JPH07282422A - Production of magneto-resistance effect type magnetic head - Google Patents

Abstract

PURPOSE:To improve and stabilize the characteristics of a magnetic head by previously working a substrate so as to have the warpage of a direction opposite to the direction of the warpage generated by a heat treatment after formation of a lower layer shielding core. CONSTITUTION:The substrate is previously so worked as to have the warpage of the direction opposite to the direction of the warpage generated by the heat treatment for stabilizing the characteristics of 'sendust (R)' constituting the lower layer shielding core. Next, the lower layer shielding core is formed on the film of Al2O3 formed on the substrate. The core is formed by forming the film of the 'sendust (R)', then working the film to a prescribed shape. The core is then subjected to the heat treatment at about 500 to 600 deg.C in order to stabilize the magnetic characteristics of the 'sendust (R)'. Consequently, the substrate which is previously provided with the warpage is warped in the opposite direction and is thereby flattened. The Al2O3 film 2 and the lower layer shielding core 3 are formed on the flattened substrate 1.

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 magnetoresistive effect magnetic head for recording / reproducing information on / from a hard disk, for example.

[0002]

2. Description of the Related Art For example, as a read-only magnetic head constituting a composite type magnetic head mounted in a hard disk drive device or the like, a magnetoresistive effect type magnetic head (hereinafter referred to as MR head Called.)
Is commonly used.

The MR head has a magnetoresistive effect element (hereinafter referred to as M
It is called an R element. ), A bias conductor that gives the MR element a magnetized state in a desired direction, and a pair of magnetic shield cores sandwiching these.

Such an MR head includes an MR element and a bias conductor between a pair of magnetic shield cores which are laminated on a substrate called a slider made of a non-magnetic material such as ceramics so as to face each other with a predetermined gap. And the playback gap is the contact surface with the hard disk, that is, ABS.
It is provided so as to face the (air bearing surface) surface, and a gap film made of a non-magnetic material is arranged between the magnetic shield core and the MR element to magnetically insulate the magnetic shield core and the MR element. Has been done.
And, of course, the gap length of the reproducing gap is determined by the thickness of the gap film.

The MR head as described above is manufactured as follows. That is, first, a thin film made of a magnetic material is formed on a substrate made of ceramics such as alumina titanium carbonate (Al ₂ O ₃ —TiC, so-called Altic material), and processed into a predetermined shape to form a lower shield core. To form.

The lower shield core is used only as a magnetic shield, and sendust is effective as a magnetic material forming the lower shield core in terms of magnetic characteristics. And, when sendust is used as described above, in order to stabilize the magnetic characteristics of sendust, 5
It is necessary to perform heat treatment (annealing treatment) at 00 ° C to 600 ° C.

In order to improve the insulating property and surface property of the substrate, it is general that a thin film made of alumina (Al ₂ O ₃ ) is previously formed on the substrate by sputtering.

Next, in order to flatten the lower shield core, a flattening film made of alumina or the like is formed on the substrate on which the lower shield core is formed, and the surface thereof is mechanically polished by using diamond abrasive grains or the like. The surface is polished by. In addition,
At this time, the thickness of the lower shield core is also defined to be a predetermined thickness.

Then, a lower gap film made of alumina or the like is formed on the lower shield core, and the surface thereof is smoothed by a mechanochemical polishing means or the like.

Subsequently, a metal thin film having a magnetoresistive effect is formed on the lower gap film by a technique such as sputtering, and this is processed into a predetermined shape by a photolithography technique and an etching technique to form an MR element.

Further, an insulating film made of SiO ₂ or the like is formed on the MR element, and a bias conductor which gives the MR element a magnetized state in a desired direction is formed thereon. In forming the bias conductor, thin films are laminated in the order of Ti / Cu / Ti by a method such as sputtering and processed into a predetermined shape by photolithography technique and etching technique to form the bias conductor.

Then, a thin film made of a non-magnetic material such as Ti is formed on the bias conductor by sputtering,
An upper gap film is formed.

Next, a thin film made of a magnetic material such as permalloy is formed on the upper gap film and processed into a predetermined shape to form an upper shield core.

[0014]

However, when the MR head is manufactured as described above, the substrate is likely to be deformed by the heat treatment for stabilizing the magnetic characteristics of the sendust which constitutes the lower magnetic shield core.

