U.S. patent application number 12/472288 was filed with the patent office on 2010-12-02 for electro-deposited passivation coatings for patterned media.
This patent application is currently assigned to WD MEDIA, INC.. Invention is credited to PAUL C. DORSEY, ANDREW HOMOLA, DAVID TREVES, CHUNBIN ZHANG.
Application Number | 20100300884 12/472288 |
Document ID | / |
Family ID | 43219008 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100300884 |
Kind Code |
A1 |
HOMOLA; ANDREW ; et
al. |
December 2, 2010 |
ELECTRO-DEPOSITED PASSIVATION COATINGS FOR PATTERNED MEDIA
Abstract
A method of fabricating a patterned magnetic recording disk is
described. The method may include electrodepositing a protection
layer on the magnetic recording layer of the disk.
Inventors: |
HOMOLA; ANDREW; (NAPLES,
FL) ; ZHANG; CHUNBIN; (FREMONT, CA) ; DORSEY;
PAUL C.; (SUNNYVALE, CA) ; TREVES; DAVID;
(PALO ALTO, CA) |
Correspondence
Address: |
WESTERN DIGITAL TECHNOLOGIES, INC.;ATTN: LESLEY NING
20511 LAKE FOREST DR., E-118G
LAKE FOREST
CA
92630
US
|
Assignee: |
WD MEDIA, INC.
San Jose
CA
|
Family ID: |
43219008 |
Appl. No.: |
12/472288 |
Filed: |
May 26, 2009 |
Current U.S.
Class: |
205/50 ;
205/119 |
Current CPC
Class: |
G11B 5/8408 20130101;
G11B 5/855 20130101; G11B 5/858 20130101; G11B 5/31 20130101; G11B
5/72 20130101 |
Class at
Publication: |
205/50 ;
205/119 |
International
Class: |
G11B 5/85 20060101
G11B005/85; C25D 7/00 20060101 C25D007/00; C25D 5/02 20060101
C25D005/02; G11B 5/70 20060101 G11B005/70; G11B 5/82 20060101
G11B005/82; G11B 5/858 20060101 G11B005/858 |
Claims
1. A method of fabricating a magnetic recording disk, comprising:
providing a magnetic recording layer having a pattern of raised
areas and recessed areas formed thereon; providing a mask layer on
the raised areas of the magnetic recording layer; electrodepositing
a first protection layer on the magnetic recording layer; removing
the mask layer; and depositing a second protection layer above the
first protection layer.
2. The method of claim 1, wherein eletrodepositing comprises
electroplating.
3. The method of claim 2, wherein electroplating comprises
depositing material of the first protection layer only in the
recessed areas of the magnetic recording layer.
4. The method of claim 3, the first protection layer comprises a
metal.
5. The method of claim 3, wherein the first protection layer
comprises aluminum.
6. The method of claim 3, wherein the first protection layer
comprises a silicate.
7. The method of claim 3, wherein the first protection layer
comprises an insulator.
8. The method of claim 7, further comprising baking the first
protection layer after electrodepositing and before depositing the
second protection layer.
9. The method of claim 3, where the first protection layer
comprises an aluminate.
10. The method of claim 3, wherein the first protection layer
comprises a material selected from a group consisting of aluminum,
gold, copper, chromium, ruthenium, platinum and rhodium.
11. The method of claim 3, wherein after electroplating the method
further comprises: rinsing the first protection layer; and
annealing the first protection layer before removing the masking
layer.
12. The method of claim 11, wherein the masking layer comprises a
non-conductive material.
13. The method of claim 3, wherein the first protection layer has a
thickness less than 1 micron.
14. The method of claim 3, further comprising electrodepositing one
or more additional films on the first protection layer before
depositing the second protection layer.
15. The method of claim 1, wherein eletrodepositing comprises
electroless plating the first protection layer on the mask layer
and the recessed areas of the magnetic recording layer; and wherein
removing the mask layer comprises, removing the mask layer to lift
off overlaying first protection layer.
16. A magnetic recording disk, comprising: a magnetic recording
layer having a pattern of raised areas and recessed areas; an
electrodeposited first protection layer disposed only on the
recessed areas; and a second protection layer disposed on the
electrodeposited first protection layer and the raised areas of the
magnetic recording layer.
17. The magnetic recording disk of claim 16, wherein the
electrodeposited layer comprises a metal.
18. The magnetic recording disk of claim 16, wherein the
electrodeposited layer comprises a silicate.
19. The magnetic recording disk of claim 16, wherein the
electrodeposited layer comprises an aluminate.
20. The magnetic recording disk of claim 16, wherein the
electrodeposited layer comprises a material selected from a group
consisting of aluminum, gold, copper, chromium, ruthenium, platinum
and rhodium.
21. The magnetic recording disk of claim 16, wherein the
electrodeposited layer comprises a material having a crystalline
structure.
