JP2002050032A - Magnetic recording medium, method for producing the same and method for inspecting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for inspecting the lowness of adhesion of an extraneous substance and to provide a magnetic recording medium to which an extraneous substance is less liable to adhere and a method for producing the medium. SOLUTION: A carbon-base protective film is formed on a disk obtained by forming at least a nonmagnetic underlayer and a magnetic layer on a nonmagnetic substrate and the adhesive property of an extraneous substance to the surface of the protective film of the resulting magnetic recording medium is inspected. In this inspection method, the magnetic recording medium is allowed to stand in an atmosphere of a gas for inspection and the amount of the gas and/or a gas component-containing formed compound extracted by a solvent for inspection is compared with a previously set reference value. The magnetic recording medium is produced in such a way that the amount of the extract is adjusted to the reference value or above in the inspection method.

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 for manufacturing the same and a method for inspecting the same, and more particularly to a magnetic recording medium having good durability, a method for manufacturing the same and a method for inspecting the same.

[0002]

2. Description of the Related Art A hard disk drive, which is one type of magnetic recording / reproducing apparatus, includes a magnetic recording medium and a magnetic head for recording / reproducing information on / from the magnetic recording medium, and its recording density is currently increasing at an annual rate of 60%. It is said that the trend will continue in the future. Development of a magnetic recording head suitable for a high recording density and development of a magnetic recording medium have been advanced.

A magnetic recording medium used for a magnetic recording / reproducing apparatus or the like basically has the following configuration. A Cr alloy such as Cr or CrW or CrMo is formed as a non-magnetic underlayer for crystal orientation of a Co alloy layer by a sputtering method or the like on a substrate that is Ni-P plated or a glass substrate on an Al alloy, A Co alloy thin film is formed thereon as a magnetic layer, and carbon or the like is formed as a protective film, and a lubricant such as perfluoropolyether is applied as necessary.

In recent years, it has been required to increase the recording density of a magnetic recording medium, and a magnetic recording medium capable of reducing a spacing loss (the distance between a magnetic recording head and a magnetic layer) has been desired. In order to reduce the spacing loss, it has been studied to make the carbon protective film thinner and to further reduce the flying height of the magnetic recording head. As a method of forming the carbon protective film, there are a sputtering method and a plasma CVD method.
The adoption of the law is being considered.

[0005]

One of the evaluations of durability is a fly stiction characteristic. The fly stiction characteristic refers to a CSS (Cont.) After a magnetic recording medium is rotated and a magnetic head is floated for a predetermined time.
Act-Start-Stop) is a characteristic represented by a stiction value. When the fly stiction characteristics are reduced, the flight stability of the head is reduced, and inconveniences such as a head crash due to contact between the protective film and the head are likely to occur. In particular, since a medium corresponding to a high recording density is used in a state where the flying height of the head is further reduced, a medium having better fly stiction characteristics is required.

[0006] However, the magnetic recording medium manufactured by the above-described conventional technique sometimes has a reduced fly stiction characteristic. One of the causes is that the adhered substances adhere to the surface of the magnetic recording medium in the above-described magnetic recording / reproducing apparatus, and adhere to the magnetic head during long-term use, so that fly stiction characteristics are reduced. It is conceivable that it will decrease. One of the deposits may be a compound containing a gas component generated in the magnetic recording / reproducing device or a compound in which the gas component has reacted with an ionic substance such as a metal in the device. For example, a plastic material such as a resin or a photocurable resin is used for various members used in the magnetic recording / reproducing apparatus. From these materials, compounds such as a plasticizer such as a phthalic acid ester and a photoreaction initiator are generated as impurity gases. Further, a lubricant used for the pins of the connector portion also exists as an impurity gas in the magnetic recording / reproducing apparatus. The magnetic recording / reproducing device has a structure in which the inside is isolated from the outside air to maintain the cleanliness.Therefore, the gas generated inside will remain in the device in some form, and a part of the gas will It is considered to be. When the deposits adhere to the head, there is a possibility that actual writing on the magnetic recording medium or reading from the magnetic recording medium becomes insufficient.

Therefore, there is a need for a magnetic recording medium to which deposits are less likely to adhere in a high recording density magnetic recording / reproducing apparatus. Further, at present, there is no method for inspecting the difficulty of adhesion of these deposits on a magnetic recording medium.