When the thin film made of alumina is formed on the substrate, the alumina thin film is also deformed. For example, the above-mentioned alumina thin film warps in a convex shape because the film stress of the alumina thin film and the thermal stress at the time of film formation are released. On the other hand, the fact that the alumina thin film warps in a concave shape is due to the relationship between the alumina thin film and the sendust thin film.

As described above, when the substrate is warped, a flattening film is formed in a subsequent step, and when the surface is flat-polished, the substrate is unevenly contacted with the polishing platen and is formed on the substrate. The amount of polishing of the lower shield core and the flattening film to be performed cannot be made uniform, resulting in uneven wear of the lower shield core or variation in the thickness of the lower shield core. Therefore, the characteristics of the lower shield core deteriorate, and the characteristics of the manufactured MR head also deteriorate. further,
When the substrate is warped as described above, it becomes impossible to make the polishing amount uniform even in the mechanochemical polishing or the like in the subsequent step, and the characteristics of the MR head are impaired.

Further, in manufacturing the MR head as described above, various thin films are formed by a method such as sputtering, or processed into various shapes by photolithography technology and etching technology. However, when the substrate is warped as described above, it causes uneven coating of the resist in the photolithography process and a decrease in patterning accuracy, which impairs the productivity of the MR head. Further, in the sputtering or etching process, the cooling effect of the substrate is reduced, which leads to a reduction in the productivity of the MR head.

Therefore, the present invention has been proposed in view of the conventional circumstances, and it is possible to prevent the deformation of the substrate, perform various polishing processes with good precision, and improve and stabilize the characteristics of the magnetic head. Of a magnetoresistive effect magnetic head capable of improving productivity of a magnetic head by preventing uneven coating of a resist in the photolithography step and a decrease in patterning accuracy, a decrease in a cooling effect of a substrate in a sputtering or etching step. It is intended to provide a manufacturing method.

[0019]

In order to achieve the above-mentioned object, the present invention is to form a lower layer shield core made of sendust on a substrate made of ceramics, heat-treat the substrate, and place the lower layer shield core on the substrate. In the method of manufacturing a magnetoresistive effect magnetic head, wherein a magnetoresistive effect element is provided via an insulating layer, and an upper shield core made of a magnetic material is formed on the magnetoresistive effect element via an insulating layer. It is characterized in that it is processed in advance so as to have a warp in a direction opposite to the direction of the warp caused by the heat treatment after the formation of the lower shield core.

In the method of manufacturing the magnetoresistive effect magnetic head as described above, a thin film of alumina may be formed on the substrate, and the ceramic may be alumina titanium carbonate.

[0021]

The present invention provides a method of manufacturing a magnetoresistive effect magnetic head in which a lower layer shield core made of sendust is formed on a substrate made of ceramics, and then the substrate is heat-treated. It is processed so as to previously have a warp in a direction opposite to the direction of the warp caused by the heat treatment. That is, in the above heat treatment, the substrate warps in the direction opposite to the processed direction, and the substrate is flattened. Therefore, the lower shield core formed on the substrate does not warp.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. In this example,
The present invention is applied to a manufacturing method for manufacturing a composite magnetic head in which a so-called inductive head, which is a recording head, is stacked on an MR head.

To manufacture the composite type magnetic head, first,
Alumina Titanium Carbonate (Al ₂O₃-TiC, yes
A base called a slider made of altic material)
A film is formed on the plate for the purpose of improving the insulation and surface properties of the substrate.
Alumina film with a thickness of 10 μm (hereinafter referred to as Al₂O₃Called a membrane
It ) Is formed by sputtering.

In the present embodiment, the substrate has a warp in the direction opposite to the direction of the warp generated in the substrate by the heat treatment for stabilizing the characteristics of the sendust which constitutes the lower shield core, which will be described later. To process. That is, a substrate which is convexly curved by heat treatment is processed into a concave shape in advance, and a substrate which is curved concavely by heat treatment is processed into a convex shape in advance. Therefore, in the heat treatment of the subsequent step, the substrate warps in the direction opposite to the processed direction, and the substrate is flattened.

The above-described processing is performed by mechanical polishing using a polishing apparatus having a surface plate, and the shape of the surface of the substrate is changed by changing the shape of the surface of the surface of the surface plate. It will be done. The polishing apparatus used for the above processing and the actual processing conditions will be described in detail later after describing a series of steps in order to clarify the manufacturing process.

