JPH05174354A - Magnetic recording medium and production thereof and apparatus for producing the same - Google Patents

Abstract

PURPOSE:To obtain the recording medium which is improved in the adhesion at the boundary between a lubricating film and a protective film and has excellent durability and weatherability and the process and apparatus for production of this medium. CONSTITUTION:The recording medium formed by continuously forming a chromium film 2, a magnetic recording film 3 and the protective film 4 on a disk substrate 1 and applying the lubricating film 5 thereon is used as a sample. The sample is held in a plasma forming chamber 22 and the surface thereof is irradiated with radicals (contg. fluorine and carbon) formed by plasma CVD of fluorine and carbon tetrafluoride. As a result, a radical reaction product layer 25 is formed at the boundary between the protective film and the lubircating film. The irradiated radicals act on the boundary between the lubricating film and the protective film, by which a chemical bond is generated between the lubricant components and the surface of the protective film and the splashing resistance of the lubricating film is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, a method of manufacturing the same, and a manufacturing apparatus therefor, and more specifically, the adhesion between a protective film of the magnetic recording medium and a lubricant film coated and formed thereon. The present invention relates to a magnetic recording medium that improves (coupling force), a manufacturing method thereof, and a manufacturing apparatus thereof.

[0002]

2. Description of the Related Art For example, a magnetic recording device used as a high-speed read / write mass storage device of an electronic computer comprises a magnetic head and a rotating magnetic recording disk (hereinafter referred to as a magnetic disk). The type that contacts the surface of the magnetic disk temporarily or periodically is common. In this magnetic disk, a ferromagnetic thin film with a high recording density is formed on the surface of a non-magnetic substrate by a sputtering method, etc., and a protective film made of amorphous carbon or an inorganic compound is formed on the surface of the non-magnetic substrate. It is generally practiced to apply a liquid lubricant on the protective film in order to enhance the corrosion resistance.

In this case, when the amount of the lubricant is reduced by scattering the liquid lubricant from the surface of the disk by the sliding of the magnetic head and the rotating magnetic disk, or by decomposing and evaporating the liquid lubricant, the sliding characteristics are deteriorated. The holding mechanism of the magnetic head may be destroyed due to the increase in the coefficient of dynamic friction between the magnetic head and the magnetic disk. Conversely, if the lubricant is too much or the fluidity is too good, the lubricant collects around the magnetic head that is in contact with the magnetic disk while the magnetic disk is stopped, and the magnetic head and the magnetic disk stick together. Furthermore, in a small magnetic recording device built into a personal computer such as a notebook computer, the environment in which it is used may fluctuate drastically in high temperature and high humidity environments such as general indoors, sometimes outdoors, and even automobiles. It is desired that the liquid lubricant exert a stable lubricating action on the protective film in a wide temperature range from high temperature to low temperature. As described above, it has been known that in the magnetic recording device, the adhesion of the lubricant to the protective film affects durability and reliability.

In order to solve such a problem of the adhesion of the lubricant to the protective film, various studies have been made in the past, for example, as disclosed in JP-A-61-155345, an anchor. A technique has been proposed in which a high-performance fluorine-based lubricant such as perfluoropolyether having an end group having a function (easy to bond to a base and difficult to peel) is applied on a protective film.

[0005]

However, even with such a lubricant that is excellent in anti-scattering property and chemically stable, the recent increase in the rotational speed of the magnetic disk and the magnetic property of the magnetic head have been improved. With the decrease in the flying height from the disk, it has become unavoidable that the lubricant scatters and decreases when the magnetic head and the magnetic disk slide. In particular, it has been known that the contact temperature between the magnetic head and the rotating magnetic disk rises to several hundreds of degrees Celsius, and the mechanism by which the perfluoropolyether-based lubricant is released / decomposed and reduced accordingly has been clarified. This is because the surface of the carbon protective film is originally relatively stable, and the adhesion force does not increase so much even if the amount of adhesion increases even if the end groups are added. In addition, in the process of applying a lubricant using a lubricant solution, which is said to be the most general and stable method of forming a lubricant film, using a chemically active end group may deteriorate the protective film itself or even the magnetic film. There was a fear that it could not be used easily, and there was no choice but to apply it without sufficiently removing the contaminants existing at the interface between the lubricant and the protective film.

