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Devices Using Superconductor Shaped Magnetic Fields

IP.com Disclosure Number: IPCOM000120874D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 85K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+5]

Abstract

Many of the processes utilizing magnetic field enhancements, such as planar magnetron sputtering, RIE and plasma etching suffer from non-uniform field distribution. This creates selective erosion of the bombarded surface resulting in poor target utilization and uneven distribution of deposited materials in deposition, and non-uniform etching in subtractive processes.

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Devices Using Superconductor Shaped Magnetic Fields

      Many of the processes utilizing magnetic field
enhancements, such as planar magnetron sputtering, RIE and plasma
etching suffer from non-uniform field distribution.  This creates
selective erosion of the bombarded surface resulting in poor target
utilization and uneven distribution of deposited materials in
deposition, and non-uniform etching in subtractive processes.

      Magnetrons have been in use for many years as
sputter-deposition tools for thin films for electronic films,
protective layers, decorative and architectural coatings, etc.
Magnetrons suffer from an inherent problem which limits the amount of
material which can be used from the cathode/target.  This is shown in
Fig. 1.  The flaw is that the magnetic field lines 10, which are to
traverse the front of the cathode 12, originate from the magnets 14
located well behind the cathode surface.  Thus, rather than having
flat field lines, parallel to the cathode surface, the lines are
bowed above the cathode.  This leads to strong non-uniformities in
the erosion of the cathode surface, the etching rate being highest
under the area of highest field. Because the etching is greater at
these high field points, the target is more rapidly eroded.  Erosion
through the target is to be avoided, so targets are usually replaced
after only about 35% of the total material has been used. This can be
a critical, expensive problem for high purity, difficult to fabricate
materials and precious metals.

      To solve this problem an aspect of superconductivity and t...