JP2007311400A - Process for fabricating magnetoresistive effect element with bias layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for fabricating an MR effect element in which inclination or dispersion of a magnetization fixation layer occurred during fabrication process is eliminated finally, and magnetization of the magnetization fixation layer is fixed appropriately while applying an appropriate bias magnetic field to a bias layer. <P>SOLUTION: The fabrication process of an MR effect element comprises an MR effect laminate including an antiferromagnetic layer, a magnetization fixation layer where magnetization is fixed in the first direction in the lamination plane, a nonmagnetic intermediate layer, and a magnetization free layer; and a bias layer for applying a bias magnetic field in the second direction in the lamination plane intersecting the first direction perpendicularly to the magnetization free layer. The MR effect laminate and the bias layer thus formed are subjected to first magnetic field application processing for applying a first magnetic field larger than the coercive force of the bias layer in the first direction, and then subjected to second magnetic field application processing for applying a second magnetic field larger than the coercive force of the bias layer in the second direction following to annealing for applying heat. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetoresistive (MR) effect element having a bias layer for applying a bias magnetic field to a magnetization free layer, and more particularly to a magnetic disk device or the like having such an MR effect element for reading data. The present invention relates to a method of manufacturing a thin film magnetic head used.

  As the hard disk drive has a large capacity and a small size, a thin film magnetic head with high sensitivity and high output is required. In order to meet this demand, characteristics of a GMR head using a giant magnetoresistive (GMR) effect element for reading data are being improved. On the other hand, a tunnel magnetoresistive (TMR) effect element that can be expected to have a resistance change rate more than twice the GMR effect has been attracting attention in order to cope with further higher recording density. At present, the development of a TMR head that uses this TMR effect element for data reading has been energetically performed.

  Both the MR effect element such as the TMR effect element and the GMR effect element include a magnetization fixed layer and a magnetization free layer which are two ferromagnetic layers opposed to each other with a nonmagnetic layer interposed therebetween. The magnetization direction of the magnetization fixed layer is fixed by exchange coupling with the antiferromagnetic layer that is in contact with the magnetization fixed layer. On the other hand, the magnetization direction of the magnetization free layer changes corresponding to the signal magnetic field from the recording medium. In such a configuration, the signal magnetic field is detected by measuring an element resistance value that changes as a function of the magnetization direction.

  Therefore, when improving element output characteristics such as output intensity and SN ratio in these MR effect elements, it is one of the most important issues to appropriately control the magnetization directions of these layers constituting the element.

  For example, the magnetization direction of the above-described magnetization fixed layer is generally fixed in a direction perpendicular to the track width direction within the laminated surface by pin annealing. At this time, if the magnetization is not correctly oriented in the vertical direction or is dispersed, sufficient element output cannot be obtained, or a lot of noise is generated during output, resulting in deterioration of output intensity or SN ratio. Problems can arise. Therefore, as described in, for example, Patent Document 1, various devices have been conventionally made regarding the pin annealing treatment.

  In these MR effect elements, it is important to apply an appropriate bias magnetic field to the magnetization free layer, stabilize the magnetic domain of the magnetization free layer, and obtain an output that linearly responds to the signal magnetic field from the magnetic disk. Become. Here, if the bias magnetic field is weak, the magnetic domain of the magnetization free layer is not stable, so noise such as Barkhausen noise is generated and the output intensity and SN ratio are deteriorated. On the other hand, if the bias magnetic field is too strong, the magnetization of the magnetization free layer becomes difficult to move, and thus a reduction in output is inevitable. Therefore, in order to achieve both linear response and high output by stabilizing the magnetic domain, it is important how to provide an appropriate bias magnetic field.

  A general method for applying this bias magnetic field is an abutted junction (AJ) bias method. In this method, a bias layer made of a hard magnetic material is disposed in the vicinity of both ends in the track width direction of the magnetization free layer, and a bias magnetic field in the track width direction is applied to the magnetization free layer. In this AJ bias method, the strongest bias magnetic field is applied to both ends in the track width direction of the magnetization free layer that is most susceptible to the demagnetizing field, so that the magnetic domain of the magnetization free layer can be stabilized efficiently.

  Further, in the manufacturing process of the thin film magnetic head, not only the wafer thin film process on the wafer substrate but also various heat treatment processes performed in the machining process from the wafer substrate to the individual slider are separated into each layer constituting the element. It has been found that this has a strong influence on the state of the magnetization direction, that is, the head output characteristics. For example, in Patent Document 2, a predetermined heat treatment is performed after cutting a processing bar from a wafer substrate to prevent deformation of the magnetic head during the process of processing as a slider. Further, in Patent Document 3, heat treatment is performed after polishing for height processing to eliminate processing alteration that has occurred in the MR effect element.

JP 2005-56538 A JP-A-11-316927 JP 2004-206846 A

  However, even if a predetermined pin annealing treatment is performed to fix the magnetization direction of the magnetization fixed layer, there is a problem that noise during output can be increased by the subsequent heat treatment.

  In particular, with the recent increase in recording density, the MR effect element itself tends to be further thinned, and it is very important to release the processing distortion that is added to the element in the machining process and causes noise. It has become. As a countermeasure against this, as described in Patent Documents 2 and 3, it is possible to remove the processing strain by heat treatment. It has been found to increase.

  The inventors of the present application investigated the cause of this noise, and in a head in which an increase in noise was observed, the head was subjected to a strong influence such as tilting or dispersion of the magnetization of the magnetization fixed layer during the head manufacturing process. It was found that the effect became obvious after the annealing treatment to release the processing strain. At this time, since the magnetization of the magnetization fixed layer receives a magnetic field from the bias layer during various heat treatments, it is considered that the influence of this magnetic field is very large.

  Therefore, the object of the present invention is to finally eliminate the magnetization inclination or dispersion of the magnetization fixed layer that occurs during the manufacturing process, and to appropriately fix the magnetization of the magnetization fixed layer while applying an appropriate bias magnetic field to the bias layer. Another object of the present invention is to provide a method for manufacturing an MR effect element, and a method for manufacturing a thin film magnetic head including such an MR effect element.

  Before describing the present invention, the terms used in the specification are defined. In the laminated structure of magnetic head elements formed on the element formation surface of the substrate, the component on the substrate side with respect to the reference layer is assumed to be “below” or “below” the reference layer, which becomes the reference It is assumed that the component on the side in the direction of stacking from the layer is “above” or “above” the reference layer.

