JP2001014657A - Magnetic recording medium and manufacture of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic recording medium excellent in fly-stiction characteristics and its manufacturing method. SOLUTION: A magnetic recording medium is manufactured in such processes lubricating film is formed on a disk D which has a carbon protective film formed by a plasma CVD method on a magnetic film that is formed on a non- magnetic base film formed on a non-magnetic substrate. Etching is applied to the surface of the carbon protective film by means of plasma generated from a etching gas, utilizing an etching device 2 prior to forming the lubricating film. Thereby, lubricant become strongly bondable to the highly active surface of the protective film, and at the same time impurities adhered to the surface of the protective film can be removed from the protective film.

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 used for a magnetic disk drive and the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording medium, a nonmagnetic base film and a magnetic film are provided on a nonmagnetic substrate, and a protective film made of carbon or the like is formed thereon. One provided with a lubricating film made of a lubricant such as perfluoropolyether is used. In recent years, it has been required to increase the recording density of a magnetic recording medium, and a magnetic recording medium that can reduce spacing loss has been demanded. As a method for forming the carbon protective film, a sputtering method is generally used. However, if the carbon protective film formed by the sputtering method is formed thin (for example, a film thickness of 100 ° or less) in order to reduce spacing loss, durability will be improved. May be insufficient. For this reason, the use of a plasma CVD method is being studied as a method capable of forming a carbon protective film having sufficient durability even when it is made thin.

[0003]

However, in the magnetic recording medium manufactured by the above-mentioned conventional technique, the lubricant tends to adhere to the magnetic head, and the fly stiction characteristics are sometimes deteriorated. When the fly stiction characteristics are reduced, the flight stability of the head is reduced,
Problems such as head crash due to contact between the protective film and the head are likely to occur. The present invention has been made in view of the above circumstances, and has as its object to provide a magnetic recording medium having excellent fly stiction characteristics and a method for manufacturing the same.

[0004]

According to a method of manufacturing a magnetic recording medium of the present invention, prior to forming a lubricating film, the surface of the carbon protective film is etched using plasma generated from an etching gas. Things. When etching the surface of the carbon protective film, plasma can be generated by applying high frequency power to the disk on which the carbon protective film is formed. The magnetic recording medium of the present invention is a magnetic recording medium manufactured by the above manufacturing method, wherein the amount of oxygen on the surface of the carbon protective film measured by X-ray photoelectron spectroscopy is 2.9 to 12%. It is a feature. The B / A value of the carbon protective film measured by Raman spectroscopy was 1.22.
It is preferably set to ~ 1.65. The magnetic recording medium of the present invention is a magnetic recording medium manufactured by the above manufacturing method, wherein the amount of nitrogen on the surface of the carbon protective film measured by X-ray photoelectron spectroscopy is 5.0 to 16.5%. It can also be characterized by the following. In this case, B / B of the carbon protective film measured by Raman spectroscopy was used.
The A value is preferably 1.21 to 1.52.

[0005]

FIG. 1 shows an etching apparatus 2 used in one embodiment of a manufacturing method of the present embodiment. The etching apparatus 2 shown here is a chamber 20 for accommodating a disk to be etched. And the chamber 20
A high-frequency power supply 21 for applying high-frequency power to the internal disk is provided. Reference numeral 24 denotes a matching unit.

The chamber 20 is connected to an introduction pipe 25 for introducing an etching gas supplied from a supply source (not shown) into the chamber 20 and an exhaust pipe 26 for discharging the gas in the chamber 20 to the outside of the system. . The exhaust pipe 26 is provided with an exhaust amount adjusting valve 27, and the internal pressure of the chamber 20 can be set to an arbitrary value by adjusting the exhaust amount.

FIG. 2 shows a plasma CVD apparatus 1 used in the present embodiment.
The apparatus 1 includes a chamber 10 for accommodating a disk on which a protective film is to be formed, electrodes 11, 11 installed on inner surfaces of both side walls of the chamber 10, and these electrodes 11,
High-frequency power supplies 12 and 12 for supplying high-frequency power to 11,
Bias power supply 1 connected to disk in chamber 10
3 and a source gas supply source 14 for forming a protective film to be formed on the disk.

