JP4157542B2 - Thin-film magnetic head inspection method - Google Patents

Description

  The present invention relates to an inspection method capable of determining the quality of a thin film magnetic head at an early stage during the manufacturing process, and more particularly to an inspection method for a thin film magnetic head having a recording head portion for perpendicular magnetic recording.

  In recent years, for example, with the improvement of the surface recording density of a magnetic recording medium such as a hard disk (hereinafter simply referred to as “recording medium”), the performance of a thin film magnetic head mounted in a magnetic recording apparatus such as a hard disk drive is required to be improved. It has been.

  As a recording method of such a thin film magnetic head, for example, a longitudinal recording method in which the direction of the signal magnetic field is set in an in-plane direction (longitudinal direction) of the recording medium, or a direction of the signal magnetic field in a direction orthogonal to the surface of the magnetic medium. A vertical recording method to be set is known.

  Although the longitudinal recording method is widely used at present, the vertical recording method is expected to be a promising alternative to the longitudinal recording method in the future if the market trend accompanying the improvement of the surface recording density of the recording medium is observed. is assumed. This is because the perpendicular recording method has an advantage that a high recording density can be secured, and in addition, a recorded recording medium is hardly affected by thermal fluctuation.

  However, in the perpendicular recording system, the track width of the main magnetic pole portion has been further narrowed in order to increase the recording density, and the influence of various external magnetic fields flowing into the main magnetic pole portion tends to become a problem. That is, the main magnetic pole portion is affected by a leakage magnetic field from the recording medium and various external magnetic fields generated in the magnetic head device, and reaches magnetic saturation or performs unexpected recording or erasing with this main magnetic pole. Such a problem may occur. For this reason, external magnetic field resistance is required to increase the recording density, and various structures for improving external magnetic field resistance have been proposed.

  In a thin film magnetic head having a recording head portion for perpendicular magnetic recording, a so-called soft magnetic underlayer disposed below the perpendicular magnetic recording layer of the magnetic recording medium facing the recording head portion is also part of the function of the magnetic head. Work as. Therefore, the specifications of the magnetic head must be considered including the relationship with the specifications of the magnetic recording medium, and the judgment of the quality of a specific magnetic head product is determined when each thin film head is completed as the final product. It is necessary to combine with a recording medium. That is, there is a need to determine whether the magnetic head is good or not by performing actual recording by combining the magnetic head product extracted as a shipping inspection and the magnetic recording medium that is the product.

JP-A 61-286863 JP-A-6-52533

  However, in the inspection of the magnetic head in the final product state, if the inspection result is determined to be defective, all the machining processes for the entire lot where the defect has occurred are wasted. Therefore, it is desirable to construct an inspection system that can perform inspection at an early stage as much as possible during processing.

  In order to solve such problems, the thin film magnetic head thin film magnetic head inspection method of the present invention has a recording head portion, an external connection electrode (bonding) in a formation region of a thin film magnetic head arranged in a matrix on a wafer. A wafer process for forming a laminated film including a pad), a wafer bar cutting process for cutting a bar-shaped magnetic head assembly in which a plurality of thin film magnetic head portions are arranged in a line on the wafer, and a wafer bar Lapping process (polishing) of the bar that polishes the cut surface after the cutting process, and the air bearing surface (ABS) polished after the lapping process, directly or via a nonmagnetic layer, pseudo perpendicular magnetic A pseudo perpendicular magnetic recording medium forming step of sequentially depositing and forming magnetic bodies of a perpendicular magnetic recording layer and a soft magnetic layer as recording media; and the wafer Thin film magnetism by performing perpendicular magnetic recording on the pseudo perpendicular magnetic recording medium, reading the magnetic domain structure of the magnetic material from the soft magnetic layer side by a magneto-optic effect, and observing the magnetic domain structure. And a magnetic head early inspection process for judging the quality of the head.

