JPH0963018A - Production of thin-film magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce a thin-film magnetic head capable of improving reproduction characteristics and embodying a high recording density by decreasing undershoot. SOLUTION: A photoresist is applied on a metallic ground surface film 8 and a resist frame 9 is patterned to the shape corresponding to the shape of an upper magnetic film in such a manner that the film thickness (t) of this film has a relation t<=T with respect to the target thickness T of an upper pole part on at least the surface facing a magnetic recording medium. An upper magnetic film 10 is electroplated with these patterns as a mask to a prescribed film thickness, by which the upper pole part 11 is so formed as to have a straight edge flat on the magnetic gap side and upward projecting edge 14 on the side opposite to a magnetic gap.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a pair of upper and lower pole portions facing each other across a magnetic gap on a substrate, and is used, for example, in a magnetic disk recording device, particularly in a storage device such as a computer word processor. The present invention relates to a method of manufacturing a thin film magnetic head suitable for high recording density.

[0002]

2. Description of the Related Art Conventionally, a thin film magnetic head has been used to increase the recording density as the capacity of a magnetic disk recording apparatus increases. The thin-film magnetic head has a small thickness of the magnetic film forming the pole portion at the head tip, that is, the pole length, in order to achieve high recording density. Is known to cause undershoot. The undershoot waveform affects adjacent isolated playback waveforms, causing deterioration of the playback signals and occurrence of read data errors.In addition, the peak shift becomes large, and the read error margin or phase margin is limited. There is a problem that it becomes a cause of hindering the increase in recording density.

In order to suppress undershoot, for example, in the thin film magnetic head disclosed in Japanese Patent Laid-Open No. 62-287411, the edge forming the gap between the magnetic poles and the edge on the opposite side are made non-parallel. JP-A-4-1320
The thin film magnetic heads described in Japanese Patent No. 9 and No. 13210,
By curving the gap or the outer edge of the pole portion so as to change the thickness of the pole portion, the edge of the pole portion moves in the width direction according to the running of the magnetic recording medium, and the undershoot is substantially eliminated. It is small enough to be ignored. A similar configuration is disclosed in JP-A-4-35670.
No. 4 publication, a protrusion is provided on the outer edge of the pole portion so as to have a width in the front-rear direction with respect to the traveling direction of the magnetic recording medium so that the entire edge does not pass through the magnetization reversal portion at once. Then, the undershoot in the reproduced signal is flattened. Also, Japanese Patent Application Laid-Open No. 5-26
In Japanese Patent No. 6429, the tip of the pole portion is partially removed on the side opposite to the gap film from the recording medium facing surface side by ion milling or the like, so that the magnetic characteristic of the pole portion along the traveling direction of the magnetic recording medium is obtained. Gradually decreases
A thin film magnetic head has been proposed in which the undershoot is small enough to be ignored.

[0004]

However, the above-described conventional thin-film magnetic head requires a special technique and an additional manufacturing process to form the pole portion in a desired shape, and thus the workability and the dimensional accuracy are improved. However, there is a problem in that there is a possibility that the yield may be reduced and the cost may be increased. JP 62-
In the thin-film magnetic head disclosed in Japanese Patent No. 287411, the manufacturing process is extremely complicated and the number of steps is increased because the left and right asymmetrical upper and lower magnetic poles are formed. In the case of JP-A-4-13209 and 13210, it is actually very difficult to stably control the composition of the plating bath so as to bend the cross-sectional shape in the plating process of forming the pole portion. Is. Further, in the thin film magnetic head described in JP-A-4-356704, the photoresist formed on the surface of the substrate is patterned and reflowed, the exposed surface is removed by ion etching to form a recess, and the lower magnetic layer is formed on the surface of the substrate. Since the film is electroplated to form the protrusion on the tip of the lower pole, there is a problem that the manufacturing process is complicated and the number of steps is increased. Further, the same publication does not disclose a manufacturing process for forming a protrusion on the upper pole portion.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a thin film magnetic head capable of reducing undershoot in a reproduction signal with a special technique. Another object of the present invention is to provide a method which can be manufactured relatively easily by utilizing the conventional technique without requiring the addition of complicated steps.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and its contents will be described below with reference to the embodiments shown in the drawings. The method of manufacturing a thin film magnetic head of the present invention comprises a step of laminating a lower magnetic film having a lower pole portion on a substrate, a magnetic gap film, an insulating layer and a conductor coil layer, and a step of applying a photoresist and forming an upper magnetic film. The photoresist comprises a step of patterning into a corresponding shape and a step of forming an upper magnetic film having an upper pole portion facing the lower pole portion through the magnetic gap film by electroplating using this as a mask. Has a film thickness t of at least on the surface facing the magnetic recording medium.
The target thickness T of the upper pole portion has a relationship of t ≦ T.

