JPH11339225A - Manufacturing method for magnetoresistance effect thin-film magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately manufacture a write upper pole (embedded pole), having a narrow track width in a magnetoresistance effect thin film magnetic head. SOLUTION: After a resist is formed so that the width of a write upper ploe 22 becomes larger than that of the final shape of the pole, the write pole 22 is formed by plating. Next, a first milling work which shaves off only the vertical directions of the write upper pole and continuously a second milling work to mainly shave off the width direction of the pole. The write upper pole achieves a mask function in the first and second milling works, and a write lower pole 20 having the same width as that of the upper pole 22 is formed. Execution times for the first and second milling works are properly decided, in accordance with heights and widths of the write upper pole 22 and the write lower pole 20 which are to be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetoresistive thin-film magnetic head used for a magnetic disk storage device (hard disk) or the like.

[0002]

2. Description of the Related Art This type of magnetoresistive thin-film magnetic head has a reproducing head and a recording head laminated on the reproducing head. The reproducing head has a configuration in which a magnetoresistive element (MR element, GMR element) is arranged at a position facing the recording medium facing surface within a reproducing gap between the lower shield and the upper shield. For the recording head, a coil is arranged between the lower core and the upper core, also using the upper shield of the reproducing head as the lower core, and writing is performed at a position facing the recording medium facing surface between the upper core and the lower core. It has a configuration in which a gap is formed. In this structure, since the lower core of the recording head is also used as the upper shield of the reproducing head, the lower core is formed wider than the upper core. For this reason, the write magnetic field induced in the write gap between the upper core and the lower core during recording expands on the lower core side, and has a problem that the track density is reduced.

[0003] Accordingly, as shown in FIG.
A projection having a rectangular cross section is formed at a position opposed to the lower core 3 and is used as a lower writing pole 54 and a tip 5 of an upper core 5 is formed.
No. 3 proposed a magnetoresistive thin-film magnetic head in which a write upper pole 55 (buried pole) made of a material having a high magnetic permeability is formed at a position facing the write lower pole 54. The head is
The write upper pole 55 having a high magnetic permeability and the protrusion having a rectangular cross-section and having the same width as the write upper pole 55 and the write lower pole 54 can suppress the spread of the write magnetic field.

The upper write pole 55 and the lower write pole 54 are formed by milling. That is, first, as shown in FIG. 10A, a base plating layer 58 made of the same material as the upper write pole 55 (see FIG. 10B) is formed on the insulating film forming the write gap 56, A resist 60 is formed on a portion other than the shape of the writing pole 55 to be formed thereon by applying a resist and removing the resist 60 by exposure and development. Next, as shown in FIG. 10B, a high magnetic permeability material is plated on a portion where the resist 60 is not present, and then the resist 60 is removed to form a pole 55 for writing. Thereafter, ion milling in the height H direction of the upper write pole 55 is performed to form the lower write pole 54 using the upper write pole 55 as a mask (FIG. 10).
(3)).

[0005]

In the above-described process of forming the write pole, the write upper pole 55 is
It is shaved during the milling shown in (2) and its height decreases (H> h). Therefore, it is necessary to form the upper pole 55 for writing before milling by a height (Hh) that is reduced by milling, so that the base plating layer 58 is formed.
The thickness L of the resist 60 applied on the substrate becomes large (for example, 4 to 7 μm). If the thickness L of the resist 60 is large, the exposure amount when the resist is removed by exposure and development cannot be reduced.
5 (that is, the track width), it is difficult to cut (remove) with high accuracy. For example, with a current exposure device, the cut width W of a resist having a film thickness of 7 μm cannot be reduced to 0.9 μm or less. In addition, when a large number of such heads are formed on a wafer,
As shown in FIG. 11, as the cut width W of the resist approaches the exposure resolution limit C0, the variation of the cut width W (3σ).
Becomes larger. Since 3σ ≦ 0.2 is required in the practical range, the narrowest width of the write pole 55 for mass production is about 1.5 μm, and there is a problem that the write pole with a narrow track width cannot be mass-produced. .

Accordingly, an object of the present invention is to provide, for example, 0.4 μm.
An object of the present invention is to provide a method of manufacturing a magnetoresistive thin-film magnetic head capable of accurately mass-producing a write upper pole and a write lower pole having a narrow track width of m.