The chamber 10 has an introduction pipe 15 for introducing the source gas supplied from the supply source 14 into the chamber 10,
15 and an exhaust pipe 16 for discharging gas in the chamber 10 to the outside of the system. The exhaust pipe 16 is provided with an exhaust amount adjusting valve 17 so that the internal pressure of the chamber 10 can be set to an arbitrary value by adjusting the exhaust amount. As the bias power supply 13, a pulse DC power supply or a high-frequency power supply can be used.

The plasma CVD apparatus 1 and the etching apparatus 2 are connected to each other so that the disk D in the plasma CVD apparatus 1 can be transferred into the etching apparatus 2 without being exposed to the outside air.

Next, an embodiment of the method for manufacturing a magnetic recording medium according to the present invention will be described by taking as an example the case where the apparatus shown in FIGS. 1 and 2 is used. First, a non-magnetic base film and a magnetic film are formed on both surfaces of a non-magnetic substrate by using a method such as a sputtering method, and a disk D is obtained. As the non-magnetic substrate, a substrate generally used as a substrate for a magnetic recording medium can be used, and an aluminum alloy substrate on which a NiP plating film is formed, or a substrate made of glass, silicon, or the like can be used. The non-magnetic substrate is preferably subjected to a texture treatment such as a mechanical texture treatment on its surface, and it is particularly preferable to use a substrate having a surface average roughness Ra of 1 to 20 °.

As a material for the nonmagnetic underlayer, Cr or a Cr alloy can be used.
It is preferable to use a / Ti-based, Cr / W-based, Cr / V-based, or Cr / Si-based alloy. As the material of the magnetic film, C
o alloy can be used. As the Co alloy, Co /
Cr system, Co / Cr / Ta system, Co / Cr / Pt system, C
It is preferable to use an alloy such as an o / Cr / Pt / Ta system. The thickness of each of the non-magnetic base film and the magnetic film is 5
It is preferably 0 to 1000 ° and 50 to 800 °.

Next, the disk D is loaded into the chamber 10 of the plasma CVD apparatus 1 shown in FIG.
The gas in the chamber 10 is exhausted through the exhaust pipe 16 while the source gas supplied from the supply source 14 is introduced into the chamber 10 through the introduction pipe 15, and the gas is circulated in the chamber 10. Expose to gas. As the source gas, a gas containing a hydrocarbon, for example, a gas mainly containing a mixed gas of a hydrocarbon and hydrogen can be used.

As the hydrocarbon, it is preferable to use one or more of lower saturated hydrocarbons, lower unsaturated hydrocarbons, and lower cyclic hydrocarbons. As the lower saturated hydrocarbon, methane, ethane, propane, butane, octane and the like can be used. Further, as the lower unsaturated hydrocarbon, isoprene, ethylene, propylene, butylene, butadiene and the like can be used. As the lower cyclic hydrocarbon, benzene, toluene, xylene, styrene, naphthalene, cyclohexane, cyclohexadiene and the like can be used. The term “lower” means that the carbon number is 1 to 10. Chamber 10
Is preferably 0.1 to 10 Pa.

At the same time, a high frequency power of preferably 50 to 2000 W is applied to the electrode 11 using a high frequency power source 12 to generate plasma, and the carbon protective film is formed on the disk D by plasma enhanced chemical vapor deposition using the above raw material gas as a raw material. Formed on both sides. The thickness of the carbon protective film is 30 to 100.
Å, preferably 30 to 75Å.

In forming the carbon protective film, it is preferable to apply a bias, for example, a high frequency bias or a pulse DC bias to the disk D using the bias power supply 13. When a high frequency bias is used as the bias, a high frequency power supply is used
A high frequency power of 300 W, preferably 10 to 150 W is applied to the disk D. When a pulse DC bias is used as the bias, a pulse DC power supply is used as the bias power supply 13, and the bias power supply is −400 to −10 V, preferably −30 V.
A voltage (average voltage) of 0 to −50 V is applied to the disk D. The pulse width of the pulse DC bias is 10 to
It is preferable that the frequency is 50000 ns and the frequency is 10 kHz to 1 GHz.

By forming a film using the plasma CVD apparatus 1, the carbon protective film contains a large amount of diamond-like carbon (hereinafter, referred to as DLC) component having high hardness and has excellent strength.

In the formed carbon protective film, active portions on the surface of the film involved in the film formation are hydrogenated, and there are many C—H bonds that are hardly polarized bonds. It can be said that the chemical activity on the film surface is lower than that of the protective film formed by the method.

