JP3538306B2 - Thin film magnetic head and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head and a method of manufacturing the same, and more particularly, to an MR element or GM.
The present invention relates to a configuration suitable for a thin-film magnetic head using an R element and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a general magnetic disk drive, FIG.
As shown in FIG. 1, the magnetic head 1 is fixed to a support spring 4 such that the flying surface 3 faces the magnetic disk 5. The magnetic head 1 flies above the rotating magnetic disk 5, and performs writing and reading of magnetic recording by the thin-film magnetic transducer 2 of the magnetic head 1. The driving device 6 includes the magnetic head 1
Is moved in the radial direction of the magnetic disk 5.

In a magnetic disk drive in which recording density is dramatically improved, it is necessary to reduce the flying height of a magnetic head with respect to a magnetic recording medium in accordance with the improvement in recording density. Currently, the flying height of the head is described in "Nikkei Mechanical" 5 /
No. 27 no.481 (1996)
It is said that m.

A general manufacturing process of such a magnetic head will be described with reference to FIGS. 3 (a), 3 (b) and 3 (c). First, the thin-film magnetic transducers 2 are formed at predetermined intervals on the wafer-shaped substrate 101 made of Altic, zirconia, or the like using lithography technology (FIG. 3A).
As a layer configuration of the thin-film magnetic transducer 2, as shown in FIG.
Lower protective film 10a, lower shield film 13, insulating film 105
MR element 14 for reproduction, upper shield film 12,
A configuration in which a recording inductive element 9 and an upper protective film 10b are stacked is general. This wafer-shaped substrate 101 is cut into a plurality of bars 102 (FIG. 3B). After the cutting distortion after cutting is removed by grinding or double-sided lapping or the like, the surface serving as the floating surface of the magnetic head is polished with high precision. Then, a protective film 104 made of hydrogen-containing amorphous carbon or the like is formed on the surface serving as the floating surface of the bar 102 (FIG. 3C).
The protective film 104 prevents the thin-film magnetic transducer 2 and the magnetic disk 5 from directly colliding with each other and prevents corrosion of the magnetic film constituting the MR or GMR element disposed in the magnetic head 1. Is formed. Furthermore,
A rail 103 is formed on the surface serving as the floating surface of the bar 102 in consideration of the floating characteristics (FIG. 3D). Finally, bar 1
02 is cut into chips to complete the magnetic head 1 (FIG. 3).
(E)).

In such a process, as a method of polishing the surface serving as the floating surface of the bar 102 in FIG. 3B, lapping for polishing on a soft metal surface plate is used. Specifically, a soft metal platen 1 that rotates as shown in FIG.
The bar 102 mounted on the polishing jig 17 is pressed and slid while dropping a lapping liquid 16 containing abrasive grains such as diamond on the polishing pad 15. In this method, a part of the abrasive grains of the lapping liquid 16 is embedded in the surface plate 115 to form fixed abrasive particles, and a part of the abrasive particles becomes rolling abrasive particles that roll between the surface plate 115 and the bar 102. Then, each of the air bearing surfaces is polished.

As the structure of the protective film 104, a single-layer protective film made of silicon-containing amorphous carbon or the like, or a two-layer protective film of an adhesive layer and a protective layer is known. As a protective film having a two-layer structure, Si or SiO ₂ is used for the adhesive layer, and hydrogen-containing amorphous carbon or the like is used for the protective layer. Si
The method of forming the adhesive layer of SiO ₂ or SiO ₂ is based on the Si target or Si
A sputtering method of sputtering an O ₂ target with Ar gas is used. To form a protective layer of hydrogen-containing amorphous carbon, a graphite target is formed with hydrogen and Ar.
Reactive sputtering for sputtering with a mixed gas of, or CVD for decomposing hydrocarbon-based gas with high-frequency plasma
(Chemical Vapor Deposition
The n) method is used.

[0007] In any case of the protective film 104,
Since the magnetic film used for the MR element and the GMR element is very easily corroded, the thickness of the protective film 104 has conventionally been required to be about 7 to 10 nm or more from the viewpoint of preventing corrosion.

In Japanese Patent Application Laid-Open Nos. 62-292358 and 7-299737, in order to reduce processing steps and scratches on the floating surface of a magnetic head, free abrasive grains are cut into a surface plate. A polishing method in which abrasive grains are fixed to a surface plate and polished only with a diluent or a lubricant is disclosed.

[0009]

In order to reduce the flying height of the magnetic head 1, it is necessary to reduce the thickness of the protective film 104 disposed on the flying surface. However,
The conventional magnetic head 1 has a problem that the protective film 104 cannot be thinner than 7 nm in order to prevent corrosion of the MR element and the GMR element.

When the air bearing surface is polished by a polishing method using a lapping liquid in a conventional magnetic head, as shown in FIG. 5, a processing step 8 caused by a difference in processing efficiency between different materials.
This causes a problem that reduction of the flying height is hindered.

An object of the present invention is to provide a configuration of a thin-film magnetic head capable of preventing corrosion of an MR element and reducing the thickness of a protective film.

[0012]

According to the present invention, there is provided the following thin-film magnetic head.

More specifically, the substrate has a thin-film magnetic transducer mounted on the substrate, and the end faces of the substrate and the thin-film magnetic transducer constitute an air bearing surface facing a magnetic recording medium. The magnetic transducer has one or more magnetic films, and the surface roughness of the air bearing surface is 2 nm or less in Rmax at the end surface of the magnetic film, and the surface roughness of 7 nm or less is provided on the air bearing surface. A thin film magnetic head having a protective film disposed thereon.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The present inventors have proposed an MR element and a GMR
We focused on the relationship between element corrosion and surface roughness of the air bearing surface of the magnetic head.

