WO2011155271A1

WO2011155271A1 - Method for measuring flare point height of perpendicular magnetic recording head

Info

Publication number: WO2011155271A1
Application number: PCT/JP2011/059946
Authority: WO
Inventors: 徹松村; 俊雄高橋
Original assignee: 株式会社日立製作所
Priority date: 2010-06-11
Filing date: 2011-04-22
Publication date: 2011-12-15
Also published as: JP2011258295A

Abstract

When measuring a magnetic field intensity change rate in order to estimate flare point height, measurement noise, etc., can obscure the difference in the rate of signal intensity change caused by the flare point dimensions, resulting in poor S/N ratios, making it difficult to estimate flare point height. By preparing samples having various flare points, and measuring magnetic field intensity at measurement points at which peak position spacing of a given standard can be obtained for each sample, accurately measuring flare point height in each of these samples using destructive measurement methods such as FIB and etching and preparing a database of the relationships between these flare point heights and magnetic field intensities, it is subsequently possible to estimate flare point height in that sample in a non-destructive manner by measuring the magnetic field intensity in the peak position spacing that becomes the new magnetic head sample standard and referring to the aforementioned database.

Description

Flare point height measurement method for perpendicular magnetic recording head

The present invention relates to a method for measuring a main magnetic pole flare point height of a magnetic head slider mounted on a magnetic recording device such as a magnetic disk device, in particular, a perpendicular magnetic recording head.

In recent years, the recording density of magnetic disk storage devices (HDD: Hard Disk Drive) has been rapidly increasing as the amount of information handled increases. In order to realize further improvement in performance in this trend, a perpendicular magnetic recording system was put into practical use in 2005. The perpendicular magnetic recording system has a feature that fine recording magnetization is thermally stable compared to the conventional in-plane magnetic recording system because magnetic data is arranged perpendicular to the disk surface.

In the in-plane recording method, a very strict accuracy is not required for the height of the magnetic pole of the recording element. However, in the perpendicular recording system, since the height of the magnetic pole greatly affects the recording magnetization distribution, very high accuracy is required. 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.

These dimensions are formed by stopping the polishing process when the processing progresses until each element has an appropriate dimension when polishing the air bearing surface of the magnetic head slider. At that time, with respect to the reproducing element, a current is passed through the guide resistor formed in the vicinity of the element, and the size of the guide resistor is calculated from the resistance value to obtain an estimated height of the actual reproducing element. The element structure does not have a structure in which a current flows in a portion having a dimension that requires high accuracy, and it is very difficult to form a guide resistor in a shape that matches the flare point. Further, regarding the dimensions of the flare point height, (1) the recording element and the reproducing element separated by several μm in the film formation direction, the alignment accuracy of exposure when forming both elements, and (2) the element based on the exposed pattern (3) The perpendicularity of the air bearing surface with respect to the film surface during row bar cutting and air bearing surface lapping in the slider process, (4) The reproducing element height when processing the air bearing surface based on the reproducing element height reference The flare point height varies greatly due to factors such as variations in machining dimensions.

Combined exposure misalignment that occurs when the reproducing element and recording element are formed on the wafer, and milling accuracy when forming the element based on the exposed pattern. The misalignment can be corrected by tilting the slider during the floating polishing process and removing excess material so that the reproducing element and the recording element have appropriate dimensions. However, in order to correct this misalignment correctly, it is necessary to correctly grasp both the size of the reproducing element being processed and the recording element flare point height.

As a method for inspecting the state of the recording element regardless of the guide resistance or the like, for example, as proposed in Patent Document 1, a pseudo perpendicular magnetic recording medium is formed on the air bearing surface of the magnetic head slider to be inspected. Then, perpendicular magnetic recording is performed from the recording element of the magnetic head slider, and the recording state is read by a magneto-optical effect or a magnetic force microscope to estimate the magnetic domain structure of the recording element and judge the quality of the magnetic head. Although there is a method, the size of the element cannot be estimated, and since the measurement is performed via the medium, the result of the observation measurement depends on the characteristic variation of the medium for each medium.

Non-Patent Document 1 discloses a method of measuring and visualizing information recorded on a separately prepared medium by using another magnetic recording / reproducing element. In this case as well, the estimation of the element size is assumed. In addition, since the measurement is performed via the medium, the measurement result depends on the medium.

