JPH06195635A - Production of thin film magnetic head - Google Patents

Abstract

PURPOSE:To extremely enhance yield and to reduce the number of processes. CONSTITUTION:Lower magnetic layers 15 for plural thin film magnetic heads are laminated on a wafer 10, an upper magnetic layer 30 is laminated on the lower magnetic layers 15 with at least a gap layer 23 in-between and the wafer 10 is cut to obtain thin film magnetic heads. At this time, protrusions 14 are formed at prescribed positions on the wafer 10 before the lower magnetic layers 15 are laminated and then the lower magnetic layers 15 are laminated so that edges of the lower magnetic layers 15 each confronting a magnetic medium are superposed on the protrusions 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film magnetic head for recording and / or reproducing on a magnetic medium such as a magnetic disk.

[0002]

2. Description of the Related Art In recent years, the density of magnetic recording devices has been increasing, and as a thin film magnetic head used in such magnetic recording devices, it has good magnetic recording density characteristics with no distortion in the recording / reproducing waveform. Is required.

However, in a thin film magnetic head having a normal structure, undershoot occurs before and after the main pulse of the isolated reproduction waveform, and the reproduction waveform is distorted. This undershoot is noise called a negative edge based on the finite pole length effect, and various configurations are known for suppressing the generation of this negative edge noise and reducing its influence.

For example, Japanese Patent Publication No. 53-29090 and Japanese Unexamined Patent Publication No. 62-287411 disclose a thin film magnetic in which the gap side edge and the opposite side edge of the end face of the magnetic pole facing the magnetic recording medium are non-parallel. The head is listed.

The present applicant has already proposed another method for apparently eliminating the occurrence of negative edge noise. FIG. 7 is a diagram schematically showing a part of the configuration of a thin film magnetic head of this type from the bottom side facing the magnetic medium, and FIG. 8 is a sectional view taken along line VIII-VIII thereof.

In these figures, 70 is a ceramic structure such as Al ₂ O ₃ -TiC that constitutes a slider, 71
Is a base film of Al ₂ O ₃ or the like formed thereon. A lower magnetic layer 72 made of permalloy or the like is formed on the base film 71, a gap layer 73 is provided thereon, and a coil conductor 75 is further sandwiched by an insulating layer 74, and permalloy or the like is provided thereon. The upper magnetic layer 76 is formed.
A protective film 77 is formed on the upper magnetic layer 76.

Surfaces 78 of the lower magnetic layer 72 and the upper magnetic layer 76 facing the magnetic medium, that is, the air bearing surface (AB) of the magnetic head.
(S-plane) is partially dug down to form a continuous step in the track width direction, whereby the pole lengths PL1 and PL2 of the lower magnetic layer 72 and the upper magnetic layer 76 are formed.
Is set to be small. By reducing the pole lengths PL1 and PL2 in this way, the negative edge portion is moved to the high-level main pulse portion,
As a result, the negative edge is hidden by the main pulse and apparently disappears, so that the distortion of the reproduced waveform can be eliminated.

In order to form such steps in the lower magnetic layer 72 and the upper magnetic layer 76, a plurality of thin film magnetic heads are formed in a matrix on the wafer, and then the wafer is cut into rows of thin film magnetic heads. To do. As a result, for example, as shown in FIG. 9, a bar 91 in which a plurality of thin film magnetic heads 90 are arranged in a line is obtained. ABS of bar 91 in this state
Photolithography and ion milling are performed from the surface 91a side to remove the portions 79 and 80 in FIGS. 7 and 8 by etching.

[0009]

However, according to the conventional manufacturing method as described above, since the photolithography and the ion milling are performed after cutting into the bar 91, the alignment is extremely difficult due to the warp or the like generated in the bar 91. Becomes difficult. Therefore, considering the influence on the peak shift, the dimensional tolerance is required to be about ± 0.1 μm, but the patterning of the photolithography cannot be performed accurately and the yield is deteriorated. Further, performing the photolithography and the ion milling process after cutting into the bar 91 significantly increases the number of steps, and the manufacturing cost increases accordingly.

