The present invention relates to a method of manufacturing a magnetic head and a magnetic head, more precisely relates to a method or manufacturing a write-head of a magnetic head and a magnetic head having a unique structure.
A conventional magnetic head of a magnetic disk unit is shown in
The write-head 10 of the magnetic head is formed by the steps of: forming the lower magnetic pole 12 and the coils 14 on a surface of a wafer (a workpiece) by sputtering or plating; forming a nonmagnetic layer, which acts as the write-gap 11, by sputtering; forming a resist layer 16, which raises a rear part of the end section of the upper magnetic pole 13; and forming the upper magnetic pole 13 by plating. The resist layer 16 is optically exposed and developed, so that the end section of the upper magnetic pole 13 has a prescribed apex angle θ.
After forming the upper magnetic pole 13, both sides of the magnetic poles 12 and 13 are etched by ion milling so as to make a pole end section of the write-head narrow (see Japanese Patent Gazette No. 2000-11320).
In
When the write-head is ion-milled from the upper magnetic pole 13 to the lower magnetic pole 12 so as to make the pole end section narrow, the surface of the wafer other than a specific area, which will be the pole end section, is coated with resist. However, when the resist is patterned, the resist slightly extends beyond the pole end section. Further, in recent magnetic heads, core widths are narrower and narrower, so it takes a long time to ion-mill the magnetic poles. Therefore, when the magnetic poles 12 and 13 are etched by ion milling, the etching badly influences the coils 14, which are located under the upper magnetic pole 13.
Namely, in the conventional magnetic head, a nonmagnetic layer, which acts as the write-gap 11, and the resist layer 16, is formed on the coils 14. When the pole end section is ion-milled as indicated by arrows shown in
If the coils 14 are etched when the pole end section of the write-head is carved by etching (ion milling), the coils 14 cannot be insulated from the upper magnetic pole 13, and resistances and inductances of the coils 14 are varied.
The present invention was conceived to solve the above described problems.
An object of the present invention is to provide a method of manufacturing a reliable magnetic head, in which an upper magnetic coil can be securely insulated from a coil and variation of coil resistance can be restrained, and said magnetic head.
To achieve the object, the present invention has following constitutions.
Namely, the method of manufacturing a magnetic head having a write-head comprises the steps of: forming a recording coil of the write-head formed in a workpiece; coating a surface of a coil forming area of the write-head, in which the recording coil is formed, other than a front end part of a lower magnetic pole of the write-head, with a protection layer, which prevents the recording coil from being etched by ion milling; and etching a pole end section of the write-head, by ion milling, so as to have a prescribed width.
In the method, the coating step may comprise the steps of: coating an area, other than the area to be coated with the protection layer, with resist; forming the protection layer on a surface of the workpiece, which has been coated with the resist; and removing a part of the protection layer by lift-off, so that the protection layer is left on the surface of the coil forming area.
The method may further comprise the step of flattening a surface of the workpiece, and the flattening step is performed between the forming step and the coating step. By flattening the surface of the workpiece, the highly accurate upper magnetic pole can be formed.
The method may further comprise the steps of forming a write-gap with resist. In this case, a part of the resist forming the write-gap, which corresponds to a rear part of the pole end section, is raised, and this step is performed after the coating step.
In the method, the protection layer may be an alumina film. Since rate of etching alumina, by ion milling, is low, the coil can be effectively protected from the ion milling.
The magnetic head of the present invention comprises: a lower magnetic pole; an upper magnetic pole; a write-gap being formed between the lower magnetic pole and the upper magnetic pole; a recording coil being sandwiched between the lower magnetic pole and the upper magnetic pole; a protection layer coating a surface of a coil forming area, in which the recording coil is formed, other than a front end part of the lower magnetic pole; and a resist layer coating a surface of the protection layer. Note that, the protection layer prevents the coil from carving in the ion milling process, so it is made of a specific material whose ion milling rate is low.
In the magnetic head, the resist layer may make a rear part of a pole end section of the write-head has a prescribed apex angle.
In the magnetic head, the front end part and the recording coil may have polished faces, which are included in the same plane.
Further, the magnetic head may further comprise a magnetic layer being provided on a surface of the front end part, the magnetic layer having high saturation magnetic flux density. With this structure, the write-head is capable of performing high density recording.
In the magnetic head, the protection layer may be made of alumina.
By employing the method of the present invention, when the pole end section of the write-head is processed by ion milling, the recording coil, which is provided under the upper magnetic pole, can be protected by the protection layer. Therefore, short circuit between the coil and the upper magnetic pole and variation of resistance and inductance of the coil can be prevented, so that the highly reliable magnetic head can be produced. Further, the magnetic head of the present invention is not damaged in the ion milling process, so it can be provided as the highly reliable magnetic head.
According to the present invention will now be described by way of examples and with reference to the accompanying drawings, in which:
Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
An embodiment of the method of manufacturing a unique write-head is shown in
In
In
In
In
In
In
In
In
In
After forming the upper magnetic pole 13, the end sections of the magnetic poles 12 and 13 are ion-milled as shown in
In the method of the present embodiment, the end section of the upper magnetic pole 13 is etched, and the sides of the lower magnetic pole 12 are etched as if they are carved. At that time, the coil 14b, which is located close to the lower magnetic pole 12, is coated with the alumina protection layer 40, so that the protection layer 40 prevents the coil 14b from being etched. Since rate of etching alumina, by ion milling, is low, the alumina protection layer 40 is capable of effectively protecting the coil 14b from etching or ion milling.
In the present embodiment, the surface of the coil 14b is coated with the alumina protection layer 40, so that the surface of the coil 14b, which may be badly influenced by etching or ion milling, can be protected from being carved by ion milling. Other materials, e.g., oxides, nitrides, whose etching rates are low, may be used as the materials of the protection layer 40.
By coating the surface of the coil 14b with the protection layer 40, the problems of the conventional magnetic head, such as short circuit between the coil 14b and the upper magnetic pole 13, which is caused by etching the coil 14b when the pole end part of the write-head is ion-milled, and variation of resistance and inductance of the coil 14b, can be solved.
The inventor measured coil resistance, coil inductance, etc. of the magnetic head manufactured by the method of the present embodiment and the conventional magnetic head. The results are shown as TABLE 1.
According to TABLE 1, the method of the present embodiment, in which the surface of the coil 14b was coated with the protection layer 40, more effectively restrained variations of resistance and inductance of the coil 14b than the conventional method. Further, the method of the present embodiment securely prevented short circuit between the coil 14a and the upper magnetic pole 13.
Note that, in the above described embodiment, the magnetic head includes two layers of the coils, but number of layers of the coils is not limited. The magnetic head may include one coil, or three or more number of layered coils. The magnetic head of the above described embodiment is a horizontal recording head, but the present invention can be applied to a vertical recording head. In case that a coil for recording data is etched when a pole end section or a trailing shield of a vertical recording head is ion-milled, the present invention may be applied.
The invention may be embodied in other specific forms without departing from the spirit of essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Number | Date | Country | Kind |
---|---|---|---|
2006-062176 | Mar 2006 | JP | national |