Low-gas-pressure sputtering by means of microwave-enhanced magnetron plasma excited by electron cyclotron resonance

A sputtering source utilizing both electron cyclotron resonance (ECR) microwave and dc planar magnetron plasmas is described. Microwave power is introduced into the plasma by a coaxial-type cavity. The magnetron cathode is placed on the open end of the inner conductor. The ECR magnetic field is applied in the open end by magnetron configuration magnets. The microwave propagation from the surface of the plasma column produces additional gas ionization resulting in a denser plasma at constant voltage. The operation pressure of this source is one-hundredth as low as that of a conventional magnetron source. The deposition rate of Cu is more than 130 nm/min for an argon gas pressure of 8×10−5 Torr, and microwave and dc powers of 500 and 200 W, respectively. Measured deposition uniformity is ±4.5% within a 10 cm diam for a 15-cm diam target.