JP2006344381A - Method of manufacturing thin film magnetic head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a MR head which is mounted on a magnetic disk apparatus of surface recording density 100 Gbit/in<SP>2</SP>and in which such accuracy is requested that accuracy of MR element height is ±0.02 mm or less and shape accuracy of floating plane is ±2 nm or less. <P>SOLUTION: The above problems can be solved by the following means. Finish polishing process is performed by slider shape, a resistance value of a resistance detecting element formed in the slider is detected in in-process, and when the detected resistance value or measure of MR element height converted from the detected resistance value reaches the prescribed value, polishing is stopped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thin film magnetic head in which a magnetoresistive element is formed, and more particularly to a structure and manufacturing method of a thin film magnetic head in which the element height and the air bearing surface shape of the magnetoresistive element are controlled with high accuracy.

  In recent years, the size and capacity of magnetic disk devices have been increasing, and small magnetic disk devices using 3.5-inch and 2.5-inch disks have become mainstream. Of the magnetic heads used in this small magnetic disk drive, a magnetic induction head whose reproduction output depends on the rotation speed of the disk cannot obtain a sufficient reproduction output because the number of rotations of the disk is small. On the other hand, in a magnetoresistive head using a magnetoresistive effect element whose resistance value changes according to the change of the magnetic field, a large reproduction output can be obtained because the reproduction output does not depend on the disk rotation speed. In addition, the magnetoresistive head is a magnetic head suitable for miniaturization and large capacity because it can obtain a higher reproduction output than the magnetic induction type magnetic head even for narrowing of the track due to higher density. It is considered.

  The magnetoresistive head includes an MR head using an MR (Magneto Resistive) element, a GMR head using a GMR (Giant Magneto Resistive) element, and a TMR head using a TMR (Tunneling Magneto Resistive) element. Here, the magnetic heads having the above three types of structures are collectively referred to as an MR head.

  By the way, in the MR head, in order to detect a change in the resistance value of the magnetoresistive element corresponding to the change in the magnetic field, the magnetoresistive effect is formed on the surface (hereinafter referred to as the air bearing surface) of the slider on which the MR head is mounted. The structure in which the element is exposed and used has the highest reproduction efficiency of the information signal recorded on the disc. In an exposed type MR head in which the magnetoresistive effect element is exposed on the air bearing surface, the end of the magnetoresistive effect element is exposed on the air bearing surface by polishing a part of the magnetoresistive effect element when processing the air bearing surface.

  The dimension of the magnetoresistive element in the direction orthogonal to the air bearing surface is called the magnetoresistive element height (MR element height), and the MR element height dimension is controlled by polishing. In this magnetoresistive head, since the reproduction output varies depending on the MR element height, variations in the MR element height appear in the form of fluctuations in the reproduction output of the magnetic head as they are.

  On the other hand, another factor of fluctuation in reproduction output is fluctuation in the flying height of the MR head. The MR head flies at a gap as small as a few tens of nanometers due to the dynamic pressure generated by the rotation of the magnetic disk, and there arises a problem that the reproduction output fluctuates when the flying height fluctuates. In order to stabilize the flying height, it is essential to suppress variation in the flying surface shape of the MR head that occurs in the polishing process and to always apply a constant dynamic pressure. Therefore, in order to suppress the reproduction output fluctuation of the magnetic head, it is necessary to control the height of the MR element with high accuracy and to form the air bearing surface with high accuracy in the polishing process.

As the MR element height is smaller, the performance of the magnetic head is improved, that is, the recorded information on the disk can be detected with high sensitivity. Therefore, the MR element height decreases year by year. At present, the general MR element height is 0.2 to 0.6 μm, and it is said that the magnetic disk device having a surface recording density of 100 Gbit / in ² or more is 0.1 μm or less. Accordingly, it is considered that the processing accuracy of the MR element height corresponding to these is required to be ± 0.02 μm (when the surface recording density is 100 Gbit / in ² or more).

In order to improve the surface recording density, it is necessary to reduce the area of one bit on the magnetic disk. For this purpose, it is effective to reduce the flying height of the magnetic head. In a magnetic disk device having a surface recording density of 100 Gbit / in ² or more, the flying height of the magnetic head may be 5 nm or less. To achieve this, the processing accuracy of the flying surface shape of the magnetic head must be ± 2 nm or less. It is considered to be required.

  As a method for polishing the MR element height with high accuracy, as described in Patent Documents 1 to 3, a measurement pattern (referred to as a resistance detection element) formed separately from the MR element in the element forming process is used. A method of converting the measured resistance value into the MR element height is generally used. The control method approximates the MR element height converted from the resistance values of several tens of resistance detection elements formed in the row bar by a quadratic curve or a quartic curve, and the slope component of this approximate curve and the quadratic curve. A method is used in which the load applied to the row bar during polishing is controlled so that the component and the swell component become small.

