JPH0883416A - Production of core slider for fixed magnetic disk device - Google Patents

Abstract

PURPOSE: To increase the recording density of a magnetic disk by forming the lateral sections of at least one side parts in the transverse direction of air bearing parts of glass materials at a prescribed width. CONSTITUTION: At least the front surfaces which are the surfaces on the side to face magnetic disks of the air bearing parts 26 are subjected to an etching operation to expose embedded materials 14 consisting of glass together with the constituting material of a slider body 20. Such surfaces are subjected to chemical etching by using an etching liquid consisting of an aq. soln. contg. a citric acid and/or L-ascorbic acid and having high selectivity so that only the embedded glass materials 14 are etched. As a result, the etching of the embedded glass materials 14 existing in both side parts is more accelerated than in the central parts in the transverse direction of the air bearing parts 26 consisting of the material constituting the slider body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a core slider for a fixed magnetic disk device, and more particularly, to a structure in which a magnetic head core forming a recording / reproducing section is integrally assembled to a slider body having an air bearing section. Of the so-called composite type core slider.

[0002]

BACKGROUND ART Conventionally, a fixed magnetic disk device (RD
As a core slider for a floating magnetic head used in D), a slider body provided with a pair of air bearing portions of a predetermined width parallel to each other on a surface of a magnetic disk sliding contact side, and the air bearing portion of the slider body. There is known a structure having a magnetic head core, which is arranged at one end side portion in the extending direction and is formed so that a magnetic gap across a closed magnetic circuit faces a magnetic disk. For example, a slider body having an air bearing portion and a magnetic head core (core chip) forming a recording / reproducing portion are integrally assembled, a so-called composite type or a bulk type A structure using a core, in which a slider body and a magnetic head core are integrally structured, a so-called monolithic type, and The end face of the trailing side of the air bearing portion in the rider body, the structure obtained by forming a thin-film magnetic head core, there are such as those referred to form a so-called thin film type.

In response to the recent demand for high-density recording, various measures have been taken even in such a core slider for a fixed magnetic disk device. For example, with respect to the core, an improvement to reduce its inductance is made. In addition, as a slider, improvements regarding the flying characteristics of the slider, specifically, improvements such as devising the shape of the air bearing portion have been proposed. That is, in the flying-type magnetic head core slider used in the fixed magnetic disk device, the flying height is larger on the outer peripheral side than on the inner peripheral side of the magnetic disk, and the writing and reading capabilities of the magnetic head core are increased. Therefore, in order to keep the flying height at the inner and outer peripheral portions of the magnetic disk constant, U.S. Pat. No. 4,673,996 discloses that both sides in the width direction of the air bearing portion are opposed to the magnetic disk at the central portion. A stepped structure with a flat surface lower than the surface is proposed.

However, accurately forming a stepped portion with a fine depth in the air bearing portion of such a slider body has an inherently difficult problem in manufacturing the core slider. is there. For example, in the case of a composite type core slider, generally, after the core chip is integrally assembled to the slider body, polishing processing is performed to define the depth length of the magnetic gap for each slider. Therefore, it is extremely difficult to form a fine stepped portion on the surface of the air bearing portion facing the magnetic disk, which has been subjected to such polishing, by machining, etching, or the like. It is considered to be a structure that cannot be adopted in. Also,
Even if such fine stepped portions can be formed by an etching operation, a suitable acidic aqueous solution is generally used as the etching solution, which results in significant surface roughness on the etched surface of the air bearing portion. It is extremely difficult to raise the step height accuracy because of the occurrence of this or the high etching rate, and it is not acceptable in practical use.

[0005]

The present invention has been made in view of such circumstances, and the problem to be solved is that it does not cause the problem of surface roughness of the etching surface and that the step height is high. Is to provide a method for industrially advantageously manufacturing a core slider for a fixed magnetic disk device having an air bearing portion with a highly accurate stepped structure, and
It is an object of the present invention to provide a practical manufacturing method capable of manufacturing a core slider having such a useful air bearing portion shape with good productivity and advantageously.