Next, a lower shield core is formed on the Al ₂ O ₃ film formed on the substrate. The lower shield core is formed by forming sendust (Fe-Al-Si) into a film having a film thickness of 1.5 μm to 3.0 μm by a method such as sputtering or plating, and then processing the film into a predetermined shape. It is formed.

In this embodiment, heat treatment is performed at a temperature of about 500 to 600 ° C. in order to stabilize the magnetic characteristics of the sendust which constitutes the lower shield core. As a result, the pre-curved substrate is warped and flattened in the opposite direction, as shown in FIG.
The Al ₂ O ₃ film 2 and the lower shield core 3 are formed on the flattened substrate 1.

Next, as shown in FIG. 2, a lead electrode 4 having a predetermined wiring pattern for supplying a current to an MR element and a bias conductor, which will be described later, is connected to the lower shield core 3 on the Al ₂ O ₃ film 2. Form in a part that does not overlap with. The lead electrode 4 is formed by Cu pattern plating having a film thickness of 1.5 μm to 3.0 μm.

As a result, as shown in FIG. 3, Al ₂ O ₃
A lower shield core 3 having a predetermined shape and a lead electrode 4 having a predetermined wiring pattern are formed on the film 2 around the lower shield core 3.

Next, in order to flatten the lower shield core 3 and the lead electrode 4, as shown in FIG. 4, a flattening film 5 made of Al ₂ O ₃ is formed on the thin shield core 3 and the lead electrode 3 having a thickness of 3 μm or more.
It is formed by sputtering to have a thickness of 6 μm.

Thereafter, the flattening film 5 is surface-polished by a mechanical polishing method using diamond abrasive grains. The plane polishing as described above is performed by the MR element or the like laminated on the lower shield core 3 in the next step and the lower shield core 3 due to a step or the like on the surface of the lower shield core 3 due to a short circuit or a disconnection defect. This is to prevent the occurrence of.

The plane polishing is performed until the lower shield core 3 and the lead electrode 4 are exposed, as shown in FIG.
This is finally performed until the thicknesses of the lower shield core 3 and the lead electrode 4 become 1 μm to 2.5 μm.

In this embodiment, since the substrate 1 is flattened as described above, the surface of the substrate 1 is uniformly contacted with the polishing platen when the surface is polished, and the substrate 1 is formed on the substrate 1. The amount of polishing of the lower shield core 3, the lead electrode 4, and the flattening film 5 becomes uniform, so that the amount of polishing of the lower shield core 3 can be regulated with high precision, and the thickness can be regulated with good precision. Therefore, the characteristics of the lower shield core 3 can be improved, and the characteristics of the manufactured MR head can be improved and stabilized.

Next, as shown in FIG. 6, a lower gap film 8 which is an insulating layer is formed on the lower shield core 3. The lower gap film 8 has a function of ensuring insulation between the lower shield core 3 and the MR element and electrodes connected thereto.
In order to have both functions as a gap film, it is desirable to use, for example, an Al ₂ O ₃ film. Here, since the lower gap film 8 is mechanochemically polished in the next step, it is thicker than a predetermined lower magnetic gap length,
The film is formed with a film thickness of about 00 nm.

Next, as shown in FIG. 7, the lower gap film 8 is formed into a predetermined thickness by a mechanochemical polishing means.
Further, the surface roughness is polished until the centerline average roughness Ra becomes 1 nm or less. The film thickness of the lower gap film 8 is directly measured by an optical measuring device.

In brief, the mechanochemical polishing means polishes suede type artificial leather or the like made of a polishing liquid in which colloidal silica (SiO ₂ ) ultrafine particles are dispersed in a weak alkaline solution, and a polyurethane foam resin. This is a method of polishing a substrate, which is an object to be polished, by combining cloths.

According to such mechanochemical polishing, the surface roughness becomes the center line due to the interaction between the mechanical polishing by SiO ₂ abrasive grains in the polishing liquid and the compound polishing combining the chemical etching by the weak alkaline solution. Mirror polishing with an average roughness Ra of about 1 nm or less is possible.

Further, in the mechanochemical polishing, the chemical polishing rate can be changed by changing the pH of the polishing liquid, and the abrasive grains in the polishing liquid are changed to, for example, diamond or ZrO ₂ . Alternatively, it is possible to change the mechanical polishing rate by changing the abrasive grain size or the abrasive grain concentration and change the overall polishing rate by changing the type of polishing cloth.