  The thin film magnetic head inspecting method of the thin film magnetic head according to the present invention includes a thin film magnetic head formed in a matrix on a wafer and a laminated film including an external connection electrode (bonding pad) in a formation region of the thin film magnetic head. A wafer process to be formed, a wafer bar cutting process for cutting out a bar-shaped magnetic head assembly in which a plurality of thin film magnetic head portions are arranged in a line on the wafer, and a cutting surface after the wafer bar cutting process A perpendicular magnetic recording layer as a quasi-perpendicular magnetic recording medium directly or via a non-magnetic layer on a lapping process (polishing) process of a bar to be polished and an air bearing surface (ABS) polished after the lapping process And a pseudo perpendicular magnetic recording medium forming step for sequentially depositing and forming a magnetic material of a soft magnetic layer, and a recording head portion formed on the wafer Thus, the magnetic field of the thin film magnetic head is judged by performing perpendicular magnetic recording on the pseudo perpendicular magnetic recording medium, reading the magnetic domain structure of the magnetic material from the soft magnetic layer side with a magnetic force microscope, and observing the magnetic domain structure. A head early inspection process.

  In a preferred embodiment of the present invention, in the wafer process, a reproducing head portion is further formed in addition to the recording head portion in a formation region of the thin film magnetic head arranged in a matrix.

  As a preferred embodiment of the present invention, perpendicular magnetic recording on the pseudo perpendicular magnetic recording medium is performed by energizing an energizing coil of the recording head formed on the wafer from an external connection electrode (bonding pad). It is configured to be

  As a preferred embodiment of the present invention, a perpendicular magnetic recording layer as a pseudo perpendicular magnetic recording medium directly on the air bearing surface (ABS) polished after the lapping treatment step in the pseudo perpendicular magnetic recording medium forming step. In addition, the magnetic material of the soft magnetic layer is sequentially deposited.

  As a preferred embodiment of the present invention, in the pseudo perpendicular magnetic recording medium forming step, a protective film as a pseudo perpendicular magnetic recording medium is formed directly on the air bearing surface (ABS) polished after the lapping treatment step. A magnetic recording layer and a soft magnetic layer are sequentially deposited and formed.

  As a preferred embodiment of the present invention, an intermediate layer is interposed between the perpendicular magnetic recording layer and the soft magnetic layer.

  As a preferred embodiment of the present invention, a nonmagnetic layer having a thickness corresponding to an air gap is formed on an air bearing surface (ABS) polished after the lapping process in the pseudo perpendicular magnetic recording medium forming process. Thus, the magnetic material of the perpendicular magnetic recording layer and the soft magnetic layer as the pseudo perpendicular magnetic recording medium are sequentially deposited and formed.

  As a preferred embodiment of the present invention, a nonmagnetic layer having a thickness corresponding to an air gap is formed on an air bearing surface (ABS) polished after the lapping process in the pseudo perpendicular magnetic recording medium forming process. Thus, a magnetic film of a protective film, a perpendicular magnetic recording layer, and a soft magnetic layer as a pseudo perpendicular magnetic recording medium is sequentially deposited and formed.

  The method for inspecting a thin film magnetic head according to the present invention includes a wafer process, a wafer bar cutting process, a lapping process (polishing) process for polishing the bar cut surface, and an air bearing surface (polished after the lapping process process). A pseudo-perpendicular magnetic recording medium forming step of sequentially depositing and forming a magnetic body of a perpendicular magnetic recording layer and a soft magnetic layer as a pseudo-perpendicular magnetic recording medium on ABS) directly or via a nonmagnetic layer; The recording head portion formed on the wafer performs perpendicular magnetic recording on the pseudo perpendicular magnetic recording medium, and the magnetic domain structure of the magnetic material is read from the soft magnetic layer side by a magneto-optical effect or a magnetic force microscope. The magnetic head is inspected to determine whether the thin film magnetic head is good or bad. It can be performed at an early stage of the manufacturing process, and if a defective head is generated, the subsequent processing process should be stopped at an early stage for the generated lot so as not to perform subsequent useless processing. It is possible to improve productivity and reduce product costs indirectly.

  The main part of the inspection method of the thin film magnetic head of the present invention is that of the air bearing surface (ABS) of the magnetic head polished by the lapping process (polishing) process for polishing the cut surface after the wafer bar cutting process. There is provided a pseudo perpendicular magnetic recording medium forming step for sequentially depositing and forming magnetic bodies of a perpendicular magnetic recording layer and a soft magnetic layer as a pseudo perpendicular magnetic recording medium, and then a recording head formed in advance on the wafer The unit performs perpendicular magnetic recording on a pseudo perpendicular magnetic recording medium, reads the magnetic domain structure of the magnetic material from the soft magnetic layer side with a magneto-optical effect or a magnetic force microscope, and observes the change of the magnetic domain structure to determine whether the thin film magnetic head is good or bad It is in the point which comprises so that it may judge.

