JP2009181641A - Magnetic recording head, composite thin film magnetic head, and magnetic disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording head, a composite thin film magnetic head and a magnetic disk device, which provide a sufficient recording field using a thin film and a wide dimension margin of a taper structure part. <P>SOLUTION: A main magnetic pole 11 has a tapered structure in a film in-plane direction, as well as a tapered structure part 12 as a thin laminated film where a taper angle changes in a film thickness direction in two stages at a first taper structure part 13 and a second taper structure part 14, so that the recording field monotonously increases with respect to a film thickness of the taper structure part 12, and taper angle dependency is reduced at a magnetic gradient. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic recording head, a composite thin film magnetic head, and a magnetic disk apparatus, and in particular, an improvement in recording magnetic field and an improvement in manufacturing margin in a composite thin film magnetic head used for recording / reproducing of a magnetic disk or the like. The present invention relates to a configuration for achieving both.

  In a magnetic disk device, data on a magnetic recording medium is read and written by a magnetic head. In order to increase the recording capacity per unit area of such a magnetic disk device, both in the track width direction and the bit length direction are used. It is necessary to improve the density.

  However, in the current in-plane recording method, when the bit length to be recorded is shortened, there is a problem that the surface recording density cannot be increased due to the thermal fluctuation of the magnetic recording medium, and as a method for solving these problems In order to further increase the density, a perpendicular recording method for magnetizing in a direction perpendicular to the magnetic recording medium is being put into practical use.

  Even in such a perpendicular recording system, it is necessary to concentrate the magnetic field distribution in a narrower range in order to increase the density. However, in the magnetic recording head, when the carriage arm rotates on the magnetic recording medium, it is adjacent to the magnetic recording head. The edge of the main pole protrudes to the track, and there is a problem of so-called side erasure in which information on the adjacent track is erased.

On the other hand, in recent years, by using a method using a main pole whose cross-sectional shape is an inverted trapezoidal shape as viewed from the medium facing surface (ABS surface), and a method of arranging shields called side shields on both sides of the main pole, Eliminates the erase problem.
However, both methods reduce the output of the recording magnetic field induced from the main magnetic pole to the magnetic recording medium. Therefore, if the track pitch is further reduced from the present level, there is a concern about the occurrence of writing failure due to the decrease in the output of the recording magnetic field. .

  Therefore, as a means to avoid the occurrence of write defects due to a decrease in the output of the recording magnetic field, a method of compensating the recording magnetic field by increasing the thickness of the main magnetic pole part by tapering from the medium facing surface of the main magnetic pole to the rear part is proposed. (For example, refer to Patent Document 1 or Patent Document 2).

Here, a conventional magnetic recording head having a tapered main magnetic pole will be described with reference to FIG.
See FIG.
FIG. 7 is a schematic cross-sectional view of a main part of a conventional magnetic recording head having a tapered main magnetic pole. The taper structure has a thickness PL at a position separated from the ABS surface of the main magnetic pole 61 by PH (pole height). A portion 62 is provided.
In addition, a trailing shield 63 integrated with a return yoke (not shown) is provided on the side facing the ABS side on the trailing side.

As described above, the use of an inverted trapezoidal main pole and the use of a tapered main pole can produce a magnetic recording head that achieves both an increase in the recording magnetic field and a reduction in the erase magnetic field, but the magnetic field gradient is also reduced when performing magnetic recording. It becomes a problem.
That is, if the magnetic field gradient is small, the edge of the recorded bit is disturbed, so that the noise increases and is not desirable as a signal.

Therefore, a magnetic field gradient is increased by attaching a shield called a trailing shield 63 on the trailing side of the single pole head.
JP-A-2005-302281 JP 2005-166259 A

  However, as a result of diligent research by the present inventor, the recording magnetic field can be increased by increasing the thickness PL of the main magnetic pole taper structure portion. However, regarding the magnetic field gradient, the thickness PL of the main magnetic pole taper structure portion can be increased. As the magnetic field gradient increases, the magnetic field gradient also increases. However, it has been found that the magnetic field gradient starts to decrease when the magnetic field gradient has a peak at a certain point and when the thickness of the tapered portion is further increased.

In addition, the larger the taper angle θ of the taper structure portion, the larger the change with respect to the film thickness PL of the taper structure portion. The larger the taper angle θ, the higher the recording magnetic field and the peak of the magnetic field gradient can be obtained with the smaller film thickness PL. The value at the slope peak is smaller.
It has also been found that when the film thickness PL exceeds the thickness at which the magnetic field gradient is maximized, the magnetic field gradient is rapidly decreased.

