U.S. patent application number 15/016149 was filed with the patent office on 2017-08-10 for suspension pad for head-gimbal assembly that inhibits formation of an inter-pad solder bridge.
The applicant listed for this patent is HGST Netherlands B.V.. Invention is credited to Yuhsuke Matsumoto, Kenichi Murata, Hiroyasu Tsuchida, Masafumi Umeda.
Application Number | 20170229140 15/016149 |
Document ID | / |
Family ID | 59410755 |
Filed Date | 2017-08-10 |
United States Patent
Application |
20170229140 |
Kind Code |
A1 |
Murata; Kenichi ; et
al. |
August 10, 2017 |
SUSPENSION PAD FOR HEAD-GIMBAL ASSEMBLY THAT INHIBITS FORMATION OF
AN INTER-PAD SOLDER BRIDGE
Abstract
Devices including a suspension pad shape and layout that avoids
shorts caused by solder bridging during coupling of leads thereto.
One embodiment includes a plurality of slider pads and a plurality
of suspension pads being generally aligned with the slider pads. A
conductive material electrically couples each of the suspension
pads to the slider pad aligned therewith. At least one of the
suspension pads is characterized as follows. The suspension pad has
a proximal edge positioned closest to the associated slider pad, a
distal edge positioned opposite the proximal edge, and side edges
extending between the proximal and distal edges. At least a portion
of the suspension pad tapers toward the proximal edge.
Inventors: |
Murata; Kenichi; (Ebina,
JP) ; Matsumoto; Yuhsuke; (Fujisawa, JP) ;
Umeda; Masafumi; (Fujisawa, JP) ; Tsuchida;
Hiroyasu; (Fujisawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HGST Netherlands B.V. |
Amsterdam |
|
NL |
|
|
Family ID: |
59410755 |
Appl. No.: |
15/016149 |
Filed: |
February 4, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G11B 5/4826 20130101;
G11B 5/4853 20130101; G11B 5/4846 20130101 |
International
Class: |
G11B 5/48 20060101
G11B005/48 |
Claims
1. A system, comprising: a plurality of slider pads; a plurality of
suspension pads being generally aligned with the slider pads; and a
conductive material electrically coupling each of the suspension
pads to the slider pad aligned therewith, at least one of the
suspension pads being characterized as follows: the suspension pad
having a proximal edge positioned closest to the associated slider
pad, a distal edge positioned opposite the proximal edge, and side
edges extending between the proximal and distal edges, wherein at
least a portion of the suspension pad tapers toward the proximal
edge, and wherein a first vertex is defined along a point of the
side edge positioned closest to a second of the slider pads that is
positioned immediately adjacent the slider pad aligned with the
suspension pad, wherein a first distance is defined between the
vertex and the second slider pad, wherein a virtual vertex is
defined at an intersection of perpendicular lines extending along
the proximal edge and the side edge closest to the second slider
pad, wherein a second distance is defined from the virtual vertex
to the second slider pad, wherein the first distance is greater
than the second distance, and wherein a difference between the
first distance and the second distance is at least 15% of a
smallest width of the slider pad associated with the suspension
pad.
2. (canceled)
3. A system, comprising: a plurality of slider pads; a plurality of
suspension pads being generally aligned with the slider pads; and a
conductive material electrically coupling each of the suspension
pads to the slider pad aligned therewith, at least one of the
suspension pads being characterized as follows: the suspension pad
having a proximal edge positioned closest to the associated slider
pad, a distal edge positioned opposite the proximal edge, and side
edges extending between the proximal and distal edges, wherein at
least a portion of the suspension pad tapers toward the proximal
edge, wherein a vertex is defined along a point of the side edge
positioned closest to a second of the slider pads that is
positioned immediately adjacent the slider pad aligned with the
suspension pad, wherein a first distance is defined between the
vertex and the second slider pad, wherein a virtual vertex is
defined at an intersection of perpendicular lines extending along
the proximal edge and the side edge closest to the second slider
pad, wherein a second distance is defined from the virtual vertex
to the second slider pad, wherein the first distance is greater
than the second distance, and wherein a difference between the
first distance and the second distance is at least 15% of a width
between the vertex and a second vertex of the suspension pad
positioned along the side edge opposite the vertex.
