U.S. patent application number 11/058955 was filed with the patent office on 2005-07-07 for method for making zone-bonded lubricant layer for magnetic hard discs.
Invention is credited to Gui, Jing, Ma, Xiaoding, Stirniman, Michael Joseph.
Application Number | 20050145175 11/058955 |
Document ID | / |
Family ID | 28457249 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050145175 |
Kind Code |
A1 |
Ma, Xiaoding ; et
al. |
July 7, 2005 |
Method for making zone-bonded lubricant layer for magnetic hard
discs
Abstract
A system and method for improving the durability and reliability
of recording media used in hard drives is disclosed. A protective
overcoat made by depositing a diamond like carbon (DLC) layer over
a magnetic layer and then depleting a portion of the DLC protective
layer of hydrogen before it is coated with a Perfluoropolyethers
(PFPE) using an in-situ vapor lubrication technique. The portion of
the DLC layer which is depleted can be data zone of the media so
that the lubricant-bonding ratio is higher for the landing zone
than it is for the data zone.
Inventors: |
Ma, Xiaoding; (Fremont,
CA) ; Stirniman, Michael Joseph; (Fremont, CA)
; Gui, Jing; (Fremont, CA) |
Correspondence
Address: |
Raghunath S. Minisandram
Seagate Technology LLC
920 Disc Drive, SV15B1
Scotts Valley
CA
95067
US
|
Family ID: |
28457249 |
Appl. No.: |
11/058955 |
Filed: |
February 15, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11058955 |
Feb 15, 2005 |
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10402070 |
Mar 27, 2003 |
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6878418 |
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60368681 |
Mar 29, 2002 |
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Current U.S.
Class: |
118/723R ;
G9B/5.3 |
Current CPC
Class: |
C23C 14/022 20130101;
C23C 14/12 20130101; G11B 5/8408 20130101 |
Class at
Publication: |
118/723.00R |
International
Class: |
C23C 016/00 |
Claims
We claim:
1. A system for lubricating a disk, comprising: a vacuum chamber
for reducing pressure; a surface modifier for activating a first
portion of a surface on a substrate while leaving a second portion
of said surface inactivated; and a lubrication chamber for
depositing a lubricant onto said surface of said substrate so that
a lubricant-bonding ratio between said first portion of said
surface and said lubricant is different than the lubricant-bonding
ratio between said second portion of said surface and said
lubricant.
2. A system for lubricating a disk, comprising: a thin film
deposition chamber for depositing a first layer; a surface modifier
for activating a first portion of said first layer wherein said
modifier includes a masking means for covering all areas of said
first layer except said first portion of said layer and a means of
generating and accelerating charged ions to the surface of said
first layer to activate said first portion of said first layer; and
a lubrication chamber for depositing a lubricant onto said first
layer.
3. The system of claim 2 wherein said lubrication chamber is a
vapor lubrication chamber.
4. A system for in-situ vapor lubrication, comprising: means for
exposing a first portion of a first deposited layer to positively
charged ions for surface activation of said first portion of said
first deposited layer; and means for depositing in-situ a second
layer onto said first layer, after activation of said first portion
of said first deposited layer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. provisional
application Ser. No. 60/368,681, filed on Mar. 29, 2002 and
incorporated herein by reference. This is a divisional of
co-pending application Ser. No. 10/402,070 filed on Mar. 27,
2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to magnetic discs for use in
computer disc drives, and, more particularly, to application of the
lubricant layer over the magnetic disc
[0004] 2. Description of the Related Art
[0005] Computer disc drives commonly use components made out of
thin films to store information. Both the read-write element and
the magnetic storage media of disc drives are typically made from
thin films.