[0006]

In order to solve such a problem, a feature of the present invention resides in that at least a pair of air bearing portions having a predetermined width, which are parallel to each other, are provided on a surface of a magnetic disk sliding contact side. A slider body whose air bearing portion is made of a non-magnetic ceramic material, and a magnetic gap which is disposed at one end side portion of the slider body in the direction in which the air bearing portion extends and which crosses the closed magnetic circuit is magnetic. A method of manufacturing a core slider for a fixed magnetic disk device, comprising: a magnetic head core formed so as to face a disk;
A step of preparing a slider body in which at least one side portion in the width direction of the air bearing portion is formed of a glass material in a predetermined width; and (B) with respect to the air bearing portion of the slider body. , Citric acid and / or L
-Using an etching solution composed of an aqueous solution containing ascorbic acid, an etching operation is performed to etch only the material of at least one side portion of the air bearing portion, so that at least one side of the center portion in the width direction is etched. And a step of forming an air bearing portion having a stepped structure in which the height of the side portion is reduced.

Further, the present invention is advantageously adopted particularly in the production of a composite type core slider, and in that case, specifically, (a) at least one slider body can be provided. A step of preparing a non-magnetic ceramic plate having a size, and (b) at least one of embedded grooves having a predetermined depth is formed in each air bearing portion forming portion of the surface of the non-magnetic ceramic plate on the sliding side of the magnetic disk. A step of forming a glass, and further burying glass in the burying groove; and (c) a pair of air bearing portions that are parallel to each other can be formed from the glass-embedded nonmagnetic ceramic plate. A step of cutting out at least one, and (d) at one end of the cut out slider body, a surface of the slider body on the side of sliding contact with the magnetic disk A core insertion slit extending straight in a predetermined direction in the sliding direction of the magnetic disk is provided, and a coil winding groove is formed on one end of the slider body so as to cross the core insertion slit. And the process of
(E) A pair of air bearings having a predetermined width that are parallel to each other such that the embedded groove portion of the glass remains on at least one side portion in the width direction on the surface of the slider body on the side of sliding contact with the magnetic disk. And (f) prior to or after the step of forming the air bearing portion, the magnetic head core, which is separately manufactured, crosses the closed magnetic circuit so that the magnetic gap faces the magnetic disk. As described above, the step of inserting into the slit for core insertion and integrally assembling, and (g) etching the air bearing portion of the slider body with an aqueous solution containing citric acid and / or L-ascorbic acid. A liquid is used to perform an etching operation so that only the embedded glass portion forming at least one side portion of the air bearing portion is etched. And a step of forming an air bearing portion having a stepped structure in which the height of at least one side portion is lower than that of the widthwise central portion. Become.

In the method of manufacturing a core slider for a fixed magnetic disk device according to the present invention, when the etching solution is an aqueous solution containing citric acid, the aqueous solution is preferably adjusted to pH 2-5. And a buffer is further added. And, as such a buffer, sodium acetate or ammonia is advantageously used. Further, when the etching solution is an aqueous solution containing L-ascorbic acid, the pH is preferably adjusted to 3 to 5.

Further, as the non-magnetic ceramics used in the present invention, ceramics containing calcium titanate (CaTiO ₃ ) as a main component is advantageous. In particular, in the composite type core slider, since ferrite is used as the magnetic material forming the core chip for the magnetic head, such ferrite and ceramics containing CaTiO ₃ as the main component are This is because the coefficients of thermal expansion match well.

Furthermore, it is advantageous that the glass used as the material for forming the side portion of the air bearing portion in the present invention is a glass having a softening point of 520 ° C. or higher. This is in order to avoid deformation of the side portion of the air bearing portion in consideration of the heat history in the subsequent process when manufacturing the core slider.

[0011]

Therefore, in the method of manufacturing the core slider for the fixed magnetic disk device according to the present invention,
The center portion of the air bearing portion in the width direction is a flat surface that is closest to the magnetic disk over a predetermined length, while at least one side portion in the width direction of the air bearing portion has A two-step structure (step) composed of a material (glass) having an etching characteristic different from that of the bearing portion constituent material (non-magnetic ceramics) and configured as a plane one step lower than the closest plane to the magnetic disk. That is, the air bearing part of the attached structure is formed.

Further, the air bearing portion in which such a two-stepped structure is exposed has different etching characteristics.
It is not necessary to form an accurate mask corresponding to the air bearing portion on the surface of the magnetic disk sliding contact side based on the fact that it is composed of a predetermined kind of material, and citric acid and / or L -The surface of the material forming at least one side portion in the width direction of the air bearing portion can be selectively etched by only a simple etching operation using an etching solution composed of an aqueous solution containing ascorbic acid. In other words, the etching operation can be performed on the surface of the air bearing portion of the composite structure by utilizing the etching selection ratio of the composite materials, and thus the air bearing portion of the two-step structure is provided. Can be advantageously formed with good productivity.

