JP3937558B2 - Manufacturing method of spin valve type magnetoresistive head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thin film magnetic head, and more particularly to a method of manufacturing a thin film magnetic head using a spin valve magnetoresistive element.
[0002]
[Prior art]
Giant magnetoresistive elements (GMR elements) have been spotlighted as conversion elements that detect the amount of magnetism converted to the magnitude of electrical resistance, and one of the typical sensor elements is a spin valve element. . The spin valve element is configured as a laminated film having a sandwich structure in which one nonmagnetic conductive layer is sandwiched between two magnetic layers, and one magnetic layer (referred to as a pinned layer) is predetermined. Is magnetized in a fixed direction, and the other magnetic layer (referred to as a free layer) is magnetized in a direction that changes in accordance with an external magnetic field, and an electric resistance exhibited by a conductive layer (referred to as a spacer layer) sandwiched therebetween is exhibited. This utilizes a phenomenon in which the magnitude changes according to the magnetization direction of the free layer. The magnitude of the electrical resistance of the spacer layer is detected as the value of the voltage drop between them by passing a sense current through it.
[0003]
The schematic structure of the spin valve element is illustrated in FIG. 16A schematically shows a state in which the sense current Is is supplied to the spin valve element 10 for use, and FIG. 16B shows a detailed configuration of the spin valve element 10 disassembled. The pinned layer 1 is a soft magnetic film, and is backed in an exchange coupling manner with a magnetized hard antiferromagnetic film 11 (usually, only the soft magnetic film, or the antiferromagnetic film, as appropriate). And a magnetization vector (arrow Mp) in which the soft magnetic film 1 is fixed in the same direction due to the influence of magnetization of the antiferromagnetic film 11. This pinned layer 1 is meaningful in that the direction of the magnetization vector is fixed, and the difficulty of movement of magnetization due to the influence of an external magnetic field is generally referred to as an exchange bias magnetic field Hua. The magnetization direction of the pinned layer is not easily changed by a magnetic field. The free layer 2 is a soft ferromagnetic film, and the direction of magnetization easily changes in accordance with magnetic induction (magnetostatic coupling) from a nearby external magnetic field that affects the free layer 2. In general, bias magnetization (arrow Mf) in a direction orthogonal to the magnetization direction of the pinned layer 1 is given to the free layer 2 as the direction of magnetization at the operation center, the free layer 2 is exposed to an external magnetic field, By utilizing the fact that the magnitude of the electric resistance of the spacer layer 3 changes around a certain value by rotating the magnetization direction of the free layer 2 to the left or right from the direction of the bias magnetization according to the magnitude of the magnetic field. The magnetoelectric conversion element is used.
[0004]
By the way, the magnetism of a magnetic material is influenced by temperature, and even in a thin film magnetic head using a spin valve element, it is necessary to consider the temperature. Heat generation due to current in use and frictional heat due to collision with the recording medium are problems. For the pinned layer, the exchange bias magnetic field Hua decreases as the temperature rises, and when it rises to a temperature called the blocking temperature, Hua becomes 0 at higher temperatures. As for the free layer, when the temperature is high, the element is deteriorated due to diffusion of alloy components due to temperature and electromigration due to current.
[0005]
Specifically, the wafer process of the thin film magnetic head and other processing processes include a heat treatment step with heating of about 100 to 250 ° C. For example, a resist flow process of an insulator in a wafer process, an adhesion process of a magnetic head to a jig in a processing process (in the case of a hot melt adhesive), and the like are applicable. Further, when the magnetic head is in use, the temperature may rise to 100 to 200 ° C. due to heat generation of the element itself due to the sense current. Furthermore, as the element is miniaturized, it is conceivable that the current instantaneously becomes 200 ° C. or higher due to an electric current caused by static electricity spark. Thus, an MR head using a spin valve element inevitably involves an increase in temperature of the element due to heat treatment and use.
