JPH04360017A - Metallic thin film type magnetic disk and production thereof - Google Patents

Abstract

PURPOSE:To satisfy the various characteristics required for a carbon film for protecting a magnetic metallic film in the magnetic disk formed by protecting the magnetic metallic film with the carbon film. CONSTITUTION:The carbon film 6 on the magnetic metallic film 5 is formed as a soft film type on a front surface side 62 and as a hard film type on the magnetic metallic film 5 side 61. The texture grooves which are shallowest to the min. required limit for impartation of magnetic anisotropy are formed on the magnetic metallic film 5 and the surface of the carbon film is subjected to a surface roughening treatment in order to prevent the attraction of a magnetic head and to decrease the coefft. of friction. A lubricant is applied thereon. Boron is incorporated into the carbon protective film 6. He is used as a sputtering gas for the carbon film. The carbon film is heat treated in a reducing gaseous atmosphere after the sputtering of the carbon film, by which the oxygen in the carbon film is removed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal thin film type magnetic disk used as a recording medium in a magnetic disk drive, which is an external storage device for a computer system, and a method for manufacturing the same.

In recent years, metal thin film type magnetic disks, in which a magnetic film is formed by forming a metal thin film using techniques such as sputtering or plating, have become mainstream as high-density recording magnetic disks. Metal thin-film magnetic disks are produced by forming microscopic grooves in the circumferential direction on a non-magnetic disk using a method called texturing, then sputtering a metal magnetic film and a protective film, and applying a lubricant on top of that. Generally, a carbon film is used as the protective film.

0003

2. Description of the Related Art FIG. 12 is a cross-sectional view showing a conventional method for manufacturing a metal thin film magnetic disk in order of steps. 1 is a donut-shaped substrate made of a non-magnetic material such as aluminum, and on the NiP plating base layer 2 formed thereon, in step (1), polishing is applied to the surface of the rotating non-magnetic substrate. By pressing the tape, fine textured grooves 3 are formed in the circumferential direction. Note that it has also been proposed to form texture grooves by transfer using a stamper or by laser beam processing.

[0004] In step (2), the texture groove 3
A Cr layer 4 is formed on top of the Cr layer 4 to improve the bonding property, and a metal magnetic film 5 made of a Co alloy or the like is formed thereon in step (3). As shown in step (4),
A carbon film 6 is formed as a protective film on the metal magnetic film 5, and finally a Fomblin-based lubricant 7 is applied. Cr
Layer 4, Co alloy magnetic film 5, and carbon film 6 are formed by a method such as sputtering.

Textured groove 3 formed in step (1)
This is to impart magnetic anisotropy to the metal magnetic film 5 to improve magnetic recording/reproducing characteristics. Also,
Since the carbon film 6 also becomes uneven along the textured grooves 3, the magnetic head is less likely to be attracted to the magnetic disk surface, and the friction between the magnetic head and the magnetic disk surface is reduced.

[0006]

As described above, the protective layer 6 made of a carbon film is most susceptible to the effects of sliding with the magnetic head, and as a result, the metal magnetic film 5 is also likely to be affected. In other words, if the film strength of the carbon protective film is weak, the protective function of the underlying metal magnetic film will deteriorate, and if the magnetic head has poor sliding properties or the magnetic head is easily attracted, the carbon protective film will be easily damaged. Become.

By the way, the conventional carbon film 6 is made of graphite carbon (hereinafter referred to as "
G carbon) and diamond-like carbon (hereinafter abbreviated as D carbon), which is hard and has poor sliding properties, are mixed. Therefore, although it cannot be said that the sliding properties and wear resistance of the magnetic head are particularly bad, they cannot be said to be particularly good either, and the magnetic head's CSS (Contact Start Stop
) During repeated operations, the coefficient of friction increases, and sliding marks are generated on the carbon film surface, resulting in a shortened service life.