In this embodiment, since the substrate 1 is flattened, even when the mechanochemical polishing is performed as described above, the polishing amount of the lower gap film 8 can be accurately regulated, and the substrate is manufactured. The characteristics of the MR head can be improved.

Next, a contact hole (not shown) for electrically connecting the lead electrode 4 is formed in the lower gap film 8. By this step, the lower gap film 8 having a predetermined gap length, the surface roughness of the center line average roughness Ra of 1 nm or less, and the contact hole is formed.
Is formed.

Then, as shown in FIG. 8, an MR element 9 is formed on the flattened lower gap film 8. MR
In order to form the element 9, permalloy (Fe—Ni) is formed by sputtering or vapor deposition, a predetermined shape is patterned on the permalloy thin film by photolithography technique, and an unnecessary portion is removed by etching technique. Process into a predetermined shape. In this embodiment, the film thickness of the MR element 9 is 100 nm or less.

Next, as shown in FIG. 9, an insulating film 10 such as SiO ₂ is formed on the MR element 9 by sputtering in order to electrically insulate the MR element 9 from the bias conductor formed in the next step. To film. Next, as shown in FIG. 10, at the rear end 9a of the MR element 9 and the end of the lead electrode 4,
A part of the insulating film 10 is removed to form a contact hole 11 (a contact hole for a lead electrode is not shown) for electrical connection.

Then, as shown in FIG. 11, a bias conductor 12 for generating a bias magnetic field and a conductor 13 for flowing a sense current through the MR element 9 (hereinafter referred to as a rear end electrode 13) are formed. To do.

The bias conductor 12 is provided on the insulating film 10 at a position facing the MR element 9, and is formed as a strip pattern perpendicular to the longitudinal direction of the MR element 9. On the other hand, the rear end electrode 13 is partially provided on the rear end edge side of the MR element 9 so as to be laminated on the insulating film 10, and the MR element 9 is provided in the contact hole 11.
Is electrically connected to.

The bias conductor 12 and the rear end electrode 13
Considering the adhesion between the insulating film 10 and the insulating layer formed in the next step, it is desirable to have a laminated film structure in which Ti / Cu / Ti is sputtered in this order. Of course, only Cu may be used if there is no problem of adhesion.

Such a bias conductor 12 and the rear end electrode 1
3 is formed by forming a laminated thin film as described above by sputtering, patterning a predetermined shape by a photolithography technique, removing an unnecessary portion by an etching technique, and processing it into a predetermined shape.

Next, as shown in FIG. 12, an insulating layer 1 of SiO ₂ or the like is provided for insulating the bias conductor 12 and the rear end electrode 13 from the upper shield core formed in a process described later.
4 is laminated by sputtering so as to completely cover the bias conductor 12 and the rear end electrode 13.
Next, as shown in FIGS. 13 and 14, the insulating film 10 and the insulating layer 14 laminated on the tip portion 9b of the MR element 9 are removed, and the contact hole 15 exposing the tip portion 9b of the MR element 9 is removed. To form.

Next, as shown in FIG. 15, an upper gap film 16 is formed on the insulating layer 14 including the tip portion 9b of the MR element 9 facing the contact hole 15. The upper gap film 16 functions as a gap film and also functions as a tip electrode for passing a sense current to the MR element 9, and is therefore a nonmagnetic metal film such as Ti.

Subsequently, the upper shield core 17 is formed on the upper gap film 16. Like the lower shield core 3, the upper shield core 17 is formed by forming a thin film of a magnetic metal material by a method such as sputtering or plating, and then processing it into a predetermined shape.

As a result, as shown in FIG. 16, a shield type MR head, which is a reproducing head in which the MR element 9 is sandwiched between a lower shield core and an upper shield core 17 not shown in FIG. 16, is completed.

Next, an inductive head for recording is formed on the MR head. The inductive head formed here is the upper shield core 1 of the MR head.
7 is used as one recording magnetic core, so-called 3
This is a composite magnetic head with a pole structure.

To form an inductive head, first, as shown in FIG. 17, Al is formed on the upper shield core 17.
_The recording gap film 18 is formed by sputtering ₂ O ₃ . Then, a part of the recording gap film 18 is removed to form a contact hole 19 for magnetically coupling a recording magnetic core and an upper shield core 17 described later.

