JP2008010023A - Manufacturing method of thin film magnetic head - Google Patents

Abstract

The size of a head element is reduced in response to an increase in recording density of a magnetic disk device. Along with the miniaturization of the element size, how to reduce the processing damage caused by the polishing process on the magnetoresistive element is a very important issue.
A magnetic field generating mechanism 632 is mounted on a work holding jig 63, and a row bar 50 is attached to the magnetic field generating mechanism 632 with an adhesive to reinforce the magnetic moment of the pinned layer 24 of the GMR element 12. The magnetic field generation direction of the magnetic field generation mechanism 632 coincides with the magnetization direction 26 b of the pinned layer 24. Next, the surface of the row bar 50 that will later become the air bearing surface is pressed against the polishing surface plate 64 having a predetermined shape with a predetermined force, and the polishing surface plate 64 is rotated and simultaneously the workpiece holding jig 63 is swung. The mechanism 61 is swung in the radial direction of the surface plate to polish and remove a predetermined processing amount.
[Selection] Figure 1

Description

  The present invention relates to a method of manufacturing a thin film magnetic head mounted on a magnetic disk device.

In recent years, the capacity of a magnetic disk device used as an external recording device of a computer has been increased, and its recording density has been increasing year by year. The magnetic disk device is roughly composed of a magnetic disk and a magnetic head (thin film magnetic head). The thin film magnetic head includes an inductive magnetic transducer (inductive element) as a recording element and a magnetoresistive (MR) element as a reproducing element. As a magnetoresistive effect element, a GMR (Giant Magnetoresistive) element is generally used, but a TMR element is being put into practical use.
A thin film magnetic head is generally manufactured by the following manufacturing method. First, a magnetoresistive effect element (GMR element) and an inductive element are stacked on a ceramic wafer by a thin film deposition technique and a lithography technique to form a plurality of head elements. Thereafter, the wafers are cut out one by one to form a block (row bar) in which a plurality of head elements are connected. The surface of this row bar that will later become the air bearing surface is polished smoothly while regulating the height of the GMR element. Thereafter, a floating rail is formed on the polished surface by dry etching. Thereafter, the row bar is cut for each head element and divided into thin film magnetic heads. A method of manufacturing such a thin film magnetic head is described in Patent Document 1.

  In the polishing process, the GMR element height is generally controlled based on the output of an ELG (electro lapping guide) sensor. In Patent Document 2, since the resistance of the ELG sensor itself is fluctuated by the surrounding magnetic field and an accurate polishing amount cannot be grasped and correct element height control cannot be performed, the GMR film used in the ELG sensor is sometimes not available. A method of polishing while applying a DC bias magnetic field in the direction in which the pinned layer is pinned is disclosed so that the magnetization direction of the free layer and the magnetization direction of the pinned layer are substantially parallel.

Japanese Patent Laid-Open No. 2002-331452 JP 2003-91804 A

  In order to realize a high recording density, it is necessary to reduce the element size of the recording element and the magnetoresistive effect element and to reduce the size of one bit on the magnetic disk. Therefore, the element size has been reduced year by year in response to the increase in recording density, and in particular, the element size of magnetoresistive effect elements such as GMR elements is on the order of submicrons. However, when the volume of the antiferromagnetic layer of the GMR element is reduced as the element size is reduced, the exchange coupling force that determines the direction of the magnetization direction of the pinned layer is also reduced. Therefore, since the exchange coupling with the pinned layer that determines the magnetization direction becomes weak, the magnetization direction of the pinned layer becomes unstable, and problems caused by this become a serious problem.

  In particular, as the element size becomes narrower, the element height also becomes minute. As explained above, the element height is finished by controlling the dimensions by polishing, so that the pinned layer or antiferromagnetic layer is polished. When the stress due to processing is received and the magnetization direction is locally or totally distorted by the stress and the magnetic characteristics are damaged, the magnetization direction of the pinned layer becomes unstable and the characteristics of the GMR element are deteriorated.

