JPH02132617A - Groove structure magnetic substrate for perpendicular magnetic recording/reproducing head - Google Patents

Abstract

PURPOSE:To easily and efficiently manufacture a thin film head in a necessary shape by providing plural groove parts, where a non-magnetic material is filled, on one main surface of a magnetic substrate at regular intervals, and using a groove structure substrate obtained with providing V-shaped or U-shaped grooves orthogonal to the groove part at regular intervals. CONSTITUTION:For one main surface of the magnetic material, a groove structure magnetic substrate 1, which is obtained by providing plural flat-bottomed or phased grooves 2 and V-shaped or U-shaped groove parts 20 orthogonal to the grooves 2 for filling an nonmagnetic material 3 at regular intervals, is used. In such a constitution, the shape of the part where the groove part 2 crosses the groove part 20 on the groove structure magnetic substrate 1 can be arranged so that the width of a return path magnetic member parallel part 13 may be approximately the same as that of a main magnetic pole film 7, and the magnetic material of the part other than the magnetic member parallel part 13 may be nonparallel to the main magnetic pole film 7. Thus, the thin film head in the necessary shape can be efficiently manufactured.

Description

[Detailed Description of the Invention] Field of Application The present invention relates to improvements in groove-structured magnetic substrates for perpendicular magnetic recording/reproducing thin film heads for computers, tapes, video recording, etc. The shape of the bottom surface of the groove filled with non-magnetic material, which will face the magnetic recording medium after processing and assembly, is such that the width of the return path magnetic member arranged parallel to the main pole film is approximately equal to the width of the main pole film, and By making the return path magnetic material other than the parallel part of the magnetic member non-parallel to the main pole film, it is possible to easily create a perpendicular magnetic recording/reproducing thin film head that improves the crosstalk characteristics and off-track characteristics of the thin film head. The present invention also relates to a groove structure magnetic substrate that can be manufactured efficiently.

BACKGROUND ART In general, perpendicular magnetic recording/reproducing thin film heads (hereinafter referred to as thin film magnetic heads) are capable of high density magnetic recording in that their magnetic circuits are minute and they use magnetic thin films with high magnetic permeability and high saturation magnetic flux density. Because it is suitable for large-scale applications and is manufactured using a manufacturing process based on semiconductor technology, it is possible to manufacture high-precision magnetic heads at low cost, and it is thought that it will become the mainstream of perpendicular magnetic heads in the future.

Thin film magnetic heads include inductive heads used as recording and reproducing heads, magnetoresistive heads used as reproducing heads, and the like.

For example, an inductive head for perpendicular magnetic recording/reproduction is made of a magnetic member (10) such as soft ferrite, and a magnetic member (10) such as soft ferrite, as shown in FIG. A main magnetic pole film (7) made of permalloy, sendust, Co-based amorphous, etc., disposed through a nonmagnetic material (3) serving as a gap layer, a thin film conductor coil (4), and an insulating layer (5), and the main magnetic pole. It consists of a thick magnetic film (8) and a protective film (9) to prevent magnetic saturation during recording of the film.

Problems with the Prior Art In the vertical thin-film head configured to face the recording medium with the exposed stacked end face described above, as shown in FIG.
) is parallel to the main magnetic pole film (7), so that the boundary surface other than the lower part of the main magnetic pole film (7) Due to the reproduction of adjacent tracks in (12), crosstalk characteristics and off-track characteristics were insufficient in the thin film head, and there was a problem with increasing track density.

Furthermore, in the conventional thin film magnetic head, an edge-shaped portion of the return path magnetic member is exposed in addition to the main pole film on the surface facing the recording medium, and due to the exposed portion shape effect (contour effect), the edge portion Due to the concentration of leakage magnetic flux from the medium, noise peaks occur in the reproduced waveform, that is, sub-peaks (peaks due to the contour effect) occur in addition to the main peak, leading to waveform distortion and deterioration of recording density characteristics. there were.

