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Magnetron Shunt for Enhanced Performance of Sputter Targets

IP.com Disclosure Number: IPCOM000106424D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

German, JR: AUTHOR

Abstract

Magnetron sputtering targets are most efficient when the trapping field is parallel to the target surface. A shunt is disclosed which improves this feature for many common electrode designs.

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Magnetron Shunt for Enhanced Performance of Sputter Targets

      Magnetron sputtering targets are most efficient when the
trapping field is parallel to the target surface.  A shunt is
disclosed which improves this feature for many common electrode
designs.

      Most magnetron sputtering electrodes require a water cooling
jacket behind the target.  This usually increases the separation
between the target surface and the magnetron field generating
magnets.  The greater this separation the more curvature there is in
the equipotential field lines just above the target surface.  The end
result of this situation is an uneven erosion of the target into
deep, narrow racetrack regions.  This region can be made broader and
can be eroded more evenly by placing a simple shim of permeable
material behind the target.

      Fig. 1 is a cross section of a typical magnetron that shows the
equipotential magnetic field lines.  The magnetron effect is
strongest at the top of the arcs where the field is parallel to the
target.  Fig. 2 shows the configuration modified by a shim made of
cold rolled steel.  Modelling shows that the shim shunts the path of
the magnetic field and flattens the equipotential lines near the
target surface.  This simple modification can as much as double
target material utilization.  Also, differential sputter rates are
lowered as more area contributes to the integrated deposition flux.
This can be useful in limiting power dependent defects suc...