  According to this method, the quality of the magnetic head can be determined as early as possible in the course of the manufacturing process, and if it is determined to be defective, the subsequent wasted processes for a series of related lots are stopped early. Can contribute to productivity improvement.

  Before describing the method for inspecting a thin film magnetic head of the present invention, the description of the magnetic head will be simplified so as to facilitate understanding of the inspection method of the present invention. Of course, the structure of the magnetic head itself is known.

Description of the magnetic head 6 is a schematic perspective view schematically showing one unit of the magnetic head, including the so-called slider. FIG. 7 is an enlarged cross-sectional view schematically showing only the main part of the reproducing head part (GMR element) 20 and the recording head part (inductive magnetic transducer element) 30 of the magnetic head shown in FIG. is there. In FIG. 7, the perpendicular magnetic recording medium 1 is also schematically shown in the drawing so that the operation of the magnetic head can be easily understood.

  FIG. 8 is a schematic view taken along the line AA in FIG. 7 and shows the reproducing head portion (for example, GMR element) 20 and the recording head portion (inductive magnetic transducer element for perpendicular magnetic recording) 30 of the magnetic head as an air bearing. It is drawing which showed typically the composition seen from the field (ABS). In order to facilitate understanding, only the necessary members are described.

  In order to facilitate understanding of the content of the invention, as shown in FIGS. 6 to 8, an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined. The X axis direction coincides with the moving direction of the magnetic recording medium.

  As shown in FIG. 6, one unit of the magnetic head including the slider is configured as a composite magnetic head including a slider 100 which is an aspect of the base, a reproducing head unit 20, and a recording head unit 30. Yes.

  As shown in FIG. 7, the recording head unit 30 includes a main magnetic pole 31, an auxiliary magnetic pole 35, and a current-carrying coil 39. When the current-carrying coil 39 of the recording head unit 30 is excited by flowing a current, A perpendicular magnetic field is generated between the front end and the soft magnetic layer 11 of the magnetic recording medium, whereby magnetic recording in the perpendicular direction is performed on the perpendicular magnetic recording layer 10. The magnetic flux flowing through the soft magnetic layer 11 of the magnetic recording medium returns to the auxiliary magnetic pole 35, and a magnetic circuit is formed.

  The reproducing head unit 20 is composed of, for example, a GMR element 20 for reading recorded magnetic data, and this is disposed between the magnetic shield layers 21 and 25. The reproducing head unit 20 may be another reproducing magnetic head element such as a TMR element or an AMR element instead of the GMR element.

  However, the thin film magnetic head to be inspected in the present invention may be configured to include only the recording head unit 30 without providing the reproducing head unit 20. In this embodiment, one element 20 and one element 30 are provided, but the number is not limited at all.

  As shown in FIG. 6, the slider 100 has rail portions 111, 112, and 113 on the magnetic recording medium facing surface side, and the surfaces of these rail portions constitute ABS. In the example illustrated in FIG. 6, the number of rail portions 111, 112, and 113 is three, but is not limited thereto. For example, it may have one or two rail portions, and the ABS may be a flat surface having no rail portions. Moreover, you may comprise so that various geometric shapes may be attached | subjected to ABS for a floating characteristic improvement etc.

  As shown in FIG. 6, the reproducing head unit 20 and the recording head unit 30 are provided on the air outflow end TR side of the rail unit 113. The recording medium moving direction coincides with the X-axis direction in the figure, and coincides with the outflow direction of air that moves when the magnetic recording medium moves at high speed. Air enters from the inflow end LE and flows out from the outflow end TR. Bonding pads 95 a and 95 b connected to the reproducing head unit 20 and bonding pads 95 c and 95 d connected to the recording head unit 30 are provided on the end surface of the air outflow end portion TR of the slider 100.

