source power applicator to produce a first plasma in said main chamber;
• applying secondary chamber plasma source power to said process gases in said secondary chamber by said second plasma source power applicator to produce a second plasma in said secondary chamber;
• applying RF bias power to the wafer by said bias power applicator;
• selecting a secondary chamber source power level;
• and
• determining an upper limit of said main chamber source power level below which said secondary chamber source power level results in at least said desired increase in neutral species density in said main chamber;
• preventing charged particles formed in the secondary chamber from entering the main chamber by interposing a charged particle filter between the main and secondary chambers, whereby said secondary chamber is primarily a neutral species source to said main chamber for independent control of ion and neutral species densities in said main chamber;
• and
• maintaining the main chamber source power level below said upper limit so as to enhance an increase in the neutral species density in said main chamber in response to an increase in said secondary chamber source power level.