In particular, the surface of at least one side portion in the width direction of the air bearing portion is selectively etched by this selective etching operation, so that the precision of the air bearing portion relative to the center portion in the width direction is improved. Since it is no longer necessary to carry out such a mask, even in the composite type core slider, it is possible to advantageously form a two-step structure for the air bearing portion of the composite type core slider. As an aqueous solution containing citric acid and / or L-ascorbic acid, the surface roughness of the etching surface of the air bearing portion having such a two-stage structure is effectively suppressed, and a problem based on that is generated. While avoiding
By improving the etching accuracy to improve the accuracy of the step height, further improving the safety of the etching work, and reducing the etching cost, it was possible to significantly improve the industrial property.

Since it is possible to manufacture a core slider for a fixed magnetic disk device having such a two-stage air bearing portion, there is also a problem that the flying height of the core slider on the outer peripheral side of the magnetic disk increases. ,
Therefore, it can be effectively solved, and thus it is possible to advantageously deal with the increase in recording density of the magnetic disk.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be more specifically clarified below based on a typical example of a method of manufacturing a core slider for a fixed magnetic disk device shown in the drawings.

First, FIG. 1 to FIG. 9 show members used in an example of a method of manufacturing a core slider for a fixed magnetic disk device according to the present invention, a working mode and an assembling mode thereof, and a product mode. There is. In manufacturing a composite type core slider having a two-stage air bearing portion as shown in FIG. 9, at least one slider body having a size capable of providing at least one slider body as shown in FIG. The plate-shaped slider material 10 is prepared.

Now, the slider material 10 to be prepared is prepared.
Is set to be slightly larger than the intended length of the core slider in the sliding direction of the magnetic disk. Further, the thickness of the slider material 10 is set to be thicker than the intended thickness of the core slider. Further, the length of the slider material 10 in the direction orthogonal to the sliding direction of the magnetic disk is set so that a plurality of target core sliders (slider bodies), here, three slider bodies can be obtained. At least a non-magnetic ceramic material is used as a material forming the slider material 10. Among them, a magnetic head core (so-called core chip) whose thermal expansion coefficient is described later is used.
The ferrite that forms the element that is as close to that as possible will be adopted, but especially calcium titanate (C
aTiO ₃ ), or a ceramic material containing CaTiO ₃ as a main component, to which a small amount of additives is added, is preferably used. This non-magnetic ceramic material constitutes at least each air bearing portion forming portion of the slider material 10.

As shown in FIG. 2, the surface of the slider material 10 on the sliding contact side of the magnetic disk is embedded with a groove 12 of a predetermined width with respect to each air bearing portion forming portion.
Are formed in parallel with each other at a predetermined depth. The embedding grooves 12 are located on both sides of the finally formed air bearing portion, and have a space narrower than the width of the air bearing portion so that the side portion has a predetermined width. Formed in sets, here six sets of ten embedding grooves 12 (two of which are common embedding grooves) are formed for taking three sliders, and the embedding grooves of one set are formed. The intervals of 12 and 12 are processed so as to be the width of the air bearing surface closest to the magnetic disk. In addition, the depth of the buried groove 12 is, when it is polished by the final gap depth processing, as will be described later, when the material having different etching characteristics, such as glass, which is buried in the buried groove 12, is formed later. Even if the etching process is performed, it is set to remain.

Next, as shown in FIG. 3, the slider material 10 in which a plurality of embedding grooves 12 are formed by performing such groove processing, as shown in FIG. A material (glass) 14 having an etching characteristic different from that of the material (nonmagnetic ceramics) forming 10 (the air bearing portion) is embedded. That is,
This embedding material 14 is selected in consideration of the constituent material of the slider material 10, and generally, a material which is not etched at all under a predetermined etching condition is used as the constituent material of the slider material 10 or a material which is etched. In addition to being selected as the embedding material 14, it is also possible to select materials having different etching rates (speeds) as both of them, but in the present invention, a nonmagnetic ceramic material is used as the constituent material of the slider material 10. On the other hand, as the embedding material 14, glass is used.

The glass used as the embedding material 14 preferably has a softening temperature of at least 520.degree. This is because when the core is fixed to the slider in a later step, it is preferable to be higher than the working temperature of the fixing glass in order to avoid the deformation of the glass of the embedding material 14, and normally the working temperature for fixing the core is 450 to 520. ℃
Therefore, it is desirable to select a glass having a softening temperature above this working temperature. Therefore, as a glass effective as an embedding material, for example, a softening temperature: 650
℃ BaO-La ₂ O ₃ with a glass -SiO ₂ system,
After setting the plate-shaped glass (14) on the embedding groove 12, it is heated to a working temperature of 900 ° C. and poured,
The embedded groove 12 is filled. After embedding the glass (14) in this way, excess glass that has run off is removed and polished, and both end faces in the forming direction of the embedding groove 12 in the slider material 10 corresponding to the end faces in the slider longitudinal direction are also polished. The glass (14) is made to be embedded in the embedding groove 12 without excess or deficiency.