Description of Thin Film Magnetic Head Inspection Method of the Present Invention Next, the thin film magnetic head inspection method of the present invention will be described in detail.

  FIG. 1 is a flowchart showing a preferred example of the method for inspecting a thin film magnetic head of the present invention. FIG. 2 is a schematic perspective view schematically showing a bar cutting process after the wafer process. FIG. 3 is a manufacturing schematic diagram schematically showing a situation from assembling a magnetic head formed and processed from a wafer.

  Hereinafter, it demonstrates sequentially in order of a process.

[Wafer process]
Using the prepared wafer, a matrix-shaped thin film magnetic head formation region is formed on the wafer so that a large number of heads can be obtained (address formation). Thereafter, a wafer process (step S1) for forming a laminated film including a recording head portion, a reproducing head portion, and external connection electrodes (bonding pads) in the formation region of each thin film magnetic head is performed.

That is, a wafer made of Al ₂ O ₃ —TiC or the like to be a ceramic substrate is prepared, and each element is formed in a matrix-like formation region of a large number of magnetic head elements on the wafer by using a thin film formation technique or the like. A laminated film and external connection electrodes (bonding pads) and the like are formed.

  FIG. 2A shows the wafer 115 that has undergone this wafer process. However, in FIG. 2A, elements formed on the wafer 115 are omitted, and only the regions R of the individual magnetic head elements arranged in a matrix are shown.

[Wafer bar cutting process]
Next, the wafer 115 shown in FIG. 2A is cut, and each bar (bar-shaped magnetic head assembly) 116 in which the constituent parts of a plurality of magnetic heads are arranged in a line on the base is replaced with a diamond cutter or the like. A wafer bar cutting process is performed (step S2).

  FIG. 2B shows this bar 116. The upper surface of the bar 116 parallel to the XZ plane in FIG. 2B is the ABS side surface of the magnetic head, and the end surface of the laminated film forming each element as shown in FIG. In addition, bonding pads 95a to 95d and the like in FIG. 6 appear on the surface that is parallel to the YZ plane in FIG. However, they are not shown in the drawing of FIG.

[Lapping (polishing) process]
Next, a lapping process (polishing) process is performed on the bar 116 shown in FIG. 2B to polish the cut surface after the wafer bar cutting process (step S3). That is, in order to set the so-called throat height of the recording head portion, the so-called MR height of the reproducing head portion, etc., a step of lapping (polishing) the ABS is provided. In this process, for example, the bar 116 is set on a fixed jig, pressed against the surface plate, a suspension containing diamond abrasive grains is dropped, and the surface plate is rotated to polish the ABS.

  After such a lapping process (polishing) process, it is desirable to provide a process for cleaning the bar 116 after the polishing process. As a method of cleaning, for example, oil may be wiped off with alcohol or ultrasonic cleaning may be performed. Furthermore, it is desirable to provide a cleaning process for cleaning the polished surface by sputter etching or ion beam etching. However, these washing steps and cleaning steps are not necessarily required, and a pseudo perpendicular magnetic recording medium forming step described later may be performed after the lapping process (polishing) step.

[Pseudo perpendicular magnetic recording medium forming process]
On the air bearing surface (ABS) polished after the lapping process, magnetic materials of the perpendicular magnetic recording layer and the soft magnetic layer as a pseudo perpendicular magnetic recording medium are sequentially deposited directly or via a nonmagnetic layer. A pseudo perpendicular magnetic recording medium forming step is provided (step S4).

  The configuration of the quasi-perpendicular magnetic recording medium deposited and formed substantially directly on the air bearing surface (ABS) is the same as or similar to the configuration of a generally used perpendicular magnetic recording medium. Therefore, the structure of the general perpendicular magnetic recording medium 1 shown in FIG. 7 will be briefly described so that the pseudo perpendicular magnetic recording medium forming process can be easily understood.

Description of Perpendicular Magnetic Recording Medium As shown in FIG. 7, the structure in the vicinity of the data track in the perpendicular magnetic recording medium 1 includes a substrate 15, an alignment layer 14 formed on the substrate 15, and an alignment layer 14. A soft magnetic layer 11 formed on the intermediate layer 12, an intermediate layer 12 formed on the soft magnetic layer 11, a perpendicular magnetic recording layer 10 formed on the intermediate layer 12, and a protection formed thereon. Layer 13.