However, as high-density recording on magnetic disks is required in recent years, the flying height of the magnetic head has become smaller and smaller, and the probability of contact with the magnetic disk surface has increased. Therefore, more than ever before, there is a demand for a magnetic disk that has both magnetic head sliding properties and wear resistance, and for this purpose the role of the carbon film has become extremely important.

[0009] In addition, in conjunction with the original function of the carbon film,
The unevenness of the carbon film surface, which is the effect of texture processing,
This is important in preventing adhesion of the magnetic head and an increase in the coefficient of friction.

The technical problem of the present invention is to address these problems and to provide a magnetic disk in which a metal magnetic film is protected by a carbon film, in which the adsorption force of the magnetic head is weak and the sliding property is excellent. , strong film strength to protect the underlying metal magnetic film, ability to retain lubricant for a long period of time, error-free recording/reproduction on the metal magnetic film, and magnetic properties of the metal magnetic film. The objective is to satisfy various characteristics required of a carbon film for protecting a metal magnetic film, such as not impairing the properties of the carbon film.

[0011]

[Means for Solving the Problems] FIG. 1 is a sectional view illustrating the basic principle of a metal magnetic disk and a method of manufacturing the same according to the present invention. 5 is a metal magnetic film, 6 is a carbon film,
7 is a lubricant. Unlike coating-type magnetic disks, metal thin-film type magnetic disks cannot be impregnated with lubricant and cannot maintain a lubricating effect for a long period of time.
As described in , the surface of the carbon film 6 itself is made a soft film so as to exhibit a lubricating effect, and the metal magnetic film 5 side is made a hard film so as to protect the metal magnetic film 5. Therefore, the carbon film 6 does not have uniform film quality throughout, but has a structure in which the metal magnetic film 5 side is hard and the surface side is soft.

Furthermore, even without changing the film quality of the carbon film 6 between the metal magnetic film 5 side and the surface side, the lubricating action of the lubricant 7 can be maintained, and the sliding properties of the magnetic head can be ensured. If so, it is better for the carbon film 6 to be hard as a whole and have strong film strength. For this purpose, in claim 2, the surface of the carbon film 6 is roughened to form fine irregularities, and a lubricant is applied thereon, in order to maintain the lubricating effect on the surface of the carbon film 6. The structure is as follows.

On the other hand, if moisture is attached to the surface of the carbon film 6, the lubricant and the carbon film 6 will be mixed together when the lubricant is applied.
However, if the lubricant is applied after drying the carbon film surface by high-frequency heating as in claim 3, the affinity will be improved and the life of the lubricant will be extended.

According to a fourth aspect of the present invention, in order to form a highly hard carbon film with few defects, an inert gas having an atomic weight smaller than Ar is used as a sputtering gas.

If oxygen is mixed into the carbon film, it will cause defects and reduce the film strength. Remove oxygen from the film.

[0016] The carbon film becomes diamond-like,
When the film becomes hard, its electrical conductivity is low, and the element part of the thin-film magnetic head may be discharged and destroyed due to charging.
Although dust is easily attracted to the carbon film, if boron is mixed into the carbon film as described in claim 6, the electrical conductivity is improved and it becomes difficult to be charged.

[0017]

[Operation] In the thin-film type magnetic disk on which the metal magnetic film 5 is formed, the carbon film 6 formed on the metal magnetic film 5 has a soft film quality on the surface side 62. The metal magnetic film 5 side 61 has a hard film quality. Therefore, even if the lubricant is consumed and the lubricating effect is reduced, the surface side 62 of the carbon film 6 is soft, so when the magnetic head makes sliding contact, no impact will be generated on the magnetic head or magnetic disk side. damage to both sides can be prevented.

Moreover, since the metal magnetic film 5 side of the carbon film 6 is hard, even if the soft surface side 62 is damaged,
Since the hard carbon layer 61 is present thereunder, the metal magnetic film 5 can be prevented from being damaged.