4. The system as recited in claim 3, wherein the conductive
material is solder.
5. The system as recited in claim 3, wherein the conductive
material extends from faces of the slider pads that are oriented
orthogonally to faces of the suspension pads.
6. The system as recited in claim 3, wherein the side edge
positioned closest to a second of the slider pads is straight.
7. The system as recited in claim 3, wherein the side edge
positioned closest to a second of the slider pads is stepped.
8. The system as recited in claim 3, wherein the side edge
positioned closest to a second of the slider pads is curved.
9. The system as recited in claim 1, wherein both side edges of the
at least one suspension pad have taper portions that approach one
another toward the proximal edge.
10. The system as recited in claim 9, wherein each side edge is
straight therealong between the proximal and distal side edges.
11. The system as recited in claim 9, wherein each side edge is
stepped.
12. The system as recited in claim 9, wherein each side edge is
curved.
13. The system as recited in claim 1, wherein a distance between
the proximal edge of the at least one suspension pad and the slider
pad aligned therewith, measured in a direction parallel to a plane
of deposition of the suspension pad, is greater than 0.
14. The system as recited in claim 1, wherein the at least one
suspension pad extends to or below the associated slider pad.
15. The system as recited in claim 1, further comprising: a
magnetic medium; a drive mechanism for passing the magnetic medium
over the slider pads and suspension pads; and a controller
electrically coupled to the suspension pads.
16. A method of forming the system of claim 1, comprising: aligning
the slider pads with the suspension pads; and depositing the
conductive material.
17. The method as recited in claim 16, wherein the conductive
material is solder, wherein the solder is deposited by solder ball
deposition.
18. (canceled)
19. (canceled)
20. A product, comprising: a plurality of suspension pads arranged
along a substrate, at least one of the suspension pads being
characterized as follows: the suspension pad having a proximal edge
for positioning closest to an expected position of a first slider
pad to be electrically coupled to the suspension pad, a distal edge
positioned opposite the proximal edge, and side edges extending
between the proximal and distal edges, wherein at least a portion
of the suspension pad tapers toward the proximal edge, wherein a
vertex is defined along a point of the side edge positioned closest
to the expected position of a second slider pad positioned
immediately adjacent the expected position of the first slider pad,
wherein a first distance is defined between the vertex and the
expected position of the second slider pad, wherein a virtual
vertex is defined at an intersection of perpendicular lines
extending along the proximal edge and the side edge closest to the
expected position of the second slider pad, wherein a second
distance is defined from the virtual vertex to the expected
position of the second slider pad, wherein the first distance is
greater than the second distance, and wherein a difference between
the first distance and the second distance is at least 15% of a
width between the vertex and a second vertex of the suspension pad
positioned along the side edge opposite the vertex.
21. The product as recited in claim 20, wherein the side edge
positioned closest to the expected position of the second slider
pad is at least one of straight, stepped and curved.
22. The product as recited in claim 20, wherein both side edges of
at least some of the suspension pads have taper portions that
approach one another toward the proximal edge.
23. The product as recited in claim 20, further comprising: a
magnetic medium; a slider having slider pads electrically coupled
to the suspension pads; a drive mechanism for passing the magnetic
medium over the slider; and a controller electrically coupled to
the suspension pads.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to data storage systems, and
more particularly, this invention relates to a pad design that
inhibits formation of inter-pad solder bridges.
BACKGROUND
[0002] The heart of a computer is a magnetic hard disk drive (HDD)
which typically includes a rotating magnetic disk, a slider that
has read and write heads, a suspension arm above the rotating disk
and an actuator arm that swings the suspension arm to place the
read and/or write heads over selected data tracks on the rotating
disk. The suspension arm biases the slider into contact with the
surface of the disk when the disk is not rotating but, when the
disk rotates, air is swirled by the rotating disk adjacent an air
bearing surface (ABS) of the slider causing the slider to ride on
an air bearing a slight distance from the surface of the rotating
disk. When the slider rides on the air bearing the write and read
heads are employed for writing magnetic impressions to and reading
magnetic signal fields from the rotating disk. The read and write
heads are connected to processing circuitry that operates according
to a computer program to implement the writing and reading
functions.