In addition to the processing method described above, up to the step of burying the glass (14), a plurality of plate-shaped slider materials 10 shown in FIG. 1 and a large material to be sampled are prepared in advance. On the other hand, a method for obtaining the slider material 10 as shown in FIG. 3 by dividing it into a plurality of pieces after performing grooving processing similar to FIG. 2 and further embedding glass or the like. Can also be adopted appropriately,
Needless to say.

As shown in FIG. 4, the slider material 10 in which the embedding material 14 made of a predetermined glass thus obtained is embedded in the embedding groove 12, as shown in FIG.
In, a plurality of (here, three) slider bodies are cut out in such a size that a pair of air bearing portions that are parallel to each other can be formed by division processing. As a result, it is possible to obtain the slider main body 20 having the same length and width as the target slider and having a slightly thicker thickness. It should be noted that FIG. 5 shows an example of such a cut slider body 20.

Next, as shown in FIG. 6, the slider body 20 has a direction perpendicular to the surface of the slider body 20 on the sliding contact side of the magnetic disk on one end side in the extending direction of the embedding groove 12. And a core insertion slit 22 extending for a predetermined length in the magnetic disk sliding contact direction (direction parallel to the extension direction of the embedding groove 12) is provided, and for the coil winding so as to cross the core insertion slit 22. Groove 24
Is formed on the end surface of the one end of the slider body 20 with an inclination. That is, a core insertion slit 22 for inserting a core chip, which will be described later, is formed between the pair of glass-molded embedding grooves 12 at the trailing end of the slider body 20 and is larger than the thickness of the core chip. On the other hand, a coil winding groove 24 for forming a coil winding on a core chip, which will be described later, is formed obliquely on the trailing side end surface of the slider body 20.

Further, the surface of the slider body 20 on the sliding contact side of the magnetic disk is subjected to grooving for defining the final width of the air bearing portion with a grindstone. A pair of air bearing portions 26, 26 having a predetermined width and parallel to the surface on the sliding contact side are defined by the air bearing portion defining groove 28. That is, here, a pair of the air bearing portions 26 are formed by leaving the embedding groove 12 portion in which the embedding material 14 such as glass is embedded at a predetermined width on both sides of the air bearing portion 26 in the width direction. 26 is formed.

Thereafter, a magnetic head core, which is separately manufactured, is attached to the slider body 20 thus grooved.
A so-called core chip is integrally assembled. The core chip 30 used here has a structure similar to that of the conventional one, and for example, as shown in FIG. 7, a magnetic material, preferably Mn-Zn, is used. It is made of a ferrite material such as ferrite and forms a rectangular annular structure as a whole that gives a closed magnetic circuit. One end of the annular structure is defined by an inclined surface 32 along one surface in the width direction at its upper side. A narrow width portion 34 serving as a track portion is provided, and a magnetic gap 36 for recording / reproducing is provided in the middle of the narrow width portion 34 so as to cross the closed magnetic circuit. A coil winding hole 38 similar to the conventional one is formed at the center of the core chip 30.

The core chip 30 is attached to the slider body 20.
8 is inserted into the core insertion slit 22 and fixed with a low melting point glass, the inclined surface 32 of the core chip 30 is located at the inner side of the core insertion slit 22 as shown in FIG. The core chip 30 to one side so that the narrow width portion 34 is positioned at the center of the core insertion slit 22 in the width direction, and the gap on the bottom surface side of the slider body 20 in the core insertion slit 22 is positioned. Insert a suitable spacer (preferably a spacer made of non-magnetic material) into the
Then, a low melting point glass (softening temperature: 420 ° C.) (42) is poured around the track portion (34) of the core chip 30 to fix the core chip 30. After that, the spacer intervening in the gap on the bottom surface side of the slider body 20 is removed, and an appropriate fixing resin 4 is placed in such a gap.
4 will be embedded. After that, depth polishing processing is performed to define the gap depth length of the magnetic gap 36 of the core chip 30.
On the leading side of the pair of air bearing portions 26, 26 at 0, a taper portion (leading ramp) 40 having a gentle slope is formed.

