Apparatus for generating etchants for remote plasma processes

An apparatus for providing a remote plasma source (RPS) for generating etchants, comprising:

• an upper electrode with a first hollow cavity configured to induce a hollow cathode effect within the first hollow cavity;
• a lower electrode with a second hollow cavity configured to induce a hollow cathode effect within the second hollow cavity, wherein the first hollow cavity and the second hollow cavity are symmetrical;
• a first gap positioned between and electrically separating the upper electrode and the lower electrode;
• and
• an annular dielectric cover in direct contact with the lower electrode in the first gap and forms a second gap between an uppermost surface of the annular dielectric cover and a lowermost surface of the upper electrode, wherein the annular dielectric cover fills approximately 50% to approximately 95% of a height of the first gap, wherein the annular dielectric cover has an inner diameter smaller than an outer edge of an opening of the second hollow cavity which extends, at least partially, into the opening while directly in contact with a surface of the second hollow cavity, and wherein capillary holes are spaced in proximity of an innermost edge of the annular dielectric cover and have a diameter of less than two times a thickness of a sheath of plasma to be generated with the RPS.