[0007]

SUMMARY OF THE INVENTION The present invention achieves the above object by forming in advance a write upper pole which is larger in width and height than a write upper pole to be formed and milling the write upper pole in a height direction and a width direction. Is what you do.

That is, a first feature of the present invention is that, in the forming step of the upper write pole and the lower write pole, a step of forming a write gap made of an insulating film on the upper shield and a step of forming the write gap on the write gap A step of applying a resist to a film thickness that forms a write upper pole higher than the write upper pole, a step of removing the resist by a width larger than the width of the write upper pole on which the resist is to be formed, and a step of writing to a portion where the resist has been removed. It is intended to include a step of forming an upper pole and a milling step of milling the formed upper write pole by a predetermined amount in the height and width directions to form an upper write pole and a lower write pole to be formed.

According to the first feature, the film thickness and the removal width of the resist are adjusted so that the writing pole which is larger not only in the height direction but also in the width direction with respect to the writing pole to be finally formed. It is formed by plating or the like. Then
The formed upper write pole is cut in the height and width directions by milling to obtain an upper write pole and a lower write pole to be formed. Accordingly, the width of the resist removal can be made relatively large, so that the accuracy of the removal width does not matter. In addition, since the side surface of the write upper pole is milled and cleaned, the end face of the pole is formed sharply, and a magnetoresistive thin film magnetic head that suppresses disturbance of magnetic flux at the write edge of the pole can be obtained.

[0010] A second feature of the present invention is that a milling step is performed.
A first milling step of milling the upper write pole and the insulating film only in the height direction of the upper write pole, and a second milling step of milling the upper write pole simultaneously in the height direction and the width direction of the same write pole. is there. According to this feature, the management of the milling process when forming the write pole is facilitated.

[0011]

FIG. 1 is a perspective view and FIG. 2 is a longitudinal sectional view of a magnetoresistive thin-film magnetic head according to an embodiment of the present invention. Protective layer 11, lower shield 12, lower reproducing gap 13
Are sequentially stacked. A pair of left and right bias magnet films 14 a and 14 b and the electrically conductive film 1
Films 5a and 15b face each other with a trapezoidal groove M (see FIG. 3A) interposed therebetween. The bias magnet films 14a,
14b and the electrically conductive films 15a and 15b form a pair of leads 16a and 16b.

A thin film MR element 17 is arranged between the pair of leads 16a and 16b (within the trapezoidal groove M). The MR element 17 is formed over the inclined surface of the trapezoidal groove M formed by the leads 16a and 16b and the upper surface of the lower reproduction gap 13 exposed at the bottom of the trapezoidal groove M. Also, the end of the thin film of the MR element 17 is exposed to the facing surface A of the magnetic recording medium (media) (refer to FIG. 2; hereinafter, referred to as “magnetic recording medium facing surface A”). It is perpendicular to the facing surface A. This MR element 1
Reference numeral 7 denotes a laminate of the MR layer, the spacer film, and the SAL.

MR element 17, left and right leads 16a, 16
The upper reproduction gap 18 is formed on the lower reproduction gap 13 exposed at and around the b. The upper reproduction gap 18 and the lower reproduction gap 13 constitute a reproduction gap. Therefore, the MR element 17 is arranged in the reproduction gap. An upper shield and lower core 19 is stacked on the upper gap 18 for reproduction. At a position on the upper surface of the upper shield / lower core 19 perpendicular to the thin film surface of the MR element 17 and at a position corresponding to a write upper pole 22 to be described later, a projection (convex portion) 20 having a rectangular cross section called a write lower pole is provided. (Hereinafter, referred to as a writing lower pole 20). The width of the lower write pole 20 is the same as the width W of the upper write pole 22 described later. Further, the thickness of the upper shield / lower core 19 gradually decreases as the distance from the lower write pole increases. The lower shield 12 to the upper shield and lower core 19 constitute a reproducing head.

On the lower write pole 20, a write gap 21 made of an insulating film is formed. A write upper pole (buried core) 22 is formed on the write gap 21 and on the side A facing the magnetic recording medium. The upper write pole 22 has a predetermined width W in a layer surface direction (lateral direction, width direction) of each layer, a predetermined height in a direction perpendicular to the layer surface (vertical direction), and a predetermined length in a direction perpendicular to the magnetic recording medium facing surface A. It has a substantially rectangular parallelepiped shape having a height.

