JP3807713B2 - Manufacturing method of magnetic head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a method of manufacturing a magnetic head used for writing magnetic recording on a hard disk and a magnetic head using the same, and further relates to a hard disk device using the magnetic head.
[0002]
[Prior art]
As is well known to those skilled in the art, a hard disk device has a magnetic disk disk as a magnetic recording medium, a magnetic head for writing and reading a magnetic recording signal on the disk, and a magnetic head on the disk. A servo mechanism for accessing the designated position, an electric circuit for signal processing, and the like are included as main elements. One of the most important items of the performance of the hard disk drive is the surface recording density. In order to improve the surface recording density, it is necessary to increase the linear recording density and the track density.
[0003]
Among these, in order to improve the track density, it is indispensable to narrow the track width in the track portion of the magnetic head for writing, and it is necessary to reduce the leakage magnetic flux during writing. The technical problems required for such a magnetic head for writing are described in detail in, for example, Nikkei Electronics, and an example of the structure of the track portion is described in US Pat. No. 5,285,340.
[0004]
[Problems to be solved by the invention]
However, these conventional techniques are not established as a specific manufacturing process for the entire head including a magnetic circuit and a coil for driving the magnetic circuit, and are not optimized as a structure of the magnetic head. Therefore, there has been a problem that is not sufficient for actually manufacturing a magnetic head and providing a high-performance hard disk drive at low cost.
[0005]
That is, it is not sufficient to manufacture only the track tip for manufacturing the write magnetic head, and rationally design the structure of the write head including the coil portion and the upper magnetic core portion and a series of manufacturing processes. At the same time, it is necessary to overcome the difficulty of adapting the material optimized to satisfy the characteristics required for the magnetic head to the manufacturing process.
[0006]
A reasonable manufacturing method for manufacturing a write head having a narrow track width, which has overcome such difficulties, has not been provided so far.
[0007]
The first object of the present invention made in view of such problems is to provide a magnetic head for writing including a track portion, a coil portion, an upper magnetic core portion, etc., which are rationally configured to simultaneously meet the various problems described above. It is to provide a structure of a write head for manufacturing and a series of manufacturing processes.
[0008]
A second object of the present invention is to provide an optimal combination of magnetic head materials suitable for the manufacturing process.
[0009]
A third object of the present invention is to provide a high performance magnetic disk apparatus using the magnetic head.
[0010]
[Means for Solving the Problems]
As means for solving the above-mentioned problems, the present invention relates to an upper magnetic core and a lower magnetic core of a magnetic circuit of a write head, and a laminated structure comprising a first magnetic body, a non-magnetic body and a second magnetic body. In addition to the feature of connecting the track portion and the back gap portion with a material, the magnetic head is characterized in that the end portion of the upper magnetic core is located inside the air bearing surface. The means of the present invention will be described in detail below with reference to FIG.
[0011]
FIG. 1A shows the lower magnetic core 1 of the magnetic head for writing.
[0012]
On the lower magnetic core 1, a laminated structure material composed of a first magnetic body 2, a nonmagnetic body 3 and a second magnetic body 4 is formed by plating at two locations of a track portion A and a back gap portion B. This is defined as (b).
[0013]
Next, the coil lower insulating layer 5 is formed in a predetermined portion excluding the track portion A and the back gap portion B, and the coil lower insulating layer 5 and the laminated structure material are flattened. (C)
Next, a driving coil 6 is formed on the insulating material 5. (D)
Next, the coil insulating material 7 is formed and the coil 6 is completely covered. (E)
Next, the upper magnetic core 8 is formed so that the exposed laminated structural material is connected to the track part A and the back gap part B. At this time, the upper magnetic core 8 is formed so that the end thereof is retracted from the air bearing surface and the angle of the end is in the range of 45 to 90 degrees, preferably in the range of 60 to 85 degrees. (F)
Next, an insulating material 9 is formed so as to cover the entire write head including the upper magnetic core 8 part, the coil 6 part, the track part A, and the back gap part B. (G)
Finally, the head is completed by cutting and polishing so that the air bearing surface C is exposed. Needless to say, in order to ensure the performance as a magnetic head, steps such as formation of a protective film and rail processing of the air bearing surface are necessary after the above-described steps.
