JP5201328B2 - Method and apparatus for inspecting characteristics of thin film magnetic head element - Google Patents

Description

  The present invention relates to a characteristic inspection method and apparatus for a thin film magnetic head element used in a hard disk drive or the like.

  The thin film magnetic head element is composed of a pair of write element and read element. FIG. 5 is a cross-sectional view illustrating the configuration of the thin film magnetic head element. In the thin film magnetic head element 21, the write element 31 records a signal on the magnetic disk 50 by a magnetic field generated by electromagnetic induction from a current flowing through the coil 32. The read element 41 reproduces a signal by detecting the direction of the magnetic field on the magnetic disk 50 with a magnetoresistive element (MR element 42).

  FIG. 6 is an exemplary perspective view of a slider on which a thin film magnetic head element is formed. As shown in this figure, the thin film magnetic head element 21 is located at the end of the slider 2 together with the electrode 22. FIG. 7 is a conceptual explanatory diagram of a slider manufacturing method. When manufacturing the slider, first, a large number of thin-film magnetic head elements are formed on the wafer and cut into rods (FIG. 7A → B). This bar is the rover. The slider is obtained by further cutting the row bar into individual pieces (FIG. 7 (B) → (C)). Generally, about 80 sliders can be obtained from one row bar. That is, about 80 thin film magnetic head elements exist in one row bar.

  The slider forms part of an HGA (Head Gimbal Assembly) as illustrated in FIGS. 8A and 8B. That is, the slider 2 is assembled to a suspension 7 (gimbal) having the load beam 3 and the flexure 5. The load beam 3 is made of a metal leaf spring, and a dimple 11 projecting toward the flexure 5 is formed at the tip. The load beam 3 and the flexure 5 are integrated by welding, for example, except for the tip portion, and form a suspension 7. The flexure 5 has a main body 5a and a rectangular tongue 5b. The tongue 5b is connected to the main body 5a only on the side of the front end of the main body 5a, and the other sides are cut off. The back surface of the tongue 5b is urged (pressed) by the dimple 11 so that the tongue 5b is substantially parallel to the load beam 3. The slider 2 is fixed on the tongue 5b, and is urged by the dimple 11 through the tongue 5b to maintain an optimum posture in actual recording / reproduction.

  In a hard disk drive (hereinafter referred to as “HDD”), a signal is recorded on the magnetic disk and the signal is reproduced from the magnetic disk while the magnetic disk rotating at high speed and the slider of the HGA are not in contact with each other. The final inspection of the HGA needs to be performed by creating a situation similar to recording / reproduction for an actual HDD. This is called, for example, a dynamic characteristic inspection. Various methods have been proposed for the dynamic characteristic inspection of HGA. In general, the result of recording (writing) and reproducing (reading) data on pseudo media by HGA is compared with the original data, and the output level is compared. The characteristics of the HGA are evaluated based on the missing bits and bits.

As an apparatus for inspecting the characteristics of HGA, for example, an apparatus described in Patent Document 1 below is known.
JP 2002-373476 A

  Since the final inspection of the HGA needs to be performed by creating the same situation as the recording / reproduction for the actual HDD as described above, the HGA must be put into one characteristic inspection device one by one. It is disadvantageous. If the number of characteristic inspection devices is increased in order to improve this, there is a problem of increased cost. Also, if the HGA does not pass the final inspection, expensive parts such as suspensions must be discarded, resulting in an increase in cost. Therefore, it is desirable that the defective product occurrence rate in the final inspection stage is as low as possible. Considering this, one of the reasons why the HGA does not pass the final inspection is considered to be a defect of the thin film magnetic head element. The defect of the thin film magnetic head element is further divided into a defect of a write element and a defect of a read element.

  Here, with respect to the read element, it is possible to obtain characteristics (static characteristics) by applying an external magnetic field, so that it is possible to perform a static characteristics inspection not only in the process after the slider but also in the state of a row bar or a wafer. Therefore, a slider having a thin film magnetic head element with a defective read element can be excluded with a relatively high probability at an early stage. That is, the probability that the read element is defective in the final inspection of the HGA is relatively low.

  On the other hand, the write element cannot be subjected to static characteristic inspection like the read element, and the gap between the disk and the thin film magnetic head element needs to be managed with high accuracy when inspecting the characteristics of the write element. It can be said that it is difficult to inspect the light element in the process before the final inspection. For this reason, the current situation is that it is necessary to determine whether or not the write element is acceptable only by the final inspection of the HGA. Therefore, the probability that a defective write element exists in the final inspection of the HGA is higher than that of the read element.