The present invention has been made in view of these circumstances, and provides a method for inspecting the difficulty of adhering matter, a magnetic recording medium to which adhering matter is less likely to adhere, a method of manufacturing the same, and a method of manufacturing the same. It is an object of the present invention to provide a magnetic recording / reproducing device using the same.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the gas generated in the magnetic recording / reproducing apparatus, the deposits adhering on the carbon protective film of the magnetic recording medium and the carbon protective film are not affected. The characteristics were examined, and the present invention was reached based on the findings. 1) A first invention for solving the above-mentioned problem is a magnetic recording medium in which a protective film containing carbon as a main component is formed on a non-magnetic substrate on which at least a non-magnetic underlayer and a magnetic layer are formed. In the method for inspecting the adhesion characteristics of the deposit on the surface of the protective film, the method further comprises the step of leaving the magnetic recording medium in an atmosphere of an inspection gas and then extracting the inspection gas component and / or the inspection gas component extracted with an inspection solvent. A method for inspecting a magnetic recording medium, wherein it is determined that the extraction amount of the compound component formed in step (a) is equal to or greater than a predetermined reference value. 2) A second invention for solving the above-mentioned problem is a test gas for generating a gas generated in a magnetic recording / reproducing apparatus including a magnetic recording medium and a magnetic head for recording / reproducing information on / from the magnetic recording medium. The inspection method according to 1), wherein the inspection method comprises a component. 3) A third invention for solving the above-mentioned problem is that the test gas components are a siloxane-based gas, an acrylic acid-based gas, a vaporized melamine, a vaporized lubricant, a vaporized higher fatty acid, a vaporized phthalate, a vaporized phthalate, The inspection method according to 1) or 2), wherein one or a combination of two or more dioctyl phthalates is used. 4) A fourth invention for solving the above problem is characterized in that the inspection gas component is a gas component generated from a member used inside the magnetic recording reproduction apparatus 1) to 3).
The inspection method according to any one of the above. 5) A fifth invention for solving the above-mentioned problem is characterized in that the test solvent is one or a combination of two or more selected from methanol, ethanol, isopropyl alcohol, and water. The inspection method according to any one of 4). 6) According to a sixth aspect of the invention for solving the above-mentioned problem, the reference value when the extraction component is melamine is 0.06 [μg / 10
0 cm ² ]. The inspection method according to any one of 1) to 5) above. 7) A seventh aspect of the present invention for solving the above-mentioned problem is a magnetic recording medium in which at least a nonmagnetic underlayer and a magnetic layer are formed on a nonmagnetic substrate, and a protective film containing carbon as a main component is formed. A magnetic recording medium wherein the amount of the test gas component extracted from the test solvent after the magnetic recording medium is left in the test gas atmosphere and / or the compound component formed including the test gas component is equal to or more than a reference value. It is a recording medium. 8) According to an eighth aspect of the present invention for solving the above-mentioned problem, the reference value when the extraction component is melamine is 0.06 [μg / 10
0 cm ² ]. 9) A ninth invention for solving the above-mentioned problem is characterized in that a peak intensity value derived from a carbon-hydrogen bond in an infrared absorption curve of a surface of a protective film containing carbon as a main component is 0.055 or less. The magnetic recording medium according to any one of 7) and 8). 10) A tenth invention for solving the above-mentioned problem is that the protective film mainly containing carbon has a nitrogen-carbon ratio of 5 to 40 at.
%, The magnetic recording medium according to any one of 7) to 9). 11) An eleventh invention for solving the above problems is characterized in that the value of Id / Ig on the surface of the protective film containing carbon as a main component is 3.5 or less. 2. A magnetic recording medium according to claim 1. 12) A twelfth invention for solving the above-mentioned problem is a magnetic recording medium in which a protective film containing carbon as a main component is formed on a disk on which at least a nonmagnetic underlayer and a magnetic layer are formed on a nonmagnetic substrate. In the manufacturing method, the extraction amount of the test gas component and / or the compound component formed including the test gas component extracted with the test solvent after leaving the magnetic recording medium in the test gas atmosphere is a reference value. A method of manufacturing a magnetic recording medium characterized by the above. 13) A thirteenth invention for solving the above problem is characterized in that the method of forming a protective film containing carbon as a main component includes a sputtering method of forming a protective film while applying a bias to a disk. (12) A method for manufacturing a magnetic recording medium according to (12). 14) A fourteenth invention for solving the above-mentioned problem is characterized in that the method for forming a protective film containing carbon as a main component includes a plasma CVD method using a reaction gas containing hydrocarbon as a raw material. A method for manufacturing a magnetic recording medium according to 12). 15) According to a fifteenth invention for solving the above-mentioned problems, a method of forming a protective film containing carbon as a main component is performed by a plasma CVD method using a reactive gas containing hydrocarbon as a raw material, and a bias is applied to a disk. Characterized by including a forming step by a sputtering method for forming a protective film while forming the protective film.
A method for manufacturing a magnetic recording medium according to 2). 16) A sixteenth invention for solving the above problems includes a magnetic recording medium, and a magnetic head for recording and reproducing information on and from the magnetic recording medium, wherein the magnetic recording medium is any one of 7) to 11). A magnetic recording / reproducing apparatus characterized in that the magnetic recording medium is the magnetic recording medium described in the section. In this specification, atomic% is also described as at%. In the present specification, 1 nm = 10 °.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the inspection method of the present invention will be described. First, the outline of the inspection method of the present invention will be described. In the inspection method of the present invention, the surface of a magnetic recording medium, which is a sample on which a protective film containing carbon as a main component is formed, is exposed to an inspection gas by leaving the magnetic recording medium, which is a sample, in an atmosphere of an inspection gas. A step of immersing the exposed magnetic recording medium in a test solvent and extracting the same, and a compound formed containing the test gas component amount and / or test gas extracted in the test solvent after immersion. The method includes a step of measuring the amount of the extracted amount and a step of determining that the amount of the extracted amount is equal to or greater than a predetermined reference value.