[0006]
Therefore, in order to compensate for the inconvenience due to such temperature rise, the uniaxial anisotropy of the magnetic thin film layer (fixed layer) that receives the exchange bias magnetic field does not change in the temperature range encountered by the element. Materials with a high blocking temperature have been applied along with the practical application of spin valve heads. For example, FeMn, which is generally known as an antiferromagnetic film for exchange bias, has a blocking temperature of 140 ° C., whereas IrMn, which is said to have a relatively high blocking temperature, is 240 ° C. The blocking temperature of PtMn is 380 ° C. When an external magnetic field is applied, the magnetization of the pinned layer is affected even below the blocking temperature, and the exchange bias magnetic field Hua actually decreases as the temperature increases. Therefore, the blocking temperature of the element is required to be 300 ° C. or higher. In this respect, PtMn with a high blocking temperature is suitable for this purpose.
[0007]
[Problems to be solved by the invention]
However, it is known that an antiferromagnetic film such as PtMn does not exhibit antiferromagnetism only by being formed, and has properties only after performing ordered heat treatment. For this reason, in the magnetization process of the antiferromagnetic film, the magnetizing process is performed after the regularizing heat treatment. In general, an antiferromagnetic film having a high blocking temperature has a high ordering temperature. Therefore, when a material having a high blocking temperature is used, an ordered heat treatment at a high temperature is interposed. When the process temperature is 300 ° C. or higher, diffusion of alloy elements and electromigration occur in the magnetic film used for the free layer, which causes deterioration of the element. In particular, since nickel in the nickel alloy used for the free layer diffuses at a fairly low temperature, the device characteristics are greatly deteriorated when heat treatment is performed at a high temperature of 300 ° C. or higher. Therefore, if an antiferromagnetic film having a high blocking temperature, such as PtMn, is used to maintain the exchange bias magnetic field Hua, the spin rate does not cause a significant deterioration in characteristics of the entire device due to an adverse effect on the free layer in the manufacturing process. It was difficult to manufacture a valve magnetic head.
[0008]
Therefore, the present invention is devised so that a regularized heat treatment can be performed at a relatively low temperature for a magnetic material having a high blocking temperature, thereby stabilizing the characteristics of the pinned layer without degrading the characteristics of the free layer. An object of the present invention is to provide a method for manufacturing a thin film magnetic head using a valve element.
[0009]
[Means for Solving the Problems]
The method for manufacturing a spin valve magnetoresistive head according to the present invention comprises a step of preparing a substrate, and an antiferromagnetic film having a blocking temperature of 300 ° C. or higher on the substrate. PtMn film Forming a spin valve stack including a pinned layer, a nonmagnetic high-conductivity spacer layer, and a soft ferromagnetic film free layer; and heat-treating the spin valve stack in an oxygen atmosphere; Subjecting the spin valve laminate to heat treatment in an oxygen atmosphere at a temperature that imparts uniaxial anisotropy to the pinned layer while applying a magnetic field perpendicular to the track width direction; Uniform anisotropy of the easy axis of magnetization is applied to the free layer at a temperature and magnetic field intensity at which the anisotropic dispersion angle of the aligned magnetic thin film layer is within 20 degrees of the alignment direction while applying a magnetic field in the track width direction. Performing a heat treatment to be applied.
[0010]
Furthermore, in the method of manufacturing the spin valve magnetoresistive head according to the present invention, in order to obtain a preferable result, the heat treatment step in the oxygen atmosphere is performed by exposing it to an oxygen plasma of 300 ° C. or lower.
[0011]
Further, in the method of manufacturing a spin valve magnetoresistive head according to the present invention, in order to obtain a preferable result, the ordered heat treatment step is performed to form a regularized lattice in the antiferromagnetic film and the soft ferromagnetic film. At a temperature that causes
[0012]
Furthermore, in the method for manufacturing a spin valve magnetoresistive head according to the present invention, the ordered heat treatment is performed at a temperature of 300 ° C. or lower, preferably 250 to 280 ° C., in order to obtain a preferable result.
[0013]
Further, in the method of manufacturing a spin valve magnetoresistive head according to the present invention, in order to obtain a preferable result, the heat treatment that imparts uniaxial anisotropy to the free layer is subjected to the regularization. Heat treatment Below the temperature, the anisotropic dispersion angle of the magnetization of the pinned layer is carried out at a temperature in a range that exhibits only a change within 20 degrees from the direction before the heat treatment.