As claimed in claim 2, the texture treatment on the underside of the metal magnetic film 5 is a shallow texture groove that is the minimum necessary for imparting magnetic anisotropy to the metal magnetic film. On the surface of the carbon film 6 on the
The surface has been roughened to prevent the magnetic head from adhering and to reduce the coefficient of friction, so all of the objectives of the texture treatment are met.Moreover, the texture grooves formed under the metal magnetic film are extremely shallow, so no abnormalities can occur. This can prevent errors from occurring due to scratches. Since the lubricant is applied to the roughened surface of the carbon film 6, the lubricant accumulates in the depressions of the rough surface and gradually oozes out to the convex parts and is supplied. is maintained over a long period of time, extending the life of the lubricant.

By roughening the surface of the carbon film 6 and applying a lubricant thereon, the life of the lubricant is extended and the sliding properties of the magnetic head are ensured. 3
As described in , by applying a lubricant after drying the carbon film surface by high-frequency heating, the affinity between the carbon film 6 and the lubricant is improved, and the life of the lubricant is further extended. In particular, since only the moisture is heated and evaporated by high-frequency heating, the magnetic properties of the metal magnetic film 5 do not deteriorate.

Furthermore, as described in claim 4, since the carbon film is formed by sputtering using an inert gas with an atomic weight smaller than Ar as a sputtering gas, when a conventional sputtering gas with a large atomic weight such as Ar is used. Compared to
A highly hard carbon film with few defects can be formed.

As described in claim 5, after sputtering the carbon film, heat treatment is performed in a reducing gas atmosphere to remove oxygen in the carbon film, thereby reducing the amount of oxygen in the carbon film. Defects caused by oxygen are eliminated,
Membrane strength is improved.

[0023] When the film strength of the carbon film is improved in this way, the carbon film becomes diamond-like and the film quality becomes hard. As a result, the electrical conductivity is low, and the element part of the thin film magnetic head is easily damaged by discharge due to charging, and dust is easily attracted. However, when boron is mixed into the carbon film as described in claim 6, Improves electrical conductivity and becomes less likely to be charged. This prevents discharge damage to the element portion of the thin-film magnetic head, reduces the amount of dust attached, and prevents head crashes.

[0024]

EXAMPLES Next, examples will be used to explain how the metal thin film type magnetic disk and the manufacturing method thereof according to the present invention are actually implemented.

[Embodiment of the invention according to claim 1] FIG. 2 is a sectional view showing an embodiment of the metal thin film type magnetic disk according to claim 1. In the carbon film 6, the surface side 62 is a soft G carbon film, and the metal magnetic film 5 side 61 is a hard D carbon film.

In this way, the carbon film 6 can be made hard on the metal magnetic film 5 side and soft on the surface side by a combination of sputtering temperature, sputtering power, and target pair. In the embodiment, sputtering is performed at a low temperature when forming the carbon film 61 on the metal magnetic film 5 side, and sputtering is performed at a high temperature when forming the carbon film 62 on the front side, so that the carbon film 62 on the front side is soft. The carbon film 61 on the metal magnetic film 5 side was made hard. The total thickness of the metal magnetic film 5 side and the surface side is 200~
The thickness was about 500 Å. Note that by continuously changing the sputtering conditions, the film hardness can also be changed continuously.

FIG. 3 shows the Raman spectra of carbon films, where (a) shows conventional G carbon and D carbon films.
A carbon film in which carbon is mixed, (b) is a carbon film on the metal magnetic film 5 side in the present invention, and (c) is a carbon film on the front side in the present invention.

As is clear from the Raman spectroscopy spectrum shown in (b), the carbon film 61 on the metal magnetic film 5 side has a pattern of diamond-like carbon, and it is clear from the Raman spectroscopy spectrum shown in (c). As shown, the carbon film 62 on the front side has a typical glassy carbon pattern. On the other hand, (a
) As shown in (b) and (c), the conventional carbon film is
), and it is recognized that D carbon and G carbon coexist.