Conventionally, a magnetic recording medium having a deposit on the surface of a protective film is immersed in a solvent, and then the amount of extraction into the solvent is measured. However, it was considered that the magnetic recording medium had a small amount of deposits and thus did not easily adhere to the deposits. Conversely, the magnetic recording medium of the present invention has a large amount of a test gas component and / or a compound component formed containing a test gas, which is a component that can become a deposit after exposure, extracted into a solvent, for example, It is assumed that it is higher than the reference value.

Here, it is presumed that the following mechanism can determine the amount of surface deposits generated from the amount of extraction. FIG. 2 shows the amount of deposits on the surface of the protective film of the magnetic recording medium when the total amount of incoming gas is changed, for example, when the exposure time is changed. Range of e in the magnetic recording medium E in the figure,
The range of f of the magnetic recording medium F means that no deposits adhere to the surface even if the total amount of incoming gas increases. In other words, this indicates that the magnetic recording medium F is less likely to deposit on the surface with respect to the total amount of gas that has flown than E. Here, the inventor considered that the range of e and the range of f are states in which the flying gas does not adhere to the surface of the protective film but is adsorbed inside the protective film. In other words, the inventor considered that if the total amount of gas is larger than the amount that can be adsorbed inside, it will adhere as a precipitate to the surface. Therefore, since the magnetic recording medium F has a larger amount that can be adsorbed inside the protective film than the magnetic recording medium E, it is less likely that deposits will adhere to the surface. here,
The amount of extraction measured according to the present invention can be the amount of internal adsorption. The magnetic recording medium of the present invention in which the amount of extraction is equal to or more than the reference value is a magnetic recording medium in which precipitates are unlikely to adhere to the surface because the amount of internal adsorption is sufficiently large. For example, when the magnetic recording medium A is used as a defective sample to which precipitates are adhered and the extraction amount measured according to the present invention is used as a reference value, the magnetic recording medium of the present invention has a large internal adsorption amount because the extraction amount is equal to or more than the reference value. As a result, the magnetic recording medium does not easily cause the deposit to adhere to the surface.

Hereinafter, a specific inspection procedure will be described. An example of a magnetic recording medium used as a sample to be inspected is, for example, the one shown in FIG. The magnetic recording medium of this example has a non-magnetic underlayer 1, a magnetic layer 2,
The carbon protective film 3 and the lubricating layer 4 are sequentially formed.

First, a sample is left in an atmosphere of a test gas, and the surface is exposed to the gas. For example, introducing inspection gas,
The magnetic recording medium is left inside a sealed container having a function of discharging, and an inspection gas is introduced into the container. For example, it is preferable to use a magnetic recording / reproducing device as a sealed container because a magnetic recording medium can be attached to a spindle in the device. Furthermore, it is preferable to rotate the spindle similarly to the magnetic recording / reproducing apparatus actually used, since the exposure can be performed in a state close to the actual use state. The number of rotations can be any of the range of 4200 to 15000 [rpm].

The concentration of the test gas is, for example, 3.8 [μg
/ Magnetic recording / reproducing apparatus internal space volume] (in terms of siloxane oligomer). Alternatively, the concentration of the test gas can be, for example, 15 [ng / cm ³ ] (in terms of siloxane oligomer). A higher concentration is preferred from the viewpoint of accelerating the test.

The leaving time can be, for example, 24 hours. It is preferable that the standing time is sufficiently long from the viewpoint of sufficiently adsorbing the inside.

The temperature at the time of standing can be, for example, the ambient temperature of the installation atmosphere of the magnetic recording / reproducing apparatus. A higher temperature is preferable from the viewpoint of accelerating the test.

The pressure during the standing can be, for example, normal pressure. Pressurization is preferred from the viewpoint of accelerating the test.

When the concentration is low, it is possible to adjust the standing time, the standing temperature and the like appropriately (for example, a standing time of 72 hours and a standing temperature of 40 ° C.) to sufficiently adsorb the inside.

Here, the test gas may be a gas generated in the magnetic recording device. In addition, it can be a component that forms a compound that forms a substance attached to the surface of the magnetic recording medium. This is preferable because the possibility of exposure when the magnetic recording medium is actually used in the magnetic recording apparatus can be reproduced. The test gas is, for example,
Any one selected from siloxane-based gas, acrylic acid-based gas, stearic acid gas, vaporized melamine, vaporized lubricant, vaporized higher fatty acid (for example, having 10 or more carbon atoms), vaporized phthalate, and vaporized dioctyl phthalate Alternatively, a combination of two or more is preferable. In the combination, it is preferable to set the combination close to the actual use state, since the condition becomes closer to the actual use state, and the inspection is performed under the condition closer to the actual use state. Instead of introducing a gas, a member that generates a gas, for example, an adhesive tape, a resin, a film, or the like can be left in the container together with the magnetic recording medium.
For example, it is preferable to use a magnetic recording / reproducing apparatus as a container and leave a member actually used inside together with a magnetic recording medium attached to a spindle, since the operation is performed under conditions close to actual use. It is preferable to rotate the spindle because the operation is performed under conditions closer to actual use conditions. If the gas concentration is unknown, as in the case of using a member as a gas generation source, the leaving time, leaving temperature, etc. are appropriately adjusted (for example, leaving time 72 hours, leaving temperature 4
(0 ° C.), and sufficiently adsorbed inside.

Next, the exposed sample is immersed in a test solvent as described below, and an extraction process is performed using a test gas and / or a compound component containing the test gas component as a component to be extracted. .