[0006] FIG. 1A is an illustration showing the layers of a
conventional magnetic media structure including a substrate 105, a
seed layer 109, a magnetic layer 113, a diamond like carbon (DLC)
protective layer 117, and a lube layer 121. The initial layer of
the media structure is the substrate 105, which is typically made
of nickel-phosphorous plated aluminum or glass that has been
textured. The seed layer 109, typically made of chromium, is a thin
film that is deposited onto the substrate 105 creating an interface
of intermixed substrate 105 layer molecules and seed layer 109
molecules between the two. The magnetic layer 113, typically made
of a magnetic alloy containing cobalt (Co), platinum (Pt) and
chromium (Cr), is a thin film deposited on top of the seed layer
109 creating a second interface of intermixed seed layer 109
molecules and magnetic layer 113 molecules between the two. The DLC
protective layer 117, typically made of carbon and hydrogen, is a
thin film that is deposited on top of the magnetic layer 113
creating a third interface of intermixed magnetic layer 113
molecules and DLC protective layer 117 molecules between the two.
Finally the lube layer 121, which is a lubricant typically made of
a polymer containing carbon (C) and fluorine (F) and oxygen (O), is
deposited on top of the DLC protective layer 117 creating a fourth
interface of intermixed DLC protective layer 117 molecules and lube
layer 121 molecules.
[0007] The durability and reliability of recording media is
achieved primarily by the application of the DLC protective layer
117 and the lube layer 121. The combination of the DLC protective
layer 117 and lube layer 121 is referred to as a protective
overcoat. The DLC protective layer 117 is typically an amorphous
film called diamond like carbon (DLC), which contains carbon and
hydrogen and exhibits properties between those of graphite and
diamond. Thin layers of DLC are deposited on disks using
conventional thin film deposition techniques such as ion beam
deposition (IBD), plasma enhanced chemical vapor deposition
(PECVD), magnetron sputtering, radio frequency sputtering or
chemical vapor deposition (CVD). During the deposition process,
adjusting sputtering gas mixtures of argon and hydrogen varies the
concentrations of hydrogen found in the DLC. Since typical
thicknesses of DLC protective layer 117, are less than 100
Angstroms, lube layer 121 is deposited on top of the DLC protective
layer 117, for added protection, lubrication and enhanced disk
drive reliability. Lube layer 121 further reduces wear of the disc
due to contact with the magnetic head assembly.
[0008] A typical lubricant used in lube layer 121 is
Perfluoropolyethers (PFPEs), which are long chain polymers composed
of repeat units of small perfluorinated aliphatic oxides such as
perfluoroethylene oxide or perfluoropropylene oxide. As is well
known in the art, PFPEs are used as lubricants because they provide
excellent lubricity, wide liquid-phase temperature range, low vapor
pressure, small temperature dependency of viscosity, high thermal
stability, and low chemical reactivity. PFPEs also exhibit low
surface tension, resistance to oxidation at high temperature, low
toxicity, and moderately high solubility for oxygen. Several
different PFPE polymers are available commercially, such as Fomblin
Z (random copolymer of CF.sub.2CF.sub.2O and CF.sub.2O units) and Y
(random copolymer of CF(CF.sub.3)CF.sub.2O and CF.sub.2O) including
Z-DOL and AM 2001 from Montedison, Demnum (a homopolymer of
CF.sub.2CF.sub.2CF.sub.2O) from Daikin, and Krytox (homopolymer of
CF(CF.sub.3)CF.sub.2O).
[0009] Lube layer 121 is typically applied evenly over the disc, as
a thin film, by dipping the discs in a bath containing mixture of a
few percent of PFPE in a solvent and gradually draining the mixture
from the bath at a controlled rate. The solvent remaining on the
disc evaporates and leaves behind a layer of lubricant less than
100 Angstroms. Recent advances have enabled the application of PFPE
using an in-situ vapor deposition process that includes heating the
PFPE with a heater in a vacuum lube process chamber. In this
system, evaporation occurs in vacuum onto freshly deposited DLC
protective layer 117 that has not been exposed to atmosphere,
creating a thin uniform coating of PFPE lube layer 121.