Next, a first flattening layer 20 made of an organic material is formed on the recording gap film 18 in order to insulate the upper shield core 17 from a recording coil described later and to obtain a flat coil forming surface. To form. Then, the recording coil 21 is spirally formed on the first flattening layer 20 by patterning Cu.

Next, in order to insulate the recording coil 21 from the recording magnetic core, which will be described later, on the recording coil 21 and to obtain a flat magnetic core formation surface, a second organic material is used. The flattening layer 22 is formed on the first flattening layer 20 and the recording coil 21.

Then, the recording magnetic core 23 is plated or sputtered with a magnetic material such as permalloy on the second flattening layer 22 and processed into a predetermined shape to complete the inductive head.

Then, a protective film 24 made of Al ₂ O ₃ or the like is formed on the recording magnetic core 23 to protect the element. Next, a connection terminal to an external circuit (not shown) is formed, and slider processing is performed to complete a composite magnetic head having a 3-pole structure.

In the composite magnetic head completed through the above steps, the lower layer reproducing magnetic gap g ₁ is formed between the lower layer shield core 3 and the MR element 9, and the upper layer shield core 17 and the MR element 9 are formed. An upper reproducing magnetic gap g ₂ is formed between the _two . And the upper shield core 1
7 and the recording magnetic core 23 between the recording magnetic gap g
₃ is formed.

In the method of manufacturing the MR head of this embodiment, various thin films are formed by sputtering as described above, or processed into various shapes by photolithography and etching techniques. At this time, since the substrate 1 is flattened, in the present embodiment, unevenness in resist coating during the photolithography process and patterning accuracy are less likely to occur, and the productivity of the MR head is improved.

Further, since the substrate 1 is flattened, the cooling effect of the substrate 1 in the sputtering or etching process is unlikely to be lowered, and the productivity of the MR head is improved.

Next, the actual processing conditions for processing the substrate 1 in advance so as to have a warp in the direction opposite to the direction of the warp generated in the substrate 1 by heat treatment will be described below together with experimental results. .

The polishing apparatus used here is, for example, as shown in FIG.
Further, as shown in FIG. 19, it is mainly composed of a surface plate 31 which functions as a polishing plate and a swinging mechanism 32 for horizontally swinging the substrate 1 placed on the surface plate 31.

The platen 31 is formed in a disk shape by, for example, hardening copper and metal particles with a polymer material. It is provided so that it can rotate in any direction. The surface roughness of the surface plate 31 is, for example, 10 μm or less. The surface of the surface plate 31 is provided with a polishing cloth 34 made of polyester nonwoven fabric, foamed polyurethane (artificial leather), or an elastic polisher having a hard-soft double structure or the like. Further, a disk-shaped substrate 1 is placed on the surface plate 31, and a jig is provided to cover the substrate 1 for the purpose of guiding the substrate 1 or applying pressure to increase the polishing rate. 35 are provided.

The jig 35 has a circular outer shape and has a circular recess 36 for fitting the substrate 1 on the surface facing the surface plate 31. The depth of the recess 36 is shallower than the thickness of the substrate 1 so that the jig 35 is not polished by the surface plate 31. Therefore, when the substrate 1 is fitted into the recess 36 and placed on the surface plate 31, only the substrate 1 comes into contact with the surface plate 31.

On the other hand, the swinging mechanism 32 includes the pair of jigs 3
A carrier 37 that rotatably holds 5; a drive motor 38 that functions as a drive source that swings the carrier 37 in the left-right direction along the center line of the surface plate 31 as indicated by arrow B in FIG. It comprises a cam 39 for converting the rotational movement of 38 into a swinging movement, a crankshaft 40, and a pair of sliders 41, 42.

The carrier 37 includes the pair of jigs 35.
Circular jig storage parts 43, 4 for rotatably storing and holding
The planar shape having 4 is formed as a so-called eyeglass-shaped support body. The carrier 37 is provided with a center roller 45 and guide rollers 46, 47 for rotatably storing and holding the jigs 35 stored in the jig storing portions 43, 44. The center roller 45 is rotatably provided as a disc body between the pair of jig accommodating portions 43 and 44. Further, the guide rollers 46 and 47 are rotatably provided as cylindrical rollers around the outer circumferences of the jig accommodating portions 43 and 44 on the opposite side of the center roller 45.