  As the substrate 15, a glass substrate, a NiP-coated aluminum alloy substrate, a Si substrate, or the like is preferably used. As the alignment layer 14, for example, an antiferromagnetic material such as PtMn for applying a magnetic anisotropic magnetic field in the track width direction of the soft magnetic layer 11 can be used. In addition, a nonmagnetic alloy for controlling the orientation may be used.

  Examples of the soft magnetic layer 11 include NiFe, Fe-based alloy, CoNiFe-based alloy, Co-based amorphous alloy, soft magnetic / non-magnetic multilayer film, and soft magnetic ferrite. The soft magnetic layer 11 is a so-called soft magnetic backing layer.

  The intermediate layer 12 is provided, for example, to control the perpendicular magnetic anisotropy and crystal grain size of the perpendicular magnetic recording layer formed on the intermediate layer. For example, Cr, Ti, Ru, CoTi nonmagnetic alloy Is used. In addition, a nonmagnetic metal, an alloy, or an alloy having a low magnetic permeability that functions similarly may be used.

As the perpendicular magnetic recording layer (data track) 10, a medium in which ferromagnetic particles such as CoPt are contained in a matrix in a SiO ₂ oxide material, a CoCr alloy, a FePt alloy, or a Co / Pd alloy is used. An artificial lattice type multilayer alloy or the like is preferably used.

  A protective layer 13 such as DLC or carbon is usually formed on the surface of the perpendicular magnetic recording layer (data track) 10 by using a CVD method or the like.

Although not shown in FIG. 7, in the perpendicular magnetic recording medium 1, the perpendicular magnetic recording layer is divided into a number of recording elements in a predetermined uneven pattern on the substrate, and the perpendicular magnetic recording layer is guarded by a nonmagnetic layer. It may be a so-called discrete type magnetic recording medium. As the material for the nonmagnetic layer, for example, nonmagnetic oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ and ferrite, nitrides such as AlN, and carbides such as SiC are used.

  As described above, the explanation about the configuration of the perpendicular magnetic recording medium 1 is finished, and the explanation about the formation of the quasi-perpendicular magnetic recording medium, which is the main process of the present invention, in a situation where the configuration can be understood. The formation process will be described below.

[ Explanation regarding formation of pseudo perpendicular magnetic recording medium on ABS ]
A magnetic material of a perpendicular magnetic recording layer and a soft magnetic layer as a pseudo perpendicular magnetic recording medium are sequentially deposited on an air bearing surface (ABS) polished after the lapping process directly or via a nonmagnetic layer. A pseudo perpendicular magnetic recording medium forming step is performed (step S4).

  That is, as shown in FIG. 4, the perpendicular magnetic recording layer 10 and the soft magnetic layer 11 as a pseudo perpendicular magnetic recording medium are sequentially deposited and formed directly on the air bearing surface (ABS) of the magnetic head polished. Is done. For the deposition of each layer, for example, a vacuum thin film forming technique such as sputtering may be used. Regarding the material and thickness of the perpendicular magnetic recording layer 10 and the soft magnetic layer 11 to be formed, it is preferable to use the same material and thickness as the actual product as much as possible.

  Further, as shown in FIG. 5, a protective layer 13, a perpendicular magnetic recording layer 10, an intermediate layer 12, and a soft layer are formed on the air bearing surface (ABS) as a pseudo perpendicular magnetic recording medium so as to be closer to an actual product. It is also a preferable aspect that the magnetic layer 11 is sequentially deposited.

  Further, in order to make it as close as possible to the actual magnetic recording state, a nonmagnetic layer (not shown) having a thickness corresponding to an air gap between the air bearing surface (ABS) and the perpendicular magnetic recording layer 10 in FIG. Or a nonmagnetic layer (not shown) having a thickness corresponding to the air gap is formed between the air bearing surface (ABS) and the protective layer 13 in FIG. You may do it.

[Magnetic head early inspection process]
Next, perpendicular magnetic recording is performed on the pseudo perpendicular magnetic recording medium by the recording head unit 30 formed on the wafer, and the magnetic domain structure of the magnetic bodies 10 and 11 is observed from the soft magnetic layer 11 side by a magneto-optical effect or a magnetic force microscope. A magnetic head early inspection process is performed in which the quality of the thin film magnetic head is judged by reading and observing the change in the magnetic domain structure (step S5).

