Plasma processing apparatus and method

A plasma processing apparatus for processing a product using plasma, comprising:

• a high-frequency power source for applying bias power to an electrode on which a substrate to be processed is disposed;
• an insulating layer formed on a surface of said electrode on which said substrate to be process is disposed;
• a conductive material buried within one portion of said insulating layer in a ring-like form;
• a feeder line connecting said high-frequency power source and said conductive material;
• a variable capacitor provided in said feeder line;
• and
• a direct current power source connected to said electrode at a position between said electrode and said high-frequency power source;
• wherein said one portion of said insulating layer where said conductive material is buried within and surrounded by said insulating layer formed on an outer part of said electrode and has a thickness which is greater than a substantially constant thickness of another portion of said insulating layer where said conductive material is not buried, said another portion of substantially constant thickness of said insulating layer being formed on said electrode and extending at least from a central part of said electrode to said one portion of said insulating layer where said conductive material is buried, and said one portion of said insulating layer being formed in an area opposite to a plasma main generating area of the plasma processing apparatus, said plasma main generating area being distributed in a doughnut shape so as to reduce a bias impedance at positions within a surface of said substrate which are opposite to said plasma main generating area;
• and
• wherein a power introducing window is provided opposite to said electrode to enable production of said plasma between said power introducing window and said electrode, and a coil having plural windings is disposed on said power introducing window, said plural windings having unequal spaces between at least two of the coil windings so as to enable production of said plasma in said plasma main generating area.