After each layer of the thin film magnetic head is formed, photolithography and ion milling are performed from the ABS surface side, and the ABS near the end of the lower magnetic layer 72 is formed.
A part of the resist is exposed on the surface side. The resist exposed on the surface shrinks due to environmental changes and causes cracks, resulting in very poor yield. Further, as is clear from FIG. 8, since a recess is formed on the ABS surface side, a crash is likely to occur in a CSS (contact start stop) test or the like, and dust or the like may adhere to cause an operation error. There is also.

Therefore, the present invention solves the above-mentioned problems of the prior art, and provides a method of manufacturing a thin film magnetic head in which the yield rate is very good and the number of steps can be reduced.

[0012]

According to the present invention, lower magnetic layers of a plurality of thin film magnetic heads are laminated on a wafer, and an upper magnetic layer is laminated on the laminated lower magnetic layers through at least a gap layer. Then, in the method of manufacturing a thin film magnetic head in which the wafer is cut to obtain individual thin film magnetic heads, a convex portion is formed at a predetermined position on the wafer before laminating the lower magnetic layer, and each thin film magnetic head is formed. There is provided a method of manufacturing a thin film magnetic head, in which a lower magnetic layer is laminated such that an end of the lower magnetic layer on the side facing a magnetic medium overlaps a convex portion.

It is preferable that the side surface of the convex portion is formed to be inclined.

After stacking the upper magnetic layer, it is also preferable to partially remove the upper part of the end of the upper magnetic layer of each thin film magnetic head on the side facing the magnetic medium, and then cut the wafer.

It is also preferable that the change in the pole length based on at least the shape of the above-mentioned convex portion is monitored to adjust the throat height.

[0016]

The following processing is performed before the wafer is cut into bars. Before laminating the lower magnetic layer, a convex portion is formed on the wafer. Next, the lower magnetic layer is laminated such that the end of the lower magnetic layer of each thin film magnetic head on the side facing the magnetic medium overlaps the convex portion. After forming a protective film on it,
The wafer is cut into bars.

[0017]

The present invention will be described in detail with reference to the following examples.

FIG. 2 is a sectional view showing a part of a thin film magnetic head manufactured as an embodiment of the present invention.

As shown in the figure, 20 is a ceramic structure such as Al ₂ O ₃ --TiC which constitutes a flying slider,
Reference numeral 21 is a base film made of an electrically insulating material such as Al ₂ O ₃ or SiO ₂ formed thereon. On the base film 21,
Permalloy (Ni-Fe alloy) lower magnetic layer 22 is formed such, the gap layer 23 by such as Al ₂ O ₃ thereon, further Al ₂ O ₃ or SiO ₂ or the like of the insulating layer 24
A coil conductor 25 made of Cu, Au, or the like is provided between the two, and an upper magnetic layer 26 made of permalloy or the like is formed thereon. A protective film 27 made of Al ₂ O ₃ or SiO ₂ is formed on the upper magnetic layer 26.

As is clear from the figure, in the thin film magnetic head of the present embodiment, the lower magnetic layer 22 has a non-linear cross section, and the upper magnetic layer 2 has an end portion on the ABS surface 28 side.
It has a curved shape that approaches the 6 side. Further, a part of the end portion on the ABS surface 28 side of the upper magnetic layer 26 is cut out so that the pole length thereof is set to be small. As a result, the negative edge portion is moved to the high-level main pulse portion, and as a result, the negative edge is hidden by the main pulse and apparently disappeared, so that distortion of the reproduced waveform can be eliminated. Furthermore, in the thin film magnetic head of the present embodiment, the ABS surface 28 has a flat shape without a recess.

FIG. 1 shows the lower magnetic layer 22 in this embodiment.
FIG. 6 is a process chart showing the manufacturing process of

First, an electrically insulating material such as Al ₂ O ₃ or SiO ₂ is sputtered on the entire surface of a wafer 10 made of a ceramic structure such as Al ₂ O ₃ —TiC to form a base film 11.
(21) is formed. Then, an addressing step of forming a marker for alignment on this wafer is carried out.