JP 2006-309836 A JP 2010-3332 A

As means for solving the above-mentioned problem, Patent Document 2 discloses that the magnetic field intensity in the vicinity of the main magnetic pole of the perpendicular magnetic recording head is measured by a magnetic sensor, and the main magnetic pole is calculated from the rate of change in magnetic field strength in the normal direction of the air bearing surface of the magnetic head slider. A manufacturing method is disclosed in which a slider slant polishing process is performed based on an accurate flare point height by estimating a flare point height of the read element and measuring a read element height from an actual measurement of a resistance value of the read element. .

However, when the magnetic field strength change rate measurement for flare point height estimation is performed according to the method described in Patent Document 2, the difference in signal strength change rate due to the flare point height dimension is buried in measurement noise and the S / N ratio is increased. Therefore, it is difficult to estimate the flare point height.

Therefore, an object of the present invention is to provide a technique for obtaining the flare point height of the main pole of a perpendicular magnetic recording head with higher accuracy in a non-destructive manner.

In order to solve such a problem, the flare point height measuring method of the perpendicular magnetic recording head according to the present invention includes a main magnetic pole having a shape narrowed toward the air bearing surface, and an auxiliary magnetic pole and a yoke inside the head. A method for obtaining a flare point height of a perpendicular magnetic recording head comprising a return magnetic pole forming a magnetic circuit and a coil surrounding the magnetic circuit, wherein an electric signal is applied to the coil so as to face the vicinity of the main magnetic pole. The arranged magnetic sensor is scanned, and the flare point height is obtained from the characteristics of the magnetic field intensity distribution in the vicinity of the main magnetic pole calculated from the intensity ratio between the applied electric signal and the signal obtained as the output of the magnetic sensor.

Further, as a preferred aspect of the present invention, the flare point height measuring method is based on the characteristics of the magnetic field intensity distribution in the vicinity of the main magnetic pole calculated from the intensity ratio of the applied electric signal and the signal obtained as the output of the magnetic sensor. The distance from the main magnetic pole to the magnetic sensor is obtained, and the flare point height is obtained from the value of the magnetic field strength with respect to the position of the magnetic sensor.

Further, as a preferred aspect of the present invention, the flare point height measurement method is the highest from the two-dimensional magnetic field strength distribution in a plane parallel to the air bearing surface of the perpendicular magnetic recording head to be measured. The position where the intensity is obtained is specified, and then the positive peak value and the negative peak value of the one-dimensional magnetic field profile obtained by scanning the magnetic sensor in the down track direction of the perpendicular magnetic recording head including the position are obtained. The distance from the main magnetic pole to the magnetic sensor is obtained from the obtained position interval.

According to the present invention, the flare point height of the main magnetic pole of the perpendicular magnetic recording head can be obtained nondestructively and with higher accuracy.

It is a schematic diagram which shows arrangement | positioning at the time of using the magnetoresistive effect element in a magnetic head for the magnetic sensor which measures the magnetic field strength output around the main pole by the Example 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 flare point height of a recording element. It is a figure which shows the magnetic head processing process including the row bar inclination process of the object to which the measuring method of flare point height by this invention is applied, and a row bar finishing process. It is a figure which shows the magnetic head process including the row bar inclination process and the single-piece slider finishing process of the object to which the flare point height measuring method according to the present invention is applied. It is a figure which shows the magnetic head processing process including the single-piece slider inclination process and the single-piece slider finishing process of the object to which the flare point height measuring method according to the present invention is applied. FIG. 2 is a schematic diagram showing a magnetic head slider and a schematic diagram showing directions of orthogonal coordinate axes. It is a figure which shows the difference by the distance from a main magnetic pole to a magnetic sensor of the change of the magnetic field intensity with respect to the value of flare point height. It is a figure which shows the difference in the space | interval of the peak position of the one-dimensional magnetic field profile of a down track direction containing the main-magnetic-pole center part on an air bearing surface in case the distance from a main pole to a magnetic sensor differs. (A) shows the case where the displacement in the Z direction is −0.6 μm, and (b) shows the case where the displacement in the Z direction is 0 μm. It is a figure which shows the change of the peak position space | interval of the one-dimensional magnetic field profile with respect to the distance from a main pole to a magnetic sensor about three types of samples from which flare point height differs. It is a figure which shows the change of the peak position space | interval of the one-dimensional magnetic field profile when the distance of a Z direction is changed gradually about five types of samples from which flare point height differs. It is a figure which shows the magnetic field intensity and flare point height correlation in the distance where the peak position space | interval of 4 micrometers is obtained. It is a schematic diagram which shows an example of the apparatus structure for enforcing the measuring method of the flare point height by an Example. It is a figure which shows the spatial expansion of the magnetic field line loop formed toward a return magnetic pole from a main magnetic pole.

