E. Kusano et al., Effect of coil-dc potential on ion energy distribution measured by an energy-resolved mass spectrometer in ionized physical vapor deposition, J VAC SCI A, 17(4), 1999, pp. 2360-2363
Energy distribution of Ar+ and Ti+ ions land plasma conditions have been in
vestigated for various de potentials of the rf inductive coil in ionized ph
ysical vapor deposition. The sputtering cathode used in the experiment is a
conventional magnetron sputtering source with a Ti target (55 mm phi) whic
h is coupled with a rf coil (60 mm phi, made of Cu). The mass spectrometer
used to measure ion energy distributions is an energy-resolved type plasma
monitor. The coil de potential is controlled by changing the resistance of
the resistor in the termination inductance-capacitance-resistance (LCR) cir
cuit connecting the coil to the ground. By increasing the resistance of the
LCR circuit, the peak of the Ar+ energy spectra shifts to a lower energy.
In addition it is found by the probe measurements that the plasma potential
decreases with increasing the termination resistance. The changes in the p
eak energy in the ion energy spectra show a good agreement with the change
in the plasma potential; as a result of the change in the plasma potential,
the energy distribution of ions;; accelerated toward the grounded substrat
e by the sheath shifts-to a lower energy in accord with a plasma potential
change. In this experiment, plasma potential is strongly affected by the dc
self bias of the rf inductive coil induced by a current flow from the grou
nd to the coil through the termination resistance because in the apparatus
used the coil was placed inside the chamber. (C) 1999 American Vacuum Socie
ty [S0734-2101(99)05404-4].