Purpose of the Invention In view of the current situation, the present invention provides a thin film head that improves the crosstalk characteristics and off-track characteristics of conventional thin film magnetic heads, and a perpendicular magnetic recording/reproducing thin film head that can simultaneously reduce and eliminate problems caused by contour effects. The purpose of the present invention is to provide a magnetic substrate with a groove structure that can be manufactured easily and efficiently.

SUMMARY OF THE INVENTION The inventor reduces the reproduction output of adjacent tracks at the contact portion between a magnetic member for an opposing sliding turn pass in a magnetic recording medium and a non-magnetic material filled in a groove, and improves crosstalk characteristics and off-track characteristics. As a result of various studies on the shape of the return path magnetic member for the purpose of improvement, we decided to change the shape of the bottom surface of the return path groove magnetic member exposed on the surface facing the magnetic recording medium to a return path arranged parallel to the main pole film. The magnetic member width for use is approximately equal to the main magnetic pole film width, and the return path magnetic material other than the self-magnetic member parallel part is non-parallel to the main magnetic pole film, that is, the magnetic material other than the magnetic part former parallel part (10 ) The magnetic member has an inclined surface whose thickness is gradually decreased or increased from the parallel portion of the magnetic member to increase the magnetic resistance and increase the azimuth cross due to the inclined surface of the magnetic member,
It has been found that the crosstalk characteristics and off-track characteristics of the thin film head can be improved.

At the same time, it has been discovered that in order to prevent waveform deterioration due to magnetic flux concentration at alternating corners with the non-magnetic material, the required inner surface of the groove provided in the magnetic member can be made into a specific step-like shape. did.

Therefore, as a result of various studies on materials for easily and efficiently manufacturing a thin film head in which the magnetic member has a specific shape, we found that a plurality of grooves filled with a non-magnetic material were formed on one main surface of the magnetic substrate in a uniform manner. It has been found that the manufacturability can be significantly improved by using a groove structure magnetic substrate in which V- or U-shaped grooves are provided at regular intervals and are provided at regular intervals and are perpendicular to the grooves.

That is, the present invention provides a magnetic substrate with a groove structure for a perpendicular magnetic recording/reproducing thin film head, in which a plurality of grooves filled with a non-magnetic material are provided at regular intervals on one main surface of the magnetic substrate. The inner surface of the groove, which becomes the exposed magnetic member for the return path, is formed to have a flat bottom or a stepped shape, and after assembling the thin film head, the parallel width of the magnetic member of the groove for the return path exposed to the medium facing surface is approximately equal to the width of the main pole film. ,
The return path magnetic material other than the magnetic member parallel portion is
A groove structure magnetic substrate for a perpendicular magnetic recording/reproducing thin film head, characterized in that the groove structure is arranged non-parallel to the main pole film.

Structure of the Invention This invention, as shown in FIGS.
A plurality of flat-bottomed or step-shaped grooves (2) filled with a non-magnetic material (3) such as glass, Si02, A1203, barium titanate, etc. on one main surface of a magnetic material such as Mn-Zn ferrite, and the like. It is characterized by a groove structure magnetic substrate (1) in which orthogonal V-shaped or approximately U-shaped grooves (20) are provided at regular intervals, and by using this, a thin film head of a desired shape can be manufactured easily and efficiently. .

Specifically, by using the groove structure magnetic substrate (1) shown in FIG.
As shown in FIGS. 2a and 2b, the width of the return path magnetic member parallel portion (13) is approximately equal to the main magnetic pole film (7) width, and the width of the magnetic member parallel portion ( 13
) is arranged so as to be non-parallel to the main pole film (7), so here the thickness of the magnetic material (10) other than the magnetic part parallel part (13) is It is possible to efficiently manufacture a thin film head in which the magnetic member is temporarily reduced in size from the upper part (13). Further, the thin film head can increase magnetic resistance and increase azimuth cross due to the inclined surface of the magnetic member, and can improve crosstalk characteristics and off-track characteristics of the thin film head.