Before describing the embodiments of the present invention, in order to facilitate understanding, first, the configuration and operation concept of a magnetic head slider (perpendicular magnetic recording head) and a general magnetic head slider manufacturing process will be described.
As shown in FIG. 2, 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 a slider (see FIGS. 5 to 8). The reproducing head 31 is configured by sandwiching a reproducing element 32 such as a GMR or TMR 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 section. The main magnetic pole 36 of the recording head 35 has a shape that is narrowed down toward the air bearing surface. The portion of the change point that connects the main magnetic pole 36 to the parallel portion of the main magnetic pole from the fan-shaped portion (flare) is called a flare point, and the height H from the air bearing surface to the flare point is flare. This is called point height. Here, as shown in the relationship diagram of the recording magnetic field strength and the flare point height H in FIG. 4, in order to obtain a large recording magnetic field, it is necessary to make the flare point height H as short as possible. However, if the height dimension is too short, the writing of the recording is blurred. If the height dimension is too long, post-recording erasure occurs due to residual magnetization, so that very high accuracy is required. On the other hand, like the conventional longitudinal magnetic recording, the height L of the reproducing element 32 is of course required to have high dimensional accuracy.

Next, basic steps of the magnetic head slider manufacturing process will be described with reference to FIG.
First, a large number of magnetic head elements are formed in a lattice pattern on a wafer substrate by a process similar to a semiconductor photolithography process. The air bearing surface of the magnetic head slider is formed as a cross section of the substrate and the element layer, and the element dimensions, air bearing surface flatness and smoothness are defined by polishing. Then, it is cut out from the wafer 1 in the shape of a bar-shaped work-in-process 2 in which several tens of sliders are connected (301).

Next, the air bearing surface of the magnetic head slider is formed by polishing in the state of the row bar 2, and the polishing process is a first step, in which the material of the air bearing surface is made of relatively large abrasive grains. Is removed by a thickness of about several μm, and rough processing (302) for roughly aligning the flare point height dimensions of the reproducing element and the recording element within the row bar is performed, and then, as a second step, a relatively small particle size is obtained. With small abrasive grains, the material of the air bearing surface is removed by several tens of nanometers to keep the flatness and smoothness of the slider air bearing surface within the specifications, and the flare point height of each reproducing element and recording element is precisely aligned. It is divided into two steps of finishing (303).

The positional deviation between the reproducing element 32 and the recording element 36 generated in the process of forming the element on the wafer substrate causes the removal of material from the reproducing element 32 and the recording element 36 by tilting the polishing surface in the polishing process. It is corrected by adjusting, and the method of finishing the dimensions of both elements at the same time with high precision at the end of polishing is taken. At this time, the material removal amount in the latter finishing step (303) is about several tens of nm. Since the amount of misalignment that can be corrected during this period is 1 nm or less because it is very small, the correction of the element size due to the inclination of the polishing surface is mainly performed in the first roughing step (302). .

After correcting the positional deviation of the reproducing element dimension and the recording element flare point height by the roughing (302) and reducing the dimensional variation in the row bar as much as possible, the finishing process makes the flatness, smoothness, The row bar whose dimensions of both the reproducing and recording elements are adjusted is then sent to the air bearing surface groove shape forming step (305).

In the air bearing surface groove shape forming step (305), first, a protective film made of a high-hardness thin film for protecting the element portion is formed on the slider air bearing surface, and then a magnetic storage disk device is formed on the slider air bearing surface by photolithography and etching processes. A groove shape is formed to stabilize the slider flying state during operation.