[0003] The volume of information processing in the information age
is increasing rapidly. In particular, it is desired that HDDs be
able to store more information in their limited area and volume. A
technical approach to meet this desire is to increase the capacity
by increasing the recording density of the HDD. To achieve higher
recording density, further miniaturization of recording bits is
effective, which in turn typically requires the design of smaller
and smaller components.
[0004] The further miniaturization of the various components,
however, presents its own set of challenges and obstacles.
[0005] Moreover, the addition of electrical contact pads to a
slider to enable such technologies as Heat Assisted Magnetic
Recording (HAMR), Microwave Assisted Magnetic Recording (MAMR), and
others have led to a high density of electrical pads in close
proximity. This in turn creates problems such as increasing the
likelihood of a short between adjacent pads, especially when using
solder.
SUMMARY
[0006] A system according to one embodiment includes a plurality of
slider pads, a plurality of suspension pads generally aligned with
the slider pads, and a conductive material electrically coupling
each of the suspension pads to the slider pad aligned therewith. At
least one of the suspension pads is characterized as follows. The
suspension pad has a proximal edge positioned closest to the
associated slider pad, a distal edge positioned opposite the
proximal edge, and side edges extending between the proximal and
distal edges. At least a portion of the suspension pad tapers
toward the proximal edge, the tapered portion of the suspension pad
being defined between "taper portions" of the side edges.
[0007] A product according to one embodiment includes a plurality
of suspension pads arranged along a substrate. At least one of the
suspension pads is characterized as follows. The suspension pad has
a proximal edge for positioning closest to an expected position of
a first slider pad to be electrically coupled to the suspension
pad, a distal edge positioned opposite the proximal edge, and side
edges extending between the proximal and distal edges. At least a
portion of the suspension pad tapers toward the proximal edge.
[0008] Any of these embodiments may be implemented in a magnetic
data storage system such as a disk drive system, which may include
a magnetic head, a drive mechanism for passing a magnetic medium
(e.g., hard disk) over the magnetic head, and a controller
electrically coupled to the magnetic head.
[0009] Other aspects and advantages of the present invention will
become apparent from the following detailed description, which,
when taken in conjunction with the drawings, illustrate by way of
example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For a fuller understanding of the nature and advantages of
the present invention, as well as the preferred mode of use,
reference should be made to the following detailed description read
in conjunction with the accompanying drawings.
[0011] FIG. 1 is a drawing of a magnetic disk drive system,
according to one embodiment.
[0012] FIG. 2 is an enlarged perspective view of the portion of the
Head-Gimbal Assembly (HGA) enclosed by circle 2 of FIG. 1.
[0013] FIG. 3 is a top-down view of a plurality of slider pads and
a plurality of suspension pads taken from circle 3 of FIG. 2.
[0014] FIG. 4 is a chart depicting various suspension pad designs
and results of an experiment using the suspension pad designs.
[0015] FIG. 5A is a top-down view of the slider pad and a
suspension pad which extends below the bottom of the slider
according to one embodiment.
[0016] FIG. 5B is a top-down view of a suspension pad that extends
to the proximal edge of the slider pad according to one
embodiment.
[0017] FIG. 6 is a representative view showing various suspension
pad designs according to various embodiments.
[0018] FIG. 7 is a representative view illustrating the distance
relationship of a shaped suspension pad to the adjacent slider pad
according to one embodiment.
[0019] FIG. 8 is a flow chart of a method of forming a magnetic
data storage system according to one embodiment.
DETAILED DESCRIPTION
[0020] The following description is made for the purpose of
illustrating the general principles of the present invention and is
not meant to limit the inventive concepts claimed herein. Further,
particular features described herein can be used in combination
with other described features in each of the various possible
combinations and permutations.
[0021] Unless otherwise specifically defined herein, all terms are
to be given their broadest possible interpretation including
meanings implied from the specification as well as meanings
understood by those skilled in the art and/or as defined in
dictionaries, treatises, etc.