  That is, after a pseudo perpendicular magnetic recording medium is formed on the ABS side which is the recording / reproducing surface of the magnetic head, magnetic recording is actually performed on the deposited pseudo perpendicular magnetic recording medium to judge whether the magnetic head is good or bad. . Perpendicular magnetic recording on the quasi-perpendicular magnetic recording medium can be performed by energizing the energizing coil 39 of the recording head unit 30 formed on the wafer from an external connection electrode (bonding pad).

  Magneto-optic effect (magneto-optic Kerr effect) is a phenomenon in which the polarization state and reflectivity of reflected light change depending on magnetization when light is incident on a substance. A magnetic force microscope is a cantilever that is coated with a magnetic film. Use it and scan it on the sample. Thus, when a magnetic potential is generated on a sample, an apparatus capable of obtaining three-dimensional magnetic information by generating an attractive force or a repulsive force on the cantilever.

  The thin-film magnetic head that is the object of the inspection method of the present invention is one that has been extracted as a sample for inspection from a series of in-process lots that have undergone wafer bar cutting and lapping (polishing) processes. is there.

  When the inspection is completed and the magnetic head operates normally and is determined to be “good”, the process can proceed to the next processing process. If it is determined to be “defective”, the subsequent processing is stopped for all of the series of lots that are the population of the extracted inspection samples.

  A series of lots determined as “good” are transferred to the next processing process.

[Formation of protective film on ABS]
Next, a process of forming a protective film is provided on the ABS side surface of the bar 116 (step S6). A cleaning process (sputter etching or ion beam etching) may be provided before forming the protective film. Furthermore, it is also a preferable aspect to provide a step of forming a base film containing silicon as a main component before forming the protective film.

  A suitable example of the protective film is a diamond-like carbon film (DCL film) that is excellent in durability and corrosion resistance. The thickness of the protective film is about 1 to 30 nm.

[Rail etching process]
After the protective film is formed, a step of selectively etching regions other than the rails 111 and 112 regions on the ABS side surface of the bar 116 to form the rails 111 and 112 is provided (step S7).

[Process of separating into individual magnetic heads]
Finally, a step of cutting by machining to separate the bar 116 into individual magnetic heads is provided (step S8). As a result, one unit of a so-called magnetic head is completed (see step (III) in FIG. 3).

  The magnetic head alone thus formed is incorporated into the head gimbal assembly by the head assembling process (see process (IV) in FIG. 3).

A 6-inch Al ₂ O ₃ —TiC wafer was prepared, and a matrix-shaped thin film magnetic head formation region was formed on the wafer so that a large number of heads could be obtained. Next, a laminated film was formed in each of these regions to form a recording head portion for perpendicular magnetic recording, a reproducing head portion (spin valve GMR multilayer film), and an external connection electrode (bonding pad).

  Next, the wafer was cut, and each bar (bar-shaped magnetic head assembly) in which the constituent parts of a plurality of magnetic heads were arranged in a line on the substrate was cut out with a diamond cutter.

  Next, the cut surface of the cut bar was polished to set the throat height of the recording head.

  After cleaning the polished bar, a perpendicular magnetic recording layer and a soft magnetic layer as a pseudo perpendicular magnetic recording medium were sequentially deposited directly on the polished air bearing surface (ABS). For the perpendicular magnetic recording layer, a CoCrPt material was used, and its thickness was 20 nm. As the soft magnetic layer, a NiFe material was used and its thickness was 100 nm.

  Next, perpendicular magnetic recording was performed on the perpendicular magnetic recording layer of the pseudo perpendicular magnetic recording medium by energizing the energizing coil of the recording head formed on the wafer from the external connection electrode.

  Changes in the magnetic domain structure of the magnetic material before and after perpendicular magnetic recording were read from the soft magnetic layer side with a magnetic force microscope.