In the above process, the sliders having the groove shape formed on the air bearing surface are finally separated from the row bar 2 one by one, and become the magnetic head slider 3 of the product.

In the process shown in FIG. 5, the tilting process is performed in the row bar state and the finishing process is performed in the row bar state. However, the tilt process is performed in the row bar state as shown in FIG. As shown, the tilting process may be performed by a single item slider, and the finishing process may be performed by a single item slider.

The recording element 36 of the recording head 35 does not have a structure in which an electric current is passed through a portion of the element structure that has a dimension that requires high accuracy, that is, a portion that forms the flare point height H. In general, near the end of the slider manufacturing process, that is, the slider is attached to the suspension, and the magnetic recording medium is actually used. On the other hand, the quality cannot be determined until the magnetic characteristics are measured in the inspection process for recording and reproducing signals.

The configuration and operation concept of the magnetic head slider (perpendicular magnetic recording head) and the basic steps of the magnetic head slider manufacturing process have been described above. With this in mind, the perpendicular magnetic recording head main pole, which is a feature of the present invention, is described. A method for measuring the flare point height will be described below.

First, as shown in FIG. 8, in the perpendicular magnetic recording head, an X axis, a Y axis, and a Z axis orthogonal to each other are defined. The Z axis is the normal direction of the slider flying surface, the Y axis is the direction along the track of the magnetic recording medium (down track direction), and the X axis is the direction perpendicular to the track of the magnetic recording medium (cross track direction).

Fig. 9 shows the calculation result of the change in the magnetic field intensity emitted from the main pole with different flare point heights with respect to the distance in the Z direction from the air bearing surface to the magnetic sensor. The calculation is based on the intersection of perpendicular lines from the center of the main pole to the magnetic film surface when the magnetic film imitating the soft magnetic layer of the perpendicular magnetic recording medium is opposed to the main magnetic pole and the magnetic film is gradually moved away from the air bearing surface. The magnetic field intensity at is calculated. Depending on the condition of each flare point height, the magnetic field intensity decays exponentially with respect to the distance from the air bearing surface, but when the distance from the air bearing surface is the same, the shorter flare point height is. The high magnetic field strength is as described in the explanation using FIG.

Thus, if the distance in the Z direction from the air bearing surface to the magnetic sensor and the absolute value of the magnetic field strength at that position are known, the flare point height can be estimated. However, in order to realize this, it is necessary to accurately measure the distance from the air bearing surface of the magnetic sensor on the order of nm. However, no matter what magnetic sensor is used, accurate direct measurement of this distance is very difficult. Therefore, if the distance can be estimated from the spatial distribution of the measured recording magnetic field strength, the above estimation can be performed. The method is shown below.

FIG. 10 shows a one-dimensional magnetic field profile in the down-track direction including the central portion of the main magnetic pole on the air bearing surface (the point at which the XY plane distribution of the recording magnetic field intensity is maximized). ) Shows the results measured on the plane. 10A shows the case where the Z direction displacement is −0.6 μm, and FIG. 10B shows the case where the Z direction displacement is 0 μm. At each measurement position, the positive peak value of the one-dimensional magnetic field profile corresponds to the magnetic field strength near the main magnetic pole, and the negative peak value corresponds to the magnetic field strength near the return magnetic pole. As you can see, if the Z-direction distance from the air bearing surface of the magnetic sensor is different, the position of the positive peak value and the negative peak value in the one-dimensional magnetic field profile in the down-track direction moves, and the peak position interval changes. I understand that This is because the lines of magnetic force generated from the main pole by passing a current through the coil are directed to the return pole to form a spatially widened loop as shown in FIG. This is because it changes along the distance from the magnetic sensor to the magnetic sensor. Further, the intensity of the one-dimensional magnetic field profile is different because the magnetic field intensity is exponentially attenuated with respect to the distance from the air bearing surface.

FIG. 11 shows the result of calculating the relationship between the peak position interval and the distance in the Z direction from the air bearing surface by simulation. It can be seen from the graph that the peak position interval decreases as the magnetic sensor approaches the air bearing surface. It can also be seen that even if the flare point height changes, the relationship between the peak position interval and the Z-direction distance from the air bearing surface has little effect. Therefore, the distance in the Z direction from the air bearing surface can be uniquely determined by measuring the peak position interval in the one-dimensional magnetic field profile.

