Electromagnetic modeling of microwave and RF plasma sources

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Summary form only given, as follows. Low-pressure/high-density and moderate-pressure plasma sources are finding increased use in a variety of materials processing applications. Several design variations have been developed using microwave and RF excitation of the plasma discharges. The modeling of these sources requires the solution of the electromagnetic fields, plasma discharge physics and chemistry, and plasma-surface interactions. This paper focuses on the self-consistent solution of the electromagnetic fields and plasma discharge physics in microwave and RF plasma sources. Two techniques used for the electromagnetic field solutions are: (1) the finite-difference time-domain (FDTD) solution of Maxwell's equations and (2) the finite-difference solution of the vector Helmholtz equation. Implementations of both solution techniques for the solution of a variety of plasma sources have been developed. Specific sources modeled include unmagnetized microwave plasma sources, multipolar permanent magnet ECR plasma sources, divergent field ECR plasma sources, and RF inductively coupled plasma sources. The electromagnetic fields are solved by the two techniques in both two or three dimensions. The methods for coupling of the electromagnetic solutions to the plasma discharge behavior using both particle and fluid descriptions have also been investigated and will be reported on. This paper will discuss the strengths and weaknesses of each of the two methods for solving the electromagnetic fields in rf and microwave plasma sources. Examples will be, presented of the modeled power absorption profiles, electric field strengths, and plasma uniformities in a variety of plasma sources.