Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
1998-11-02
2002-05-07
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
Reexamination Certificate
active
06385012
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thin-film magnetic head having a thin-film magnetic head element and a plurality of electrodes for electrically connecting the element to an external device and a method of manufacturing the thin-film magnetic head, and to a thin-film magnetic head material used for manufacturing the thin-film magnetic head and a method of manufacturing the material.
2. Description of the Related Art
Performance improvements in thin-film magnetic heads have been sought with an increase in surface recording density of a hard disk drive. A composite thin-film magnetic head has been widely used which is made of a layered structure including a recording head (which may be called recording element in the following description) having an induction magnetic transducer for writing and a reproducing head having a magnetoresistive (MR) element for reading. MR elements include an anisotropic magnetoresistive (AMR) element that utilizes the AMR effect and a giant magnetoresistive (GMR) element that utilizes the GMR effect. A reproducing head using an AMR element is called AMR head or simply MR head. A reproducing head using a GMR element is called GMR head. An AMR head is used as a reproducing head whose surface recording density is more than 1 gigabit per square inch. A GMR head is used as a reproducing head whose surface recording density is more than 3 gigabits per square inch.
In general, an AMR film is made of a magnetic substance that exhibits the MR effect and has a single-layer structure. In contrast, many of GMR films have a multilayer structure consisting of a plurality of films. There are several types of mechanisms of producing the GMR effect. The layer structure of a GMR film depends on the mechanism. GMR films include a superlattice GMR film, a spin valve film and a granular film. The spin valve film is most efficient since the film has a relatively simple structure, exhibits a great change in resistance in a low magnetic field, and suitable for mass production.
Besides selection of a material as described above, the pattern width such as the MR height, in particular, is one of the factors that determine the performance of a reproducing head. The MR height is the length (height) between the end of an MR element closer to the air bearing surface (medium facing surface) and the other end. The MR height is basically controlled by an amount of lapping when the air bearing surface is processed.
Performance improvements in a recording head have been expected, too, with performance improvements in a reproducing head. It is required to increase the track density of a magnetic recording medium in order to increase the recording density among the performances of a recording head. In order to achieve this, a recording head of a narrow track structure has been desired to be manufactured by processing the magnetic pole into the submicron order through the use of semiconductor process techniques. The magnetic pole made of a magnetic material having high saturation flux density has been desired in order to achieve the narrow-track recording head.
Another factor determining the recording head performance is the throat height. The throat height is the length (height) of the portion (called pole portion in the present invention) between the air bearing surface and the edge of the insulating layer electrically isolating the thin-film coil. A reduction in throat height is desired in order to improve the recording head performance. The throat height is controlled as well by an amount of lapping when the air bearing surface is processed.
As thus described, it is important to fabricate a recording head and a reproducing head appropriately balanced so as to improve performances of a thin-film magnetic head.
The manufacturing process of a thin-film magnetic head includes a wafer process for forming thin-film patterns on a wafer as a substrate and a lapping process for adjusting the throat height and the MR height by lapping. The wafer process includes a number of mask steps, film forming steps by plating and sputtering, etching steps by sputtering, dry etching, wet etching and so on, and lapping steps by chemical mechanical polishing (CMP) and the like. The performance and characteristics of the thin-film magnetic head may be modified by changing the track width of the reproducing element and the track width of the recording element and so on. Therefore, thin-film magnetic heads that meet a variety of needs of customers may be manufactured by determining the track width of the reproducing element and that of the recording element and so on, using masks that satisfy required specifications.
The manufacturing process of a thin-film magnetic head includes a number of steps and it takes an extremely long period of time to manufacture one product. Therefore, in order to manufacture the magnetic head having the performance and characteristics that meet the needs of the customer, it is required to carefully work out a detailed production plan so that the performance and characteristics of the magnetic head may be changed by photomask selection.
However, the needs of the customers are not limited to those relating to the performance and characteristics of the thin-film magnetic head that are determined in the wafer process but embrace the needs relating to a slider for retaining the magnetic head element and flying over the surface of a hard disk platter. The needs of the customers for a slider may be, for example, whether to choose a side element type slider or a center element type slider. The side element type slider is a slider wherein a thin-film magnetic head element is formed near an end of the slider in the direction orthogonal to the direction of air flow. The center element type slider is a slider wherein a thin-film magnetic head element is formed in the center of the slider in the direction orthogonal to the direction of air flow. The side element type slider and the center element type slider are typical sliders. In these days sliders are tend to be largely categorized into the above two types for satisfying the demand for the flying characteristics over the surface of the hard disk platter.
Reference is now made to
FIG. 35
to
FIG. 38
for describing the side element type slider and the center element type slider.
FIG. 35
is a schematic front view of a surface of the side element type slider in which a thin-film magnetic head element is formed.
FIG. 36
is a schematic bottom view of the air bearing surface of the side element type slider. In
FIG. 36
the arrow indicated with numeral
120
shows the direction of air flow. ‘LE’ indicates the air inflow end. ‘TR’ indicates the air outflow end. In the side element type slider, as shown in FIG.
35
and
FIG. 36
, a thin-film magnetic head element
111
is formed near an end of the slider in the direction orthogonal to the direction of air flow, in the vicinity of an end face (end face of air outflow end TR in this example)
110
orthogonal to the direction of air flow. On the end face
110
, four pad-shaped electrodes
112
are provided for electrically connecting the magnetic head element
111
to an external device. The four electrodes
112
are connected to the magnetic head element
111
through four conductors
113
. A rail
115
is formed in the air bearing surface of the slider.
FIG. 37
is a schematic front view of a surface of the center element type slider in which a thin-film magnetic head element is formed.
FIG. 38
is a schematic bottom view of the air bearing surface of the center element type slider. Numeral
120
, ‘LE’ and ‘TR’ of
FIG. 38
are similar to those of FIG.
36
. In the center element type slider, as shown in FIG.
37
and
FIG. 38
, the thin-film magnetic head element
111
is formed in the middle of the slider in the direction orthogonal to the direction of air flow, in the vicinity of an end face (end face of air outflow end TR in this example)
110
orthogonal to the direction of air flow. On the end face
110
, four pad-shaped electrodes
Oliff & Berridg,e PLC
TDK Corporation
Tupper Robert S.
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