Ak. Quick et al., ETCH RATE AND PLASMA-DENSITY RADIAL UNIFORMITY MEASUREMENTS IN A CUSPED FIELD HELICON PLASMA ETCHER, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 14(3), 1996, pp. 1041-1045
Citations number
7
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
Experiments on the University of Wisconsin helicon etcher were conduct
ed to study the effects on uniformity of applying a cusped magnetic fi
eld to the etching chamber. Also a comparison was made between long an
d short antenna/substrate separation distances. The plasma radial dens
ity uniformities, measured using a Langmuir probe over the inner 10 cm
diameter of the chamber, gave maximum density variations of +/- 22% w
ith the cusp off and +/- 1.28% at the zero field region of the cusp. T
he maximum SiO2 etch rate in CF4/Ar plasmas occurred at 50% Ar concent
ration in the long source configuration. Etch rate uniformity of SiO2
etching in a CF4/Ar/O-2 plasma improved from +/- 8.1% to +/- 2.6% for
a 82.5 mm wafer by shortening the antenna-substrate separation distanc
e from 108 to 47 cm. Azimuthal asymmetry of the plasma produced from t
he Nagoya type III antenna was observed in the shea source configurati
on in which the SiO2 etch rate uniformity varied from +/- 1.5% across
the vertical axis of a 150-mm-diam wafer to +/- 12% across the horizon
tal axis of the wafer. (C) 1996 American Vacuum Society.