[0014]
In the method of manufacturing the spin valve magnetoresistive head according to the present invention, in order to obtain a preferable result, a final heat treatment for imparting uniaxial anisotropy to the free layer is performed by applying a magnetic field in the track width direction to 200 ° C. or less. At a temperature of
[0015]
The method of manufacturing a spin valve magnetoresistive head according to the present invention includes a step of bonding a hard ferromagnetic thin film layer to both ends of the free layer in the track width direction. This step is preferably performed at a stage prior to the final heat treatment.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 5 are perspective views schematically showing the main part of the magnetic head at each successive stage in the manufacturing method of the present invention. FIG. 1A shows a substrate 20 prepared first in the present invention, which is formed on the surface of an AlTiC wafer 21 which becomes a slider body, for example, Al. ₂ O _Three A protective undercoat film 22 is formed, a lower shield film 23 such as NiFe is formed thereon, and an Al shield is further formed thereon. ₂ O _Three The gap film 24 is attached.
[0017]
Further, as shown in FIG. 1B, a hard ferromagnetic layer 32a (for example, CoCrPt) serving as a hard magnet for uniaxial anisotropy control of the free layer (formed later) is further formed thereon. A metal film 33a having a high conductivity and serving as an electrode lead for supplying current to the spacer layer at 20 to 100 nm is formed by sputtering. In place of this thin film 32a of hard ferromagnetic material, an equivalent effect can be obtained by attaching a film in which a soft magnetic layer and an antiferromagnetic material layer are magnetically coupled. Here, the hard ferromagnetic thin film layer 32a is made of a material having a high coercive force, a high squareness ratio, and a high electrical resistance, and a soft magnetic thin film layer of a free layer of a spin valve element formed in a later process. A longitudinal bias for maintaining a single domain state in the track width direction is generated. As will be described later, a soft ferromagnetic thin film forming a free layer is formed in a taper shape in the track width direction. Then, the inclined portion of the taper comes into contact with the laminated film of the spin valve element.
[0018]
Next, as shown in FIG. 1 (c), a lead cut resist 34 for cutting the hard ferromagnetic layer 32a and the conductive metal film 33a into a predetermined opposing bipolar structure shape is applied thereon. The region not masked by the resist 34 is etched away by a unidirectional method such as ion milling. In this case, as shown in FIG. 2 (a), the resist 34 is heated and melted to flow the inner end edge portion, so that ion milling (arrow 39) is performed as shown in FIG. 2 (b). (For example, by argon plasma) is performed in an inclined manner, and both inner edge portions of the lead layer 33 made of a conductive metal film and the hard magnet layer 32 made of a hard ferromagnetic layer are formed in a tapered shape. Then, the resist layer 34 used as a mask is removed by a selective etching method such as RIE, and a shape as shown in FIG.
[0019]
Next, the process of laminating the spin valve film will be described with reference to FIG. As described above, a CoZrNb / NiFe layer for a free layer is formed on a structure in which valleys having tapered sides are formed, and a Cu layer for a spacer layer is formed thereon via a CoFe film. After attaching the layer, a PtMn / Ti layer for a fixing layer is further formed thereon via a CoFe film to form an SV (spin valve) laminated film 40a as shown in FIG. . These films are formed by continuous lamination to a precise thickness using an ultra-high vacuum apparatus.
[0020]
In the above embodiment, in order to form the spin valve laminated film 40a, the lead portion 33 and the hard magnet portion 32 which are inclined first are formed, and the spin valve film 40a is laminated thereon. However, instead of this, a spin valve film is first formed and the element shape is formed with a lift-off resist using a lift-off method, as conventionally performed in the manufacture of a junction type MR head. The same function can be achieved by tilting the coupling end of the element by a dry etching method such as milling using the resist as a mask and laminating a hard magnetic film for longitudinal bias and a lead film for electrical conduction on it. The structure is completed.