According to the method of the present invention, the upper pole portion is electroplated, for example, by electroplating a permalloy film using a photoresist having a film thickness t less than the target thickness T of the upper pole portion as a mask. The edge on the side of the magnetic gap has a flat linear shape, and the edge on the side opposite to the magnetic gap, that is, the outer edge can be formed in a shape that is convexly curved upward. Since the outer edge of the upper pole portion has a width in the front-back direction with respect to the traveling direction of the magnetic recording medium, signal processing is performed while the magnetization reversal portion of the magnetic recording medium is dispersed, resulting in undershoot occurring in the isolated reproduction signal. The peak can be suppressed and flattened, so that the reproduction characteristic can be improved and the read error can be prevented. Thus, by utilizing the conventional manufacturing process as it is, and optimizing the photoresist and the plating conditions for forming the upper magnetic film, the thin film magnetic head capable of suppressing the undershoot can be easily manufactured.

The magnetic recording width of the thin film magnetic head is determined by the width of the upper pole portion on the magnetic gap side. If the photoresist film thickness t is set to 2000 angstroms or more, the upper pole portion on the magnetic gap side is formed. This is convenient because the width of can be controlled to be constant.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. 1A, B
In a non-magnetic substrate 1 made of an Al ₂ O ₃ —TiC ceramic material, a lower magnetic film 3 is formed on an insulating film 2 such as alumina (Al ₂ O ₃ ) on the non-magnetic substrate 1 as in the conventional thin film magnetic head. However, for example, Co-Zr-Nb system, Fe-Al-Si
A magnetic gap that is patterned into a predetermined size and shape by sputtering or electroplating a soft magnetic material such as a system or permalloy alloy, and on which an oxide insulating material such as alumina or silicon dioxide (SiO ₂ ) is formed. The film 4, the first to third insulating layers 5 such as novolac resin, and the first and second conductor coils 6 made of Cu are laminated by using a photolithography technique. The tip portion of the lower magnetic film 3 forms the lower pole portion 7. Then, for example, permalloy alloy (NiFe, NiFe / Ti) is formed on the entire substrate.
Etc.), Cu / Cr, Cu simple substance is sputtered, and the thin metal base film 8 is covered. The thickness of the metal base film 8 is preferably 2000 angstroms or less.

According to the present invention, a photoresist is applied to the surface of the substrate shown in FIG. 1 and exposed to light using a photomask to pattern it into a desired size and shape of the upper magnetic film, as shown in FIG. 2A. Then, the resist frame 9 is formed. At the position where the film thickness t of the resist frame is at least the surface facing the recording medium shown in cross section in FIG. 2A, the target film thickness T is the thickness required for the upper pole portion of the upper magnetic film during writing. In this case, the relationship of t ≦ T is formed.

In another embodiment, the photoresist is first applied relatively thickly, the resist frame 9 is formed, and then another photomask is used to form a portion for defining the upper pole portion of the resist frame. Re-exposure. The exposure range may be the entire resist frame portion defining the upper pole portion or only the portion near the position corresponding to the recording medium facing surface of the upper pole portion. By appropriately adjusting this exposure amount, the upper pole portion demarcating portion of the resist frame 9 is partially exposed and removed from the surface in the film thickness direction, and the height thereof is t ≦ T described above.
Can be adjusted to obtain the relationship.

Next, using the resist frame 9 as a mask, a soft magnetic material such as a permalloy alloy, for example, a NiFe film is deposited by electroplating to deposit the upper magnetic film 10.
As shown in FIG. 2B, the upper pole portion 11 is formed so that the required thickness, that is, the target film thickness T can be obtained. This electroplating is carried out using known methods and conditions such as the method of manufacturing a permalloy alloy thin film described in JP-A-57-9636. By providing the relationship of t ≦ T between the height t of the resist frame 9 and the target film thickness T of the upper pole portion, the NiFe film is deposited so as to bulge above the height of the resist frame 9. , Upper pole part 1
The upper surface of No. 1 has a shape protruding from the resist frame 9 in a round shape. Therefore, when the resist frame 9 and unnecessary portions of the magnetic film 12 and the metal base film 8 are removed by wet etching or the like, as shown in FIG. 2C, the lower pole portion 7 is formed.
Thus, the upper pole portion 11 that faces the magnetic gap film 4 is obtained.

Here, the film thickness t of the resist frame 9 is 2
Set it to 000 Å or more. This is because, in the case of the thin film magnetic head of the present embodiment, the magnetic recording width is restricted by the width W of the upper pole portion 11 in contact with the magnetic gap, and in order to control the magnetic recording width constant,
This is because it is necessary to provide a portion having a width W on the magnetic gap side with a predetermined thickness or more. Therefore, the thin film magnetic head of the present invention can obtain a highly accurate magnetic recording width depending on the width of the resist frame 9.

