C. Lai et al., MAGNETICALLY CONFINED INDUCTIVELY-COUPLED PLASMA-ETCHING REACTOR, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 13(4), 1995, pp. 2086-2092
Citations number
27
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
A planar radio frequency (rf) inductively coupled plasma etching syste
m has been constructed. The plasma is confined by an external multidip
ole magnetic bucket made of Nd-Fe-B magnets. This magnetically confine
d inductively coupled plasma system is equipped with a helium backside
-cooled electrostatic wafer chuck and a loadlock chamber. A single-sid
ed planar Langmuir probe was used to map electron velocity distributio
n functions (EVDFs) radially and axially for both Ar and N-2 plasmas w
ith rf power up to 1 kW at low pressure (2 mTorr). By rotating the sin
gle-sided probe, the authors found that the EVDFs are noticeably aniso
tropic. The values of the plasma potential, which were highly uniform
radially, were independent of the probe orientation, but those of the
floating potential depended strongly on it. The radial uniformity and
the absolute magnitude of the plasma potential are confirmed by measur
ements using an emissive probe. The Langmuir probe measurements showed
some deviations from Maxwellian EVDFs for both Ar and N-2 plasmas. Be
cause of the multidipole confinement the plasma densities are quite un
iform axially, and the radial uniformity improves as the axial distanc
e from the quartz window increases. The rf plasma potential fluctuatio
ns were also measured, using a capacitive probe. (C) 1995 American Vac
uum Society.