The extraction solvent may be any as long as it can dissolve the components to be extracted. For example, it is preferable to use one or a combination of two or more selected from methanol, ethanol, isopropyl alcohol, and water.

The amount of the solvent can be, for example, 30 [ml / magnetic recording medium]. It is preferable to increase the amount in terms of extraction efficiency.

The extraction time can be, for example, one hour. When the solvent extraction ability is low, the longer the standing time, the better.

The temperature at the time of extraction can be appropriately set depending on the type of the test solvent used, and may be, for example, 80 ° C. The higher the temperature, the better from the viewpoint of extraction efficiency.

Next, the components to be extracted extracted in the test solvent are quantitatively measured by a general quantitative measuring method using, for example, GC-MS.

The reference value is determined, for example, as follows. The reference value can be determined based on the extraction amount value measured by the above method using a magnetic recording medium having the durability required when actually used in a magnetic recording / reproducing apparatus as a sample. Conversely, the reference value can be determined based on the amount of extraction measured by the above method using a magnetic recording medium having poor durability as a sample. For example, a reference value is determined based on the amount of extraction measured by the above method using a magnetic recording medium that failed in the fly stiction test or a magnetic recording medium on which the surface was observed after exposure as a sample. can do. The reference value may be a measured extraction value multiplied by a safety factor. For example, if the extraction amount using the defective magnetic recording medium is X, the reference value can be X. The reference value can be set to (X × α) using α as the safety coefficient.

The magnetic recording medium is inspected by comparing the extraction amount of the sample measured by the above method with the reference value determined by the above method and determining that the extraction amount is equal to or more than the reference value.

In the conventional method, a sample having a large amount of extraction or a sample having a reference value or more is determined to be defective. Therefore, a sample having a large amount of internal adsorption that does not adhere to the surface may be regarded as defective. According to the inspection method of the present invention, since the amount of extraction after exposure is equal to or more than the reference value, it is possible to appropriately determine a substance having a large internal adsorption amount. As a result, it is possible to appropriately determine the property of the magnetic recording medium that is difficult to adhere.

An embodiment of the magnetic recording medium of the present invention will be described. As an example of the magnetic recording medium of the present invention, for example, the one shown in FIG. 1 can be mentioned. The magnetic recording medium of this example has a non-magnetic underlayer 1, a magnetic layer 2, a protective film 3 mainly composed of carbon formed on a non-magnetic substrate S, and a lubricating film 4 formed thereon.

The non-magnetic substrate S is an aluminum alloy substrate having a NiP plating film generally used as a substrate for a magnetic recording medium (hereinafter, also referred to as "NiP plated Al substrate"), a glass substrate, a ceramic substrate, a flexible substrate. Or a substrate obtained by depositing NiP or another alloy on these substrates by plating or sputtering.

The average roughness Ra of the surface of the non-magnetic substrate S is 1 to
It is preferable that the angle be 20 ° (preferably 1 to 15 °).

As the nonmagnetic underlayer 1, a conventionally known nonmagnetic underlayer such as Cr, Ti, Ni, Si, Ta,
Any single-component film selected from W or a film made of an alloy containing any of these as a main component and containing other elements within a range that does not impair the crystallinity thereof can be used. The function of the non-magnetic underlayer 1 is as follows.
Is to control the crystal orientation of
Or Cr, Mo, W, V, Ti, Nb,
It is preferable to use a material containing one or more selected from Si. When using the above material, the composition is preferably CrzY. Here, Y is one or more selected from Mo, W, V, Ti, Nb, and Si. Y content (z) is 2
It is preferable that the content be 0 at% or less. More preferably, the content is 10 at% or less. The magnetic recording medium having this content of 20 at% or less has a C content formed on the non-magnetic underlayer 1.
The orientation of the magnetic layer 2 made of an o-alloy is improved, and as a result, the coercive force and noise characteristics are improved, and the magnetic layer 2 is more suitable for high recording density. In the present specification, the “main component” in the alloy means that the content exceeds 50 at%.

In some cases, the crystal grain size of the nonmagnetic underlayer 1 affects the crystal grain size of the magnetic layer 2 made of a Co alloy. In the case where the crystal grain size of the nonmagnetic underlayer 1 is reduced, the material of the nonmagnetic underlayer 1 can be obtained by adding B, Zr, Ta, or the like to Cr or a Cr alloy.

The thickness of the nonmagnetic underlayer 1 is not limited as long as a predetermined coercive force can be obtained. This thickness is preferably in the range of 100 to 1000 °, and 15
More preferably, it is 0-700 °. Non-magnetic underlayer 1
The magnetic recording medium having a film thickness in the above-mentioned range has been confirmed to have the effect of improving the coercive force and the effect of improving the SNR.

Further, the non-magnetic underlayer 1 may have a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, the materials may be formed by laminating the same or different compositions among those described above. For example, a CrMo alloy layer (Mo content of 10 at% or less) may be laminated on the Cr layer.

The magnetic layer 2 made of a Co alloy has a composition of Co / Cr based, Co / Cr / Ta based,
/ Cr / Pt / Co / Cr / Pt / Ta alloys.

The coercive force of the magnetic recording medium of the present invention is 3
000 [Oersted], preferably 3500 [Oersted] or more.

