U.S. patent application number 11/297767 was filed with the patent office on 2006-04-27 for system and method for improving hard drive actuator lead attachment.
Invention is credited to Can Hua Chen, Yiu Sing Ho, Guo Hong Lu, Yuan Neng Luo, Jeffery L. Wang, Liu Jun Zhang.
Application Number | 20060086772 11/297767 |
Document ID | / |
Family ID | 33136772 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060086772 |
Kind Code |
A1 |
Ho; Yiu Sing ; et
al. |
April 27, 2006 |
System and method for improving hard drive actuator lead
attachment
Abstract
A system and method are disclosed for improving hard drive
actuator lead attachment. In one embodiment, an actuator board is
coupled to an actuator flexible cable by a bonding agent, such as
an anisotropic conductive film (ACF). In one embodiment, an
actuator flexible cable is coupled to one or more actuator coil
leads, such as by solder bump bonding, and the flexible
cable/actuator coil coupling is embedded in an actuator frame, such
as by polymer injection molding.
Inventors: |
Ho; Yiu Sing; (Ma On Shan
Shatin, N.T., HK) ; Lu; Guo Hong; (Dongguan City,
CN) ; Chen; Can Hua; (Dongguan City, CN) ;
Luo; Yuan Neng; (Dongguan City, CN) ; Wang; Jeffery
L.; (Taipo, N.T., HK) ; Zhang; Liu Jun;
(Dongguan City, CN) |
Correspondence
Address: |
KENYON & KENYON;Suite 600
333 W. San Carlos Street
San Jose
CA
95110-2711
US
|
Family ID: |
33136772 |
Appl. No.: |
11/297767 |
Filed: |
December 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10741139 |
Dec 19, 2003 |
|
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11297767 |
Dec 7, 2005 |
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Current U.S.
Class: |
228/101 ;
G9B/5.15 |
Current CPC
Class: |
H05K 3/3447 20130101;
H05K 2201/10356 20130101; B23K 20/023 20130101; G11B 5/4846
20130101; H05K 3/323 20130101; B23K 2101/40 20180801; H05K 3/361
20130101; Y10T 29/49025 20150115; H05K 1/189 20130101 |
Class at
Publication: |
228/101 |
International
Class: |
A47J 36/02 20060101
A47J036/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 11, 2003 |
WO |
PCT/CN03/00256 |
Claims
1. A system for manufacturing a hard disc drive arm comprising: a
hard drive actuator board having at least one actuator pad to be
coupled to a flexible cable element having at least one flexible
cable pad by a bonding agent, wherein said bonding agent includes a
plurality of electrically conductive particles; said bonding agent
is to be compressed between said actuator board and said flexible
cable element; and a number of said particles is to form an
electrical path between said actuator pad and said flexible cable
pad.
2. The system of claim 1, wherein said flexible cable element is a
hard drive relay flexible cable.
3. The system of claim 1, wherein said bonding agent is anisotropic
conductive film (ACF).
4. The system of claim 1, wherein said electrically conductive
particles are silver.
5. The system of claim 1, wherein said electrically conductive
particles are silver-coated glass spheres.
6. The system of claim 1, wherein said electrically conductive
particles are to embed into said actuator pad and into said
flexible cable pad to form said electrical path.
7. The system of claim 1, wherein said hard drive actuator board is
to be positioned upon said flexible cable element for coupling by
pre-tacking said actuator board to said flexible cable element with
said bonding agent.
8. The system of claim 1, wherein said hard drive actuator board is
to be coupled to said flexible cable element by applying pressure
to said flexible cable element by a bonding tip to compress said
bonding agent between said actuator board and said flexible cable
element.
9. The system of claim 8, wherein said bonding tip is a heated
bonding tip and said bonding agent is to be heated by said bonding
tip for coupling said actuator board to said flexible cable
element.
10-18. (canceled)
19. A system for manufacturing a hard disc drive arm comprising: a
hard drive actuator board having at least one actuator pad to be
coupled to a flexible cable element having at least one flexible
cable pad by a bonding agent, wherein said bonding agent includes a
plurality of electrically conductive particles; said bonding agent
is to be compressed between said actuator board and said flexible
cable element; and a number of said particles is to form an
electrical path between said actuator pad and said flexible cable
pad.
20. A system for manufacturing a hard disc drive arm comprising: an
electrical lead of a hard drive actuator coil to be coupled to a
flexible cable pad of a flexible cable element, forming a coupling,
wherein at least a portion of said coupling is to be enclosed in a
polymer frame.
21. The system of claim 20, wherein said electrical lead is to be
coupled to said flexible cable pad by solder bonding.