The upper core 23 has a tip portion provided directly above the upper write pole 22 and has a thickness substantially the same as that of the tip portion and extends in a layer surface direction at a position retreated from the magnetic recording medium facing surface A. Has an arcuate shape (see FIG. 2). The upper core 23 is connected to the upper shield / lower core 19 at the arcuate end portion to form a magnetic path, and a coil 25 embedded in the insulating layer 24 penetrates between the upper core 23 and the upper shield / lower core 19. ing. In addition, the protective layer 2
6 (see FIG. 2) covers the periphery of the upper core 23 and the insulating layer 24. The upper shield and lower core 19 to the upper core 2
Up to 3 constitute a recording head.

One embodiment of the method of manufacturing a magnetic head according to the present invention shown in FIG. 1 includes the steps shown in FIGS. That is, (1) As shown in FIG. 3 (1), Altic (Al ₂ O ₃
-A wafer made of a ceramic material such as TiC)
An insulating film 11 such as alumina (Al ₂ O ₃ ) is formed on a substrate 10 which is cut later to form a slider, and a lower shield 1 which is a soft magnetic film such as permalloy is formed on the insulating film 11.
After depositing 2, an insulating film (alumina or the like) forming the lower reproduction gap 13 is deposited by sputtering or the like. A pair of bias magnet films 14a, 14b made of CoCrPt or the like and a pair of electric conductive films 15a, 15b made of W, Ta, Nb, etc. are laminated on the lower reproducing gap 13 by sputtering, vapor deposition or electroplating. To form a groove M. The bias magnet films 14a and 14b and the electric conductive films 15a and 15b are connected to a pair of leads 16a and 16b.
Make

Next, a thin-film MR element (MR element) is provided between the pair of leads 16a and 16b (within the trapezoidal groove M).
ment) 17 is formed. The MR element 17 is made of CoZr.
After laminating spacers made of M (Nb, Mo, etc.) soft magnetic films made of SAL, Ti, etc., and MR films made of NiFe, etc., unnecessary portions are removed and cut into a rectangular planar shape. As a result, the left and right ends of the MR element 17 are cut in the middle of the inclined surfaces of the leads 16a and 16b.

(2) Next, as shown in FIG.
An insulating film made of alumina or the like is deposited on the MR element 17, the left and right leads 16a and 16b, and the lower reproducing gap 13 exposed therearound to form an upper reproducing gap. (3) Next, as shown in FIG.
8, a soft magnetic film such as NiFe is deposited to form a base plating layer 19a. (4) Thereafter, as shown in FIG. 4D, a soft magnetic film such as NiFe equivalent to the base plating layer 19a is deposited to a predetermined thickness by electroplating or the like to form the upper shield / lower core 19. I do. (5) Next, as shown in FIG. 4 (5), the upper surface of the upper shield / lower core 19 is polished so that the upper shield / lower core 19 is polished.
Is flattened.

(6) Subsequently, as shown in FIG.
An insulating film made of alumina or the like is deposited on the upper shield / lower core 19 by sputtering or the like to form a write gap 21. (7) Next, as shown in FIG. 5 (7), the upper end of the write gap 21 (the surface A facing the magnetic recording medium in FIG. 2)
Writing pole 2 made of a high magnetic permeability material such as a nickel-iron alloy (permalloy) containing 40 to 55% by weight of a nickel component on its side, that is, at a position facing the magnetic recording medium facing surface A).
2a is formed. The writing pole 22a at this time is
1 and 8 (D), the width W (left and right when the MR element 17 is below when viewed from the magnetic recording medium facing surface A) of the right and left write upper poles 22 (to be formed) finally obtained. Width in the direction (layer direction of each layer), FIG. 1 or FIG.
The lower write pole 20 shown in (D) is formed so as to have a width W0 that is larger by a predetermined width than the upper shield / lower core 19 has a cross section of a rectangular protrusion when the cross section is regarded as a rectangular protrusion. (See FIG. 8A). Also, in the height direction (the direction perpendicular to the layer surface such as the write gap 21), the height H of the write upper pole 22 finally obtained (the height H from the upper surface of the write gap 21) is a predetermined amount. It is formed to have a large height H0. Specifically, (A) When forming the writing pole 22a, FIG.
As shown in FIG. 5A, a plating base layer 22b of the same material as the write pole 22a shown in FIGS.
Is formed on the upper surface of the write gap 21.
After a resist having a film thickness L0 is applied thereon, it is cut by exposure (to remove the resist) so as to have the above-described predetermined width W0, thereby forming a pair of resists Ra and Rb. The film thickness L0 is formed so that the distance from the upper surface of the write gap 21 to the upper surface of the resist R becomes H0 described above.