  Such a problem becomes more conspicuous in the perpendicular magnetic recording system. This is because the perpendicular magnetic recording method has a higher recording density (narrow energy distribution) than the horizontal magnetic recording method, so that the yield of the thin-film magnetic head element is poor. In the perpendicular magnetic recording system, it is necessary to manage the gap between the disk and the thin-film magnetic head element in nanometer units when inspecting the characteristics of the write element, and the write element is inspected before the final inspection of the HGA. It is even more difficult to do this than with the horizontal magnetic recording system. Since the reproduction principle (reading principle) is the same for both the horizontal magnetic recording method and the perpendicular magnetic recording method, the probability that a defective product will remain in the final inspection of the HGA for the above reason is relatively low. .

  The present invention has been made in view of such a situation, and the object thereof is lower than the case of inspecting the characteristics of the thin film magnetic head element of the HGA by introducing one HGA into one characteristic inspection apparatus. It is an object of the present invention to provide a thin film magnetic head element characteristic inspection method and apparatus capable of improving the throughput and capable of inspecting the recording characteristics of the thin film magnetic head element before the final inspection of the HGA. .

The first aspect of the present invention is a method for inspecting characteristics of a thin film magnetic head element. This method
Flexible or soft magnetic media;
A plurality of thin film magnetic head elements each having a pair of write elements and read elements are integrated in a row and integrated into a single row, and cut into individual pieces to form a plurality of sliders each having a single thin film magnetic head element. Use
Recording in which a predetermined signal is recorded on a track of the magnetic medium by a write element of the thin film magnetic head element while moving the magnetic medium relative to the row bar in a state where the row bar is in contact with the magnetic medium. Process,
A reproduction step of reproducing the predetermined signal recorded by the recording step with a read element;
And an evaluation step for evaluating characteristics of the thin film magnetic head element based on a reproduction result in the reproduction step.

  In the characteristic inspection method according to the first aspect, in the reproduction step, the magnetic medium is moved back relative to the row bar, and then the magnetic medium is moved with the row bar in contact with the magnetic medium. While moving relative to the row bar in the same direction as during recording in the recording step, the read element is paired with the write element that has performed recording on the track from the track on which the predetermined signal is recorded. The predetermined signal may be reproduced.

  In the characteristic inspection method according to the first aspect, the recording step may record a predetermined signal on separate tracks of the magnetic medium by using write elements of a plurality of thin film magnetic head elements.

  In this case, the reproducing step may reproduce the predetermined signal recorded on each track by read elements of a plurality of thin film magnetic head elements.

A second aspect of the present invention is a thin film magnetic head element characteristic inspection apparatus. This device
Flexible or soft magnetic media;
A plurality of thin film magnetic head elements having a pair of write elements and read elements are aligned in one row and integrated into a single piece, and a plurality of sliders each having one thin film magnetic head element are obtained by cutting into individual pieces. Holding means for holding the magnetic medium in contact with the magnetic medium;
Moving means for moving the magnetic medium relative to the row bar;
While the row bar is in contact with and held by the magnetic medium by the holding means, the magnetic medium is moved by the write means of the thin film magnetic head element while the magnetic medium is moved relative to the row bar by the moving means. An inspection unit that evaluates characteristics of the thin film magnetic head element based on a result of reproducing a predetermined signal recorded on a track by a read element.

  In the characteristic inspection apparatus according to the second aspect, the predetermined signal may be reproduced from a track on which the predetermined signal is recorded, by a read element paired with a write element that has performed recording on the track.

  In the characteristic inspection apparatus according to the second aspect, recording of a predetermined signal by a write element of a plurality of thin film magnetic head elements may be performed on separate tracks of the magnetic medium.

  In this case, the predetermined signal may be reproduced for each track by the read elements of the plurality of thin film magnetic head elements.

  It should be noted that any combination of the above-described constituent elements, or a conversion of the expression of the present invention between systems or the like is also effective as an aspect of the present invention.

  According to the present invention, a predetermined signal is recorded on the magnetic medium by the write element of the thin film magnetic head element while the row bar is in contact with the flexible or flexible magnetic medium, and the read signal is reproduced by the read element. Since the characteristics of the thin-film magnetic head element are evaluated based on the results, it is not necessary to manage the gap between the magnetic media and the thin-film magnetic head element. Thus, the recording characteristics of the thin film magnetic head element can be inspected. Therefore, the throughput can be improved at a lower cost than the case of inspecting the characteristics of the thin film magnetic head element of the HGA by putting one HGA in one characteristic inspection apparatus one by one, and more than the final inspection of the HGA. The recording characteristics of the thin film magnetic head element can be inspected before.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component and member shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 1 is a conceptual perspective view illustrating the configuration of a characteristic inspection apparatus 100 according to an embodiment of the invention. The characteristic inspection apparatus 100 includes a magnetic medium 110, a holder 130 as an example of a holding unit, a pair of rollers 150A and 150B as an example of a moving unit, and an inspection unit 170.