Therefore, although not taken into consideration in the above-described prior art, it is an extremely important issue how to reduce the processing damage that the polishing process gives to the GMR element as the element size is reduced.
An object of the present invention is to provide a method of manufacturing a thin film magnetic head having stable output characteristics even when the element size of the pinned layer of the magnetoresistive effect element can be unstable.

In order to achieve the above object, a method of manufacturing a thin film magnetic head of the present invention includes:
Forming a plurality of magnetoresistive elements having at least a free layer and a pinned layer on the wafer;
Cutting out a row bar in a state where a plurality of magnetoresistive elements are connected from the wafer;
Polishing the surface that becomes the air bearing surface after the row bar while applying an external magnetic field equal to or greater than the coercive force of the pinned layer in the same direction as the magnetization direction of the pinned layer of the magnetoresistive element;
Forming a floating rail on the polished surface;
Cutting the row bar for each magnetoresistive element;
It is characterized by including.
The intensity of the external magnetic field applied to the pinned layer is preferably about 130 kA / m or more.

  According to the present invention, a thin film magnetic head having stable output characteristics can be manufactured even if the element size is such that the magnetic characteristics of the pinned layer of the magnetoresistive effect element can be unstable.

  Before describing a method of manufacturing a thin film magnetic head according to an embodiment of the present invention, a basic configuration of a magnetic disk device and a basic structure of a thin film magnetic head will be described. FIG. 2 is a diagram illustrating the basic configuration of the magnetic disk device, and is a diagram illustrating an outline of a process in which the thin film magnetic head reads the magnetic field of the magnetic disk. The thin film magnetic head 10 has a base material (slider) 11 and a magnetoresistive effect element (GMR element) 12 formed on the rear end surface of the slider 11, and floats on a rotating magnetic disk 13. The magnetic disk 13 holds magnetic information whose recording unit is represented by 1 bit 14, and the GMR element 12 senses and reads a leakage magnetic field 15 from the magnetic information as a signal. The element height 16 of the GMR element 12 greatly affects the sensitivity for detecting the leakage magnetic field 15. The air bearing surface AB of the thin film magnetic head 10 is covered with a protective film 17. The thin film magnetic head 10 is an example of a reproducing head incorporating the GMR element 12, but may be a composite head in which an inductive element is stacked on the GMR element 12.

  An outline of the layer structure of the GMR element 12 incorporated in the thin film magnetic head 10 is shown in FIG. In the layer configuration shown in FIG. 3, the positional relationship between the GMR element 12 and the case seen from the direction of the arrow 27 is the same. Further, the surface AB of the thin film magnetic head 10 shown in FIG. 2 that faces the magnetic disk 13 coincides with the surface AB shown in FIG. The GMR element 12 includes a ferromagnetic layer (free layer) 22, a conductive layer 23, a ferromagnetic layer (pinned layer) 24, and an antiferromagnetic layer 25. A hard bias layer 21 is provided on both sides of the free layer 22. An electrode layer (not shown) is provided on the hard bias layer 21. The magnetization direction 26 d of the free layer 22 is stabilized in the same direction as the magnetization direction 26 c of the hard bias layer 21 and in a direction orthogonal to the leakage magnetic field 15 from the magnetic disk 13. The magnetization direction 26 d of the free layer 22 rotates according to the direction of the leakage magnetic field 15 when the free layer 22 senses the leakage magnetic field 15.

  On the other hand, the magnetization direction 26 b of the pinned layer 24 is fixed in the same direction as the magnetization direction 26 a of the antiferromagnetic layer 25 by exchange coupling generated at the interface with the antiferromagnetic layer 25. Therefore, the magnetization direction 26b of the pinned layer 24 is not changed by the leakage magnetic field 15 from the magnetic disk. The magnetization directions 26 a and 26 b may be parallel to the direction of the leakage magnetic field 15. That is, the directions of the magnetization directions 26a and 26b in FIG. 3 are examples, and both may be reversed. In the normal GMR element 12, the free layer 22 rotates by sensing the leakage magnetic field 15, and the angle formed by the magnetization direction 26 b of the pinned layer 24 and the magnetization direction 26 d of the free layer 22 changes. Information on the magnetic disk can be read as a signal by utilizing the characteristic that the resistance of the GMR element 12 changes due to this change in angle.