  On the other hand, with respect to increasing the accuracy of the air bearing surface shape, for example, as described in Patent Document 4, after the MR element height is controlled and polished, the row bar is polished via an elastic body such as urethane. In this state, a final polishing method is disclosed in which the air bearing surface of the MR head is pressed against a polishing surface plate, and the shape of the polishing surface plate is transferred to the air bearing surface with high accuracy.

JP-A-63-191570 Japanese Patent Laid-Open No. 10-49828 JP-A-10-208214 JP 2000-155921 A

The prior art described above has a drawback that an error occurs in the processing accuracy of the MR element height due to the following reasons. That is,
(1) An exposure mask formation error used when forming a magnetoresistive effect element and a resistance detection element on a substrate, and an exposure error in the exposure process.
(2) An error caused by a difference in polishing amount due to the position of the formed magnetoresistive effect element and the resistance detection element being separated.
(3) An error caused by an inclination component, a quadratic bending component, a waviness component, etc. in the MR element height distribution in the row bar that cannot be corrected in the air bearing surface polishing step.
(4) An error in converting the resistance value of the resistance detection element into the MR element height.
(5) Stop dimension error that occurs when the machining is terminated when the resistance value of the resistance detection element or the resistance value-converted MR element height reaches a predetermined value.
(6) Variation in processing amount that occurs when finishing polishing of the air bearing surface performed in the form of a row bar after polishing by controlling the MR element height.

  Due to the error factors described above, the height of the magnetoresistive element with the accuracy of ± 0.02 μm or less using the conventional technology is in spite of the great need to realize a small and large capacity magnetic disk device. It was extremely difficult. That is, as described in Patent Document 2 and Patent Document 3, a resistance detecting element for monitoring the polishing amount is provided adjacent to the magnetoresistive effect element. However, since polishing is performed in a row bar state, It was difficult to independently control the information obtained by the resistance detecting element and feed back to the polishing amount of the magnetoresistive effect element individually. Therefore, the element height of the magnetoresistive effect element actually obtained has a large variation, and it must be said that it is impossible to achieve an accuracy of ± 0.02 μm or less.

  On the other hand, with respect to the air bearing surface shape, the polishing pressure varies partially due to the influence of waviness and twist in the longitudinal direction of the row bar in order to perform finish polishing of the air bearing surface in the state of the row bar. It is difficult to achieve a shape accuracy of ± 2 nm or less.

An object of the present invention is to solve the drawbacks of the prior art, to provide a structure of a magnetic head capable of processing the MR element height and the air bearing surface shape with high accuracy, and a manufacturing method thereof, and to achieve a surface recording density of 100 Gbit / in ^2. An object of the present invention is to provide a magnetic head that satisfies both the above-described MR element height accuracy and air bearing surface shape accuracy.

  In the present invention, the first magnetoresistive effect element and the second magnetoresistive effect element are formed close to each other above the substrate on which the insulating film is formed, and the first magnetoresistive effect element and the second magnetoresistive effect element are formed. A thin film magnetic head was configured with one surface of the substrate orthogonal to the surface on which the effect element was formed as a slider surface facing the magnetic recording medium.

  In addition, the first magnetoresistive effect element and the second magnetoresistive effect element described above each include a first magnetoresistive effect film and a second magnetoresistive effect film formed by being sandwiched between electrodes, Further, the end portion of each magnetoresistive film is formed so as to be exposed on the slider surface. The two sets of electrodes and the magnetoresistive film were formed so as to have the same geometric shape.

  According to the present invention, the first magnetoresistive effect element includes the first magnetoresistive effect film formed by being sandwiched between the lower shield film and the upper shield film, and is laminated on the substrate. The second magnetoresistive film constituting the second magnetoresistive element is formed in the plane on which the magnetoresistive film is formed.

  In the present invention, a step of forming a first magnetoresistive element and a second magnetoresistive element above the substrate on which the insulating film is formed, the first magnetoresistive element and the second magnetoresistive element. A step of cutting the slider so as to include an effect element, and a step of polishing the surface perpendicular to the first magnetoresistive effect element and the second magnetoresistive effect element by mounting the slider on a polishing apparatus. Therefore, polishing was performed for each slider described above.

  At this time, the slider uses the first magnetoresistive element as a means for reproducing a magnetic signal from the magnetic recording medium and the second magnetoresistive element as a means for measuring the polishing amount of the slider surface. When the surface is polished, the resistance value of the second magnetoresistance effect element is detected, and the height value of the second magnetoresistance effect element converted from the resistance value or the resistance value reaches a predetermined value Then, the polishing process was finished to manufacture a thin film magnetic head.

  In addition, at least one slider is attached to the polishing apparatus, the resistance value of the second magnetoresistance effect element formed for each slider is detected, and the resistance value or the second magnetoresistance effect converted from the resistance value is detected. When the height dimension of the element reaches a predetermined value, the polishing of the slider is finished.

  Furthermore, by attaching a slider to the polishing device via an elastic body and finishing polishing the air bearing surface in units of sliders, the influence of wobbling and twisting on the air bearing surface on the polishing accuracy of the air bearing surface is eliminated. The platen shape was transferred to the air bearing surface of each slider.