[0010] Since it is known in the art that recording media with
higher lubricant bonded ratio has better corrosion protection and
that an in-situ vapor lubrication process enhances the bonding
between lubricants and amorphous carbon, in-situ vapor lubrication
has been used to lubricate amorphous carbon layers. In-situ vapor
lubrication of recording media is the lubrication of the recording
media immediately after the DLC protective layer 117 has been
deposited over the magnetic layer 113 without exposing it to
atmosphere.
[0011] FIG. 1B is a flow chart showing the typical steps used in an
in-situ vapor lubrication process that deposits PFPE lubricant over
a carbon layer. The process begins with step 150 by transferring a
partially complete media with substrate 105, seed layer 109, and
magnetic layer 113 into a vacuum chamber. The transferring process
typically involves moving a disk, after depositing a magnetic layer
on it, into a carbon deposition chamber without taking it out of
vacuum. In step 155 an amorphous carbon layer is deposited over the
partially complete media. Typically the amorphous carbon layer is
diamond like carbon (DLC) that has been deposited by conventional
sputter deposition techniques. Next in step 160, the amorphous
carbon is coated with a lube layer 121 of PFPE using an in-situ
vapor lubrication process. Finally, in step 165 the lubed magnetic
media is transferred to the next manufacturing operation.
[0012] The same technology, however, works less effectively with a
DLC protective layer 117. When a DLC protective layer 117 is
applied over the magnetic layer 115, unpaired carbon electrons pair
with hydrogen electrons and dangling carbon bonds are tied up, as
illustrated in FIG. 1C. FIG. 1C is an illustration showing the
carbon bonds that are not tied up by other carbon atoms being tied
up at the surface with hydrogen bonds. The termination of the
carbon bonds on the surface by hydrogen effectively reduces the
reactive sites. As a result, the bonding sites for lubricant
molecules are reduced and therefore the lubricant bonded ratio
decreases. This effect is particularly strong when lubricant is
deposited in-situ after depositing the DLC protective layer 117, as
manifested by the poor adhesion of lube layer 121 to the DLC
protective layer 117. Because of this effect, IBD or PECVD
processes, which produce DLC protective layer 117, and in-situ
vapor lubrication processes, which enhances bonding, have not been
combined to achieve the maximum performance.
[0013] The conflicting tribological requirements in the data zone
(DZ) of a magnetic disc where information is stored and the landing
zone (LZ) where a head takes-off and lands often require different
lube designs in different zones. For example, bonded lube is more
desirable in the DZ where flyability corrosion protection are the
primary concerns, whereas sufficient mobile lube is essential in
the LZ where wear durability is of greater importance. While the
benefit of zone lubrication to satisfy both requirements has been
recognized in the art, the known methods generally focus on
post-lubrication treatments by either partial removal or by zone
radiation. These additional steps could add considerable complexity
to the disc manufacturing process. Particularly, in the case of
in-situ vapor lubrication process, these post-lubrication
treatments defeat the main benefit of the in-situ vapor lube
process, i.e., simplicity and low cost.
[0014] Therefore what is needed is a system and method which
overcomes these problems and makes it possible to apply a lubricant
to a carbon overcoat using an in-situ vapor lubrication process
that results in a reliable final overcoat with desirable
properties. Desirable properties include a resulting lubricant that
is bonded to the carbon overcoat more strongly at the data zone
than at the landing zone.
SUMMARY OF THE INVENTION
[0015] This limitation is overcome by depleting hydrogen from the
diamond like carbon layer at the data zone while leaving the
landing zone alone. Depleting hydrogen from the diamond like carbon
layer prior to the application of the lube layer enhances the bond
between the diamond like carbon protective layer and the lube
layer. Therefore depleting hydrogen from the diamond like carbon
layer at the data zone while leaving the landing zone alone
enhances the bond between the diamond like carbon layer and the
lube at the data zone without effecting the existing bond between
the diamond like carbon layer and lubricant at the landing
zone.