FIG. 4 is a flowchart schematically showing a method of manufacturing a thin film magnetic head according to an embodiment of the present invention. In step 41, a free layer 22 and a conductive layer 23 as shown in FIG. 3 are formed on a ceramic wafer made of an AlTiC material (Al ₂ O ₃ —TiC) using a thin film deposition technique such as sputtering and a lithography technique. A pinned layer 24 and an antiferromagnetic layer 25 are stacked, and a hard bias layer 21 and an electrode layer (not shown) are stacked on both sides of the free layer 22 to form a plurality of head elements. The stacking order may be reversed, and the antiferromagnetic layer 25, the pinned layer 24, the conductive layer 23, and the free layer 22 may be stacked in this order. The former is called Top Spin Valve type, and the latter is called Bottom Spin Valve type.

  Thereafter, in a substrate cutting step 42, a block called a row bar in which a plurality of head elements are connected is cut out from the wafer by a cutting technique such as a grinding wheel or a wire saw. In this embodiment, as shown in FIG. 5, the row bar 50 is formed by connecting about 50 head elements, the length L is about 2 inches, and the thickness t is about 0.3 mm. However, this block size is not limited to the above example.

  Next, in step 43, after the row bar 50 is fixed to the polishing jig with wax or the like, the surface that later becomes the air bearing surface (A-B surface in FIG. 2) is pressed against the polishing surface plate while dripping the polishing liquid. Rough polishing.

  Next, in the final air bearing surface polishing step 44, final finishing polishing is performed on the portion of the row bar 50 that will be the air bearing surface of each head element. This final finish polishing is a step of finishing the surface (hereinafter referred to as the air bearing surface) of each head element of the row bar 50 to a predetermined shape with high accuracy and finishing the surface roughness of the air bearing surface to a predetermined value. . The final air bearing surface polishing step 44 will be described in detail later.

  After the final air bearing surface polishing step 44 is finished, in step 45, shallow groove rails 18 and deep grooves 19 (see FIG. 6) are formed on the air bearing surface by dry processing such as ion milling or RIE. Specifically, the row bar 50 is fixed to a rail-forming jig using a thermoplastic adhesive tape, a resist is applied to the surface of the air bearing surface, and after exposure and development, the portions other than the rails are dried. Remove by processing. Thereafter, the resist remaining on the air bearing surface is peeled off. By repeating the process from the resist coating to the resist stripping twice, a floating surface having a two-stage floating rail 20 and a shallow groove rail 18 as shown in FIG. 6 can be formed.

  Finally, in step 46, the row bar 50 is divided by dicing or cutting at the cutting position, thereby completing each thin film magnetic head 10 shown in FIG.

  In the final air bearing surface polishing step 44, polishing is performed in a state where the element height 16 (see FIG. 2) of the GMR element 12 is close to the specification value, so that the exchange coupling between the antiferromagnetic layer 25 and the pinned layer 24 becomes weak, This is a process in which the magnetization direction 26b of the pinned layer 24 is highly likely to become unstable. FIG. 7 shows pin damage caused by polishing. FIG. 7A shows the magnetic moment directions 112 and 111 in the crystals of the antiferromagnetic layer 25 and the pinned layer 24 before polishing, and the directions 26a and 26b of the average magnetic moment of the entire layer. In FIG. 7B, the direction of the magnetic moment of the crystal having a small grain size is changed by the polishing damage in the region 114 near the polishing surface plate of the antiferromagnetic layer 25 and the pinned layer 24, and the average magnetic moment 26A of the entire layer is changed. , 26B are reduced.

