Target assembly having inner and outer targets
AssigneeHMT Technology Corporation
InventorsAllen J. Bourez, Brij B. Lal, Michael A. Russak
Life of this patent
Estimating the term…
Abstract
A target assembly for use in fabricating magnetic recording media is described. The target assembly has inner and outer concentric targets for sputter depositing on a substrate first and second layers having different compositions. Disposed adjacent each target is a magnetic means, and at least one which is reversible in magnetic-pole polarity. One polarity produces a magnetic flux sufficient to ignite a sputtering plasma in the inner target only, when power is supplied to the inner target at a preselected level. The opposite polarity produces a magnetic flux sufficient to ignite a sputtering plasma in the outer target only, when power is supplied to the outer target at a preselected level.
Claims17
A target assembly for use in forming on a substrate, first and second sputter-deposited layers having different compositions, said assembly comprising:
- inner and outer concentric targets for sputter depositing said layers on the substrate,
- inner magnetic means disposed adjacent an inner annular portion of said inner target, and having a substantially axial magnetic pole orientation,
- outer magnetic means disposed adjacent the outer target and an outer annular region of the inner target, and having a substantially radial magnetic pole orientation,
- at least one of said magnetic means being reversible in magnetic-pole polarity, wherein one polarity produces a magnetic flux sufficient to ignite a sputtering plasma in the inner target only, when power is supplied to the inner target at a preselected level, and the opposite polarity produces a magnetic flux sufficient to ignite a sputtering plasma in the outer target only, when power is supplied to the outer target at a preselected level.
A method of forming on a substrate by sputter deposition, alternating layers of two different compositions, said method comprising:
- placing said substrate in a sputtering chamber having a target assembly with inner and outer concentric targets, and having inner and outer magnetic means disposed adjacent said inner and outer targets, respectively, where at least one of said magnetic means is reversible in magnetic-pole polarity, and one polarity produces a magnetic flux sufficient to ignite a sputtering plasma in the inner target only, and the opposite polarity produces a magnetic flux sufficient to ignite a sputtering plasma in the outer target only,
- orienting the polarity of one of said magnetic means to achieve ignition of a sputtering plasma in the inner target, when power is supplied to the inner target at a preselected level;
- sputtering from said inner target, a layer onto said substrate;
- reversing the polarity of said one magnetic means to achieve ignition of a sputtering plasma in the outer target, when power is supplied to the outer target at a preselected level;
- and
- sputtering from said outer target, a layer directly on the layer sputtered from said inner target.
A method for forming on a substrate a magnetic recording medium having at least two sputtered layers of different compositions, an improvement for enhancing the coercivity of the medium, comprising,
- sputtering said layers from a target assembly having inner and outer concentric targets, and having inner and outer magnetic means disposed adjacent said inner and outer targets;
- orienting the polarity of at least one of said magnetic means to achieve ignition of a sputtering plasma in the inner target only, when power is supplied to the inner target at a preselected level;
- and
- reversing the polarity of said one magnetic means to produce a magnetic flux sufficient to ignite a sputtering plasma in the outer target only, when power is supplied to the outer target at a preselected level.
Dependencies are inferred from the claim text.