JP2005038553A - Magnetic head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a laminated magnetic head having no track shifting with a narrow track width, and excellent characteristics even in a high-frequency band and suited as a private/broadcast digital VTR or a tape streamer. <P>SOLUTION: After a pair of core halves are bonded into one, at least one of both ends of a track is removed by microboring processing from a sliding surface side, and a track width is regulated. By this method, a magnetic layer thickness is set as in the conventional case, and a track part alone is reduced to a desired width. Thus, the problem of characteristic deterioration by magnetic layer thinning, and characteristics are improved by a magnetic flux converging effect. Moreoever, since no track shifting occurs, recording fringes are removed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laminated magnetic head suitable for consumer / broadcasting digital VTRs and tape streamers having a narrow track width and excellent characteristics even in a high-frequency band, and a method of manufacturing the same.

  In recent years, in the field of digital VTR and other data storage, the amount of information handled as typified by high-definition image data has rapidly increased, and development of devices that increase the recording capacity per magnetic tape and increase the transfer rate has been active. It is. A magnetic head used in these devices is required to have a high recording ability using a high saturation magnetic flux density material and to have excellent characteristics even in a high frequency region of 20 MHz to 100 MHz. On the other hand, a laminated magnetic head is formed by alternately depositing a metal magnetic film and an insulating film such as an amorphous structure magnetic film containing Co as a main component and a fine crystal structure magnetic film containing Fe as a main component. It reduces eddy current loss and has excellent high frequency characteristics. Furthermore, a laminated film was developed in which the magnetic anisotropy of adjacent metal magnetic films across the insulating layer was alternately controlled to dramatically increase the high-frequency permeability as a whole film. A laminated magnetic head having a structure sandwiched between non-magnetic substrates having wear resistance that can withstand high-speed rotation of the head has been developed (for example, see Patent Document 1).

FIG. 6A shows a configuration diagram of such a conventional laminated magnetic head, and FIG. 6B shows an enlarged view of a track portion arranged on the sliding surface with the tape. 6A, the laminated magnetic head has a structure in which the laminated film 4 in which the metal magnetic films 2 and the insulating films 3 are alternately laminated as described above is sandwiched by the nonmagnetic substrate 1 from both sides. It is comprised with the mold glass 7 with which the groove | channel was filled. In FIG. 6B, the track portion is a state in which the laminated films of the left and right core halves A and B are in contact with each other through the magnetic gap 5 made of a nonmagnetic material. The effective track width is t. At present, in order to improve the recording density, a narrow track having a track width t of 10 to 15 micrometers or less is demanded. On the other hand, in the case of this laminated magnetic head, the smaller the film thickness of the laminated film, the more magnetic There is a problem that the resistance increases, and the characteristics particularly in the high frequency region are significantly deteriorated.
As a technique for solving this, there is a method of restricting a laminated film having a certain film thickness to an arbitrary track width by grinding with a dicing saw or the like in a step before joining a pair of core halves. (For example, refer to Patent Document 2).
JP-A-7-130536 JP-A-5-314422

  According to this method, it is possible to realize a narrow track while the film thickness of the laminated film remains the same as before, but since the pair of core halves are joined and integrated after the track width restriction, the deviation amount δ due to the limit of the butt accuracy is Same as before. Therefore, as the track becomes narrower, the relative ratio of the deviation amount δ to the track width t increases, and the adjacent track information on the tape is erroneously erased due to the deterioration of the track width accuracy or the leakage magnetic flux leaking from the deviation portion, that is, the fringe. Problems such as the problem were not solved.

  In order to achieve the above object, the present invention regulates the track width by removing at least one of both ends of the track by fine drilling from the sliding surface side after the pair of core halves are joined and integrated. If this method is used, the film thickness of the laminated film, which is the magnetic path, is configured as it is, and only the track part is narrowed down to the desired width. The characteristics can be improved by the effect. Further, since the track deviation δ is eliminated, the recording fringe due to the leakage magnetic flux from the deviation portion can be eliminated. When a signal is overwritten on a tape with a wide magnetic head and recording is performed at a pitch narrower than the track width of the magnetic head, the track end on the overwritten side may be misaligned. It is only necessary to regulate at least one of both ends of the track.