When forming the carbon protective film, it is preferable to set the B / A value of the carbon protective film to the following value by adjusting the internal pressure of the chamber 10, the power applied to the electrode 11, and the like. When an inert gas such as Ar is used as an etching gas in an etching operation described later, the B / A value is 1.22 to 1.65 (preferably 1.2.
7 to 1.65, more preferably 1.29 to 1.65)
It is desirable that When a reactive gas such as N ₂ is used as an etching gas, the B / A value is 1.21.
１．５1.52 (preferably 1.24 to 1.52).

When the B / A value is less than the above range, the activity of the surface of the protective film becomes too high at the time of etching described later, and the affinity for the lubricant becomes excessive. That is,
When the B / A value is less than the above range, the content of the hydrocarbon-based polymer component in the protective film decreases, the number of C—H bonds that are chemically low-active bonds decreases, and the DLC component and the like are reduced. Includes more highly active bonds, such as C = C, C≡C bonds. For this reason, the number of highly active bonds becomes excessive at the time of etching described later, and the affinity for the lubricant becomes excessive. In general, a lubricating film is bonded to a film (a protective film or the like) immediately below the lubricating film at a portion (a base layer portion) near a lower surface facing the film immediately below the lubricating film.
The portion near the surface (surface layer) has fluidity, and the fluidity lowers the surface friction. However, if the affinity of the protective film surface for the lubricant becomes excessive, the thickness of the base layer increases and the surface layer increases. , The fluidity of the surface layer decreases, and the friction coefficient of the lubricating film surface increases.
Therefore, if the B / A value is less than the above range, the CSS characteristics of the obtained magnetic recording medium may be deteriorated. If the B / A value exceeds the above range, the number of CH bonds, which are low-active bonds in the protective film, increases, and the affinity of the protective film surface with the lubricant decreases during etching described later. It is not preferable because the bonding force between the lubricating film and the protective film is apt to decrease.

The B / A value indicates the ratio of the substantial peak value A excluding the fluorescent component in the G peak and the overall peak value B including the fluorescent component in the Raman spectrum. is there. A large B / A value means that the protective film contains a large amount of the hydrocarbon-based polymer component, and a small B / A value means that the polymer component content in the protective film is small, It means that there are many DLC components and graphite components.

After the formation of the carbon protective film, the source gas remaining in the chamber 10 may adhere as impurities to the surface of the formed protective film.

In the manufacturing method of this embodiment, the disk D on which the carbon protective film is formed is carried into the chamber 20 of the etching apparatus 2 shown in FIG. 1, and the carbon protective film is etched as follows. . An etching gas supplied from a supply source (not shown) is introduced into the chamber 20 through the introduction pipe 25, and the gas in the chamber 20 is exhausted from the exhaust pipe 26.
And the gas is circulated in the chamber 20 to expose the surface of the carbon protective film on both surfaces of the disk D to this etching gas.

As the etching gas, any gas that can generate plasma can be used. Specific examples include Ar, He, Ne, and K.
Examples thereof include inert gases such as r and Xe, and reactive gases such as N ₂ , O ₂ , H ₂ , organic nitrogen compounds, organic silicon compounds, organic fluorine compounds, and organic boron compounds. As the organic nitrogen compound, acetonitrile, pyridine, trimethylamine and the like can be used. As organic silicon compounds,
Tetramethylsilane, tetraethoxysilane and the like can be used. Octalfluorocyclobutane, octafluorocyclopentene, and the like can be used as the organic fluorine compound. As the organic boron compound, trimethylborane, triethylborane, or the like can be used.

When a gas containing oxygen, for example, O ₂ is used as an etching gas, a bond such as CＣO or C—O—C is formed on the surface of the protective film, as will be described later. Thus, there is an advantage that the surface activity is further increased and impurities attached to the surface of the protective film are oxidized and removed to clean the surface.

When an inert gas such as Ar is used as the etching gas, the etching gas hardly combines with the components of the protective film during etching, so that the components of the protective film cannot be gasified and scattered. For this reason,
Compared to the case of using an oxygen-containing gas that may generate a gas such as CO ₂ by reacting the protective film and the etching gas component, it is possible to prevent a change in the thickness of the protective film and facilitate the setting of the film thickness. it can. When a reactive gas such as N ₂ is used as an etching gas, a part of the etching gas is combined with a component of the protective film. At this time, a compound that easily gasifies is difficult to be generated. A change in thickness can be prevented, and setting of the film thickness can be facilitated.

