US5512150A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Target assembly having inner and outer targets
Assignee: WD Media LLC
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Filing: 1995-03-09
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Granted: 1996-04-30
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Expires: 2015-03-09
Abstract
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.
Inventors
- 👤 Allen J. Bourez
- 👤 Brij B. Lal
- 👤 Michael A. Russak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:59
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/34; H01J37/3411; H01J37/3414; H01J37/3426; H01J37/3429; C; C23; C23C; C23C14/00; C23C14/22; C23C14/34; C23C14/3407; C23C14/35; G; G11; G11B; G11B5/00; G11B5/84; G11B5/851; H01J37/3402; H01J37/3405; H01J37/3408; H01J37/345; H01J37/3458
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
153 words
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.
Claim 2
Dependent Claim
153 words
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.
Claim 3
Dependent Claim
22 words
The assembly of claim 1, wherein said inner magnetic means is a permanent magnet and said outer magnetic means is an electromagnet.
Claim 4
Dependent Claim
35 words
The assembly of claim 2, wherein said electromagnet in said one polarity has a current of between 0.1 and 1.0 amp, and in said opposite polarity has a current of between 1.0 and 5.0 amps.
Claim 5
Dependent Claim
23 words
The assembly of claim 1, wherein said inner target is composed of chromium and said outer target is composed of a cobalt-based alloy.
Claim 6
Dependent Claim
58 words
The assembly of claim 1, wherein said outer target further includes an inner ring and an outer ring, both formed of substantially the same material as said outer target, the inner ring being positioned adjacent an inner annular region of said outer target, and said outer ring being positioned adjacent an outer annular region of said outer target.
Claim 7
Dependent Claim
25 words
The assembly of claim 5, wherein an outer annular portion of said inner target is disposed adjacent an upper annular portion of said inner ring.
Claim 8
Dependent Claim
29 words
The assembly of claim 1, further comprising a means for placing a negative bias of between -50 to -500 volts on said substrate during sputter deposition of said layers.
Claim 9
Independent Claim
191 words
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.
Claim 10
Independent Claim
191 words
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.
Claim 11
Dependent Claim
23 words
The method of claim 8, wherein said orienting is accomplished by controlling a coil current amperage and direction in said outer magnetic means.
Claim 12
Dependent Claim
22 words
The method of claim 9, wherein said controlling includes adjusting in an electromagnet said coil current amperage to between about 0.1-1.0 amp.
Claim 13
Dependent Claim
43 words
The method of claim 8, wherein said reversing is accomplished by controlling a coil current amperage and direction in said outer magnetic means, which is in the form of an electromagnet, and said coil current amperage is adjusted to between about 1.0-5.0 amps.
Claim 14
Dependent Claim
32 words
The method of claim 8, wherein said sputtering from said inner target is from a chromium inner target, and said sputtering from said outer target is from a cobalt-based alloy outer target.
Claim 15
Dependent Claim
37 words
The method of claim 12, wherein said sputtering steps are effective to form a magnetic recording medium having at least two magnetic thin-film layers separated by a chromium interlayer layer having a thickness of between 5-50 Å.
Claim 16
Dependent Claim
32 words
The method of claim 12, wherein said sputtering from said inner target is effective for deposition of a chromium underlayer and for deposition of a chromium interlayer in a magnetic recording medium.
Claim 17
Dependent Claim
23 words
The method of claim 8, wherein said orienting includes supplying power to the inner target at the preselected level of between 0.3-1.0 KW.
Claim 18
Dependent Claim
23 words
The method of claim 8, wherein said reversing includes supplying power to the outer target at the preselected level of between 1.0-2.5 KW.
Claim 19
Independent Claim
129 words
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.
Claim 20
Independent Claim
129 words
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.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-04-30 | 1999-10-30 | 2000-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-30 | 2003-10-30 | 2004-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-30 | 2007-10-30 | 2008-04-30 | $7700.00 | Window Closed / Lapsed |