Then, the core slider having the core chip 30 integrally assembled to the slider body 20 is subjected to the selective etching operation according to the present invention, so that the pair of air bearing portions 26 in the slider body 20. , Embedded glass (1
4) Only the portion is etched, and as shown in FIG. 9, an air bearing portion 26 having a two-step structure in which the height of both side portions is lower than that of the center portion in the width direction is formed. is there. That is, the etching operation is performed on at least the upper surface of the air bearing portion 26 on the side facing the magnetic disk. The upper surface of such an air bearing portion 26, together with the constituent material of the slider body 20, The embedding material 14 made of glass is exposed, so that for such a surface, only the embedding glass material 14 is etched and citric acid and / or
Alternatively, chemical etching is performed using an etchant (etching liquid) having a large selectivity, which is composed of an aqueous solution containing L-ascorbic acid, whereby the central portion in the width direction of the air bearing portion 26 made of the slider body constituent material. Embedded glass material 1 present on both sides than
The etching for 4 will be further promoted.

That is, in the present invention, in such an etching operation, an etching solution comprising an aqueous solution containing citric acid and / or L-ascorbic acid is used for selective etching of the glass as the embedding material 14. The
As a result, the etched glass surface having a small roughness is advantageously formed. Then, when an aqueous solution containing citric acid is used as the etching solution, the pH of the solution is advantageously set to 2 to 5. Particularly, the pH of the citric acid aqueous solution is 2 to
An aqueous citric acid solution having a concentration of 2.3, that is, 0.1 to 5% by weight, in other words, a concentration of 1 to 5% by weight, is preferably used because of stability of etching rate. Also,
When an aqueous solution containing L-ascorbic acid is used as the etching solution, the pH of the solution is advantageously 3-5. P of these two types of etching solutions
If H is too high, it becomes difficult to perform an effective etching operation on the glass, and if it is too low, it becomes difficult to control the etching amount, or surface roughness occurs. . Above all,
A buffering agent such as sodium acetate or ammonia is particularly advantageously added to the aqueous solution containing citric acid as the etching solution. By adding this buffering agent, the etching rate can be reduced and the change of the etching depth with respect to the concentration (pH) can be blunted, and the precision of the etching depth control can be extremely enhanced. Further, in etching using such an etching solution, the solution temperature is generally 20 ° C. to 50 ° C., preferably 20 ° C. to 30 ° C., which has a low etching rate from the viewpoint of controlling the etching rate. The above-mentioned citric acid and L-ascorbic acid are preferably used not only as an aqueous solution alone but also as a mixed aqueous solution obtained by adding them together.

At this time, the track portion (34) and the track glass around it, that is, the low melting point glass (4
In order to prevent 2) from being etched, their surfaces are appropriately masked with a photoresist or the like, and chemical etching is performed. Further, in order to avoid etching of the side surfaces of the embedded glass (14) located on both sides of the air bearing portion 26 except the upper surface, appropriate masking may be applied to the side surfaces. It should be noted that these masking operations are far easier than the technical and man-hour problems of forming a pattern for etching the air bearing by applying a resist to each slider body, exposing and developing the resist. It is a thing.

Before and after such etching, although not shown, the trailing side of the air bearing portion 26 is subjected to chamfer processing. If this chamfer processing is performed after the etching operation, It is also possible to eliminate the stepped portion of the embedded glass material 14 portion at the longitudinal end of the air bearing portion 26.

By such selective etching operation, the air bearing portion 26 is separated from the magnetic disk, which is lower than the plane 26a closest to the magnetic disk and the plane 26a closest to the magnetic disk, at least on the surface facing the magnetic disk. Although it will be formed by a two-step structure composed of the flat surface 26b, as shown in FIG.
The difference in height between the two planes 26a and 26b: a is about 0.5 to 2 μm so that the lower plane 26b of the etched embedded glass material 14 portion also functions as the air bearing portion 26. It is desirable to do. The length of the embedding groove 12 in which the embedding glass material 14 is left on both sides of the air bearing portion 26 in the width direction of the air bearing portion 26: b is 10 to 200 μm.
And the depth of the embedding groove 12 after the air bearing portion 26 is polished by depth polishing processing: c
Is 20 μm or more. When the depth: c of the embedded groove 12 becomes shallow, the side surface of the embedded glass material 14 is etched by the above-described selective etching operation, so that another stepped portion is formed. The attached portion causes a problem that the floating characteristic of the core slider is changed.