[0021]
Next, before the ordered heat treatment is performed on the spin valve stacked film 40a, O which is a feature of the present invention. ₂ Heat treatment is performed in an atmosphere. For example, using RIE, O ₂ O with a high frequency power of 220 W at a pressure of 1.33 Pa (10 mTorr) ₂ Treatment is performed for 5 to 10 minutes using plasma. In addition to performing this treatment using plasma, a slight oxygen of 1.33 to 6.65 Pa (10 to 50 mTorr) is introduced into a vacuum heat treatment furnace, and the heat treatment is performed at a temperature of about 200 ° C. for 1 hour or longer. A similar effect can be obtained. In the case of plasma treatment, if the time is 3 to 4 minutes or longer, the effect is not greatly different. And until 20 minutes, there is no problem of deterioration of characteristics due to oxidation of the element.
[0022]
Next, regularizing heat treatment is performed at a temperature that gives uniaxial anisotropy to the pinned layer while applying a magnetic field in a direction perpendicular to the track width direction to the spin valve laminated film 40a heat-treated in the oxygen atmosphere. PtMn In layers On the other hand, this ordered heat treatment is performed at a temperature of 300 ° C. or lower. This process is the same as that described above. ₂ After the heat treatment in the atmosphere, it is performed within several hours. If this is carried out after standing for 24 hours or more, the desired characteristics cannot be obtained.
[0023]
Next, the process proceeds to a processing step for making the spin valve laminated film 40a into the shape of the magnetoresistive element. As shown in FIG. 3B, the resist 41 is cut into an element shape and etched by a plasma etching method such as milling using this resist 41 as a mask. As shown in FIG. A spin valve element 40 bridged between the layer 33 and the hard magnet layer 32 is formed. In the above description, the stacking order of the spin valve stacked film 40a is the order of the free layer, the spacer layer, and the fixed layer from the bottom, but this order may be reversed.
[0024]
Thereafter, as a preparation for the formation of the next writing inductive head element, as shown in FIG. 4A, an insulating material such as alumina is formed on the whole after the above MR head element is formed. The gap layer 42 is formed.
[0025]
Subsequently, as shown in FIG. 4B, a seed layer (underlayer) 51 such as NiFe as a plating underlayer for forming the upper shield film of the inductive head element is formed with a gap layer 42 by a method such as sputtering or vapor deposition. The upper shield pattern is cut with a photoresist (not shown here, but it is a pattern that is much larger than the range shown here), and as shown in FIG. Further, the upper shield film 52 is formed by a method such as plating. The upper shield film 52 is formed as the upper shield 52 by milling removal of unnecessary portions of the underlayer 51 and etching removal of patterns other than the upper shield. The upper shield 52 also serves as the lower core of the write head.
[0026]
Next, the upper surface of the upper shield 52 is flattened, a write gap is formed thereon, a coil and an insulator layer are deposited, and then an upper core is formed. If necessary, the lower core 52 and the upper core are processed into a desired shape in order to ensure characteristics. As a result, for example, as shown in FIG. In FIG. 5, 40 is a spin valve element as a read head, 32 is a hard magnet for longitudinal bias of the spin valve element, 33 is a read electrode for sense current of the spin valve element, 52 is a lower core of the write head, 53 is A write gap, 54 is a write pole, 55 is a protective layer, 56 is a write coil, 57 is an insulator between the coils, and 58 is an upper core.
[0027]
Although the above description is about one head element, in an actual manufacturing process, a large number of elements (for example, 57 × 133) are arranged in a matrix on a single slider material wafer. Make what you want at once. A magnetic field that is effectively applied to each element in the easy magnetization axis direction (track width direction) of the soft ferromagnetic thin film layer forming the free layer in the wafer state is several tens of kA in the wafer including the multiple head elements. The final heat treatment is performed at a temperature not exceeding 200 ° C., for example, a temperature of 180 to 200 ° C., in a state where a magnetic field of about / m (several hundreds Oe) is applied. As a result, the characteristics of the magnetic layers such as the magnetic thin film layer, the lower shield layer, the upper shield layer, the write pole layer, and the upper core layer of the free layer are stabilized.