First, as shown in FIG. 1A, a Ti film 12 is formed on the entire surface of the base film 11. Next, a photoresist pattern is formed at the marker position and a predetermined position where the convex portion related to the present invention is to be formed (the end position on the ABS side of the lower magnetic layer where each thin film magnetic head is to be formed), and ion milling is performed. Then, the photoresist is removed by ashing to form the marker 13 and the convex portion 14 as shown in FIG. The step between the marker 13 and the convex portion 14 is formed so that PL1 + PL2 <2 μm.
In the present embodiment, the sidewalls 14a of the protrusions 14 are formed so as to be inclined so that the width of the protrusions 14 expands downward (for example, the angle θ of the surface of the sidewall 14a is inclined to about 30 °). ing.

Thereafter, as shown in FIG. 1C, a lower magnetic layer 15 (22) is laminated by plating permalloy (Ni--Fe alloy) or the like. In this case, the lower magnetic layer 15 is laminated so that the end portions thereof overlap the convex portions 14. Although only one lower magnetic layer 15 is shown in FIG. 1, a large number of lower magnetic layers 15 for the respective magnetic heads will be formed on the wafer 10.

In the example of FIG. 1, since the convex portion is formed at the same time as the marker in the addressing step, the number of steps does not increase because the convex portion is formed. However, it is obvious that the convex portion may be formed in a process different from the addressing process. In that case, it is not always necessary to form the titanium film. Further, the side wall of the convex portion is preferably inclined, but it may be substantially right angle in some cases.

Al ₂ O is formed on the lower magnetic layer 15 (22).
A gap layer 23 made of ₃ or the like is laminated, and C is formed on the gap layer 23 by being sandwiched by an insulating film 24 such as Al ₂ O ₃ or SiO _2.
A coil conductor 25 made of u, Au, or the like is provided. The upper magnetic layer 26 is laminated by plating permalloy (Ni-Fe alloy) or the like on it.

FIG. 3 is a process diagram showing a process of processing the upper magnetic layer 26 in this embodiment.

As shown in FIG. 3A, permalloy or the like is plated to form the upper magnetic layer 30 (26), and then the upper magnetic layer 30 (26) is formed, as shown in FIG.
As shown in FIG. 5, a photoresist pattern 31 having a window is formed only on a predetermined position (the end position on the ABS surface side of the upper magnetic layer to be formed in each thin film magnetic head) thereon. In this state, after performing ion milling, the resist is peeled off. As a result, as shown in FIG. 3C, the recess 32 is formed at the end of the upper magnetic layer 30 on the ABS side.

Then, Al ₂ is formed on the upper magnetic layer 30.
By forming the protective film 33 (27) of O ₃ or SiO ₂ or the like, a large number of laminated bodies for thin film magnetic heads as shown in FIG. 4 are formed in a matrix on the wafer 10.
Next, the wafer 10 is cut into each thin film magnetic head array. As a result, for example, as shown in FIG. 7, a bar in which a plurality of thin film magnetic heads are arranged in a line can be obtained.

ABS of the thin film magnetic head array in this bar state
By polishing the surface to adjust the throat height and then cutting it, individual thin film magnetic heads whose partial cross section is shown in FIG. 2 are obtained.

As described above, in the thin film magnetic head of this embodiment, the lower magnetic layer 22 has a curved shape so as to approach the upper magnetic layer 26 side in the vicinity of the end on the ABS 28 side. Further, a part of the end portion on the ABS surface 28 side of the upper magnetic layer 26 is cut out so that the pole length thereof is set to be small. Therefore, similarly to the conventional thin film magnetic head of FIG. 6, the negative edge portion is moved to the high-level main pulse portion, and as a result, the distortion of the reproduced waveform can be eliminated.

In the case of manufacturing such a thin film magnetic head, according to the present invention, the processing of the ends of the lower magnetic layer and the upper magnetic layer on the ABS side is all performed on the wafer. Therefore, a large amount of processing can be performed without significantly increasing the number of steps, and highly accurate processing can be easily performed, and the yield can be significantly improved.

Further, according to the present invention, since photolithography and ion milling are not performed from the ABS surface side after forming each layer of the thin film magnetic head, there is a disadvantage that a part of the resist is exposed on the ABS surface side. Does not happen. As a result, the occurrence of cracks hardly occurs, the yield is greatly improved, and the reliability is significantly improved. Furthermore, AB
Since the S surface has a flat shape with no recesses, CSS
(Contact start / stop) There is no risk of causing a crash in a test or the like, and there is no risk of dust or the like adhering to cause an operation error.