According to the present invention, the antiferromagnetic layer is exchange-coupled to the antiferromagnetic layer, and the magnetization is fixed in a predetermined direction (so-called pin direction, hereinafter referred to as the first direction) in the laminated surface. MR effect laminate comprising: a fixed magnetization layer; a magnetization free layer whose magnetization direction changes according to a magnetic field from outside; and a nonmagnetic intermediate layer provided between the magnetization fixed layer and the magnetization free layer When,
An MR comprising a bias layer that is located near the end of the magnetization free layer and that applies a bias magnetic field in the second direction in the stack plane perpendicular to the first direction to the magnetization free layer A method for producing an effect element, comprising:
A first magnetic field application process for applying a first magnetic field larger than the coercive force of the bias layer in the first direction was performed on the formed MR effect laminate and the bias layer, and an annealing process for applying heat was performed. Thereafter, a method of manufacturing an MR effect element is provided that performs a second magnetic field application process in which a second magnetic field larger than the coercive force of the bias layer is applied in a second direction.

  In such a method of manufacturing an MR effect element according to the present invention, the magnetization of the bias layer “breaks down” in the first direction due to the execution of the first magnetic field application process, or the first magnetic field is applied, for example. In the case of an AC demagnetizing magnetic field, the bias layer is demagnetized. Here, as for the magnetization of the magnetization fixed layer, even after the application of the first magnetic field is finished, the bias magnetic field continues to receive the bias magnetic field in the first magnetic field direction due to the magnetization of the bias layer, or the bias layer is demagnetized. Is released from the bias magnetic field in the second direction. Next, in this state, when an annealing process such as releasing the processing strain is performed, the effect of aligning the magnetization by the bias magnetic field in the first direction or the effect of being released from the bias magnetic field in the second direction The inclination or dispersion of the magnetization originally possessed by the magnetization fixed layer can be suppressed by heat treatment or the like up to that point.

  Next, the magnetization of the bias layer is re-magnetized in the second direction by performing the second magnetic field application process. As a result, a bias magnetic field in the track width direction is applied again to the magnetization free layer. Here, the magnetization of the magnetization fixed layer is maintained while being fixed in the first direction in a state in which inclination or dispersion is suppressed. Therefore, by using the manufacturing method according to the present invention described above, the bias layer applies an appropriate bias magnetic field after finally eliminating the magnetization inclination or dispersion of the magnetization fixed layer generated during the manufacturing process. Furthermore, a state in which the magnetization of the magnetization fixed layer is appropriately fixed is realized.

  In the MR effect element manufacturing method according to the present invention described above, before the first magnetic field application process, the annealing process, and the second magnetic field application process are performed, the magnetization fixed process of the magnetization fixed layer and the bias layer are performed. It is also preferable to perform the magnetizing process. That is, after or during the formation of the antiferromagnetic layer and the magnetization fixed layer, a magnetic field is applied in the first direction while heating to fix the magnetization direction of the magnetization fixed layer in the first direction, and After or during the formation of the magnetization free layer and the bias layer, a magnetic field is applied in the second direction to magnetize the bias layer in the second direction, and then the first magnetic field application treatment, annealing treatment, It is also preferable to perform the magnetic field application process of No. 2.

  That is, after the magnetization pinning process of the magnetization pinned layer and the magnetization process of the bias layer are performed one after another, the first magnetic field application process, the annealing process, and the second magnetic field application process are performed, thereby It becomes possible to finally cancel the inclination or dispersion of the magnetization.

  Moreover, it is preferable that the nonmagnetic intermediate layer of the MR effect element according to the present invention is a tunnel barrier layer having electrical insulation, and the MR effect element is a TMR effect element. Furthermore, it is preferable that the bias layer of the MR effect element according to the present invention is provided in the vicinity of both ends of the magnetization free layer in the second direction.

  In the above-described method for manufacturing an MR effect element according to the present invention, the annealing temperature of the annealing treatment is preferably 160 ° C. or higher and 220 ° C. or lower. Annealing treatment in this temperature range ensures improvement of system and head noise, particularly improvement of low frequency components. Further, the first magnetic field is preferably a static magnetic field having a constant strength, or is preferably an AC demagnetizing magnetic field with gradually decreasing amplitude.

  According to the present invention, there is further provided a method for manufacturing a thin film magnetic head including an MR effect element for reading data, in which an MR effect element is manufactured by the manufacturing method described above. In the method of manufacturing a thin film magnetic head according to the present invention, it is preferable that the first direction, that is, the pin direction is a direction perpendicular to the track width direction, and the second direction is the track width direction. .

  In the method of manufacturing the thin film magnetic head according to the present invention described above, a magnetic head element having a magnetoresistive effect element is formed on the element forming surface of the substrate, and the magnetic head is formed from the substrate on which the magnetic head element is formed. It is preferable to cut out a processing bar in which elements are arranged in a line, and thereafter, perform a first magnetic field application process, an annealing process, and a second magnetic field application process on the processing bar. At this time, it is more preferable to perform an annealing process on the processing bar after the rough polishing for the height processing for determining the position of the air bearing surface and the MR height and before the fine polishing.

  Furthermore, in the method of manufacturing the thin film magnetic head according to the present invention described above, after the processing bar cut out from the substrate is cut and separated into the slider, the second magnetic field application process is performed on the separated slider. You may implement.

  According to the manufacturing method of the MR effect element or the thin film magnetic head according to the present invention, the magnetization inclination or dispersion of the magnetization fixed layer generated during the manufacturing process is finally eliminated, and an appropriate bias magnetic field is applied to the bias layer. The magnetization of the magnetization fixed layer can be appropriately fixed. Thereby, an output characteristic in which noise is suppressed is realized.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated in detail, referring an accompanying drawing. In the drawings, the same elements are denoted by the same reference numerals. In addition, the dimensional ratios in the components in the drawings and between the components are arbitrary for easy viewing of the drawings.

  FIG. 1 is a cross-sectional view schematically showing a layer structure of an MR effect element according to the manufacturing method of the present invention. Here, the cross-section in the figure is a plane parallel to the head end face facing the recording medium.

  In FIG. 1, an MR effect element 10 includes an MR effect laminate 11, a bias layer 17 provided near both ends in the track width direction of the MR effect laminate 11 via a nonmagnetic insulating layer 16, and the MR effect laminate. An underlayer 13 and a cap layer 14 provided in contact with the upper and lower surfaces of the body 11, and a lower electrode layer 12 and an upper electrode provided so as to sandwich the underlayer 13, the MR effect laminate 11 and the cap layer 14. Layer 15.