[0014]
In the present invention, a magnetic head can be manufactured by adding a step of removing the nonmagnetic material 3 and the second magnetic material 4 in the back gap portion B, which is shown in FIG.
[0015]
By performing the above-described series of steps (a) to (g) in order, the upper magnetic core and the lower magnetic core of the magnetic circuit of the write head according to the present invention are replaced with the first magnetic body and the nonmagnetic body. Thus, a magnetic head can be manufactured in which the track portion and the back gap portion are connected to each other by a laminated structure material composed of the first and second magnetic bodies.
[0016]
Although the present invention can be manufactured using a series of steps as described above, there is a close relationship between each step, the relationship before and after the step, and the materials used in the step.
[0017]
Normally, in a composite head in which a read MR head (or GMR head) and a write head are separated, the lower magnetic core 1 also serves as the upper shield of the MR head. However, it goes without saying that the present invention can also be used for manufacturing a so-called inductive thin film head in which the reading head and the writing head are the same.
[0018]
The laminated structure of the present invention can be continuously formed by a plating method called a so-called frame plating method. That is, when the laminated structure is plated on the track portion A and the back gap portion B, a resist frame is formed in a shape surrounding the track portion A and the back gap portion B, and then the track portion, the back gap portion and the others. After this, plating is performed on the substrate, and after that, the unnecessary portion of the plating is removed by etching while protecting the track portion A and the back gap portion B with a cap resist, and finally the frame resist is removed. Can be used. The laminated structure material of the present invention can be formed by sequentially performing plating using the frame resist on the first magnetic body 2, the nonmagnetic body 3, and the second magnetic body 4.
[0019]
In the present invention, it is important to simultaneously form the track portion A and the back gap portion B and to adjust the area ratio of the laminated structure material of the track portion A and the back gap portion B to 0.1 to 0.00001.
[0020]
Usually, a magnetic gap is not formed in the back gap portion B, but a general structure of a conventional magnetic head. This is because the magnetic gap formed in the back gap portion B may adversely affect the write characteristics of the head. However, in order to form the track portion A with the laminated structure material using the above method and not to form the magnetic gap in the back gap portion B, it is necessary to add a manufacturing process.
[0021]
It is possible to realize the present invention even if such an additional manufacturing process is adopted, and a structure in which the non-magnetic body 3 in the back gap portion is removed and the magnetic circuit is directly connected with the soft magnetic body as follows. It is also possible to do.
[0022]
That is, the nonmagnetic material 3 and the second magnetic material 4 are removed by dry etching such as ion milling or reactive ion etching using at least a photoresist pattern having an opening in the back gap as a mask, or by wet etching. It is. By subsequently forming the upper magnetic core, it is possible to directly connect the magnetic circuit with a soft magnetic material without forming a magnetic gap in the back gap portion B.
[0023]
However, since the process is complicated in the above method, in order to avoid such a problem, the track portion A and the back gap portion B are simultaneously formed of a laminated structure material, and the track portion A and the back gap portion B are stacked. The area ratio of the structure body is preferably adjusted to be 0.1 to 0.00001. By simultaneously forming the track part A and the back gap part B, the manufacturing process can be greatly simplified, and the area ratio of the laminated structure of the track part A and the back gap part B becomes 0.1 to 0.00001. By adjusting in this way, it is possible to prevent the magnetic gap of the back gap portion B from adversely affecting the write characteristics of the head.
[0024]
When the gap thickness is g, the vacuum permeability is μ 0, the area of the track part A (after the head is completed) is S 1, and the area of the back gap part B is S 2, the combined gap of the track part and the back gap part The approximate value R of the magnetic resistance can be expressed by the following equation.
[0025]
[Expression 1]
R = g / μ0 (1 / S1 + 1 / S2)
From this relationship, when the area ratio S1 / S2 of the laminated structure of the track part A and the back gap part B is 0.1 to 0.00001, the influence of the magnetic gap of the back gap part B on the magnetoresistance of the gap can be ignored. As a result, it is possible to prevent the head writing characteristics from being adversely affected.
[0026]
In the present invention, the track width formed by the laminated structure material is 0.3 to 1.5 μm, thereby enabling extremely high density magnetic recording. The lower limit of the track width is determined from a practical viewpoint capable of forming a photoresist frame, and the upper limit is determined from a range in which a desirable recording density can be obtained.