The film thickness of the magnetic layer 2 made of a Co alloy is Brd (product of residual magnetization and film thickness [G
μm]), the film thickness can provide a predetermined recording / reproducing signal output within a range of 30 to 100 [G μm].

In order to improve the orientation of the Co alloy and obtain a high coercive force, a non-magnetic intermediate layer can be provided between the non-magnetic underlayer 1 and the magnetic layer 2. For example, a CoCr alloy having a thickness of 25 ° or less (Cr content 50 at% or less)
Layers can be formed.

The carbon protective film 3 is made of a material containing carbon as a main component. The carbon protective film 3 has an extraction amount of the test gas component and / or a compound component formed containing the test gas component which is extracted with the test solvent after being left in the test gas atmosphere, and the amount of extraction is equal to or greater than a reference value. . Preferably, the extract component is melamine. The reference value in that case is 0.06
[Μg / 100 cm ² ] (preferably 0.12 [μg /
100 cm ² ]. More preferably, 0.24 [μg / 10
0 cm ² ]). Melamine was used as an extraction component because it is a main impurity gas that causes precipitation in a magnetic recording / reproducing apparatus. The reason for setting the amount of melamine to be in the above range is as follows. If the value is within the above range, the amount of the impurity gas that can be adsorbed inside the carbon protective film 3 increases, so that the deposit hardly adheres to the carbon protective film 3 on the surface of the magnetic recording medium. The amount of extraction can be determined by the method described above.

The protective film 3 may contain nitrogen as another component. The content thereof is such that the nitrogen-carbon ratio measured by the ESCA measurement method is 5 to 40% (more preferably 5 to 40%).
25%. More preferably, 13 to 25%. ) Is preferred. This is because a film containing nitrogen is a denser and harder film.

In this case, the carbon protective film preferably has a nitrogen concentration of 2 at% or less at a position near the surface in contact with the magnetic layer. Outside of this range,
This is because the magnetostatic properties of the magnetic layer are degraded and the coercive force is reduced, so that the magnetic recording medium is not suitable for a low flying height. The nitrogen concentration in the magnetic layer is, for example, SIMS
It can be determined by analysis. The vicinity can be, for example, a position at the boundary between the magnetic layer and the protective film where the Co concentration is 5% of the concentration corresponding to the magnetic layer.

A dense and hard protective film is preferable because it can suppress the generation of abrasion powder and the generation of Ni corrosion which induce the adhesion of deposits. Here, Ni corrosion means that Ni appears on the surface of the magnetic recording medium by diffusion or the like from the Ni-P plating layer on the substrate, and is evaluated by, for example, extracting the Ni appearing on the surface and measuring the amount thereof. it can.

The carbon protective film 3 preferably has a peak intensity value derived from a carbon-hydrogen bond by the FTIR method of 0.055 or less (more preferably 0.05 or less, further preferably 0.04 or less). This is because the protective film containing carbon as the main component in this range has a strong bonding force with the lubricant of the protective film. This is because a material having a strong bonding force can stably cover the surface of the protective film with a lubricant, so that the adhesion of deposits can be suppressed.

The peak intensity derived from the carbon-hydrogen bond by the FTIR method is measured, for example, as follows. The peak intensity value of an absorption curve of a CF bond (carbon-fluorine bond) measured when a perfluoropolyether-based lubricant is applied on a disk at a film thickness of 2 [nm] (for example, 1120 to 120 nm).
Peak intensity values appearing in the range of 1350 cm ^-1 . ) Is 0.
Prepare an FTIR with a sensitivity of 008. From the measurement of the infrared absorption curve of the surface of the magnetic recording medium before forming the protective film mainly composed of carbon and the measurement of the infrared absorption curve of the surface of the magnetic recording medium after forming the protective film Then, an infrared absorption curve of a protective film containing carbon as a main component (hereinafter also referred to as “a protective film infrared absorption curve containing carbon as a main component”) is obtained. Next, 2800 cm ^{-1 to} 3100 cm
^The calculated peak area of the infrared absorption curve appearing in the range of ^-1 is defined as a peak intensity value derived from a carbon-hydrogen bond.
Here, the peak intensity value is the amount of absorption.

The protective film 3 is made of Id / Ig by Raman spectroscopy.
Is preferably 3.5 or less (more preferably 3.0 or less, further preferably 2.5 or less). This is because the protective film containing carbon as a main component in this range is dense and hard. The value of Id / Ig means that the measured Raman spectrum is separated into a distribution having a peak near 1500 cm ^-1 (G band) and a distribution having a peak near 1400 cm ^-1 (D band), and integration of the intensity of the G band. The ratio was determined by setting the value to Ig and the integrated value of the intensity of the D band to Id.

The surface of the protective film preferably has a water contact angle of 80 degrees or less (more preferably 75 degrees or less). This is because the protective film having a water contact angle of 80 degrees or less has a sufficient bonding force with the lubricant, so that the lubricant does not easily adhere to the magnetic head.

The thickness of the carbon protective film 3 can be 90 ° or less. 75 ° or less, more preferably 50 °
Å It is preferable that it is not more than. This is because the spacing loss can be further suppressed and the output of the reproduction signal can be increased.