  The foundation layer 13 includes first and second foundation films 13 a and 13 b, is provided on the lower electrode layer 12, and electrically connects the MR effect laminate 11 to the lower electrode layer 12. Further, the cap layer 14 is provided with the upper electrode layer 15 thereon, thereby electrically connecting the MR effect laminate 11 to the upper electrode layer 15. Therefore, the sense current at the time of magnetic field detection flows in a direction perpendicular to each layer surface in the MR effect multilayer 11 between the upper and lower electrode layers. The underlayer 13 may consist of a single underlayer.

  The MR effect laminate 11 in the present embodiment is a TMR effect laminate having a configuration for producing the TMR effect. Reference numeral 100 denotes an antiferromagnetic layer, 101 denotes a magnetization fixed layer, 102 denotes a tunnel barrier layer as a nonmagnetic intermediate layer, and 103 denotes a magnetization free layer.

  The magnetization fixed layer 101 is provided on the antiferromagnetic layer 100 made of an antiferromagnetic material, and a first ferromagnetic film 101a, a nonmagnetic film 101b, and a second ferromagnetic film 101c are sequentially formed. It has a stacked so-called synthetic ferri structure. An exchange bias magnetic field is applied to the first ferromagnetic film 101a by exchange coupling with the antiferromagnetic layer 100, so that the magnetization direction of the entire magnetization fixed layer 101 is stably fixed.

  The magnetization free layer 103 laminated on the tunnel barrier layer 102 has a configuration in which a high polarizability film 103a and a soft magnetic film 103b are sequentially provided and stacked from the tunnel barrier layer 102 side. The magnetization free layer 103 changes the magnetization direction in response to an applied signal magnetic field. On the other hand, it forms a ferromagnetic tunnel coupling with the magnetization fixed layer 101 using the tunnel barrier layer as a barrier for the tunnel effect. ing. Therefore, when the magnetization direction of the magnetization free layer 103 changes in response to the signal magnetic field, the tunnel current increases or decreases due to fluctuations in the state density of the up and down spin bands of the magnetization free layer 103, and as a result, the electrical current of the MR effect stack 11 is increased. The resistance value changes. By measuring this amount of change, a weak and local signal magnetic field can be reliably detected with high sensitivity. Here, the high polarizability film 103a is not necessarily required and can be omitted. If omitted, a resistance change rate equivalent to the soft magnetic film 103b existing at the interface with the tunnel barrier layer 102 is realized.

  The bias layer 17 is made of a ferromagnetic material and applies a bias magnetic field to the magnetization free layer 103 via the thin nonmagnetic insulating layer 16 to promote stabilization of the magnetic domain of the magnetization free layer 103.

  Note that the mode of each film constituting the magnetization fixed layer 101, the tunnel barrier layer 102, and the magnetization free layer 103 is not limited to those described above. For example, in the magnetization fixed layer 101, in addition to the three-layer structure, a single-layer structure made of a ferromagnetic film or a multi-layer structure having another number of layers can be adopted. Further, in the magnetization free layer 103, in addition to the two-layer structure, a single-layer structure without a high polarizability film or a multilayer structure of three or more layers including a magnetostriction adjusting film can be adopted. Furthermore, the antiferromagnetic layer, the magnetization fixed layer, the tunnel barrier layer, and the magnetization free layer may be laminated in the reverse order, that is, the magnetization free layer, the tunnel barrier layer, the magnetization fixed layer, and the antiferromagnetic layer. .

  FIG. 2 is a flowchart schematically showing one embodiment of a method of manufacturing a thin film magnetic head according to the present invention.

  According to FIG. 2, first, the lower electrode layer 12 is formed on the element forming surface of the slider wafer substrate (step 1). Next, the MR effect laminate 11 is formed (step 2). Thereafter, a pin annealing process is performed to fix the magnetization direction of the magnetization fixed layer 101 in a first direction (a direction perpendicular to the paper surface of FIG. 1) in the stacked surface and perpendicular to the track width direction (step) 3). The pin annealing treatment is performed, for example, by raising the temperature to 250 to 300 ° C. while applying a magnetic field of about 8 kOe (about 640 kA / m) in the first direction, and then lowering the temperature. When the temperature falls below the blocking temperature of the antiferromagnetic layer 100, the magnetization of the magnetization fixed layer 101 is fixed in the first direction.

  Next, a nonmagnetic insulating layer 16 and a bias layer 17 are formed (step 4), and an upper electrode layer is further formed (step 5). Thereafter, a magnetization process is performed to direct the magnetization of the bias layer 17 in the second direction, which is the track width direction, and to apply a bias magnetic field in the second direction to the magnetization free layer 103 (step 6). This magnetization process is performed by applying a magnetic field of about 10 kOe (about 800 kA / m) in the second direction at room temperature. As described above, the formation of the MR effect element for reading data is completed in steps 1 to 6.

  Next, a backing coil portion is formed (step S7). Here, as will be described later, the backing coil portion is a constituent element of a thin film magnetic head for perpendicular magnetic recording, and generates a magnetic flux that is generated from the electromagnetic coil element and cancels the magnetic flux loop passing through the MR effect element. This is intended to suppress the wide area adjacent track erasure (W-ATE) phenomenon. Therefore, it may be omitted when manufacturing a thin film magnetic head for longitudinal magnetic recording. Thereafter, an electromagnetic coil element for writing data is formed (step S8).

  Here, in the backing coil portion and the electromagnetic coil element, as will be described later, a coil insulating layer made of a resist is formed for insulating the coil layer, but after this formation, for thermosetting the coil insulating layer, Heat treatment at about 200 to 300 ° C. is performed. During this heat treatment, the magnetization fixed layer 101 is heated in a state where a bias magnetic field is applied in a second direction orthogonal to the first direction in which the magnetization is directed. May occur.

  Next, a covering layer and a signal terminal electrode are formed (step S9). Thus, the wafer thin film process for forming the magnetic head element including the MR effect element and the electromagnetic coil element on the wafer substrate is completed.

  Next, the wafer substrate after the wafer thin film process is cut, and a processing bar in which a plurality of magnetic head elements are arranged in a row is cut out (step S10). Next, this processing bar is subjected to rough polishing as height processing for determining the position of the air bearing surface (ABS) and the MR height (MR height) of the MR effect element, that is, the length in the direction perpendicular to the ABS ( Step 11).

Thereafter, the first to be applied to machining bars this rough polishing is applied, the first magnetic field is a large magnetic field than the coercive force H _C of the ferromagnetic material constituting the bias layer 17, a first direction The magnetic field application process is performed (step 12). Here, the first magnetic field is, for example, about 6 kOe (480 kA / m). As a result, the magnetization of the bias layer 17 is directed in the first direction perpendicular to the track width direction, and the magnetization of the magnetization free layer 103 is also directed in the first direction. At this time, the bias magnetic field that has been applied to the magnetization fixed layer 101 disappears in the component in the track width direction (second direction).