[0027]
In the present invention, the thickness of the first magnetic body 2 is 0.2 to 1.0 μm, the thickness of the nonmagnetic body 3 is 0.1 to 0.5 μm, and the thickness of the second magnetic body 4 is 0.2 to 1.0 μm. It is desirable to be μm. The lower limit of the thickness is determined from the viewpoint that the writing magnetic flux from the track tip is in a practical range, and the upper limit is determined from the range in which the photoresist frame can be formed.
[0028]
The nonmagnetic material 3 of the present invention is characterized by being Pd, Rh, Pt, Au, Cu or a nonmagnetic alloy containing them. Such a metal is selected because it can be easily plated and has excellent adhesion to the first magnetic body 2 and the second magnetic body 4. A platinum group such as Pd, Rh, Pt, or the like similar to this, which generates little sagging due to polishing, is particularly preferred.
[0029]
Furthermore, a soft magnetic alloy having a saturation magnetic flux density of 1.0 to 2.2 T is used for the first magnetic body 2 and the second magnetic body 4 of the present invention. In order to obtain a sufficiently strong head magnetic field, the saturation magnetic flux density is preferably larger. In order to obtain a magnetic body having such a saturation magnetic flux density, a soft magnetic alloy containing at least one component selected from Ni, Fe and Co or a soft magnetic alloy containing these elements may be used. Plating can be used to obtain a magnetic alloy.
[0030]
On the other hand, the lower magnetic core 1 and the upper magnetic core 8 of the present invention are also soft magnetic alloys having a saturation magnetic flux density of 1.0 to 2.2 T, similar to the first magnetic body 2 and the second magnetic body 4. Is used.
[0031]
It is recommended that the lower magnetic core 1 and the upper magnetic core 8 have a thickness of 0.5 to 5.0 μm. The upper and lower limits of the thickness are determined from the fact that the writing characteristics or the shielding effect as a composite head can be sufficiently secured.
[0032]
In the coil lower insulating layer 5 of the present invention, an organic insulating film obtained by baking a positive photoresist or an oxide insulating material such as alumina or silica is preferably used alone or in combination, but other insulating materials are not used. is not.
[0033]
The planarization of the present invention means that after depositing the coil lower insulating layer 5 on the entire surface of the substrate on which the laminated structure is formed in the track part A and the back gap part B, a technique such as CMP (Chemical Mechanical Polishing) is used. It is preferable that the upper surface of the coil lower insulating layer 5 and the upper surface of the laminated structure be polished so as to be in the same plane. Such polishing is a technique well known to those skilled in the art.
[0034]
The coil 6 according to the present invention is formed by forming a planarized laminated structure and a coil plating base film (not shown) on the surface of the coil lower insulating layer 5 by sputtering or the like and forming a coil plating frame resist. A method known to those skilled in the art can be used in which the coil is formed of a low-resistance metal such as Cu, and the exposed base film for coil plating is removed by milling or the like after removing the frame resist.
[0035]
As the coil insulating material 7 of the present invention, a material obtained by baking a positive photoresist can be used, but an oxide such as alumina or silica is not necessarily used as an insulating material.
[0036]
In the formation of the upper magnetic core 8 of the present invention, a photoresist frame is formed after sputtering (not shown) of the underlayer for plating, and plating in a magnetic field is performed in order to ensure the magnetic anisotropy of the upper magnetic core 9. A method well known to those skilled in the art can be used, such as forming a cap resist on the required portion later, removing the unnecessary portion of the plating by etching, removing the frame resist, and removing the plating base film by milling. .
[0037]
The upper magnetic core 8 of the present invention is characterized in that the end of the upper magnetic core is located inside the air bearing surface. The distance L between the upper magnetic core end and the air bearing surface as shown in FIG. 2 is defined to be 0.1 to 3 μm. The retraction of the upper magnetic core end from the air bearing surface is dramatic in order to prevent the leakage magnetic field from the upper magnetic core end from being exposed to the air bearing surface from affecting the magnetic recording. effective.
[0038]
Furthermore, it is also a feature of the present invention that the elevation angle θ of the end of the upper magnetic core of the present invention is 45 degrees or more and 90 degrees or less. The reason for providing such an angle is that it has a great effect in preventing the insulating material 9 to be formed later from falling off.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention are described below. FIG. 3 is a plan structural view of the magnetic head corresponding to the cross-sectional structural view of FIG. 1 described above. In order to make the explanation easy to understand, in FIG. 3, several layers constituting the magnetic head are overwritten.