[0022] It must also be noted that, as used in the specification and
the appended claims, the singular forms "a," "an" and "the" include
plural referents unless otherwise specified.
[0023] The following description discloses several preferred
embodiments of disk-based storage systems and/or related systems
and methods, as well as operation and/or component parts thereof.
Particularly, various embodiments implement uniquely shaped
suspension pads that inhibit formation of solder bridges, thereby
preventing shorting on electronics such as HGAs.
[0024] In one general embodiment, a system includes a plurality of
slider pads, a plurality of suspension pads generally aligned with
the slider pads, and a conductive material electrically coupling
each of the suspension pads to the slider pad aligned therewith. At
least one of the suspension pads is characterized as follows. The
suspension pad has a proximal edge positioned closest to the
associated slider pad, a distal edge positioned opposite the
proximal edge, and side edges extending between the proximal and
distal edges. At least a portion of the suspension pad tapers
toward the proximal edge.
[0025] In another general embodiment, a product includes a
plurality of suspension pads arranged along a substrate. At least
one of the suspension pads is characterized as follows. The
suspension pad has a proximal edge for positioning closest to an
expected position of a first slider pad to be electrically coupled
to the suspension pad, a distal edge positioned opposite the
proximal edge, and side edges extending between the proximal and
distal edges. At least a portion of the suspension pad tapers
toward the proximal edge.
[0026] With reference now to FIG. 1, in accordance with various
embodiments of the present invention, a plan view of a hard-disk
drive (HDD) 101 is shown. HDD 101 includes a HGA 110 with a
suspension pad, for example, suspension pad 220 (see FIG. 2),
having a form that is configured to inhibit formation of an
inter-pad solder bridge HDD 101 includes at least one such HGA 110.
The HGA 110 includes a gimbal 110e, a slider 110a, and a plurality
of suspension pads 220 (see FIG. 2). The slider 110a includes a
magnetic head, typically at a distal end thereof. The magnetic head
may include one or more transducers, such as a magnetic reader, a
magnetic writer, a near field transducer for heating the
magnetic-recording disk 120, etc. HGA 110 further includes a
suspension 110b attached to the slider 110a. The slider 110a is
attached at the distal end of the load beam 110c via a gimbal 110e,
which is attached to the load beam 110c. The HGA 110 may also
include a tongue 110d, which is used in loading and unloading the
slider 110a from a load-unload ramp structure 190.
[0027] HDD 101 also includes at least one magnetic-recording disk
120 rotatably mounted on a spindle 126 and a drive mechanism such
as a spindle motor (not shown) mounted in a disk-enclosure base 168
and attached to the spindle 126 for rotating the magnetic-recording
disk 120. The magnetic-recording disk 120, or a plurality (not
shown) of magnetic-recording disks, may be affixed to the spindle
126 with a disk clamp 128. The disk clamp 128 is provided with
fastener holes, for example, fastener hole 130, and clamps the
magnetic-recording disk 120, or magnetic recording disks (not
shown), to a hub (not shown) with fasteners, of which fastener 131
is an example.
[0028] HDD 101 further includes an actuator arm 134 attached to HGA
110, a carriage 136, a voice-coil motor (VCM) that includes an
armature 138 including a voice coil 140 attached to the carriage
136; and a stator 144 including a voice-coil magnet (not shown);
the armature 138 of the VCM is attached to the carriage 136 and is
configured to move the actuator arm 134 and HGA 110 to access
portions of the magnetic-recording disk 120, as the carriage 136 is
mounted on a pivot-shaft 148 with an interposed pivot-bearing
assembly 152.
[0029] With further reference to FIG. 1, in accordance with one or
more embodiments of the present invention, electrical signals, for
example, current to the voice coil 140 of the VCM, and write
signals to and read signals from the magnetic-recording head of the
slider 110a, are provided by a flexible cable 156. Interconnection
between the flexible cable 156 and the magnetic-recording head may
be provided by an arm-electronics (AE) module 160, which may have
an on-board pre-amplifier for the read signal, as well as other
read-channel and write-channel electronic components. The flexible
cable 156 is coupled to an electrical-connector block 164, which
provides electrical communication through electrical feedthroughs
(not shown) provided by the disk-enclosure base 168. The
disk-enclosure base 168, in conjunction with an HDD cover (not
shown), provides a sealed protective disk enclosure for the
information storage components of HDD 101.