See FIG.
FIG. 8 is an explanatory diagram of the dependence of the recording magnetic field on the film thickness of the taper structure. Here, simulation results are shown for taper angles θ of 25 °, 45 °, 63 °, and 90 °. In addition, the recording magnetic field is normalized by PL = 0, that is, a value when no taper structure is provided.
As is apparent from the figure, the recording magnetic field shows a monotonically increasing tendency as the film thickness PL increases, and it can be seen that the larger the taper angle θ, the larger the recording magnetic field.

See FIG.
FIG. 9 is an explanatory diagram of the film thickness dependence of the magnetic field gradient of the taper structure, and again shows the simulation results when the taper angle θ is 25 °, 45 °, 63 °, and 90 °. In addition, the magnetic field gradient is normalized by PL = 0, that is, a value when the taper structure is not provided.

As is apparent from the figure, the larger the taper angle θ, the more the magnetic field gradient peak can be obtained with a small film thickness PL, and the magnetic field gradient tends to decrease sharply.
In addition, when the taper angle θ is 45 °, there is a tendency to slightly decrease from the peak and the peak value, but when the taper angle θ is 25 °, a saturation tendency is observed in the range where the film thickness PL is up to 150 nm. There is as much as possible.

  For manufacturing purposes, it is desirable that the thickness of the taper structure is thin, but considering the manufacturing error of the taper angle θ and the taper film thickness PL, changes in the recording magnetic field and magnetic field gradient are not too sensitive to the taper structure dimensions. It is desirable.

  Therefore, a trailing shield type perpendicular magnetic recording head having a main magnetic pole having a tapered structure portion can achieve both a sufficient recording magnetic field with a small film thickness and a wide dimensional margin of the tapered structure portion. An object is to provide a perpendicular magnetic recording head.

  This magnetic recording head is required to have a taper structure in which the main magnetic pole has a taper structure in the film in-plane direction and the taper angle changes in two stages in the film thickness direction.

From another point of view, the composite thin film magnetic head is required to be laminated with the above-described perpendicular recording head and reproducing head.
Furthermore, from another point of view, the magnetic disk device is required to be equipped with the above-described composite thin film magnetic head.

  According to the disclosed magnetic recording head, the taper structure provided on the main pole has a two-stage structure, so that the increase of the recording magnetic field maintains the monotonically increasing characteristic with respect to the film thickness of the taper structure, and the magnetic field gradient depends on the taper angle. Can be reduced.

  This also eliminates the need for high accuracy in controlling the taper angle in manufacturing, and makes it possible to obtain a desired recording magnetic field and magnetic field gradient only by controlling the film thickness, thereby increasing the manufacturing margin.

  In addition, the magnetic field gradient has a peak when the film thickness is thinner than in the conventional case where the taper angle is constant, and the recording magnetic field at that time is equivalent to the case where the taper angle is constant. Since the film thickness can be small, manufacturing is facilitated.

Here, an embodiment of the present invention will be described with reference to FIGS.
See Figure 1
1A and 1B are schematic explanatory views of a perpendicular magnetic recording head according to an embodiment of the present invention. FIG. 1A is a schematic plan view of a main part, and FIG. 1B is a schematic cross-sectional view of the main part. FIG.
In the main magnetic pole 11 constituting the perpendicular magnetic recording head in this case, the air bearing surface (ABS surface) facing the magnetic recording medium is tapered in the in-plane direction at a distance called NH (neck height).

Further, a taper structure 12 having a two-stage structure is provided in the film thickness direction of the main magnetic pole 11 from a distance of PH (pole height) from the ABS surface. The taper structure 12 has a thickness of PL ₁ . The first taper structure portion 13 has a taper angle θ ₁ and the second taper structure portion 14 has a thickness PL ₂ and a taper angle θ ₂ .
A trailing shield 15 is provided on the trailing side.

At this time, the taper angle theta ₁ of the first tapered structure portion 13, and sets the largest recording magnetic field is θ ₁ = 90 ° ± 10 ° which is obtained as shown in FIG. 8, the film thickness PL ₁ is 9 As shown in FIG. 4, the thickness is set in the vicinity of the magnetic field gradient before reaching the peak value. For example, the thickness is set to 40 nm ± 5 nm.
Note that θ ₁ = 90 ° ± 10 ° is 90 ° as a design value, and ± 10 ° means a manufacturing error.
Further, in this case, NH and PH are generally the same distance, but need not be the same distance. In that case, NH> PH is set.