Therefore, the present invention has been made in view of the above points, and a first object of the present invention is to make the lubricant hard to scatter from the surface of the protective film when the magnetic head and the rotating magnetic disk slide. It has an interface between a lubricating film and a protective film that are connected by various bonding forces, and changes in the environment where the magnetic recording device is placed,
That is, it is an object of the present invention to provide a recording medium that is resistant to temperature changes, humidity changes, and atmospheric pressure changes, has less damage to the lubricating film due to contaminants, has excellent environmental resistance, and has excellent durability and reliability.

A second object is to provide an improved manufacturing method capable of easily manufacturing such a recording medium having excellent durability and reliability.

Further, a third object is to provide a manufacturing apparatus which can easily carry out the improved manufacturing method.

[0009]

A first object of the present invention is to provide a magnetic recording medium in which at least a magnetic film, a protective film, and a lubricating film are sequentially laminated on the surface of a non-magnetic substrate. This is achieved by a magnetic recording medium having a radical reaction product layer interposed at the interface. As the radical reaction product, the protective film and the lubricating film are, for example, fluorine,
It is composed of a reaction product formed by reacting with at least one radical of carbon, boron and oxygen. As the protective film, for example, an amorphous carbon or a carbon-based protective film having a diamond structure is preferable, but in addition, a nitride such as cubic boron nitride, silicon oxide such as silica, or the like may be used.

A second object of the present invention is to provide a method of manufacturing a magnetic recording medium, which comprises a step of sequentially laminating and forming at least a magnetic film, a protective film and a lubricating film on the surface of a non-magnetic substrate. A method for manufacturing a magnetic recording medium, in which a radical reaction product layer is formed at least at the interface between the protective film and the lubricating film by adding a step of radically treating the surface of the lubricating film of the substrate after the forming step. To be done. Then, it is preferable to add a step of irradiating the surface of the lubricating film with at least one light in an infrared region and an ultraviolet region, preferably together with the step of performing the radical treatment. This allows 30kc between the surface of the protective film and the lubricant molecule.
A bond having a binding energy of al / mol or more can be generated.

The radicals that act on the interface between the lubricating film and the protective film to immobilize the lubricant on the surface of the protective film are:
At least one kind of one-atom radical of at least one kind of fluorine, carbon, nitrogen, boron and oxygen, or at least one kind of molecular radical composed of a combination of a plurality of elements can be mentioned.

As one of the radical generation methods in the above radical treatment step, there is a method of generating radicals by supplying a radical source gas containing at least one element of fluorine, carbon, boron and oxygen in the presence of plasma. Then, as a plasma generation source when the radical source gas is supplied in the presence of plasma to generate radicals, for example, a direct current glow discharge using a rare gas such as Ar as a discharge gas, a capacitive coupling type or an inductive coupling type RF discharge, It can be composed of at least one of microwave discharge, corona discharge, silent discharge, electron cyclotron resonance plasma, and shock wave plasma.

Further, as another method for producing radicals in the above-mentioned radical treatment step, a gaseous precursor for radical generation is irradiated with a laser in the ultraviolet region or infrared region, or irradiated with synchrotron orbital radiation. There is a method of generating radicals by dielectric breakdown or photolysis. The laser may emit a single wavelength or a plurality of wavelengths. Examples of the above-mentioned gaseous precursors for radical generation include gases such as fluorine, carbon tetrafluoride, halogenated carbon such as perfluoroethane, and hydrocarbons.

Furthermore, as one of the other radical generation methods in the above radical treatment step, there is a method of irradiating a solid or liquid raw material target for radical generation with a laser in the ultraviolet or infrared region to generate radicals. This method is known as a method of producing by ablation of a solid or liquid surface with a laser in the ultraviolet region or infrared region, and examples of the ablation target include polytetrafluoroethylene and perfluoropolyether.

In the above radical treatment step, it is also effective to perform radical treatment in the coexistence of perfluoroalkene or perfluoroalkyne when the surface of the lubricating film is irradiated with radicals.