(B) Next, as shown in FIG.
A write pole 22a is formed by electroplating on a portion where the resists Ra and Rb do not exist, and the resists Ra and Rb are formed.
Is removed. At this point, the state shown in FIG. 5 (7) is obtained.

(8) Next, as shown in FIGS. 5 (8) and 8 (C), a first engraving milling process (irradiation with a plasma-formed inert gas (argon ion)) is performed. In this case, the ion milling angle (the ion irradiation angle with respect to the height direction of the writing pole 22a and the irradiation angle with respect to the vertical direction) θ1 is in the range of 30 ° to 60 °. That is, in the first engraving milling process, the angle at which only the height direction of the upper pole 22a is milled is set. As a result, only the height direction of the upper write pole 22a is shaved, and the height direction (thickness direction, layer surface vertical direction) of the upper shield / lower core 19 is shaved using the upper write pole 22a as a mask. On the upper shield / lower core 19 and below the upper write pole 22a, a projection (a part of the later lower write pole 20) having a rectangular cross section having the same width as the current upper write pole 22a is formed. You. The projection having a rectangular cross section protruding from the upper surface of the upper shield and lower core 19 is called a mesa (hill), and such a structure is called a mesa structure. In addition, upper shield and lower core 1
9 has an inclined surface 19 inclined downward from the base of the protrusion.
a. Since the plating base layer 22b and the upper pole 22a are made of the same material, the upper pole 22 is finally formed (see FIG. 8D).

(9) Subsequently, FIGS. 6 (9) and 8 (D)
A second engraving milling process is performed as shown in FIG. In this case, the ion milling angle θ2 is set in a range from 60 ° to 75 °. That is, in the second engraving milling, the width direction of the upper pole 22a is set to a milling angle for mainly cutting.
Thereby, the width direction of the write pole 22a is cut (the height direction is also slightly cut). If the second milling angle θ2 is too large, the portion to be milled is shaded by an adjacent pole (when a large number of heads are processed adjacently) or a jig for pressing and fixing the wafer, and the write pole 22a
In order to increase the variation in the amount of shaving in the width direction of the above, it is desirable that the angle be at most about 75 °. If the milling angle θ2 is too small, the cutting in the height direction becomes too large relative to the width direction, and the track width W cannot be reduced too much. Therefore, the milling angle θ2 should be 60 ° or more. desirable. Thus, the upper write pole 22 having a narrow track width W and the lower write pole 20 having the same width W are formed as shown in FIGS. 6 (10) and 8 (D).

(11) Next, as shown in FIG. 7 (11), an insulating film 27 made of alumina or the like is deposited on the entire surface by sputtering or the like, and the write pole 22 is buried. (12) Subsequently, as shown in FIG. 7 (12), the deposited insulating film 27 is polished to the upper surface of the tip of the upper write pole 22 to flatten the upper surface of the insulating film 27. Thereby, the periphery of the upper pole 27 for writing is surrounded by the insulating film 27. (13) After that, as shown in FIG. 1, after forming the insulating layer 24 and the coil 25 on the insulating film 27, the upper core 23 is formed so as to straddle the insulating layer 24 and the coil 25.
Finally, as shown in FIG. 2, a shield type magnetoresistive thin-film magnetic head is formed by covering the protective film 26.

When the milling time is changed in the first and second engraving milling processes in the above-mentioned steps (8) and (9), the reduction amount of the write-in pole width and the mesa depth H are changed.
M, that is, the writing pole height HM (writing pole 20
HM from the upper surface of the upper shield and lower core, Fig. 8 (D)
Table 1 shows the results of measurement of the change in the reference value. The first
The first milling angle θ1 in the engraving milling process (first milling process) is 40 °, and the second milling angle θ2 in the second engraving milling process (second milling process)
Was set to 65 °.

[0025]

[Table 1]

As is apparent from Table 1, according to the present manufacturing method, by appropriately selecting the times of the first and second engraving milling processes, the width W of the writing pole can be maintained without changing the mesa depth HM. Can have a predetermined width. In the case of this example, the maximum value of the reduction amount of the pole width on writing is 1.2 μm. This means that if a write pole having a width of 1.5 μm, in which the manufacturing variation accompanying the cutting of the resist is within an allowable range, is manufactured, the write pole having a very narrow track width of 0.3 μm can be accurately formed. It means that it can be processed.