When the polishing is performed by a conventional polishing method using a lapping liquid, the surface roughness of the air bearing surface becomes coarse, and scratches such as the scratch 21 shown in FIG. 6 also occur. The reason why the surface roughness is increased in this way is that rolling abrasive grains that roll between the surface plate and the air bearing surface are present. When the surface roughness of the air bearing surface is rough, the inventors generate a portion 202 where the film thickness of the protective film 104 formed on the air bearing surface becomes thin as shown in FIG. It is presumed that corrosion of the magnetic transducer element occurs from this portion 202 because of insufficient resistance.

The inventors prepared samples of magnetic heads having various surface roughnesses of the air bearing surface, and measured the thickness of the protective film and the MR head.
By examining the relationship with the element corrosion, FIG.
As described above, it was found that there was a surface roughness where the rate of occurrence of corrosion sharply decreased.

Hereinafter, this will be described.

The configuration of the magnetic head used for examining the relationship between the thickness of the protective film and the corrosion of the MR element is as shown in FIGS. That is, on the substrate 101,
As the thin-film magnetic transducer 2, a lower protective film 10a, a lower shield film 13, an MR element for reproduction 14 sandwiched between insulating films 105, an upper shield film 12, an inductive element for recording 9, and an upper protective film 10b are laminated in this order. Configuration. Further, a protective film 104 is formed on the air bearing surface. In this embodiment, the substrate 101 is made of alumina titanium carbide, the protective film 10 is made of alumina, the upper magnetic film 11 and the upper shield film 12 of the recording inductive element 102 are made of an Fe—Ni alloy, and the lower shield film is made of Fe—Ni alloy. 13 is a 2 μm thick CoNbZ
It is composed of an r film. The MR element 14 is made of Fe-N
An i-alloy layer or the like is laminated, and the total thickness of the element is 20 nm. MR element 14 and upper and lower shield films 1
The insulating film 105 between layers 2 and 13 was formed of an alumina film having a thickness of 120 nm.

Since the MR element 14 is very thin,
Since it is difficult to inspect whether or not corrosion has occurred in the MR element, the occurrence of corrosion in the upper magnetic film 11 and the upper shield film 12 formed of a material less corrosive than the MR element is detected, and If corrosion is occurring,
It was determined that the MR element was also corroded. The surface roughness of the air bearing surface is optimally determined based on the surface roughness of the end face of the MR element 14 in which the occurrence of corrosion is a problem. However, since the MR element 14 has a small thickness, it is difficult to measure. Therefore, the surface roughness of the end faces of the upper magnetic film 11 and the upper shield film 12 was measured. The roughness of the end face of the MR element 14 is such that the hardness of the material is such that the upper magnetic film 11 and the upper shield film 1 are hard.
Since the hardness is about the same as that of No. 2, it can be estimated that the hardness is about the same. Films other than the magnetic film, such as the substrate 101 and the protective films 10a and 10b, are made of a material harder than the magnetic film, so that the surface roughness is smaller than that of the upper magnetic film 11, and the surface roughness is the lowest among the floating surfaces. Rough parts are magnetic films such as the upper magnetic film 11 and the MR element 14.

Next, a method of manufacturing a sample of the magnetic head 1 according to the present embodiment will be described.

In the present embodiment, samples of the magnetic head 1 having variously changed air bearing surface roughness are manufactured in order to investigate the relationship between the roughness of the air bearing surface, the thickness of the protective film, and the corrosion of the MR element. There is a need to. However, in the polishing method using the conventional lapping liquid, there is a limit in reducing the surface roughness. Further, in the polishing method using the lapping liquid, if the particle size of the abrasive grains is reduced in order to reduce the surface roughness, there is a problem that the processing step 8 (FIG. 5) of the floating surface increases. Therefore, in this embodiment, the polishing method using the lapping liquid was not used.

A polishing method described in JP-A-62-292358 and JP-A-7-299737, in which polishing is performed using only a diluting liquid or a lubricant by using a platen into which abrasive grains have been cut, The surface roughness can be reduced to some extent, and the processing step can be reduced. However, in the methods described in these publications, in order to secure the holding force of the abrasive grains on the surface plate, the particle size needs to be 0.5 μm to 1.0 μm, and the particle size is 0.5 μm or less. Cannot be fixed to the surface plate. With a surface plate on which abrasive grains having a particle size larger than 0.5 μm are fixed, the surface roughness of the upper magnetic film 11 on the air bearing surface cannot be made smaller than 6 nm.

Therefore, in the present embodiment, a platen in which abrasive grains having a particle size of 0.5 μm or less are cut into the platen is manufactured by using a unique platen manufacturing method invented by the inventors. By polishing the flying surface using this, a magnetic head sample having a flying surface with a surface roughness of 6 nm or less was made possible. As a result, even in a range where the surface roughness is small, the relationship between the thickness of the protective film and the corrosion can be measured.

More specifically, a method of manufacturing the magnetic head 1 according to the embodiment will be described.

First, a method of manufacturing a surface plate used for polishing the flying surface will be described.

As shown in FIG. 7, the platen 15 is
The surface of the surface plate 15 is processed according to the shape of the air bearing surface of the magnetic head 1. At this time, lapping machine 11
As 01, a lapping machine used in a polishing step of the flying surface of the magnetic head 1 is used. The next step of embedding abrasive grains is also performed on the lapping plate 1101 so that the surface plate 15 is not transferred from the lapping plate 1101 to another processing table or the like until polishing of the air bearing surface is completed. Thereby, the deformation of the surface plate 15 due to the transfer of the surface plate 15 can be prevented, so that the contact state between the jig and the surface plate 15 in the step of embedding abrasive grains can be kept good.