Furthermore, by using the groove structure magnetic substrate (1) shown in FIG. 1b, a groove portion (2) corresponding to the surface facing the magnetic recording medium of the thin film head cut out from the substrate and processed as shown in FIG. 2b can be formed. A thin film head is obtained in which the thickness of the magnetic material (10) on the bottom surface is gradually reduced from that of the magnetic member parallel portion (13), and the crosstalk characteristics and off-track characteristics of the thin film head are improved.
improves.

Furthermore, by forming the groove portion (2) on the stepped inner surface (2a), the thin film magnetic head made from the substrate has the following characteristics:
The leakage magnetic flux from the recording medium is caused by at least one alternating corner between the exposed surface of the magnetic part (10) exposed to the medium facing surface and the non-magnetic material (3) filled in the groove part (2), and Since it is dispersed at the contact surface with the non-magnetic material (3), it is possible to weaken the sub-peak due to the contour effect, which was a drawback of conventional thin-film magnetic heads.

The process of manufacturing a thin film magnetic head using the groove structure magnetic substrate according to the present invention will be explained with reference to FIG. 1b and FIGS. 4a to 4g.

■The whole surface of the magnetic substrate (1) made of Ni-Zn or Mn-Zn ferrite has a plurality of grooves (2) having a stepped inner surface (2a) and a substantially U-shaped shape orthogonal to the grooves (2). A plurality of grooves (20) are arranged in a required pattern, and each groove (2x20) is filled with glass, Si02, AI203,
A non-magnetic material (3) such as barium titanate is filled, and then mechanochemical polishing is performed on the main surface of the magnetic substrate (1) on which the grooves (2×20) are provided. (Fig. 1 b) ■ C
A thin film conductor coil (4) made of U, Cr, AI, etc. is formed. (Figure 4a) Note that the magnetic member is Mn-
In the case of Zn-based ferrite, an insulating layer is provided before forming the thin film conductor coil.

■For electrical insulation between this thin film conductor coil (4) layer and the main pole film (7) that will be deposited later, Si02, AI203
An interlayer insulating film (5) made of an inorganic oxide film such as the following is formed by a sputtering method or the like.

(Fig. 4b) ■Interlayer insulation coating (5) formed by the thin film conductor coil (4)
In order to remove the uneven surface, precision polishing such as diamond polishing is performed to flatten the surface to 500A or less. (Figure 4C) ■The main pole film (7) and the magnetic member (10) to be deposited in the post-process.
) is formed in the interlayer insulating film (5) by a method such as ion etching or chemical etching. (Fig. 4 d) ■ Processing strain on the surface of the interlayer insulating film (5) and edge portion (5)
In order to remove the corners of a) and further remove the processing strain on the surface of the magnetic member (10), mechanochemical polishing is applied to the entire main surface.

As a result, the interlayer insulating coating (5) surface and the magnetic member (10) surface of the return path section (6) are free from processing strain and have a surface roughness of 100 or less, preferably 40A or less. Finished in.

■After the mechanochemical polishing, on the surface of the interlayer insulating film (5) and the surface of the magnetic member (10) of the return path section (6),
A main pole film (7) made of Fe-based alloy such as permalloy or sendust or amorphous is sputtered,
It is deposited and patterned using a vapor deposition method, a plating method, etc.

(Fig. 4e) ■After that, a thick main pole film (8) is deposited on the main pole film (7) by sputtering, vapor deposition, plating, etc. in order to prevent magnetic saturation of the main pole. and create a pattern. (
Figure 4 @) ① Layer and deposit the head protective film (9). (Fig. 4 g)
[Stocks] After that, the required position of the groove (2) and the groove (20)
By cutting at the required position and forming into the required size and shape, the groove (2) of the magnetic member has a step-like inner surface (2a), and the portion where the groove (2) and the groove (20) intersect. The width of the return path magnetic member parallel part (13) is approximately equal to the main magnetic pole film (7) width, and the thickness of the magnetic member (1) other than the magnetic member parallel part (13) is the same as the magnetic member parallel part (13). A thin-film magnetic head with a smaller surface area than the (13) plane can be obtained. (Fig. 3) The groove shape of the groove structure magnetic substrate (1) according to the present invention, that is, the shape of the return path magnetic member on the end face of the lamination facing the recording medium, has the shape as shown in Figs. 2 and 3. Alternatively, the shape shown in FIG. 5 may be used.