  As a means for micro-drilling processing in the multilayer head, it is optimal to use a micro tool formed by discharge truing a sintered body of fine particle diamond or a tool in which diamond is electrodeposited (electroformed). Both have excellent wear resistance, the former can be formed into a free shape by discharge truing, and the latter has the advantage of having excellent cutting properties. Drilling while rotating these tools from the head sliding surface direction to the depth direction, or processing direction on the table that holds the core block that is the workpiece regardless of whether the tool is rotating or not rotating Drill a hole while applying vibration to it. By this method, it is possible to produce a laminated magnetic head suitable for consumer / broadcasting digital VTRs and tape streamers having narrow track width, no track deviation, and excellent characteristics in a high frequency band.

  According to the first aspect of the present invention, a metal magnetic film sandwiched between nonmagnetic substrates is abutted through a magnetic gap made of a nonmagnetic material on a sliding surface of a laminated magnetic head having a main magnetic path. The magnetic head is characterized in that at least one of both end portions of the track is removed by fine drilling from the sliding surface side and the track width is regulated, and the film thickness of the laminated film that is a magnetic path Therefore, it is possible to solve the problem of characteristic deterioration due to the magnetic layer thinning and to improve the characteristic by the effect of narrowing the magnetic flux. Further, since the track shift is eliminated, it is possible to eliminate the recording fringe due to the leakage magnetic flux, which has been a problem when overwriting a signal on the tape.

  The invention according to claim 2 of the present invention is characterized in that the shape of the fine hole in the sliding surface is a substantially circular shape, a substantially elliptical shape, a substantially trapezoidal shape, or a part of any of them. Since it is a magnetic head and has a shape that effectively narrows the flow of magnetic flux, a greater improvement in characteristics is realized.

  According to a third aspect of the present invention, the dimensional ratio between the track width t and the total thickness T of the metal magnetic film is 0.05 ≦ t / T <1. Since t / T is proportional to the magnetic resistance of the core, the smaller the value, the better the characteristics can be expected. Regarding the thickness T of the laminated film, the upper limit of T is about 30 μm from the viewpoint of damage caused by the film stress on the substrate and uneven wear during tape running, while the minimum track width t that can withstand the processing load is about 1.5 μm. Therefore, 0.05 ≦ t / T is set as an appropriate range.

  The invention according to claim 4 of the present invention is characterized in that the metal magnetic film has a non-crystalline structure with Co as a main component, or a fine crystal structure with Fe as a main component and a particle size of 50 nanometers or less. 4. The magnetic head according to claim 1, wherein the magnetic head has a laminated structure with an insulating layer and has an excellent magnetic permeability even in a high frequency region. A magnetic head having excellent high frequency characteristics can be manufactured by using a metal magnetic film showing

  According to a fifth aspect of the present invention, in the method of manufacturing a laminated magnetic head in which a metal magnetic film sandwiched between nonmagnetic substrates forms a main magnetic path, a pair of nonmagnetic substrates and metal magnetic films laminated alternately. A step of joining and integrating the core block through a magnetic gap made of a non-magnetic material, a step of forming a microhole in at least one of both ends of the track from the sliding surface side of the core block, A method of manufacturing a magnetic head including a step of melt-filling mold glass, suitable for consumer / broadcasting digital VTRs and tape streamers having narrow track width, no track deviation, and excellent characteristics in a high frequency band. A multilayer magnetic head can be manufactured.

  A sixth aspect of the present invention is the magnetic head according to the fifth aspect, wherein a diamond sintered body or an electrodeposition (electroforming) tool is used as the tool for forming the fine hole. This is a manufacturing method that enables machining from the sliding surface side by using a tool with excellent machinability, ensuring the desired dimensional accuracy without causing cracks or chipping in the core block that is the workpiece. Can be processed.

  The invention according to claim 7 of the present invention is the method of manufacturing a magnetic head according to claim 6, wherein the diamond has a particle size of 30 micrometers or less. By performing precise grinding, it is possible to suppress the generation of a work-affected layer on the processed surface of the metal magnetic film, and to obtain a mirror surface or a processed surface roughness close thereto. Therefore, the track width accuracy is further improved and the processing stress does not affect the characteristics.