  Intentionally, magnetic head samples (so-called defective samples) that deviate significantly from the normal thin-film magnetic head specifications were produced and the above experiment was conducted. The magnetic domain structure of the magnetic material before and after perpendicular recording was recorded. The change was read from the soft magnetic layer side. Then, the domain wall was observed after energization in a place where the domain wall was not observed before energization. When the location where the domain wall was observed was confirmed by overlapping with the ABS form of the recording head unit, the magnetic flux was concentrated on the end E of the auxiliary magnetic pole 35 (write shield 35) shown in FIG. It was confirmed that (erasure) occurred.

  In addition, when the perpendicular magnetic recording layer, which is one of the constituent elements of the pseudo perpendicular magnetic recording medium, is not provided (that is, only the soft magnetic layer is used), the change of the domain wall in the above experiment could not be confirmed. Therefore, in carrying out the method of the present invention, it was confirmed that the perpendicular magnetic recording layer is an essential constituent element of the pseudo perpendicular magnetic recording medium. The same applies to the soft magnetic layer.

  Even when the observation by the magnetic force microscope is replaced with the observation by the magneto-optical effect, the change in the magnetic domain structure of the magnetic material before the direct magnetic recording and after the perpendicular recording is similarly observed on the soft magnetic layer side. It was confirmed that it can be read from.

  The effects of the present invention are clear from the above results.

  That is, the thin film magnetic head inspection method of the present invention includes a wafer process, a wafer bar cutting process, a lapping process (polishing) process for polishing a bar cutting surface, and an air bearing polished after the lapping process. A quasi-perpendicular magnetic recording medium forming step of sequentially depositing and forming magnetic bodies of a perpendicular magnetic recording layer and a soft magnetic layer as a quasi-perpendicular magnetic recording medium directly or via a nonmagnetic layer on the surface (ABS); Then, the recording head portion formed on the wafer performs perpendicular magnetic recording on the pseudo perpendicular magnetic recording medium, and reads the magnetic domain structure of the magnetic material from the soft magnetic layer side by a magneto-optical effect or a magnetic force microscope, Since the magnetic head early inspection process for determining the quality of the thin film magnetic head by observing the change in the magnetic domain structure is provided, the magnetic head Inspection can be performed at an early stage of the manufacturing process, and if a defective head occurs, the subsequent processing process is stopped early for the generated lot so that the subsequent unnecessary processing is not performed. It is possible to improve productivity and reduce product costs indirectly.

  The present invention can be used in the industry of hard disk devices including a thin-film magnetic head having an inductive magnetic transducer for recording and a magnetoresistive element for reproduction.

FIG. 1 is a flowchart showing a preferred example of the method for inspecting a thin film magnetic head of the present invention. FIG. 2 is a schematic perspective view schematically showing a bar cutting process after the wafer process. FIG. 3 is a manufacturing schematic diagram schematically showing a situation from assembling a magnetic head formed and processed from a wafer. FIG. 4 is a cross-sectional view showing a state in which a perpendicular magnetic recording layer and a soft magnetic layer as a pseudo perpendicular magnetic recording medium are sequentially deposited on an air bearing surface (ABS) of a polished magnetic head. It is. FIG. 5 is a cross-sectional view showing a modification of FIG. FIG. 6 is a schematic perspective view schematically showing one unit of a magnetic head including a so-called slider. FIG. 7 is an enlarged sectional view schematically showing only the main part of the reproducing head portion and the recording head portion of the magnetic head shown in FIG. FIG. 8 is a schematic view taken along the line AA in FIG. 7, and schematically shows the configuration of the reproducing head portion and the recording head portion of the magnetic head as viewed from the air bearing surface (ABS).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Perpendicular magnetic recording medium 10 ... Perpendicular magnetic recording layer 11 ... Soft magnetic layer 20 ... Reproduction head part 21, 25 ... Magnetic shield layer 30 ... Recording head part 31 ... Main magnetic pole 35 ... Auxiliary magnetic pole 39 ... Current-carrying coil 100 ... Slider 115 ... wafer 116 ... bar (bar-shaped magnetic head assembly)

Claims (10)