At this time, it is preferable to adjust the internal pressure of the chamber 20 to the following value by appropriately adjusting the exhaust amount of the gas in the chamber 20 using the exhaust amount adjusting valve 27. That is, when an inert gas such as Ar is used as an etching gas, the pressure is 1.6 to 8 Pa (preferably 2.4 to 4.8 Pa). When a reactive gas such as N ₂ is used as an etching gas, the pressure is 2.4 to 8 Pa (preferably 2.4 to 6 Pa). When the internal pressure of the chamber 20 is less than the above range, the activity of the surface of the protective film is reduced, the bonding force between the protective film and the lubricating film is reduced, and the effect of enhancing the fly stiction characteristics of the magnetic recording medium is reduced. On the other hand, if the internal pressure exceeds the above range, the surface of the protective film becomes chemically unstable, and its durability may be reduced.

At the same time, using the high-frequency power source 21, preferably 30 to 500 W (more preferably 30 to 300 W
W, more preferably 30 to 200 W) is applied to the disk D to generate plasma using the etching gas as a raw material, and the plasma is used to etch the surface of the carbon protective film of the disk D. If the power applied to the disk D is less than the above range, the activity of the surface of the protective film is reduced, the bonding force between the protective film and the lubricating film is reduced, and the effect of enhancing the fly stiction characteristics of the magnetic recording medium is reduced. . If the power exceeds the above range, the surface of the protective film becomes chemically unstable, and the durability may be reduced. The frequency of the high-frequency power is not particularly limited, but it is 400 kHz which is easily available.
Preferably, z or 13.56 MHz is employed.

The etching time is preferably 2 to 6 seconds (preferably 3 to 5 seconds). This processing time
If it is less than the above range, the activity of the surface of the protective film decreases, the bonding strength between the protective film and the lubricating film decreases, and the effect of enhancing the fly stiction characteristics of the magnetic recording medium decreases. If the treatment time exceeds the above range, the surface of the protective film becomes chemically unstable, and its durability may be reduced.

When performing etching, the disk D
The surface of the protective film is adjusted by adjusting conditions such as power applied to the substrate, etching time, and internal pressure of the chamber 20.
It is preferable that the water contact angle is 70 degrees or less, preferably 60 degrees or less. If the water contact angle exceeds 70 degrees, the affinity of the protective film for the lubricant decreases, and the bonding strength between the lubricating film and the protective film decreases.

The surface of the carbon protective film that has been etched by the etching device 2 is in a state of being chemically highly active. This is for the following reason. By performing the etching, C—H bonds that are often present in the carbon protective film are broken by the plasma, and the broken C forms a new bond, for example, a bond such as CＣC or C≡C. When a gas containing nitrogen or oxygen is used as an etching gas, or when the surface of the protective film after etching is exposed to the atmosphere, C = N, C≡N, C = O, C—O−
Bonds such as C are also formed. These bonds are formed because the C, whose C—H bonds have been cut by plasma, forms dangling bonds that are chemically highly active, and the dangling bonds are bonded to each other. This is considered to be due to binding of nitrogen and the like.

C = O, C− generated by etching
Bonds such as OC, C = N, C≡N, C ＝ C, and C≡C can be said to have higher activities than C—H bonds.
This is for the following reason.

The activity of the protective film surface can be explained by the electronegativity of atoms present in the protective film (especially on the surface) and the dipole moment in the functional groups present. H, C, O,
Since the electronegativity of N is 2.1, 2.5, 3.5, and 3.0, respectively, the difference between the electronegativities of the two atoms constituting the CH bond is 0.4, whereas the difference between the electronegativities of the two atoms constituting the CH bond is 0.4. The difference between the electronegativities of the atoms of the species is 1.0, and the difference between the electronegativities of the two atoms constituting the C = N bond is 0.5. in this way,
C = O, C-O-C, C = generated by etching
In a bond such as N or C≡N, polarization is likely to occur due to a relatively large difference in electronegativity between constituent atoms, and ionicity is high and a dipole moment is large. For this reason, these bonds can be said to be chemically active. Further, in a bond such as C = C and C≡C, chemical activity is enhanced by π electrons which are nonlocal electrons. For the above reasons, the etched carbon protective film surface is considered to be in a chemically active state.

