Patent Application
20070035878
1. Field of the Invention
This invention relates generally to the field of perpendicular magnetic recording heads and more particularly, to a notched trailing shield thereof and a method for manufacturing the same to avoid magnetic field leakage thereby improving overwrite and adjacent track interference problems.
2. Description of the Prior Art
As the recording density of magnetic hard drives (or disk drives) increases, a physical limitation is experienced using longitudinal recording systems partly due to thermal relaxation known as super-paramagnetism. That is the density requirements for meeting today's storage needs are simply not attainable with longitudinal recording systems. To provide further insight into this problem, it is anticipated that longitudinal recording systems will lose popularity as storage capacities in excess of about 150 Gigabytes-per-square-inches become a requirement. These and other factors have lead to the development and expected launch of perpendicular recording heads or write heads. Perpendicular recording is promising in pushing the recording density beyond the limit of longitudinal recording.
Accordingly, perpendicular recording potentially can support much higher linear density than longitudinal recording due to lower demagnetizing fields in recorded bits, which diminish when linear density increases.
A magnetic recording head for perpendicular writing generally includes two portions, a writer for writing or programming magnetically-encoded information on a magnetic media or disk and a reader portion for reading or retrieving the stored information from the media.
The writer of the magnetic recording head for perpendicular recording typically includes a main pole and a return pole, magnetically separated from each other, at an air bearing surface (ABS) of the writer by a nonmagnetic gap layer, and which are magnetically connected to each other at a back gap closure (yoke). This structure is referred to as a single-pole write head because while a main pole and return pole are referred thereto, the return pole is not physically a pole, rather, it serves to close the loop with the main pole and the soft under layer for magnetic flux circuit.
Positioned at least partially between the main and return poles are one or more layers of conductive coils encapsulated by insulation layers. The ABS is the surface of the magnetic head immediately adjacent to the recording medium.
To write data to the magnetic medium, an electrical current is caused to flow through the conductive coil, thereby inducing a magnetic field through the write head yoke, fringing across the write head gap at the media. By reversing the polarity of the current through the coil, the polarity of the data written to the magnetic media is also reversed.
The main and return poles are generally made of a soft magnetic material. Both of them generate magnetic field in the media during recording when the write current is applied to the coil.
In perpendicular recording heads, writing and erasing of information is performed by a single-pole write head. The main pole is composed of high moment magnetic materials, the most common example being cobalt-iron (CoFe) alloys or laminate layers.
With the advent of perpendicular recording heads, density has been greatly increased, as discussed hereinabove, which has lead to a greater need for accurate recording of data onto the desired track. That is, writing to adjacent tracks is. highly undesirable because it causes corruption of data on adjacent tracks. Additionally, overwriting reduction due to magnetic field leakage is currently a problem associated with perpendicular heads that is highly undesirable. In this connection, magnetic field leakage disrupts concentration of the magnetic field in a particular area, which results in less overwriting and reduced performance. Therefore, it is desirable to improve the concentration of magnetic field in a particular area thereby improving overwriting.
Perpendicular write heads generally have a trailing shield, side shields, a top pole and a bottom return pole. The main pole is generally shaped in a manner causing a tip or an extension thereof that is narrower than the remaining portion thereof to form a top pole. The side shields act to shield the top pole so as to reduce adverse affects on adjacent tracks during the writing of magnetic transitions (data) at a location on a given track. One way to address the problems associated with overwriting and adjacent track interference is by notching the trailing shield, however, due to small critical dimension and alignment issues, it is difficult to form notched trailing shield. That is, in perpendicular write heads, controlling the critical gap thickness, i.e. the thickness between the top pole and the trailing shield, is problematic, furthermore, the alignment of the trailing shield with the main pole is problematic. Yet another problem is damage to top pole and top pole corner rounding caused from chemical mechanical planarization (CMP) process, such as described in further detail below.
In the recording head, the main pole and trailing shield are separated by the gap layer, and require improvement for controlling the deposition of the gap layer so as to have well-controlled critical gap thickness between the top pole and the trailing shield.
The main pole is generally beveled (or trapezoidal) in shape in an effort to reduce adjacent track writing. Controlling the pole width so as to better line up with the track to be written thereto needs improvement also, as does controlling the angle of the bevel of the bevel-shaped design of the top pole.
It is vital for the corners of the bevel of the main pole to be straight rather than rounded, which is often experienced during manufacturing of the main pole and trailing shield. Such corner rounding generally results in the magnetic field that is induced onto the disc to be curved rather than straight. This effect adversely impacts system performance by degrading accurate recording of data onto the disc, as well as, unnecessarily higher power consumption.
Thus, in light of the foregoing, there is a need for a perpendicular recording head having a main pole and notched trailing shield manufactured to pattern the notched trailing shield and to eliminate top pole corner rounding while having well-controlled critical gap thickness between the main pole and the trailing shield and wherein the notched trailing shield is self-aligned with the main pole.
Briefly, one embodiment of the present invention includes a perpendicular write head and a method of manufacturing the same, the perpendicular write head for writing data onto tracks, the perpendicular write head having a main pole having notched trailing shield being self-aligned on the main pole for improved overwriting and adjacent track interference.
Referring now to
During operation of the disk drive 100, rotation of the disk 116 generates air movement which is encountered by the slider 110. This air movement acts to keep the slider 110 afloat a small distance above the surface of the disk 116, allowing the slider 110 to fly above the surface of the disk 116. The VCM 102 is selectively operated to move the actuator arm 104 around the axis 120, thereby moving the suspension 106 and positioning the—transducer (not shown), which includes a main pole (not shown), by the slider 110 over the tracks 118 of the disk 116. It is imperative to position the—transducer properly to read and write data from and to the concentric tracks 118.
Next, an ion milling process is performed to create the structure 218 of
Next, in
Next, a reactive ion milling process 232 is performed, as shown in
Next, in
The track width is basically defined at 237 of
The presence of the notch helps to align the main pole and the trailing shield. After deposition of the gap/seed layer 240, in
Although the present invention has been described in terms of specific embodiments, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. It is therefore intended that the following claims be interpreted as covering all such alterations and modification as fall within the true spirit and scope of the invention.