  As described above, when one of the two magnetoresistive elements provided for each slider is used for measuring the amount of polishing of the slider, the resistance value or the height of the magnetoresistive element converted from the resistance value is reached. In addition, by finishing the polishing of the slider, it is possible to realize a thin film magnetic head having the height of the magnetoresistive element controlled with high accuracy. At the same time, it is possible to realize a thin-film magnetic head having a flying surface shape formed with high precision by mounting the slider on the polishing device via an elastic body and finishing polishing the flying surface in units of sliders. is there.

  First, an outline of the magnetic disk device will be described. FIG. 1 is a diagram for explaining the arrangement of the magnetic head 1 and the disk 2. The magnetic head 1 includes a slider 3 and a magnetoresistive element 5 formed on the slider 3 orthogonal to the slider surface 4. In a CSS (Contact Start Stop) type magnetic disk device, the end of the magnetic head 1, more precisely the magnetoresistive element 5, is moved from the surface of the disk 2 by utilizing the dynamic pressure generated by the rotation of the disk 2 that is a magnetic recording medium. A small amount is levitated and information is recorded on or reproduced from the disk 2. At this time, the distance between the surface of the disk 2 and the magnetoresistive element 5 is defined as the flying height h. The smaller the flying height h, the higher the recording or reproducing efficiency.

Next, the magnetic head 1 will be described with reference to the structural diagram of FIG. In this figure, for example, a well-known thin film formation process such as sputtering is performed on the surface of a substrate 6 made of a non-magnetic material such as Al ₂ O ₃ —TiC or SiC, on the surface of an inductive magnetic transducer 10 and a magnetoresistive element 5. , A photolithographic process, an etching process, or the like. This is cut into strips to form a row bar 7 having a plurality of magnetic heads.

  Furthermore, the magnetic head 1 is completed by cutting the row bar 7. At this time, a part of the substrate 6 cut so as to include the inductive magnetic transducer 10 and the magnetoresistive element 5 is the slider 3, and the inductive magnetic transducer 10 and the magnetoresistive element 5 are formed. One surface of the slider 3 that is orthogonal to the curved surface functions as the air bearing surface 4.

  FIG. 3 is a perspective view showing the structure of the element portion of the magnetic head 1 (inductive magnetic transducer 10 and magnetic low-efficiency element 5). The inductive magnetic recording element 10 includes a coil 8, an upper magnetic film 9, and an upper shield film 11, and the end of the upper magnetic film 9 is disposed so as to be substantially flush with the air bearing surface 4 of the slider 3. Then, information is recorded on the disk 2 using the exposed portion.

  A magnetoresistive element 5 is disposed in the vicinity of the inductive magnetic recording element 10, and an electrode 13 is formed so as to sandwich the magnetoresistive film 12. The magnetoresistive effect film 12 and the electrode 13 are sandwiched between the upper shield film 11 and the lower shield film 14 in order to reduce noise when reproducing information recorded on the disk 2 using the magnetoresistive effect element 5. It has a structure.

  Here, the height from the end of the magnetoresistive film 12 to the air bearing surface in a direction substantially perpendicular to the air bearing surface 4 of the slider 3, that is, the height of the magnetoresistive film 12 is called the MR element height. The MR element height and the shape of the air bearing surface 4 are formed by polishing, and the polishing accuracy dominates the MR element height accuracy and the air bearing surface shape accuracy.

By the way, recording / reproducing of the magnetic disk apparatus using the magnetic head 1 is performed as follows.
(1) Necessary information is recorded on the disk 2 by magnetizing the surface of the disk 2 using the coil 8 and the upper magnetic film 9.
(2) When the surface of the magnetized disk 2 and the magnetic head 1 are relatively moved, the resistance value of the magnetoresistive effect film 12 changes depending on the polarities of the magnetic poles S and N written on the disk 2. By detecting this change in resistance value, the information written on the surface of the disk 2 is reproduced.

  As described above, when the magnetic head 1 having the magnetoresistive effect element 5 is used, the MR element height, that is, from the end of the magnetoresistive effect film 12 positioned substantially flush with the flying surface 4 of the slider 3, It is extremely important to polish the height dimension in a direction substantially perpendicular to the air bearing surface 4 with high accuracy. Therefore, a method for polishing with high precision while controlling the height of the MR element will be described below.

  FIG. 4 is an external view of a generally well-known row bar 7. As an example, the row bar 7 has a shape in which several tens of magnetic heads 1 are connected, and when separated into individual magnetic heads 1, the floating surface 4 that becomes the slider 3 shown in FIG. The resistance effect element 5 is polished in the state of the row bar 7. At this time, as illustrated in FIG. 5, a resistance detecting element 15 for detecting the MR element height at the time of polishing is generally provided at a cutting portion provided between the individual magnetic heads 1 in the row bar 7. Is provided.