  FIG. 8 shows an example in which the distribution of the magnetization direction 26b of the pinned layer 24 changes. FIG. 8A shows a case where the distribution 122 of the magnetization direction after polishing is the same as the distribution 121 of the magnetization direction before polishing, but the intensity is reduced without changing the center of the spin angle. ). In this case, no change is observed in the direction of the sum of the magnetization directions, but since the intensity is small, it is weak against a disturbance factor, and noise is easily generated in the reproduction output. FIG. 8B shows a case where the distribution 123 of the magnetization direction after polishing changes both in the center and intensity of the spin angle. In this case, since the direction of the summation of the magnetization directions changes, the symmetry of the reproduced output waveform is deteriorated. FIG. 8C shows the case where the distribution 124 of the magnetization direction after polishing is rotated by 180 degrees at the center of the spin angle. In this case, since the direction of the sum of the magnetization directions is reversed, the reproduction output is also reversed.

  FIG. 9 shows output characteristics when the direction of the sum of the magnetization directions 26b of the pinned layer 24 is reversed. When the reproduction output of a normal GMR element shows the output characteristic 31, when the exchange coupling strength between the antiferromagnetic layer 25 and the pinned layer 24 becomes weak and the magnetization direction 26b of the pinned layer 24 rotates 180 degrees, the reproduction output is output. It will be inverted like the characteristic 32. For this reason, in the final air bearing surface polishing step 44, as described below, preventing the destabilization of the magnetization direction 26b of the pinned layer 24 is effective in improving the reliability of the magnetic head characteristics.

  10A and 10B schematically show the configuration of a polishing apparatus used in the final air bearing surface polishing step 44 of the above manufacturing method. In the figure, 61 is a swing mechanism, 62 is a polishing liquid, 63 is a work holding jig, 64 is a polishing surface plate, 631 is a swing mechanism mounting portion of the polishing apparatus, and 632 is a magnetic field generating mechanism. The final finish polishing in this embodiment is a polishing method called kiss wrap or touch wrap, and is performed by previously fixing polishing abrasive grains having an average particle size of about 100 nm on a polishing surface plate. Therefore, the polishing liquid 62 dripped during polishing is only lubricating oil, and there are no abrasive grains. The work holding jig 63 includes a magnetic field generating mechanism 632 that can apply a magnetic field to the row bar 50 between the swing mechanism attaching portion 631 and the row bar 50. In this embodiment, a permanent magnet is used as the magnetic field generating mechanism 632.

  Hereinafter, with reference to FIG. 1, the final air bearing surface polishing step 44 of the present embodiment using the polishing apparatus will be described in detail. In step 100, the magnetic field generating mechanism 632 is attached to the swing mechanism attaching portion 631 of the work holding jig 63. Next, in step 102, the row bar 50 is attached to the magnetic field generating mechanism 632 via an adhesive such as an elastic body to reinforce the magnetic moment of the pinned layer 24. That is, the magnetic field generation direction of the magnetic field generation mechanism 632 matches the magnetization direction 26 b of the pinned layer 24.

  Next, in step 104, the work holding jig 63 is mounted on the polishing apparatus, and in step 106, the air bearing surface of the row bar 50 is applied with a predetermined force to the polishing surface plate 64 whose surface has a predetermined shape (planar, spherical or cylindrical). Then, the work holding jig 63 is swung in the radial direction of the surface plate by the rocking mechanism 61 to polish and remove a predetermined processing amount (for example, 50 nm). In the polishing process, the polishing platen 64 is rotated at, for example, 10 r / min while a polishing liquid 62 called diamond-free lubricant 62 is dropped on the polishing platen 64, and the work holding jig 63 swings at 50 mm / s. To do. The row bar 50 is polished by a magnetic field generation mechanism 632 in a state where a magnetic field is applied.

  Next, in step 108, the polishing amount from the start of polishing is measured, and the end point of the polishing process is detected. The polishing amount may be controlled by time, or the processing amount may be controlled by measuring the resistance of the ELG (electro lapping guide) element or the GMR element itself in the row bar 50, but either method may be used. When the predetermined polishing amount is reached, that is, when the end point of the polishing process is detected, the polishing is finished (step 110).

  In addition, if the intensity of the magnetic field applied to the row bar 50 by the magnetic field generation mechanism 632 is equal to or greater than the coercive force of the pinned layer 24, the change in the magnetization direction 26b of the pinned layer 24 can be suppressed. It is desirable that the magnetic field strength of the surface is 1.6 kGs (130 kA / m) or more as measured by a gauss meter.