FIG. 4 is a diagram comparing the coefficient of friction between a conventional magnetic disk and a magnetic disk according to an embodiment of the present invention when the magnetic head slider is slid at 100 rpm. In the magnetic disk with the conventional carbon film shown in (a), the coefficient of friction after 60 minutes exceeds 0.4.
Furthermore, while the friction coefficient is constantly changing, in the embodiment of the present invention, as shown in Figure (b), the friction coefficient did not reach 0.4 even after 60 minutes, and fluctuations in the friction coefficient did not occur. Not yet.

[0030] Also, after 60 minutes of sliding in this way, 1rp
As a result of measuring the coefficient of static friction at m, the coefficient of static friction was approximately 0.3 for conventional magnetic disks and constantly fluctuating, whereas it was approximately 0.1 to 0.2 for the embodiment of the present invention, and the coefficient of friction was approximately 0.3. There was also very little variation.

As is clear from the experimental results, by using soft G carbon as the carbon film 62 on the surface side, the frictional characteristics are improved, and since it is soft, the impact resistance is also improved. Even if the soft G carbon film 62 is destroyed, since the hard D carbon film 61 is present underneath, the progression of wear is suppressed and destruction of the metal magnetic film 5 is more reliably prevented. Ru. As a result, stable magnetic recording/reproduction is possible with excellent sliding properties, and the life of the magnetic disk is extended due to improved wear resistance.

[Embodiment of the invention according to claim 2] FIG. 5 is a sectional view showing an embodiment of the invention according to claim 2. Metal magnetic film 5
Before forming the textured grooves 8, the textured grooves 8 are formed using a lapping tape with fine abrasive grains, and are made as shallow as necessary to impart magnetic anisotropy to the metal magnetic film 5. The surface 9 of the carbon film 6 is roughened to prevent adsorption of the magnetic head and to reduce the coefficient of friction, and a lubricant 7 is applied thereon.

The purpose of the texture treatment is to impart magnetic anisotropy to improve the magnetic recording/reproducing characteristics of the metal magnetic film, to prevent the magnetic head from being attracted to the magnetic disk surface, and to prevent the magnetic head from being attracted to the magnetic disk surface. The objective is to reduce the coefficient of friction between the magnetic disk and the magnetic disk. Conventionally, as shown in FIG. 12, texture processing is performed before forming the metal magnetic film 5, but when forming the textured grooves, abnormal scratches occur in the depth direction of the grooves, making it difficult to record/record information. This causes an error during playback.

In contrast, in the present invention, the textured grooves 8 formed before forming the metal magnetic film 5 are the minimum shallow grooves necessary to impart magnetic anisotropy to the metal magnetic film 5. Unlike conventional methods, abnormally deep scratches do not occur in the groove direction, and there is no risk of causing errors when recording/reproducing information. As a result, the core width of the magnetic head is narrowed, making it extremely effective for magnetic disks that perform high-density recording.

The conventional texture grooves formed before forming the metal magnetic film 5 have an Ra (center average line roughness) of 1.
00 Å, but in the case of the present invention, Ra40-50
About Å is sufficient. According to the experimental results, the diameter is 5.25
A shallow textured groove was formed on a NiP substrate of inch size using wrapping tape of WA #8000, and a Cr
Film, metal magnetic film made of Co-based alloy, film thickness 500 Å
A carbon protective film is formed on the surface of this carbon film.
When textured grooves with an Ra of 70 Å were formed using A#4000 wrapping tape, only 6 missing errors occurred.

[0036] Ra100 is applied only under the conventional metal magnetic film.
In the case of a magnetic disk that has been textured with Å,
Compared to the 30 missing errors that occurred, the number of errors has been reduced to one-fifth, which proves that abnormal texture processing flaws have been significantly reduced.