Here, examples of the recording medium include a magnetic disk having a contact type or partial contact type magnetic head, a magnetic tape, and a magneto-optical disk. As the substrate of the magnetic disk, for example, a non-magnetic substrate made of aluminum alloy, glass, graphite or the like is used. The surface of the aluminum alloy substrate may be plated with nickel / phosphorus or the like. In addition, as texturing, by pressing diamond abrasive grains or polishing tape while rotating the substrate, fine concentric grooves are formed on the substrate to improve the flying characteristics of the head and control magnetic anisotropy. Things such as doing are also done. Furthermore, on the glass substrate,
It is also possible to etch the surface with a chemical such as a strong acid to make fine irregularities, reduce the area in contact with the head, and reduce the tangential force during sliding.

Before the recording film is formed on the substrate of the magnetic disk, chromium or the like may be formed as a base film by a sputtering method or the like in order to improve the magnetic characteristics of the recording film. .. As the magnetic recording film on the magnetic disk substrate,
Cobalt-nickel, cobalt-chromium, cobalt-chromium, and platinum, tantalum, vanadium, samarium, etc. mixed in small amounts are used.

As described above, as the protective film on the magnetic disk substrate, it is general to use, for example, an amorphous carbon protective film as the carbon-based protective film. As a method of forming this amorphous carbon protective film, a method of forming by sputtering in an inert gas targeting graphite or a mixed gas of an inert gas and a hydrocarbon gas such as methane, a hydrocarbon gas, A method of forming an organic compound such as alcohol or acetone alone or by mixing with hydrogen gas, an inert gas, etc. by plasma CVD, or a method of ionizing the organic compound and accelerating it by applying a voltage to make it collide with a substrate. and so on. Further, instead of the amorphous carbon protective film, it is possible to use, for example, a cubic boron nitride film formed by a plasma CVD method using borohydride, ammonia and hydrogen as raw materials.

A perfluoropolyether lubricant containing carbon, fluorine and oxygen is generally applied on the protective film on the magnetic disk substrate. As the main chain structure, those represented by the formulas (1), (2) and (3) in Table 1 below are used.

[0020]

[Table 1]

However, n and m in these formulas are positive integers and are determined by the molecular weight, and the average molecular weight is preferably about 1,500 to 10,000. The end groups need not be attached. When using a terminal group, a neutral group such as a fluoroalkyl group and an acidic group such as a hydroxyl group, a carboxylic acid group or an ether group are preferably attached to one or both ends.

As a method of applying these lubricants, the lubricant is dissolved in an organic solvent such as Freon, and the magnetic disk on which a protective film is formed is dipped in the solution, and then 0.1 to 5 m.
There is a method of pulling up at a slow speed of m / s. The magnetic disk may be immersed in the lubricant solution so that the lubricant molecules adhere firmly to the protective film, and then left for a while. Also, the lubricant solution may be stirred during the immersion. After pulling up from the lubricant solution, it may be further immersed in an organic solvent in order to remove the excess lubricant having weak adhesion. Further, ultrasonic waves may be applied during immersion in the lubricant solution or the organic solvent. The lubricating film thus obtained is usually an extremely thin film having a thickness of several nm.

[0023]

When the interface between the lubricant formed on the protective film and the protective film is irradiated with radicals, the lubricant molecules near the interface and the surface of the protective film are excited. There are mainly two effects of interface excitation by the radicals. One is the effect of causing a reaction between the lubricant molecules near the interface and the surface of the protective film, and the other is the effect of eliminating contaminants on the surface of the protective film before the lubricant application process near the interface. ..
Among them, the former reaction forms a radical reaction product between the lubricant molecule and the surface of the protective film to form a strong chemical bond. Other reactions excited by radicals include cleavage and recombination of lubricant molecules, and modification (modification) of the protective film surface. As a result, the lubricant molecules are shortened at some places and intricately entangled with each other at some places to have a structure that is difficult to be dispersed. These effects are further promoted if radicals are generated by plasma generated by discharge near the protective film. This is because various electromagnetic waves such as electrons and ultraviolet rays generated from plasma reach the interface between the lubricant and the protective film.