See Figure 2
FIG. 2 is an explanatory diagram of the film thickness dependence of the two-stage taper structure portion of the recording magnetic field. Here, PL ₁ = 40 nm and the taper angle θ ₂ of the second taper structure portion is 27 ° and The simulation results for the case of 45 ° are shown, and the recording magnetic field is normalized by PL = 0, that is, the value when the tapered structure portion is not provided.

As is apparent from the figure, the recording magnetic field shows a monotonically increasing tendency as the film thickness PL (= PL ₁ + PL ₂ ) increases, and the recording magnetic field overlaps with the case where the taper angle θ is constant at 90 °, and after 40 nm. It can be seen that it does not depend on the taper angle θ ₂ after switching.

In addition, by providing the first taper structure portion of θ ₁ = 90 °, the film thickness PL required to reach the required recording magnetic field is PL with a small taper angle of 27 ° and 45 ° in the structure of the conventional example. It can be seen from the comparison with FIG. 8 that the thickness is thinner than the increase.

See Figure 3
FIG. 3 is an explanatory diagram of the film thickness dependence of the two-stage tapered structure portion of the magnetic field gradient. Here again, PL ₁ = 40 nm and the taper angle θ ₂ of the second tapered structure portion is 27 ° and The simulation results for the case of 45 ° are shown, and the recording magnetic field is normalized by PL = 0, that is, the value when the tapered structure portion is not provided.

As is apparent from the figure, by providing the second taper structure portion with the taper angle θ ₂ and switching the taper angle, the change in the magnetic field gradient becomes more gradual than when the taper angle is constant at 90 °, and the PL dimension It can be seen that the margin has increased.

It can also be seen from the comparison with FIG. 9 above that the magnetic field gradient can be obtained at a smaller PL than when the PL is increased with a small taper angle in the structure of the conventional example.
In this case, the taper angle θ ₂ of the second tapered structure portion is preferably in the range of 20 ° to 55 °, and more preferably in the range of 27 ° to 45 °.

As described above, the _first magnetic taper portion 13 having a thickness PL ₁ of 40 nm ± 5 nm and a taper angle θ ₁ of 90 ° ± 10 ° on the main magnetic pole, and a taper angle θ ₂ of 20 ° to 55 with a thickness PL ₂ . By providing the taper structure portion composed of the second taper structure portion 14 °, an appropriate value can be obtained for both the recording magnetic field and the magnetic field gradient at the small thickness of the taper structure portion, and a taper thickness margin can be secured.

  Further, the taper angle dependence after switching of the recording magnetic field can be ignored, and the magnetic field gradient changes gradually in the range of the taper angle from 20 ° to 55 °, as seen from the characteristic extrapolation in FIG. Since it is difficult to see, a taper angle margin can be secured.

Based on the above, the composite thin film magnetic head according to the first embodiment of the present invention will now be described with reference to FIGS. 4 and 5. Only the main magnetic pole forming process will be described with reference to FIG. explain.
See Figure 4
FIG. 4 is an explanatory diagram of the configuration of the composite thin film magnetic head according to the first embodiment of the present invention. The upper diagram is a schematic front view seen from the ABS surface, and the lower diagram is along AA ′ in the front view. FIG.
In addition, description is abbreviate | omitted about the plating base layer in an electrolytic plating process.
First, the lower magnetic shield layer 21, the TMR film 22, the magnetic domain control film 23, and the Al ₂ O film are placed on an Al ₂ O ₃ —TiC substrate, which is the base of the slider, via an Al ₂ O ₃ film (all of which are not shown). _Three films 24 and an upper magnetic shield layer 25 are provided.

Next, after an Al ₂ O ₃ film 26 is provided on the entire surface of the upper magnetic shield layer 25, a main magnetic pole made of NiFe having a thickness of, for example, 500 nm is formed on the Al ₂ O ₃ film 26 by using a selective electrolytic plating method. An auxiliary layer 27 is provided.

Next, after depositing an Al ₂ O ₃ film on the entire surface using a sputtering method, and planarizing using a CMP (Chemical Mechanical Polishing) method, the recess on the side facing the head medium is embedded in Al ₂ O _3. The main magnetic pole 29 made of a CoNiFe film having a thickness of, for example, 100 nm is formed on the entire surface using the selective electrolytic plating method.