22. The system of claim 20, wherein said electrical lead is
copper.
23. The system of claim 20, wherein said electrical lead is
gold-plated copper.
24. The system of claim 20, wherein said flexible cable pad is
copper.
25. The system of claim 20, wherein said flexible cable pad is
gold-plated copper.
26. The system of claim 20, wherein a mold is to surround said
portion of said coupling and polymer is to be injected into said
mold to form said polymer frame.
27-29. (canceled)
Description
BACKGROUND INFORMATION
[0001] The present invention relates to hard disk drives. More
specifically, the invention relates to a system and method for
improving the electrical connection of a hard drive actuator coil
lead.
[0002] FIG. 1 provides an illustration of a typical hard disk
drive. Hard disk drive storage devices typically include a rotating
disk 10 mounted for rotation by a spindle motor. The slider 1 is
attached via a flexure to a load beam 2 supported by an actuator
arm 3. The slider 1 `flies` over the surface of the magnetic disk
10 at a high velocity reading data from and writing data to
concentric data tracks on the disk 10. The head/slider 1 is
positioned radially by an actuator 20, comprising an actuator coil
13 housed in an actuator frame 8.
[0003] In typical hard disk drives, electrical control signals are
communicated to the voice coil motor (actuator 20) by a head stack
assembly (HSA) flexible circuit 9. Typically, the HSA flexible
circuit 9 also communicates read/write data to the head(s) 1. The
flexible circuit 9 attaches to the actuator coil 13 via an actuator
board 7, containing a preamplifier chip 11 (mounted to the actuator
arm 3).
[0004] FIG. 2 provides a more detailed view of a hard disk drive
arm as is typical in the art. The actuator board 7 is usually
electrically coupled to the actuator coil 13 by one or more
actuator coil leads 18 attached typically by soldering or
ultrasonic bonding 20. It can be difficult to get a good solder
bond on non-rigid surfaces, such as on a polymer substrate, and
thus, solderless bonding techniques, such as in U.S. Pat. No.
4,970,365 and U.S. Pat. No. 5,298,715, have been suggested.
Further, removing adhesive or solder flux contamination presents a
problem (as described below) necessitating solderless bonding
techniques.
[0005] FIG. 3 illustrates a typical technique of solderless lead
bonding as provided by U.S. Pat. No. 4,970,365. A
laser/ultrasonic-assisted thermal compression technique is utilized
where laser (or ultrasonic) energy is used for attaching fine pitch
components to non-rigid substrates. Typically, the laser/ultrasonic
energy is used to pulse heat a fine-point capillary tip 22, placed
in forced intimate contact with a lead 16 and pad 14.
[0006] There are disadvantages associated with the above method of
bonding. For example, such methods provide poor bonding strength,
and thus, the reliability and durability of such bonds are lacking.
A bond defect can cause degraded performance or failure of the head
stack assembly. The nature of this type of bonding prevents rework
or salvage of the bonded components. Further,
laser/ultrasonic-assisted thermal compression techniques require
costly, high precision equipment. Also, cleaning flux, which is
necessary for effective soldering is difficult and costly. Further,
solder, which consists primarily of tin, can cause component
contamination. During soldering, such as soldering coil leads 18 to
the connection pads on an actuator board 7 (See FIG. 2), tin may
splash out causing damage to surrounding electrical components
and/or disk media.
[0007] It is therefore desirable to have a system and method for
improving the electrical connection of the hard drive actuator coil
that avoids the above-mentioned problems, as well as having
additional benefits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 provides an illustration of a typical hard disk
drive.
[0009] FIG. 2 provides a more detailed view of a hard disk drive
arm as is typical in the art.
[0010] FIG. 3 illustrates a typical technique of solderless lead
bonding as known in the art.
[0011] FIG. 4 illustrates the attachment of a hard disk drive
actuator board to an actuator coil according to an embodiment of
the present invention.
[0012] FIG. 5 provides a different perspective of the attachment of
a hard drive actuator board to an actuator coil according to an
embodiment of the present invention.
[0013] FIG. 6 illustrates the attachment of a hard disk drive
actuator board to an actuator coil flexible cable according to an
embodiment of the present invention.
[0014] FIG. 7 provides a more detailed illustration of the
attachment of a hard disk drive actuator board to an actuator coil
flexible cable according to an embodiment of the present
invention.
[0015] FIG. 8 provides another illustration of the attachment of an
actuator coil to a flexible cable according to principles of the
present invention.
[0016] FIG. 9 provides another illustration of the attachment of an
actuator coil to an actuator board via a flexible cable according
to an embodiment of the present invention.
