Plasma process device

A plasma processing apparatus comprising:

• a processing chamber for performing plasma-assisted processing;
• microwave introducing means having an interior space in which a first standing wave of a microwave is formed by means of resonance, the microwave introducing means directing the microwave to said processing chamber;
• a dielectric provided between said processing chamber and said microwave introducing means and adjacent said interior space for directing the microwave into said processing chamber, a second standing wave of the microwave being formed within the dielectric by means of resonance;
• and
• a slot antenna having an aperture through which the microwave is passed from said interior space to said dielectric, the slot antenna covering a side of said dielectric that faces said interior space, wherein
• said aperture is generally located at a point where the position of a loop in the first standing wave orthogonally projected to said slot antenna coincides with the position of a loop in the second standing wave orthogonally projected to said slot antenna.