Therefore, first, prepare samples with various flare points, measure the magnetic field strength of each sample at the measurement point where a certain standard peak position interval is obtained, and then destructive such as FIB or etching. If the flare point height of each sample is accurately measured by the measurement method and the relationship between the flare point height and the magnetic field strength is prepared as a database, the magnetic field strength of a new magnetic head sample can be measured thereafter. By referring to the database, the flare point height of the sample can be estimated nondestructively.

On the other hand, the above measurement is based on the premise that the measurement point is gradually separated in the Z direction from the vicinity of the air bearing surface, starting from the point where the magnetic field strength is maximum in the XY plane. First, a raster scan of the measurement point in the X direction or the Y direction is performed in the immediate vicinity of the air bearing surface, and the measurement value is determined as the maximum position.

Summarizing these descriptions, the method for measuring the main magnetic pole flare point height of the perpendicular magnetic recording head according to the first embodiment is as follows.
(1) The magnetic sensor is brought close to the air bearing surface, and the measurement point is raster scanned in the X direction or the Y direction to determine the point where the measurement value is maximized, and set it as the main magnetic pole center.
(2) The magnetic sensor is scanned about 30 microns in the down track direction including the center point, and the one-dimensional magnetic field profile is measured.
(3) The measurement of the one-dimensional magnetic field profile is repeated while gradually moving the magnetic sensor along the Z direction, and the positive peak value and the negative value in the measured one-dimensional magnetic field profile in the down-track direction with respect to the displacement in the Z direction are measured. The change of the interval of the position where the peak value is obtained is obtained.
(4) A positive or negative magnetic field strength peak value is plotted against the interval between positions where a positive peak value and a negative peak value are obtained in the measured one-dimensional magnetic field profile in the down-track direction. Obtain the value of the magnetic field strength at the interval.
(5) The magnetic field strength value at a certain reference peak position interval obtained in (4) above is compared with a separately prepared database of samples with known flare point heights, and the flare point of the sample is compared. Estimate the height.

In the first embodiment, the magnetic sensor has various types such as an induction coil, a Hall effect element, a magnetoresistive effect element (AMR, GMR, TMR, etc.). It does not affect the essence of the present invention. Therefore, here, an embodiment will be described in which a magnetoresistive effect element mounted as a reproducing element on a magnetic head slider is used as a magnetic sensor.

A magnetoresistive element is an element whose electric resistance changes in accordance with a change in the intensity of an external magnetic field, and has a certain size (width: several tens of nm × height: several tens of nm × thickness: Therefore, the information on the resistance value obtained by the measurement does not represent the distribution of the recording magnetic field itself generated by the electric signal input to the coil 39 of the recording head 35, but the size of the magnetoresistive element. However, with regard to the purpose of the present invention, that is, the estimation of the recording element size, the sample of the target sample is compared with a separately prepared database of samples with known flare point heights. Since it is assumed that the size is estimated, measurement using a magnetoresistive element having a finite size may be performed.

FIG. 14 shows a configuration diagram of the apparatus used for the measurement. The magnetoresistive element used as a magnetic sensor for measurement is a magnetic head slider for a magnetic disk storage device fixed to a sensor holding jig attached to a fine movement stage having a three-dimensional translational freedom degree, and the magnetic head terminal portion is fixed to the holding jig. The terminal placed above was wire-bonded. The magnetic head slider with the recording element to be measured is the one where the row bar after polishing is fixed to the row bar holding jig attached to the fixed base, and the magnetic head terminal is wire bonded to the terminal placed on the holding jig Was used. An arrangement of a magnetic head slider provided with a recording element to be measured and a magnetic head slider provided with a magnetoresistive effect element serving as a magnetic sensor is shown in FIG. 1 as a schematic diagram.

The measurement is performed by inputting an electric signal of a sine high frequency with a constant effective voltage to the target recording head, and an output voltage generated as a sine high frequency of the same frequency as the input sine high frequency in a magnetoresistive effect element arranged in the immediate vicinity of the recording element. This is done by recording the ratio of the intensity to the input signal and the phase difference. A magnetoresistive element measures a change in resistance value of an element that changes in accordance with an external magnetic field as a voltage generated at both ends of the element in a state where a constant sense current is passed through the element. Therefore, the change in the output of the magnetoresistive effect element when the magnetoresistive effect element, which is a magnetic sensor, is slightly displaced three-dimensionally relative to the recording element to be measured is the change of the element described above. This corresponds to the distribution of the magnetic field strength in the vicinity of the recording element including the effect of a finite size.

