JP2006331562A - Manufacturing method of thin film magnetic head, and thin film magnetic head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that correcting of a size by inclination work becomes difficult depending on the case since the height of an element can be measured precisely only when the height of the element becomes close to a design size sufficiently in a polishing work process though a method of inclining a slider in the case of floating surface polishing in order to reduce variance of a throat height of a main magnetic pole. <P>SOLUTION: The floating surface polishing work is carried out by the following procedure. (1) The slider is inclined so as to make an element side a little deeper, and the element is worked to a height where the element can be measured with sufficient sensitivity. (2) The height of a reproduction element and a recording element at the time are measured, and a slider inclination for correcting misregistration is calculated from an error from sizes on design of each. (3) In order that both of the reproduction element and the recording element may have sizes of a final design, the elements are polished while varying the inclination gradually. (4)When bothe of the reproduction element and the recording element come to have the proper height, the working is completed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a thin film magnetic head and a thin film magnetic head mounted on a magnetic recording apparatus such as a magnetic disk device, and more particularly to a method for manufacturing a perpendicular magnetic recording head and a perpendicular magnetic recording head.

  In recent years, the recording density of magnetic disk devices has been growing at an annual rate of several tens of percent. However, in the conventional in-plane recording method, magnetic data is arranged horizontally with respect to the disk surface, so the magnetic poles repel each other. Densification is difficult. Even if the film thickness of the recording medium is reduced and the magnetic poles are prevented from being repelled and the density can be increased, the problem of thermal disturbance in which the recording magnetization becomes unstable due to thermal energy at room temperature is inevitable. Therefore, it is considered difficult to achieve a recording density exceeding about 15.5 Gbit / square centimeter (100 Gbit / square inch) with the in-plane recording technology.

  On the other hand, the perpendicular recording method differs from the in-plane recording method in that the demagnetizing field acting between adjacent bits decreases as the linear recording density increases, and the recording magnetization is kept stable. Is effective as a technique for realizing ultra high density recording. Perpendicular magnetic recording applies information to a magnetic layer in a direction perpendicular to the disk surface by applying a magnetic field to the recording layer sandwiched between the backing soft magnetic layer of a double-layer recording medium and a single pole head. This is a magnetic recording method for recording. In order to obtain a large recording magnetic field, it is necessary to make the throat height of the main pole of the perpendicular magnetic recording head as short as possible. However, if the height is too short, the writing of the recording is blurred. If the height is too long, erasure after recording due to residual magnetization occurs.

  In the in-plane recording method, the accuracy of the magnetic pole height of the recording element is not so strict, but in the perpendicular recording method, a very high accuracy with respect to the throat height is required for the above reason. On the other hand, the height of the reproducing element is not different from that in the in-plane recording method even in the perpendicular recording method, and high dimensional accuracy is required, and this accuracy must be satisfied at the same time.

  In Patent Document 1, in order to process the height of the magnetoresistive effect (MR) element of the magnetic head slider with an accuracy of ± 0.020 μm or less, a plurality of vertical axes that are vertically displaced by two leaf springs, A set of a plurality of load application mechanisms that individually apply a polishing load to the vertical axis via an adapter is arranged and fixed at a predetermined pitch on the polishing head positioning mechanism, and an adhesive elastic body is provided at the lower end of each vertical axis The magnetic head slider is individually held and pressed against the polishing platen, and the polishing load is individually controlled while detecting the resistance value of the MR element of each magnetic head slider with the resistance detection circuit board in-process during polishing. A method is disclosed.

JP 2004-71016 A

  The height of the main pole of the recording element of the thin film magnetic head and the height of the reproducing element are finally formed in the polishing process of the air bearing surface of the magnetic head slider, but the throat height dimension of the main pole of the recording element (1) Recording element and reproducing element separated by several μm in the film formation direction, exposure accuracy when forming both elements, and (2) air bearing surface with respect to the film surface during row bar cutting and air bearing surface lapping in the slider process (3) The throat height varies greatly due to factors such as variations in the processing height of the reproducing element when the air bearing surface is processed on the basis of the reproducing element height.

  The misalignment of exposure that occurs when the reproducing element and the recording element are formed on the wafer is caused by tilting the slider during the floating polishing process, and adding extra materials so that the reproducing element and the recording element have appropriate dimensions. It can correct | amend by removing. However, the direction in which the slider is inclined during polishing must be changed depending on which side the reproducing element and the recording element are relatively displaced.

  In general, since the recording element is formed closer to the surface of the element surface than the reproducing element, if the recording element is formed relatively closer to the air bearing surface than the reproducing element, the slider element If the reproducing element is formed so as to be relatively closer to the air bearing surface than the recording element, the inflow end side is inclined to remove more than the element surface side. The misalignment is corrected by inclining and polishing so as to remove more from the end side.

  However, in reality, at the final stage of the polishing process, if the element height does not sufficiently approach the design dimensions, neither the recording element nor the reproducing element can accurately measure the element height. When the element is formed so as to be relatively closer to the air bearing surface than the recording element, once the processing has proceeded to such an extent that the height of both elements can be measured accurately, the element surface side of the slider is changed again. If it is inclined to remove more than the inflow end side, there is a possibility that the inflow end side has already been removed too much, and the slider air bearing surface is not normally formed.