When the radical irradiation is carried out in the presence of a perfluoroalkene or a perfluoroalkyne, the radicals react with these perfluoro compounds, and a part of the generated fluorinated alkyl radicals is protected on the lubricant surface or partially exposed. It can further react with the film surface and enhance the lubricating film.

Further, when radicals are allowed to act on the lubricant and the surface of the protective film, by irradiating light in the infrared region or ultraviolet region at the same time or after the irradiation, 30 kcal / mol or more is provided between the surface of the protective film and the lubricant molecule. Bonds having a binding energy of can be densely generated. This is because light in the infrared region or ultraviolet region is less likely to be absorbed by the protective film having a thickness of several tens of nm, and the interface between the protective film and the lubricating film can be efficiently excited. This, together with the effect of radical irradiation, promotes the formation of chemical bonds between the lubricant molecules and the surface of the protective film. The light irradiation also has the effect of exciting contaminants, mainly hydrocarbons of small molecular weight, existing at the interface between the protective film and the lubricating film, which interferes with the formation of chemical bonds, and remove them to the outside of the film.

Due to the effects based on these effects, the magnetic recording apparatus is resistant to environmental changes, that is, temperature changes, humidity changes, and atmospheric pressure changes, and is excellent in environmental resistance with little damage to the lubricating film due to contaminants. A recording medium is obtained, and further, a recording medium having no contaminants on the surfaces of the lubricating film and the protective film is obtained.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. <Embodiment 1> FIG. 1 is a schematic sectional view of a recording medium for explaining one embodiment of the present invention. In the figure, 1 is a disk substrate (for example, a 5.25-inch disk) made of an aluminum alloy plated with nickel-phosphorus, and a thickness of 500 nm is formed on the disk substrate by sputtering.
The chromium underlayer film 2, the cobalt-nickel magnetic film 3 having a thickness of 50 nm, and the amorphous carbon protective film 4 having a thickness of 50 nm are sequentially formed by the continuous transfer film forming apparatus. Further, a perfluoropolyether-based polymer lubricant 5 (without end functional group, molecular weight of about 4000) was applied thereon by a dip method using a Freon solution (concentration 0.2 wt%) with a thickness of 5 nm. There is. The dip time is 5 minutes, and the pulling rate is 2 mm / s.

Then, this disk was placed in the radical irradiation device shown in FIG. 2 and irradiated with radicals. In FIG. 2, 6 is a 5.25 inch magnetic disk having a lubricating film formed thereon, 7 is an electrode for direct current glow discharge, and 8 is a chamber. After setting the magnetic disk, the inside of the chamber was evacuated from the exhaust port 21 by a turbo molecular pump (not shown). After that, the chamber 8 is closed,
Fluorine serving as a radical precursor is supplied from the gas inlet 22 to 50
mTorr, 300 mTorr of argon as discharge gas
After introducing r, glow discharge was generated under the conditions of voltage of 2,000 V and discharge time of 5 minutes to radically treat the surface of the magnetic disk 6. Then, after the discharge gas was once degassed, it was purged with nitrogen gas and the pressure inside the chamber was returned to the atmospheric pressure, and the magnetic disk was taken out from the chamber. Thus, the radical reaction product layer 2 is formed at the interface between the protective film 4 and the lubricating film 5.
5 was formed.

As a comparative example, a magnetic disk not irradiated with radicals (hereinafter referred to as a reference disk).
Prepared separately. The characteristics of these two were compared according to the following method. First, in order to test the adhesion of the lubricant to the protective film, an ultrasonic cleaning experiment by immersion in Freon was performed. The magnetic disk and the reference disk of this example were immersed in Freon of 10 liters for 5 minutes while applying ultrasonic waves. Then, the two disks were pulled up at a speed of 2 mm / s. This washing was repeated 3 times in total. After cleaning, the film thickness of the lubricant was measured by quantifying the CF stretching vibration by Fourier transform infrared spectroscopy (FT-IR high-sensitivity reflection method). Then, it was confirmed that the disk of this example had a film thickness of 4.5 nm (initially formed to be 5 nm), the lubricant film was firmly fixed by radical irradiation, and the scattering property was remarkably improved.