As the material of the surface plate, a material is used in which the abrasive grains are easily embedded and held, and the amount of projection of the abrasive particles from the surface of the surface plate is easy to be uniform. In this embodiment, a tin surface plate is used. In addition to tin, soft metal tin, tin-copper alloy, tin-
A lead alloy or the like can be used. The processing shape of the surface of the surface plate is determined according to the air bearing surface of the magnetic head. In the present embodiment, it is processed into a perfect plane. As the processing conditions, using a diamond tool 23 having a tip radius of 0.1 mm, the platen rotation speed 200 rpm, the feed rate 25 mm / min, the cutting depth 20 μm / 1p
ass. In this embodiment, the surface is processed into a flat surface. However, the surface can be processed into a desired shape according to the shape of the floating surface of the thin film magnetic head to be polished. For example, when a crown is formed on the air bearing surface of a thin-film magnetic head, the shape of the surface plate is corrected in advance to a spherical surface.

Next, a step of embedding abrasive grains in the surface plate 15 and fixing the abrasive particles to the surface plate 15 is performed. The particle size of the abrasive grains to be embedded is determined according to the surface roughness of the floating surface to be formed. Abrasive particles having a particle size of 0.5 μm or less, particularly abrasive particles having a particle size of 0.1 μm or less, have a small holding force with respect to the surface plate, and therefore, it is difficult to fix the particles to the surface plate. This is made possible by preventing the surface plate from being deformed, maintaining good adhesion between the surface plate 15 and the embedding jig, and performing the following pretreatment process.

This pretreatment step is a step for improving the flatness and surface roughness of the surface of the surface plate 15. Specifically, the platen 15 is rotated by the lapping machine 1101, and the nonwoven fabric attached to the jig is pressed and slid for a predetermined time while the slurry in which the abrasive grains are dispersed is dropped. As a result, the burrs generated in the previous step of processing the surface plate are removed, the flatness of the surface of the surface plate is increased, and the surface roughness is reduced. Specifically, by this step, the surface roughness of the surface of
The pre-processing is performed under the condition that the protrusions of the processing traces in the previous processing step become 0.1 μm or less. The reason for using a non-woven fabric is that the non-woven fabric has elasticity, so that it can easily hold the abrasive grains and easily follow the surface of the surface plate. Thus, the surface plate 15
By improving the flatness and surface roughness of the surface of the above, in the subsequent abrasive grain embedding process, the adhesion between the jig and the surface plate can be further improved. Of fine abrasive grains can be embedded. The same slurry as that used in the next abrasive grain embedding step is used. In this embodiment, the nonwoven fabric is a polishing cloth (IC60 manufactured by Rodel Nitta or suba).
800) was used. The platen rotation speed was 30 rpm, and the rotation time was 30 minutes to 60 minutes.

Next, as a step of embedding abrasive grains, while the slurry in which the abrasive grains are dispersed is dropped, the platen 15 is rotated, and the embedding jig is pressed and slid, so that the free abrasive in the diamond slurry is removed. The grains are pressed against the surface of the surface plate 15 and embedded in the surface of the surface plate 15. A member having no elasticity is used as the embedding jig. In the present embodiment, a ceramic correction ring such as alumina or ferrite is used as an embedding jig. At this time, since the flatness and surface roughness of the surface of the surface plate have been improved by the pretreatment process, the embedding jig and the surface of the surface plate are in close contact,
Free abrasive grains of 0.5 μm or less can be embedded. The rotation speed of the platen 15 is suitably 30 to 60 rpm. Further, in the present embodiment, the abrasive grains are embedded for about 1 to 6 hours. The surface pressure applied from the embedding jig to the surface plate 15 is set to an appropriate pressure determined in advance by experiments. In the present embodiment, only the surface pressure due to the own weight of the correction ring is used.
If the diameter of the mounting jig such as a correction ring is small,
Slide while moving in the radial direction of the surface plate 15.

In the present embodiment, a slurry in which ethylene glycol is used as a solvent and abrasive grains having a predetermined particle size are dispersed therein is used. Single crystal diamond was used as the material of the abrasive grains. In addition, as a solvent, glycol ether, polyalkylene glycol, polyoxyethylene alkyl ether, or the like can be used. Since these have an appropriate specific gravity, the abrasive grains can be dispersed to form a slurry. However, ethanol or acetone can also be used as the solvent. Since these solvents have a small specific gravity, the abrasive grains cannot be dispersed to form a slurry. However, the abrasive grains are dispersed on the surface of the surface plate 15 in advance, and the solvent is dropped on the slurry to form a slurry. As in the case, a pretreatment step and an abrasive grain embedding step can be performed.

Next, a cleaning step for removing free abrasive grains remaining without being embedded in the surface of the surface plate 15 is performed. If loose abrasive particles remain on the surface of the surface plate 15,
When the surface of the head is polished, the free abrasive grains become rolling abrasive grains that roll between the air bearing surface and the surface plate 15, causing damage to the air bearing surface and causing a processing step. is there.
First, the platen 15 is washed away with a detergent and water. However, this alone cannot sufficiently remove the free abrasive grains remaining without being embedded, and further, as shown in FIG.
While applying the same solvent as the solvent used for the slurry in the embedding process to the surface plate 15, the surface of the surface plate 15 is wiped off with a cloth or a nonwoven fabric. As a result, the abrasive grains 24 not sufficiently held by the surface plate 15 can be removed, and only the completely fixed abrasive particles 20 embedded in the surface plate 15 can be left on the surface plate 15 (FIG. 9). (B)). The surface condition of the surface plate after this wiping process has not changed much from the surface of the surface plate before embedding the abrasive grains, but the state close to the mirror surface before embedding is matte because the abrasive particles are You can see that it is embedded.