On the other hand, since the surface 9 of the carbon film 6 has been roughened, the magnetic head is less likely to be attracted to it, and an increase in the coefficient of friction is suppressed. As shown in FIG. 12, a textured groove is formed before forming a metal magnetic film 5, and by laminating a Cr layer 4, a metal magnetic film 5, and a carbon film 6 thereon, the textured groove is gradually flattened. However, since the present invention directly roughens the surface of the carbon film 6 with which the magnetic head comes into contact, it is easy to obtain the desired surface roughness, and the surface is surely roughened and the magnetic head is can guarantee prevention of adsorption and reduction of friction coefficient.

Moreover, it is sufficient that the roughened portion 9 on the surface of the carbon film is shallow. In addition, unlike the gently curved surface of conventional carbon film surfaces, it has a fine triangular wave shape, which is highly effective in preventing magnetic head adsorption and reducing the coefficient of friction, which is required for high-density recording. It can also meet requests for levitation. The retention of the lubricant 7 is also improved, which can contribute to extending the life of the magnetic disk.

It should be noted that the roughening treatment on the surface of the carbon film 6 can be carried out by using a lapping tape in the same manner as in conventional texturing. However, unlike the texture treatment on the underside of the metal magnetic film 5, Since the purpose is not to achieve magnetic anisotropy, the grooves do not necessarily have to be circumferential.

[Embodiment of the invention of claim 3] The invention of claim 3 dries the surface of the carbon film by high-frequency heating using microwaves, and then applies a lubricant to the carbon film 6 to lubricate it. This method improves the affinity with the drug.

Since moisture in the air is attached to the surface of the carbon film 6, even if a lubricant is applied thereon, the affinity between the lubricant and the carbon film is poor, and the lubricant is not applied to the carbon film. It cannot be attached reliably and stably. Furthermore, when the lubricant mixes with water, the quality of the lubricant changes and its lubricating effect decreases.

Conventionally, after forming a carbon film, the magnetic disk is heated in a furnace to evaporate water on the surface of the carbon film, and then a lubricant is applied. However, this heat treatment causes a problem in that the film quality of the carbon film changes and wear resistance decreases.

On the other hand, as in the present invention, when the magnetic disk before the lubricant is applied is subjected to high-frequency heating using microwaves to dry the surface of the carbon film, only the moisture is heated, and the carbon film is not heated. Not done. As a result, problems such as deterioration of the quality of the carbon film and deterioration of wear resistance do not occur.

FIG. 6 is a diagram showing the quality of the carbon film based on a Raman spectroscopic analysis spectrum. (a) (b) are diagrams showing the carbon film quality before and after heating by the conventional method, (c) (d)
FIG. 2 is a diagram showing the carbon film quality before and after high-frequency heating according to the method of the present invention. While the Raman spectra before heating have the same pattern as shown in (a) and (c), the Raman spectra after heating differ as shown in (b) and (d).

[0045] In other words, in the carbon film heated by the conventional method, a new peak appears as shown at 10 in (b), and this second peak occurs because of G carbon. It can be seen that the film quality is softened. On the other hand, in the carbon film heated by the method of the present invention, as shown in (d), no new peaks were generated, and the Raman spectrometry spectrum was almost different from the Raman spectrometry spectrum shown in (c) before heating. Not yet. Thus, while the conventional heating method softens the carbon film quality, the high frequency heating method of the present invention does not change the film quality.

FIG. 7 shows the results of measuring the abrasion resistance before and after heat treatment by pressing and sliding a wrapping tape on a magnetic disk heated by the conventional method and a magnetic disk heated with high frequency by the method of the present invention. . As shown in (a), in the magnetic disk heated by the conventional method, the wear depth of the carbon film after heating is extremely deeper than before heating, whereas the magnetic disk heated by the method of the present invention has , only slightly deeper. Although it is small in this way,
The deeper wear depth is thought to be due to the effect of temperature rise due to conduction heat generated when water on the surface of the carbon film generates heat.

As described above, according to the moisture removal method using high-frequency heating of the present invention, the moisture on the surface of the carbon film is removed without softening the quality of the carbon film, and then the lubricant is applied, so that the carbon film does not change in quality. By improving the bonding force between the Zukatsu lubricant and the carbon film, it becomes possible to extend the life of the magnetic disk.