[0016] Depletion of hydrogen in the data zone activates the surface
of the DLC protective layer 117, in the data zone, by creating
unpaired electrons in the DLC that are ready to react. The unpaired
electrons create a strong bond between the DLC protective layer 117
and the lube layer 121.
[0017] The data zone of the DLC protective layer 117 is depleted of
hydrogen by bombarding the data zone with argon ions. The hydrogen
atoms are ejected from the surface of the data zone DLC protective
layer 117 when the accelerated argon ions collide with them.
[0018] These and various other features as well as advantages which
characterize the present invention will be apparent upon reading of
the following detailed description and review of the associated
drawings.
BRIEF DESCRIPTION OF THE INVENTION
[0019] FIG. 1A is a block diagram showing a prior art conventional
magnetic media structure;
[0020] FIG. 1B is a flowchart illustrating the prior art method of
using in-situ vapor lubrication on a carbon layer;
[0021] FIG. 1C is an illustration of a prior art DLC protective
layer ready to be lubed;
[0022] FIG. 2 is an illustration of a DLC protective layer, with
the landing zone being Hydrogen Depleted DLC (HDDLC), ready for
in-situ vapor lubrication, in accordance with an embodiment of the
invention;
[0023] FIG. 3 is a block diagram showing the HDDLC layer 200 in a
magnetic media environment;
[0024] FIG. 4 is a flowchart showing the preferred method of
depositing the protective overcoat including the HDDLC layer 200
and the lube layer 121;
[0025] FIG. 5 is a block diagram showing a thin film deposition
system used to deposit the magnetic media structure 300; and
[0026] FIG. 6 is an illustration showing details of surface
modifier 520 of system 500 of FIG. 5.
[0027] FIG. 7 is a bar graph comparing the percentage of bonded
lubricant, which is deposited using vapor deposition and dipping,
on hydrogenated carbon that has been activated with argon ions.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] The invention provides a system and method for protecting
magnetic media.
[0029] FIG. 2 is an illustration of a partially hydrogen depleted
DLC (HDDLC) layer 200, with the data zone, landing zone and
transition zone clearly demarcated, ready for in-situ vapor
lubrication, in accordance with one embodiment of the invention.
The data zone, which is shown to be hydrogen depleted, is the
portion of the magnetic media from where data is recorded and
retrieved. The landing zone, which is shown not to be hydrogen
depleted, is the portion of the magnetic media where the head comes
to rest when the magnetic media stops spinning. The transition
zone, which is shown to be partially hydrogen depleted, is the
region of the magnetic media separating the landing zone from the
data zone where the data zone transitions into the landing zone.
The HDDLC layer 200 includes a plurality of carbon atoms 210, a
plurality of hydrogen atoms 220, a plurality of carbon-hydrogen
bonds 230, a plurality of carbon-carbon bonds 240 and a plurality
of free dangling carbon bonds 250.
[0030] The free dangling carbon bonds 250 are created by bombarding
a portion, corresponding to the data zone, of the DLC protective
layer 117 with charged ions as is furthered described with
reference to FIG. 4 below. This bombardment process converts the
DLC protective layer 117 into a more reactive HDDLC layer 200 by
creating free dangling bonds 250 in the data zone. This increases
the bonding between the hydrogen depleted portion of the HDDLC 200
layer and the lubricant that is deposited over the entire HDDLC
layer 200 with an in-situ vapor lube process as is described with
reference to FIG. 4 below.
[0031] FIG. 3 is a block diagram showing the HDDLC layer 200 in a
magnetic media environment 300 including a substrate 105, a seed
layer 109, a magnetic layer 113, a lube layer 121, and a hydrogen
depleted region 310. The hydrogen-depleted region 310 is the same
region as the data zone region discussed with reference to FIG. 2,
above. HDDLC layer 200 protects magnetic media from wear and tear
as does DLC protective layer 117 except that it has been modified
so that the lube layer 121 adheres to the data zone, which
corresponds to the hydrogen depleted region 310, much better than
it otherwise would, providing improved protection.
