Plasma production using rotating mode radial line slot antennas with densely arrayed slots

It is significantly important for achieving large-scaled material processing to product large-area and uniform plasma. In particular, with the progress of memory sizes of microprocessors, the uniformity of plasma parameters over large-area is an essential problem for a high speed and high quality process. On the other hand, it is also desirable to be able to control the plasma radial profiles directly only by the antenna parameters as the need arises from the kinds of process. A radial line slot antenna (RLSA) with densely arrayed slots has already been proposed for a plasma processing system and the basic characteristics were confirmed. In our previous work, however, illuminations of locally excited plasma were observed and improvement of the uniformity is urgently required. In this paper, a novel feeding structure using the TE₁₁ rotating mode in an RLSA for plasma production is proposed. Moreover, novel slot patterns with different slot coupling distribution are fabricated and tested. The plasma measurement is performed at 2.45 GHz with a power of 1.0-3.0 kW through a quartz glass window into the discharge chamber filled with argon at a pressure of 30 mtorr. An extremely uniform plasma over a large diameter is observed and the possibility of control of the plasma distribution in the radial direction by changing the slot coupling is verified