[0030] With further reference to FIG. 1, in accordance with one or
more embodiments, other electronic components (not shown),
including a disk controller and servo electronics including a
digital-signal processor (DSP), provide electrical signals to the
spindle motor, the voice coil 140 and the slider 110a. The
electrical signal provided to the spindle motor enables the spindle
motor to spin providing a torque to the spindle 126 which is in
turn transmitted to the magnetic-recording disk 120 that is affixed
to the spindle 126 by the disk clamp 128; as a result, the
magnetic-recording disk 120 spins in direction 172. The spinning
magnetic-recording disk 120 creates an airflow thereabove, and a
self-acting air bearing on which the media facing side, also
referred to as an air-bearing surface (ABS), of the slider 110a
rides so that the slider 110a flies in proximity with the recording
surface of the magnetic-recording disk 120. The electrical signal
provided to the voice coil 140 of the VCM enables the
magnetic-recording head of the slider 110a to access a track 176 on
which information is recorded. As used herein, "access" is a term
of art that refers to operations in seeking the track 176 of the
magnetic-recording disk 120 and positioning the magnetic-recording
head on the track for both reading data from, and writing data to,
the magnetic-recording disk 120. The armature 138 of the VCM swings
through an arc 180 which enables HGA 110 attached to the armature
138 by the actuator arm 134 to access various tracks on the
magnetic-recording disk 120. Information is typically stored on the
magnetic-recording disk 120 in a plurality of concentric tracks
(not shown) arranged in sectors on the magnetic-recording disk 120,
for example, sector 184. Correspondingly, each track 176 is
composed of a plurality of sectored track portions, for example,
sectored track portion 188. Each sectored track portion 188 may
include recorded data and a header containing a servo-burst-signal
pattern, for example, an ABCD-servo-burst-signal pattern,
information that identifies the track 176, and error correction
code information. In accessing the track 176, the read element of
the magnetic-recording head reads the servo-burst-signal pattern
which provides a position-error-signal (PES) to the servo
electronics, which controls the electrical signal provided to the
voice coil 140 of the VCM, enabling the magnetic-recording head to
follow the track 176. Upon finding the track 176 and identifying a
particular sectored track portion 188, the magnetic-recording head
may read data from the track 176, write data to the track 176, or
both, depending on instructions received by the disk controller
from an external agent, for example, a processor of a computer
system.
[0031] Also as shown in FIG. 1, a reference circle 2 is provided to
indicate the portion of the HGA 110 subsequently described in the
discussion of FIG. 2.
[0032] The above description of a magnetic disk storage system, and
the accompanying illustration of FIG. 1 is for representation
purposes only. It should be apparent that disk storage systems may
contain a large number of disks and actuators, and each actuator
may support a number of sliders.
[0033] An interface may also be provided for communication between
the disk drive and a host (integral or external) to send and
receive the data and for controlling the operation of the disk
drive and communicating the status of the disk drive to the host,
all as will be understood by those of skill in the art.
[0034] Regarding a magnetic head, an inductive write portion
therein includes a coil layer embedded in one or more insulation
layers (insulation stack), the insulation stack being located
between first and second pole piece layers. A gap may be formed
between the first and second pole piece layers by a gap layer at an
air bearing surface (ABS) of the write portion. The pole piece
layers may be connected at a back gap. Currents are conducted
through the coil layer, which produce magnetic fields in the pole
pieces. The magnetic fields fringe across the gap at the ABS for
the purpose of writing bits of magnetic field information in tracks
on moving media, such as in tracks on a rotating magnetic disk.
[0035] Except as otherwise described herein with reference to the
various inventive embodiments, the various components of the
structures of FIG. 1, and of other embodiments disclosed herein,
may be of conventional material(s), design, and/or fabricated using
conventional techniques, as would become apparent to one skilled in
the art upon reading the present disclosure.