  Then, when a part of the resistance detection element 15 is removed by polishing of the air bearing surface 4, a change in the resistance value is detected, and the detected resistance value is converted into the MR element height, whereby the row bar 7. The MR element height distribution in the inside is monitored. At this time, the polishing load applied to the row bar 7 is adjusted using the resistance values detected by the plurality of resistance detecting elements 15 so that the MR element height distribution is uniform.

  The size of the current mainstream magnetic head 1 is called a pico slider, and the outer dimensions of the magnetic head 1 are a width of 1.2 mm, a length of 1.0 mm, and a height of 0.3 mm. The state of the row bar 7 illustrated in FIG. Then, the width (b) is 1.2 mm, the length (L) is 40 to 80 mm, and the height (t) is 0.30 to 0.33 mm. The reason why the length of the row bar 7 is very long compared to other dimensions is that by increasing the length of the row bar 7, the number of magnetic heads 1 included in one row bar 7 can be increased. This is because the productivity of the magnetic head 1 can be improved.

  However, when polishing is performed in the state of the row bar 7 as a conventional technique, the rigidity of the row bar 7 decreases as the length increases, and a second-order bending component and a higher-order curve component higher than the cubic curve are contained in the row bar 7. (Called a swell component) is likely to occur. The secondary bending component described above can be corrected relatively easily by detecting the resistance value of the resistance detecting element 15 provided in the row bar 7 and appropriately adjusting the load applied to the row bar 7 based on the detected value. Although it is possible, it is difficult to correct the waviness component.

FIG. 6 shows the relationship between the areal recording density, track width, MR element height, and processing tolerance. The track width is the dimension in the width direction of the MR element shown in FIG. As shown in FIG. 6, the track width and the element height are reduced in size as the surface recording density is improved. While the track width depends on the lithography exposure accuracy, the element height is 0.8 times the track width, and the processing tolerance of the element height is generally required to be 1/4 of the element height. . As shown in the figure, in order to realize the surface recording density of 100 Gbit / in ² , the processing tolerance of the element height needs to be ± 0.024 μm or less.

  However, in the conventional processing method, the factors that cause variations in the MR element height of each completed magnetic head 1 have been described in the section of the problem in the above-described invention, but the factors (1) to (3) and (6) are particularly important. This occurs when the air bearing surface is polished in the state of the row bar 7, and since the undulation component in the row bar 7 cannot be corrected sufficiently, a processing tolerance of element height of ± 0.024 μm is achieved. It is difficult.

  Next, a method for forming the air bearing surface shape will be described below. FIG. 7 shows a conceptual diagram of the air bearing surface shape. As shown in the figure, the warp in the longitudinal direction of the magnetic head is called a crown, and the warp in the short direction of the magnetic head is called a camber. The measurement of these parameters uses an optical interference type shape measuring instrument represented by NEW VIEW 200 of ZYGO. The crown approximates the shape of the magnetic head air bearing surface in the longitudinal direction as a cylinder and uses the amount of warpage. On the other hand, the camber approximates the shape of the head air bearing surface in the short direction as a cylinder and sets the amount of warpage. It is the positive crown and the positive camber that warp the convex shape.

  In the conventional method of forming the air bearing surface shape, after the above-described element height control polishing process, a row bar is attached to a polishing jig via an elastic body such as urethane, and the air bearing surface is used as a polishing surface plate in that state. It is formed by a finish polishing method that presses and transfers the shape of the polishing surface plate to the air bearing surface. By using an elastic body, compared to the case where the row bar is fixed with wax or the like, there is no deterioration in shape accuracy due to adhesive distortion, and the waviness in the longitudinal direction of the row bar can be corrected, and the surface plate shape is accurately transferred. It becomes possible. However, as with the control polishing of the element height, it is difficult to correct higher-order waviness in the longitudinal direction of the row bar with the elastic body, and distribution of the polishing pressure occurs in the row bar due to the influence of the waviness. As a result, it is difficult to form the air bearing surface with high accuracy.

As described above, the processing accuracy of the crown and the camber affects the fluctuation of the flying height of the magnetic head. As shown in FIG. 8, the flying height of the magnetic head decreases with the improvement of the surface recording density, and in order to realize low flying height, it is necessary to increase the processing accuracy of the crown and the camber. As shown in the figure, in order to achieve a surface recording density of 100 Gbit / in ² , the shape accuracy of the crown and camber, which are the air bearing surface shapes, must be ± 2 nm or less.

Embodiments of the present invention will be specifically described below with reference to the drawings.
When the air bearing surface 4 is polished in the state of the row bar shown in FIG. 4 and the height of the MR element is simultaneously controlled, the above-described variation specific to the shape of the row bar occurs. Therefore, in the present invention, the polishing is performed in the state of the slider in order to eliminate the variation factor. That is, the resistance value is detected using a resistance detection element provided for each slider, and polishing is performed while the result is sequentially fed back to the polishing conditions.