[0032] FIG. 4 is a flow chart showing the preferred steps used to
make a protective overcoat including an HDDLC layer 200 and in-situ
lubed layer 121. Protective overcoats typically include a hard
layer such as DLC and a lubrication layer. The process begins with
step 405 by transferring a partially complete media having
substrate 105, seed layer 109, and magnetic layer 113 into a vacuum
chamber. The transferring process typically involves moving a disk,
after depositing a magnetic layer on it, into a carbon deposition
chamber without taking it out of vacuum.
[0033] Next in step 410, a DLC protective layer 117 containing
carbon and hydrogen is deposited onto the substrate. The deposition
process can be done by various thin film deposition techniques
including ion beam deposition (IBD), plasma enhanced chemical vapor
deposition (PECVD), magnetron sputtering, radio frequency
sputtering, or chemical vapor deposition (CVD). In one embodiment,
the DLC protective layer 117 is prepared by ion beam deposition
using a work gas is C.sub.2H.sub.2. The energy per C atom is 90
eV.
[0034] Next in step 415, the DLC protective layer 117 is masked so
that only a portion of it will be hydrogen depleted. The masking
can be done by placing a shield in front of the portions of the DLC
protective layer that will not be hydrogen depleted, as is further
discussed with reference to FIG. 6 below. The masking is typically
done by covering the entire media except in places that are to be
hydrogen deleted. For example, placing a shield in front of the
magnetic media in all places except the data zone will mask the
media so that only the data zone is hydrogen depleted in the
subsequent step 420.
[0035] In step 420, the masked DLC protective layer 117 is exposed
to argon ions (Ar.sup.+), from an argon ion plasma, which depletes
the unmasked areas of the DLC protective layer 117 of hydrogen
atoms. Exposing includes bombarding the DLC protective layer 117
with ions that are accelerated by an electric field as well as
allowing atoms, molecules or ions to randomly strike the DLC
protective layer 117 in the absence of an electric field. As
Ar.sup.+ ions bombard the DLC protective layer 117, hydrogen atoms
are ejected, reducing the number of hydrogen atoms left on the DLC
protective layer 117, creating an HDDLC layer 200. The depletion of
hydrogen activates the DLC by making it a reactive carbon. The
HDDLC is reactive because carbon atoms that were once bonded to
hydrogen atoms now have unpaired electrons available for bonding.
Although, the preferred process of removing hydrogen atoms from the
DLC layer 117 is the mechanical process of Ar.sup.+ ion
bombardment, other processes including chemical processes can be
used.
[0036] Step 420 can be done in the same chamber as that in which
the DLC protective layer 117 is deposited or it can be done in a
different chamber. If step 420 is performed in a second vacuum
chamber then the partially complete media is transferred to a
second chamber after the DLC protective layer 117 is deposited. The
transferring process is done under vacuum or in an inert
environment such as argon. The application of the mask in step 415
can be done in the DLC deposition chamber, the transfer process or
the argon bombardment chamber.
[0037] In the preferred embodiment, the rate at which hydrogen
atoms are removed from the DLC protective layer 117 can be adjusted
by changing parameters such as voltages, pressures, flow rates, and
temperatures. Voltage controls the electric field acting on the
Ar.sup.+ ions and consequently the force with which Ar.sup.+ ions
bombard the DLC protective layer 117. Bombarding occurs when the
ions are accelerated towards the DLC protective layer 117, because
of the electric field acting on the Ar.sup.+ ions, and collide with
the DLC protective layer 117. Pressure and flow rates control
physical properties of the plasma such as the number of Ar.sup.+
ions available to bombard the DLC protective layer 117. Temperature
controls the kinetic energy at the surface of the DLC protective
layer 117 and consequently the amount of energy that must be
imparted to the surface to remove hydrogen atoms.