  The invention according to claim 8 of the present invention is characterized in that when forming the fine holes, the table holding the core block as a workpiece is drilled while applying vibration in the processing direction. The method of manufacturing a magnetic head according to any one of 5 to 7, wherein the work of the diamond abrasive grains is increased by vibrating the core block in the processing direction, and the discharge of chips is promoted and the processing water is By improving the quality, seizure or the like can be suppressed, and as a result, it contributes to a dramatic improvement in grindability and a longer tool life.

  The invention according to claim 9 of the present invention uses a multi-tool in which at least two tools are combined as the tool for forming the fine hole. This is a method for manufacturing a magnetic head, and if two tools with a gap corresponding to the desired track width are used, machining to a constant track width is possible regardless of the mechanical accuracy on the tool holding side or machining table side. can do. For this reason, the track width accuracy is improved and, for example, in the case of two multi tools, the machining tact can be halved.

  As described above, according to the present invention, a multilayer magnetic head suitable for a consumer / broadcasting digital VTR or a tape streamer having a narrow track width, no track deviation, and excellent characteristics in a high frequency band is realized. be able to.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.

(Embodiment 1)
FIG. 1A is a diagram showing the configuration of the magnetic head according to the embodiment of the first invention, and FIG. 1B is an enlarged view of a track portion arranged on the sliding surface with the tape. is there. In FIG. 1 (a), a pair of core halves sandwiching a laminated film 4 in which metal magnetic films 2 and insulating films 3 are alternately deposited from both sides via a magnetic gap 5 made of a nonmagnetic material. It is joined together. In FIG. 1 (b), the laminated film 4 of the left and right core halves A and B originally has a track deviation of δ, but is removed by circular fine holes formed at both ends of the track, and the thickness T of the laminated film The effective track width at this time is t. The fine holes and the winding grooves are filled with the same low melting point glass 7, but separate glasses may be used.

In this embodiment, an FeTaN magnetic film is used as the metal magnetic film, Al ₂ O ₃ is used as the insulating film, a magnesium titanate substrate is used as the nonmagnetic substrate, the FeTaN magnetic film is 2.4 micrometers, and Al ₂ O ₃ is 0.1 A laminated film of about 15 micrometers is produced by alternately laminating six layers of micrometers, and the effective track width t is set to 8 micrometers by the track width restriction by the fine holes. The characteristics of this laminated magnetic head are improved by about 3 dB at a measurement frequency of 60 MHz compared to the conventional laminated magnetic head having a track width of 8 micrometers, and are excellent in a high frequency band with a narrow track width and no track deviation. A multilayer magnetic head suitable for consumer / broadcasting digital VTRs and tape streamers having characteristics was realized.

(Embodiment 2)
Next, FIGS. 2 to 5 show the manufacturing process of the actually manufactured laminated magnetic head. First, as shown in FIG. 2A, a laminated film 4 in which metal magnetic films 2 and insulating films 3 are alternately deposited is formed on a mirror-polished nonmagnetic substrate 1 by sputtering. A laminated block 8 as shown in FIG. 2C was produced by adhering 15 sheets through a bonding glass layer as shown in b).

  Next, in FIG. 3A, a laminated plate 9 with a predetermined azimuth is cut out from the laminated block 8 using a wire saw, and a winding window groove is formed on one laminated plate by grinding stone as shown in FIG. 3B. 10 was formed. Thereafter, a process of mirror polishing the abutting surfaces of the pair of laminated plates to a predetermined surface roughness, a process of forming a nonmagnetic gap material or adhesive glass, and a process of adjusting the track of the pair of laminated plates 9 are performed. Then, heat treatment was carried out while maintaining pressure as shown in FIG. 3C, and a bonding plate 11 that was gap-bonded as shown in FIG. 3D was produced.