If impurities are attached to the surface of the protective film after passing through the plasma CVD apparatus 1, the impurities are removed from the surface of the protective film by plasma derived from an etching gas during etching.

The surface activity of the carbon protective film can be evaluated, for example, as follows. That is, first, the etched protective film surface is exposed to the air (hereinafter, referred to as an exposure step), and oxygen in the air is bonded to dangling bonds on the protective film surface. Then, X-ray photoelectron spectroscopy (E
Using SCA), the amount of oxygen bound to the surface of the protective film in the exposure step is calculated based on the following equation. Oxygen amount (%) = (01s peak area) / (total peak area) * 100 The surface activity of the protective film is evaluated based on the oxygen amount.

When a reactive gas such as N ₂ gas is used as an etching gas, it is considered that the reactive gas is bonded to dangling bonds on the surface of the carbon protective film. The surface activity of the protective film can also be evaluated by calculating the amount of the reactive gas component (for example, nitrogen) on the film surface using ESCA in the same manner as the above oxygen amount.

When etching is performed, the conditions such as the power applied to the disk D, the etching time, and the internal pressure of the chamber 20 are adjusted so that the amount of oxygen in the protective film measured using ESCA is 2.9 to 12%. (Preferably 2.9 to 9.4
%, More preferably 2.9 to 6.3%). If the amount of oxygen is less than the above range, the activity of the surface of the protective film is reduced, the bonding strength between the protective film and the lubricating film is reduced, and the fly stiction characteristics are undesirably reduced. When the oxygen amount exceeds the above range, the activity of the protective film surface becomes too high, the affinity for the lubricant becomes excessive, the thickness of the surface layer portion of the lubricating film decreases, and the fluidity of the surface layer decreases. The surface friction coefficient increases. For this reason, the CSS characteristics of the obtained magnetic recording medium deteriorate.

In etching, the above ESCA
Is from 5.0 to 16 in the protective film measured using
The etching conditions can be set so as to be 5% (preferably 5.0 to 12.4%, more preferably 5.0 to 9.4%). If the amount of nitrogen is less than the above range, the activity of the surface of the protective film is reduced, the bonding strength between the protective film and the lubricating film is reduced, and the fly stiction characteristics are undesirably reduced. When the nitrogen amount exceeds the above range, the activity of the protective film surface becomes too high, the affinity for the lubricant becomes excessive, the thickness of the surface layer of the lubricating film decreases, and the fluidity of the surface layer decreases. The surface friction coefficient increases. Therefore, C of the obtained magnetic recording medium is
SS characteristics deteriorate.

Next, a lubricant such as a fomblin lubricant or perfluoropolyether is applied on the protective film by a dipping method or the like to form a lubricant film, thereby obtaining a magnetic recording medium. The lubricating film formed on the protective film is firmly bonded to the surface of the protective film. This is for the following reason.
The lubricant is usually made of a compound containing a hydroxyl group. Further, as described above, the surface of the protective film is in a state of being chemically highly active. For this reason, on the surface of the protective film, the hydroxyl group in the lubricant becomes C =
A strong bond to the protective film by a hydrogen bond to a bond such as O, COC, C = N, or C フ ァ ン N, or a Van der Waals bond to a bond such as CＣC or C≡C having a π electron. I do. For this reason, the lubricating film is strongly bonded to the surface of the protective film.

FIG. 3 shows an example of a magnetic recording medium manufactured by the above-described manufacturing method. In the magnetic recording medium of this example, a non-magnetic base film 31, a magnetic film 32, and a carbon protective film 3 are formed on a non-magnetic substrate S.
3. A lubricating film 34 is sequentially formed.

In the manufacturing method of the present embodiment, prior to the formation of the lubricating film, the surface of the carbon protective film is etched by using the plasma generated from the etching gas. It can be in a state where it is easy to be combined with. In addition, impurities adhered to the surface of the protective film are removed from the protective film, so that it is possible to prevent deterioration of applicability of the lubricant to the protective film due to the surface impurities. Therefore, the bonding strength between the protective film and the lubricating film is increased,
Even when the magnetic recording medium is rotated for a long time with the head floating above the magnetic recording medium, a part of the lubricating film is prevented from separating from the other parts and adhering to the head, and a gap between the head and the medium is prevented. Friction coefficient can be kept low and fly stiction characteristics can be improved.