22. The magnetic recording disk of claim 16, wherein the
electrodeposited layer comprises a material having an amorphous
structure.
Description
TECHNICAL FIELD
[0001] Embodiments described herein relate to the field of
patterned media, and, in particularly, to electro-deposited
passivation of pattern media.
BACKGROUND
[0002] Patterned media poses unique challenges to the tribological
properties of hard disks because typical fabrication processes can
involve producing topography (e.g., grooves) in the magnetic media
layers. The non-planar media surface can adversely affect a disk
drive's performance in terms of both head flyability and corrosion.
In conventional hard disk media, the head flies over a very smooth
surface and the magnetic layers, which are composite metal films,
are capped with a thin diamond-like carbon (DLC) film to protect
against corrosion. In patterned media, a DLC film is also typically
required to cap the magnetic layers, but the presence of topography
in the magnetic layers can result in poor conformal coverage (e.g.,
groove sidewalls and corners) resulting in inadequate corrosion
performance.
[0003] In conventional fabrication process for patterned media, the
DLC film is applied to the pattern features of the discrete track
recording (DTR) disk, also referred to as discrete track media
(DTM). One type of DTM structure utilizes a pattern of concentric
discrete zones for the recording medium. When data are written to
the recoding medium, the discrete magnetic areas correspond to the
data tracks. The substrate surface areas not containing the
magnetic material isolate the data tracks from one another. The
discrete magnetic zones (also known as hills, lands, elevations,
etc.) are used for storing data and the non-magnetic zones (also
known as troughs, valleys, grooves, etc.) provide inter-track
isolation to reduce noise. The lands have a width less than the
width of the recording head such that portions of the head extend
over the troughs during operation. The lands are sufficiently close
to the head to enable the writing of data in the magnetic layer.
Therefore, with DTM, data tracks are defined both physically and
magnetically
[0004] In conventional fabrication of DTM, the recessed (e.g.,
grooves) and non-recessed regions (e.g., lands) of the patterned
area are coated at the same time using the same diamond-like carbon
(DLC) deposition process. As a result, the coating of the recessed
regions will be thinner and less uniform than the non-recessed
regions because of shadowing effects and a larger surface area in
the recessed regions. Consequently, the potential for corrosion in
the recessed regions of the patterned media is greater than the
non-recessed regions and likewise greater than standard
non-patterned media.
[0005] One conventional DTM fabrication approach uses a physical
vapor deposition (PVD) technique to coat the entire surface of
patterned magnetic layer. Such an approach may involve multi-steps
of depositing and etching back films to completely fill recessed
regions of the patterned media and achieve a flyable surface.
[0006] Another conventional DTM fabrication method described in US
2008/0187779 utilizes atomic layer deposition (ALD) to deposit a
DLC film over the entire surface of the patterned magnetic
recording layer, after installing a resin mold mask on the surface
of magnetic recording layer. The ALD fills not only the grooves but
also covers the resin mold mask on the lands of the magnetic
recording layer. Then, the resin mold mask is removed together with
the ALD protective layer above the lands of the magnetic recording
layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments are illustrated by way of example, and not
limitation, in the figures of the accompanying drawings in
which:
[0008] FIG. 1 is a conceptual illustration of the manufacturing
method and resulting disk structure of a patterned magnetic
recording disk having an electrodeposited protection layer,
according to embodiments of the present invention.
[0009] FIG. 2 illustrates one embodiment of electroplater according
to one embodiment of the present invention.
[0010] FIG. 3 illustrates a method of manufacturing a patterned
magnetic recording disk having an electrodeposited protection
layer, according to alternative embodiments of the present
invention.
DETAILED DESCRIPTION
[0011] Embodiments of the apparatus and methods are described
herein with reference to figures. However, particular embodiments
may be practiced without one or more of these specific details, or
in combination with other known methods, materials, and
apparatuses. In the following description, numerous specific
details are set forth, such as specific materials, dimensions and
processes parameters etc. to provide a thorough understanding. In
other instances, well-known manufacturing processes and equipment
have not been described in particular detail to avoid unnecessarily
obscuring the claimed subject matter. Reference throughout this
specification to "an embodiment" means that a particular feature,
structure, material, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
invention. Thus, the appearances of the phrase "in an embodiment"
in various places throughout this specification are not necessarily
referring to the same embodiment. Furthermore, the particular
features, structures, materials, or characteristics may be combined
in any suitable manner in one or more embodiments.
[0012] Embodiments of a method of electro-depositing a coating to
reside in the recessed areas (grooves) of a patterned magnetic film
are described. Electro-deposition of the coating in these
topographical grooves may be performed in order to passivate the
surfaces of these patterned grooves and prevent corrosion. In one
particular embodiment, such a coating layer is only
electro-deposited in the patterned grooves so that no additional
spacing loss is added to the top magnetic surface. In one
embodiment, depending on the coating layer thickness, the effect on
head flyability can also be mitigated by either partially or
completely filling the grooves to planarize the media. Improved
corrosion performance as well as flyability of the patterned media
may result from embodiments of the invention discussed herein.
