Method for plasma processing using magnetically enhanced plasma chemical vapor deposition

A method for developing a range of cathode sheath voltages in a plasma processing machine comprising:

• determining a cathode sheath voltage upper limit for a plasma processing machine;
• releasing a process gas proximate a cathode of said plasma processing machine, said cathode being provided with a surface adapted to support a wafer and having an axis which is substantially normal to at least a portion of said surface;
• applying radio-frequency power to said cathode to form a plasma from said gas and to develop a cathode sheath proximate said surface of said cathode, where said radio-frequency is chosen such that cathode sheath voltage is no higher than said upper limit;
• developing a magnetic field within said plasma having flux lines which are substantially parallel to said axis of said cathode proximate to said surface of said cathode;
• and
• varying the strength of said magnetic field to vary said cathode sheath voltage from a maximum no greater than said upper limit when said magnetic field strength is at a minimum to a cathode sheath voltage lower limit when said magnetic field strength is at a maximum.

A method for plasma processing a wafer within a chamber comprising:

• disposing a wafer proximate to a cathode within a processing chamber;
• releasing a process gas into said chamber;
• applying radio frequency power having a frequency in the range from about 50 megahertz to about 800 megahertz to said cathode sufficient to create a plasma within said chamber and to develop a cathode sheath proximate to said cathode;
• developing a magnetic field within said chamber having flux lines which are substantially perpendicular to a surface of said wafer;
• and
• varying the strength of said magnetic field until a desired cathode sheath voltage level is attained.