In the above manufacturing method, the air bearing portion 2
As the glass that is the embedding material 14 that constitutes the both sides of 6,
Use a softening temperature of 520 ° C, and use the core chip 30
As the glass 42 for fixing chips, the softening temperature is 420 ° C.
Even if the air bearing portion defining groove 28 is formed before the core chip 30 is fixed by using the above-mentioned one and the working temperature is 500 ° C., when the core chip 30 is fixed later,
The glass (14) constituting the air bearing portion 26 is hardly deformed, and the desired width of the air bearing portion 26 can be secured.

Although the first manufacturing method according to the present invention has been described above, the present invention can also be carried out according to the following procedure. That is, the process is the same as the first manufacturing method described above until the glass molded slider body 20 shown in FIG. 5 is obtained. In addition,
The same glass as the track mold glass (42) is used as the glass (14) that constitutes both sides of the air bearing portion 26. As the next step,
12, the core insertion slit 22 and the coil winding groove 24 are formed, and then, as shown in FIG. 12, the core insertion of the slider body 20 is performed as in the first manufacturing method. The separately manufactured core chip 30 is inserted into the slit 22 for use, and the low melting point glass (softening temperature: 4
(20 ° C.) 42 is melted and the core chip 30 is integrally fixed to the slider body 20. Then, as shown in FIG. 13, the air bearing portion 26
Forming a groove (28) defining Furthermore, gap depth polishing, followed by leading ramp processing,
Then, similarly to the first manufacturing method, the embedded glass material 14 constituting both side portions of the air bearing portion 26 is etched by about 0.5 to 2 μm by a selective etching operation. In the form as shown in 10,
The core slider having the air bearing portion 26 having a two-step structure is obtained.

According to such a manufacturing method, after the slider body 20 and the core chip 30 are fixed by the chip fixing glass 42, the groove for forming the air bearing portion 26 is formed. The subsequent high temperature process is eliminated, and the glass (14) constituting both sides of the air bearing portion 26 is not deformed, so that it is possible to advantageously secure a predetermined size and shape. Further, as compared with the first manufacturing method, the glass constituting both sides of the air bearing portion 26 (1
There is an advantage that the etching of 4) is easily performed and the etching can be performed with greater selectivity.

The method of manufacturing the core slider for a fixed magnetic disk drive according to the present invention has been described above in detail with reference to a typical example thereof, but the present invention is limited to such specific examples. It is understood that the present invention is not to be interpreted and can be carried out in a form in which various changes, modifications and improvements are made based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

For example, although the application of the present invention to the composite type core slider has been described in the specific example of the above example, the present invention may also be applied to a composite type core slider having another structure, such as a side portion of the slider body. It can also be applied to a structure in which the core chip is integrally fixed,
Further, it is similarly applicable to a monolithic type or thin film type core slider.

In the illustrated embodiment, the stepped structure having two steps is realized on both sides of the air bearing portion according to the present invention. However, one side portion of the air bearing portion is provided. In some cases, such a two-stepped structure may be formed, and even in such a structure,
It can be advantageously realized in accordance with the present invention.

Furthermore, as the slider material (10), a composite material of non-magnetic ceramics and other ceramics (for example, ferrite) is used, and the air bearing portion (26) is used.
It is also possible to configure the slider body (20) so that is formed of the non-magnetic ceramic.

[0039]

EXAMPLES The present invention will be described more concretely by showing examples of a method of manufacturing a core slider for a fixed magnetic disk drive according to the present invention.

Example 1 First, an intended core slider for a fixed magnetic disk device was manufactured according to the first manufacturing method according to the present invention shown in FIGS. As the slider material 10,
A non-magnetic ceramic material containing calcium titanate as a main component was used, while the core chip 30 was made of a ferrite material and had a similar structure to the conventional one. Further, as the embedded glass material 14, BaO—La ₂ O—SiO ₂ based glass having a softening temperature of 650 ° C. is used, and this is heated and melted in the embedded groove 12 formed in the slider material 10 to be filled. Let

Then, as shown in FIG. 8, for the core slider in which the core chip 30 is integrally assembled to the slider body 20, other than the embedded glass material 14 portion on the upper surface of the air bearing portion 26, Selective etching is performed at a temperature of 30 ° C. by using a citric acid aqueous solution (pH = about 2) having a concentration of 3% by weight as an etching solution under the condition that the portion is masked with a resist.
As shown in FIGS. 9 and 10, a core slider having an air bearing portion 26 having a two-step structure was obtained. In addition, the embedded glass material 14 was
The etching depth (a) of the portion is 0.75 μm, and the surface roughness of the etched surface is R _max = 0.01 μm.
Became.