When the same solvent as that used in the embedding step using the same solvent as the slurry is used for wiping in the washing step, the abrasive grains that have not been embedded most effectively can be removed. For example, in the present embodiment, since ethylene glycol is used as a solvent for the slurry, wiping is performed with ethylene glycol. It is considered that the reason why free abrasive grains can be effectively removed by using the same solvent as the solvent of the slurry is that the solvent molecules are bonded to the surface of the abrasive grains when the slurry is formed. For this reason, with water or detergent, the solvent molecules on the surface of the abrasive grains repel water and the detergent, and the abrasive grains cannot be removed effectively. However, a solvent having a property of attracting the solvent molecules of the slurry bonded to the abrasive grains. Can be effectively removed. Examples of the solvent having such a property as to attract the solvent molecules of the slurry include a solvent having a group similar to the group of the molecules bonded to the abrasive grains. for that reason,
By removing the abrasive grains with the same solvent as the solvent used for the slurry, the abrasive grains having molecules of the slurry solvent bonded thereto can be easily removed from the surface plate. In the case where the abrasive and the abrasive such as acetone and ethanol are separately dropped on the surface plate without using the slurry in the abrasive grain embedding step, the abrasive is removed with the same solvent as the solvent dropped at the time of embedding. It can be carried out.

It should be noted that even if the solvent is not exactly the same as the solvent used at the time of embedding, another solvent having a group that attracts the group at the tip of the solvent molecule bonded to the abrasive may be used for removing the abrasive. It is possible. Such a solvent can be selected by design or experiment in consideration of attractive force and compatibility between molecules.

Through the above steps, a platen on which abrasive grains having a particle diameter of 1/2 μm are fixed, a platen on which abrasive grains having a particle diameter of 1/4 μm are fixed, a platen on which abrasive grains having a particle diameter of 1/8 μm are fixed, Particle size 1/1
A platen on which 0 μm abrasive particles were fixed and a platen on which abrasive particles having a particle size of 1/15 μm were fixed were produced.

In the pretreatment step of embedding the abrasive grains, a nonwoven fabric is used in the present embodiment. However, the present invention is not limited to the nonwoven fabric, and another material having elasticity and easily following the surface of the surface plate is used. You can also. For example, silicon rubber or the like can be used.

Next, a method of manufacturing the magnetic head 1 using these surface plates will be described.

As described above, the thin-film magnetic head manufactured according to the present embodiment includes the thin-film magnetic transducer 2 having the layer configuration shown in FIGS.

First, the thin-film magnetic transducers 2 are formed on the wafer-shaped substrate 101 at predetermined intervals by using lithography (FIG. 3A). Specifically, the substrate 1
01, a lower protective film 10a, a lower shield film 13,
The MR element for reproduction 14, the upper shield film 12, the inductive element 9 for recording, and the upper protective film 10b are formed in this order between the insulating films 105.

The wafer-shaped substrate 101 is cut into a plurality of bars 102 (FIG. 3B). After the cutting distortion after cutting is removed by grinding or double-sided lapping or the like, the surface serving as the floating surface of the magnetic head is polished with high precision. This polishing is performed by using any one of the surface plates 15 manufactured by the method described above and having a particle size.
It is performed by pressing the thin film magnetic head against the surface plate 15 with a predetermined surface pressure by a polishing jig while rotating by 101 and dropping only the lubricant containing no abrasive grains.
In the present embodiment, the dripping speed of the lubricant is set to 1-2 cc / m.
The rotation speed of the platen 15 was set to a low speed rotation of 10 to 30 rpm.

In this embodiment, the abrasive grains 20 are fixed by being embedded in the surface plate 15 (FIG. 7).
(B)). For this reason, when compared with the conventional method of supplying the lapping liquid onto the surface plate 115 (FIG.
(FIG. 7 (b)) shows that the amount of protrusion (projection amount) of the abrasive grains 20 protruding from the surface plate 15 is uniform, and that the rolling abrasive particles roll between the surface plate 15 and the magnetic head 1. Since there is no 119, the cut amount 22 for the magnetic head 1 can be made smaller than the cut amount 122 when the conventional lapping liquid is used, and the variation in the cut amount for each abrasive grain can be reduced. Thus, the roughness of the entire polished surface can be made smooth, and the number of scratches 21 on the polished surface can be reduced.

The platen 15 of the present embodiment has a particle size of 1
/ 62μm or less embedded abrasive grains.
When compared with a surface plate in which abrasive grains having a large particle diameter are fixed as described in Japanese Patent Application Laid-Open No. 292358/1995 and Japanese Patent Application Laid-Open No. 7-299737, the surface plate 15 of the present embodiment has:
Since the fixed particle size is small, the protrusion amount of the abrasive grains is smaller than that of the conventional platen. For this reason, it is possible to further reduce the roughness of the polished surface as compared with the conventional fixed abrasive platen.

A platen on which abrasive grains having a particle diameter of 1/2 μm are fixed, a platen on which abrasive grains having a particle diameter of 1/4 μm are fixed, a platen on which abrasive grains having a particle diameter of 1/8 μm are fixed, a particle diameter of 1/10 μm FIG. 10 shows the relationship between the surface roughness of the air bearing surface of the magnetic head sample polished by the surface plate having the fixed abrasive grains and the surface plate having the abrasive particles having a diameter of 1/15 μm fixed thereto, and the abrasive particle diameter. As described above, the surface roughness of the air bearing surface is measured at the end surface of the upper magnetic film 11 because it is difficult to measure the end surface roughness of the MR element 14. Measurements were made using an atomic force microscope (AFM) (Degit
al Instrument). The tip of the AFM was made of silicon and had a tip radius of 10 to 30 nmR. The scanning distance was 10 μm. From FIG. 10, it can be seen that the surface roughness sharply decreases at a boundary of the grain size of the abrasive grains embedded in the surface plate of 0.1 μm. Further, when the position of the scratch 21 on the air bearing surface was confirmed by the AFM measurement, it was found that the scratch 21 on the air bearing surface was not generated when the particle size of the abrasive grains was 1/10 μm or less.