  Next, with reference to FIG. 11, the relationship between the layer structure of the GMR element 12, the application direction of the magnetic field, and the polishing direction will be described. FIG. 11 shows a case where the GMR element 12 is a single layer type pinned layer 24. The direction seen from the arrow 27 of the layer structure shown in the figure coincides with the direction in which the GMR element 12 is drawn. In the figure, the surface indicated by 64 coincides with the surface for polishing the GMR element 12. The polishing directions are the X direction (rotating direction of the surface plate) and the Y direction (swing direction of the workpiece holding jig). The row bar 50 is held under the magnetic field generation mechanism 632 via an adhesive (not shown) or the like, and the magnetic field direction 26 e generated by the magnetic field generation mechanism 632 is made to coincide with the magnetization direction 26 b of the pinned layer 24. Since the magnetization direction 26b of the pinned layer 24 is determined by the magnetization direction 26a of the antiferromagnetic layer 25, when the magnetization direction 26b of the pinned layer 24 is reversed, the magnetization direction 26e of the magnetic field generating mechanism 632 is also reversed.

  FIG. 12 is a diagram for explaining the effect of the above embodiment. FIG. 12A shows a magnetic moment of the pinned layer 24 by applying a magnetic field of about 130 kA / m in the final air bearing surface polishing step 44 of the above embodiment. The graph shows the relationship between the element height 16 converted from the ELG element resistance obtained by QST (quasistatic tester) measurement and the GMR element output obtained by QST measurement after applying and polishing in the same direction as the sum. In this case, even when the element height 16 is about 40 nm, good output characteristics are shown. On the other hand, FIG. 12B shows the relationship between the converted element height 16 and the element output obtained by QST measurement after polishing without applying a magnetic field to the pinned layer 24. Although the same lot sample as the processing sample used in FIG. 12A is polished, in this case, when the converted processing amount is smaller than about 100 nm, there are some samples in which the output value shows a negative value. The This is presumably because the polarity of the magnetic characteristics of the GMR element 12 has changed due to the change in the magnetization direction 26 b determined by the sum of the magnetization directions of the pinned layer 24. Thus, according to the manufacturing method of the present embodiment, a thin film magnetic head in which the output characteristics of the GMR element are stable and has little variation can be manufactured. Also, as shown in FIG. 12B, when the element height 16 of the GMR element is reduced to about 100 nm, the instability of the magnetization direction 26b of the pinned layer 24 becomes noticeable. For this reason, it is desirable to apply the manufacturing method according to the present embodiment from the time when the element height 16 is larger than 100 nm.

  FIG. 13 is also a diagram for explaining the effect of the above embodiment, and shows the distribution (CDF) of the reproduction output after polishing. The characteristic 151 is when no magnetic field is applied during polishing, the characteristic 152 is when a magnetic field of about 80 kA / m is applied, and the characteristic 153 is according to the above embodiment, and a magnetic field of about 130 kA / m is applied. From this result, when a magnetic field is not applied, even if a magnetic field is applied, there is no effect of suppressing the distribution of reproduction output at about 80 kA / m, and a magnetic field of about 130 kA / m that is greater than the coercivity of the pinned layer 24 is applied. In addition, the effect of suppressing the distribution of the reproduction output appears.

  In the above embodiment, the case where the GMR element 12 is the single layer type pinned layer 24 has been described as an example, but in addition, the pinned layer 24 fixed by the antiferromagnetic layer 25 is a synthetic ferri GMR element, Or even if it is a self-pinned GMR element which does not have an antiferromagnetic layer and maintains the magnetization direction 26b by the pinned layer 24 itself, the same effect can be obtained. When the pinned layer 24 is a synthetic ferrimagnetic GMR element, the pinned layer 24 has a sandwich structure of two pinned layers through an intermediate layer such as ruthenium, but is determined by the sum of the magnetic moments of the pinned layer 24. The external magnetic field is adjusted to the magnetization direction.