On the other hand, when the above-described selective etching operation was carried out using a conventionally known phosphoric acid aqueous solution as an etching solution, the etching depth (a) = 0.
The surface roughness was 3 μm and the etching surface roughness (R _max ) was 0.03 μm. The phosphoric acid concentration in the phosphoric acid aqueous solution was 0.1% by weight (pH = about 2), and the etching temperature was 30 ° C.

As is clear from the comparison between the citric acid aqueous solution and the phosphoric acid aqueous solution as the etching solution in the above selective etching operation, when the citric acid aqueous solution is used, compared with the case where the phosphoric acid aqueous solution is used. It is understood that even if the etching depth is doubled or more, the surface roughness of the etched surface is only 1/3, and a good surface is formed.

Further, as a result of carrying out the selective etching operation similar to the above by changing the citric acid concentration in the citric acid aqueous solution variously, the relationship between the citric acid concentration and the etching depth as shown in FIG. 14 was obtained. Etching temperature: 30
C., etching time: 60 minutes. Then, as is clear from FIG. 14, in the selective etching operation using the citric acid aqueous solution, the lower the concentration of citric acid, the greater the change in the etching depth with respect to the concentration (pH). In order to increase the depth accuracy, it is important to control the concentration of the citric acid aqueous solution.

Example 2 As an etching solution, various citric acid aqueous solutions (citric acid concentration: 3% by weight) prepared by adding 10% by weight sodium acetate aqueous solution at various ratios were used.
In the same manner as described above, the embedded glass material 14 was selectively etched, the relationship between the amount of the sodium acetate aqueous solution as a buffer and the etching depth was investigated, and the results are shown in FIG.
5 shows. The etching temperature was 31 ° C. and the etching time was 30 minutes. Further, FIG. 15 also shows the pH value corresponding to the added amount of the sodium acetate aqueous solution.

As is clear from FIG. 15, the addition of the buffering agent (sodium acetate aqueous solution) reduces the etching rate and can slow down the change of the etching depth with respect to the concentration (pH).
As a result, the precision of etching depth control can be extremely enhanced.

As the etching liquid, citric acid: 3
Etching temperature: 30 using an aqueous solution of pH 4.5 containing 5% by weight and 5% by weight sodium acetate as a buffer.
FIG. 16 shows the result of determining the relationship between the etching depth and the etching time by performing the selective etching similar to the above at ° C. From FIG. 16, it is recognized that the etching time and the etching depth have a proportional relationship.

Example 3 As an etching solution, a 1 wt% concentration L-ascorbic acid aqueous solution (pH = about 5) was used, and the embedded glass material 14 was selectively etched in the same manner as in Example 1. Etching time: 60 minutes, etching temperature: 25 ° C
Thus, an etching depth of 1.8 μm was obtained. The surface condition of the etched surface was a little inferior to the case where the citric acid aqueous solution was used as the etching solution, but it is better (smaller surface roughness) than the etching surface when the phosphoric acid aqueous solution was used. Admitted.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view showing an example of a slider material used in a method of manufacturing a core slider for a fixed magnetic disk device according to the present invention.

FIG. 2 is a perspective explanatory view showing a form in which an embedded groove is formed in the slider material shown in FIG.

FIG. 3 is a perspective explanatory view showing a state in which an embedding material made of a predetermined glass is filled in an embedding groove formed in the slider material in FIG.

FIG. 4 is an explanatory view showing a cutting position for cutting the slider body from the slider material in which the embedding material shown in FIG. 3 is embedded.

5 is a perspective view explanatory diagram showing a slider body obtained by dividing the slider material at the cutout position shown in FIG. 4. FIG.

6 is a perspective explanatory view showing a slider body formed by forming a core insertion slit, a coil winding groove, and an air bearing portion defining groove in the slider body shown in FIG.

7 is a perspective explanatory view showing an example of a separately manufactured core chip that is integrally fixed to the slider body shown in FIG.

8 is a perspective explanatory view showing a state in which the core chip shown in FIG. 7 is assembled and integrally fixed to the slider body shown in FIG.

9 is a view showing a state in which the air bearing portion of the slider body integrally assembled with the core chip shown in FIG. 8 is subjected to a selective etching operation to form an air bearing portion having a stepped structure. FIG.

10 is an enlarged front view of the main part of the air bearing portion viewed from the trailing side of the slider body in FIG.

FIG. 11 is a perspective explanatory view showing a mode in which a core insertion slit and a coil winding groove are formed in the slider body in another example of the method of manufacturing the core slider for the fixed magnetic disk device according to the present invention.