On both sides of the carrier 37, sliders 41 and 42 for swinging the carrier 37 in the left-right direction are provided. That is, sliders 41 and 42 are provided at both ends of the carrier 37 so as to be slidable on the apparatus main body 33 via the columnar connecting members 50 and 51. These sliders 4
One of the sliders 41, 42 has a cam 39 for converting the rotational movement of the drive motor 38 into a swinging movement.
And a crankshaft 40 are provided. Therefore, the rotational movement of the drive motor 38 is transmitted to the cam 39 and converted into swinging movement by the crankshaft 40 engaging with the cam 39. As a result, the carrier 37 swings in the left-right direction. The above carrier 3
The rocking speed of 7 can be appropriately adjusted by the control device 52 provided on the device body 33.

In the polishing apparatus used in this embodiment, the surface plate 31 has different shapes on the inner and outer circumferences. That is, as the surface plate 31, one having an outer peripheral side thickness as shown in FIG. 20 which is thicker than the inner peripheral side and the polishing surface 31a is a concave inclined surface, or an inner peripheral side as shown in FIG. Of the polishing surface 31 is thicker than the thickness of the outer peripheral side.
The one in which a is a convex inclined surface is used.
Then, in order to make the substrate 1 concave as shown in FIG. 23 (A), a platen 31 as shown in FIG. 21 in which the polishing surface 31a is a convex inclined surface may be used. On the other hand, to make the substrate 1 convex as shown in FIG.
It is sufficient to use a surface plate 31 whose polishing surface 31a as shown by 0 is a concave inclined surface.

As described above, in order to make the polishing surface 31a of the surface plate 31 an inclined surface, the polishing surface 31a of the surface plate 31 is mechanically formed by using, for example, a diamond electrodeposition ring on which diamond is electrodeposited. It should be polished to. That is, the diamond electrodeposition ring is fixed to one point of the polishing surface 31a of the surface plate 31, and the diamond electrodeposition ring is rotated. At this time, the surface plate 31, which is a copper Kemet surface plate obtained by solidifying copper and metal particles with a polymer material, is easily ground by diamond.

When it is desired to increase the thickness of the surface plate 31 on the outer peripheral side to make the polishing surface 31a concave, a diamond electrodeposition ring may be installed on the inner peripheral side for polishing.
The polishing rate on the inner peripheral side of the surface plate increases, the inner peripheral side is further polished and the outer peripheral side becomes thicker, and the polishing surface 31a becomes a concave inclined surface. Further, when it is desired to increase the thickness of the inner surface of the surface plate 31 to make the polishing surface 31a convex, it is sufficient to install a diamond electrodeposition ring on the outer surface side and perform polishing. The polishing rate increases, the outer peripheral side is more polished, the inner peripheral side becomes thicker, and the polishing surface 31a becomes a convex inclined surface. If the material is not limited to diamond and is harder than the surface plate 31, the above grinding process can be performed.

To polish the substrate 1 using the polishing apparatus having the above-described structure, first, the substrate 1 is placed on the surface plate 31 so that the polishing surface is in contact with the surface plate 31. Next, the jig 35 is dropped on the substrate 1. Then, the substrate 1 is fitted into the recess 36 provided in the jig 35, the position of the substrate 1 is determined, and at the same time, the load is applied to the substrate 1.

Since the substrate 1 and the jig 35 are not bonded with wax or an adhesive, warpage or waviness of the substrate due to adhesive distortion does not occur, and uneven wear does not occur during polishing.

Next, these jigs 35 are set in the jig accommodating portions 43 and 44 provided in the carrier 37. As a result, the jig 35 moves to the center roller 45 and the guide roller 4
6, 47 and rotatably held.

Next, the surface plate 31 is rotated and the drive motor 38 is turned on. Then, the rotation of the drive motor 38 is transmitted to the cam 39, and is converted into a swing motion by the crankshaft 40 connected to the cam 39. Then, one slider 41 and the other slider 4 connected to the crankshaft 40
2 causes the carrier 37 to swing in the left-right direction. As a result, the jig 35 and the substrate 1 which are rotatably held by the carrier 37 also swing together with them.