  The present invention solves such a problem in the manufacture of a thin film magnetic head, and the element height of both the read element and the write element can be increased regardless of the relative direction of deviation during wafer production. The object of the present invention is to adjust the height to an appropriate dimension and form the air bearing surface of the slider as a single plane.

  In order to achieve the above object, in the method of manufacturing a thin film magnetic head according to the present invention, a step of separating, for each slider, a wafer on which a plurality of magnetic head elements each having a recording element laminated thereon is formed, and the slider. The air bearing surface of the magnetic head is inclined so as to remove a relatively large amount of the magnetic head element side with respect to the inflow end side, and the recording element is polished to leave a slightly larger amount than a target value (design value); Measuring the respective heights of the recording element and calculating the slider tilt angle for correcting the positional deviation from the deviation from the design value, and based on the calculated tilt angle, both the reproducing element and the recording element are And a step of polishing while changing the tilt angle so as to obtain a desired height.

  The slider inclination angle is calculated by measuring the throat height of the recording element using the resistance measurement value of the resistance element provided for measuring the throat height of the recording element in the slider, and calculating the resistance measurement value of the reproducing element. And measuring the height of the reproducing element.

  After the tilt processing, the method further includes a step of polishing the air bearing surface of the slider by several tens of nanometers in parallel with the processed surface after the tilt processing while monitoring the height of the reproducing element.

  The polishing process after the tilting process is performed by using the resistance measurement value of the resistance element for measuring the height of the reproducing element provided over the resistance element for measuring the throat height of the recording element. This is done while monitoring the height.

  In order to achieve the above object, as another method, in the method of manufacturing a thin film magnetic head of the present invention, a wafer on which a plurality of magnetic head elements each having a recording element stacked on a reproducing element is formed on a row bar. A step of cutting each time, and tilting the row bar so as to remove a relatively large amount of the magnetic head element side with respect to the slider inflow end side, and polishing the recording element until a slightly larger amount than a target value (design value) is left. Measuring the height of each of the reproducing element and the recording element, calculating a row bar inclination angle for positional deviation correction from an average value of deviation from a design value, and based on the calculated inclination angle, Polishing while changing the tilt angle so that both the reproducing element and the recording element have a desired height, and separating the row bar for each slider. And wherein the Mukoto.

  The row bar inclination angle is calculated by measuring the throat height of the recording element using the resistance measurement value of the resistance element provided for measuring the throat height of the recording element in the slider, and calculating the resistance measurement value of the reproducing element. And measuring the height of the reproducing element.

  The row bar inclination angle is calculated by measuring the throat height of the recording element using a resistance measurement value of a resistance element provided for measuring the throat height of the recording element between the sliders, and using the resistance measurement value of the reproducing element. Then, the height of the reproducing element is measured.

  After the tilt processing, the method further includes a step of polishing the air bearing surface of each slider in the row bar in parallel with the processed surface after the tilt processing while monitoring the height of the reproducing element individually. .

  The polishing process after the tilting process is performed by using the resistance measurement value of the resistance element for measuring the height of the reproducing element provided over the resistance element for measuring the throat height of the recording element. This is done while monitoring the height.

  The step of cutting the wafer for each row bar is preferably performed for each area formed in the same stepper field of the wafer.

  The step of calculating the row bar inclination angle is obtained by calculating a row bar inclination angle for correcting a positional deviation from a linear approximation of a distribution within the row bar of a deviation from a design value of the height of each of the reproducing element and the recording element. Including a step of calculating as an optimum value that linearly changes from end to end, and the tilting step includes a row bar so that both the reproducing element and the recording element have a desired height based on the calculated tilt angle. It may include a step of polishing while gradually changing the inclination angle that linearly changes from end to end.

  In order to achieve the above object, in the thin film magnetic head of the present invention, a slider, a reproducing head having a reproducing element provided on the element surface of the slider, and a recording element provided adjacent to the reproducing head are provided. The reproducing element and the recording element defined by a given magnetic recording density, and the recording element height and the recording element height defined by the track width. The standard deviation of the statistical distribution is within 10% of the average value of each height dimension, and the statistical distribution of the deviation from 90 degrees of the angle between the air bearing surface and the element surface after the air bearing surface polishing is The standard deviation is 0.15 degrees or more.

  According to the present invention, the height of both elements can be adjusted to an appropriate dimension regardless of the relative direction of deviation between the reproducing element and the recording element during wafer manufacturing.

  First, the configuration and operation concept of the thin film magnetic head (perpendicular magnetic recording head) 30 will be described with reference to FIG. The perpendicular magnetic recording head 30 has a magnetic head element portion in which a reproducing head 31 and a recording head 35 are laminated on the element forming surface of the slider 3 (see FIG. 1). The reproducing head 31 is configured by sandwiching a reproducing element 32 such as a GMR element between a lower magnetic shield 33 and an upper magnetic shield 34. The recording head 35 includes a recording element (main magnetic pole) 36, a return magnetic pole 37, a rear magnetic pole 38, and a conductor coil 39. In perpendicular magnetic recording, a magnetic field is applied to the recording layer 41 sandwiched between the soft magnetic backing layer 42 and the main magnetic pole 36 of the double-layer recording medium 40, and the magnetic material of the recording layer 41 is magnetized 44 in a direction perpendicular to the disk surface. This is a magnetic recording method for recording information. FIG. 3 shows a schematic configuration of the perpendicular magnetic recording head element portion. The height H of the portion narrowed down to the same width as the write track width at the tip of the main magnetic pole 36 is referred to as a throat height. As shown in the relationship diagram of the recording magnetic field strength and the throat height H in FIG. In order to obtain the above, it is necessary to make the throat height H as short as possible. However, if this height is too short, recording writing blurs, and if it is too long, post-recording erasure occurs due to residual magnetization, so that very high accuracy is required. Of course, high accuracy is also required for the height L of the reproducing element 32.