Next, by performing ion milling using Ar ions from a tilt direction using a resist pattern (not shown) as a mask, the tips of the CoNiFe layer to the Al ₂ O ₃ buried layer 28 are selectively removed, for example, A main pole tip 30 having a reverse trapezoidal cross section with a width of 60 nm on the trailing side is formed.
The length PH in the element height direction of the main magnetic pole tip 30 is, for example, 60 nm.
Next, an Al ₂ O ₃ film is again deposited on the entire surface using a sputtering method, and then planarized using a CMP method to form an Al ₂ O ₃ buried layer 31.

Refer to FIG.
Next, the CoNiFe film 32 having a thickness of, for example, 120 nm is formed again using the selective electrolytic plating method.

Refer to FIG.
Next, with the resist pattern 33 as a mask, the CoNiFe film 32 is removed by a thickness of 60 nm by ion implantation that irradiates Ar ions from the 45 ° direction.
At this time, a 45 ° tapered portion 34 is formed in the shaded portion of the resist pattern 33.

Refer to FIG.
Next, after removing the resist pattern 33, the resist pattern 35 is provided again, and the CoNiFe film 32 is removed by a thickness of 40 nm by ion milling that irradiates Ar ions from the normal direction with respect to the main surface. A two-stage tapered structure portion 36 is formed, which includes a first tapered structure portion 37 having an angle of 90 ° and a thickness of 40 nm and a second tapered structure portion 38 having a taper angle of 45 ° and a thickness of 60 nm.

Again see Figure 4
Next, a gap layer 39 made of a nonmagnetic material, for example, Al ₂ O ₃ and having a thickness of 30 to 100 nm, for example, 40 nm, is provided on the entire surface by sputtering.
Next, Cu is selectively formed on the gap layer 39 using a selective electrolytic plating method to form a planar spiral write coil 40.

Next, a photoresist is provided so as to cover the write coil 40, and this photoresist is used as the coating insulating film 41. Then, a Ni—Fe layer is deposited again using the selective electroplating method and deposited on the coating insulating film 41. The Ni—Fe layer thus formed is used as the upper return yoke 42, and the Ni—Fe layer deposited on the side surface of the covering insulating film 41 on the side facing the head medium is used as the trailing shield layer 43.
The write coil 40 has a structure wound around a connection portion 44 that magnetically connects the main magnetic pole 29 and the return yoke 42.
Finally, the basic structure of the composite thin-film magnetic head is obtained by cutting the head medium facing surface side and polishing the ABS surface so as to adjust the element height.

  Since the perpendicular recording head part of the composite thin film magnetic head of the present invention is provided with the taper structure part 36 having a two-stage structure on the main pole, the taper angle dependency after switching in the recording magnetic field can be ignored, and the film thickness can be controlled. It becomes possible to obtain a desired recording magnetic field and magnetic field gradient only.

  In addition, when the trailing shield is provided to increase the magnetic field gradient, the taper angle of the second taper structure is set in a range where the magnetic field gradient is thin and does not take a maximum value. A magnetic field gradient can be formed, thereby reducing the disturbance of recorded bit edges and reducing noise.

Next, a magnetic disk device according to a second embodiment of the present invention will be described with reference to FIG.
See FIG.
FIG. 6 is a schematic plan view of the magnetic disk device according to the second embodiment of the present invention, and shows the relationship between the magnetic disk and the magnetic head.
A slider 53 on which the composite thin film magnetic head 50 of the first embodiment is formed is fixed to the tip of a suspension arm 52 supported by the rotary actuator 51.
Although not shown, a slider 53 is fixed to the front end of the suspension with a support called a gimbal.

Information is recorded on and reproduced from the magnetic disk 54 rotating in the rotation direction shown in the figure by the composite thin-film magnetic head 50 provided at the end of the slider 53.
As the rotary actuator 51 rotates, the composite thin-film magnetic head 50 can be moved to different radial positions on the magnetic disk 54 and positioned.

At this time, concentric recording tracks 55 are formed on the magnetic disk 54.
Increasing the density in the track width direction means that the concentric recording tracks 55 are formed with a plurality of recording tracks 55 at a certain narrow interval. The angle formed by the head and the recording track, that is, the yaw angle changes variously, and changes within a range of ± 15 to 20 ° at the maximum.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the configurations and conditions described in the embodiments, and various modifications are possible. For example, in the above embodiments, The taper angle of the second taper structure portion is 45 °, but is not limited to 45 °, and may be in the range of 20 ° to 55 °, more preferably in the range of 27 ° to 45 °. good.

  In each of the above embodiments, a write coil is provided on the trailing side, but a write coil may be provided on the leading side to form a double coil structure, or a helical coil around which the main magnetic pole is wound. good.