In addition to the advantages described above, according to the present invention,
The labor for polishing and adjusting the throat height by polishing the ABS surface of the thin film magnetic head array in the bar state becomes very simple. That is, unlike the conventional case, it is not necessary to follow the throat height while measuring the numerical value of the pole length by using the machining marker, and the adjustment can be made only by monitoring the abrupt change of the pole lengths PL1 and PL2. Become.

FIGS. 5 and 6 are process diagrams showing a part of the manufacturing process of the lower magnetic layer in another embodiment of the present invention and a sectional view of a part of the thin film magnetic head thereof.

As shown in FIG. 5, after the step of FIG. 1 (B), permalloy (Ni--Fe alloy) or the like is plated in two steps to stack layers 15a (22a) and 15b (22b). The lower magnetic layer is formed. By forming the lower magnetic layer in such a shape, the magnetic characteristics can be improved. The other constructions and effects of this embodiment are the same as those of the embodiment of FIG.

In the above-mentioned embodiment, the ABS surface side end portion is processed for both the lower magnetic layer and the upper magnetic layer, but the ABS surface side end portion is processed only for the lower magnetic layer. May be. This is because the influence of the negative edge based on the finite pole length effect is particularly large on the lower magnetic layer side.

[0038]

As described in detail above, according to the present invention, the convex portion is formed at a predetermined position on the wafer before the lower magnetic layer is laminated, and the magnetic medium of the lower magnetic layer of each thin film magnetic head is formed. The lower magnetic layer is laminated so that the end on the opposite surface side overlaps the convex portion, and then the wafer is cut to obtain individual thin film magnetic heads, so the yield rate is very good. The number of steps can be reduced and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a lower magnetic layer of a thin film magnetic head in the embodiment of FIG.

FIG. 2 is a sectional view showing a part of a thin film magnetic head manufactured as an embodiment of the present invention.

FIG. 3 is a manufacturing process diagram of an upper magnetic layer of the thin film magnetic head in the embodiment of FIG.

FIG. 4 is a manufacturing process diagram of the thin-film magnetic head in the embodiment of FIG.

FIG. 5 is a manufacturing process diagram of the lower magnetic layer of the thin-film magnetic head in the embodiment of FIG.

FIG. 6 is a sectional view showing a part of a thin film magnetic head manufactured as another embodiment of the present invention.

FIG. 7 is a sectional view showing a part of a conventional thin film magnetic head.

8 is a sectional view taken along line VIII-VIII of FIG.

FIG. 9 is a perspective view of a bar in which a plurality of thin film magnetic heads are arranged in a line.

[Explanation of symbols]

 10 Wafers 11, 21 Underlayer film 14 Convex portion 14a Side walls 15, 22 Lower magnetic layer 23 Gap layer 24 Insulating layer 25 Coil conductor 26, 30 Upper magnetic layer 27, 33 Protective film 28 ABS surface

Claims (4)

[Claims] 1. A lower magnetic layer of a plurality of thin film magnetic heads is laminated on a wafer, an upper magnetic layer is laminated on the laminated lower magnetic layer through at least a gap layer, and then the wafer is cut into individual pieces. A method of manufacturing a thin film magnetic head for obtaining a thin film magnetic head, comprising forming a convex portion at a predetermined position on the wafer before laminating the lower magnetic layer, A method of manufacturing a thin film magnetic head, characterized in that the lower magnetic layer is laminated such that an end portion on the magnetic medium facing surface side overlaps with the convex portion. 2. The manufacturing method according to claim 1, wherein the side surface of the convex portion is formed to be inclined. 3. After the upper magnetic layer is laminated, the upper part of each thin film magnetic head at the end of the upper magnetic layer facing the magnetic medium is partially removed, and then the wafer is cut. The manufacturing method according to claim 1 or 2. 4. The throat height follow-up adjustment is performed by monitoring a change in the pole length based on at least the shape of the convex portion.
The manufacturing method according to item.