  Next, basic steps for polishing the slider air bearing surface in the manufacturing process of the perpendicular magnetic recording head will be described first. Before the air bearing surface polishing process, the step of separating the magnetic head slider for each single product, the step of polishing the air bearing surface for each single product slider while detecting the height L of the reproducing element and the throat height H of the recording element, In the air bearing surface polishing step, unnecessary portions of the reproducing element and the recording element are gradually removed, and when the height of both the elements approaches the design value, the position of the reproducing element and the recording element is determined from the detected value of the height of both elements. A step of calculating the inclination angle of the inclination processing for deviation correction for each slider, and then, based on the calculated inclination angle, the air bearing surface is further polished while inclining each slider, and the height L of the reproducing element and the recording element The throat height H is simultaneously finished to the designed dimensions, thereby correcting the formation position deviation between the reproducing element and the recording element in the wafer process.

  At this time, in the initial stage of the air bearing surface polishing process, the slider is tilted so that the magnetic head element side is relatively removed from the slider inflow end side, and the recording element is left slightly more than the target value (design value). The step of polishing, the step of measuring the respective heights of the reproducing element and the recording element at that time, the step of calculating the slider inclination angle for misalignment correction from the deviation from the respective design value, the calculated inclination angle Based on this, a process of polishing while gradually changing the tilt angle so that both the reproducing element and the recording element are at the final design value height is achieved. Regardless of which direction of displacement is relatively, both element heights can be adjusted to appropriate dimensions, and the air bearing surface of the slider can be formed as a single plane.

  Thus, unlike the conventional technique, the air bearing surface is polished so as to form the air bearing surface perpendicular to the element surface without performing the slant polishing process, and the processing end point is determined based only on the reproducing element height L. Compared with the recording element overwrite characteristic defect caused by the dimensional variation of the throat height H of the recording element that occurs when it is determined, the defect rate is greatly reduced and the yield is improved.

  Regarding the tilt angle, a resistor designed for measuring the throat height of the recording element is arranged in the slider, and the throat height H of the recording element is measured using the resistance measurement value. The reproducing element height L is measured, and a necessary inclination angle is calculated from a comparison of both values.

After the tilting process, the height L of the reproducing element and the recording element are obtained by polishing the flying surface of each slider individually by monitoring the height of the reproducing element and paralleling the processed surface after the tilting process by several tens of nm. The throat height H is finished to an appropriate size at the same time. Hereinafter, examples will be described in detail.
<Example 1>
FIG. 5 shows the geometric relationship between the angle formed by the air bearing surface of the perpendicular magnetic recording head 30 and the element surface, and the amount of deviation between the recording element and the reproducing element. When the exposure position of the reproducing element 32 and the recording element 36 is shifted by δy at the wafer manufacturing process stage, the angle between the element surface and the air bearing surface is inclined by 90 ° to δθ by polishing the slider air bearing surface. The position shift can be corrected, and the heights of both elements can be finished to appropriate dimensions. The magnitude of the inclination angle is δθ = tan ⁻¹ (d / δy) ≈d / δy, where d is the surface interval between the recording element 36 and the reproducing element 32. FIG. 6 shows the deviation δθ of the angle formed by the air bearing surface and the element surface from 90 ° and the positional deviation between the recording element 36 and the reproducing element 32 when the surface distance between the recording element 36 and the reproducing element 32 is 8.5 μm. An example of a numerical relationship of the correction amount δy is shown.

  Although there are a plurality of slider processes including a polishing step for inclining the slider 3, the best embodiment from the viewpoint of the correction accuracy of the positional deviation between the recording element 36 and the reproducing element 32 is as shown in FIG. This is a single-slider process in which the slider is separated into individual products (step 102), and roughing (step 103) and finishing (step 104) are performed individually before roughing. In general, the amount of processing in rough machining is several tens of μm, and the amount of processing in finishing processing is several tens of nm. Therefore, tilt processing for correcting misalignment is performed only in rough processing, and parallel to the polished surface in finishing processing. To process. The process up to the completion of the slider will be described with reference to FIG. First, the wafer 1 is cut to cut out the row bar 2 including a plurality of magnetic head elements (step 101). Subsequently, the row bar 2 is cut into chips and separated into individual sliders 3 (step 102). Next, the slider 3 is attached to the slider tilting mechanism 4 and pressed against a polishing surface plate (not shown) that rotates the polishing surface, and roughing (tilting) of the air bearing surface is performed (step 103). Subsequently, a single product finishing process (no inclination) is performed in parallel with the polished surface (step 104). Next, the slider 3 is mounted on the air bearing surface groove processing jig 5 (process 105), air bearing surface groove processing and protective film formation are performed (process 106), and the slider 3 is completed (process 107). In addition, the grinding | polishing apparatus currently disclosed by patent document 1 can be used for the grinding | polishing process in process 103 and 104, for example.

