Cathodes for sputtering magnetic materials

Magnetic targets represent the most difficult challenge for utilization in the sputtering industry. High permeability materials create an inconsistent, non-linear environment for magnetic fields, severely decreasing utilization. For example, permalloy targets produce typically pinched grooves, causing a premature burn-through on the target. Under these conditions, sputtering characteristics change dramatically over the life of the target. Our patented designs (U.S. Patent #5,415,754) for magnetic targets avoid this pinching problem and provide uniform sputtering conditions throughout the target life. Sierra typically achieves between 15-20% for the same permalloy targets while our competitors typically achieve 4%-5% usage for the same materials.
Shown are two eroded permalloy targets and one nickel target.
Target
Material
Target
Thickness (in)
%Utilization
Sierra
Design
  Other
Design
CoCr Alloys
Nickel
Permalloy
Iron
CoFe Alloys
0.375
0.250
0.200
0.200
0.200
30
17
15
15
16
15
 6
 5
 4
 4
Typical results using Sierra's design for magnetic materials (U.S. Patent #5,415,754)
show a two- to four-fold increase in target utilization.