  The magnetic medium 110 is flexible or flexible, and for example, a magnetic tape can be used. The holder 130 can move at least in the vertical direction (direction in which the distance to the magnetic medium 110 changes), and holds the row bar 20 so as to be able to contact the magnetic medium 110 by, for example, vacuum suction or a mechanical chuck. The row bar 20 includes a plurality of thin film magnetic head elements 21 each having a pair of write elements and read elements arranged in a row and integrated, and a plurality of thin film magnetic head elements 21 each having one thin film magnetic head element 21 by being cut into individual pieces. It becomes a slider.

  The pair of rollers 150A and 150B around which the magnetic medium 110 is wound are rotated by driving means (not shown) such as a motor, thereby causing the magnetic medium 110 to move linearly relative to the row bar 20. The direction of linear movement is preferably a direction perpendicular to the longitudinal direction of the row bar 20. The inspection unit 170 evaluates the characteristics of each thin film magnetic head element 21 based on the reproduction result of a predetermined signal (inspection signal) recorded on the magnetic medium 110 from each thin film magnetic head element 21 of the row bar 20. As shown in an enlarged view in FIG. 2, the probe 171 of the inspection unit 170 is in contact with the electrode 22 corresponding to each thin film magnetic head element 21. The probe 171 is mechanically supported on the holder 130 side.

  FIG. 3 is a conceptual procedure explanatory diagram showing the flow of the characteristic inspection of the thin film magnetic head element by the characteristic inspection apparatus 100 shown in FIG. Hereinafter, the flow of characteristic inspection in the present embodiment will be described with reference to FIG.

Recording process: While the row bar 20 is held in contact with the magnetic medium 110 by the holder 130, the magnetic medium 110 is linearly moved relative to the row bar 20 by the rotation of the rollers 150A and 150B (X in FIG. 3). The test signal is recorded for a predetermined length (for example, several centimeters) on a separate track of the magnetic medium 110 by the write element 31 of each thin film magnetic head element 21 while linearly moving in the positive direction (FIG. 3A). → (B)). Recording by each write element is preferably performed simultaneously.

Reproduction step: After recording in the recording step, the magnetic medium 110 is linearly moved relative to the row bar 20 in the direction opposite to that in the recording step by the rotation of the rollers 150A and 150B (in FIG. 3, a straight line in the negative X direction). 3) to return to the original position (position at the start of recording) (FIG. 3 (B) → (C)), and then hold the row bar 20 in contact with the magnetic medium 110 by the holder 130 again. Each of the inspection signals recorded while rotating the rollers 150A and 150B relatively linearly moves the magnetic medium 110 relative to the row bar 20 in the same direction as when recording (in FIG. 3, linear movement in the positive direction of X). The inspection signal is reproduced from the track by the read element 41 paired with the write element 31 that has performed recording on each track (FIG. 3 (C) → (D)). Regeneration by each read element is preferably performed simultaneously. Note that before the magnetic medium 110 is returned to the original position, the holder 130 may be moved upward to release the contact state between the magnetic medium 110 and the row bar 20. In this case, before reproduction by the read element, the holder 130 is moved downward to hold the magnetic medium 110 and the row bar 20 in contact.

Evaluation step: The characteristics of each thin film magnetic head element 21 are evaluated based on the result of reproduction in the reproduction step. Specifically, for example, the inspection signal and the reproduction signal are compared, and the characteristics are evaluated based on the output level, missing bits, and the like.

  According to the present embodiment, the following effects can be achieved.

(1) A predetermined signal (inspection signal) is recorded on the magnetic medium 110 by the write element 31 of each thin film magnetic head element 21 in a state where the row bar 20 is in contact with the flexible or flexible magnetic medium 110. Since the characteristics of each thin film magnetic head element 21 are evaluated based on the result of reproducing it with a read element, the management of the gap between the magnetic medium 110 and the thin film magnetic head element 21 becomes unnecessary. As a result, the recording characteristics of each thin film magnetic head element can be inspected in the state of a row bar in which a plurality of thin film magnetic head elements are integrated.