  However, since the amount of positional deviation in the wafer manufacturing process of the actual recording element 36 and reproducing element 32 differs for each slider 3 as shown in the example of the distribution on the wafer in FIG. As shown in FIG. 8A, the recording element 36 is formed on the side relatively closer to the air bearing surface than the reproducing element 32. Conversely, as shown in FIG. Both are formed closer to the air bearing surface than 36. In general, since the recording element 36 is formed closer to the surface of the element surface than the reproducing element 32, the recording element 36 is formed so as to be relatively closer to the air bearing surface than the reproducing element 32. For example, as shown in FIG. 8A, the inflow end side of the slider is inclined so as to be removed more than the element surface side, and conversely, the reproducing element 32 is relatively closer to the air bearing surface than the recording element 36. If formed in this way, as shown in FIG. 8B, the misalignment is corrected by inclining and polishing so that the element surface side of the slider 3 is removed more than the inflow end side.

  However, in reality, in the final phase of the polishing process, if the height of the element does not sufficiently approach the design dimension, neither the recording element 36 nor the reproducing element 32 can measure the accurate element height with sufficient accuracy. When the reproducing element 32 is formed so as to be relatively closer to the air bearing surface than the recording element 36 as shown in FIG. 8B, the processing is performed to such an extent that both element heights can be accurately measured. If the element surface side of the slider 3 is tilted so as to be removed more than the inflow end side when it advances, there is a possibility that the inflow end side has already been removed excessively, and the slider floating surface It does not form normally.

  Therefore, in the present invention, in order to solve such a problem and appropriately correct by tilting processing regardless of which direction the positional deviation between the recording element 36 and the reproducing element 32 is relative, The air bearing surface polishing process is performed, which is characterized by the following procedure. FIG. 9 shows a detailed air bearing surface polishing tilt processing procedure according to the present invention. The dotted line in the figure indicates that (a) the recording element 36 is formed closer to the air bearing surface than the reproducing element 32, and conversely (b) the reproducing element 32 is more air bearing than the recording element 36. When it is formed on the side relatively close to the surface, it is a polished surface at each moment during each processing.

  That is, the slider 3 is tilted so that the magnetic head element side is deep, the magnetic head element is exposed to the air bearing surface, and approaches the final design height dimension to some extent, so that the height dimension is sufficiently sensitive. Process until measured (first step). Subsequently, the height dimension of each of the reproducing element 32 and the recording element 36 at that time is measured, and the slider tilt angle for correcting the positional deviation is calculated from the error from the respective designed height dimension ( Second step). Next, polishing is performed while gradually changing the inclination angle so that both the reproducing element 32 and the recording element 36 have the final designed height dimension (third step). When both the reproducing element 32 and the recording element 36 have the appropriate height at the same time, the processing is finished (fourth step). Subsequently, for the purpose of improving the smoothness of the air bearing surface and the element dimensions based on the reproducing element height, a finishing process with a removal amount of about several tens of nanometers is performed (fifth step: tilting is performed at this time). First, the recording element and the reproducing element are polished in equal amounts).

  In this way, it is the best embodiment from the viewpoint of the dimensional accuracy of each of the recording element 36 and the reproducing element 32 to individually process the slider individually from the time of the inclination processing for the positional deviation correction.

  With respect to the inclination angle, as shown in FIG. 10, a resistor 50 is disposed in the slider for measuring the throat height of the recording element 36, the measured throat height H of the recording element 36 is measured using the measured resistance value, and reproduction is performed. The reproducing element height L is measured from the resistance measurement value of the element 32, and a necessary inclination angle is calculated from a comparison between the two values.

Specifically, the tilt angle is calculated as follows. FIG. 11 shows the relationship between the throat height of the recording element 36, the height of the reproducing element 32, and the tilt angle of the slider. H ₀ : Design value of the recording element throat height, L ₀ : Design value of the reproducing element height, H ₁ : Recording element throat height at the time of calculating the tilt angle, L ₁ : Reproducing element height at the time of calculating the tilt angle, and d: Surface spacing between the recording element and the reproducing element. The required tilt angle until the end is δθ = tan ^-1 (d / ((H ₁ -H ₀ )-(L ₁ -L ₀ ))) ≒ d / ((H ₁ -H ₀ )-(L ₁ -L ₀ )).

FIG. 12 is a diagram illustrating an example of the relationship among the throat height H of the recording element, the height L of the reproducing element, and the resistance values of the throat height measuring resistor 50 and the reproducing element. As shown in the figure, since the resistance value and the element size are in an inversely proportional relationship, the dimension cannot be calculated with sufficient accuracy unless the element size approaches the design value to some extent. For example, in the case of a resistance element having the characteristics as in the example of FIG. 12, it has to approach 300 nm until it shows a change rate of 1/10 of the resistance change rate in the vicinity of the design value of 100 nm. Therefore, for example, assuming that the measured value of H ₁ is 380 nm when L ₁ reaches 300 nm during processing with respect to the target values of H ₀ : 150 nm and L ₀ : 100 nm, the tilt angle necessary for correction Is δθ = 0.2 degrees from the above equation.

  In general, since the tilt angle required for correction is very small, even if the polished surface at the time of tilt angle calculation has already tilted slightly from 90 degrees to the element surface (for example, within plus or minus 5 degrees). The calculation of the corrected inclination angle by the above calculation has almost no problem, and the correction angle may be simply added to the inclination angle at that time.