Incidentally, as the first magnetic field, initially, it may be used degaussing magnetic field alternating gradually attenuates has a large magnetic field amplitude than the coercive force H _C of the bias layer 17.

  Next, after the first magnetic field application process is finished, an annealing process is performed in which heat is applied to the machining bar on which the process has been performed to release machining distortion caused by machining (step 13). The annealing temperature at this time is preferably 160 ° C. or higher and 220 ° C. or lower.

Then, the processing bar this annealing process is performed, the second magnetic field is large magnetic field than the coercive force H _C of the ferromagnetic material constituting the bias layer 17, a second magnetic field applied in a second direction An application process is performed (step 14). Here, this process is preferably performed at room temperature, and the second magnetic field is set to about 6 kOe (480 kA / m), for example. As a result, the bias layer 17 is again magnetized in the track width direction (second direction).

  Next, fine finishing is performed on the formed ABS (step 15). Further, a protective film for protecting the end of the magnetic head element is formed on the head end surface on the ABS side (step 16). Next, processing for forming rails on the ABS is performed (step 17), and then the processing bar is cut and separated into individual sliders (step 18). Thus, the machining process for forming the slider is completed, and the manufacturing process of the thin film magnetic head is completed.

  Note that the first magnetic field application process may be performed after the MR effect element is formed and before the MR height processing, without being performed at the position of step 12. That is, the first magnetic field application process can be performed at any stage as long as it is after the formation of the MR effect element and before the annealing process of step 13. Further, the re-magnetization process of the bias layer 17 by the application of the second magnetic field, that is, the second magnetic field application process is not performed at the position of step 14 until the end of manufacturing after the separation of the slider (step 18). It is possible to implement during

  Furthermore, the protective film formation step (step 16) is performed without performing the second magnetic field application processing at the position of step 14, and then the annealing treatment (step 13) similar to step 13 is performed to further release the processing strain. Step 13 ') may be further performed. In this case, the second magnetic field application process (step 14 ') is performed thereafter.

  Furthermore, the slider separation (step 18) is performed without performing the second magnetic field application process at the position of step 14, and then the annealing process similar to step 13 is performed to further release the processing strain. (Step 13 '') may be further performed. In this case, the second magnetic field application process (step 14 ″) is performed thereafter.

  Here, it has been experimentally confirmed that the system and head noise can be improved at an annealing temperature of 160 ° C. or higher for the annealing temperature for releasing the processing strain described above. In general, when the annealing temperature for the magnetic head element exceeds 300 ° C., crystal grain growth of the NiFe-based soft magnetic film, which is a component of the MR effect element, is promoted, and the coercive force is rapidly increased to increase the element sensitivity. Is well known to decrease. Therefore, this annealing temperature is preferably 160 ° C. or higher and 300 ° C. or lower. Furthermore, the annealing temperature is desirably set to 220 ° C. or lower from the viewpoint of improving the system and head noise, particularly low frequency components, and is more preferably 160 ° C. or higher and 220 ° C. or lower.

  Furthermore, it is preferable that the annealing time of the annealing treatment is a time until the processing strain that exists at the stage of the annealing treatment and causes head noise is removed. In fact, in the actual manufacturing process, the annealing temperature determines the magnitude of the effect. Although the desired annealing effect can be obtained by performing the annealing process for a very long time, it is contrary to the demand for shortening the manufacturing period. Actually, this annealing time is, for example, about 1 hour.

  Next, the effects of the first magnetic field application process, the annealing process, and the second magnetic field application process described above will be described.

  FIG. 3 is a schematic view for explaining the operation and effect of one embodiment of the method of manufacturing a thin film magnetic head according to the present invention.

  FIG. 3A shows the magnetization state of the MR effect element before the first magnetic field application process is performed. In the figure, the magnetization 30 of the magnetization fixed layer 101 is fixed in a first direction that is perpendicular to the track width direction in the stacking plane. On the other hand, the bias layer 17 is magnetized with the magnetization 32 directed in the second direction, which is also in the stack plane but in the track width direction. A bias magnetic field 33 generated by the magnetization 32 is exerted on the magnetization free layer 103. Here, the magnetization 30 of the magnetization fixed layer 101 is slightly inclined or dispersed from the first direction due to the influence of the bias magnetic field 33 during the manufacturing process. This inclination or dispersion of the magnetization 30 causes noise during head output.

  As shown in FIG. 3B, the first magnetic field 34 in the first direction is applied to the MR effect element in such a magnetized state. By this first magnetic field application process, the magnetization 32 of the bias layer 17 “breaks down” and faces in the first direction. At this time, the magnetization 30 of the magnetization fixed layer 101 has a bias in the first magnetic field direction because the magnetization 32 of the bias layer 17 faces the first direction even after the application of the first magnetic field 34 is finished. Continue to receive the magnetic field 35. Next, when an annealing process for releasing the processing strain is performed in this state, the inclination or dispersion of the magnetization 30 is suppressed to be small due to the effect of aligning the magnetization by the bias magnetic field 35.

  Next, as shown in FIG. 3C, a second magnetic field 36 in the second direction is applied to the MR effect element that has returned to room temperature. By this second magnetic field application process, the magnetization 32 of the bias layer 17 is remagnetized in the second direction. As a result, the bias magnetic field 37 in the track width direction is applied to the magnetization free layer 103 again. Here, since the second magnetic field application process is a process at room temperature, the magnetization 30 of the magnetization fixed layer 101 is maintained while being fixed in the first direction in a state where inclination or dispersion is suppressed. .

  The bias layer 17 applies an appropriate bias magnetic field 37 after the inclination or dispersion of the magnetization of the magnetization fixed layer 101 generated during the manufacturing process is finally eliminated by the processing according to the present invention described above. Further, a state in which the magnetization 30 of the magnetization fixed layer 101 is appropriately fixed is realized. As a result, output characteristics in which noise is suppressed can be obtained.

  FIG. 4 is a schematic view for explaining the operation and effect of another embodiment of the method of manufacturing a thin film magnetic head according to the present invention.

  FIG. 4 shows a magnetization state when an AC demagnetizing magnetic field 40 whose amplitude gradually attenuates is applied as the first magnetic field. Here, the magnetization state of the MR effect element before applying the decaying AC magnetic field 40 is the same as in FIG.

