Energy transfer microwave plasma source

A modular wafer processing microwave energy plasma source, comprising:

• a metal cylinder with top and bottom open ends fitted to a top lid and a bottom cover each with a centrally located port hole;
• a plasma tube disposed along the central axis of the cylinder with a gas inlet disposed in said port hole in the top lid and a plasma outlet disposed in the port hole in the bottom cover;
• a pair of fan mounts on opposite exterior sides of the cylinder that provide for a pair of push-pull air fans to move an air flow into and out of the interior of the cylinder to cool the plasma tube;
• and
• an access and mount located in the cylinder wall for a microwave energy applicator with a ring type slow wave structure to surround the plasma tube;
• wherein, said microwave applicator provides for generating gas plasmas from microwave energy and comprises:
• a set of six equal-length parallel rods equally distributed at regular angular intervals of 60° in a circle;
• a top planar shorting ring perpendicularly connected to a top end of each and every one of the rods;
• a bottom planar shorting ring perpendicularly connected to a bottom end of each and every one of the rods;
• an upper and a lower planar feed ring that are each parallel to and positioned between the top and bottom planar shorting rings;
• telescoping means included in each of the rods that provides for adjusting the electrical distance between the top and bottom planar shorting rings and that provides for matching a resonant frequency of the applicator to an operating frequency of said microwave power source such that any impedance mismatch reflections can be minimized and any energy transferred to a plasma generated within said gas plasma tube can be maximized;
• and
• a tapered waveguide connected to feed opposite phases of microwave energy from said microwave power source to the upper and lower feed rings at a radial position intersected by any one of the rods;
• wherein, the planar shorting rings and planar feed rings are each provided with a coaxial hole to accommodate a gas plasma tube;
• wherein, the upper planar feed ring connects to odd numbered rods and the lower planar feed ring connects to even numbered rods;
• and
• wherein, the equal-length parallel rods are positioned such that adjacent rods are separated by about one half of the wavelength of operation of a microwave power source.