Further, the processing steps on the air bearing surface when the type of the lubricant used for polishing was changed were measured. Figure 1 shows the results.
It is shown in FIG.

When a hydrocarbon solvent, which is a non-aqueous solvent, is used as a lubricant, the upper magnetic film 11
It can be seen that the recess is smaller than 0a and the processing step becomes smaller as the grain size of the abrasive grains becomes smaller, and becomes almost 0 when the grain size is 1/10 μm or less.

On the other hand, when ethylene glycol, which is a water-soluble solvent, is used as a lubricant, as shown in FIG. 12, the grain size of the abrasive grains is 1/8 μm, the machining step is 0, and 1/8 μm
If it is larger, the upper magnetic film 11 is recessed than the protective film 10a.
0a. For this reason, when using a surface plate on which abrasive grains having a particle size of 1/10 μm or less are fixed, the upper magnetic film 11 protrudes from the protective film 10a and the upper shield film 12 made of the same material as the upper magnetic film 11 also protrudes. Since a phenomenon occurs, thermal aspirity may be caused when the thin film magnetic head is used, which is not preferable. This upper magnetic film 1
The phenomenon in which 1 protrudes from the protective film 10a also occurs when other water-soluble solvents such as ethylene glycol and polyethylene glycol having a molecular weight of 200 or 400 or polyalkylene glycol are used as the lubricant.

The protruding end faces of the upper magnetic film 11 and the upper shield film 12 as described above cause the aqueous solvent to be adsorbed on the end faces of the upper magnetic film 11 and the upper shield film 12 and reduce the polishing efficiency of the adsorbed portions. In addition, it is considered that the water-based solvent has an etching effect on the alumina of the protective film 10.

From these facts, it was found that a water-insoluble lubricant was suitable as a lubricant at the time of polishing. Therefore, in the present embodiment, a water-insoluble lubricant was used to prepare a magnetic head sample. The air bearing surface was polished.

After the polishing of the air bearing surface was completed, a protective film 104 was formed on the surface of the bar 102 to be the air bearing surface (FIG. 3).
(C)). No. 1 in Table 1 is used as the protective film 104. 1
-No. 7, any one of the seven types of protective films was formed. The protective films 104 of No. 1 to No. 6 in Table 1 have a two-layer structure of an adhesive layer as a base layer and a protective layer thereon. The adhesive layer is formed to improve the adhesion between the protective layer and the air bearing surface and prevent the protective film from peeling off. In the present embodiment, each of the adhesive layers is formed of amorphous silicon. No1
The protective layers of the protective films No. to No. 3 were formed of hydrogen-containing amorphous carbon. The protective layer of the protective film of No. 4 was formed of silicon-containing amorphous carbon (including hydrogen). The protective layer of the protective film of No. 5 was formed of fluorine-containing amorphous carbon (including hydrogen). The protective layer of the protective film of No. 6 was formed of nitrogen-containing amorphous carbon (including hydrogen). The protective film of No. 7 did not form an adhesive layer, but formed only a protective layer of silicon-containing amorphous carbon (including hydrogen). The silicon-containing amorphous carbon (including hydrogen) layer is
Since it has adhesiveness by itself, it becomes a protective film having sufficient adhesive strength without an adhesive layer. Table 1 shows the thickness and the formation method of the protective layer. The total thickness of the protective film, which is the sum of the thickness of the adhesive layer and the thickness of the protective layer, is 2.5 n for Nos.
m, 1.8 nm, 9.0 nm, 4.4 nm, 5.0 n
m, 4.3 nm and 2.0 nm. Although the thickness of the adhesive layer and the protective layer of the protective film is about 2 nm or less, it is considered that the film is not actually a continuous film. However, in this embodiment, the film thickness is determined by spectral ellipsometry (JOBIN YVON). Company)
In this case, since the film thickness is measured optically, the film thickness is expressed here.

[0050]

[Table 1]

As shown in Table 1, the protective layers No. 1 to No. 7 were formed on samples having different surface roughnesses of the magnetic film 11 on the air bearing surface formed by polishing with the above-mentioned surface plate.

Finally, on the surface of the bar 102 which will be the floating surface,
The rail 103 is formed in consideration of the flying characteristics (FIG.
(D)). Finally, the bar 102 is cut into chips to complete the magnetic head 1 (FIG. 3E).

By such a process, the magnetic film 1 on the air bearing surface is formed.
Magnetic head samples having a surface roughness of 1 and a material and thickness of the protective film different from each other were prepared for each 300 conditions in Table 1. The surface roughness in Table 1 is the average of the surface roughness (Rmax) of 300 samples.