Next, in order to test the durability and reliability of the magnetic disk, contact start stop (Con)
tact Star Top CSS is abbreviated) test.
This CSS test is a drive test of a magnetic disk drive in which a cycle of rotating a magnetic disk with a slider mechanism fixed, flying a magnetic head, and then stopping the disk is repeated at regular intervals. In the CSS test, the rotation speed of the magnetic disk is 5,000 rpm and the flying height of the magnetic head is 100 n when reaching a certain speed.
m, the outside air temperature is 24 ° C.

As a result, in the reference disk, the surface of the magnetic disk was damaged after 30,000 repetitions, whereas in the case of the disk of the present embodiment, even after 100,000 repetitions. No damage was observed on the surface of the magnetic disk and the durability was at least 3 times.
Further, when the film thickness of the lubricant on the surface of the magnetic disk was measured by the microscopic FT-IR (minimum analysis area 25 μm square) after the CSS test, in the reference disk, the part where the slider was in contact (sliding part) was 0.1 nm. On the other hand, in the disk of the present example, the number of repetitions was three times or more compared to the reference disk, but a sufficient amount of lubricant of 3.4 nm remained, and when the disk was slid by radical irradiation. It was confirmed that the scattering of the lubricant was suppressed.

Furthermore, an environmental test was conducted in which the magnetic disk of this example and the reference disk were left in an environment of constant temperature and humidity of 80 ° C. and 90% RH for 100 hours. As a result, 14 corrosion points appeared on the reference disk. On the other hand, in the disc of this example, no corrosion point was found at all.

<Embodiment 2> FIG. 3 is a schematic sectional view of a magnetic disk manufacturing apparatus according to another embodiment of the present invention. Hereinafter, similar to Embodiment 1, the description will be made with reference to the drawings. In the figure, 6 is a magnetic disk to be subjected to radical treatment, 9 is a vacuum chamber, and 10 is a plasma CVD electrode. The magnetic disk 6 is a disk substrate (for example, 3.5 inch disk) made of tempered glass, on which a chromium underlayer film having a thickness of 400 nm and a cobalt chromium chromium platinum magnetic film having a thickness of 40 nm are sequentially formed. An amorphous carbon film having a thickness of 10 nm was formed thereon by the plasma CVD method using methane as a raw material. A perfluoropolyether lubricant having a thickness of 3 nm was applied to the magnetic disk by spin coating. After that, this magnetic disk is put into the vacuum chamber 9 and the exhaust port 21 is evacuated, and then carbon tetrafluoride 20 mTorr and fluorine 5 are used as radical precursors from the gas inlet 22.
Flow 0mTorr at a flow rate of 20sccm and output 800
Plasma CVD was performed for 10 seconds for W to perform radical treatment. The radicals in this example include carbon and fluorine.

The thus-formed magnetic disk of this example was subjected to a CSS test under the same conditions as in Example 1 to evaluate its life. As a result, in the case of this example, the magnetic disk was not damaged even after the number of repetitions of 150,000, and the lubricant film thickness of the sliding portion after the test was quantified by the same microscopic FT-IR as in Example 1. Then, it became 2.1 nm (initial film thickness was 3 nm), and it was found that high lubricant scattering resistance was achieved by radical irradiation.

Further, a heat dissipating property test was conducted by leaving it in a nitrogen atmosphere at 200 ° C. for 100 hours, and it was found that the reference disk not subjected to radical irradiation had a lubricating film thickness of 3
In contrast to the decrease of 5% in the magnetic disk of this example, the reduction rate of the lubricating film thickness after the test was only 5%, and it was confirmed that the thermal scattering property by the radical irradiation was improved.

<Embodiment 3> FIG. 4 is a schematic sectional view of a magnetic disk manufacturing apparatus according to another embodiment of the present invention. A description will be given below with reference to the drawings as in the case of the first embodiment. In FIG.
12 is a quartz condenser lens (f = 200 mm) that also serves as an introduction window for the laser beam 23, 24 is a laser beam stopper, and 13
Is a disk rotating mechanism, 14 is a nozzle for introducing a perfluoroalkene gas, and 15 is a 150 W low-pressure mercury lamp for irradiating ultraviolet light. The disc rotating mechanism 13 can be moved up and down, and the distance between the condensing point of the laser 23 and the disc 6 can be arbitrarily changed.