[Embodiment of the invention of claim 4] Claims 4 and 5
The purpose is to improve the hardness of the carbon film, and for this purpose, the invention according to claim 4 uses He, which has a small atomic weight, as a sputtering gas when forming the carbon film by sputtering. Conventionally, when forming a carbon film by sputtering,
Although Ar is used as the sputtering gas, it is inevitable that the sputtering gas Ar will mix into the carbon film during sputtering film formation.

[0049] When Ar is mixed in the carbon film as described above, the foreign material Ar becomes a defect and causes a decrease in the strength of the carbon film. Moreover, since Ar has a large atomic weight, it easily mixes into the carbon film and causes large defects.

On the other hand, when He is used as a sputtering gas when forming a carbon film as in the present invention, He
has an atomic weight of 4, which is one-tenth of Ar, which has an atomic weight of 40.
Therefore, the amount of defects when He is mixed into the carbon film is also 1
It becomes 1/0. Since the atomic radius is -15 Å for He and -19 Å for Ar, the volume ratio is 1:2, and the size of the defect is halved.

[0051] Substrate temperature: 280°C, sputter power: 1
When a carbon film with a thickness of 250 Å was formed using KW and a sputtering gas pressure of 5 mTorr, the film strengths of the carbon film using Ar as the sputtering gas and the carbon film using He using the method of the present invention were measured. To measure the film strength, a wrapping tape was pressed against the rotating magnetic disk surface for a certain period of time, and the amount of abrasion of the carbon film was measured using a fluorescent X-ray film thickness meter, and the film strength was evaluated based on the amount of abrasion of the carbon film.

As a result, the carbon film sputtered using Ar had a wear amount of 50 Å, whereas the carbon film sputtered using He had a wear amount of 20 Å. That is, the carbon film formed by sputtering using He according to the method of the present invention exhibited a strength more than twice that of the carbon film formed by sputtering using Ar.

Although He was used as an inert gas having an atomic weight smaller than Ar, Ne is also effective since it also has a smaller atomic weight than Ar.

[Embodiment of the invention according to claim 5] When forming a carbon film by sputtering, Ar, which is a sputtering gas, mixes into the carbon film as described above. However, Ar
In addition to this, H (hydrogen) and O (oxygen), which are dissociated from residual moisture in the sputtering chamber, also mix into the carbon film.
This causes defects in the carbon film and causes a decrease in film strength.

[0055] Particularly highly reactive O easily bonds with carbon, so it is mixed in in a large amount, and as a result of the reaction, polyacetylene structures with weak bonding strength are mixed, resulting in a decrease in the bonding strength between carbons. As mentioned above, after the carbon film is formed, the water on the surface of the carbon film is removed by heat treatment, but before the water on the surface is removed, the water has already dissociated and O and H are released into the carbon film. It is mixed in.

In order to reduce the amount of O, it is conceivable to apply a high vacuum to remove residual moisture in the sputtering chamber, but it is extremely difficult to remove moisture adsorbed to the inner wall of the sputtering chamber. 10-7T inside the sputter chamber
Even if sputtering is performed after creating a high vacuum below orr,
The partial pressure of H2 and O2 at which adsorbed moisture is dissociated during sputtering is 10
The temperature is about −3 Torr, and it is extremely difficult to avoid mixing O into the carbon film.

[0057] Accordingly, in the present invention, as described in claim 5, after the carbon film is sputtered, it is heat-treated in an atmosphere of a reducing gas such as H2 to remove oxygen in the carbon film. . As a result, O in the carbon film reacts with the reducing gas and is removed from the carbon film. As a result, the carbon film becomes D carbon, and the film strength is improved.