In order to investigate the relationship between the surface roughness of the air bearing surface of these magnetic head samples, the thickness of the protective film, and the corrosiveness,
A corrosion test was performed. The evaluation of corrosiveness was conducted at a temperature of about 30 ° C.
Leaving the magnetic head sample in a corrosive gas such as SO ₂ , H ₂ S, NO _x or the like at a humidity of about 85% for 20 hours accelerates the corrosion and causes corrosion on the magnetic film 11 and the upper shield film 12. It was performed by observing with an optical microscope whether or not it was performed. If the magnetic film 11 and the upper shield film 12 were corroded, it was determined that the MR element made of a material more corrosive than the magnetic film 11 and the upper shield film 12 was also corroded. Table 1 shows the ratio of the magnetic head sample in which corrosion occurred among the 300 magnetic head samples prepared for each condition as the corrosion occurrence rate. FIG. 14 shows the relationship between the corrosion occurrence rate, the surface roughness of the magnetic film 11 on the air bearing surface, and the thickness of the protective film 104.

As a result, the surface roughness of the magnetic film 11 becomes Rm
It was found that when ax was 2.0 nm or less, the rate of occurrence of corrosion tended to rapidly decrease regardless of the material of the protective film 104. That is, the surface roughness of the magnetic film 11 is Rm
It was found that when ax was set to 2.0 nm or less, the corrosion occurrence rate could be reduced to almost 0 even with a film thickness of 7.0 nm or less which could not be realized conventionally due to the occurrence of corrosion. As shown in FIG. 10, the reason why the occurrence of corrosion sharply decreases at a surface roughness of 2 nm is as shown in FIG.
This is considered to be related to the fact that the floating surface no longer scratches. It is considered that by eliminating the occurrence of scratches, the floating surface can be uniformly covered even with the thin protective film 104 (FIG. 1B), so that the corrosion resistance can be improved. When the thickness of the protective film 104 is less than 2.0 nm, the surface roughness of the magnetic film becomes 2.0n.
The phenomenon that the rate of occurrence of corrosion rapidly decreases at m is no longer observed, so the thickness of the protective film 104 needs to be 2.0 nm or more. This is because the film thickness is 2.
If the thickness is smaller than 0 nm, the film is not a continuous film but an island-like film, which is presumed to be due to a decrease in coating characteristics.

As described above, by setting the surface roughness of the magnetic film on the air bearing surface of the magnetic head to Rmax 2.0 nm or less, corrosion can be prevented even when the thickness of the protective film 104 is 7 nm or less. I understand. Also, at least 2n
m can be reduced.

Since the surface roughness of 2 nm substantially corresponds to the abrasive grain size of 1/10 μm as shown in FIG. 10, abrasive grains having a grain size of about 1/10 μm or less are fixed to the polishing of the floating surface. By using the fixed surface plate, the thickness of the protective film 104 becomes 7
It is possible to manufacture a magnetic head having an nm or less and an MR element having excellent corrosion resistance.

Further, these magnetic head samples were mounted on a magnetic disk device and evaluated for durability.
Even after 30,000 times of ntact start stop, no abrasion of the protective film on the air bearing surface was observed and the condition was good.

The material of the protective film 104 includes hydrogen-containing amorphous carbon, silicon-containing amorphous carbon, nitrogen-containing amorphous carbon, and fluorine-containing amorphous carbon used in the above embodiment. Although preferred, other materials can be used. The protective film can be formed using a sputtering method or a CVD method.
In terms of coating performance, the CVD method is more preferable than the sputtering method. In the CVD method, Capacitively-Co
coupled-Plasma (CCP) -CVD method, I
nductively-Coupled-Plasma
(ICP) -CVD method, Electron-Cyclo
tron-Resonance (ECR) -CVD method,
There is an ion plating (IP) method or the like, and an appropriate method can be used from these methods.

When hydrogen-containing amorphous carbon is used, hydrocarbon-based raw materials such as methane, ethane, ethylene, benzene, and toluene, and alcohol-based raw materials such as methanol and ethanol are used as raw materials. At this time, the electric resistivity, the film stress and the like can be optimized by controlling the film forming conditions by using any of the above film forming methods. In particular, the hydrogen concentration in the film is an important parameter that affects the electrical resistivity, hardness, and combustion resistance.If the hydrogen concentration is too low, the insulating property decreases,
On the other hand, if the hardness is too high, the film hardness decreases.
A range of 0 atm% is preferred. Among them, preferably 2
0 to 40 atm%.

When silicon-containing amorphous carbon is used, it can be formed by using a mixture of a hydrocarbon gas and a gas such as silane (SiH ₄ ) or disilane (Si ₂ H ₆ ) as a raw material gas. The electrical resistivity and the film strength can be controlled by the silicon content, but this can be realized by changing the flow ratio of each gas under the film forming conditions. If the amount of silicon is too large, the insulating property is reduced, and if the amount is too small, the strength of the film tends to be reduced. Therefore, the silicon content in the formed film is 10 to 10.
70 atm% is preferred. Among them, preferably 20 to 6
0 atm%.

When nitrogen-containing amorphous carbon is used, it can be formed by using a mixture of a hydrocarbon gas and a nitrogen gas as a raw material gas. If the film contains too much nitrogen, the strength of the film tends to decrease. Therefore, the nitrogen content is preferably in the range of 0 to 50 atm% by appropriately selecting the film forming conditions.

Similarly, when using fluorine-containing amorphous carbon,
It can be formed by mixing carbon tetrafluoride with a hydrocarbon-based gas. Also in this case, when the content of fluorine increases, the film strength tends to be remarkably reduced. Therefore, a preferable fluorine content is selected from the range of 0 to 10%.