[0038] In the preferred embodiment the plasma is made out of
ionized argon. Argon is used in the preferred embodiment because it
is inert and readily available. However, other inert gases such as
helium (He), neon (Ne), krypton (Kr) or xenon (Xe) can also be used
to make up the plasma of charged ions, which bombard the DLC
protective layer 117 and remove hydrogen atoms from it. In one
embodiment, step 415 is done immediately after deposition where Ar
gas is introduced into the process chamber at a flow rate of 10
sccm. The argon is ionized, in the plasma, and accelerated causing
the argon ions to bombard the unmasked portions of the DLC films.
The duration for this process is 0.5 seconds.
[0039] Noble gases are preferred because they are inert and do not
chemically react with the DLC protective layer 117. This enables
the removal hydrogen atoms from the DLC protective layer 117 by the
mechanical process of bombardment. The invention, however, is not
limited to only using noble gases because this process can be
carried out using non-noble gases which do not chemically react
with the DLC protective layer 117. Additionally, this invention is
not limited to the removal of hydrogen atoms from the DLC
protective layer 117 by mechanical means only. Other methods such
as heating the DLC protective layer 117 or chemically reacting
another substance with the DLC protective layer 117 can be used to
remove hydrogen atoms from the DLC protective layer 117.
[0040] Next in step 425, an in-situ vapor deposition technique is
used to apply a lubricant onto a partially completed media
completing the protective overcoat. In the preferred embodiment
PFPE is applied to the partially completed media using an in-situ
vapor deposition process that includes heating the lubricant with a
heater in a vacuum lube process chamber. In this embodiment,
evaporation of PFPE occurs in a vacuum onto HDDLC 200 after the DLC
protective layer 117 has been deposited and a portion of its
surface depleted of hydrogen 310 by exposing it to ionized argon
without exposing the HDDLC 200 to atmosphere. The portion of the
DLC surface depleted of hydrogen 310, which corresponds to the data
zone in this application, bonds stronger to the lubricant than the
portion of the DLC surface that has not been depleted of hydrogen,
which in this application corresponds to the landing zone.
[0041] Finally in step 430 the lubed magnetic media is transferred
to the next manufacturing operation.
[0042] Although the preferred steps used to make a protective
overcoat are described in reference to a DLC protective layer 117
and lube layer 121, those skilled in the art will recognize that
the same steps can be used to deposit any two layers, wherein the
bonding between the two layers is improved or where it is desirable
to provide areas of differential bond strength. For example, a
first layer, which can be metallic, insulating, semi-conducting or
semi-metallic, can be deposited as described with reference to step
410. The first layer can then be masked in step 415 so that only
the portions of the first layer that are to be activated are
uncovered and the remaining portions of the first layer are
covered. The first layer is then activated as described with
reference to step 420. After the first layer is activated, a second
layer, which can also be metallic, insulating, semi-conducting or
semi-metallic, can be deposited as described with reference to step
425. The combination of the first layer and second layer can then
be transferred to the next manufacturing operation as described in
step 425.
[0043] FIG. 5 represents a multilayer thin film deposition system
500 equipped with an in-situ DLC deposition system, a carbon
surface modifying system and a vapor lube system. System 500
preferably includes a loader 510, a DLC depositor 515, a surface
modifier 520, a vapor luber 525, an unloader 530, a controller 535,
a power system 540, a pumping system 545 and a gas flow system
550.
[0044] Loader 510 and unloader 530 represent conventional load
locks that allow substrates to be transferred into and out of a
vacuum chamber without venting the entire vacuum system. DLC
depositor 515 represents a conventional thin film deposition
chamber used to deposit the DLC protective layer 117. DLC depositor
515 can use ion beam deposition (IBD), plasma enhanced chemical
vapor deposition (PECVD), magnetron sputtering, radio frequency
sputtering or chemical vapor deposition (CVD) techniques to deposit
the DLC protective layer 117. Surface modifier 520 is used to
deplete a portion of the top surface of the DLC protective layer
117 of hydrogen, creating HDDLC layer 200 as is further discussed
with reference to FIG. 4 above. Although surface modifier 520 is
shown separate from DLC depositor 515 and vapor luber 525, surface
modifier 520 can be incorporated into DLC depositor 515 or vapor
luber 525.