In addition, since the width W of the pole upon writing is adjusted by milling, the variation 3σ is very good at 0.1 or less over the entire wafer, and the variation is independent of the pole width. In view of the fact that the width (track width) of the top pole on writing when the present invention is not used is 0.9 μm even at the narrowest, and in this case, the variation is very large, this manufacturing method is very It turns out that it is excellent.

Further, when a thick resist is exposed and cut, the scumming S shown in FIG. 10A remains at the bottom of the cut surface. Therefore, in the method not using the present invention, a defect F may remain on the side surface of the upper pole 55 as shown in FIG. On the other hand, in the present manufacturing method, even if the scumming S remains at the bottom of the cut surface of the resist (see FIG. 8A) and the defect F occurs on the side surface of the write pole 22a (see FIG. 8C), Since this is cut off by the second engraving milling, the defect F does not remain (see FIG. 3D). Therefore, according to the present manufacturing method, it is possible to obtain a magnetoresistive thin-film magnetic head that does not cause an error due to an abnormal write signal due to the defect F.

Further, in this manufacturing method, since the side face of the pole 22 on the writing is precisely cut by the second engraving milling process, the side face of the pole 22 is extremely sharp, and the disturbance of the magnetic flux at the writing edge is suppressed. A magnetoresistive thin-film magnetic head can be obtained.

In the above embodiment, the reproducing head is provided with the MR.
Although the element 17 is used, a so-called GMR element can be used instead. At this time, the structure of the reproducing head does not change at all.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a magnetoresistive thin-film magnetic head according to the present invention.

FIG. 2 is a longitudinal sectional side view of the magnetoresistive thin-film magnetic head shown in FIG. 1;

FIG. 3 is a diagram showing a manufacturing process of the magnetoresistive thin-film magnetic head shown in FIG.

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

FIG. 5 is a diagram showing a manufacturing process of the magnetoresistive thin-film magnetic head shown in FIG. 1;

FIG. 6 is a view showing a manufacturing process of the magnetoresistive thin-film magnetic head shown in FIG. 1;

FIG. 7 is a diagram showing a manufacturing process of the magnetoresistive thin-film magnetic head shown in FIG. 1;

FIG. 8 is a diagram showing a step of forming a write pole of the magnetoresistive thin-film magnetic head shown in FIG.

FIG. 9 is a perspective view of a magnetoresistive thin-film magnetic head which is the background of the present invention.

10 is a diagram showing a write pole forming step of the magnetoresistive thin film magnetic head shown in FIG.

FIG. 11 is a diagram showing a variation degree of a pole width on writing of a magnetoresistive thin-film magnetic head which is a background of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... board | substrate, 11 ... protective layer (insulating film), 12 ... lower shield, 13 ... reproduction lower gap, 17 ... MR element, 18 ... reproduction upper gap, 19 ... upper shield and lower core, 20 ... writing lower pole (mesa Structure), 21 ... write gap, 22
... write upper pole, 23 ... upper core, 25 ... coil.

Claims (2)

[Claims] 1. A reproducing head comprising a magnetoresistive element disposed between a lower shield provided on a substrate with an insulating film interposed therebetween and an upper shield forming a lower core, and a reproducing head positioned directly above the reproducing head. A magneto-resistive thin film comprising: a write upper pole provided on a top surface of a write lower pole formed by a part of the lower core via a write gap; and an upper core disposed on the upper surface of the write upper pole. In the method of manufacturing a magnetic head, the step of forming the upper write pole and the lower write pole includes: forming a write gap made of an insulating film on the upper shield; and forming the upper write pole to be formed on the write gap. Applying a resist to a thickness that forms a higher write pole, and only a width greater than the width of the write pole to form the resist Removing the resist; forming an upper write pole in the portion where the resist has been removed; milling the upper write pole by a predetermined amount in the height and width directions to form the upper write pole and the lower write pole And a milling step of forming a magnetoresistive thin-film magnetic head. 2. The method of manufacturing a magnetoresistive thin-film magnetic head according to claim 1, wherein said milling step comprises: milling said write pole only in a height direction.
A method of manufacturing a magnetoresistive thin-film magnetic head, comprising: a milling step; and a second milling step of simultaneously milling the upper pole in the height and width directions.