  After cutting out the core block 12 from the joining plate 11, as shown in FIG. 3 (e), the micro-hole processing was performed to the depth penetrating from the sliding surface side to the winding window, thereby regulating the track width. As shown in FIG. 4A, the tool 13 used at this time is a diamond sintered body having a particle diameter of about 3 micrometers formed by discharge truing so that the cross-sectional shape thereof becomes a substantially trapezoid. The table 20 to which the core block is fixed was subjected to vibration having a frequency of 10 kHz and an amplitude of 20 micrometers in the processing direction. The tool was non-rotating and the processing speed was 3 micrometers / second in the depth direction. In this embodiment, the table side, that is, the core block is vibrated, but the tool side may be vibrated.

  Next, as shown in FIG. 5A, the mold glass 7 is melt-filled into the fine holes and the winding grooves, and then subjected to predetermined outer shape processing and chip forming processing, whereby the laminated mold shown in FIG. A magnetic head could be fabricated. It was confirmed that this laminated magnetic head has a narrow track width, no track deviation, and excellent characteristics even in a high frequency band.

In the first embodiment, Al ₂ O ₃ is used as the insulating film, but the same effect can be obtained by using other insulating materials such as SiO ₂ or high-resistance oxide magnetic materials such as FeMg. In the first embodiment, the magnesium titanate substrate is used as the nonmagnetic substrate. However, the same effect can be obtained by using a nonmagnetic substrate such as calcium titanate or nonmagnetic single crystal ferrite. Further, the film thickness and the number of stacked layers of the metal magnetic film and the insulating film shown in the first embodiment are not limited to this.

1 is a schematic diagram showing a laminated magnetic head according to a first embodiment of the present invention. Schematic showing a method of manufacturing a laminated magnetic head according to a second embodiment of the present invention. Schematic showing a method of manufacturing a laminated magnetic head according to a second embodiment of the present invention. Schematic showing a method of manufacturing a laminated magnetic head according to a second embodiment of the present invention. Schematic showing a method of manufacturing a laminated magnetic head according to a second embodiment of the present invention. Schematic diagram showing a conventional laminated magnetic head

Explanation of symbols

A, B Core half 1 Non-magnetic substrate 2 Metal magnetic film 3 Insulating film 4 Laminated film 5 Magnetic gap 6 Winding window 7 Molded glass 8 Laminated block 9 Laminated plate 10 Winding window groove 11 Joining plate 12 Core block 13 Diamond tool 20 tables

Claims (9)

At least one of both ends of the track abutted through a magnetic gap made of a nonmagnetic material slides on the sliding surface of the laminated magnetic head in which the metal magnetic film sandwiched between the nonmagnetic substrates forms the main magnetic path. A magnetic head which is removed by fine drilling from the surface side and the track width is regulated. 2. The magnetic head according to claim 1, wherein the shape of the fine hole in the sliding surface is a substantially circular shape, a substantially elliptical shape, a substantially trapezoidal shape, or a part of any one of them. 3. The magnetic head according to claim 1, wherein a dimensional ratio between the track width t and the total thickness T of the metal magnetic film is 0.05 ≦ t / T <1. The metal magnetic film is either a metal magnetic film having an amorphous structure containing Co as a main component, or a metal magnetic film having a fine crystal structure containing Fe as a main component and a particle size of 50 nanometers or less, and is insulated. 4. The magnetic head according to claim 1, wherein the magnetic head has a laminated structure with layers. In a method of manufacturing a laminated magnetic head in which a metal magnetic film sandwiched between nonmagnetic substrates forms a main magnetic path, a pair of core blocks in which nonmagnetic substrates and metal magnetic films are alternately stacked have a magnetic gap made of a nonmagnetic material. A magnetic head including a step of joining and integrating, a step of forming fine holes in at least one of both ends of the track from the sliding surface side of the core block, and a step of melt-filling the fine holes with mold glass Manufacturing method. 6. A method of manufacturing a magnetic head according to claim 5, wherein a diamond sintered body or an electrodeposition (electroforming) tool is used as the tool for forming the fine holes. 7. The method of manufacturing a magnetic head according to claim 6, wherein the diamond has a particle size of 30 micrometers or less. 8. The magnetic head according to claim 5, wherein, when forming the fine hole, a hole is formed while applying vibration in a processing direction to a table that holds a core block that is a workpiece. Production method. The method of manufacturing a magnetic head according to claim 5, wherein a multi-tool in which at least two tools are combined is used as the tool for forming the fine hole.

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