  FIG. 9 is a perspective view of a magnetic head according to an embodiment of the present invention, and FIG. 10 is a schematic cross-sectional view of the magnetic head viewed from the air bearing surface with the end of the magnetoresistive element exposed to the air bearing surface. Show. The magnetic head described above is formed by the same method as that shown in FIGS. 2 to 5 above, but the difference from the conventional case is as follows. That is, the first magnetoresistive effect element 101 and the second magnetoresistive effect element 102 are formed close to the slider 3 separated from the row bar. The first magnetoresistive effect element 101 and the second magnetoresistive effect element 201 are formed so as to be in contact with and sandwiched by a part of the first magnetoresistive effect film 102 and the second magnetoresistive effect film 202, respectively. The first electrode 103 and the second electrode 203 are stacked above the substrate 3 (slider 3 after cutting) having the insulating film 301.

  The first magnetoresistive effect film 102 and the second magnetoresistive effect film 202 and the first electrode 103 and the second electrode 203 are geometrically identical in shape and formed using the same material. The second magnetoresistive film 202 is formed in the same plane as the first magnetoresistive film 102. Further, the first magnetoresistive element 101 includes a lower shield film 104 and an upper shield film 105 that are formed so as to sandwich the first magnetoresistive film 102 and the first electrode 103. It is desirable that the distance d between the first magnetoresistive element 101 and the second magnetoresistive element 201 be as small as possible in consideration of the dimensional tolerance of the photomask, errors in the photoprocess, and the like.

  The inductive magnetic transducer 10 for recording information on the disk 2 is formed above the first magnetoresistive element 101 via the upper shield film 105, and its structure and formation method are the same as in the prior art. Yes, omitted here.

Next, the polishing process of the flying surface of the slider will be described. FIG. 11 shows a machining process flow in this embodiment as compared with the prior art. That is,
(1) The substrate 6 provided with the first magnetoresistive effect element 101, the second magnetoresistive effect element 201, and the inductive magnetic transducer 10 is cut into the shape of the row bar 7.
(2) The surface of the substrate 6 orthogonal to the surface on which the first magnetoresistive effect element 101 and the second magnetoresistive effect element 201 are formed is subjected to rough polishing using a method called double-sided lapping, and MR The element height is processed into a predetermined dimension.
(3) Further, the air bearing surface 4 of the slider 3 is polished in this state to bring the MR element height close to a predetermined value. That is, if the MR element height of the completed magnetic head is Hf, the target value Hb of the polishing process in this step is about Hf + 0.03 to 0.15 μm. The process up to this step is the same as in the prior art.
(4) The row bar 7 is cut so that the first magnetoresistive effect element 101 and the second magnetoresistive effect element 201 are included in each slider.
(5) A slider is attached to the polishing apparatus, and the air bearing surface 4 is polished while detecting the resistance value of the second magnetoresistive effect element 201 for each slider and feeding back the result to the polishing apparatus. Alternatively, polishing is performed until the MR element height converted from the resistance value becomes Hf.
(6) Next, in this embodiment, a levitating rail is formed on the surface of the air bearing surface 4 by using a well-known ion milling method or sputtering method.

  On the other hand, in the prior art, (3) the air bearing surface is processed in the state of a row bar, and then finish polishing until the resistance value of the second magnetoresistance effect element 201 or the converted MR element height becomes Hf. Is done. However, since polishing is performed in the state of a row bar in which several tens of magnetoresistive elements are connected, even if the resistance value of the second magnetoresistive element is detected and the result is fed back to the polishing apparatus, It is impossible to apply a necessary polishing load only to the slider portion. Therefore, in this case, it is unavoidable that extremely large variations occur with respect to the target MR element height Hf.

Next, a highly accurate polishing method for the air bearing surface in the step (5) described above will be described with reference to FIGS. FIG. 12 is a conceptual diagram of the polishing apparatus used in this example. FIG. 13 is a conceptual diagram when the slider 3 having the first magnetoresistive effect element 101 and the second magnetoresistive effect element 201 is attached to the polishing apparatus. In these drawings, an adhesive elastic body 301 such as polyurethane is attached to the back surface of the slider 3 (the surface on which the first magnetoresistive film 103 and the second magnetoresistive film 203 are not exposed). Then, it is fixed to the upper and lower cylinders 303 of the polishing jig 302.
As shown in FIG. 13, for example, a film-like circuit board 304 is attached to the upper and lower cylinders 303, and a terminal 305 of the film-like circuit board 304 and a terminal of the second magnetoresistive effect element 201 shown in FIG. 6. 204 can be connected with a wire 309 using, for example, a wire bonding method, and the resistance value of the second magnetoresistive element 201 can be detected during polishing.

  In the embodiment shown in FIG. 12, a polishing jig 302 to which a plurality of sliders 3 are fixed is attached to a lapping apparatus, and is arranged so that the air bearing surface 4 of the slider 3 and the polishing surface plate 306 face each other. Before polishing, the actuator 307 and the upper and lower cylinders 303 are separated from each other, and the upper and lower cylinders 303 are pushed up by, for example, a coil spring 308, so that the slider surface 4 and the polishing surface plate 306 are not in contact with each other. Is placed in.