Then, the diamond slurry is supplied onto the surface plate 31 from the tip of the nozzle 49 connected to the polishing liquid supply tank 48. Then, the substrate 1 is polished over the entire substrate by the rotating motion of the surface plate 31 and the swinging motion of the carrier 37. When the substrate 1 is not swung, uneven wear occurs in the central portion of the substrate 1 due to the difference in peripheral speed between the inner and outer circumferences of the substrate 1.

Next, using the above-mentioned polishing apparatus, the actual processing conditions for processing the substrate 1 so as to have a warp in the opposite direction to the warpage caused by the heat treatment in advance were investigated. That is, as shown in FIG. 20 or 21, the surface plate 31 has a radius R of 190 mm, and the position r ₁ = 180 mm (outer peripheral side) and r _{2 in the} radial direction from the center.
= Polishing surface 31 between the positions of 97.5 mm (inner peripheral side)
The degree of inclination of a was changed, and the relationship between the height difference t between the inner peripheral side and the outer peripheral side of the polishing surface 31a and the flatness of the substrate 1 when polishing was performed using this surface plate was investigated.

The height difference t of the surface plate 31 is defined with reference to the outer peripheral side. On the other hand, the flatness of the substrate 1 is defined as the difference between the maximum height and the minimum height when the polishing surface of the substrate 1 is measured at a measurement distance of 90 mm using a stylus type surface roughness measuring instrument. The case where the surface is convex is expressed as positive, and the case where the surface is concave is expressed as negative.

The results are shown in FIG. In FIG. 22, the horizontal axis represents the height difference h, and the vertical axis represents the substrate flatness. The surface of the polished substrate 1 opposite to the polishing surface has a warp in the opposite direction to the polishing surface. If the polishing surface is convex, the opposite surface is concave, and the polishing surface may be concave. For example, the opposite surface was convex.

As can be seen from FIG. 22, when the outer peripheral side of the surface plate 31 is raised, the polished surface of the substrate 1 after polishing becomes convex. This is because the peripheral speed of the substrate 1 is higher on the outer peripheral side,
This is because the outer peripheral side of the substrate 1 is easily polished. Further, when the inner peripheral side of the surface plate 31 is raised, the inner peripheral side of the substrate 1 is easily polished, so that the polished surface of the substrate 1 after polishing becomes concave. Then, it was found that in order to make the polished surface of the substrate 1 flat, that is, to make the flatness zero, the inner peripheral side of the surface plate 31 should be lower than the outer peripheral side by about 4 μm.

It was also found that the polishing surface of the substrate 1 after polishing was not flat when the surface plate 31 having a height difference h between the inner circumference side and the outer circumference side of zero was used. this is,
It is considered that this is caused by the difference in polishing speed due to the difference in peripheral speed between the inner and outer peripheries of the platen 31, the swing range, and the like.

As described above, by changing the shape of the surface plate 31, the shape of the substrate 1 can be changed, and the substrate 1 has a warp in a direction opposite to the direction of the warp caused by the heat treatment in advance. Can be processed as follows.

The direction and amount of the warp that occurs when the substrate 1 is heat-treated at 500 to 600 ° C. is generally known.
Therefore, for example, the substrate 1 having a warp amount of 1 μm and being warped in a convex shape by heat treatment may be processed into a concave shape having a warp amount of 1 μm. On the other hand, the substrate 1 having a warp amount of 1 μm and being warped in a concave shape by heat treatment may be processed into a convex shape having a warp amount of 1 μm. In this way, the substrate 1 after the heat treatment is flattened.

In this embodiment, the substrate 1 made of alumina titanium carbonate was used, but the material forming the substrate 1 is not limited to this. The processing conditions of the substrate 1 may be changed as appropriate depending on the constituent material and size of the substrate 1, the wafer process and its process capability.

[0083]

As is apparent from the above description, according to the present invention, after the lower shield core made of sendust is formed on the substrate made of ceramics, the substrate is heat-treated to insulate the lower shield core. A magnetoresistive effect element is provided via a layer, and an upper shield core made of a magnetic material is formed on the magnetoresistive effect element via an insulating layer.
It is processed in advance so as to have a warp in a direction opposite to the direction of the warp caused by the heat treatment after forming the lower shield core. That is, in the above heat treatment, the substrate warps in the direction opposite to the processed direction, and the substrate is flattened. Therefore, the lower shield core formed on the substrate does not warp, and the characteristics of the manufactured magnetoresistive head can be improved and stabilized.

