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ECR-Sputter Source for Deposition of Metals at Very Low Pressures

IP.com Disclosure Number: IPCOM000102607D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Grabarz, H: AUTHOR [+5]

Abstract

A number of applications in semiconductor processing exist for a metal deposition source which has a high ion to neutral impingement ratio. With a high ion content, better control can be exercised over the characteristics of the deposited metal films. One method of achieving this goal is by combining a negatively biased metal sputter target with an ECR plasma source. Supplying microwave radiation at a frequency of 2.45 MHz in a magnetic field of 875 Gauss, it is impossible to obtain high density plasma (>3 x 1011cm-3), uniform over a large area, at very low pressures (10-3 Torr, or less) (1). The plasma is sustained near the target and the high current density of ions is extracted towards the target, along the magnetic field lines.

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ECR-Sputter Source for Deposition of Metals at Very Low Pressures

       A number of applications in semiconductor processing
exist for a metal deposition source which has a high ion to neutral
impingement ratio.  With a high ion content, better control can be
exercised over the characteristics of the deposited metal films.  One
method of achieving this goal is by combining a negatively biased
metal sputter target with an ECR plasma source.  Supplying microwave
radiation at a frequency of 2.45 MHz in a magnetic field of 875
Gauss, it is impossible to obtain high density plasma (>3 x
1011cm-3), uniform over a large area, at very low pressures (10-3
Torr, or less) (1).  The plasma is sustained near the target and the
high current density of ions is extracted towards the target, along
the magnetic field lines.  Having the magnetic field lines normal to
the surface of the target allows an efficient extraction of the ions
from the plasma.

      The sputtered metal particles enter the ECR zone where they are
ionized.  A fraction of the ions will be extracted along the
diverging magnetic field lines, towards the wafer to be coated, while
the rest of the ions are accelerated back toward the target,
resulting in self-sputtering of the metal.  The occurrence of the
self-sputtering should allow further reduction of the pressure of the
sputtering gas, after the initiation of the discharge.

      A combination of an ECR source with a sputtering source has
been reported (2).  Here, 10.56 GHz microwave power is fed in front
of the target by means of a waveguide inserted inside the reactor.
Such an...