  FIG. 14 is a diagram showing a state when the slider 3 is being polished. By applying a load F to the upper and lower cylinders 303 using the actuator 24, the air bearing surface 4 of the slider 3 and the polishing surface plate 306. Make contact with the surface. In this state, while dripping an oily or water-soluble polishing liquid (not shown) that does not contain abrasive grains onto the polishing surface plate 306, the polishing surface plate 306 is rotated within a range of 0.1 to 20 r / min, for example. The surface of the air bearing surface 4 is polished by reciprocating the polishing jig 302 in the diameter direction or normal direction of the polishing surface plate 306 within a range of 1 to 300 mm / s, for example. For the surface of the polishing surface plate 306, for example, a fixed abrasive surface plate in which diamond abrasive grains having an average particle size of 1/2 to 1/20 μm are embedded in the surface of the surface plate outside the machine is used.

While the polishing is performed, the resistance value of the second magnetoresistive film 202 is measured according to an appropriate or determined schedule using the second magnetoresistive element 201 provided on the slider 3, The result is fed back to the actuator 307. Then, as illustrated in FIG. 15, when the resistance value measured using the second magnetoresistive effect element 202 or the MR element height converted from the resistance value reaches a predetermined value, a polishing load is applied to the slider 4. When the actuator 307 that has been applied is operated in the opposite manner and the load applied to the upper and lower cylinders 302 is zero, the upper and lower cylinders 302 are pushed up by the restoring force of the coil spring 308. (In FIG. 12, the right end and the fourth polishing jig correspond)
In this way, the magnetic head 1 having a predetermined value of the MR element height converted from the resistance value or resistance value of the second magnetoresistive effect element 202 formed in the slider 3 is completed. As shown in the present embodiment in FIG. 15, a plurality of sliders 3 are polished together, and the processing is sequentially completed from the sliders 3 whose MR element height has reached a predetermined value. The slider 3 whose MR element height does not reach the predetermined value continues to be polished. When polishing of all the sliders 3 attached to the polishing jig 302 is completed, the rotation of the polishing surface plate 306 and the reciprocating motion of the polishing jig 302 are stopped, and the processing is completed.

As described above, the polishing method described in this embodiment has the following effects, and can process the MR element height and the air bearing surface shape with extremely high accuracy.
(1) Since polishing is performed for each slider and using the characteristics of the magnetoresistive effect element provided on each slider, it is possible to reduce variations in processing amount due to polishing processing for each row bar in the prior art. I can do it.
(2) Since the polishing process is performed for each slider, the process can be controlled independently.
(3) By forming the first magnetoresistive element (for recording / reproducing) and the second magnetoresistive element (for polishing process monitoring) close to each other in the slider, processing caused by the distance between them. Variation in quantity can be reduced.
(4) By using a magnetoresistive effect film and electrodes constituting the magnetoresistive effect element for recording / reproducing and the same member and the same shape of the polishing element, polishing of the magnetoresistive effect element for recording / reproducing is substantially performed. Processing becomes possible.
(5) Since the magnetoresistive effect element for polishing process excludes the shield film, it is possible to reduce the noise caused by the scratch generated during the polishing process, and the resistance value can be measured with high sensitivity.

That is, when a shield film is present, or when the amount of polishing processing is measured using a magnetoresistive effect element for recording and reproduction, the distance between the shield film provided between the magnetoresistive film and the electrode is at most 80 to 100 nm. Therefore, the resistance value to be detected by a short circuit between the shield film and the electrode due to scratching during polishing is smaller than the original resistance value, and is measured. As a result, accurate polishing cannot be performed, and a large variation in MR element height occurs.
(6) Since each slider and each slider is attached to a polishing apparatus via an elastic body and polishing is performed, variation in shape of the air bearing surface due to row bar twisting and warping in the prior art can be reduced. .

Next, the results of polishing processing based on this example will be described.
FIG. 16 shows the result of processing and polishing performed while detecting the resistance value of the second magnetoresistive element 201 provided for each slider, and measuring the resistance value of the first magnetoresistive element 101 after the end of polishing. . As a result, it is clear that the resistance values of the first magnetoresistive effect element 101 and the second magnetoresistive effect element 201 formed in the slider have a very good correlation.

  This is because the first magnetoresistive element is processed and polished while monitoring the resistance value of the second magnetoresistive element 201 provided close to the first magnetoresistive element 101 in the slider. That is, it means that the resistance value or MR element height of the magnetoresistive effect element in the actual magnetic head can be processed with high accuracy.

  17 (a) and 17 (b) show the MR element height (resistance conversion value) and MR element resistance value of the magnetic head after the air bearing surface is polished in the state of a row bar as in the prior art, and then cut into a slider. FIG. FIGS. 18A and 18B are distribution diagrams of the MR element height (resistance conversion value) and the resistance value of the MR element when each slider is polished using this embodiment. The resistance value of the MR element was measured using a ΔV-H apparatus manufactured by Macro. The MR element height is a value obtained by converting the measured resistance value into the MR element height.

