Metal fusion bonding – Process – With shaping
Reexamination Certificate
1998-08-26
2002-05-07
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
With shaping
C228S110100, C029S603030, C029S603060, C360S100100
Reexamination Certificate
active
06382499
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a process for appropriately attaching a slider to a suspension assembly in a magnetic storage system and more specifically to a method for executing an ultrasonic bonding to appropriately attach a slider to a thin multi-piece integrated suspension assembly used in a small-sized magnetic disk storage system and a method for handling the suspension assembly for that purpose.
A magnetic disk drive is an information storage unit using at least one rotatable disk having concentric data tracks including information, a head (or “transducer”) for reading data from or write data in these numerous tracks and a head positioning actuator connected to this head for moving the head to a desired data track and retaining the head on the center of the track during the reading or writing operation. The transducer is mounted on a air bearing slider (hereinafter, simply abbreviated to “slider”) and supported near the data surface of the disk by an air cushion generated by the rotating disk. By using the suspension, the slider is mounted on the support arm of the head positioning actuator.
FIG. 1
exemplifies a schematic simplified block diagram of a magnetic disk storage system
40
including a flexure to which a slider is bonded. The magnetic disk storage system
40
comprises at least one rotatable magnetic disk
42
supported on the spindle
44
and rotated by a disk drive motor
46
and at least one slider
48
positioned near the magnetic recording medium on the disk surface
43
. Data are stored on the magnetic recording medium on each disk
42
in a ring pattern format of concentric data tracks (not shown). Each slider
48
includes one or more magnetic resistor (MR) sensors and write transducers.
A slider
48
is mounted on an integrated suspension
50
and further the integrated suspension
50
is connected to actuator means
54
by using an actuator arm
52
. As a disk
42
rotates, the slider
48
is so controlled by actuator means
54
as to move across means disk surface
43
and the slider
48
accesses or reads a different portion of the disk surface
43
in which desired data are recorded. The integrated suspension
50
gives such a slight spring force as to bias the slider
48
relative to the disk surface
43
, thereby controlling a slight vertical elasticity of the slider
48
relative to the rotating disk surface
43
. Actuator means
54
as seen in
FIG. 1
is, for example, a voice coil motor (VCM). Various components of the magnetic disk storage system
40
are operatively controlled in accordance with a control signal generated by the control unit
56
. For example, the operating control of various components includes positioning control of the actuator means
54
, motor control of the drive motor
46
and read/write control of data.
The integrated suspension
50
does not only act to dimensionally stabilize the distance between the slider
48
and the actuator arm
52
during the relative movement on the surface of a rotating magnetic disk, but also controls such motions as “pitch and roll motions” (hereinafter, referred to as “gimbaled motions or gimbal motion”), among them especially a slight “vertical motion” of the slider
48
. The “vertical motion” in the present specification is to be defined as a motion along a nearly vertical distance between the magnetic disk surface and the air bearing surface of a slider mounted on the suspension when a rotating magnetic disk surface is assumed and the “vertical direction” is to be defined as a bidirection toward the magnetic disk surface and toward the air bearing surface of a slider mounted on the suspension. It may be considered to be a direction perpendicular to the air bearing surface.
On pursuing a higher record density, a greater number of data tracks must be packed on the disk surface and the necessity of formatting the disk surface into a narrower data track or into a narrower space between data tracks is urged. To cope with such a challenge, a slider is first downsized. And, it is falling under a category of pico slider. Letting an oblong of 4 mm×2 mm be the standard slider, the pico slider means a slider corresponding to about 30% of its size (about 1.3 mm×0.5 mm). With decreasing area of the air bearing surface of a slider, a force received by the slider from a rotating magnetic disk is necessarily reduced.
Corresponding to such downsizing of a slider, a delicacy will be required concerning the suspension structure, in particular, demand for performance specification concerning a flexure becomes even stricter. Even under a strict tolerance in the alignment of a slider/track, in order that dense stacked data/tracks are accessible and a slider can accurately and repeatedly be positioned to the disk surface, the flexure of an integrated suspension should be strongly built so as to retain the flexibility and reliability even if light/thin.
Since the constitution of an integrated suspension
50
has been improved day by day and various types are present, various names are given even to components of a suspension and are mixed with each other. Accordingly, it has become difficult to precisely call individual pieces with universal names and distinguish them. As one example of constitution among downsized suspensions, however, one comprising a “load beam” mounted on the actuator arm of a head positioning actuator and a “flexure” supported on the load beam for supporting a slider can be mentioned. The “load beam” generally provides an elastic spring action for biasing a slider to the disk surface, whereas the “flexure” generally acts to provide flexibility to a slider so that the slider gets on an air cushion close to the rotating disk.
U.S. patent application Ser. No. 08/644878, entitled “A Multi-Piece Integrated Suspension Assembly for a Magnetic Storage System”, filed 1996-5-10 and assigned to the same applicant as that of the present application discloses a new integrated suspension structure having such a constitution. Here, a thin flexible member and conductive leads are integrally formed. Through the presentation of the suspension structure of this U.S. patent application Ser. No. 08/644878 that has not yet publicly known at the application time of the present invention, embodiments of the present invention will be described.
Meanwhile, for comparison, a conventional suspension structure that has so far been fabricated and a bonding method of bonding pads of a slider and wires which is suitable thereto will be described over
FIGS. 2
to
7
. The suspension structure here is one example of joined structure of the suspension
50
and the actuator arm
52
of FIG.
1
. The wires here and the conductive leads described in the present invention are different in name but identical in the function of making an electrical connection. However, the wires to which a reference is made here as background art differ from conductive leads, are coated with a tube
26
(cf.
FIG. 3
) for insulation as a separate single piece and are not integrated with a flexible member unlike the present invention.
FIG. 2
is a perspective view showing a conventional head suspension assembly. This head suspension assembly includes a slider
48
and a suspension assembly
12
and a wire assembly
16
and a construction that the wires are retained by caulking at the site
14
is adopted.
FIG. 3
is a plan view showing a wired suspension assembly
20
of background art with a tab structure
22
extending from the suspension assembly
12
provided in consideration of convenience for ultrasonic bonding. This is disclosed in JA 995078 of patent application No. 7-264413 assigned to the same applicant as that of the present application. In this aspect, wires are already stretched and mounted on a suspension assembly. In
FIG. 3
, however, a slider
48
is not yet mounted unlike FIG.
2
and no slider cannot be seen in FIG.
3
. Accordingly, the process of mounting/bonding of a slider will be described.
As shown in
FIG. 4
, when wires
18
are bridged over a tab
Kurosu Naoki
Satoh Takuya
Tsuchiya Tatsumi
Yoshida Tatsushi
Dunn Tom
Edmondson L.
Millett Douglas R.
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