Patent ID: 8216420

Claim:
A plasma processing apparatus, comprising: a processing chamber having a vacuum, a gas being supplied to said processing chamber; a support electrode provided inside said processing chamber and supporting a processing-target object; an introduction window disposed on an upper side of the processing chamber through which a μ-wave is introduced into the processing chamber; a cavity unit disposed above the introduction window such that a bottom surface thereof contacts the introduction window; a circular waveguide connected to an upper surface of the cavity unit and extending substantially vertically, the circular waveguide being configured to propagate the μ-wave into the cavity unit and toward the introduction window; a reflection suppressor coupled to the circular waveguide for suppressing a reflective wave propagated upward into the circular waveguide, the reflection suppressor comprising a chamber having a larger diameter than that of the circular waveguide; a tuning box disposed above and connected to said reflection suppressor; and two μ-wave waveguides connected to said tuning box and disposed such that each of the two p-wave waveguides have axes that are on a flat plane which is substantially parallel to said tuning box or perpendicular to an axis of said waveguide and are set with an angle of substantially 90° therebetween, said two μ-wave waveguides introducing said μ-waves which are set a phase difference therebetween of substantially 90° in respective electric fields from said two directions to said tuning box, wherein said tuning box superimposes said respective μ-wave and generates a circularly polarized wave in a predetermined mode that is propagated inside the circular waveguide toward the introduction window.