  As shown in FIG. 10, a reproducing element height measuring resistor (for rough machining) 70 arranged so as to overlap the throat height measuring resistor 50 of the recording element 36 is used at the time of starting roughing (final of the reproducing element). This is used for monitoring the processing amount from the size of a few tens of μm before the size of the regenerative element to about 1 μm. The above calculation of the tilt angle is followed by the calculation of the height of the regenerative element. This is done after taking over the resistance value of the device itself. Note that the reproducing element height measuring resistor (for roughing) 70 may be disposed under the recording element throat height measuring resistor 50.

  Single product finishing after tilting is performed by polishing the air bearing surface of each slider 3 by tens of nanometers in parallel with the processed surface after tilting while monitoring the resistance value of the reproducing element 32 individually. The height L of the element 32 and the throat height H of the recording element 35 are simultaneously finished to appropriate dimensions.

According to the first embodiment, the height of both elements is adjusted to an appropriate dimension and the slider is lifted regardless of the relative direction of deviation between the reproducing element and the recording element during wafer manufacture. The surface can be formed as a single plane. Further, the recording element overwrite characteristic defect due to the dimensional variation in the throat height of the recording element is greatly reduced, and the yield is improved.
<Example 2>
FIG. 13 is a diagram illustrating an example of a machining process in the case where the tilt machining for correcting the misalignment is performed in a row bar state. In this embodiment, until the rough machining (step 202), which is rough machining, is performed in the state of the row bar 2, then chip cutting for dividing into individual sliders is performed (step 203). Finishing is performed to improve the smoothness of the air bearing surface and the element dimensions based on the reproducing element height (step 204).

  The deviation distribution shown in FIG. 7 is obtained by extracting a small portion of the slider on the wafer, and the other sliders 3 that have not taken the data points smoothly change the deviation. . Therefore, there is a certain amount of average deviation component in one row bar, and the dimensional accuracy can be improved to some extent by correcting the inclination in units of row bars.

  Since the tilting process is performed in units of row bars, the resistor 50 designed for measuring the throat height of the recording element as shown in FIG. 14 is arranged in the slider or between the sliders. Since the resistor 60 designed for measuring the height of the reproducing element is also required when arranged between the sliders, the reproducing element and the recording element are alternately arranged every other slider. Further, as shown in FIG. 15, both the reproducing element resistor 60 and the recording element resistor 50 between the sliders are arranged in an overlapping manner. From the viewpoint of dimensional accuracy, the overlapping arrangement method that can arrange a large number of total resistors is a more suitable form.

  As shown in FIG. 14 and FIG. 15, the element height measuring resistors disposed between the sliders for polishing with a row bar include rough machining 70, finishing machining, and machining termination reference 80. Among these, for finishing processing, two types of recording element throat height measurement 50 and reproducing element height measurement 60 are prepared, and they are arranged alternately or overlapping each other. The positional deviation between the reproducing element and the recording element is corrected by calculating the row bar inclination angle based on the measured values of these resistors.

Example 1 is the best mode from the viewpoint of the dimensional accuracy of the recording element, but in order to make the process more suitable for mass production of the product, the row bar process is applied to the inclined machining as in Example 2 above. May be.
<Example 3>
FIG. 16 shows a machining process in the case of performing a tilting process for positional deviation correction and a finishing process in the state of a row bar to improve the smoothness of the air bearing surface and the element size based on the reproducing element height. It is a figure which shows an example. In this embodiment, a slanting process (step 302), which is a roughing process, and a subsequent finishing process (step 303) are performed in the state of the row bar 2, and then a chip is cut to be divided into individual sliders (step 306). ) To complete the slider.

  The tilt processing is the same as in the second embodiment, and the positional deviation between the reproducing element and the recording element is corrected by calculating the row bar tilt angle based on the measured value of each resistor disposed in the slider or between the sliders. .

Compared to the second embodiment, since the finishing process is performed with a row bar, the apparatus and process are simpler and easier and more suitable for mass production of products, although it is slightly inferior from the viewpoint of dimensional accuracy.
<Example 4>
Each quadrangle surrounded by a dotted line in FIG. 7 is one of the stepper fields for exposure at the time of element formation. In general, a row bar extends over two or three of these stepper fields. From the stepper principle, at the joint between the stepper field and the stepper field, the change in the amount of deviation between the recording element and the reproducing element tends to be discontinuous. In the process depending on the row bar as in the second and third embodiments, If the row bar is divided at the seam of the stepper field, the distribution of the deviation amount in the row bar is more uniform. The process flow is exactly the same as in FIGS. 13 and 16, except that the length of the row bar is reduced from 1/2 to 1/3. In this way, the tilting process may be performed in units of row bars divided at the joint of the stepper field. Thereby, the height dimensional accuracy of the reproducing element and the recording element is improved as compared with the second and third embodiments.
<Example 5>
The distribution of the shift amount in the row bar is not uniform at all, but is not completely random. Therefore, as in the second, third, and fourth embodiments, when performing tilt machining in units of row bars, instead of uniformly tilting all the sliders in the row bar, the distribution of the corrected tilt angle δθ of each slider in the row bar is changed. Processing may be performed with an inclination that is linearly changed from end to end of the row bar calculated from linear approximation.