[0028]
Next, a processing process for separately manufacturing each individual slider from the wafer will be described. 6 to 10 are schematic process diagrams of the processing process. FIG. 6A shows a slider material wafer 60 having a large number of magnetic head elements formed on the upper surface. First, the wafer 60 is placed on a cutting jig 71 as shown in FIG. 6B. Bonding with hot melt resin 72. In this case, bonding with resin is performed at a temperature (for example, 100 to 150 ° C.) that does not change the uniaxial anisotropy of the soft ferromagnetic thin film layer in the processed magnetic head element. There is a need. Subsequently, as shown in FIG. 7A, the wafer 60 is cut by a cutting blade 73 and separated into, for example, 133 slider rows. Even when each row 61 is removed from the resin 72 to be in the state of FIG. 7B, it is necessary to perform desorption at a temperature that does not change the uniaxial anisotropy of the soft ferromagnetic thin film layer.
[0029]
Next, each cut row 61 is bonded to a grinding / polishing jig 74 as shown in FIG. Also in this case, it is necessary to perform adhesion at a temperature that does not change the uniaxial anisotropy of the soft ferromagnetic thin film layer. The row 61 mounted on the jig 74 is ground and polished to adjust the throat height of each magnetic head. When this is done, the row 61 is removed from the jig 74, but it is also necessary to detach at a temperature that does not change the uniaxial anisotropy of the soft ferromagnetic thin film layer. The row 61 thus ground and polished is bonded to a rail forming jig 75 as shown in FIG. Next, as shown in FIG. 9A, a dry film 76 for photolithography is laminated on the rows 61 arranged. Alternatively, a photoresist or the like is coated. After the pattern exposure / development of the dry film 76, the ion milling of the low rail pattern, the peeling of the dry film, and the like, the rail pattern 62 of each slider is formed on the upper surface of the low 61 as shown in FIG. The formed is completed. Then, as shown in FIG. 10 (a), the row on which the rails are formed is adhered to the jig, the grooving process is performed for each slider, and the individual sliders are cut. Finally, each slider is removed from the jig. After peeling, as shown in FIG. 10B, individual magnetic head slider chips 63 on which rails are formed are completed. In any of these cases, adhesion or desorption is performed at a temperature that does not change the uniaxial anisotropy of the soft ferromagnetic thin film layer in the adhesion using the resin. Ruko Is necessary. These adhesion and desorption temperatures can generally be performed at 100 to 150 ° C. or less.
[0030]
Therefore, in the manufacture of the spin valve film head according to the present invention, no special post heat treatment process is required other than the heat treatment in the wafer stage, and the magnetic stability is disturbed by heating in the subsequent slider processing process. Nor.
[0031]
After each slider is peeled off from the jig, each slider has 400 to 800 kA in the track width direction of the slider at about room temperature (˜25 ° C.) for magnetization of the hard ferromagnetic thin film layer for longitudinal bias. A magnetic field of / m (5 to 10 kOe) is applied. The direction of the magnetic field is a direction orthogonal to the magnetization direction of the pinned layer pinned. It is known that pinned magnetization of the pinned layer starts to move only at a temperature higher than 150 ° C. in a magnetic field of about 400 to 800 kA / m. Therefore, the predetermined magnetization obtained by the heat treatment in the magnetic field performed at the wafer stage is used. The characteristics are not affected by this magnetization process.
[0032]
Note that the heat treatment process in the direction of the easy axis of the free layer can be performed only at the wafer stage, and can be performed at any stage of the slider final finished product stage or halfway to the final finished product. it can. For example, the final heat treatment may be performed after the final slider is completed. In this case, the final heat treatment is performed at 200 ° C. or lower so that the resist and other head elements are not adversely affected, and the free layer magnetization is The magnetic field applied in the direction of the easy axis (direction perpendicular to the pinned layer magnetization) is 80 kA / m (1 kOe) or less. As described above, the final heat treatment step for imparting uniaxial anisotropy to the soft magnetic thin film layer of the free layer can be performed at any step including a processing process after the wafer process. Moreover, this heat treatment is usually performed only once. That is, if the heat treatment process is performed at a temperature or lower that does not change the pinned magnetization of the soft ferromagnetic thin film layer pinned by the antiferromagnetic material, the characteristics are not deteriorated, and the heat treatment is performed under such conditions. Since there is no other after the regularization heat treatment process of the wafer, the anisotropy imparted to the magnetic thin film layer of the free layer in the subsequent process is correctly and reliably imparted, and the magnetization of the pinned layer remains stable. Is possible.