The lubricating film 4 is formed by applying a lubricant. Lubricants include Fomblin lubricant (Audimont), Galden lubricant (Audimont),
It may contain any one selected from a demnum-based lubricant (manufactured by Daikin Industries, Ltd.) and a Krytox-based lubricant (manufactured by DuPont).

The above effect can be obtained more favorably when the type of the lubricant is a Fomblin lubricant. This is because both ends of the molecular chain of the Fomblin lubricant are polar functional groups, and the groups are easily adsorbed to the active site of the carbon protective film 3.

The thickness of the lubricating film can be 5 to 30 °. More preferably, it is 10 to 25 °. Within this range, appropriate lubricity is obtained, and an excessive amount of lubricant does not adhere to the head, which is preferable.

In the magnetic recording medium of the present invention, extraction of the test gas component and / or the compound component formed containing the test gas component, which is extracted with the test solvent after being left in the test gas atmosphere. Since the amount is equal to or more than the reference value, the protective film mainly composed of carbon on the surface of the magnetic recording medium is hardly adhered to by deposits. When melamine is used as the extraction component, the reference value is 0.06 [μg / 100 cm ² ] (more preferably 0.12 [μg / 100 cm ² ], and still more preferably 0.24 [μg / 100 cm ² ]). Is preferred. As a result, in the magnetic recording medium of the present invention, it is difficult for the magnetic recording medium to adhere to the head even when the head is used with a reduced flying height. This results in a magnetic recording medium whose action characteristics do not deteriorate. Further, since the carbon protective film 3 preferably has a peak intensity value derived from carbon-hydrogen bonds by the FTIR method of 0.055 or less, the surface of the protective film can be stably covered with a lubricant to suppress the adhesion of deposits. it can.

Preferably, the carbon protective film 3 is made of E
Since the nitrogen-carbon ratio measured by the SCA measurement method contains nitrogen at a content of 5 to 40%, the film is denser and harder.
The magnetic recording medium of the present invention is preferably made of carbon that is harder and thinner and has excellent sliding durability and lubricating properties, suppresses the generation of abrasion powder that induces adhesion of deposits, and suppresses the generation of Ni corrosion. The magnetic recording medium has a protective film as a main component.

Further, the distance between the head and the magnetic layer, which is the magnetic recording layer, is reduced by reducing the flying height of the head and by reducing the thickness of the protective film containing carbon as a main component. In a magnetic recording medium, spacing loss can be reduced. Therefore, the output of the reproduction signal can be increased, and the SNR (signal
o noise ratio), the magnetic recording medium of the present invention is a magnetic recording medium capable of supporting a higher recording density than a conventional magnetic recording medium.

Further, it is preferable that the coercive force is not less than 3000 [Oersted], preferably not less than 3500 [Oersted], and the surface average roughness Ra is not more than 20 °, more preferably not more than 10 °. If the coercive force is 3000 [Oersted] or more, the output of the reproduced signal can be further increased at a high recording density. When the surface average roughness is set to 20 ° or less, the flying height of the head can be further reduced. As a result, the magnetic recording medium of the present invention can support a higher recording density.

FIG. 3 shows an example of a magnetic recording and reproducing apparatus using the above magnetic recording medium. The magnetic recording / reproducing apparatus shown here comprises a magnetic recording medium 30 having the configuration shown in FIG. 1, a medium drive unit 31 for rotating and driving the magnetic recording medium 30, and a magnetic head 32 for recording / reproducing information on / from the magnetic recording medium 30.
A head drive unit 33 for moving the magnetic head 32 relative to the magnetic recording medium 30; and a recording / reproducing signal processing system 34. The recording / reproducing signal processing system 34 processes an external recording signal and sends it to the magnetic head 32,
The reproducing signal from the magnetic head 32 can be processed and sent to the outside. The magnetic head 32 used in the magnetic recording / reproducing apparatus of the present invention has an MR (magnet) using an anisotropic magnetoresistance effect (AMR) as a reproducing element.
It is possible to use a head suitable for higher recording density, which has a GMR element utilizing the giant magnetoresistance effect (GMR) as well as an element for the high recording density.

According to the magnetic recording / reproducing apparatus, the amount of the test gas component extracted from the test solvent after being left in the test gas atmosphere and / or the compound component containing the test gas component is reduced. Since the magnetic recording medium having the reference value or more is used, it is difficult for the attached matter to adhere to the surface of the magnetic recording medium. Therefore, even if the flying height of the head is reduced, the attached matter is not easily attached to the head. As a result, the flying height of the head in the apparatus can be further reduced, so that the magnetic recording / reproducing apparatus of the present invention can have a higher recording density. Further, a magnetic recording / reproducing apparatus having excellent fly stiction characteristics can be obtained.

Next, a method for manufacturing the magnetic recording medium of the present invention will be described. (Apparatus Used in Manufacturing Method) First, C used in the present invention
The VD device and the protective film reforming device will be described. FIG. 4 is a diagram showing a configuration of a plasma CVD apparatus which is a main part of a manufacturing apparatus used for carrying out one embodiment of a method for manufacturing a magnetic recording medium according to the present invention. A CVD apparatus chamber 10 for accommodating a disk D on which a protective film containing carbon as a main component is to be formed, electrodes 11, 11 installed opposite to each other in the wall surfaces on both sides of the CVD apparatus chamber 10, Power supply 1 for supplying high frequency power to the power supply 11
2, 12; a bias power supply 13 connectable to the disk D in the CVD apparatus chamber 10 when a protective film mainly composed of carbon is formed on the disk; and a carbon mainly composed of carbon to be formed on the disk D. The apparatus is provided with process gas supply sources 14 serving as a raw material of the protective film.