Further, a protective film 13 made of alumina, silicon dioxide or the like is further coated thereon by sputtering or the like to form terminals and the like necessary for external connection, and after cutting the wafer,
The thin film magnetic head of the present invention as shown in FIGS. 3A and 3B is completed by performing polishing processing so that a desired magnetic pole thickness can be obtained by pole height polishing.

The thin film magnetic head of the present invention comprises an upper pole portion 1
As shown in FIG. 3B, the outer edge 14 of No. 1 is curved upward from both left and right ends toward the center at least on the recording medium facing surface, so that the magnetization reversal portion of the recording medium is dispersed during reproduction. It is possible to reduce the undershoot generated on the trailing edge side of the reproduced waveform after the signal processing. Moreover, since the upper pole portion 11 has the target film thickness T in the central portion thereof, it is possible to secure sufficient writing ability.

FIG. 4 shows another embodiment of the photoresist for forming the upper pole portion according to the present invention. In this embodiment, when patterning the photoresist 15 applied on the substrate, only the portion 16 where the upper magnetic film is formed is exposed and removed, and it is not necessary to surround the resist frame 9 as in the above-described embodiments. The magnetic film does not adhere. By exposing only the necessary portion of the metal base film 8 to be plated in this way and performing electroplating, the potential concentration on the plated portion effectively acts, so that the upper surface of the upper pole portion is curved more roundly. It can be formed into a convex shape.

FIG. 5 shows another embodiment of the upper pole portion according to the present invention. For example, the target film thickness T of the upper pole part
Is considerably larger than the film thickness t of the resist frame 9,
The NiFe film spreads over the resist frame 9 and spreads over it, and the upper pole portion 17 is formed in a mushroom-shaped cross section. Also in the case of this embodiment, since the outer edge 18 of the upper pole portion 17 is curved upward from both right and left ends toward the center at least on the recording medium facing surface, the magnetization reversal of the recording medium is reproduced at the time of reproduction. Signal processing is performed while the parts are dispersed, and undershoot can be reduced. Further, similarly to the above-described embodiment, since the upper pole portion 17 has the width W and the film thickness t on the magnetic cap side by the resist frame 9, the magnetic recording width of the thin film magnetic head can be controlled to be constant. it can.

Although the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that the present invention can be implemented by making various changes and modifications to the above embodiments. For example, in the embodiment of FIG. 5, by patterning the resist frame as in the embodiment of FIG. 4, the outer edge of the upper pole portion 17 can be curved more roundly, whereby Ni protruding beyond the resist frame can be formed.
It is also possible to reduce the Fe film.

[0019]

Since the present invention is configured as described above, it has the following effects. Further, according to the method of manufacturing the thin film magnetic head of the present invention, the upper pole portion of the upper magnetic film can be formed by the conventional photolithography technique without newly using special techniques and equipment or adding many steps. Also, since it is possible to relatively easily form the desired shape and size for suppressing the undershoot by using the plating technique, the yield is improved and the manufacturing cost is reduced. Therefore, it is possible to inexpensively provide a high-performance thin-film magnetic head with improved information reproduction characteristics.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a substrate coated with a metal underlayer film for an upper magnetic film, and FIG. 1B is a sectional view taken along line BB corresponding to the surface facing a recording medium.

2A to 2C are diagrams showing a process of forming an upper magnetic film according to the method of manufacturing a thin-film magnetic head according to the present invention, in order of process steps.

3A is a cross-sectional view of a thin film magnetic head according to the method of the present invention, and FIG. 3B is an enlarged view of the same as seen from the magnetic recording medium side.

4 is a cross-sectional view similar to FIG. 2B showing another embodiment of photoresist patterned on a substrate.

FIG. 5 is a sectional view similar to FIG. 2C showing another embodiment of the thin film magnetic head according to the method of the present invention.

[Explanation of symbols]

 1 Substrate 2 Insulating Film 3 Lower Magnetic Film 4 Magnetic Gap Film 5 Insulating Layer 6 Conductor Coil 7 Lower Pole 8 Metallic Underlayer 9 Resist Frame 10 Upper Magnetic Film 11 Upper Pole 12 Magnetic Film 13 Protective Film 14 Outer Edge 15 Photoresist 16 part 17 upper pole part 18 outer edge

Claims (2)

[Claims] 1. A process of laminating a lower magnetic film having a lower pole portion on a substrate, a magnetic gap film, an insulating layer and a conductor coil layer, and applying a photoresist and patterning into a shape corresponding to the upper magnetic film. And a step of forming an upper magnetic film having an upper pole portion opposed to the lower pole portion via the magnetic gap film by electroplating using this as a mask, and the film thickness t of the photoresist is A method of manufacturing a thin film magnetic head, characterized in that at least a surface facing a magnetic recording medium has a relationship of t≤T with a target thickness T of the upper pole portion. 2. The film thickness t of the photoresist is 2000.
3. The thickness is angstrom or more.
The manufacturing method of the thin film magnetic head according to the above.