[0036] FIG. 2 is an enlarged perspective view of the portion of the
HGA enclosed by circle 2 of FIG. 1, detailing a plurality of
suspension pads in communication with a plurality of head-slider
pads at the trailing edge of the slider joined together in pairs by
a plurality of solder bonds without the formation of inter-pad
solder bridges, in accordance with one or more embodiments.
[0037] FIG. 2 shows in detail a plurality of suspension pads 220
generally aligned with and in communication with a plurality of
slider pads 210 at the trailing edge of the slider 110a joined
together in pairs by a plurality of bonds of conductive material,
e.g., solder bonds 230 without the formation of inter-pad solder
bridges. A line on either side of which the plurality of suspension
pads 220 and the plurality of slider pads 210 are about
symmetrically arranged for interconnection is indicated by line
A-A. As shown in FIG. 2, the slider 110a. includes a magnetic head
110a-2 coupled with the slider body 110a-1, and a plurality of
slider pads 210. The magnetic head 110a-2 may include a write
element 110a-21 configured for writing data to a magnetic-recording
disk, and/or a read element 110a-22 configured for reading data
from the magnetic-recording disk. Each of the suspension pads 220
is coupled with an associated slider pad 210 by a respective solder
bond 230.
[0038] Except where otherwise specified, the various component
parts of system 101 may be of conventional construction and/or
design, and fabricated using conventional processes and
techniques.
[0039] Note that FIG. 2 shows six suspension/slider pad pairs. As
noted above, the number of connections between a magnetic head and
the suspension is increasing as new technology such as MAMR and
MIMO are introduced. Consequently, the spacing between neighboring
pads becomes narrow, resulting in solder bridge failure due to
formation of inter-pad solder bridging between adjacent pads.
[0040] Accordingly, various embodiments presented herein include
suspension pads 220 having a shape that inhibits formation of
solder bridging with laterally adjacent pads when used in
conjunction with conventional solder ball coupling. Moreover,
counterintuitively, the proposed suspension pads 220 result in
formation of fewer solder bridges than narrower suspension pads
having greater pad-to-pad spacing therebetween.
[0041] Referring to FIG. 3, there is shown a top-down view, taken
from circle 3 of FIG. 2, of a plurality of slider pads 210 and a
plurality of suspension pads 220 that are generally aligned with
the slider pads. The conductive material electrically coupling each
of the slider pads to the slider pad aligned therewith is shown in
the path indicated by the curved dotted lines. Again, while six
pairs of pads are shown, the number of pairs of pads may be higher
or lower. For example, various embodiments may have 8, 10, 12, 14,
or more pairs of pads.
[0042] At least one of the suspension pads, and preferably all of
the suspension pads, are characterized as having the following
features. In an exemplary embodiment shown, each suspension pad has
a proximal edge 302 positioned closest to the associated slider pad
aligned therewith, a distal edge 304 positioned opposite the
proximal edge, and side edges 306 extending between the proximal
and distal edges. At least a portion of the suspension pad tapers
toward the proximal edge 302. For example, at least one, and
preferably both, of the side edges of the suspension pad has a
taper portion 308 along the portion of the suspension pad, thereby
defining a portion of the suspension pad that tapers toward the
proximal edge 302. As discussed in more detail below, the tapering
may include straight sections, bending or curving sections, stepped
sections, and combinations thereof. There may be no change in width
of the slider pad 210 therealong.
[0043] In preferred embodiments, a vertex V is defined along the
taper portion of one or both side edges that define the tapered
portion of the suspension pad, the vertex being a point along the
side edge (taper portion) positioned closest to a second of the
slider pads that is positioned diagonally from the suspension pad,
and positioned immediately adjacent the slider pad that is aligned
with the suspension pad. A first distance J is defined between the
vertex and the nearest point on the second slider pad.