A wafer process for forming a laminated film including a recording head portion and external connection electrodes (bonding pads) in a formation region of a thin film magnetic head arranged in a matrix on the wafer;
A wafer bar cutting step of cutting out a bar-shaped magnetic head assembly in which a plurality of thin film magnetic head portions are arranged in a line on the wafer;
A lapping process (polishing) process for polishing the cut surface after the cutting process of the wafer bar;
A magnetic material of a perpendicular magnetic recording layer and a soft magnetic layer as a pseudo perpendicular magnetic recording medium are sequentially deposited on an air bearing surface (ABS) polished after the lapping process directly or via a nonmagnetic layer. A pseudo perpendicular magnetic recording medium forming step,
Performing perpendicular magnetic recording on the pseudo-perpendicular magnetic recording medium by a recording head portion formed on the wafer, reading the magnetic domain structure of the magnetic material from the soft magnetic layer side by a magneto-optic effect, and observing the magnetic domain structure; And a magnetic head early inspection process for judging whether the thin film magnetic head is good or bad. A wafer process for forming a laminated film including a recording head portion and external connection electrodes (bonding pads) in a formation region of a thin film magnetic head arranged in a matrix on the wafer;
A wafer bar cutting step of cutting out a bar-shaped magnetic head assembly in which a plurality of thin film magnetic head portions are arranged in a line on the wafer;
A lapping process (polishing) process for polishing the cut surface after the cutting process of the wafer bar;
On the air bearing surface (ABS) that has been polished after the lapping process, the magnetic material of the perpendicular magnetic recording layer and the soft magnetic layer as a pseudo-perpendicular magnetic recording medium are sequentially deposited directly or via a nonmagnetic layer. A pseudo perpendicular magnetic recording medium forming step,
Performing perpendicular magnetic recording on the pseudo-perpendicular magnetic recording medium by a recording head portion formed on the wafer, reading the magnetic domain structure of the magnetic material from the soft magnetic layer side with a magnetic force microscope, and observing the magnetic domain structure; And a magnetic head early inspection process for judging whether the thin film magnetic head is good or bad.   3. The inspection of a thin film magnetic head according to claim 1, wherein a reproducing head portion is further formed in addition to the recording head portion in a formation region of the thin film magnetic head arranged in a matrix in the wafer process. Method.   4. Perpendicular magnetic recording on the pseudo perpendicular magnetic recording medium is performed by energizing an energizing coil of a recording head formed on the wafer from an external connection electrode (bonding pad). 4. A method for inspecting a thin film magnetic head according to any one of the above   In the quasi-perpendicular magnetic recording medium forming step, the magnetic bodies of the perpendicular magnetic recording layer and the soft magnetic layer as the quasi-perpendicular magnetic recording medium are sequentially formed directly on the air bearing surface (ABS) polished after the lapping process step. 5. The inspection method for a thin film magnetic head according to claim 1, wherein the thin film magnetic head is deposited.   In the quasi-perpendicular magnetic recording medium forming step, the magnetic properties of the protective film, the perpendicular magnetic recording layer, and the soft magnetic layer as the quasi-perpendicular magnetic recording medium are directly formed on the air bearing surface (ABS) polished after the lapping step. 5. The method for inspecting a thin film magnetic head according to claim 1, wherein the body is sequentially deposited.   7. A method for inspecting a thin film magnetic head according to claim 5, wherein an intermediate layer is interposed between the perpendicular magnetic recording layer and the soft magnetic layer.   In the quasi-perpendicular magnetic recording medium forming step, a quasi-perpendicular magnetic recording medium is formed on the air bearing surface (ABS) polished after the lapping process step via a nonmagnetic layer having a thickness corresponding to an air gap. 5. A method for inspecting a thin film magnetic head according to claim 1, wherein the magnetic bodies of the perpendicular magnetic recording layer and the soft magnetic layer are sequentially deposited.   In the quasi-perpendicular magnetic recording medium forming step, a quasi-perpendicular magnetic recording medium is formed on the air bearing surface (ABS) polished after the lapping process step via a nonmagnetic layer having a thickness corresponding to an air gap. 5. A method of inspecting a thin film magnetic head according to claim 1, wherein the protective film, the perpendicular magnetic recording layer, and the magnetic material of the soft magnetic layer are sequentially deposited.   The thin film magnetic head inspection method according to claim 8 or 9, wherein an intermediate layer is interposed between the perpendicular magnetic recording layer and the soft magnetic layer.

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