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Optimized Target and Magnetron Design for Magnetic Material Sputtering

IP.com Disclosure Number: IPCOM000106398D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 182K

Publishing Venue

IBM

Related People

German, JR: AUTHOR

Abstract

Magnetron sputtering of magnetic materials presents special problems to the electrode designer. Conventional designs may require that the target be made thin so that it can be saturated by the imposed field thus still allowing a trapping field to be established over the surface. However, these are often undesirable because the erosion profiles are narrow and the resultingly low material utilization necessitates frequent target changes which limit productivity. A common approach to circumventing these problems is to employ a recessed racetrack structure. In this design iron cores, embedded in the copper electrodes, convey the magnetic field up along either side of the racetrack and over the erosion zones through caps made of the same target material.

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Optimized Target and Magnetron Design for Magnetic Material Sputtering

      Magnetron sputtering of magnetic materials presents special
problems to the electrode designer.  Conventional designs may require
that the target be made thin so that it can be saturated by the
imposed field thus still allowing a trapping field to be established
over the surface.  However, these are often undesirable because the
erosion profiles are narrow and the resultingly low material
utilization necessitates frequent target changes which limit
productivity.  A common approach to circumventing these problems is
to employ a recessed racetrack structure.  In this design iron cores,
embedded in the copper electrodes, convey the magnetic field up along
either side of the racetrack and over the erosion zones through caps
made of the same target material.  In this manner the magnetic flux
is decoupled from the material being sputtered.  Thick racetrack
sections can be eroded with good utilization, in this design,
resulting in long target life.  Disclosed here is a modification to
this design style which improves upon the original concept by
eliminating some of the common problems of undercutting, flaking,
spitting, and shorting.  This improvement is made by integrating the
cap pieces and racetrack piece into one sculpted piece and by
alteration of the magnetron magnet to apply the appropriately modeled
field.  The electrode itself remains unchanged.

      This magnetron/target configuration is designed to address
several of the problems experienced in the sputtering of magnetic
materials; short circuiting caused by flakes developing in and
falling from gaps between target pieces, target burn-through on the
sides of the target, target spitting, and errors in target assembly.
Fig. 1A shows a cross section of a recessed racetrack electrode used
to sputter magnetic materials.  The pieces labeled "Mag" are the
magnetic alloy materials being sputtered.  The upper pieces (caps)
and the lower pieces (racetrack) are separated by a 1mm diameter
copper wire placed at the edges of the racetrack.  Fig. 1B maps the
flux of the left erosion zone (from Fig. 1A) and includes an outline
of a typical erosion profile for a well worn target.  Note that on
th...