The three-dimensional minute displacement of the magnetic sensor in Example 1 was controlled with a three-axis piezo stage that can be positioned with a resolution of 1 nm in each of the X, Y, and Z directions. Any actuator and stage that can accurately position with a resolution of 1 nm or less can be used.

Further, as shown in FIG. 2, the recording head 35 forms a magnetic circuit in the order of the main magnetic pole 36, the medium recording layer 41, the medium soft magnetic backing layer 42, the medium recording layer 41, the return magnetic pole 37, and the rear magnetic pole 38. Therefore, the direction of the magnetic field is reversed between the vicinity of the main magnetic pole and the vicinity of the return magnetic pole. Therefore, in order to facilitate the detection of the main magnetic pole center in the vicinity of the main magnetic pole, the phase is simultaneously measured in addition to the output ratio. This is because if the direction of the magnetic field is reversed, the phase of the output signal is also shifted by 180 degrees, so that the magnetic field distribution near the main magnetic pole and the magnetic field distribution near the return magnetic pole can be easily distinguished.

The magnetoresistive effect element measured in a state in which a constant current sense current is passed through a magnetoresistive effect element which is a magnetic sensor arranged in the vicinity of the recording element and a sine high frequency signal having a constant effective voltage applied to the recording head to be measured The measurement of the intensity ratio of the voltage output signal and the phase difference was performed by a vector network analyzer capable of measuring both of them simultaneously.

While applying a sinusoidal high-frequency signal with a constant effective voltage from one of the network analyzer ports to the perpendicular magnetic recording head to be measured, the magnetic field strength via a bias T to separate the DC and RF signals from the constant current power supply Applying a constant current to the magnetoresistive effect element as a sensor and minutely displacing the vicinity of the recording element, a change in the intensity of the output sine high-frequency signal generated in the magnetoresistive effect element is networked via a bias T and an amplifier. Three-dimensional data map information is obtained by taking in the other port of the analyzer and processing the data by comparing the signal intensity comparison and phase comparison of both ports with the position information of the piezo stage.

Next, in order to verify the estimation method of the main magnetic pole flare point height according to the present invention, a sample in which the flare point height is shaken about 30 nm in advance in the row bar by processing is processed in the Z direction from the air bearing surface of the sensor by the above method. While reducing the distance by 200 nm, a one-dimensional magnetic field profile was measured by scanning a magnetic sensor about 30 microns in the down track direction including the main magnetic pole center point. FIG. 12 shows a plot of the measurement results obtained by measurement, with the horizontal axis representing the Z-direction displacement and the vertical axis representing the peak position interval. It is observed that the peak position interval decreases as the slider approaches the Z direction. Here, the reason why the peak position interval is constant after being reduced to a certain value is that the magnetic head slider, which is a magnetic sensor, and the magnetic head row bar to be measured are in physical contact with each other and cannot be approached any further. is there.

FIG. 13 is a graph of magnetic field strength and flare point height at a distance where a peak position interval of 4 μm is obtained, and is a result of measurement for a plurality of samples having different flare point heights in the row bar. It was confirmed that there was a significant correlation between them. That is, for a certain reference peak position interval, the recording magnetic field intensity at that distance is uniquely determined with respect to the flare point height of each sample. Therefore, it was confirmed that the flare point height can be estimated from the recording magnetic field intensity measured by the sensor by using this method.

As described above, according to the embodiment of the present invention, the main magnetic pole flare point height of the perpendicular magnetic recording head can be measured more accurately in a non-destructive manner. Further, in the slider step, the flare point height is estimated using the main magnetic pole flare point height measurement method of the perpendicular magnetic recording head, and on the other hand, by measuring the reproducing element height from the actual measurement of the resistance value of the reproducing element. In order to calculate the positional deviation between the recording element and the reproducing element in the wafer process by comparing the dimensions of the recording element and the reproducing element, and to correct the positional deviation, an accurate flare point is calculated in the slider process. The slider slant polishing process based on the height can be performed, and the slider manufacturing yield is improved. Also, at the end of the slider process, defective products are selected based on the magnetic characteristics determined by the flare point height, so that a slider that is found to be defective at this stage is attached to the suspension and the signal is actually sent to the magnetic recording medium. Thus, it is no longer necessary to send an inspection process for recording / reproducing, thereby reducing production management loss.