  Moreover, in the said Example, although the permanent magnet was used for the magnetic field generation mechanism 632, what can generate | occur | produce a magnetic field, such as an electromagnet, can be used, In that case, the same effect as the said Example can be acquired. For example, as shown in FIG. 14, a circuit for supplying a pulse current to the conductive layer 23 of the GMR element is provided, and the induced magnetic field 26f generated in the conductive layer 23 by the pulse current is directed in the same direction as the magnetization direction 26b of the pinned layer 24. Even if it polishes, it can suppress that the magnetization direction 26b of the pinned layer 24 rotates during grinding | polishing.

  In the above embodiment, the effect was demonstrated using the GMR element. However, even if the magnetoresistive element is a TMR (tunnel barrier MR) element or a CPP type GMR element, the configuration of the pinned layer 24 is basically the same. Since they are the same, it is needless to say that the magnetization direction can be stabilized as in the above embodiment.

  As described above in detail, according to the above-described embodiment, the air bearing surface of the thin film magnetic head is applied with an external magnetic field applied in a direction in which the magnetization direction of the pinned layer of the magnetoresistive element on the row bar or slider is stabilized. Polishing. Thus, a thin film magnetic head having stable magnetic characteristics can be manufactured by stabilizing the magnetization direction of the pinned layer during polishing. As a result, it is possible to manufacture a thin film magnetic head with high yield and high reliability.

  All the embodiments described above are illustrative of the present invention and are not intended to be limiting. For example, after polishing, the magnetoresistive effect such as applying a pulse current to the magnetoresistive effect element or the recording element for the purpose of magnetic stabilization of the magnetoresistive effect element to alleviate the distortion that hinders the magnetic characteristics of the magnetic head. There is a method to improve the characteristics of the element, but this is not in conflict with the method of manufacturing the thin film magnetic head according to the present invention. By using it in combination, the output characteristics of the magnetoresistive effect element are more stable and less variable. It goes without saying that the head can be manufactured.

It is a flowchart which shows the detailed process of the last air bearing surface grinding | polishing process of FIG. 1 is a schematic diagram showing a basic configuration of a magnetic disk device. It is the schematic which shows the laminated structure of a magnetoresistive effect element (GMR element). 4 is a flowchart of a method of manufacturing a thin film magnetic head according to an embodiment of the present invention. It is a perspective view of a rover. It is a perspective view which shows the air bearing surface shape of a thin film magnetic head. It is a schematic diagram which shows the mode of the pin damage by grinding | polishing. It is a figure which shows distribution of the magnetization direction of the pinned layer by the damage of grinding | polishing. It is a figure which shows the output characteristic of a GMR element. It is a perspective view which shows schematic structure of the grinding | polishing apparatus used at the last air bearing surface grinding | polishing process of FIG. It is a figure which shows the relationship between the layer structure of a GMR element, the application direction of a magnetic field, and a grinding | polishing direction. It is a figure which shows the relationship between the element height after final finish grinding | polishing, and a reproduction output. It is a figure which shows distribution (CDF) of the reproduction output after final finish grinding | polishing. It is a figure which shows the other example of a magnetic field generation means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Thin film magnetic head, 11 ... Floating rail, 12 ... Magnetoresistive effect element (GMR element),
DESCRIPTION OF SYMBOLS 13 ... Magnetic disk, 14 ... Recording unit (1 bit), 15 ... Leakage magnetic field, 16 ... Element height, 17 ... Protective film, 18 ... Shallow groove rail, 19 ... Deep groove, 20 ... Floating rail, 21 ... Hard bias layer , 22 ... free layer, 23 ... conductive layer, 24 ... pinned layer, 25 ... antiferromagnetic layer, 26a ... magnetization direction of antiferromagnetic layer, 26b ... magnetization direction of pinned layer, 26c bias magnetization direction, 26d ... free layer 26e, 26f ... Magnetic field application direction, 31, 32 ... Output characteristics, 50 ... Rover, 61 ... Oscillating mechanism, 62 ... Polishing liquid, 63 ... Work holding jig, 64 ... Polishing surface plate, 111, DESCRIPTION OF SYMBOLS 112 ... Magnetic moment, 114 ... Polishing damage area | region, 153 ... Distribution of reproduction | regeneration output, 631 ... Swing mechanism attachment part of a polishing apparatus, 632 ... Magnetic field generation mechanism.