That is, according to the figure, a first magnetic field application process, the initial amplitude is large demagnetizing field 40 than the coercive force H _C of the bias layer 17 is applied to the first direction, the magnetization of the bias layer 17 Becomes zero and the bias layer 17 is demagnetized. At this time, the magnetization 30 of the magnetization fixed layer 101 is maintained in the first direction. Subsequently, when annealing is performed thereafter, the inclination or the degree of dispersion is reduced by the effect of being released from the bias magnetic field in the second direction. Thereafter, by performing the second magnetic field application process, the magnetization of the bias layer 17 is remagnetized in the second direction, and a magnetization state similar to that in FIG. 3C is realized.

  Also by the process according to the other embodiment of the present invention described above, the bias layer 17 is appropriately biased magnetic field 37 after the inclination or dispersion of the magnetization of the magnetization fixed layer 101 generated during the manufacturing process is finally eliminated. Further, a state in which the magnetization 30 of the magnetization fixed layer 101 is appropriately fixed is realized. As a result, an output characteristic in which noise is suppressed to be small can be obtained.

  FIG. 5 is a sectional view showing an embodiment of a wafer thin film process in the method of manufacturing a thin film magnetic head according to the present invention. In addition, the cross section in the same figure is a surface perpendicular | vertical to an element formation surface and ABS.

Hereinafter, the wafer thin film process of the thin film magnetic head will be described with reference to FIG. First, as shown in FIG. 5A, on a wafer substrate 50 formed of, for example, AlTiC (Al ₂ O ₃ —TiC) or the like, a thickness 0 made of, for example, Al ₂ O ₃ or the like is formed by, eg, sputtering. A base insulating layer 51 of about 0.05 to 10 μm is laminated. Next, a lower electrode layer (lower shield layer) having a thickness of about 0.3 to 3 μm made of, for example, NiFe, NiFeCo, CoFe, FeN, or FeZrN is formed on the base insulating layer 51 by, for example, frame plating or sputtering. 12 is formed.

  Next, the base layer 13, the MR effect laminate 11, the cap layer 14, and the bias layer 17 (not shown in FIG. 5) are formed by using, for example, a sputtering method, a photolithography method, an ion beam etching method, or the like. The MR effect laminate 11 may be the TMR effect laminate described with reference to FIG. 1, or a perpendicular conduction type giant magnetoresistance (CPP (current perpendicular to plain) -GMR) effect laminate. Good. Furthermore, an in-plane energization type giant magnetoresistance (CIP (current in plain) -GMR) effect laminate may be used. In either case, the signal magnetic field from the magnetic disk is sensed with very high sensitivity and reading is performed.

  A method for manufacturing the MR effect element 10 including the formation of the underlayer 13, the MR effect laminate 11, the cap layer 14, and the bias layer 17 will be described in detail with reference to FIG.

Next, a thickness of 0.3 to 4 μm made of, for example, NiFe, NiFeCo, CoFe, FeN, or FeZrN so as to sandwich the MR effect laminate 11 with the lower electrode layer 12 by, for example, frame plating or sputtering. An upper electrode layer (upper shield layer) 15 is formed to a certain extent. Next, the bias layer 17 is magnetized (step 6 in FIG. 2), and the formation of the MR effect element 10 is completed. Next, the first nonmagnetic layer 53 made of, for example, Al ₂ O ₃ or the like and having a thickness of about 0.1 to 2.0 μm is formed on the upper electrode layer 15 by, eg, sputtering. Further, the inter-element shield layer 54 made of, for example, NiFe, NiFeCo, CoFe, FeN, FeZrN or the like and having a thickness of about 0.3 to 4 μm is formed on the first nonmagnetic layer 53 by, for example, sputtering or frame plating. Form.

Next, as shown in FIG. 5B, a second nonmagnetic layer made of Al ₂ O ₃ or the like and having a thickness of about 0.3 to 1.0 μm is formed on the inter-element shield layer 54 by, eg, sputtering. 55 is formed. Further, a backing coil layer 560 made of, for example, Cu or the like and having a thickness of about 0.5 to 3 μm is formed on the second nonmagnetic layer 55 by, for example, frame plating or the like so as to cover the backing coil layer 560. In addition, a backing coil insulating layer 561 having a thickness of about 0.1 to 5 μm made of, for example, a heat-cured resist layer or the like is formed so as to fill between the patterns of the same layer. Thereby, the backing coil part 56 is formed. Furthermore, a third nonmagnetic layer 57 made of, for example, Al ₂ O ₃ or the like and having a thickness of about 0.3 to 5 μm is formed by, for example, a sputtering method so as to cover the backing coil portion 56. Thereafter, the third nonmagnetic layer 57 is planarized by, for example, a chemical mechanical polishing (CMP) method.

  Next, as shown in FIG. 5C, on the planarized third nonmagnetic layer 57, for example, any two of Ni, Fe, and Co are formed by sputtering, frame plating, or the like. A main magnetic pole main layer 5800 having a thickness of about 0.01 to 0.5 μm made of three alloys, or an alloy having these elements as main components to which a predetermined element is added, and similarly, for example, a sputtering method or a frame plating method The main magnetic pole having a thickness of about 0.5 to 3 μm made of, for example, an alloy made of any two or three of Ni, Fe and Co, or an alloy to which a predetermined element is added as a main component. An auxiliary layer 5801 is formed. Thereby, the main magnetic pole layer 580 is formed.

Next, a gap layer 581 made of, for example, Al ₂ O ₃ or DLC or the like having a thickness of about 0.01 to 0.5 μm is formed on the main magnetic pole layer 580 by, eg, sputtering, and then on the gap layer 581. For example, a coil base insulating layer 582 having a thickness of about 0.1 to 5 μm made of a heat-cured resist layer or the like is formed, and the coil base insulating layer 582 is made of, for example, Cu or the like by frame plating or the like. A coil layer 583 having a thickness of about 0.5 to 3 μm is formed.

Further, a coil insulating layer 584 having a thickness of about 0.5 to 5 μm made of, for example, a heat-cured resist layer is formed so as to cover the coil layer 583. Further, the coil insulating layer 584 is covered with, for example, an alloy made of any two or three of Ni, Fe, and Co, or an alloy to which a predetermined element is added as a main component, and the like. An auxiliary magnetic pole layer 585 having a thickness of about 0.5 to 5 μm is formed. The formation of the electromagnetic coil element 58 is completed through the above steps. Finally, an insulating film made of, for example, Al ₂ O _{3 is} formed so as to cover the MR effect element 10 and the electromagnetic coil element 58, and then the insulating film is covered by flattening using, for example, a CMP method. The layer 59 is formed, and signal terminal electrodes for the MR effect element 10 and the electromagnetic coil element 58 are formed, and the wafer thin film process is completed.