By using a plasma CVD apparatus 1 and an etching apparatus 2 which are connected so that the disk D in the plasma CVD apparatus 1 can be transferred into the etching apparatus 2 without exposing the disk D to the outside air, It is possible to prevent external air-derived impurities from adhering to the surface of the protective film, and to prevent a decrease in bonding strength between the protective film and the lubricating film due to the impurities.

In the magnetic recording medium manufactured by the above manufacturing method, the amount of oxygen on the surface of the carbon protective film measured by using ESCA can be set to 2.9 to 12% by etching. As a result, the surface of the protective film is brought into a state where the activity is high and the lubricant is likely to be firmly bonded, the bonding force between the protective film and the lubricant film is increased, and the fly stiction characteristics can be improved. The same effect can be obtained even when the amount of nitrogen on the surface of the carbon protective film measured by using ESCA is set to 5.0 to 16.5% by etching.

Further, in the present invention, an etching apparatus 3 shown in FIG. This apparatus differs from the etching apparatus 2 in that coils 41 and 42 for generating a magnetic field in the chamber 20 are provided on both outer surfaces of the chamber 20. When this apparatus is used, the coil 41,
Since the plasma in the chamber 20 is collected around the disk D by the magnetic field generated by 42, the etching efficiency can be improved.

[0044]

EXAMPLES (Test Examples 1 to 19) NiP-plated aluminum alloy substrate (95 mm in diameter, 0.8 mm in thickness)
Is subjected to mechanical texture processing, and the surface average roughness Ra
Was set to 6 °, and a DC magnetron sputtering apparatus (3010 manufactured by Anelva) was used to coat Cr on both surfaces of the substrate S.
A non-magnetic underlayer 31 made of an alloy and a magnetic film 32 made of a Co alloy were sequentially formed to obtain a disk D. This disk D is carried into the chamber 10 of the plasma CVD apparatus 1 and a mixed gas of toluene and hydrogen (toluene: hydrogen =
1:10 (volume ratio)) was supplied into the chamber 10 as a source gas. At the same time, 800 W high frequency power (frequency 1
(3.56 MHz) is applied to the electrode 11 to generate plasma, and the carbon protective film 3 having a thickness of 50 °
3 was formed. The temperature of the disk D and the film formation rate during the formation of the protective film were set to 170 ° C. and 400 ° / min, respectively.

Next, the disk D having the carbon protective film 33 formed thereon was carried into the chamber 20 of the etching apparatus 2 and supplied into the chamber 20 using Ar as an etching gas. The etching gas flow rate was 200 sccm. At the same time, high-frequency power (frequency 13.56 MHz) was applied to the disk D to generate plasma, and etching was performed on the surface of the carbon protective film on both surfaces of the disk D. Table 1 shows the high-frequency power (W) applied to the disk D during the etching, the application time (second), and the internal pressure (Pa) of the chamber 20.

After exposing the etched disk D to the atmosphere, an ESCA apparatus (Specs, Sage1)
Table 1 also shows the results obtained by measuring the amount of oxygen on the surface of the protective film 33 using (00) based on the following equation. Oxygen content (%) = (01s peak area) / (total peak area) * 100 The device specifications and measurement conditions are as follows. Anode: made of aluminum Spot size: 2-3 mm Method for determining area: fitting method (C: Gaussian fitting, N, O; Gaussian + Lorentz fitting)

Further, a Raman spectroscopic analyzer (Jobin-
Analysis of the carbon protective film 33 by Raman spectroscopy (light source: Ar laser, wavelength: 514.5 nm, output: 100 mW, exposure time: 10 seconds, method for determining area: Gaussian fitting) using Yvon Corporation. The results are shown in Table 1.

Further, the magnetic recording medium having a lubricating film 34 formed on the carbon protective film 33 by a dipping method,
Table 1 also shows the results of measuring the ded Ratio. The measuring method is as follows. The magnetic recording medium is immersed in a solvent (AK225 manufactured by Asahi Glass Co., Ltd.) for 15 minutes and then taken out. The ratio (%) of the thickness of the lubricating film 34 after the operation to the thickness of the lubricating film 34 before the operation is determined. Calculated. In addition, the film thickness of the lubricating film 34 was measured by using FT-IR at a position having a radius of 20 mm. Table 1 also shows the results of measuring the water contact angle (degree) on the surface of the protective film 33.