The supply source 1 is provided in the CVD apparatus chamber 10.
Inlet pipes 15 and 15 for introducing the process gas supplied from 4 and 14 into the CVD apparatus chamber 10 and an exhaust pipe 16 for discharging the gas in the CVD apparatus chamber 10 to the outside of the system are connected. A process gas flow control valve (not shown) is provided in each of the introduction pipes 15, and the flow rate of the gas introduced into the CVD apparatus chamber 10 is set to an arbitrary value by adjusting the gas flow rate. You can do it. The exhaust pipe 16 is provided with an exhaust amount adjusting valve 17 so that the gas pressure in the CVD apparatus chamber 10 can be set to an arbitrary value by adjusting the exhaust amount.

As the high-frequency power supplies 12, 12, it is preferable to use a power supply that can supply, for example, 50 to 1000 W of power during the formation of the protective film containing carbon as a main component and during the oxygen plasma discharge. High frequency power supply 12,
The frequency 12 is not particularly defined in terms of the operation of the present invention, but may be 13.56 MHz, for example.

As the bias power supply 13, a pulse DC power supply can be used. Alternatively, a high frequency power supply can be used.

FIG. 5 is a block diagram showing a protective film reforming apparatus used for carrying out one embodiment of the method for manufacturing a magnetic recording medium according to the present invention. The apparatus includes a chamber 20 for accommodating a disk D having a protective film mainly composed of carbon to be subjected to a protective film modification, and a high-frequency power supply 21 for supplying high-frequency power to the disk D in the chamber 20. In addition,
Reference numeral 24 indicates a matching device.

An introduction pipe 25 for introducing nitrogen gas supplied from a supply source (not shown) into the chamber is provided in the chamber 20.
And an exhaust pipe 26 for discharging gas in the chamber 20 to the outside of the system.
Is connected. The exhaust pipe 26 has a displacement control valve 2
7 is provided, and by adjusting the displacement,
The internal pressure of the chamber 20 can be set to an arbitrary value.

As the high-frequency power supply 21, it is preferable to use a power supply that can supply, for example, 50 to 1000 W of electric power during the protective film reforming process. Although the frequency of the high-frequency power supply 21 is not particularly defined in terms of the operation of the present invention,
Rf frequency, for example 13.56 MHz
Can be used.

The protective film reforming apparatus and the plasma CVD apparatus are connected to each other so that a disk in the plasma CVD apparatus can be transferred into the protective film reforming apparatus without exposing the disk to the outside air. Further, by using a plasma CVD apparatus and a protective film reforming apparatus connected so that the disk D in the plasma CVD apparatus can be transferred into the protective film reforming apparatus without being exposed to the outside air, It is possible to prevent impurities derived from outside air from adhering to the film surface, and to prevent a decrease in bonding strength between the protective film and the lubricating film due to the impurities. Further, in the present invention, in the protective film reforming apparatus, a protective film reforming apparatus in which coils for generating a magnetic field in the chamber 20 are provided on both outer surfaces of the chamber 20 may be used. When this apparatus is used, the chamber 2 is protected by a magnetic field generated by the coil during the protective film reforming process.
Since the plasma within 0 is collected around the disk D, the efficiency of the reforming process can be increased.

Next, taking the case where the above-mentioned apparatus is used as an example,
One embodiment of the method for manufacturing a magnetic recording medium of the present invention will be described.
First, a manufacturing method including a step of modifying a protective film formed by CVD will be described. (Example 1 of Manufacturing Method) A non-magnetic underlayer 1 and a magnetic layer 2 are sequentially formed on both surfaces of a non-magnetic substrate S by using a method such as a sputtering method, a vacuum deposition, or an ion plating, and a disk D is obtained.

An example of a method for obtaining the disk D will be specifically described. As the non-magnetic substrate S, an aluminum alloy substrate (hereinafter, referred to as “NiP-plated Al substrate”) on which a NiP plating film generally used as a substrate for a magnetic recording medium is formed, a glass substrate, a ceramic substrate, a flexible resin substrate Alternatively, a substrate in which NiP or another alloy is deposited on these substrates by plating or sputtering may be used. The average roughness Ra of the surface of the non-magnetic substrate S is 1
It is preferable to use those having an angle of up to 20 °. A predetermined surface average roughness Ra can be obtained by texture processing or the like.

The sputtering conditions for forming each of the above films are, for example, as follows. The inside of the chamber used for the formation is evacuated until the degree of vacuum becomes 10 ^-4 to 10 ^-7 [Pa]. The substrate is accommodated in the chamber, and the substrate is heated to obtain a desired coercive force, for example, 200 to 250 ° C.
Then, Ar gas is introduced and discharged to form a sputter film. At this time, the power to be supplied is 0.2 to
A desired film thickness can be obtained by adjusting the discharge time and the supplied power to 2.0 [kW].