  6 (A) to 6 (G) are cross-sectional views illustrating the main part in one embodiment of the method for manufacturing an MR effect element according to the present invention. In addition, the cross section in the same figure is a surface parallel to ABS except FIG. 6 (F1) and (F2).

  First, as shown in FIG. 6A, on the lower electrode layer 12, for example, a first base film 13a made of Ta, Hf, Nb, Zr, Ti, Mo, W or the like and having a thickness of about 1 to 5 nm is formed. For example, a second base film 13b having a thickness of about 1 to 2 nm made of Ru or the like, an antiferromagnetic layer 100 having a thickness of about 5 to 15 nm made of IrMn, PtMn, NiMn, RuRhMn, or the like, and CoFe or the like, for example. A first ferromagnetic film 101a having a thickness of about 2 to 3 nm and a thickness of about 0.8 nm made of one or two or more alloys of, for example, Ru, Rh, Ir, Cr, Re, and Cu. A nonmagnetic film 101b and a second ferromagnetic film 101c made of, for example, CoFe and having a thickness of about 2 to 3 nm are sequentially formed by a sputtering method or the like.

  Next, a metal film made of, for example, Al, AlCu or the like and having a thickness of about 0.5 to 1 nm is formed on the formed second ferromagnetic film 101c by a sputtering method or the like. Next, the metal film is oxidized by oxygen introduced into the vacuum apparatus or by natural oxidation to form the tunnel barrier layer 102. Next, on the formed tunnel barrier layer 102, for example, a high polarizability film 103a made of CoFe or the like with a thickness of about 1 nm, a soft magnetic film 103b made of NiFe or the like with a thickness of about 3 to 4 nm, and Ta, for example, A cap layer 14 made of Ru, Hf, Nb, Zr, Ti, Mo, W or the like and having a thickness of about 5 to 20 nm is sequentially formed by a sputtering method or the like. Thus, the MR effect multilayer film 60 is formed.

  Next, as shown in FIG. 6B, a resist 61 forming a resist pattern for liftoff, for example, is formed on the MR effect multilayer film 60. Thereafter, as shown in FIG. 6C, the MR effect multilayer body 60 'is formed by performing ion beam etching with, for example, Ar ions on the MR effect multilayer film 60 using the resist 61 as a mask. . At this time, it is preferable to rotate the MR effect multilayer film 60 together with the substrate and irradiate the ion beam at a predetermined incident angle.

Next, after the MR effect multilayer 60 ′ is formed, as shown in FIG. 6D, for example, a nonmagnetic insulating layer 16 made of Al ₂ O ₃ , SiO ₂ or the like and having a thickness of about ₃ to 20 nm, A bias layer 17 made of CoFe, NiFe, CoPt, CoCrPt or the like is sequentially formed by a sputtering method or the like. Thereafter, as shown in FIG. 6E, the resist 61 is peeled off by lift-off.

  Thereafter, as shown in FIGS. 6 (F1) and (F2), the MR effect multilayer body 60 ′ is further patterned by a photolithography method or the like to form the base layer 13, the MR effect multilayer body 11 and the cap layer 14, Next, the insulating film 62 is formed by sputtering, ion beam sputtering, or the like. 6F1 is a cross-sectional view taken along the line AA of FIG. 6F2, and FIG. 6F2 is a view of the element formation surface of the wafer substrate as viewed from directly above. The line is orthogonal to the track width direction. Thereafter, as shown in FIG. 6G, the upper magnetic pole layer 15 is formed on the cap layer 14, and the manufacturing process of the main part of the MR effect element 10 is completed.

  FIG. 7 is a schematic view showing an embodiment of a machining process in the method of manufacturing a thin film magnetic head according to the present invention.

  As shown in FIG. 7A, a large number of magnetic head element patterns 71 are formed in a matrix on the element forming surface of a thin film magnetic head wafer 70 which is a wafer substrate on which the wafer thin film process is completed. Yes. The magnetic head element pattern 71 is a portion mainly serving as an MR effect element, an electromagnetic coil element, and a signal terminal electrode in each slider formed through a machining process described below.

  First, the thin film magnetic head wafer 70 is cut by bonding to a cutting / separating jig using resin or the like, and a plurality of magnetic head element patterns 71 are arranged in a line as shown in FIG. 7B. The processing bar 72 is cut out. Next, the processing bar 72 is bonded to a polishing jig using a resin or the like, and the end surface 720 on the ABS side of the processing bar 72 is subjected to rough polishing as MR height processing. As shown in FIG. 7C, this MR height processing is performed until the magnetic head element 76 is finally exposed on the head end surface 780 and the MR effect laminate of the MR effect element reaches a predetermined MR height. Is called.

  Next, as shown in FIG. 7D, a first magnetic field application process for applying the first magnetic field 34 is performed on the processing bar 72 using the electromagnet 73 (step 12 in FIG. 2). Next, the processing bar 72 that has been subjected to the same processing is subjected to an annealing process for releasing processing distortion due to machining (step 13 in FIG. 2). Thereafter, as shown in FIG. 7E, a second magnetic field application process for applying the second magnetic field 36 to the processed bar 72 that has been subjected to the annealing process is performed using the electromagnet 74 (FIG. 2). Step 14).

  Next, fine finishing is performed on the formed ABS, and then a protective film made of, for example, diamond-like carbon (DLC) is formed on the head end surface 780. Thereafter, the processing bar 72 on which the protective film is formed is bonded to a rail forming jig using a resin or the like, and a process of forming a rail on the ABS using a photolithography method, an ion beam etching method, or the like is performed. Thereafter, this processing bar is bonded to a cutting jig using a resin or the like, grooving processing is performed, and then the cutting processing is performed, so that the processing bar 72 is made into individual sliders as shown in FIG. 77. Thus, the machining process for forming the slider is completed, and the manufacturing process of the thin film magnetic head is completed.

  As shown in FIG. 7F, the slider (thin film magnetic head) 77 manufactured in this way includes an ABS 78 processed so as to obtain an appropriate flying height, and a magnetic head formed on the element formation surface 79. An element 76 and four signal terminal electrodes 75 exposed from the layer surface of the covering layer 59 formed on the element formation surface 79 are provided. Here, the magnetic head element 76 includes the MR effect element 10 for reading and the electromagnetic coil element 58 for writing. Here, two of the four signal terminal electrodes 75 are connected to the MR effect element 10 and the electromagnetic coil element 58, respectively. One end of the MR effect element 10 and the electromagnetic coil element 58 reaches the head end surface 780 on the ABS 78 side. When these ends face the magnetic disk, reading by sensing the signal magnetic field and writing by applying the signal magnetic field are performed.