  As is clear from this result, the MR element height in the prior art has an average value of 0.26 μm, a maximum value of 0.34 μm, a minimum value of 0.17 μm, and a variation (3σ value) of 0.091 μm. The MR element height in the example has an average value of 0.25 μm, a maximum value of 0.27 μm, a minimum value of 0.23 μm, and a variation (3σ value) of 0.022 μm. Further, the resistance value of the MR element in the prior art is an average value of 41.3Ω, a maximum value of 62.3Ω, a minimum value of 31.0Ω, and a variation (3σ value) of 15.4Ω. The resistance value is an average value of 42.1Ω, a maximum value of 45.7Ω, a minimum value of 38.9Ω, and a variation (3σ value) of 3.7Ω.

In other words, by using the structure of the magnetic head described in this embodiment (see FIG. 6) and the polishing method for each slider (see FIG. 12), a magnetic disk device with a recording surface density of 100 Gbit / in ² can be realized. This shows that it is possible to manufacture a magnetic head having an indispensable MR element height accuracy of ± 0.024 μm.

  The magnetic head polished by using this embodiment is randomly extracted, and the relationship between the sampling number, the variation in the height of the GMR element (3σ), the variation in the resistance value (3σ), and the average value is shown. It shows to Fig.19 (a), (b). When the magnetic head manufactured by the above method is randomly extracted in the range of several to 100, if the number of extraction is 10 or more, the variation (3σ) in the element height of the GMR element becomes 0.026 μm, and the resistance The ratio between the value variation (3σ) and the average resistance value is approximately 0.11.

  From this result, 10 magnetic heads were randomly extracted, and the GMR element height variation (3σ) was 0.026 μm or less, or the ratio between the resistance variation (3σ) and the average value was approximately 0.11. If so, it can be said that the distribution is the same as in the case of using the present embodiment shown in FIG. If the conversion formula for calculating the GMR element height from the resistance value of the GMR element is unknown, the GMR element portion is processed in the element height direction by a focused ion beam processing apparatus (FIB), and the GMR element from the cross section is processed. The element height may be obtained.

  FIG. 20A shows the relationship between the reproduction output of the magnetic head and the resistance value of the GMR element in the prior art, and FIG. 20B shows the relationship in this embodiment. As a result, in the prior art, as shown in FIG. 17A, the MR element height varies greatly, and as a result, the resistance value and the reproduction output of the GMR element are distributed over a wide range. On the other hand, in this embodiment, since the variation in the MR element height can be extremely reduced as shown in FIG. 19B, the variation in the resistance value and reproduction output of the GMR element can be reduced. Thus, it is no exaggeration to say that it is possible to provide a magnetic head having one of the important characteristics as a magnetic head and having a stable reproduction output and high reliability.

  FIGS. 21 (a) and 21 (b) show the distribution of the crown and camber, which are the shape of the air bearing surface when the finish of the air bearing surface is finished in the state of the row bar, which is a conventional processing method. FIGS. 22A and 22B show the distribution of crowns and cambers, which are the air bearing surfaces when the slider is polished for each slider using this embodiment. The crown and camber were measured by NEW VIEW200, a light interference type shape measuring instrument manufactured by ZYGO, and the measurement length was 1.1 mm for the crown and 0.9 mm for the camber.

  As is clear from this result, the crown in the prior art has an average value of 2.9 nm, a maximum value of 9.9 nm, a minimum value of −1.8 nm, and a variation (3σ value) of 2.3 nm, and the camber has an average value of −0. 76 nm, maximum value 3.7 nm, minimum value −4.1 nm, variation (3σ value) 3.0 nm, whereas crown in this example has an average value 1.8 nm, maximum value 3.0 nm, minimum value The camber has an average value of −0.22 nm, a maximum value of 0.9 nm, a minimum value of −1.1 nm, and a variation (3σ value) of 1.0 nm.

In other words, by using the structure of the magnetic head described in this embodiment (see FIG. 9) and the polishing method for each slider (see FIG. 15), a magnetic disk device with a recording surface density of 100 Gbit / in ² can be realized. This shows that it is possible to manufacture a magnetic head having an indispensable air bearing surface shape accuracy of ± 2 nm.

  23A and 23B show the relationship between the sampling number, the crown variation (3σ), and the camber variation (3σ), which are randomly extracted from the magnetic head polished by using this embodiment. When 30 magnetic heads are randomly extracted, the crown variation (3σ) is 1.4 nm, and the camber variation (3σ) is 1.0 nm. From this result, if 30 magnetic heads are extracted at random, and the crown (3σ) is 1.4 nm or less and the camber variation (3σ) is 1.0 nm or less, the book shown in FIG. It can be said that the distribution is the same as in the case of using the embodiment.

  MR element height and flying height are controlled with high precision by forming magnetoresistive effect elements for recording / reproducing and for detecting the amount of polishing in the slider, and performing finish polishing for each slider while monitoring the amount of processing. A magnetic head having a surface shape can be realized.