Next, the film strengths of the carbon film from which O was removed by heat treatment in H2 and the carbon film from which water was removed by conventional heating were evaluated. The magnetic disk subjected to evaluation was one in which a carbon film with a thickness of 250 Å was formed using Ar as a sputtering gas at a substrate temperature of 280° C., a sputtering power of 1 kW, and a sputtering gas pressure of 5 mTorr. After the carbon film was formed, it was heat-treated in an H2 atmosphere at 280°C for 1 hour, and then the film quality was evaluated by Raman spectroscopy.

FIG. 8(a) is a Raman spectroscopy spectrum of the carbon film thus reduced by the method of the present invention. Despite being heated to 280° C., the carbon film has a diamond-like film quality because the amount of O inside the carbon film is small. On the other hand, (b) is a Raman spectroscopic analysis spectrum of a carbon film in which the moisture on the surface of the carbon film has simply been removed by heat treatment, and the second peak 10 has occurred, forming a pattern of soft G carbon. .

[0060] Also, as a result of pressing a lapping tape against the rotating magnetic disk surface for a certain period of time and measuring the amount of abrasion of the carbon film using a fluorescent X-ray film thickness meter, the carbon film that had been reduced for one hour in an H2 atmosphere showed The amount of wear was 30 Å. Compared to a conventional magnetic disk without reduction treatment, which had a carbon wear amount of 50 Å, the carbon film treated by the method of the present invention has nearly twice the strength of the conventional carbon film. There is.

[Embodiment of the invention as claimed in claim 6] As described above, the film strength of the carbon film has been improved, making it possible to extend the life of the magnetic disk. Because of the low resistance, problems such as discharge destruction of the thin-film magnetic head element section due to charging are likely to occur. In addition, it may attract dust and cause a head crash.

[0062] As a result of conducting various experiments to increase the electrical conductivity of diamond-like carbon films, it was found that adding 2 to 20% of boron (B) to the carbon film lowers the electrical resistance value. It became.

FIG. 9 is a graph showing the changes in the resistance value of the carbon film when the amount of B in the carbon target was changed. As shown in the figure, the electrical resistance value of the carbon film decreases as the amount of boron added increases, but when the amount of boron added increases
It is saturated at about 0%. That is, while the electrical resistance value of the conventional carbon film is 3 MΩ, when boron is added according to the present invention, the electrical resistance value is reduced to about 300 kΩ. Also,
When the flying height of the magnetic head was measured using an AE element, the number of times the AE element contacted the magnetic disk was reduced compared to the conventional magnetic disk in which boron was added to the carbon film according to the present invention.

FIG. 10 is a diagram comparing the magnetic head flying characteristics of a conventional magnetic disk and a magnetic disk having a carbon film doped with boron according to the present invention. This is what we sought. The horizontal axis represents the radial position of the 8-inch magnetic disk, and the vertical axis represents the flying height of the AE element.

(a) shows the flying characteristics of a conventional magnetic disk. Since the carbon film has a high electrical resistance value of 3 MΩ, a large amount of dust is attracted by charging, and the AE element easily comes into contact with the dust on the magnetic disk. As a result, the flying height at which the AE element does not come into contact with dust, etc. is 0.06 to 0.0.
08 is high.

(b) is a magnetic disk having a carbon film doped with boron according to the present invention, and has a low electrical resistance value of 300 kΩ, and because it attracts little dust due to charging, the flying height of the AE element can be reduced to 0. Even if it is as low as 0.06 to 0.04, no contact with dust or the like occurs. Therefore, the magnetic head has a very small flying height and is suitable for high-density recording magnetic disk devices.

FIG. 11 is a Raman spectroscopic analysis spectrum of a carbon film doped with boron according to the present invention, and the second peak does not appear, indicating that it is diamond-like carbon. In other words, even when boron is added, the film quality of D carbon is maintained, and even in magnetic disks with a hard D carbon film, the electrical conductivity is increased and the element destruction of thin film magnetic heads due to charging and dust absorption are prevented. Head crush can be prevented.

[0068] Although the method of adding boron to the carbon target in advance has been exemplified, it is also possible to add boron by ion implantation after forming the carbon film.