For example, a stepped groove (2) and a substantially U perpendicular to this
Groove structure magnetic substrate with mold grooves (20) provided at regular intervals (
1), the width of the return path magnetic member parallel part (13) is almost equal to the main magnetic pole film (7) width as shown in FIG. After the thickness of the magnetic material (10) decreases more rapidly than that of the magnetic member parallel portion (13), a shape in which the thickness decreases gradually is obtained.

In addition, by using a groove structure magnetic substrate (1) in which stepped grooves (2) and V-shaped grooves (20) orthogonal thereto are provided at regular intervals, magnetic members for return paths can be parallel to each other as shown in FIG. The width of the portion (13) is approximately equal to the width of the main pole film (7);
A shape is obtained in which the thickness of the magnetic material (10) on the bottom surface of the groove (2) other than the magnetic member parallel portion (13) is gradually reduced from that of the magnetic member parallel portion (13).

In this invention, the step-like inner surface (2a) provided in the groove (2) disposed in the magnetic part +J' (10) has a flat bottom surface as shown in FIGS. 6a and b. It can be formed in the shape of one step or several steps, or it can be formed in any other step-like shape, such as a structure in which the rising part of the step-like inner surface (2a) is inclined as shown in FIG. 6C. The effects described above can be obtained.

Example Examples of the present invention will be described below.

On a Ni-Zn ferrite substrate with a precision-finished surface,
A plurality of grooves each having a width of 0.3 mm, a depth of 0.015 mm, and a length of 50 mm are formed by machining.

Furthermore, a groove with a width of 0.15 mm, a depth of 0.030 mm, and a length of 50 mm is formed in the longitudinal direction near the center of the groove portion by machining.

In addition, a width of 0.015 x a depth of 0 perpendicular to the stepped groove is provided.
．． 05 x length 50 A plurality of hook grooves are formed by machining.

After filling the stepped grooves thus obtained with glass in a state where the number of bubbles of 5 pm or more is 1 bubble/mm3 or less, the main surface is subjected to mechanochemical polishing, and on the polished surface,
A Cu film for a thin film conductor coil is formed by sputtering,
Pattern it into a predetermined shape.

After that, Si was used as an interlayer insulation coating for electrical insulation.
After depositing 02 by sputtering, the surface was subjected to diamond polishing under the following conditions to flatten the surface to 500 mm or less.

Next, after a return path portion was formed in the interlayer insulating film by ion etching, the entire main surface was subjected to mechanochemical polishing under the following conditions.

As a result, the interlayer insulation coating and the exposed magnetic member surface are
The surface roughness was 30A or less.

After mechanochemical polishing, a main magnetic pole film made of Co-based amorphous is deposited and patterned using a sputtering method.
Furthermore, a thick main pole film made of Co-based amorphous was deposited and patterned using a sputtering method.
A head protective film made of 203 was laminated and deposited.

Thereafter, one main surface of the return path magnetic member facing the recording medium is formed in a stepwise manner so that the upper width of the magnetic member on the stacked end face facing the recording medium is equal to the main magnetic film width, and the lower width of the magnetic member is equal to the main magnetic film width. A vertical thin film head was fabricated by cutting into the required size and shape so that it had a ladder shape that was larger than the width of the upper part.

In this manner, the characteristics of the obtained vertical thin film head were evaluated.

For comparison, a vertical thin film head was made using the same method as above using a Ni--Zn ferrite substrate in which a groove of width 0.3 mm and depth of 0.030 mm was filled with glass, and this head was evaluated in the same manner.

FIG. 7 shows test results of off-track characteristics from these two types of heads with different groove shapes.

The off-track characteristics were measured by self-recording and reproducing, and the measurement conditions were as follows.