  The effects of using the method of manufacturing a thin film magnetic head (MR effect element) according to the present invention will be described below using heads according to various examples and comparative examples.

In the heads according to the following examples and comparative examples, one of the characteristics used for comparison is the relationship between the externally applied magnetic field H _EX and the element resistance R _MR in the TMR effect element provided in each head. It is the RH characteristic as a characteristic. Measurements were made using a QST device. Another index used is a noise count profile (NCP) described below.

  FIG. 8 is a graph for explaining an NCP measurement method.

  In the NCP measurement, first, the output of the TMR effect element was passed through a 200 MHz band wide band amplifier to cancel the DC component, and then a signal with a predetermined bandwidth was taken out. FIG. 8A shows this signal in a graph with time on the horizontal axis and voltage on the vertical axis. According to the figure, popping noise popping out from a baseline having a predetermined width is observed.

Here, with respect to this signal, decided a certain threshold voltage _{v TH,} during a predetermined time _{t MEAS} (e.g. 500 ms), the threshold voltage _{v TH} signal has counted the number of times _{C N} having traversed. In addition, it counts the number of times _{C N} to change the threshold voltage _{v TH} across at each threshold voltage _{v TH.} FIG. 8 (B) thus obtained is a graph showing the relationship between the number of times C _N having traversed the threshold voltage v _TH. The width of the profile curve in the figure basically corresponds to the baseline width in FIG. 8A. However, if there is popping noise in the signal, the profile curve has a hem or a shoulder. It will end up.

Here, in FIG. 8 (B), the number C _N of near 0V ends up projecting several orders of magnitude larger, the presence of the popping noise becomes inconspicuous. Therefore, FIG. 8C shows a graph in which the vertical axis for dealing with this is taken. The vertical axis of the graph shown in FIG. 8C is the normalized count number, that is, log ₁₀ (C _N / MAX (C _N )) × 100 (%). Is normalized as 100%. As a result, the frequency and magnitude of the popping noise are clearly represented in a graph, and the noise characteristics can be easily evaluated. The characteristics shown in FIG. 8C are defined as NCPs, and the following examples and comparative examples were evaluated using the NCPs and the above-described RH characteristics.

(Examples 1-3 and Comparative Examples 1-3)
9, FIG. 10 and FIG. 11 are graphs showing RH characteristics and NCP at each processing stage in the heads according to Embodiments 1 to 3, respectively.

The manufacturing method of each head in Examples 1 to 3 was as described in Step 1 to Step 18 of FIG. Here, the magnitude of the first magnetic field in the first magnetic field application process is 6 kOe (about 480 kA / m), the annealing temperature in the annealing process is 180, 200, and 220 ° C., and the annealing time is 1 hour. It was. Further, the magnitude of the second magnetic field in the second magnetic field application process was 6 kOe (about 480 kA / m). In the NCP graph, the threshold voltage v _{TH on} the horizontal axis is a threshold for the element output, and is obtained by dividing the threshold for the amplifier output by 1000 that is the amplification factor of the amplifier.

  According to (A1) and (A2) of FIGS. 9 to 11, each head of Examples 1 to 3 is a good R− that is linear and hardly shows hysteresis before the first magnetic field application process. A good NCP with suppressed H characteristics and popping noise is shown. When the first magnetic field application process and the annealing process are performed on these heads, as shown in (B1) and (B2) of FIGS. In the −H characteristic, the slope of a part of the curve becomes large and hysteresis is observed, and a shoulder indicating that popping noise is generated with a considerable frequency in NCP is seen.

  This is because the magnetization of the bias layer “breaks down” due to the first magnetic field application process and faces in the first direction as shown in FIG. As a result of this "breakdown", the magnetization of the free magnetic layer is not stable, and irregular magnetic domains are formed in the layer, and magnetic popping noise occurs due to irregular movement of the domain wall that is the boundary of this magnetic domain. Resulting in.

  However, after that, by performing the second magnetic field application process, good RH characteristics and NCP are finally obtained as shown in (C1) and (C2) of FIGS. .

  12, 13 and 14 are graphs showing RH characteristics and NCP at each processing stage in the heads according to Comparative Examples 1 to 3, respectively.

The manufacturing method of each head in Comparative Examples 1 to 3 was the same as in Examples 1 to 3 except for Step 12. That is, in these heads, the first magnetic field application process (step 12) was omitted and not performed. In the CNP graph, the threshold voltage v _{TH on} the horizontal axis is the threshold for the element output as in FIGS. 9 to 11, and is obtained by dividing the threshold for the amplifier output by 1000 which is the amplification factor of the amplifier. .

  According to (A1) and (A2) of FIGS. 12 and 13, each head of Comparative Examples 1 and 2 is a good RH characteristic that is linear and hardly shows hysteresis before the annealing process, and It shows a good NCP with suppressed popping noise. On the other hand, in the head of Comparative Example 3, clear popping noise is observed before the annealing process, as shown in the RH characteristics and NCPs of (A1) and (A2) in FIG. .

  When these heads are then annealed, as can be seen from the RH characteristics and NCP shown in (B1) and (B2) of FIGS. However, it can be seen that a considerable amount of magnetic popping noise due to the irregular movement of the domain wall as described above occurs. After that, when the second magnetic field application process was performed on these heads, as can be seen from the RH characteristics and NCP shown in (C1) and (C2) of FIGS. It can be seen that there are still a significant number of magnetic popping noise, unlike ~ 3.

  That is, in the heads of the first to third embodiments, the first magnetic field application process and the subsequent annealing process certainly cause the magnetization of the bias layer to “break down” and temporarily increase the magnetic popping noise. However, since the magnetization fixed layer is annealed while receiving a bias magnetic field in the first direction from the bias layer, the magnetization inclination or dispersion originally possessed by the magnetization fixed layer due to the heat treatment or the like so far is extremely high. Can be kept small. As a result, in the heads of Examples 1 to 3, after re-magnetization of the bias layer by the second magnetic field application process, finally, very good RH characteristics and NCP with suppressed popping noise are realized. Is done.

  On the other hand, in the heads of Comparative Examples 1 to 3, since the magnetization of the magnetization fixed layer is annealed while being tilted or dispersed during the annealing process, the magnetization is fixed as it is or irregular magnetic domains are formed. It is easily formed. As a result, many magnetic popping noises exist even after the second magnetic field application process.