[0069]

As described above, according to the present invention, the carbon film that protects the metal magnetic film in a metal thin-film magnetic disk can provide lubrication without impairing the magnetic properties of the metal magnetic film or causing errors. It has excellent properties and can prevent the magnetic head from adhering, and has strong film strength to sufficiently protect the underlying metal magnetic film. It also has improved electrical conductivity to suppress charging and protect the metal magnetic film. It satisfies all the characteristics required of a carbon film, and is extremely effective for long-life, high-density recording magnetic disk drives.

[Brief explanation of drawings]

FIG. 1 is a sectional view illustrating the basic principle of a metal magnetic disk and its manufacturing method according to the present invention.

FIG. 2 is a sectional view showing an embodiment of the metal thin film type magnetic disk according to claim 1.

FIG. 3 shows Raman spectroscopy spectra for comparing carbon film quality; (a) is the conventional carbon film in which G carbon and D carbon are mixed; (b) is the metal magnetic film side in the present invention. (c) is the carbon film on the front side in the present invention.

FIG. 4 is a diagram comparing the coefficient of friction between a conventional magnetic disk and a magnetic disk according to an embodiment of the present invention.

FIG. 5 is a sectional view showing an embodiment of the invention according to claim 2.

FIG. 6 is a Raman spectroscopic analysis spectrum comparing the change in carbon film quality before and after heating by high-frequency heating of the conventional method and the present invention.

FIG. 7 shows the results of measuring the wear resistance before and after heating for a magnetic disk heated by a conventional method and a magnetic disk heated by high frequency heating by a method of the present invention.

FIG. 8 shows Raman spectra of a carbon film reduced by the method of the present invention and a carbon film heat-treated by the conventional method.

FIG. 9 is a graph showing the change in resistance value of the carbon film when the amount of B in the carbon target was changed.

FIG. 10 is a diagram comparing the flying height of a magnetic head between a conventional magnetic disk and a magnetic disk having a carbon film doped with boron according to the present invention.

FIG. 11 is a Raman spectroscopy spectrum of a carbon film doped with boron according to the present invention.

FIG. 12 is a cross-sectional view showing a conventional metal magnetic disk manufacturing method in order of steps.

[Explanation of symbols]

1 Non-magnetic substrate (Al substrate) 2 NiP plating layer 3 Texture groove 4 Cr layer 5 Metal magnetic film (or Co alloy) 6 Carbon film 61 Carbon film on the substrate side 62 Carbon film on the surface side 7 Lubricant

Claims (6)

[Claims] Claim 1: In a metal thin film type magnetic disk on which a metal magnetic film (5) is formed, a metal magnetic film (5) is formed.
) on the surface side (6).
2) is a soft film, and the metal magnetic film (5) side (61
) is a metal thin-film magnetic disk characterized by a hard film. 2. The texture treatment on the lower side of the metal magnetic film (5) is performed by forming a shallow texture groove that is the minimum necessary to impart magnetic anisotropy to the metal magnetic film (5). ) The surface of the upper carbon film (6) is roughened to prevent the magnetic head from adhering and to reduce the coefficient of friction, and a lubricant is applied on the surface of the metal thin film. type magnetic disk. [Claim 3] After forming the carbon film (6) on the metal magnetic film (5), drying the surface of the carbon film by high-frequency heating, and then applying a lubricant to the surface of the carbon film (6). A method for manufacturing a metal thin film magnetic disk characterized by: 4. When forming the carbon film (6) on the metal magnetic film (5) by sputtering, the sputtering is performed using an inert gas having an atomic weight smaller than Ar as the sputtering gas. A method of manufacturing a metal thin film magnetic disk. 5. A carbon film (6) is formed on the metal magnetic film (5) by sputtering, and then heat treatment is performed in a reducing gas atmosphere to remove oxygen in the carbon film (6). A method of manufacturing a metal thin film magnetic disk. 6. A metal thin film type magnetic disk characterized in that boron is mixed into a carbon protective film (6) covering a metal magnetic film (5).