  FIG. 17 shows an example of the distribution in the row bar of the corrected tilt angle δθ calculated from the element shift amount of each slider. In this example, the number of sliders in the row bar is 45. The data points in the figure are distributed almost linearly with some errors. The straight line in the figure is a linear approximation of data points, and in the example of this figure, it is a straight line represented by y = 0.0023x + 0.2448. Therefore, after the step of calculating the inclination angle in the second step of polishing the air bearing surface, the inclination angle is linearly so that the end of the row bar on the slider number 1 side is 0.247 degrees and the end on the slider number 45 side is 0.348 degrees. If the row bar tilt mechanism 6 is set so as to change, the element dimensional accuracy can be further improved as compared with the case where the entire average value of 0.298 degrees is applied to the whole as in the second, third, and fourth embodiments. .

  Next, the yield improvement effect by the inclination machining of each of the above embodiments will be described below. FIG. 18 shows the yield with respect to the recording element throat height specification when the tilting process is not performed. The positional deviation variation between the recording element and the reproducing element in the wafer process is 100 nm at 3σ. On the other hand, in the slider processing process, processing is performed based on the height of the reproducing element, but the variation in the reproducing element height is the case when finishing with a row bar, when finishing with a single slider, 50 nm. Is 10 nm. Here, since the required specification of the reproducing element height is also considered to be 50 nm, the yield loss from the viewpoint of the reproducing element height is not considered here (actually, it is 99.7% because 3σ is considered) . On the other hand, the throat height of the recording element is defined by a deviation from the right angle (90 degrees) between the slider floating surface and the element surface. However, even if polishing is performed assuming a right angle, the angle varies to some extent. The magnitude of the variation is equivalent to 20 nm when the angle variation is converted into the throat height variation of the recording element.

  Accordingly, when the row bar finish processing (no tilt) is performed after the row bar rough processing (no tilt), the variation accuracy of the throat height of the recording element is 3σ, which is 113.6 nm from the square root of the square sum of 100 nm, 50 nm, and 20 nm. It becomes. On the other hand, the required specification of the recording element throat height of 50 nm is equivalent to 1.321 times the standard deviation σ of the distribution having such a variation, so the distribution falling within this range is 81.3% of the entire population, which is This is the yield in this case.

  Similarly, when a single slider finishing process (without tilting) is performed after row bar roughing (without tilting), the throat height variation accuracy of the recording element is 3σ, and the square root of the square sum of 100 nm, 10 nm, and 20 nm. To 102.5 nm. From the same calculation, the required specification 50 nm corresponds to 1.464 times the standard deviation σ of the same distribution, so the distribution that falls within this range is 85.7% of the entire population, and this is the yield in this case.

  In the case where the tilting process is not performed, there is no advantage of performing the roughing process with a single slider, so such a process is not considered.

  On the other hand, FIG. 19 shows the yield with respect to the recording element throat height specification in the case of performing tilting. When the positional deviation correction by the tilting process in the roughing is performed by the row bar (Examples 2 and 3), the average value of the positional deviation correction inclination angles of the sliders in the row bar is uniformly applied to the entire row bar. It is not possible to correct all the displacements of each slider. The accuracy improvement effect by the positional deviation correction tilt processing in units of row bars is about 60% of the positional deviation variation between the recording element and the reproducing element on the wafer in terms of the dimensional variation in the throat height of the recording element. That is, if the positional deviation variation in the wafer process is 100 nm, it is converted to the variation in the throat height dimension of the recording element to be 60 nm.

  On the other hand, in the slider processing process, basically, the processing is basically performed based on the height of the reproducing element as described above. However, the variation in the reproducing element height is caused by finishing with a row bar (implemented). Example 3) is 50 nm, and when finished with a single slider (Example 2), it is 10 nm. Here, similarly to the above, since the required specification of the reproducing element height is considered to be 50 nm, the yield loss from the viewpoint of the reproducing element height is not considered here.

  On the other hand, the tilting process itself is not completely finished at the target angle, and the angle varies to some extent. The magnitude of the variation is equivalent to 20 nm when the angle variation is converted into the throat height variation of the recording element. Therefore, in the case of performing the row bar finishing process (without inclination) after the inclined roughing process by the row bar (Example 3), the throat height variation accuracy of the recording element is 3σ, and the square root of the square sum of 60 nm, 50 nm, and 20 nm. To 80.6 nm. On the other hand, the required specification 50 nm for the recording element throat height corresponds to 1.861 times the standard deviation σ of this distribution, so the distribution that falls within this range is 93.7% of the total population, which is the yield in this case It becomes.

  (Example 2) The throat height variation accuracy of the recording element is 6σ from the square root of the sum of squares of 60 nm, 10 nm, and 20 nm when the finishing process is performed with a single slider after the rough roughing with the row bar. It becomes. On the other hand, the required specification of the recording element throat height of 50 nm corresponds to 2.343 times the standard deviation σ of this distribution, so the distribution falling within this range is 98.1% of the entire population, which is the yield in this case It becomes.

  In addition, when both tilt roughing and finishing are performed with a single slider (Embodiment 1), the effect of improving the misalignment by the tilting process results in 0 nm variation on the wafer, but the actual tilting process itself is It is not completely finished according to the target angle, and the angle varies to some extent. The magnitude of the variation is equivalent to 20 nm when the angle variation is converted into the throat height variation of the recording element.

  Accordingly, the variation accuracy of the throat height of the recording element in this case is 32.4, and is 22.4 nm from the square root of the square sum of 10 nm and 20 nm. On the other hand, the required specification 50nm for the recording element throat height is equivalent to 6.708 times the standard deviation σ of this distribution. Therefore, the distribution within this range is 100.0% of the total population (significant figures, decimal points). This is the yield in this case.