[0044] A virtual vertex VV is defined at an intersection of
perpendicular imaginary lines 310, 312 extending along the proximal
edge and the side edge closest to the second slider pad,
respectively. A second distance I is defined from the virtual
vertex to the nearest point on the second slider pad. By making the
first distance greater than the second distance (J>I), formation
of solder bridging to laterally adjacent pads is inhibited,
especially when using conventional solder ball coupling to form the
conductive path between the orthogonally-oriented faces of the
pads. If the extrusion is large, as seen when distance J is not
larger but equal to distance I, then the molten solder ball is at
risk of touching the adjacent suspension pad thereby causing a
solder short connection.
[0045] Preferably, effective distance K defined as the difference
between the distance J and the distance I is at least 15% of a
smallest width (W.sub.SL) of the associated slider pad, and
preferably at least 15% of a smallest width of the smallest slider
pad.
[0046] Without wishing to be bound by any theory, it is believed
that addition of taper portions to one or both side edges of the
suspension pads near the proximal edge thereof reduces the maximum
amount of lateral solder extrusion upon application of the molten
solder ball to the pads.
[0047] Moreover, referring to FIG. 4, while performing
experimentation to confirm the foregoing, the inventors
surprisingly found that using suspension pads having the
aforementioned J>I distance relationship resulted in the lowest
maximum solder extrusion of the designs studied under otherwise
identical conditions. This result was not expected or predictable.
Rather, the inventors expected the "Wide," "Narrow-end" and
"Hole-end" designs (FIG. 4) to mitigate the solder extrusion to
eliminate solder bridging. In contrast, what they found was that
the Narrow-end design provided a significantly lower solder
extrusion than any other design. Narrow-end suspension pad design
performed best from the view point of solder extrusion. These
observations were obtained by high speed camera that documented the
extrusion of molten solder when the molten solder landed on the
suspension pad.
[0048] FIG. 4 sets forth the suspension pad designs and results of
the aforementioned experiment. In the experiment, an identical
solder ball deposition process was performed on various suspension
pad designs, while the slider pad design was the same in all runs.
As shown, the various pad designs tested were Narrow, Narrow-end,
Medium, Hole-end, and Wide. As shown in the chart above the designs
in FIG. 4, the Narrow-end having the J>I distance relationship
resulted in the lowest maximum amount of solder extrusion, which is
defined as the maximum extent that the edge of the solder extends
laterally beyond the side edge of the pad on which it is extruded
at any point during the solder ball deposition process.
[0049] Referring again to FIG. 3, in the example shown, a distance
C is defined as the clearance between the proximal edge 302 of each
suspension pad 220 and the slider pad 210 aligned therewith,
measured in a direction parallel to a plane of deposition of the
suspension pad. The distance C is greater than 0 mm in some
approaches. In other embodiments, one or more of the suspension
pads may extend to and/or below the slider pad. In other words, the
clearance C is zero or negative, e.g., as shown in FIGS. 5A and
5B.
[0050] FIGS. 5A and 5B depict alternate embodiments. As an option,
the present embodiments may be implemented in conjunction with
features from any other embodiment listed herein, such as those
described with reference to the other FIGS. Of course, however,
such embodiments and others presented herein may be used in various
applications and/or in permutations which may or may not be
specifically described in the illustrative embodiments listed
herein. Further, the embodiments presented herein may be used in
any desired environment.
[0051] FIG. 5A depicts an embodiment where the suspension pad 220
extends below the slider pad 210. FIG. 5B depicts an embodiment
where the suspension pad 220 extends to the edge of the slider pad
210. In both FIGS. 5A and 5B, a first distance J is defined from
the vertex as shown as the corner of the suspension pad 220 where
the suspension pad edge meets the edge of the slider pad 210 to the
nearest point on the second slider pad. A second distance I is
defined from the virtual vertex to the nearest point on the second
slider pad. Effective distance K is defined as difference between
first distance J and second distance I wherein the first distance
is greater than the second distance (J>I).
[0052] Referring to FIGS. 3, 5A and 5B, the width W.sub.SU of the
distal end of the suspension pad is preferably as wide or wider
than the slider pad, though could be slightly narrower than the
corresponding slider pad, as long as the proper relationship
between the first and second distances I, J is maintained
(J>I).