Among these materials, since silicon-containing amorphous carbon has adhesiveness itself, it can be applied as a single-layer film like the protective film No. 7 in Table 1 of the above embodiment. For other materials, No. 1 to No. 6 in Table 1
An adhesive layer is formed as in the protective layer. As the adhesive layer,
In addition to amorphous silicon, amorphous silicon oxide, amorphous silicon carbide, or the like can be preferably used. These films are formed by a sputtering method or a CVD method. The film thickness is desirably as thin as possible from the viewpoint of reducing the thickness of the protective film. However, if the film thickness is smaller than 0.5 nm, the adhesive strength (scratch strength) sharply decreases as shown in FIG. 5 nm
It is necessary to make the film thickness more than the above. FIG. 13 shows an amorphous silicon layer as an adhesive layer on an alumina titanium carbide substrate in order to examine the relationship between the adhesive strength and the film thickness of the adhesive layer.
A sample in which an amorphous carbon layer was formed as a protective layer was prepared, and the sample was pressed against the sample using a scratch tester (Reska Co., Ltd. ultra-thin scratch tester CSR-02) while vibrating the indenter and bonding the sample. Load of the indenter (scratch strength) when the layer and protective layer are destroyed and the substrate surface is exposed
Is measured, and it is graphed. In the samples, the thickness of the protective layer was 8 nm, and the thickness of the adhesive layer was variously different as shown on the horizontal axis in FIG. The measurement conditions were as follows: indenter tip diameter: 5 μm, stage angle: 8 degrees, stage feed: 5 μm / s, indenter amplitude: 80 μm, indenter frequency: 30H
z.

As described above with reference to FIG. 10, the air bearing surface is polished using a surface plate having an abrasive grain size of 1/10 μm or less, and the surface roughness of the magnetic film 11 is reduced to 2 nm or less. The occurrence of scratches on the air bearing surface can be prevented. By preventing the occurrence of scratches as described above, it is possible to prevent a phenomenon in which the upper and lower shield films 12 and 13 are electrically short-circuited, which is conventionally caused by scratches across the MR element 14. Therefore, the surface roughness of the magnetic film 11 is set to 2n as in the present embodiment.
By setting m or less, corrosion of the MR element 14 can be prevented, and electrical shorting of the MR element can be prevented at the same time.

Further, by using a surface plate on which the abrasive grains produced by the method of this embodiment are fixed and a water-insoluble solvent for polishing the air bearing surface, the processing step can be reduced to 2 nm or less as shown in FIG. Therefore, the floating surface can be sufficiently protected by the thin protective film 104 having a thickness of 7 nm or less even at the processing step portion.

As the water-insoluble lubricant used for polishing, a hydrocarbon solvent is particularly suitable. As the hydrocarbon-based solvent, a paraffinic mineral oil, a naphthenic mineral oil, or the like can be used. Specifically, OS oil manufactured by Nippon Engis (Kinematic viscosity: 2.9 cSt, 20 ° C), Showa Denko D
OSL oil (kinematic viscosity 4.6cSt, 20 ° C), Cosmos Chemical clear solution (kinematic viscosity 3.9cSt, 20
° C) can be suitably used. The viscosity of the water-insoluble lubricant is preferably not more than 5.0 cSt at 20 ° C. in consideration of the polishing efficiency.

As described above, as in the present embodiment, the surface roughness (Rm
By reducing ax) to 2.0 nm or less, a thin-film magnetic head that satisfies the corrosion resistance of the MR element even when the thickness of the protective film is reduced to the range of 2.0 nm to 7.0 nm. Can be provided. At the same time, since the processing step can be reduced to 2 nm or less, the performance of covering the protective film at the processing step does not decrease, and the occurrence of corrosion at the processing step can be prevented. Therefore, the protective film is
Since the flying height of the head can be significantly reduced by both being able to be as thin as below and the processing step being able to be made 2 nm or less, it is possible to achieve both improvement in recording density and maintenance of reliability.

[0069]

As described in detail above, according to the present invention, M
It is possible to provide a thin-film magnetic head capable of preventing corrosion of the R element and reducing the thickness of the protective film.

[Brief description of the drawings]

FIG. 1A is an explanatory view showing a state in which a protective film 104 is formed on a thin film magnetic transducer 2 having a rough surface, and FIG. 1B is a view showing a protective film on the thin film magnetic transducer 2 having a small surface roughness. 104
FIG. 4 is an explanatory view showing a state in which is formed.

FIG. 2 is an explanatory diagram showing a schematic configuration of a magnetic head 1 and a magnetic disk device using the same.

FIGS. 3A to 3E are perspective views showing manufacturing steps of a magnetic head.

FIG. 4 is an explanatory view showing a method of performing polishing using a lapping liquid in which diamond abrasive grains are dispersed.

FIG. 5 shows the configuration of the magnetic head 1 and the magnetic head 1
FIG. 3 is an explanatory view showing a positional relationship between the magnetic disk and the magnetic disk 5;

FIG. 6 is an explanatory diagram showing a state of a scratch generated on a floating surface of a magnetic head.

FIGS. 7A and 7B are explanatory views showing the action of abrasive grains on a magnetic head which is a body to be polished when a conventional lapping liquid is used and when the fixed abrasive grains according to the present embodiment are used; .

FIG. 8 is an explanatory view showing a method of processing the surface of the surface plate used for polishing the air bearing surface of the magnetic head in the embodiment.

FIGS. 9A and 9B are explanatory views showing a method of cleaning a surface plate in which abrasive grains are embedded in the present embodiment with a solvent of a polishing liquid.

FIG. 10 is a graph showing the relationship between the roughness of the upper magnetic film of the magnetic head polished with the surface plate manufactured by the method of the present embodiment and the abrasive grain size of the surface plate.

FIG. 11 is a view showing an upper magnetic film 11 and an upper shield film when a water-soluble lubricant is used to polish the floating surface of the magnetic head 1 with a surface plate on which abrasive grains are fixed in the present embodiment. Sectional drawing of the magnetic head 1 for showing the phenomenon that 12 protrudes.