  As summarized in FIG. 18 and FIG. 19, when there is a relationship between the dimensional variations and the required specifications as described above, in any case, sufficiently significant yield improvement can be achieved by performing inclined machining. It turns out that there is an effect.

  In addition, as in the fourth and fifth embodiments, in the case of the row bar divided for each stepper field, or when the tilt process is performed by linearly changing the tilt angle in the row bar, the above-described misalignment correction tilt processing in units of row bars. The accuracy improvement effect by is further improved than 60% (the number is lower), and corresponding details are omitted, but there is a further yield improvement effect according to the same calculation.

  The geometrical features that appear on the product slider as a result of the tilting process according to the present invention are described below. The dimensional specifications of the magnetic head element are all defined from the required recording density. For a given recording density, the track widths Twr and Tww necessary to realize the recording density are defined. With respect to the track width, the reproducing element height L is set as a dimension of 80 to 100% of Twr. It is prescribed. Similarly, the recording element throat height H corresponding to Twr is also defined from Twr.

  In general, the variation specification of element dimensions is 3σ of the variation (three times the standard deviation) and 1/3 of the size, and products that fall within the variation specification are shipped as products. Therefore, the dimensions of devices that are on the market as products are generally within 10% of the average value.

  When tilting is performed and the air bearing surface is polished so that the slider air bearing surface and the element surface are at right angles, the angle variation is about 0.15 degrees. This is a misalignment between the recording element and the reproducing element. Is a value corresponding to 20 nm.

  However, the positional deviation variation between the recording element and the reproducing element in the wafer process is about 100 nm, and even if this positional deviation accuracy is improved in the future, it is limited to about 30 nm. In order to keep both dimensions within the above specifications, it is necessary to perform tilting. In this case, the distribution of the angle formed by the slider air bearing surface and the element surface is greater than 0.15 degrees.

  As described above, through the slant polishing process of the slider air bearing surface according to each embodiment of the present invention, the direction of deviation of the reproducing element and the recording element during wafer manufacturing is relatively either direction. Both the element heights can be adjusted to appropriate dimensions, and the air bearing surface of the slider can be formed as a single plane. Further, the recording element overwrite characteristic defect due to the dimensional variation in the throat height of the recording element is greatly reduced, and the yield is improved.

It is a figure which shows the slider processing process including the single-piece floating surface inclination process by Example 1 of this invention. It is a figure which shows the structure and operation | movement concept of a perpendicular magnetic recording head. It is a block diagram of a perpendicular magnetic recording head element part. It is a figure which shows the relationship between the recording magnetic field strength of a perpendicular magnetic recording head, and the throat height of a recording element. FIG. 5 is a diagram showing a geometrical relationship between an angle formed by an air bearing surface of a perpendicular magnetic recording head and an element surface, and a shift amount of a recording element and a reproducing element. It is a figure which shows an example of the numerical relationship of the angle | corner which the air bearing surface of a perpendicular magnetic recording head and an element surface make, and the deviation | shift amount correction value of a recording element and a reproducing element. It is a figure which shows an example of distribution on the wafer of the position shift in the wafer manufacturing process of the recording element of a perpendicular magnetic recording head, and a reproducing element. FIGS. 4A and 4B are diagrams illustrating a positional deviation between a recording element and a reproducing element. FIG. 5A illustrates a case where the recording element is formed closer to the air bearing surface than the reproducing element, and FIG. The case where it forms in the side close | similar to is shown. It is a figure which shows the floating surface grinding | polishing inclination process procedure for position shift correction of the recording element and reproducing | regenerating element by this invention. FIG. 5 is a diagram illustrating an example of a case where a recording element throat height measurement unit and a reproducing element height measurement unit are arranged in an overlapping manner when an element dimension measurement resistor is arranged in a slider. It is a figure which shows the relationship between the throat height of the recording element of a perpendicular magnetic recording head, reproducing element height, and the inclination-angle of a slider. It is a figure which shows an example of the relationship between the throat height of the recording element of a perpendicular magnetic recording head, the height of a reproducing element, and the resistance value of the resistance element for height measurement. It is a figure which shows the single-piece slider processing process including the row bar floating surface inclination process by Example 2 of this invention. It is a figure which shows an example in the case of arrange | positioning alternately for recording element throat height measurement and for reproducing | regenerating element height measurement, when arrange | positioning the resistor for an element dimension between sliders. FIG. 6 is a diagram illustrating an example of a case where a recording element throat height measurement unit and a reproducing element height measurement unit are arranged in an overlapping manner when the element dimension measuring resistor is arranged between sliders. It is a figure which shows the slider processing process depending on the row bar including the row bar floating surface inclination process by Example 3 of this invention. It is a figure which shows an example in the distribution in a row bar of correction | amendment inclination | tilt angle (delta) theta calculated from the element shift | offset | difference amount of each slider, and its linear approximation. It is a figure which shows the yield with respect to the printing element throat height specification when not performing an inclination process. It is a figure which shows the yield with respect to the printing element throat height specification in the case of performing an inclination process.