Claims (13)

Forming a plurality of magnetoresistive elements having at least a free layer and a pinned layer on the wafer;
Cutting out a row bar in a state where a plurality of magnetoresistive elements are connected from the wafer;
Polishing the surface of the row bar that later becomes the air bearing surface while applying an external magnetic field equal to or greater than the coercive force of the pinned layer in the same direction as the magnetization direction of the pinned layer of the magnetoresistive element;
Forming a floating rail on the polished surface;
Cutting the row bar for each magnetoresistive element;
A method of manufacturing a thin film magnetic head, comprising:   2. The method of manufacturing a thin film magnetic head according to claim 1, wherein the intensity of the external magnetic field applied to the pinned layer is about 130 kA / m or more.   2. The thin film magnetic head according to claim 1, wherein when the pinned layer is a single layer type, the polishing is performed while applying an external magnetic field in the same direction as the magnetization direction of the single layer type pinned layer in the polishing step. Method.   2. The thin film magnetic head according to claim 1, wherein when the pinned layer is of a synthetic ferri type, the polishing is performed while applying an external magnetic field in the same direction as the sum of the magnetic moments of the synthetic ferri type pinned layer in the polishing step. Manufacturing method.   2. The method of manufacturing a thin film magnetic head according to claim 1, wherein when the pinned layer is a self-pinned type, polishing is performed while applying an external magnetic field in the same direction as the magnetization direction of the self-pinned pinned layer in the polishing step.   The magnetoresistive element has an antiferromagnetic layer adjacent to the pinned layer, and the magnetization direction of the pinned layer is the magnetization direction of the antiferromagnetic layer by an exchange coupling magnetic field generated at the interface with the antiferromagnetic layer. 2. A method of manufacturing a thin film magnetic head according to claim 1, wherein the thin film magnetic head is fixed to the head.   2. The method of manufacturing a thin film magnetic head according to claim 1, wherein in the step of forming the magnetoresistive effect element on the wafer, an inductive magnetic conversion element is further formed adjacent to the magnetoresistive effect element. Forming a plurality of magnetoresistive elements having at least a free layer and a pinned layer on the wafer;
Cutting out a row bar in a state where a plurality of magnetoresistive elements are connected from the wafer;
The row bar is attached to a magnetic field generating mechanism mounted on a holding jig, and the magnetic field generating mechanism applies a magnetic field greater than the coercive force of the pinned layer in the same direction as the magnetization direction of the pinned layer of the magnetoresistive effect element. Pressing the surface of the row bar that will later become the air bearing surface against a polishing platen, rotating the polishing platen, and swinging the holding jig in the radial direction of the polishing platen for polishing;
Forming a floating rail on the polished surface;
Cutting the row bar for each magnetoresistive element;
A method of manufacturing a thin film magnetic head, comprising:   9. The method of manufacturing a thin film magnetic head according to claim 8, wherein the intensity of the magnetic field applied to the pinned layer by the magnetic field generation mechanism is about 130 kA / m or more.   9. The method of manufacturing a thin film magnetic head according to claim 8, wherein the magnetic field generating mechanism is a permanent magnet.   9. The method of manufacturing a thin film magnetic head according to claim 8, wherein the magnetic field generating mechanism is an electromagnet.   The magnetic field generation mechanism includes a conductive layer of the magnetoresistive effect element and a circuit that applies a pulse current to the conductive layer, and applies an induced magnetic field generated in the conductive layer to the pinned layer. Item 9. A method of manufacturing a thin film magnetic head according to Item 8.   9. The method of manufacturing a thin film magnetic head according to claim 8, wherein in the step of forming the magnetoresistive effect element on the wafer, an inductive magnetic conversion element is further formed adjacent to the magnetoresistive effect element.

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