[0033]
Even in the assembly process of the magnetic head after the slider processing process, for example, in the wire bonding process or the resin molding process, heating to a temperature that changes the uniaxial anisotropy of the soft ferromagnetic layer is not performed. That is, it does not become 150 ° C. or higher.
[0034]
FIG. 11 is a graph showing the change characteristics of the GMR ratio with respect to the final heat treatment temperature of the PtMn spin valve MR film with respect to the external magnetic field. At 200 ° C., the GMR ratio is the original even when an external magnetic field of up to 80 kA / m (1 kOe) is applied. About 7.2% of the value of 95% is maintained. On the other hand, at 220 ° C., when an external magnetic field of about 30 kA / m is applied, the GMR ratio is lowered to 95% of the original value.
[0035]
It is desirable that the temperature of the regularized heat treatment for ensuring the characteristics of the pinned layer is at least a temperature at which the Hua value of the pinned soft magnetic thin film layer can ensure 90% or more of the peak value. FIG. 12 is a graph showing the relationship of the Hua value that can be secured with respect to the ordered heat treatment temperature in the PtMn film. From this graph, the Hua value is 90% or more of its peak value. This is a case where ordered heat treatment is performed at a temperature of ℃ or higher.
[0036]
FIG. 13 shows the BH loop characteristics of the soft ferromagnetic thin film layer (NiFe) of the free layer with respect to the difference in heat treatment temperature through which the layer passes. From this graph, the heat treatment temperature is 250 ° C. In the case of 270 ° C., the coercive force Hc in the BH loop is 80 A / m (1 Oe) or less and good soft magnetism, but at 300 ° C., the coercive force Hc suddenly increases to 320 A / m (4 Oe). I understand that. When the coercive force is increased in this way, the sensitivity is lowered and the reproduction waveform is distorted due to hysteresis. Therefore, the heat treatment temperature needs to be lower than 300 ° C. throughout the entire processing step of the head, and it is necessary to keep the temperature of the regularized heat treatment within that range. By doing so, the possibility of deterioration of the characteristics of each thin film layer of the spin valve is greatly reduced.
[0037]
However, if the final heat treatment is performed at a very low temperature, the uniaxial anisotropy of the soft ferromagnetic thin film layer of the free layer cannot be controlled in the correct direction (direction perpendicular to the pinning direction of the pinned layer). On the other hand, as the final heat treatment temperature increases and approaches the ordered heat treatment temperature, the dispersion of the pinned soft ferromagnetic thin film layer increases. FIG. 14 is a graph showing changes in Hua with respect to the magnetic field strength when an external magnetic field is applied in a direction perpendicular to the pinned layer at each temperature of 200 ° C. and 220 ° C. At 200 ° C., when a magnetic field exceeding 80 kA / m (1 kOe) is applied, Hua rapidly decreases. At 220 ° C., Hua decreases from around 50 kA / m. FIG. 15 shows a state in which the magnetization in the pin direction is inclined due to dispersion when the external magnetic field strength in the direction perpendicular to the pin layer magnetization direction is increased. At 200 ° C., an external magnetic field is 80 kA / m or more and a gradient due to dispersion of 15 degrees or more occurs, and at 220 ° C., it exceeds 15 degrees near 30 kA / m.