The magnetic disk 6 has the same 3 nm as in the second embodiment.
It is a magnetic disk with a lubricating film having a film thickness of. The magnetic disk is rotated at 20 rpm by a disk rotation mechanism, the inside of the chamber is evacuated from the exhaust port 21, and then hexafluoroethane 10 Torr and fluorine 10 Torr as radical precursors are flown from the gas inlet 22 at 20 sccm and at the same time from the nozzle 14. 3T perfluoropropene
Orr was passed at 5 sccm, ArF excimer laser light (193 nm, 200 mJ / pulse, 50 Hz) was condensed by the quartz condenser lens 12, and dielectric breakdown (breakdown) was performed for 5 minutes for radical treatment. The low-pressure mercury lamp 15 was also turned on at the same time during the laser beam focusing. The radicals in this example include carbon and fluorine. After the above process,
When the lubricating film thickness of the magnetic disk was measured by FT-IR, it was slightly increased from 3.0 nm before processing to 3.4 nm. This is due to the photodielectric breakdown and the mechanism for reinforcing the lubricating film by the irradiation of ultraviolet light.

The life of the thus-formed magnetic disk of this example was evaluated by a CSS test under the same conditions as in Example 1. As a result, in the magnetic disk of the present example, no damage was observed in the magnetic disk even after the number of repetitions was 950,000, and the microscopic FT- was the same as in Example 1.
Quantifying the lubricating film thickness of the sliding part after the test by IR is 2.1n
m (the initial film thickness was 3 nm), and it was revealed that the radical treatment improved the scattering resistance during sliding.

Further, the magnetic disk and the reference disk of this embodiment were subjected to a continuous writing / reading test of 10 MB of data under the environment of 60 ° C. and 40% RH.
In the reference magnetic disk, an error appeared 2 hours after the start of the test, whereas in the case of the present embodiment, the normal writing / reading operation was performed even after 24 hours, and High environmental resistance was confirmed.

<Embodiment 4> FIG. 5 is a schematic sectional view of a magnetic disk manufacturing apparatus according to another embodiment of the present invention. Referring to the drawings, 6 is a magnetic disk, 13 is a disk rotating mechanism, and 16 is a target for laser ablation that produces radicals (in this embodiment, tetrafluoropolyethylene coated with perfluoropolyether grease on the surface thereof). Plate), 17 is a convex mirror made of synthetic quartz, 18 is a vacuum chamber, 19 is a linear movement mechanism for switching between the convex mirror and the target for ablation, and 20 is a quartz window for incidence of the ultraviolet laser light 23. 22 is a gas inlet.

2. A lubricating film was formed in the same manner as in Example 2.
Put the 5-inch magnetic disk 6 in the chamber 18 and evacuate it from the exhaust port 21 while rotating it to 30 rp.
Rotated at m. Then, KrF excimer laser light (248 nm) was made incident from the quartz window 20 by the quartz lens 12 of f = 600 mm, and focused on the ablation target 16. The irradiation condition is 400 mJ / pulse, repetition is 100 Hz, and irradiation time is 1 minute. By this ablation, radicals containing fluorine, carbon and oxygen were generated from the target 16, and the disk surface was radical-treated.

After the ablation, the laser beam 23 is directed to the convex mirror 17 by the linear moving mechanism 19, and tetrafluoroethylene is fed at 1 Torr from the gas inlet 22.
While introducing at 50 sccm, the quartz lens 12 was removed, and the disk surface was irradiated with laser light for 2 minutes while defocusing under the condition of 10 mJ / pulse.

The life of the magnetic disk of this example which had been subjected to the radical treatment and the excimer laser light irradiation treatment in this way was evaluated by a CSS test under the same conditions as in the first embodiment. As a result, in the magnetic disk of this example, no damage was observed in the magnetic disk even after the number of repetitions of 850,000, and the lubricating film thickness of the sliding portion after the test was performed by the same microscopic FT-IR as in Example 1. Was determined to be 1.8 nm (the initial film thickness was 3 nm), and it was revealed that the radical treatment improved the scattering resistance during sliding.

