Properties of a microwave-enhanced magnetron plasma excited by electron cyclotron resonance

Abstract

A sputtering source utilizing both electron cyclotron resonance microwave and DC planar magnetron plasmas is described. This is achieved by introducing microwave power into the plasma by a co-axial-type cavity. The magnetron cathode is placed on the open end of the inner conductor. The microwave propagation from the surface of the plasma column produces additional gas ionization, resulting in a denser plasma at a constant target voltage. The operation pressure of this source is a hundredth that of a conventional magnetron source. It was found that the plasma density near the substrate increases with increasing microwave power during sputtering. Adjustment of the microwave power results in a controlled DC bias potential being developed at the substrate surface. The deposition rate of Cu is more than for an argon gas pressure of Torr, and microwave and DC powers of 500 and 200 W respectively. The measured deposition uniformity is 4.5% within a 10 cm diameter for a 15 cm diameter target.