As is clear from FIG. 7, the head of the present invention exhibits very good off-track characteristics.

Furthermore, in the results of the reproduced output waveforms from two types of heads with different groove shapes, sub-peaks due to the contour effect appeared in the conventional thin-film magnetic head with a flat-bottomed groove structure shown in FIG. In the thin film magnetic head according to the present invention having the stepped groove shown in FIG. 1, the appearance of sub-peaks due to the contour effect was significantly reduced.

Young CoCr/NiFe double layer film, perpendicular coercive force Hc=
10000e Head Both the present invention and the conventional track width TW = 50 pm, 43 mm plate rotation, 3600 rpm Recording density IKFRPI Mechanochemical polishing conditions processing machine; 15 inch MCP polisher; Non-woven powder; Particle size 0.02 pm or less, MgO rotation speed; 2Orpm Pressure force; 0.5kg/mm2 Diamond polishing conditions Processing machine; 15-inch single-sided lapping plate polisher; Sn plate diamond; Particle size 0.5~lpm Rotation speed; 30rpm Pressure force; 0.5kg/mm2 Reproduction output waveform measurement = conditions Disk rotation speed: 3600 rpm Media: Co-Cr/Ni-Fe Recording frequency: IMHz Recording current: 20 mAp-P Relative speed: v=15 m/S

[Brief explanation of the drawing]

FIGS. 1a and 1b are perspective explanatory views of a magnetic substrate according to the present invention. 2a and 2b, 3a and 3b, and 5a and 5b are explanatory front and longitudinal side views of the thin film magnetic head according to the present invention. FIGS. 4a to 4g are explanatory diagrams showing the manufacturing process of the thin film magnetic head according to the present invention. FIGS. 6a to 6c are explanatory diagrams showing the groove shape of the magnetic member. FIG. 7 is a graph showing the relationship between the offset amount and reproduction output of the thin film magnetic head. FIGS. 8a and 8b are longitudinal cross-sectional views of a thin film magnetic head using a conventional magnetic member. DESCRIPTION OF SYMBOLS 1... Groove structure magnetic substrate, 2, 20... Groove part, 2a.
... Stepped inner surface, 3... Nonmagnetic material, 4... Thin film conductor coil, 5... Interlayer insulation coating, 6... Return path portion, 7... Main pole film, 8... Thick film main pole film, 9...
・Head protective film, 10... Magnetic member, 11... Exposed surface, 12... Boundary surface, 13... Parallel part of magnetic member, 3
0...Recording medium.

Claims (1)

[Scope of Claims] 1. In a magnetic substrate with a groove structure for a perpendicular magnetic recording/reproducing thin film head, in which a plurality of flat bottom grooves filled with a non-magnetic material are provided at regular intervals on one main surface of the magnetic substrate, the medium facing surface after the thin film head is assembled. The width of the magnetic member for a return path arranged parallel to the main magnetic pole film is approximately equal to the width of the main magnetic pole film, and the magnetic material for a return path other than the parallel portion of the magnetic member is non-parallel to the main magnetic pole film. . A groove-structured magnetic substrate for a perpendicular magnetic recording/reproducing thin film head, characterized in that grooves perpendicular to the flat-bottomed groove are provided at regular intervals. 2. In a magnetic substrate with a groove structure for a perpendicular magnetic recording/reproducing thin film head in which a plurality of grooves filled with a non-magnetic material are provided at regular intervals on one main surface of the magnetic substrate, after the thin film head is assembled, a magnetic member for a return path on the medium facing surface is removed. The inner surface of the groove portion is formed in a step-like shape, and after the thin film head is assembled, the width of the return path magnetic member arranged parallel to the main pole film on the medium facing surface is approximately equal to the width of the main pole film, and the width of the magnetic member other than the parallel part of the magnetic member is approximately equal to the width of the main pole film. A groove-structured magnetic substrate for a perpendicular magnetic recording/reproducing thin film head, characterized in that grooves are provided at regular intervals perpendicular to the stepped grooves so that the return path magnetic material is non-parallel to the main pole film. .