[0013] In one embodiment, the electro-deposition process is
performed after the features have been etched by some means into
the media layers but before a mask layer is stripped so that only
the exposed conductive surfaces are the recessed features.
Consequently, material is only deposited in the recessed areas
(i.e., grooves) of the patterned magnetic layers(s) during the
electro-deposition process. After depositing the first coating in
the etched features, the masking layer is then stripped and second
protection layer (e.g., DLC film) can be deposited over the entire
surface of the patterned magnetic layer(s). As a result, the
recessed regions of the pattern will have two layers of protection
(i.e., electro-deposited film and vacuum deposited DLC) while the
non-recessed regions (i.e., lands) of the pattern will have only
the second protection layer (e.g., the DLC film).
[0014] As one of ordinary skill in the art will appreciate,
different deposition methods may provide distinct material
properties of the deposited layer. For example, one of ordinary
skill in the art would understand CVD carbon to have material
properties that are distinct from PVD carbon. Thus, a CVD carbon
layer would not be considered structurally equivalent to a PVD
carbon layer. As another example, a DLC film formed by a CVD method
is denser and harder than a DLC film formed by a sputtering method.
ALD is similar in chemistry to CVD, except that the ALD reaction
breaks the CVD reaction into two half-reactions, keeping precursor
materials separate during the reaction. A layer produced by electro
deposition has different material properties than a layer of
produced by ALD. As such, embodiments of the deposition method may
be discussed herein at times in reference to the physical
properties of a layer produced by the particular deposition method
as well as a description of the deposition process. In one
embodiment, the electrodeposited layer may have a crystalline
structure. Alternatively, the electrodeposited layer may have an
amorphous structure.
[0015] FIG. 1 is a conceptual illustration of the manufacturing
method 100 and resulting disk 205 structure of a patterned magnetic
recording disk, according to embodiments of the present invention.
Embodiments of the method of the present invention begin after
patterning of the magnetic layer(s) of a DTM disk. The patterning
may be accomplished by any one of several means (e.g., imprint
lithography, e-beam lithography, ion beam etching, reactive ion
etching, sputter etching, etc.) that are well known in the art;
accordingly, a detailed discussion is not provided. After
patterning of the magnetic layer(s) 112, a mask (e.g., resist)
layer 111 may remain above the lands of the pattern. In embodiments
where a mask layer does not remain after patterning of layer(s),
the method 100 includes the deposition and etching of a mask layer
to form openings above the grooves 113 of the magnetic layer(s) as
illustrated in the FIG. 1. The deposition and etching of a mask
layer is known in the art; accordingly, a detailed discussion is
not provided herein.
[0016] After the patterned magnetic layer(s) 112 and mask layer 111
have been provided, operation 110, the method 100 then proceeds
with electro-depositing a protection layer 123 within the grooves
113 of the patterned magnetic layer(s) 112, operation 120. Next,
mask layer 111 is removed, operation 130, followed by the
depositing of a second protection layer 145 over both the grooves
113 and lands 114 of the pattered magnetic layer(s) 112, step 140.
Further details of each of the operations of FIG. 1 are provided
below.
[0017] FIG. 2 illustrates one embodiment of electroplater 200 that
may be used in the electrodeposition operation 120 according to one
embodiment of the present invention. Electroplater 200 includes a
power supply 210 coupled to a disk carrier 220 and a plating tank
230, containing a plating bath 235, to provide an electric current
flow 211 in order to electroplate the first protection layer on the
patterned magnetic recording layer. Contact pins 225 are used to
provide electrical contact to the disk 205. In this particular
embodiment, disk 205 is held in the tank upside down by the disk
carrier 220.
[0018] In the electro-deposition process, the disk 205 as a work
piece is made into either an anode or a cathode depending on the
material to be deposited. A wide variety of materials can be
electrodeposited into the recessed areas of the magnetic recording
pattern including both metals and insulators. The materials which
can be electro-deposited in this fashion include, for example,
metals such as Au or silicates such as sodium silicate
(Na.sub.2SiO.sub.3), potassium silicate (K.sub.2SiO.sub.3). In one
embodiment, the deposited film may be a cross-linked silicate
(silica) film free of sodium or potassium. In the case of sodium
silicate, the electro-deposited film can then be converted to
silica by baking the coating after deposition, as illustrated by
operation 120 in FIG. 1.