Further, in the method of manufacturing the magnetoresistive effect magnetic head of the present invention, since the substrate is flattened,
When various types of polishing are performed during the manufacturing process, it is possible to accurately control the amount of polishing, and it is possible to improve and stabilize the characteristics of the manufactured magnetoresistive head.

Further, in the method of manufacturing the magnetoresistive effect type magnetic head of the present invention, since the substrate is flattened, various thin films are formed by sputtering in the manufacturing process, or by the photolithography technique and the etching technique. Even when processed into various shapes, uneven coating of the resist during the photolithography process and reduction in patterning accuracy are less likely to occur, and the cooling effect of the substrate during sputtering and etching processes is less likely to occur. Head productivity is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a step of manufacturing an MR head in order, showing a state in which an Al ₂ O ₃ film and a lower shield core are formed on a substrate.

FIG. 2 is a cross-sectional view showing a lead electrode forming step, showing the manufacturing steps of the MR head in order.

FIG. 3 is a plan view showing a lead electrode forming step, showing the manufacturing steps of the MR head in order.

FIG. 4 is a cross-sectional view showing a step of forming a flattening film, showing the manufacturing steps of the MR head in order.

FIG. 5 is a cross-sectional view showing a plane polishing step, showing the manufacturing steps of the MR head in order.

FIG. 6 is an enlarged sectional view of an essential part showing a step of forming a lower layer gap film, showing the manufacturing steps of the MR head in order.

FIG. 7 is a fragmentary enlarged cross-sectional view showing a step of polishing the lower gap film by mechanochemical polishing, showing the manufacturing steps of the MR head in order.

FIG. 8 is a flow chart showing the manufacturing process of the MR head.
It is a principal part expanded sectional view which shows an element formation process.

FIG. 9 is a cross-sectional view showing an insulating film forming step, showing the manufacturing steps of the MR head in order.

FIG. 10 is a cross-sectional view showing a step of forming a contact hole, showing the manufacturing steps of the MR head in order.

FIG. 11 is a cross-sectional view showing a step of forming a bias conductor, showing the manufacturing steps of the MR head in order.

FIG. 12 is a cross-sectional view showing an insulating layer forming step in the order of manufacturing steps of the MR head.

FIG. 13 is a cross-sectional view showing a step of forming a contact hole, showing the step of manufacturing the MR head in order.

FIG. 14 is a plan view schematically showing the step of forming a contact hole, showing the manufacturing steps of the MR head in order.

FIG. 15 is a cross-sectional view schematically showing the manufacturing process of the MR head and schematically showing the upper shield core forming process.

FIG. 16 is a plan view schematically showing the manufacturing process of the MR head, and schematically showing the upper shield core forming process.

FIG. 17 is an enlarged cross-sectional view of a main part of a composite magnetic head in which an inductive head is laminated on an MR head.

FIG. 18 is a plan view of the polishing apparatus.

FIG. 19 is an enlarged side view showing the polishing device partially broken away.

FIG. 20 is a sectional view showing an example of a surface plate.

FIG. 21 is a cross-sectional view showing another example of the surface plate.

FIG. 22 is a characteristic diagram showing the relationship between the height difference h and the substrate flatness.

FIG. 23 is a side view showing the processed substrate.

[Explanation of symbols]

 1 Substrate 3 Lower Shield Core 8 Lower Gap Film 9 MR Element 10 Insulating Film 14 Insulating Layer 17 Upper Shield Core

Claims (3)

[Claims] 1. A lower layer shield core made of sendust is formed on a substrate made of ceramics, the substrate is heat-treated, and a magnetoresistive element is provided on the lower shield core via an insulating layer. In a method of manufacturing a magnetoresistive effect magnetic head in which an upper shield core made of a magnetic material is formed on an effect element through an insulating layer, the substrate is formed in a direction opposite to a warp direction caused by a heat treatment after forming the lower shield core. A method of manufacturing a magnetoresistive effect magnetic head, characterized in that it is processed so as to have a warp in a direction in advance. 2. A method of manufacturing a magnetoresistive effect magnetic head according to claim 1, wherein a thin film made of alumina is formed on the substrate. 3. The method of manufacturing a magnetoresistive effect magnetic head according to claim 1, wherein the ceramic is alumina titanium carbonate.