  In the above embodiment, only the trailing shield is provided, but side shields may be provided on both sides of the main magnetic pole tip.

Regarding the embodiment including the first example and the second example, the following additional notes are disclosed.
(Supplementary note 1) A magnetic recording head having a taper structure in which the main magnetic pole has a taper structure in the in-plane direction and the taper angle changes in two stages in the film thickness direction.
(Supplementary Note 2) Of the taper structures changing in two stages, the taper angle of the lower first taper structure is 90 ° ± 10 °, and the taper angle of the upper second taper structure is 20 °. The magnetic recording head according to supplementary note 1, wherein the magnetic recording head is ˜55 °.
(Additional remark 3) The magnetic recording head of Additional remark 2 with which the front-end | tip of a said 2nd taper structure corresponds with the upper end part of a said 1st taper structure.
(Supplementary note 4) In Supplementary note 2 or 3, the film thickness of the first taper structure is a film thickness in a range of ± 5 nm with respect to the film thickness at which the maximum value of the film thickness dependence of the magnetic field gradient of the main magnetic pole appears. The magnetic recording head described.
(Additional remark 5) The position where the inclination of the taper structure starts in the film in-plane direction is the same as the position where the inclination of the taper structure where the taper angle changes in two stages also in the film thickness direction. 5. The magnetic recording head according to any one of 4 above.
(Supplementary note 6) The magnetic recording head according to any one of supplementary notes 1 to 5, wherein a trailing shield is provided on a side where the tapered structure changing in two stages is formed.
(Additional remark 7) The composite type thin film magnetic head which laminated | stacked the perpendicular | vertical recording head of any one of Additional remark 1 thru | or 6, and the reproducing head.
(Supplementary Note 8) A magnetic disk device on which the composite thin film magnetic head according to Supplementary Note 7 is mounted.

  As a practical example of the present invention, a recording head of a composite thin film magnetic head constituting an HDD is typical, but it is also applicable to a perpendicular recording head without a reproducing head using a magnetoresistive effect element. It is.

1 is a schematic configuration explanatory diagram of a perpendicular magnetic recording head according to an embodiment of the present invention. FIG. It is explanatory drawing of the film thickness dependence of the taper structure part of the two-step structure of a recording magnetic field. It is explanatory drawing of the film thickness dependence of the taper structure part of the two-stage structure of a magnetic field gradient. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration explanatory diagram of a composite thin film magnetic head according to a first embodiment of the present invention. It is explanatory drawing of the formation process of the taper structure part of the composite type thin film magnetic head of Example 1 of this invention. FIG. 6 is a schematic plan view of a magnetic disk device according to a second embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a main part of a conventional magnetic recording head including a tapered main magnetic pole. It is explanatory drawing of the film thickness dependence of the taper structure part of a recording magnetic field. It is explanatory drawing of the film thickness dependence of the taper structure part of a magnetic field gradient.

Explanation of symbols

11 main pole 12 tapered structure part 13 first taper structure 14 second tapered structure 15 trailing shield 21 lower magnetic shield layer 22 TMR film 23 domain control film 24 Al ₂ O ₃ film 25 upper magnetic shield layer 26 Al ₂ O ₃ film 27 main magnetic pole auxiliary layer 28 Al ₂ O ₃ buried layer 29 main magnetic pole 30 main magnetic pole tip 31 Al ₂ O ₃ buried layer 32 CoNiFe film 33 resist pattern 34 taper 35 resist pattern 36 taper structure 37 first Tapered structure portion 38 Second taper structure portion 39 Gap layer 40 Write coil 41 Cover insulating film 42 Return yoke 43 Trailing shield layer 44 Connection portion 50 Composite thin film magnetic head 51 Rotary actuator 52 Suspension arm 53 Slider 54 Magnetic disk 55 Recording track 61 Main magnetic pole 62 Tapered structure 3 trailing shield

Claims (5)

A magnetic recording head having a taper structure in which a main magnetic pole has a taper structure in a film in-plane direction and a taper angle changes in two stages in a film thickness direction. Of the taper structures changing in two stages, the taper angle of the lower first taper structure is 90 ° ± 10 °, and the taper angle of the upper second taper structure is 20 ° to 55 °. The magnetic recording head according to claim 1. 3. The magnetic recording head according to claim 1, further comprising a trailing shield on a side on which the taper structure changing in two stages is formed. 4. A composite thin film magnetic head in which the perpendicular recording head according to claim 1 and a reproducing head are stacked. 5. A magnetic disk drive equipped with the composite thin film magnetic head according to claim 4.

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