[0019] In alternative embodiments, other metallic materials such as
aluminum (Al), gold (Au), chromium (Cr), ruthenium (Ru), platinum
(Pt), rhodium (Rh) and Copper (Cu) may be used. In general, metals
are not magnetically sensitive and provide good adhesion, corrosion
resistance and mechanical strength can also be employed. In yet
other embodiments, aluminates can also be used similarly as
silicate to be electro chemically deposited to the recessed areas
113. It should be noted that alloys can also be employed for
formation of the first protection layer 123. In addition, multiple
materials can also be electro-deposited in sequence to obtain
desired adhesion, corrosion resistance, and mechanical
properties.
[0020] When metallic materials are to be deposited into the grooves
113, the disk 205 is made a cathode and the tank electrode 240 is
made an anode. When silicates or aluminates are to be used, the
disk 205 is made an anode and the tank electrode 240 is made a
cathode. In one embodiment, the electro deposition is carried out
in a DC mode. In alternative embodiments, other plating modes may
be used, for example, a positively pulsed mode, or a reversely
pulsed mode (positive and negative). It should be noted that other
types and configurations of electroplaters may be used in
alternative embodiments of the present invention. Electroplating
equipment is known in the art; accordingly, a further discussion is
not provided herein. In one embodiment, the electrodeposition
operation may be performed using electroless plating
techniques.
[0021] The thickness of the first protection layer 123 can be
controlled so that the groove 113 depth can be controlled to render
the disk good flyability as well as good corrosion resistance. In
the case of the metal coatings, relatively thick coatings can be
achieved to even planarize the patterned features. In the case of
silicates or aluminates, the coating thickness is self-limiting
because the coating becomes non-conductive after a few nm and the
deposition process stops.
[0022] Parameters such as electroplating bath composition,
temperature, pH, voltage, pulse time and frequency (if pulsed),
deposition time, etc all should be controlled to obtain optimum
film properties. In order to limit the deposited film into grooves,
the resist on the land area is non-conductive according to one
embodiment. This can be done through controlling the resist
thickness or selecting resist of high electrical resistance.
[0023] FIG. 3 illustrates a method 300 of manufacturing a patterned
magnetic recording disk having an electrodeposited protection
layer, according to alternative embodiments of the present
invention. In one embodiment, one or more rinse operations,
operation 125, (e.g., with water) may follow the electro-deposition
operation 120 to clean the disk 205 free of possible loose deposits
in the electrolytes. In one embodiment, an annealing operation 126
may be performed before the final stripping of mask layer in
operation 130 to improve on the adhesion and mechanical properties
of the electro deposited films. Annealing should not be too severe
to hinder the final resist stripping operation. Rinse and annealing
operations are known in the art; accordingly, detailed discussions
of such operations are not provided.
[0024] Referring to both FIGS. 1 and 3, in operation 140, another,
second protective film 145 may be deposited over the
electro-deposited layer 123. In one embodiment, such additional
protective layer 145 is vacuum deposited DLC film. In such vacuum
deposited embodiments, the DLC film may be deposited with processes
such as, but not limited to, ion beam deposition (IBD), physical
vapor deposition (PVD), or chemical vapor deposition (CVD), such as
low pressure (LP) CVD or plasma enhanced (PE) CVD. In a particular
embodiments, the DLC film may be bi-layer formed. In alternative
embodiments, other materials may be used for the second protection
layer 145, for example, a nitride film, an oxide film such as
SiO.sub.2 film, etc.
[0025] Embodiments of the methods described above may be used to
fabricate a DTR perpendicular magnetic recording (PMR) disk having
a soft magnetic film disposed above a substrate. The soft magnetic
film may be composed of a single soft magnetic underlayer (SUL) or
multiple soft magnetic underlayers having interlayer materials,
such as ruthenium (Ru), disposed there between. In particular
embodiments, both sides of the substrate may be processed, in
either simultaneous or consecutive fashion, to form disks with
double sided DTR patterns.
[0026] The terms "over," "under," "between," and "on" as used
herein refer to a relative position of one layer with respect to
other layers. As such, for example, one layer deposited or disposed
over or under another layer may be directly in contact with the
other layer or may have one or more intervening layers. Moreover,
one layer deposited or disposed between layers may be directly in
contact with the layers or may have one or more intervening layers.
In contrast, a first layer "on" a second layer is in contact with
that second layer. Additionally, the relative position of one layer
with respect to other layers is provided assuming the initial
workpiece is a starting substrate and the subsequent processing
deposits, modifies and removes films from the substrate without
consideration of the absolute orientation of the substrate. Thus, a
film that is deposited on both sides of a substrate is "over" both
sides of the substrate.
[0027] Although these embodiments have been described in language
specific to structural features and methodological acts, it is to
be understood that the invention defined in the appended claims is
not necessarily limited to the specific features or acts described
in particular embodiments. The specific features and acts disclosed
are to be understood as particularly graceful implementations of
the claimed invention in an effort to illustrate rather than limit
the present invention.
* * * * *