[0053] As shown in FIG. 3, all of the suspension pads have the same
shape in that exemplary embodiment. Note that the particular shape
of the suspension pad may vary from that shown in FIG. 3. For
example, the tapering of the suspension pads may include straight
sections, bending or curving sections, stepping sections, and
combinations thereof. FIG. 6 illustrates some of the possible
shapes that may be implemented in various embodiments. Accordingly,
various approaches may include arrays of suspension pads having a
profile (shape) similar to any of those shown in FIG. 6, or other
shapes providing the proper relationship between the first and
second distances I, J.
[0054] Moreover, while all of the suspension pads may have similar
profiles in some approaches, various embodiments may have
suspension pads in various combinations of different shapes, e.g.,
a combination of the profiles shown in FIG. 6. In one example, two
different profiles may be arranged in an alternating fashion such
that every other suspension pad may have one or both taper portions
while the alternating suspension pads may be more rectangular.
Thus, any combination of suspension pad shapes may be used in the
various permutations and variations of embodiments.
[0055] FIG. 7 depicts a shape profile of a suspension pad in
accordance with one embodiment. As an option, the present shape
profile may be implemented in conjunction with features from any
other embodiment listed herein, such as those described with
reference to the other FIGS. 2-6. Of course, however, such a shape
profile of a suspension pad and others presented herein may be used
in various applications and/or in permutations which may or may not
be specifically described in the illustrative embodiments listed
herein. Further, the shape profile of a suspension pad presented
herein may be used in any desired environment.
[0056] The vertex of the suspension pad 220 shown in FIG. 7 is
defined as the point along the curve or stepped portion between the
side edges along line 312 and the proximal edge 302 that is nearest
to the expected position of the second slider pad 210, such that
the first distance J is defined between the vertex and the nearest
point of the expected position of the second slider pad 210. The
second distance I is defined from the virtual vertex VV, at the
intersection of imaginary lines 310, 312, to the nearest point of
the expected position of the second slider pad such that the first
distance is greater than the second distance (J>I).
[0057] The suspension pads and slider pads may be constructed of
any suitable conductive material. Illustrative materials include,
but are not limited to, gold, copper, nickel, and aluminum. The
solder may be of a type known in the art.
[0058] FIG. 8 shows a method 800 for forming a magnetic data
storage system, in accordance with various embodiments. As an
option, the present method 800 may be implemented to construct
structures such as those shown in FIGS. 1-7. Of course, however,
this method 800 and others presented herein may be used to form
magnetic structures for a wide variety of devices and/or purposes
which may or may not be related to magnetic recording. Further, the
methods presented herein may be carried out in any desired
environment. It should also be noted that any aforementioned
features may be used in any of the embodiments described in
accordance with the various methods.
[0059] With reference to FIG. 8, operation 802 includes aligning
the slider pads with the suspension pads using known techniques,
followed by depositing the conductive material in operation 804. A
preferred embodiment includes depositing a conductive material such
as solder by solder ball deposition.
[0060] It should be noted that methodology presented herein for at
least some of the various embodiments may be implemented, in whole
or in part, in computer hardware, software, by hand, using
specialty equipment, etc. and combinations thereof.
[0061] Moreover, any of the structures and/or steps may be
implemented using known materials and/or techniques, as would
become apparent to one skilled in the art upon reading the present
specification.
[0062] The inventive concepts disclosed herein have been presented
by way of example to illustrate the myriad features thereof in a
plurality of illustrative scenarios, embodiments, and/or
implementations. It should be appreciated that the concepts
generally disclosed are to be considered as modular, and may be
implemented in any combination, permutation, or synthesis thereof.
In addition, any modification, alteration, or equivalent of the
presently disclosed features, functions, and concepts that would be
appreciated by a person having ordinary skill in the art upon
reading the instant descriptions should also be considered within
the scope of this disclosure.
[0063] While various embodiments have been described above, it
should be understood that they have been presented by way of
example only, and not limitation. Thus, the breadth and scope of an
embodiment of the present invention should not be limited by any of
the above-described exemplary embodiments, but should be defined
only in accordance with the following claims and their
equivalents.
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