[0038]
According to the inventors' experiments, after the final heat treatment for the free layer, Rule The value of the shift amount Hua measured at room temperature of the BH loop of the soft ferromagnetic thin film layer pinned in the direction of the crystallization heat treatment magnetic field hardly changes when the MR rotational characteristics are measured at a low temperature. This is when the center of change falls within a dispersion slope of 20 degrees or less. If the final heat treatment is performed at a temperature or magnetic field intensity that makes the angle of dispersion inclination larger than that, the uniaxial anisotropy of the soft ferromagnetic thin film layer that should be pinned will not be controlled correctly, and therefore it will be manufactured. The defective ratio of the head becomes 30% or more. Therefore, it is desirable that the final heat treatment step be performed at a temperature and magnetic field strength such that the center of resistance change of the element is less than or equal to a dispersion slope of 20 degrees or less. Furthermore, from the aspect of actual characteristics, it is necessary to perform at the lowest temperature within a range in which the coercive force of the soft ferromagnetic thin film layer of the free layer is improved. Usually, the free layer of permalloy (81NiFe alloy) In this case, the temperature is preferably 180 to 200 ° C. The magnetic field strength during the final free layer thin film heat treatment is defined by the above conditions. When the free layer is permalloy, the magnetic field strength is 200 kC in a magnetic field of 80 kA / m (1 kOe) or less.
[0039]
【The invention's effect】
As described above, according to the present invention, in manufacturing the spin valve MR head, the pinned layer of the spin valve laminate has a blocking temperature sufficiently higher than the temperature at which the uniaxial anisotropy of the free layer starts to fluctuate. However, the film is preheated in the presence of oxygen and then regulated at a relatively low temperature of 300 ° C. or lower. Rule It has become possible to perform heat treatment. According to the observation of the inventor, this is considered to be because the size of the crystal of the magnetic material forming the pinned layer is just an appropriate size by the heat treatment in oxygen prior to the ordered heat treatment. In addition, first Rule The pinned layer fixed and pinned by the heat treatment is not affected by the magnetic characteristics under the subsequent process heating conditions until the process of assembling the magnetic head device using the spin valve magnetoresistive element head. Absent. The uniaxial anisotropy imparted to the ferromagnetic thin film layer is correctly and reliably controlled at the wafer stage, and the spin valve laminate is hardly deteriorated in the post-process.
[0040]
Also, regulations Rule After the crystallization heat treatment, in order to make the free layer uniaxial anisotropy that is easy to be magnetized in the track width direction, the pinning of the pinned layer is controlled so that the dispersion tilt angle falls within 20 degrees. Rule Since the heat treatment in a magnetic field is performed at a temperature equal to or lower than the heat treatment temperature, a read signal with less distortion can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing a main part of an element structure in a manufacturing process of a manufacturing method of a spin valve magnetoresistive head according to the present invention.
FIG. 2 is a perspective view schematically showing a main part of an element structure in a manufacturing process of a manufacturing method of a spin valve type magnetoresistive head according to the present invention.
FIG. 3 is a perspective view schematically showing a main part of an element structure in a manufacturing process of a method for manufacturing a spin valve magnetoresistive head according to the present invention.
FIG. 4 is a perspective view schematically showing a main part of an element structure in a manufacturing process of a method for manufacturing a spin valve magnetoresistive head according to the present invention.
FIG. 5 is a perspective view schematically showing a main part of an element structure in a manufacturing process of a manufacturing method of a spin valve magnetoresistive head according to the present invention.
FIG. 6 is a perspective view showing a processing step for a slider material wafer in the method of manufacturing a spin valve magnetoresistive head according to the present invention.
FIG. 7 is a perspective view showing a processing step of a slider material wafer in the method of manufacturing a spin valve magnetoresistive head according to the present invention.
FIG. 8 is a perspective view showing a slider row processing step in the method of manufacturing the spin valve magnetoresistive head according to the present invention.
FIG. 9 is a perspective view showing a slider row processing step in the method of manufacturing the spin valve magnetoresistive head according to the present invention.
FIG. 10 is a perspective view showing a slider row processing step in the method of manufacturing a spin valve magnetoresistive head according to the present invention.
FIG. 11 is a graph showing a change characteristic of an external magnetic field of a GMR ratio with respect to a final heat treatment temperature of a PtMn spin valve MR film used in the present invention.