The main magnetic pole flare point height measurement method of the perpendicular magnetic recording head of the present invention can be applied to the inspection and manufacture of a perpendicular magnetic recording head mounted on a magnetic storage disk device.

DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Row bar, 3 ... Slider, 4 ... Slider inclination mechanism, 5 ... Row bar inclination mechanism, 6 ... Air bearing surface groove processing jig, 30 ... Perpendicular magnetic recording head, 31 ... Reproduction head, 32 ... Reproduction element, 33 ... Lower magnetic shield, 34 ... Upper magnetic shield, 35 ... Recording head, 36 ... Recording element (main magnetic pole), 37 ... Return magnetic pole, 38 ... Rear magnetic pole, 39 ... Conductor coil, 40 ... Double-layer recording medium, 41 ... Recording layer 42... Soft magnetic underlayer 44. Perpendicular magnetization.

Claims

This is a method for measuring the flare point height of a perpendicular magnetic recording head having a main pole having a shape that is narrowed toward the air bearing surface, a return pole that forms a magnetic circuit with the main pole, and a coil that surrounds the magnetic circuit. Then, an electric signal is applied to the coil, a magnetic sensor disposed so as to face the vicinity of the main magnetic pole is scanned, and calculated from the intensity ratio of the applied electric signal and the signal obtained as the output of the magnetic sensor. A method for measuring a flare point height of a perpendicular magnetic recording head, characterized in that a flare point height of the main magnetic pole is obtained from characteristics of a magnetic field intensity distribution near the main magnetic pole.
2. A method for measuring flare point height of a perpendicular magnetic recording head according to claim 1, wherein a distance from the main magnetic pole to the magnetic sensor is obtained from a characteristic of magnetic field intensity distribution in the vicinity of the main magnetic pole, and the magnetic field intensity with respect to the position of the magnetic sensor. A flare point height measurement method for a perpendicular magnetic recording head, wherein the flare point height of the main magnetic pole is obtained from the value of.
3. The method for measuring a flare point height of a perpendicular magnetic recording head according to claim 2, wherein the distance from the main magnetic pole to the magnetic sensor is two-dimensionally in a plane parallel to the air bearing surface of the perpendicular magnetic recording head as the object to be measured. A position where the highest intensity can be obtained from the magnetic field intensity distribution, and then scanning the magnetic sensor in the down-track direction of the perpendicular magnetic recording head including the position, and a positive one-dimensional magnetic field profile obtained by scanning the magnetic sensor A flare point height measurement method for a perpendicular magnetic recording head, characterized in that the flare point height is obtained from an interval between positions where a peak value and a negative peak value are obtained.
2. The method for measuring flare point height of a perpendicular magnetic recording head according to claim 1, wherein a magnetoresistive effect element of either GMR or TMR is used as the magnetic sensor.
A perpendicular magnetic recording element comprising a main magnetic pole having a shape narrowed toward the air bearing surface, a return magnetic pole that forms a magnetic circuit with the main magnetic pole, a coil surrounding the magnetic circuit, and a reproducing element In the flare point height measurement method of the magnetic recording head,
A plurality of perpendicular magnetic recording heads having different flare points are prepared as samples, a magnetic field is generated from the air bearing surface by energizing the coil of the sample, and a one-dimensional magnetic field is provided by a magnetic sensor disposed opposite the air bearing surface of the sample. Measuring the profile, measuring the magnetic field strength at a measurement point where a certain reference peak position interval of the one-dimensional magnetic field profile is obtained, and subsequently measuring the flare point height of the sample by a destructive measurement method. Creating a database of the relationship between height and magnetic field strength;
A magnetic sensor is opposed to the air bearing surface of the perpendicular magnetic recording head for measurement, the one-dimensional magnetic field profile is measured while moving the magnetic sensor in the normal direction of the air bearing surface, and the magnetic field strength at the reference peak position interval is measured. Measuring process;
Comparing the measured magnetic field strength with the database to estimate the flare point height of the measured perpendicular magnetic recording head;
A method for measuring the flare point height of a perpendicular magnetic recording head, comprising:
6. The method of measuring a flare point height of a perpendicular magnetic recording head according to claim 5, wherein the measurement of the one-dimensional magnetic field profile specifies a position where the highest magnetic field strength can be obtained by moving the magnetic sensor two-dimensionally, A method for measuring flare point height of a perpendicular magnetic recording head, wherein the flare point height is moved in the down track direction including the position.
6. The method of measuring a flare point height of a perpendicular magnetic recording head according to claim 5, wherein the magnetic field intensity is obtained as an intensity of an electric signal applied to the coil of the sample and a perpendicular magnetic recording head for measurement and an output of the magnetic sensor. A method for measuring flare point height of a perpendicular magnetic recording head, characterized in that the flare point height is obtained from an intensity ratio with respect to a received signal.
6. The method for measuring a flare point height of a perpendicular magnetic recording head according to claim 5, wherein in the step of measuring the magnetic field intensity, a phase difference of a one-dimensional magnetic field profile is also measured. Method.
6. The method for measuring flare point height of a perpendicular magnetic recording head according to claim 5, wherein the magnetic sensor is moved by a fine movement stage having a three-dimensional translational freedom degree. Method.
10. The method for measuring a flare point height of a perpendicular magnetic recording head according to claim 9, wherein the fine movement stage is a three-axis piezo stage.
An apparatus for measuring the flare point height of a perpendicular magnetic recording head having a main magnetic pole having a shape narrowed toward the air bearing surface, a return magnetic pole that forms a magnetic circuit with the main magnetic pole, and a coil surrounding the magnetic circuit. ,
Storage means for maintaining the relationship between flare point height and magnetic field strength of a plurality of perpendicular magnetic recording heads having different flare points;
A magnet that measures the one-dimensional magnetic field profile while facing the air bearing surface of the perpendicular magnetic recording head for measurement, moving the magnetic sensor in the normal direction of the air bearing surface, and measures the magnetic field strength at the reference peak position interval. A sensor,
A three-axis piezo stage for controlling the three-dimensional minute displacement of the magnetic sensor;
Estimating the flare point height of the perpendicular magnetic recording head to be measured by comparing the magnetic field strength measured while three-dimensionally displacing the magnetic sensor with the three-axis piezo stage and the relationship of the storage means And a flare point height measuring device for a perpendicular magnetic recording head.
The estimation means obtains the distance from the main magnetic pole to the magnetic sensor from the characteristics of the magnetic field strength distribution near the main magnetic pole, and obtains the flare point height of the main magnetic pole from the value of the magnetic field strength with respect to the position of the magnetic sensor. The flare point height measuring apparatus for a perpendicular magnetic recording head according to claim 11.
The estimation means is such that the distance from the main magnetic pole to the magnetic sensor is a position where the highest intensity can be obtained from a two-dimensional magnetic field strength distribution in a plane parallel to the air bearing surface of the perpendicular magnetic recording head to be measured. Next, the positive peak value and the negative peak value of the one-dimensional magnetic field profile obtained by scanning the magnetic sensor in the down track direction of the perpendicular magnetic recording head including the position are obtained. 13. The flare point height measuring device for a perpendicular magnetic recording head according to claim 12, wherein the flare point height measuring device is obtained from the interval.
12. The flare point height measuring device for a perpendicular magnetic recording head according to claim 11, wherein the magnetoresistive element of either GMR or TMR is used as the magnetic sensor.
The relationship held in the storage means is that a plurality of perpendicular magnetic recording heads having different flare points are prepared as samples, a magnetic field is generated from the air bearing surface by energizing the coil of the sample, and A one-dimensional magnetic field profile is measured by magnetic sensors arranged opposite to each other, a magnetic field intensity at a measurement point at which a certain reference peak position interval of the one-dimensional magnetic field profile is obtained, and then the sample is measured by a destructive measurement method. 12. The flare point height measuring apparatus for a perpendicular magnetic recording head according to claim 11, wherein the flare point height of the perpendicular magnetic recording head is measured.