  As described above, according to the results of Examples 1 to 3 and Comparative Examples 1 to 3, in the manufacturing method of the present invention, the first magnetic field application process is performed and biased before the annealing process in order to release the machining distortion caused by machining. It is understood that it is very important to “break down” the magnetization of the layer. By such processing steps, it is possible to avoid an increase in magnetic popping noise due to the annealing process, and further reduce the magnetic popping noise by suppressing the inclination or dispersion of magnetization that had been present before the annealing process. It becomes.

  All the embodiments described above are illustrative of the present invention and are not intended to be limiting, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

It is sectional drawing which shows schematically the layer structure of the MR effect element which concerns on the manufacturing method of this invention. 3 is a flowchart schematically showing an embodiment of a method of manufacturing a thin film magnetic head according to the present invention. It is the schematic for demonstrating the effect in one Embodiment of the manufacturing method of the thin film magnetic head by this invention. It is the schematic for demonstrating the effect in other embodiment of the manufacturing method of the thin film magnetic head by this invention. It is sectional drawing which shows one Embodiment of the wafer thin film process in the manufacturing method of the thin film magnetic head by this invention. It is sectional drawing explaining the principal part in one Embodiment of the manufacturing method of MR effect element by this invention. It is the schematic which shows one Embodiment of the machining process in the manufacturing method of the thin film magnetic head by this invention. It is a graph for demonstrating the measuring method of NCP. 6 is a graph showing RH characteristics and NCP at each processing stage in the head according to Example 1; 6 is a graph showing RH characteristics and NCP at each processing stage in the head according to Example 2. 12 is a graph showing RH characteristics and NCP in each processing stage in the head according to Example 3. 6 is a graph showing RH characteristics and NCP at each processing stage in the head according to Comparative Example 1; 10 is a graph showing RH characteristics and NCP at each processing stage in a head according to Comparative Example 2; 10 is a graph showing RH characteristics and NCP at each processing stage in a head according to Comparative Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 MR effect element 100 Antiferromagnetic layer 101 Magnetization fixed layer 101a 1st ferromagnetic film 101b Nonmagnetic film 101c 2nd ferromagnetic film 102 Tunnel barrier layer 103 Magnetization free layer 103a High polarizability film | membrane 103b Soft magnetic film 11 MR Effect laminated body 12 Lower electrode layer 13 Base layer 13a First base film 13b Second base film 14 Cap layer 15 Upper electrode layer 16 Nonmagnetic insulating layer 17 Bias layer 30, 31, 32 Magnetization 33, 35, 37 Bias magnetic field 34, 40, 41 First magnetic field 36 Second magnetic field 50 Wafer substrate 51 Underlying insulating layer 53 First nonmagnetic layer 54 Inter-element shield layer 55 Second nonmagnetic layer 56 Backing coil portion 560 Backing coil layer 561 Backing Coil insulating layer 57 Third nonmagnetic layer 58 Electromagnetic coil element 580 Main magnetic pole layer 5800 Magnetic pole main layer 5801 Main magnetic pole auxiliary layer 581 Gap layer 582 Coil base insulating layer 583 Coil layer 584 Coil insulating layer 585 Auxiliary magnetic pole layer 59 Covering layer 60 MR effect multilayer 60 'MR effect multilayer 61 Resist 62 Insulating film 70 Thin film magnetic head Wafer 71 Magnetic head element pattern 72 Processing bar 720 ABS end face 73, 74 Electromagnet 75 Signal terminal electrode 76 Magnetic head element 77 Slider 78 ABS
780 Head end surface 79 Element forming surface

Claims (11)

An antiferromagnetic layer, a magnetization fixed layer that is exchange-coupled to the antiferromagnetic layer and whose magnetization is fixed in the first direction in the laminated surface, and a magnetization whose magnetization direction changes in response to an external magnetic field A magnetoresistive stack including a free layer, and a magnetization fixed layer and a nonmagnetic intermediate layer provided between the magnetization free layer;
And a bias layer for applying a bias magnetic field in a second direction in a laminated plane perpendicular to the first direction and positioned near the end of the magnetization free layer to the magnetization free layer. A method of manufacturing a magnetoresistive element,
The formed magnetoresistive effect laminate and the bias layer are subjected to a first magnetic field application process in which a first magnetic field larger than the coercive force of the bias layer is applied in the first direction, and heat is applied. A manufacturing method comprising: performing a second magnetic field application process in which a second magnetic field larger than the coercive force of the bias layer is applied in the second direction after the annealing process is performed.   After or during the formation of the antiferromagnetic layer and the magnetization fixed layer, a magnetic field is applied in the first direction while heating to fix the magnetization direction of the magnetization fixed layer in the first direction. Further, after or during the formation of the magnetization free layer and the bias layer, a magnetic field is applied in the second direction to magnetize the bias layer in the second direction, and then the first The manufacturing method according to claim 1, wherein the magnetic field application process, the annealing process, and the second magnetic field application process are performed.   The manufacturing method according to claim 1, wherein the nonmagnetic intermediate layer is a tunnel barrier layer having electrical insulation, and the magnetoresistive effect element is a tunnel magnetoresistive effect element.   4. The manufacturing method according to claim 1, wherein the bias layer is provided in the vicinity of both ends of the magnetization free layer in the second direction. 5.   The manufacturing method according to any one of claims 1 to 4, wherein an annealing temperature of the annealing treatment is 160 ° C or higher and 220 ° C or lower.   6. The manufacturing method according to claim 1, wherein the first magnetic field is an AC demagnetizing magnetic field whose amplitude gradually decreases.   A manufacturing method of a thin film magnetic head provided with a magnetoresistive effect element for reading data, wherein the magnetoresistive effect element is manufactured by the manufacturing method according to claim 1.   The manufacturing method according to claim 7, wherein the first direction is a direction perpendicular to the track width direction, and the second direction is a track width direction.   A magnetic head element having a magnetoresistive effect element is formed on the element forming surface of the substrate, and a processing bar in which the magnetic head elements are arranged in a row is cut out from the substrate on which the magnetic head element is formed. The manufacturing method according to claim 8, wherein the first magnetic field application process, the annealing process, and the second magnetic field application process are performed on a bar.   The annealing treatment is performed after the roughing for the height processing for determining the position of the air bearing surface and the MR height is performed on the processing bar and before the fine polishing is performed. The manufacturing method as described in.   A magnetic head element having a magnetoresistive effect element is formed on the element forming surface of the substrate, and a processing bar in which the magnetic head elements are arranged in a line is cut out from the substrate on which the magnetic head element is formed. 11. The manufacturing method according to claim 7, wherein the second magnetic field application process is performed on the slider after cutting and separating into a slider. 11.

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