Example 5 Instead of the fluorine gas used as the radical precursor in Example 1, ammonia gas was used in this example, and radical treatment was carried out in the same manner as in Example 1. In this case, the radicals produced contained nitrogen, and the results of radical treatment were almost the same as in Example 1.

Example 6 In place of the fluorine gas used as the radical precursor in Example 1, diborane (B ₂ H ₆ ) was used in this example to carry out the radical treatment in the same manner as in Example 1. In this case, the generated radicals contained boron, and the result of the radical treatment was almost the same as that of Example 1.

[0046]

As described above in detail, the present invention has achieved the intended purpose. That is, according to the first object achieving means, the reaction product layer is formed by radical irradiation at the interface between the lubricant formed on the protective film and the protective film, and a strong chemical bond is generated, resulting in the durability of the lubricating film. It was possible to realize a recording medium with marked improvement.

Further, according to the second object achieving means, it becomes possible to easily obtain a recording medium in which the durability of the lubricating film is remarkably improved by various radical treatments. That is, the radical treatment excites the lubricant molecules near the interface between the lubricant film and the protective film and the surface of the protective film. This interface excitation has an effect of causing a reaction between the lubricant molecules near the interface and the surface of the protective film and an effect of eliminating contaminants attached to the surface of the protective film before the lubricant coating step near the interface. A strong chemical bond is generated between the lubricant molecule and the surface of the protective film by the former reaction, and in addition, cleavage and recombination of the lubricant molecule and modification (modification) of the surface of the protective film are performed. As a result, the lubricant molecules are shortened at some places and intricately entangled with each other at some places to have a structure that is difficult to be dispersed. For this reason, the deterioration of the sliding characteristics due to the reduction and dispersion of the lubricating film is alleviated even while sliding with the magnetic head, and a recording medium having a long life and excellent reliability is realized.

In addition to the above effects, when a radical is made to act, the binding energy between the protective film surface and the lubricant molecule is further strengthened by irradiating light in the infrared or ultraviolet region at the same time or after the action. (30 kcal / mol
The above can be generated. This, together with the effect of radical irradiation, promotes the formation of dense chemical bonds between the lubricant molecules and the surface of the protective film. The light irradiation also has the effect of exciting contaminants, mainly hydrocarbons of small molecular weight, existing at the interface between the protective film and the lubricating film, which interferes with the formation of chemical bonds, and remove them to the outside of the film. Due to these effects, it is possible to realize a recording medium which is resistant to environmental changes in the magnetic recording apparatus, that is, temperature changes, humidity changes, and atmospheric pressure changes, and which is less likely to damage the lubricating film due to contaminants and has excellent environmental resistance.

Further, according to the third object achieving means, it is possible to realize the radical processing tank value with a relatively simple structure, and the recording medium manufacturing method which is the second object achieving means can be easily carried out. I was able to do it.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a main part of an embodiment of a recording medium of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part of an apparatus configuration for explaining a recording medium manufacturing method and a manufacturing apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a main part of a device configuration according to another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a main part of a device configuration according to another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a main part of a device configuration according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Aluminum alloy substrate with nickel plating, 2 ... Chrome film, 3 ... Magnetic recording film, 4 ... Protective film, 5 ... Lubrication film, 6 ... Magnetic disk, 7 ... DC glow discharge electrode, 8 ... Vacuum chamber, 9 ... CVD With vacuum chamber, 10 ... CV
Electrode for D, 11 ... Vacuum chamber for dielectric breakdown, 12 ... Quartz condensing lens, 13 ... Disk rotation mechanism, 14 ... Gas introduction nozzle, 15 ... Low-pressure mercury lamp, 16 ... Laser ablation target, 17 ... Quartz convex mirror , 18 ... Vacuum chamber for laser ablation, 19 ... Linear movement mechanism, 20 ... Quartz window, 21 ... Exhaust port, 22 ... Gas inlet port, 23 ... Laser light, 24 ... Laser stopper, 25 ... Radical reaction product layer.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication C10N 30:06 30:08 40:18 50:08 (72) Inventor Naruhiko Fujimaki Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa No. 292 Co., Ltd.Hitachi Manufacturing Technology Research Center