FIG. 12 is a graph showing, for each lubricant, a relationship between a processing step on the air bearing surface of the magnetic head 1 polished with a surface plate on which abrasive grains are fixed and an abrasive system in the present embodiment.

FIG. 13 is a graph showing the relationship between the thickness of the adhesive layer and the adhesive strength of the protective film when the protective film of the magnetic head of the present embodiment has a two-layer structure of an adhesive layer and a protective layer.

FIG. 14 is a graph showing the result of examining the relationship between the surface roughness of the air bearing surface and the corrosion occurrence rate by changing the thickness of the protective film in the magnetic head of the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic head, 2 ... Thin film magnetic transducer, 3 ...
..Floating surface, 4 ... Support spring, 5 ... Magnetic disk, 6 ... Driver, 7 ... Floating amount, 8 ... Processing step, 9 ... Recording inductive element, 10a, 10b ...
· Upper and lower protective layers, 11: Upper magnetic film, 12
... upper shield film, 13 ... lower shield film, 1
4 ... MR element for reproduction (magnetoresistive effect) element, 15 ...
Surface plate, 16: lapping liquid, 17: polishing jig, 20
... Fixed abrasive grain, 21 ... Scratch, 22 ... Cutting amount, 23 ... Diamond bite, 24 ...
Abrasive grains with low support rigidity, 25 ... solvent, 101 ... substrate, 102 ... bar, 103 ... rail, 104
..Protective film on air bearing surface, 105 ... insulating film, 115
・ Surface plate, 119: rolling abrasive grains, 1101: lapping machine.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroshi Inaba 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi, Ltd. Production Engineering Laboratory (72) Inventor Toshio Tamura 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Shares Yoshiharu Waki, Hitachi, Ltd. (72) Inventor Yoshiharu Waki 2880 Kozu, Odawara-shi, Kanagawa Prefecture Hitachi, Ltd. Storage Systems Division (56) References JP-A-7-299737 (JP, A) JP-A Sho 62 -292358 (JP, A) JP-A-8-297813 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/31 G11B 5/39 G11B 5/60 G11B 21/21 101

Claims (12)

(57) [Claims] An end face of said substrate and said thin film magnetic conversion element which constitutes a floating surface facing a magnetic recording medium, wherein said thin film magnetic conversion element is mounted on said substrate; The magnetic transducer has one or more magnetic films, and the surface roughness of the air bearing surface is at an end surface of the magnetic film.
A thin film magnetic head having a Rmax of 2 nm or less, and a protective film having a thickness of 7 nm or less disposed on the air bearing surface. 2. The thin-film magnetic head according to claim 1, wherein said thin-film magnetic transducer has an inductive magnetic transducer and a magneto-resistive magnetic transducer. . 3. The thin-film magnetic head according to claim 1, wherein the surface roughness of the air bearing surface at the end face of the magnetic film is set at a scanning distance of 10 μm using a probe having a tip diameter of 10 nm.
A thin-film magnetic head characterized in that it is measured by an atomic force microscope. 4. The thin-film magnetic head according to claim 1, wherein said protective film has a thickness of 2 nm or more. 5. The thin-film magnetic head according to claim 1, wherein the protective film includes an adhesive layer disposed on the air bearing surface, and a protective layer disposed on the adhesive layer. The thin film magnetic head according to claim 1, wherein said adhesive layer has a thickness of 0.5 nm or more. 6. The thin-film magnetic head according to claim 5, wherein said adhesive layer is formed of any one of amorphous silicon, amorphous silicon oxide, and amorphous silicon carbide. A thin film magnetic head characterized by the above-mentioned. 7. The thin-film magnetic head according to claim 1, wherein said protective film comprises at least one layer, and said at least one layer includes hydrogen-containing amorphous carbon, silicon-containing amorphous carbon, and silicon-containing amorphous carbon. A thin-film magnetic head comprising a layer made of any one of nitrogen amorphous carbon and fluorine-containing amorphous carbon. 8. The thin-film magnetic head according to claim 1, wherein the floating surface is formed by a step of polishing using a surface plate fixed by embedding abrasive grains having a particle size of 1/10 μm or less. A thin film magnetic head characterized by the above-mentioned. 9. The thin film magnetic head according to claim 8, wherein a water-insoluble lubricant is used in the polishing step. 10. The thin-film magnetic head according to claim 8, wherein a processing step of said thin-film magnetic conversion element on said air bearing surface formed by said polishing step is 2 nm or less. head. 11. A thin-film magnetic head comprising: a rotation drive device for rotating a magnetic disk; and a thin-film magnetic head, wherein the thin-film magnetic head has a substrate and a thin-film magnetic transducer mounted on the substrate. And an end surface of the thin-film magnetic transducer constitutes an air bearing surface facing a magnetic recording medium; the thin-film magnetic transducer has one or more magnetic films; and a surface roughness of the air bearing surface is the magnetic film. At the end face of
Rmax is 2 nm or less, and a protective film having a thickness of 7 nm or less is disposed on the air bearing surface. 12. A first step of processing the surface of the surface plate into a shape corresponding to the air bearing surface of the thin film magnetic head to be manufactured, and an elastic surface holding abrasive grains for smoothing the surface of the surface plate. A second step of polishing the surface of the surface plate with a member; supplying abrasive particles having a particle size of 1/10 μm or less and a solvent to be embedded in the surface of the surface plate; A third step of embedding the abrasive grains having a particle size of 1/10 μm or less in the surface of the surface plate by pressing against the surface of the surface plate; A fourth step of processing the surface roughness to an Rmax of 2 nm or less on the end face of the magnetic film included in the thin-film magnetic head; A thin film magnetic Manufacturing method of de.