(2) Therefore, the throughput can be improved at a lower cost than the case of inspecting the characteristics of the thin film magnetic head element at a rate of one for each characteristic inspection apparatus, and the efficiency is high. That is, the inspection described in this embodiment is easy to introduce even if it is newly added without causing a bottleneck in relation to other processes.

(3) Furthermore, since the recording characteristics of the thin film magnetic head element can be inspected before the final inspection of the HGA, the thin film magnetic head element having a poor recording characteristic can be excluded at an early stage. The probability of remaining thin film magnetic head elements with poor recording characteristics during the final inspection can be reduced. In other words, it is advantageous in terms of cost reduction because waste of discarding expensive parts such as a suspension for a thin film magnetic head element having poor recording characteristics is reduced.

(4) Since the magnetic medium 110 having flexibility or flexibility is used, it is possible to absorb the error caused by the apparatus mechanism and the influence of the warp of the row bar 20. It becomes possible to make sure that they are brought into contact with each other. Therefore, stable signal recording (writing) can be performed from the write element of each thin film magnetic head element 21, and the reliability of the inspection is high. Incidentally, since the distance that the row bar 20 and the magnetic medium 110 contact and move relative to each other for inspection is small (for example, several centimeters), there is almost no risk of damage to the thin film magnetic head element 21 for inspection, and magnetic There is little deterioration of the medium 110.

(5) Since the inspection signal is reproduced from each track by the read element paired with the write element that performed recording on each track, and the quality of the thin film magnetic head element is judged based on the result, each thin film magnetic head It is possible to simultaneously evaluate not only the recording characteristics of the element but also the reproducing characteristics.

  Hereinafter, a specific configuration of the characteristic inspection apparatus 100 according to the present embodiment will be described.

  FIG. 4 is a perspective view illustrating a specific configuration of the characteristic inspection apparatus 100 shown in FIG. In this figure, the configuration in the case of automatically performing from the supply of the row bar 20 to the inspection and discharge is illustrated.

  The upper surface of the housing 201 forms a work space for the characteristic inspection apparatus 100. The control panel 205 is built in the housing 201 and controls the overall operation of the characteristic inspection apparatus 100. The cover 206 is for protecting the magnetic medium, and the magnetic medium 110 and the rollers 150A and 150B in FIG. The supply unit 210 transfers the uninspected row bar 20 sequentially supplied to the lower portion of the holder 130. The holder 130 can move in the horizontal direction along the movement axis 215 (X axis), and can be moved in the vertical direction by its own built-in movement mechanism. The discharge unit 220 transfers the inspected row bar 20 to the outside. The monitor 207 is for informing the user of the inspection result and the status of the entire apparatus.

  Referring to the flow of the apparatus in FIG. 4, first, the holder 130 holds the uninspected row bar 20 transferred by the supply unit 210, and moves to the right above the magnetic medium (in the cover 206) along the movement axis 215. It moves in the direction and descends (the row bar 20 is held in contact with the magnetic medium from the upper opening of the cover 206). In this state, the above-described recording process to reproduction process are performed. When the regeneration process is completed, the above-described evaluation process is performed, and the holder 130 rises and moves to the right above the discharge unit 220 along the moving shaft 215 to discharge the row bar 20.

  The present invention has been described above by taking the embodiment as an example, but it will be understood by those skilled in the art that various modifications can be made to each component and each step of the embodiment within the scope of the claims. is there. Hereinafter, modifications will be described.

  In the embodiment, the case where the magnetic medium 110 is linearly moved relative to the row bar 20 by the rotation of the rollers 150A and 150B has been described. However, in the modified example, the holder 130 is linearly moved in the X-axis direction. May be moved linearly relative to the row bar 20. Further, instead of the rollers 150A and 150B, a holding means for fixing the magnetic medium 110 with a predetermined tension is provided, which is attached to a linear motion guide and is relative to the row bar 20 by a motor via a ball screw or the like. A linear movement may be performed. Which of the magnetic medium 110 and the row bar 20 is moved can be appropriately determined according to the convenience of the device design.

  In the embodiment, the magnetic medium is linearly moved relative to the row bar. However, in a modified example, the magnetic medium is a flexible or flexible disk, and the row bar is arranged in the radial direction. It is good also as a structure which rotates.

  In the embodiment, in the reproduction process, the inspection signal is reproduced from each track by the read element paired with the write element that performed recording on each track, but in the modified example, the read element is prepared on the apparatus side. Thereby, the inspection signal may be reproduced.

  In the embodiment, the case where the inspection signals are recorded simultaneously by the respective write elements has been described, but in the modified example, the recording may be performed simultaneously by any number of two or more write elements instead of all the write elements. Alternatively, recording may be performed sequentially for each write element. The same can be said for reproduction by the read element.