Explanation of symbols

1 ... wafer,
2 ... Rowbar,
3 ... Slider,
4 ... slider tilt mechanism,
5 ... Row bar tilt mechanism,
6 ... Air bearing surface groove processing jig,
30: Perpendicular magnetic recording head,
31 ... reproducing head,
32 ... reproducing element,
33 ... Lower magnetic shield,
34 ... Upper magnetic shield,
35. Recording head,
36: Recording element (main magnetic pole),
37 ... Return pole,
38 ... rear magnetic pole,
39: Conductor coil,
40. Double-layer recording media,
41 ... Recording layer,
42 ... soft magnetic backing layer,
44 ... perpendicular magnetization,
50. Recording element throat height measuring resistor,
60: Resistor for measuring reproducing element height (for finishing),
70: Resistor for measuring reproducing element height (for roughing),
80: Reference resistor for processing termination.

Claims (12)

  A process of separating a wafer on which a plurality of magnetic head elements having recording elements stacked on the reproducing element are separated for each slider, and removing the air bearing surface of the slider from the inflow end side relatively to the magnetic head element side. And tilting the recording element to a position where the recording element is left slightly more than the target value, and measuring the respective heights of the reproducing element and the recording element, and correcting the positional deviation from the deviation from the target value. A step of calculating a slider tilt angle, and a step of polishing based on the calculated tilt angle while changing the tilt angle so that both the reproducing element and the recording element have a desired height. A method of manufacturing a thin film magnetic head.   The slider inclination angle is calculated by measuring the throat height of the recording element using the resistance measurement value of the resistance element provided for measuring the throat height of the recording element in the slider, and calculating the resistance measurement value of the reproducing element. 2. The method of manufacturing a thin film magnetic head according to claim 1, wherein the reproducing element is used to measure the height of the reproducing element.   After the tilting process, the method further comprises a step of polishing the air bearing surface of the slider by several tens of nanometers in parallel with the processed surface after the tilting process while monitoring the height of the reproducing element. A manufacturing method of a thin film magnetic head according to Item 1.   Roughing of the air bearing surface prior to the tilting process is performed by measuring the resistance measurement value of the resistance element for measuring the height of the reproducing element provided in the slider so as to overlap the throat height measurement resistance element of the recording element. And performing the polishing process after the tilting process while measuring the height of the reproducing element by using a resistance measurement value of the reproducing element. A method of manufacturing a thin film magnetic head according to claim 3.   A step of cutting a wafer on which a plurality of magnetic head elements each having a recording element laminated on the reproducing element are formed for each row bar, and removing the row bar on the magnetic head element side relatively more than the slider inflow end side. For the purpose of correcting the displacement from the average value of the deviation from the target value, measuring the height of each of the reproducing element and the recording element A step of calculating a row bar inclination angle, a step of polishing based on the calculated inclination angle while changing the inclination angle so that both the reproducing element and the recording element have a desired height, and the row bar A method of manufacturing a thin film magnetic head, comprising the step of separating each slider.   The row bar inclination angle is calculated by measuring the throat height of the recording element using the resistance measurement value of the resistance element provided for measuring the throat height of the recording element in the slider, and calculating the resistance measurement value of the reproducing element. 6. The method of manufacturing a thin film magnetic head according to claim 5, wherein the reproducing element is used to measure the height of the reproducing element.   The row bar inclination angle is calculated by measuring the throat height of the recording element using a resistance measurement value of a resistance element provided for measuring the throat height of the recording element between the sliders, and using the resistance measurement value of the reproducing element. 6. A method of manufacturing a thin film magnetic head according to claim 5, wherein the height of the reproducing element is measured.   After the inclined machining, the floating surface of each slider in the row bar is separated for each individual slider, and the height of the reproducing element is individually monitored, and the number is parallel to the machined surface after the inclined machining. 6. The method of manufacturing a thin film magnetic head according to claim 5, further comprising a step of polishing to a thickness of 10 nm.   In the tilting process, the throat height of the recording element is measured using a resistance measurement value of a resistance element provided for measuring the throat height of the recording element between the sliders, and the resistance element for measuring the throat height of the recording element is measured. Using the resistance measurement value of the resistance element for measuring the height of the reproducing element provided to overlap the upper part, the height of the reproducing element is monitored, and polishing after the tilting process is performed by the reproducing element. 9. A method of manufacturing a thin film magnetic head according to claim 8, wherein the height of the reproducing element is measured using the measured resistance value.   6. The method of manufacturing a thin film magnetic head according to claim 5, wherein the step of cutting the wafer for each row bar is performed for each area formed in the same stepper field of the wafer.   The step of calculating the row bar inclination angle is obtained by calculating a row bar inclination angle for correcting a positional deviation from a linear approximation of a distribution within the row bar of a deviation from a design value of the height of each of the reproducing element and the recording element. Including a step of calculating as an optimum value that linearly changes from end to end, and the tilting step includes a row bar so that both the reproducing element and the recording element have a desired height based on the calculated tilt angle. 6. A method of manufacturing a thin film magnetic head according to claim 5, further comprising a step of polishing while gradually changing an inclination angle that linearly changes from end to end.   The slider has a reproducing head having a reproducing element provided on the element surface of the slider, and a recording head having a recording element provided adjacent to the reproducing head, and is defined from a given magnetic recording density. The standard deviation of the statistical distribution of the height of the reproducing element and the height of the recording element defined from the track width is the average value of the height dimension of the reproducing element and the recording element. The standard deviation of the statistical distribution of the deviation from 90 degrees of the angle formed by the air bearing surface after polishing the air bearing surface and the element surface is 0.15 degrees or more. head.

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