Browse Prior Art Database

Enhanced RF Induction Plasma Production Using Thin Coils

IP.com Disclosure Number: IPCOM000105065D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Guarnieri, CR: AUTHOR [+3]

Abstract

Disclosed is a device for generation of high density plasma by RF induction using a thin, spiral-like coil. The thin cross-section of the coil increases the RF current density in the vicinity of the plasma thus increasing the density of the electrons, ions, and radicals in the plasma. The use of the thin cross-section coil in RF induction plasma gener- ation therefore leads to faster processing rates.

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Enhanced RF Induction Plasma Production Using Thin Coils

      Disclosed  is a device for generation of high density plasma by
RF induction using a thin, spiral-like coil.    The  thin
cross-section  of  the coil increases the RF current density in the
vicinity of the plasma thus increasing the density of the electrons,
ions, and radicals in the plasma.  The use of the thin cross-section
coil in RF  induction  plasma  gener- ation therefore leads to faster
processing rates.

      Prior art [1,2]  describes a spiral-like coil positioned
adjacent to a low pressure vessel and separated from the vessel by a
planar dielectric window.   Radio  frequency currents  in  the  coil
induce currents in the plasma which forms on the low-pressure side of
the window.

      It is well-known that RF currents only flow on the  surfaces of
good conductors.   At 13.56 MHz the depth of penetration of RF
currents in copper is approximately 20 microns.   Thus the thick
cross-section RF coils described in [1,2,] are not necessary.  In
fact, by using thin cross-section coils  the  RF  surface currents
become  physically closer to the plasma.  This im- proves plasma
production efficiency.

      To demonstrate the improvement of plasma generation using  a
thinner  coil,  polyimide  was  ashed under identical exper- imental
conditions using a thick (0.95 cm) and a thin  (0.16 cm)  coil.  The
plasma generated by the thick coil ashed the polyimide a...