[0040]
FIG. 4 is a cross-sectional view of the air bearing surface C shown in FIG.
[0041]
The lower magnetic core 1 of the present invention is arranged as shown in FIG. The lower magnetic core 1 serves as an upper shield of the MR element 12 disposed below the lower magnetic core 1.
[0042]
Specifically, after the MR element 12 is formed on the lower shield 11 formed on the wafer 10 made of a material such as alumina titanium carbide, the upper shield (lower magnetic core 1) of the MR element 12 is formed. The lower magnetic core 1 is used.
[0043]
For example, a Ni—Fe soft magnetic alloy having a saturation magnetic flux density of about 1.0 T can be used for the lower magnetic core 1 of the present invention. Such a soft magnetic alloy is a permalloy alloy having an Ni composition of about 80% and is well known to those skilled in the art for its properties and preparation methods.
[0044]
For example, the thickness of the lower magnetic core 1 is set to 3.0 μm. A photoresist frame for forming the track portion A and the back gap portion B is formed on the lower magnetic core 1, and three layers of the first magnetic body 2, the nonmagnetic body 3, and the second magnetic body 4 are plated. Are sequentially applied to form the laminated structure of the present invention. Thereafter, the plating other than the track portion A and the back gap portion B is removed by etching. As an example, a Ni—Fe soft magnetic alloy having a Ni composition of about 46%, which is a high Bs soft magnetic material, can be used for the first magnetic body 2 and the second magnetic body 4. Nonmagnetic Pd plating can be used as the nonmagnetic material 3.
[0045]
The photoresist height is set to 2.5 μm, the track width is set to 0.9 μm, and the track part area / back gap part area ratio is set to 0.0003. The thickness of the first magnetic body 2 and the second magnetic body 4 is 1.0 μm, and the thickness of the non-magnetic body is 0.2 μm.
[0046]
In the present invention, a photoresist frame for forming a fine track portion A plating can be formed on a flat surface on the lower magnetic core 1, so that the photoresist can be formed with extremely high accuracy. This allows fine and precise control of the track width.
[0047]
Next, alumina as a coil lower insulating layer 5 is deposited on the entire surface to a thickness of 3.0 μm, and is polished by CMP so that the upper surface of the coil lower insulating layer 5 and the upper surface of the laminated structure are flush with each other. Specifically, polishing the alumina deposited with a slurry containing alumina fine abrasive grains and finishing the polishing when the upper surface of the laminated structure is exposed to efficiently create a flattened polished surface. Can do.
[0048]
In the present invention, the driving coil 6 is then formed on the alumina of the coil lower insulating layer 5. The height and width of the coil 6 are each estimated to be 3.0 μm. The number of turns of the coil should also be determined from the head design, and eight turns are selected as an example. Furthermore, the coil is not limited to one layer, and it is possible to prevent the increase in the head area due to the increase in the number of turns by forming two coils. The coil 6 is formed by forming a coil plating base film such as Cu / Cr on the entire surface by sputtering or the like, forming a coil plating frame resist, forming the coil 6 by plating, and removing the frame resist. The exposed base film for coil plating may be removed by milling or the like.
[0049]
In the present invention, the coil insulating material 7 obtained by baking a positive photoresist is used.
[0050]
In the present invention, the upper magnetic core 8 is formed so as to be connected by the track part A and the back gap part B. For example, a Ni—Fe soft magnetic alloy having a saturation magnetic flux density of 1.0 T can be used for the upper magnetic core 8.
[0051]
The upper magnetic core 8 of the present invention is formed by forming a photoresist frame after sputtering (not shown) of the plating base film, and performing plating in a magnetic field to ensure the magnetic anisotropy of the upper magnetic core 8. A method well known to those skilled in the art can be used, such as forming a cap resist on the required portion later, removing the unnecessary portion of the plating by etching, removing the frame resist, and removing the plating base film by milling. . As an example, a magnetic field of 0.1 T may be applied to ensure good magnetic anisotropy. The present invention can be realized by using a mask in which the end of the upper magnetic core 8 recedes from the air bearing surface in forming such a photoresist frame. As an example, the value of the backward distance W is recommended to be 0.5 μm. Furthermore, an elevation angle can be provided by using a negative resist for the frame resist. As an example, an elevation value of 80 degrees is recommended.
