Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-05-02
2003-07-01
Vo, Peter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S603070, C029S603130, C029S603150, C216S022000, C360S125330
Reexamination Certificate
active
06584676
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to magnetic read/write heads for exchanging data with magnetic storage media. More particularly, the invention concerns a process for manufacturing a pole tip trimmed read/write head with increased resistance to wear and debris collection, sharp pole tip corners, and reduced tip recession by backfilling slider pockets and lapping slider surfaces to create a level air bearing surface with a more distinct write component. Another aspect of the invention is an apparatus embodying such a read/write head.
2. Description of the Related Art
In this modern information age, there is a tremendous volume of electronic data for people and computers to manage. The management requirements not only involve transmission, receipt and processing of this information, but storage of the data as well. And, with more data to store, computer users are demanding extremely high capacity digital data storage devices. People store digital data using magnetic disk drives, removable diskettes, magnetic tape, CD-ROMs, and many other forms.
One approach to increasing storage capacity is to increase the size of the storage device. Another, more challenging approach is to increase the density of the stored data. In this way, more information can be stored in the same size of storage device. Thus, engineers developing especially small systems such as laptop computers are motivated by two opposing forces: the need to make smaller and lighter storage devices on one hand, but the need to store more data on the other.
In the disk drive field, read/write head structure is a critical factor in the ability to build smaller drives. There are many known varieties of read/write head, many of which have been developed by International Business Machines Corp. (“IBM”), and described in issued patents assigned to IBM. One recent development is the Focused Ion Beam Machining (“FIBM”) technique, which is used to manufacture read/write heads with greater write density. Basically, the FIBM technique uses ion milling to reduce the size of certain head subcomponents, thereby increasing the storage density.
FIG. 1
depicts an exemplary slider
100
to help explain the FIBM technique more specifically. The slider
100
includes an air bearing surface (“ABS”)
102
which normally glides over a storage disk (not shown) separated by a thin cushion of air called an “air bearing” (not shown). In the illustrated example, the slider
100
moves in a direction
105
relative to the storage medium. The ABS
102
is raised with respect to a neighboring surface
104
that is recessed due to etching, ion milling, etc. As one example, the slider
100
may be composed of a mixture of aluminum oxide (Al
2
O
3
) and titanium carbide (TiC).
The slider
100
has a leading edge
106
and a trailing edge
108
. Near the trailing edge
108
lies a pole tip structure
110
, which lies flush with the ABS
102
and contains circuit components that actually perform the read and write operations. These circuit components are deposited onto the trailing edge
108
of the slider
100
, which may also be called the “deposit end.”
FIG. 2
shows the pole tip structure
110
in greater detail. The pole tip structure
110
performs reading and writing operations with various subcomponents, such as poles, shields, read elements, and the like. In this example, the pole tip structure
110
includes a shield
200
, a combined shield/pole
202
, and a pole
204
. Between the shield
200
and shield/pole
202
lies a read element (not shown), such as a magnetoresistive (“MR”) stripe in the case of a MR head. Read operations are performed cooperatively by the shield
200
, MR stripe, and shield/pole
202
. Write operations are performed by the shield/pole
202
and the pole
204
cooperatively.
The FIBM technique uses a focused ion beam to remove portions of the shield/pole
202
, portions of the pole
204
, and portions of the material intervening between the shield/pole
202
and pole
204
. This technique is also called “pole tip trimming.” This creates recessed areas
206
. Pole tip trimming effectively narrows the sections of the pole
204
and shield/pole
202
that face each other. The resultant protrusions
250
-
251
of the shield/pole
202
and the pole
204
enable the slider
100
to write to a smaller area, therefore boosting storage density. The opposing protrusions
250
-
251
are joined by the connecting region of the ABS
102
form a bridge
208
. To further illustrate the pole tip structure
110
,
FIG. 3
illustrates the structure
110
in perspective view.
Although the FIBM technique constitutes a significant advance and may even enjoy significant commercial and/or scientific recognition, IBM continually seeks to improve the performance and efficiency of disk drive systems, including the read/write head subcomponents.
SUMMARY OF THE INVENTION
Broadly, the present invention concerns a process for manufacturing a pole tip trimmed read/write head with increased resistance to wear and debris collection by backfilling slider pockets and lapping slider surfaces to create a level air bearing surface with a more distinct write component.
Initially, the read/write head includes a substrate with an air bearing surface that includes a pole tip structure. The pole tip structure has a shield, a shield/pole substantially parallel to the shield, and an outer pole substantially parallel to the shield/pole. A gap region separates the pole and the shield/pole. First, pole tip trimming is performed to the read/write head to remove matter from the shield/pole, the pole, and the gap region. This defines a bridge composed of protrusions of the shield/pole and the pole joined by a connecting region of the intervening gap region. The bridge separates recessed areas, each formed by removing a contiguous mass from the shield/pole, the gap region, and the pole.
Next, thin film deposition is performed to apply a coating material over the pole tip structure, filling the recessed areas. The coated surface is then trimmed sufficiently to remove all coating material overlying the shield/pole and pole. Trimming may be performed by lapping or polishing, for example. Trimming is continued to additionally remove a top layer of the protrusions of the pole and shield/pole, and to remove any rounded edges created by pole tip trimming, resulting in a more distinct write head.
Accordingly, in one embodiment the invention may be implemented to provide a method to manufacture a pole tip trimmed read/write head. In another embodiment, the invention may be implemented to provide an apparatus, such as a pole tip trimmed read/write head, or a disk drive system utilizing such a head.
The invention affords its users with a number of distinct advantages. First, the invention reduces the possibility of collecting debris in recessed areas of a pole tip patterned slider. In turn, this helps reduce friction between the slider and disk, avoiding head/disk wear. Avoiding head/disk wear helps prevent data loss resulting from head/disk damage. Additionally, eliminating a collection site for debris imparts additional benefits to the head, such as resistance to corrosive attack of the pole-tips due to entrainment of corrosive debris, and resistance to head crashes caused by accumulated debris dropping onto the disk.
A further advantage of the invention is also provided by the encapsulation of the recessed trenches caused by pole tip trimming techniques such as FIBM. Namely, the encapsulation of the trenches helps avoid any corrosion hazards posed by corrosive materials such as gallium, which may be implanted in the pole tip structure during pole tip trimming. By encapsulating the trimmed trenches, these corrosive materials are sequestered under an overlayer that reduces the likelihood of their release in a reactive form, especially in proximity to the trimmed pole tips themselves.
The invention also helps reduce the recession of the pole and shield/pole regions from the ABS, which helps maintain the strength of both write and
Chang Thomas Young
Chang Yu-En Percy
Parker Michael A.
Dan Hubert & Assoc.
International Business Machines - Corporation
Trinh Minh
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