[0017] FIG. 10 provides a further illustration of actuator
coil/actuator board attachment via a flexible cable according to an
embodiment of the present invention.
[0018] FIG. 11 provides a photograph of actuator coil/actuator
board attachment via a flexible cable according to an embodiment of
the present invention.
DETAILED DESCRIPTION
[0019] FIG. 4 illustrates the attachment of a hard disk drive
actuator board to an actuator coil according to an embodiment of
the present invention. In one embodiment, a flexible cable 19
(relay flexible cable) is utilized to attach the actuator board 7
to the actuator coil 13. In this embodiment, Anisotropic Conductive
Film (ACF) is used to couple the flexible cable 19 to the actuator
board 7, as explained further below.
[0020] FIG. 5 provides a different perspective of the attachment of
a hard drive actuator board to an actuator coil according to an
embodiment of the present invention. In one embodiment, the
flexible cable 19 (relay flexible cable) is attached to the
actuator coil 13 via actuator leads 18, bonded to the flexible
cable 19, such as by solder bump bonding 20. Further in an
embodiment, the coupling is encased in a polymer actuator frame.
(See FIGS. 10 and 11).
[0021] FIG. 6 illustrates the attachment of a hard disk drive
actuator board to an actuator coil flexible cable according to an
embodiment of the present invention. As stated above, in one
embodiment, ACF 17 is utilized to electrically bond the actuator
board 7 to the flexible cable 19. (See also FIG. 7).
[0022] FIG. 7 provides a more detailed illustration of the
attachment of a hard disk drive actuator board to an actuator coil
flexible cable according to an embodiment of the present invention.
In one embodiment, a layer of a bonding agent 17, such as ACF
(Anisotropic Conductive Film), is sandwiched between electrical
contact pads 21 of the actuator board 7 and electrical contact pads
22 of the flexible cable 19. ACF 17, such as 3M.TM. 7303 Z-Axis
Film, is a film of adhesive material containing conductive
particles 25, such as silver-coated glass spheres 0.035 millimeters
in diameter. In one embodiment of the present invention, a heated
bonding tip 26 is pressed to the flexible cable to compress the
bonding agent 17 (e.g., the ACF) between the actuator board 7 and
the flexible cable 19. In this embodiment, upon compression a
number of conductive particles 25 are wedged and embedded between
the pads 21 of the actuator board 7 and pads 22 of the flexible
cable 19, forming discrete electrical pathways between the pads 21,
22 facing one another. In this embodiment, the bonding tip 26 is
maintained applying pressure and heat to the bonding agent 17
(through the flexible cable 19) for a predetermined amount of time
(e.g., 20 to 30 seconds) and at a predetermined temperature (e.g.,
200.degree. Celcius) to cure the adhesive in the bonding agent 17
and to bond the conductive particles 25 to the pads 21, 22.
Further, because a bonding agent 17 such as ACF can be pre-tacked
into position before permanently bonding (because the bonding agent
is tacky), there is less likelihood of incorrect positioning.
[0023] FIG. 8 provides another illustration of the attachment of an
actuator coil to a flexible cable according to principles of the
present invention. In one embodiment, solder bump bonding 20 is
utilized to electrically couple one or more actuator leads 18 of
the actuator coil 13 to the flexible cable 19. After attachment,
the coupling is embedded in a polymer actuator frame 8, such as by
injection molding. (See FIGS. 9, 10 and 11).
[0024] FIG. 9 provides another illustration of the attachment of an
actuator coil to an actuator board via a flexible cable according
to an embodiment of the present invention. In one embodiment, a
portion of the actuator coil (not shown) and the actuator
coil/flexible cable 19 coupling is enclosed in a mold (not shown).
In this embodiment, the mold is then injected with a material such
as polymer to form an actuator frame 8. In this embodiment, the
mold is then removed, leaving the polymer frame 8, which protects
the electrical connections from outside contamination.
[0025] FIG. 10 provides a further illustration of actuator
coil/actuator board attachment via a flexible cable according to an
embodiment of the present invention. As explained above, in one
embodiment, a portion of the actuator coil 13 and the actuator
coil/flexible cable 19 coupling is enclosed in a polymer actuator
frame 8.
[0026] FIG. 11 provides a photograph of actuator coil/actuator
board attachment via a flexible cable according to an embodiment of
the present invention. As explained, in this embodiment, a portion
of the actuator coil 13 and the actuator coil/flexible cable 19
coupling is enclosed in a polymer actuator frame 8.
[0027] Although several embodiments are specifically illustrated
and described herein, it will be appreciated that modifications and
variations of the present invention are covered by the above
teachings and within the purview of the appended claims without
departing from the spirit and intended scope of the invention.
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