[0049]

[Table 1]

(Test Examples 20 to 37) A magnetic recording medium was manufactured in the same manner as in Test Examples 1 to 19 except that N ₂ was used as an etching gas. At this time, the amount of nitrogen on the surface of the protective film 33 was tested by ESCA. It measured similarly to Examples 1-19. Raman spectroscopy and Bo were performed in the same manner as in Test Examples 1 to 19.
Table 2 also shows the results of the nded Ratio measurement.

[0051]

[Table 2]

According to Tables 1 and 2, the carbon protective film 33
When the surface is not etched (Test Examples 1, 20)
When performing etching as compared to (Test Examples 2 to 19,
21 to 37) show that the Bonded Ratio is high. Therefore, it is understood that the separation of the lubricant hardly occurs and a magnetic recording medium having excellent fly stiction characteristics was obtained. In particular, those having an oxygen content of 2.9 to 12% on the surface of the protective film measured by ESCA,
It can be seen that excellent fly stiction characteristics were obtained when the nitrogen content of the protective film surface was 5.0 to 16.5%.

[0053]

As described above, according to the present invention,
Prior to the formation of the lubricating film, the surface of the carbon protective film is etched using plasma generated from an etching gas, so that the surface of the protective film is in a state where the activity is high and the lubricant is easily and firmly bonded, and the protective film is formed. Impurities attached to the surface can be removed from the protective film. Therefore, the joining force between the protective film and the lubricating film can be increased, and the fly stiction characteristics of the magnetic recording medium can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an etching apparatus used to carry out an embodiment of a method for manufacturing a magnetic recording medium of the present invention.

FIG. 2 is a configuration diagram showing a plasma CVD apparatus used for carrying out one embodiment of a method for manufacturing a magnetic recording medium of the present invention.

FIG. 3 is a sectional view showing an example of the magnetic recording medium of the present invention.

FIG. 4 is a configuration diagram showing an etching apparatus used for carrying out another embodiment of the method for manufacturing a magnetic recording medium of the present invention.

[Explanation of symbols]

1 ... plasma CVD device, 2, 3 ... etching device,
31: Non-magnetic base film, 32: Magnetic film, 33: Carbon protective film, 34: Lubricating film, D: Disk, S: Non-magnetic substrate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Riku Wenqiang 5-1, Hachiman Kaigan-dori, Ichihara-shi, Chiba Prefecture Inside HD Research & Development Center, Showa Denko KK (72) Inventor Hiroshi Daio Yawata-kaigandori, Ichihara-shi, Chiba F-term in the HD Research and Development Center, Showa Denko KK (Reference) 5D006 AA02 AA05 AA06 DA03 EA03 FA05 FA06 5D112 AA07 AA11 AA24 BC05 GA02 GA20 GA22

Claims (6)

[Claims] 1. A method for manufacturing a magnetic recording medium, comprising: forming a carbon protective film by a plasma CVD method on a disk having a nonmagnetic base film and a magnetic film formed on a nonmagnetic substrate; and forming a lubricating film thereon. A method for manufacturing a magnetic recording medium, comprising: etching a surface of a carbon protective film using plasma generated from an etching gas before forming a lubricating film. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein, when etching the surface of the carbon protective film, plasma is generated by applying high-frequency power to the disk on which the carbon protective film is formed. . 3. A magnetic recording medium manufactured by the method for manufacturing a magnetic recording medium according to claim 1, wherein X
A magnetic recording medium characterized in that the amount of oxygen on the surface of the carbon protective film measured by linear photoelectron spectroscopy is 2.9 to 12%. 4. The magnetic recording medium according to claim 3, wherein the B / A value of the carbon protective film measured by Raman spectroscopy is from 1.22 to 1.65. 5. A magnetic recording medium manufactured by the method for manufacturing a magnetic recording medium according to claim 1, wherein X
A magnetic recording medium, wherein the amount of nitrogen on the surface of the carbon protective film measured by linear photoelectron spectroscopy is 5.0 to 16.5%. 6. The magnetic recording medium according to claim 5, wherein the B / A value of the carbon protective film measured by Raman spectroscopy is 1.21 to 1.52.