[0052]
In the present invention, the entire write head including the upper magnetic core 8 and the coil 6 is covered with an alumina insulating material 9 to complete the write head lamination process.
[0053]
A block including a plurality of heads is cut out from a wafer on which a large number of such heads are formed, and the air bearing surface is polished, the air bearing surface is processed with a rail, and the head protective film is formed, and is divided into a single head to complete a magnetic head.
[0054]
FIG. 5 shows an example of a method for incorporating the magnetic head 20 manufactured as described above into the magnetic disk device 24. The magnetic head 20 of the present invention is configured to be mounted on a suspension 21 in advance and driven by a servo actuator 22. A plurality of magnetic disks 23 serving as recording media are rotated by the same cylinder. In order to use both sides of the disk as a recording medium, it is well known to those skilled in the art to normally mount two magnetic heads on one magnetic disk. In this way, the magnetic disk device 24 is completed.
[0055]
In the magnetic disk device 24 of the present invention, the magnetic head 20 of the present invention is used, and a track recording density of 22 kTPI (track per inch) is obtained by using a magnetic disk 23 having a coercive force medium of 2000 Oersted and using a rotational speed of 4000 rpm. ), A remarkably excellent recording performance of a recording density of 5 Gbit / square inch can be achieved at a linear recording density of 230 kBPI (bit per inch).
[0056]
Further, by further narrowing the track width to 0.5 μm, setting the track area / back gap area ratio to 0.0001, and further setting the thickness of the non-magnetic material to 0.1 μm, further recording can be performed. The density can be improved. In such a case, a track recording density of 34 kTPI (track per inch) is possible by using a magnetic disk having a coercive force of 3000 oersted, and a linear recording density of 300 kBPI (bit per inch) and a recording density of 10 Gbit / square inch. The above remarkably excellent recording performance can also be achieved.
[0057]
A magnetic head that can be used for such high-performance magnetic recording can be provided by a simple manufacturing process because of the excellent head structure of the present invention and a manufacturing method for realizing the head structure.
[0058]
【The invention's effect】
The present invention simultaneously provides a method of manufacturing a high-performance magnetic head by a remarkably simple process and a novel magnetic head structure. When the magnetic head of the present invention is used, a remarkably high-performance magnetic disk drive can be made inexpensive. There are immeasurable economic effects because they can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a manufacturing process of a magnetic head of the present invention with reference to cross-sectional views.
FIG. 2 is a cross-sectional view illustrating a part of the structure of the magnetic head of the present invention with reference to a cross-sectional view.
FIG. 3 is a diagram illustrating the structure of a magnetic head of the present invention using a plan view.
FIG. 4 is a cross-sectional view illustrating the structure of an air bearing surface of a magnetic head according to the present invention using a cross-sectional view.
FIG. 5 is a perspective view showing the appearance of a magnetic disk device using the magnetic head of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Lower magnetic core, 2 ... 1st magnetic body, 3 ... Nonmagnetic body, 4 ... 2nd magnetic body, 5 ... Coil lower insulating layer, 6 ... Coil, 7 ... Coil insulating material, 8 ... Upper magnetic core DESCRIPTION OF SYMBOLS 9 ... Insulating material, 10 ... Wafer, 11 ... Bottom shield, 12 ... MR element, 20 ... Magnetic head, 21 ... Suspension, 22 ... Servo actuator, 23 ... Magnetic disk, 24 ... Magnetic disk apparatus.

Claims (1)

In the method of manufacturing a magnetic head,
Forming the lower magnetic core,
On the lower magnetic core, a laminated body having a first magnetic body, a second magnetic body, and a non-magnetic body positioned between the first magnetic body and the second magnetic body is formed,
The upper magnetic core is on the far side from the depth position in the range of 0.1 μm or more and 3.0 μm or less from the air bearing surface, and the end of the upper magnetic core in the film thickness range on the air bearing surface side is the air bearing surface side From the top surface of the laminate when viewed in the depth direction, and having an end surface having an angle in the range of 80 ° to 85 °,
The method of manufacturing a magnetic head, wherein the end surface of the upper magnetic core is formed by plating using a negative resist.

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