Claims (16)

[Claims] 1. A magnetic recording medium in which at least a magnetic film, a protective film, and a lubricating film are sequentially laminated on the surface of a non-magnetic substrate, and a radical reaction product layer is interposed at the interface between the protective film and the lubricating film. Magnetic recording medium. 2. The magnetic recording medium according to claim 1, wherein the radical reaction product is a reaction product of a protective film, a lubricating film, and at least one radical of fluorine, carbon, boron and oxygen. 3. The protective film comprises a carbon-based protective film,
The magnetic recording medium according to claim 1 or 2, wherein the lubricating film comprises a fluorine-based organic polymer film. 4. A method of manufacturing a magnetic recording medium, comprising a step of sequentially laminating and forming at least a magnetic film, a protective film and a lubricating film on a surface of a non-magnetic substrate, wherein the substrate is formed after the step of forming the lubricating film. A method of manufacturing a magnetic recording medium, wherein a radical reaction product layer is formed at least at the interface between the protective film and the lubricating film by adding a step of radically treating the surface of the lubricating film. 5. The method for manufacturing a magnetic recording medium according to claim 4, further comprising the step of irradiating the surface of the lubricating film with at least one light in the infrared region and the ultraviolet region together with the step of performing the radical treatment. 6. In the step of performing the radical treatment, a radical source gas containing at least one element of fluorine, carbon, boron and oxygen is supplied in the presence of plasma to generate radicals, and the surface of the lubricating film is irradiated with the radicals. 6. The method for manufacturing a magnetic recording medium according to claim 4, which comprises the step of: 7. A direct current glow discharge in which a rare gas is used as a discharge gas is used as a plasma generation source in a step of supplying the radical source gas in the presence of plasma to generate radicals, and irradiating the radical film with the radicals. 6. The method for producing a magnetic recording medium according to claim 4, comprising at least one of discharge, microwave discharge, corona discharge, silent discharge, electron cyclotron resonance plasma and shock wave plasma. 8. In the step of performing the radical treatment, a radical-generating gaseous precursor is irradiated with a laser in an ultraviolet region or an infrared region, or is irradiated with synchrotron orbit radiating light to generate radicals, and the radicals are generated. 6. The method of manufacturing a magnetic recording medium according to claim 4, which comprises a step of irradiating the surface of the lubricating film. 9. The step of subjecting the radical treatment to a step of irradiating a solid or liquid raw material target for radical generation with a laser in the ultraviolet region or infrared region to generate radicals, and irradiating the surface of the lubricating film with the radicals. Item 4. A method of manufacturing a magnetic recording medium according to Item 4 or 5. 10. The method for producing a magnetic recording medium according to claim 4, wherein the step of performing the radical treatment is a step of treating in the presence of perfluoroalkene or perfluoroalkyne. 11. A radical processing chamber, means for generating radicals in the chamber, means for holding a magnetic recording medium in which a protective film is coated in advance with a lubricating film in the chamber, and radical generating means. An apparatus for manufacturing a magnetic recording medium, comprising: radical processing means for irradiating the surface of the lubricating film with the radicals. 12. A magnetic recording medium manufacturing apparatus according to claim 11, wherein said radical generating means is means for supplying radical source gas in the presence of plasma to generate radicals. 13. The plasma generating means comprises means for discharging a rare gas by at least one method of direct current glow discharge, RF discharge, microwave discharge, corona discharge, silent discharge, electron cyclotron resonance plasma and shock wave plasma. 13. The magnetic recording medium manufacturing apparatus according to claim 12. 14. The apparatus for producing a magnetic recording medium according to claim 11, wherein the radical generating means is means for irradiating a solid or liquid raw material target for generating radicals with a laser in the ultraviolet region or infrared region to generate radicals. .. 15. The apparatus for manufacturing a magnetic recording medium according to claim 11, further comprising means for irradiating the surface of the lubricating film with at least one light in the infrared region and the ultraviolet region together with the radical generating means. 16. The apparatus for producing a magnetic recording medium according to claim 11, further comprising a means for introducing a perfluoroalkene or a perfluoroalkyne together with the radical generating means.