FIG. 12 is a graph showing the relationship of the value of Hua that can be secured with respect to the ordered heat treatment temperature in the PtMn spin valve MR film used in the present invention.
FIG. 13 is a graph showing the BH loop characteristics of the free-layer soft ferromagnetic thin film layer (NiFe) used in the present invention.
FIG. 14 is a graph showing how the fixed layer used in the present invention changes with respect to the external magnetic field of Hua.
FIG. 15 is a graph showing how the inclination of the pinning magnetization of the pinned layer used in the present invention changes with respect to an external magnetic field.
FIG. 16 is a perspective view showing a schematic configuration of a spin valve element.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fixed layer, 2 ... Free layer, 3 ... Spacer layer, Is ... Sense current, 10 ... Spin valve film, 11 ... Antiferromagnetic material film, 20 ... Substrate, 21 ... Wafer, 22 ... Protective base film, 23 ... Lower shield film, 24 ... Gap film, 32 ... Hard magnet layer, 32a ... Hard ferromagnetic layer, 33 ... Lead layer, 33a ... Conductive metal film, 34 ... Lead cut resist, 40 ... Spin valve element, 40a ... SV stack Film: 41 ... SV cut resist, 42 ... Gap layer, 51 ... Seed layer, 52 ... Upper shield film (lower core), 53 ... Write gap, 54 ... Write pole, 55 ... Protective layer, 56 ... Write coil, 57 ... Insulator, 58 ... Upper core, 60 ... Slider material wafer, 61 ... Slider row, 62 ... Rail pattern, 63 ... Slider chip, 71 ... Cutting jig, 72 ... Adhesive resin, 3 ... cutting blade, 74 ... grinding polishing jig, 75 ... rail forming jig, 76 ... dry film.

Claims (6)

Preparing a substrate;
A spin valve laminate including a pinned layer having a PtMn film which is an antiferromagnetic film having a blocking temperature of 300 ° C. or higher on the substrate , a nonmagnetic high conductivity spacer layer, and a soft ferromagnetic film free layer. Forming step;
Heat treating the spin valve stack in an oxygen atmosphere;
Performing a regularized heat treatment at a temperature that imparts uniaxial anisotropy to the pinned layer while applying a magnetic field in a direction perpendicular to the track width direction to the spin valve laminate heat-treated in the oxygen atmosphere;
While applying a magnetic field in the track width direction to the spin valve laminate, the free layer has an easy axis of magnetization at a temperature and magnetic field strength at which the anisotropic dispersion angle of the aligned magnetic thin film layers is within 20 degrees of the alignment direction. Performing a heat treatment that imparts uniaxial anisotropy;
A method for manufacturing a spin-valve magnetoresistive head comprising: In the manufacturing method of the spin-valve magnetoresistive head according to claim 1,
The method in which the heat treatment in the oxygen atmosphere is a treatment in which the spin valve laminate is exposed to oxygen plasma at 300 ° C. or lower. In the manufacturing method of the spin-valve magnetoresistive head according to claim 1,
The step of performing a heat treatment for imparting uniaxial anisotropy to the free layer is at a temperature lower than the temperature for performing the ordered heat treatment, and the anisotropic dispersion angle of magnetization of the pinned layer is within 20 degrees from the direction before the heat treatment is performed. The method is carried out at a temperature in a range in which only a change in temperature is exhibited. In the manufacturing method of the spin-valve magnetoresistive head according to claim 1 ,
The method of performing the ordered heat treatment is performed at a temperature of 280 ° C. or lower. In the manufacturing method of the spin-valve magnetoresistive head according to claim 3 ,
The method of performing a heat treatment for imparting uniaxial anisotropy to the free layer is performed by applying a magnetic field in a track width direction. A method for manufacturing a spin valve magnetoresistive head according to claim 1, further comprising:
Bonding a hard ferromagnetic layer to both ends in the track width direction of the soft ferromagnetic film of the free layer;
Magnetizing the hard ferromagnetic layer so as to give a bias magnetization in the track width direction to the soft ferromagnetic film of the free layer.

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