12 is a perspective explanatory view showing a form in which a core chip is integrally attached to the slider body shown in FIG.

13 is a perspective explanatory view showing a form in which an air bearing portion defining groove is formed on the slider body shown in FIG.

FIG. 14 is a graph showing the relationship between citric acid concentration and etching depth obtained in Example 1.

15 is a graph showing the relationship between the amount of sodium acetate added and the etching depth obtained in Example 2. FIG.

FIG. 16 is a graph showing the relationship between the etching time and the etching depth obtained by using an aqueous solution of sodium acetate-added citric acid as an etching solution in Example 2.

[Explanation of symbols]

10 slider material 12 embedding groove 14 embedding material 16 cutout wire 20 slider body 22 core insertion slit 24 coil winding groove 26 air bearing portion 28 air bearing portion defining groove 30 core chip 32 slanted surface 34 narrow portion 36 magnetic gap 38 Coil winding hole 40 Tapered portion 42 Chip fixing glass 44 Adhesive resin

Claims (7)

[Claims] 1. A slider body in which a pair of air bearing portions having a predetermined width are provided parallel to each other on a surface of a magnetic disk sliding contact side, and at least the air bearing portions are formed of a non-magnetic ceramic material. A magnetic head core which is arranged at one end side portion in the direction in which the air bearing portion of the slider body extends and which is formed so that a magnetic gap across the closed magnetic circuit faces the magnetic disk. A method of manufacturing a core slider for a fixed magnetic disk device, comprising the step of preparing a slider body in which at least one side portion in the width direction of the air bearing portion is formed of a glass material in a predetermined width. And an etch of an aqueous solution containing citric acid and / or L-ascorbic acid for the air bearing portion of the slider body. By performing an etching operation using a coating solution to etch only the material of at least one side portion of the air bearing portion, the height of at least one side portion of the air bearing portion can be made higher than that of the central portion in the width direction. And a step of forming an air bearing portion having a lowered stepped structure, the method of manufacturing a core slider for a fixed magnetic disk device. 2. A step of preparing a non-magnetic ceramic plate having a size capable of providing at least one slider body, and a predetermined depth at each air bearing portion forming portion of the surface of the non-magnetic ceramic plate on the sliding contact side of a magnetic disk. Of at least one of the embedded grooves, and further burying glass in the embedded groove, and a pair of air bearing portions parallel to each other can be formed from the non-magnetic ceramic plate in which the glass is embedded. In size, a step of cutting out at least one of the slider bodies, and at one end of the cut out slider body,
A core insertion slit extending in a direction perpendicular to the surface of the slider body on the sliding contact side of the magnetic disk and extending for a predetermined length in the sliding contact direction of the magnetic disk is provided, and a coil winding groove is formed so as to cross the slit for core insertion. A step of forming the end surface of one end of the slider main body, and so that the embedded groove portion of the glass is left on at least one side portion in the width direction on the surface of the slider main body on the sliding side of the magnetic disk. And forming a pair of air bearing portions having a predetermined width that are parallel to each other, and a magnetic head core, which is separately manufactured, prior to or after the air bearing portion forming step, is formed into a closed magnetic circuit. Inserting into the slit for core insertion so that the magnetic gap across the magnetic disk faces the magnetic disk, and assembling integrally, with respect to the air bearing portion of the slider body. Etching is performed by using an etching solution composed of an aqueous solution containing citric acid and / or L-ascorbic acid so that only the embedded glass portion constituting at least one side portion of the air bearing portion is etched. By
A step of forming an air bearing part having a stepped structure in which the height of at least one side part is lower than the widthwise central part. Method. 3. The method of manufacturing a core slider for a fixed magnetic disk device according to claim 1, wherein the etching solution is an aqueous solution containing citric acid and is adjusted to have a pH of 2 to 5. 4. The fixed magnetic disk according to claim 1, wherein the etching solution is an aqueous solution containing citric acid, and a buffering agent is further added to the aqueous solution. Method for manufacturing core slider for device. 5. The method of manufacturing a core slider for a fixed magnetic disk device according to claim 4, wherein the buffer is sodium acetate or ammonia. 6. The method of manufacturing a core slider for a fixed magnetic disk device according to claim 1, wherein the etching solution is an aqueous solution containing L-ascorbic acid and is adjusted to pH 3 to 5. 7. The method of manufacturing a core slider for a fixed magnetic disk device according to claim 1, wherein the glass is a glass having a softening point of 520 ° C. or higher.