  In the embodiment, the case of inspecting the characteristics of each thin film magnetic head element included in the row bar has been described. However, in the modification, only the characteristics of some thin film magnetic head elements included in the row bar may be inspected. In addition, the above-described recording process to evaluation process are performed on some thin film magnetic head elements included in the row bar to inspect the characteristics, and then the remaining thin film magnetic head elements included in the row bar are similarly inspected. May be.

1 is a conceptual perspective view illustrating the configuration of a characteristic inspection apparatus according to an embodiment of the invention. The elements on larger scale of the characteristic inspection apparatus shown by FIG. FIG. 2 is a conceptual procedure explanatory diagram showing a flow of characteristic inspection of a thin film magnetic head element by the characteristic inspection apparatus shown in FIG. 1. The perspective view which illustrates the specific structure of the characteristic inspection apparatus shown by FIG. FIG. 3 is a cross-sectional view illustrating the configuration of a thin film magnetic head element. 3 is an exemplary perspective view of a slider on which a thin film magnetic head element is formed. FIG. The conceptual explanatory drawing of the manufacturing method of a slider. It is shape explanatory drawing of HGA, (A) is a side view, (B) is a bottom view.

Explanation of symbols

20 Rover 21 Thin Film Magnetic Head Element 22 Electrode 31 Write Element 41 Read Element 100 Thin Film Magnetic Head Element Characteristic Inspection Device 110 Magnetic Media 130 Holder 150A, 150B Roller 170 Inspection Unit 201 Case 205 Control Panel 206 Cover 207 Monitor 210 Supply Unit 215 Moving shaft 220 discharge section

Claims (8)

Flexible or soft magnetic media;
A plurality of thin film magnetic head elements each having a pair of write elements and read elements are integrated in a row and integrated into a single row, and cut into individual pieces to form a plurality of sliders each having a single thin film magnetic head element. Use
Recording in which a predetermined signal is recorded on a track of the magnetic medium by a write element of the thin film magnetic head element while moving the magnetic medium relative to the row bar in a state where the row bar is in contact with the magnetic medium. Process,
A reproduction step of reproducing the predetermined signal recorded by the recording step with a read element;
A method for inspecting characteristics of the thin film magnetic head element, comprising: an evaluation process for evaluating characteristics of the thin film magnetic head element based on a reproduction result in the reproducing process.   The characteristic inspection method according to claim 1, wherein in the reproduction step, the magnetic medium is moved back relative to the row bar, and then the magnetic medium is brought into contact with the magnetic medium. The read element is paired with the write element that has performed recording on the track from the track on which the predetermined signal is recorded while moving relative to the row bar in the same direction as during recording in the recording step. A method for inspecting characteristics of a thin film magnetic head element, wherein the predetermined signal is reproduced by the method.   3. The characteristic inspection method according to claim 1, wherein the recording step records a predetermined signal on separate tracks of the magnetic medium by a write element of a plurality of thin film magnetic head elements. Characteristics inspection method.   4. The characteristic inspection method according to claim 3, wherein the reproducing step reproduces the predetermined signal recorded on each track by read elements of a plurality of thin film magnetic head elements. Inspection method. Flexible or soft magnetic media;
A plurality of thin film magnetic head elements having a pair of write elements and read elements are aligned in one row and integrated into a single piece, and a plurality of sliders each having one thin film magnetic head element are obtained by cutting into individual pieces. Holding means for holding the magnetic medium in contact with the magnetic medium;
Moving means for moving the magnetic medium relative to the row bar;
While the row bar is in contact with and held by the magnetic medium by the holding means, the magnetic medium is moved by the write means of the thin film magnetic head element while the magnetic medium is moved relative to the row bar by the moving means. An apparatus for inspecting characteristics of a thin film magnetic head element, comprising: an inspection unit that evaluates characteristics of the thin film magnetic head element based on a result of reproducing a predetermined signal recorded on a track by a read element.   6. The thin film magnetic head according to claim 5, wherein the predetermined signal is reproduced from a track on which the predetermined signal is recorded by a read element paired with a write element that has performed recording on the track. Element characteristic inspection device.   7. The characteristic inspection apparatus according to claim 5, wherein recording of a predetermined signal by a write element of a plurality of thin film magnetic head elements is performed on separate tracks of the magnetic medium.   8. The characteristic inspection apparatus according to claim 7, wherein reproduction of the predetermined signal by the read elements of a plurality of thin film magnetic head elements is performed for each track.

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