[0045] Vapor luber 525 represents a conventional vapor lubing
system used to deposit the lube layer 121 onto the HDDLC layer 200.
Controller 535 is the software and hardware that controls the
operation of system 500. Power system 540 represents power supplies
used to power the system 500 and include power supplies for
heaters, conveyers, DC magnetrons, rf sources. Pumping system 545
represents all pumps and valves used to evacuate the vacuum
chambers including mechanical pumps, turbo pumps, cryogenic pumps
and gate valves. Gas flow system 550 represents the gas delivery
equipment such as mass flow controllers, valves, piping and
pressure gauges.
[0046] FIG. 6 is an illustration showing surface modifier 520
depleting hydrogen atoms from a portion of the top surface of the
DLC protective layer 117. In one embodiment, surface modifier 520
includes a vacuum chamber 605, an argon ion plasma 610, argon ions
(Ar.sup.+) 615, a first voltage V.sub.1 620, a second voltage
V.sub.2 625, a stage 630, and a mask 635 depleting hydrogen atoms
from a portion of the top surface of the DLC protective layer 117
of a partially completed media.
[0047] After depositing the DLC protective layer 117, as discussed
with reference to FIG. 1B, a portion of the top surface of the DLC
protective layer 117 is exposed to an argon ion plasma 610
consisting of (Ar.sup.+) ions 615. In step 415, the partially
complete media is moved to a grounded vacuum chamber 605 that is
maintained at process pressures ranging from 10.sup.-3 torr to
10.sup.-2 torr. Power supplies such as the Advanced Energy MDX
series manufactured by Advanced Energy of Fort Collins, Colo., USA
are used to maintain the DLC protective layer 117 and the mask 635
at a first voltage V.sub.1 615 and the argon ion plasma at a second
voltage V.sub.2 625. The voltage difference between the plasma and
the DLC protective layer 117 and the mask 635 creates an electric
field 630 that accelerates the Ar.sup.+ ions towards the DLC
protective layer 117 and mask 635. The actual trajectory 635 of the
argon ions depends on many factors including the initial velocity
of the ions and the configuration of the electric field, which is
determined by the first voltage 620 and the second voltage 625.
[0048] In this embodiment, the purpose of the mask 635 is to block
the ions 615 from bombarding the DLC layer 117 at the areas where
the mask 635 is located. In other embodiments where the activation
of the DLC surface is done by chemical means purpose of the mask
635 is to prevent the activating chemicals from reacting with the
surface at positions where the mask is located.
[0049] FIG. 7 is a graph showing the lubricant-bonding ratio with
and without Argon sputtering for both lubricants applied using a
vapor lube techniques and a dipping techniques. For lubricant
applied using vapor lubrication techniques the bonding ratio
increases from about 72% to about 90% by activating the surface
with positive argon ions. Similarly, for lubricant applied using
dipping techniques the bonding ratio increases from about 49% to
about 54% by activating the surface with positive argon ions. In
both cases the data suggests that bombarding the surface of the DLC
with positive argon ions makes the surface more reactive and
increases the lubricant-bonding ratio between the DLC surface and
the lubricant.
[0050] It will also be recognized by those skilled in the art that,
while the invention has been described above in terms of preferred
embodiments, it is not limited thereto. Various features and
aspects of the above-described invention may be used individually
or jointly. Further, although the invention has been described in
the context of its implementation in a particular environment and
for particular applications, those skilled in the art will
recognize that its usefulness is not limited thereto and that the
present invention can be utilized in any number of environments and
implementations.
* * * * *