FIG. 3 is an arrangement diagram showing a relationship between a magnetic head and a disk. It is a conceptual diagram for demonstrating the manufacturing process of a magnetic head. It is a perspective view for demonstrating the structure of a magnetic head. It is the schematic of a row bar which is in the state where a magnetic head continued. It is an expansion schematic for demonstrating a row bar. It is a figure showing the relationship between the surface recording density of a magnetic disc unit, and GMR element height accuracy. It is a conceptual diagram of the air bearing surface shape (crown, camber) of a magnetic head. It is a figure showing the relationship between the surface recording density of a magnetic disc apparatus, and the shape precision of a magnetic head air bearing surface. It is a perspective view for demonstrating the structure of the magnetic head which is a present Example. 1 is a cross-sectional structure diagram of a magnetic head according to an embodiment. It is the polishing process flow in a prior art and a present Example. It is the apparatus schematic for performing the grinding | polishing process for every slider which is a present Example (before a process). It is an enlarged view of the slider attachment part of a processing apparatus. It is the apparatus schematic for performing the grinding | polishing process for every slider which is a present Example (during processing). It is the apparatus schematic for performing the grinding | polishing process for every slider which is a present Example (process completion | finish). It is a resistance value correlation diagram in the 1st and 2nd magnetoresistive effect element. It is a distribution map of GMR element height (resistance value conversion) and GMR element resistance value in the prior art. It is a distribution map of the GMR element height (resistance value conversion) and GMR element resistance value in a present Example. It is a figure showing the relationship between the sampling number of a magnetic head, GMR element height (resistance value conversion), and dispersion | variation (3 (sigma)) of GMR element resistance value. It is a figure showing the relationship between the resistance value of the GMR element and reproduction output in a present Example. It is a distribution map of the crown and camber in the prior art. It is a distribution map of a crown and a camber in a present Example. It is a figure showing the relationship between the sampling number of a magnetic head, and the dispersion | variation (3 (sigma)) of a crown and a camber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Magnetic head, 2 ... Disk, 3 ... Slider, 4 ... Slider surface, 5 ... Magnetoresistive element, 6 ... Substrate, 7 ... Row bar, 8 ... Coil, 9 ... Upper magnetic film, 10 ... Induction type magnetic transducer 11 ... Upper shield film, 12 ... Magnetoresistive film, 13 ... Electrode, 14 ... Lower shield film, 15 ... Resistance sensing element, 101 ... First magnetoresistive element, 102 ... First magnetoresistive film, DESCRIPTION OF SYMBOLS 103 ... 1st electrode, 104 ... Lower shield film, 105 ... Upper shield film, 201 ... 2nd magnetoresistive effect element, 202 ... 2nd magnetoresistive effect film, 203 ... 2nd electrode, 204 ... Resistance detection 205 ... Terminal of magnetic conversion element 301 ... Surface adhesive elastic body 302 ... Polishing jig 303 ... Upper cylinder, 304 ... Film circuit board, 305 ... Terminal, 306 ... Polishing surface plate, 307 ... Actu Over motor, 308 ... spring 309 ... wire bonding wire

Claims (4)

  After forming an insulating film on the substrate, a first magnetoresistive element for reproducing a magnetic signal from the magnetic recording medium and a second magnetoresistive element for measuring the amount of polishing processing are formed on the insulating film. Are formed adjacent to each other, a slider splitting step in which the first magnetoresistive effect element and the second magnetoresistive effect element are paired and cut into one slider, and the first magnetism A polishing step of polishing the surface of the substrate perpendicular to the surface on which the resistance effect element and the second magnetoresistance effect element are formed to form an air bearing surface, the polishing step comprising the second magnetic A resistance value of a resistance effect element is measured, and the polishing of the air bearing surface is finished for each slider when the second magnetoresistance effect element reaches a predetermined resistance value. Method.   In the element formation step, the first magnetoresistive element is stacked so as to sandwich a first magnetoresistive film and a pair of first electrodes that are in contact at both ends of the first magnetoresistive film. A pair of shield films are disposed on the insulating film, and the second magnetoresistive element is in contact with the second magnetoresistive film and both ends of the second magnetoresistive film. Only the second electrode is disposed on the insulating film, and the first magnetoresistive film, the second magnetoresistive film, and the first electrode and the second electrode are respectively geometrical. The method of manufacturing a magnetic head according to claim 1, wherein the magnetic heads are formed using the same material having the same shape.   3. The element forming step, wherein the first magnetoresistive film and the second magnetoresistive film are formed on the insulating film in the same plane. A manufacturing method of the magnetic head. The slider cut in the dividing step is mounted on a polishing jig that is individually movable in a direction perpendicular to the air bearing surface, and the polishing amount of the slider is used as the resistance value of the second magnetoresistance effect element. The method of manufacturing a magnetic head according to claim 1, wherein the magnetic head is controlled.

Images