As the non-magnetic underlayer 1, a conventionally known non-magnetic underlayer such as Cr, Ti, Ni, Si, Ta,
A single-composition film made of any one selected from W, or a film made of an alloy containing any of these as a main component and containing other elements within a range that does not impair its crystallinity is formed.
The function of the nonmagnetic underlayer 1 is to control the crystal orientation of the magnetic layer 2 made of a Co alloy. In forming the film, a single composition of Cr or Mo, W, V, T
It is preferable to use a sputtering target made of a material containing at least one selected from i, Nb, and Si. When the above material is used, the orientation of the magnetic layer 2 made of a Co alloy formed on the nonmagnetic underlayer 1 is improved, and the magnetic recording medium is improved in coercive force and noise characteristics, and is more suitable for high recording density. Become something.

The crystal grain size of the nonmagnetic underlayer 1 may affect the crystal grain size of the magnetic layer 2 made of a Co alloy. When the crystal grain size of the nonmagnetic underlayer 1 is reduced, B or Z
This can be achieved by using a sputtering target made of a material in which r, Ta, or the like is added to Cr or the Cr alloy of the nonmagnetic underlayer 1.

The thickness of the nonmagnetic underlayer 1 is not limited as long as a predetermined coercive force can be obtained. This thickness is preferably in the range of 100 to 1000 °, and 15
More preferably, it is 0-700 °. Non-magnetic underlayer 1
In the case where the film thickness is within the above range, the effect of improving the coercive force and S
This is preferable because the effect of improving NR is confirmed, and a magnetic recording medium suitable for high recording density can be obtained.

Further, the nonmagnetic underlayer 1 may have a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, the material may be a laminate of the same or different compositions among those described above. For example, a CrMo alloy layer (Mo content of 10 at% or less) or the like can be used on the Cr layer.

The magnetic layer 2 made of a Co alloy has a composition of Co / Cr, Co / Cr / Ta, or Co / Cr.
/ Cr / Pt-based, Co / Cr / Pt / Ta-based alloys, etc., may be used.

The thickness of the magnetic layer 2 made of a Co alloy is Brd (product of residual magnetization and film thickness [G
[μm]) in the range of 30 to 100 [Gμm] so that a predetermined recording / reproducing signal output can be obtained.

In order to perform the film formation efficiently and stably, the non-magnetic substrate S
It is preferable to apply a bias of -200 to -400 [V].

From the viewpoint of improving the orientation of the Co alloy and obtaining a high coercive force, a non-magnetic intermediate layer can be formed between the non-magnetic underlayer 1 and the magnetic layer 2. For example, a CoCr alloy (Cr content 50 at% or less) layer having a thickness of 25 ° or less can be formed.

Next, a method for forming a protective film will be described. The disk D formed up to the magnetic layer 2 is transported by a transfer device (not shown).
Is carried into a predetermined position in the CVD apparatus chamber 10 and the reaction gas supplied from the supply source is introduced into the introduction pipe 1.
The gas in the CVD apparatus chamber 10 is exhausted through the exhaust pipe 16 while being introduced into the CVD apparatus chamber 10 through 5 and 15, the gas is circulated in the CVD apparatus chamber 10, and the surface of the disk D is exposed to the reaction gas.

As the reaction gas, a gas containing a hydrocarbon, for example, a gas mainly containing a mixed gas of a hydrocarbon and hydrogen can be used. The mixing ratio of hydrocarbon and hydrogen in this mixed gas is such that hydrocarbon: hydrogen is 2: 1 to 1:
It is preferable to set it to 100 (volume ratio) in order to obtain a harder and more durable protective film mainly composed of carbon. In the present specification, “having a mixed gas as a main component” means that the gas component is contained at a rate of 90 vol% or more.

As the hydrocarbon, it is preferable to use one or more selected from 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.

It is preferred that lower hydrocarbons be used as the hydrocarbons. If the number of carbon atoms of the hydrocarbons exceeds the upper limit of the above range, it becomes difficult to supply them as a gas. This is because the decomposition of hydrogen becomes difficult to progress, and the protective film containing carbon as a main component contains a large amount of a polymer component having low strength.

At this time, the internal pressure in the CVD apparatus chamber 10 is reduced to 0.1 by appropriately adjusting the exhaust amount of the gas in the CVD apparatus chamber 10 using the exhaust amount adjusting valve 17.
The pressure is preferably 1 to 10 Pa. The flow rate of the reaction gas is preferably set to 50 to 500 sccm.

At the same time, high-frequency power of preferably 50 to 2000 W is applied using the high-frequency power supplies 12 and 12 to the electrodes 11 and 1.
1 to generate plasma, and a protective film containing carbon as a main component is formed on both surfaces of the disk D by plasma chemical vapor deposition using the above reaction gas as a raw material. The thickness of the protective film containing carbon as a main component can be 30 to 100 °, preferably 30 to 75 °. When power is supplied to the electrodes 11, 11, it is preferable that the phases of the power supplied to the electrodes 11, 11 be shifted from each other. This is because, by shifting the phases of the powers supplied to the electrodes 11, 11, the film formation rate can be improved, and the durability of the protective film containing carbon as a main component can be improved. The phase difference between the power supplied to both electrodes 11, 11 is 90
It is preferable that the angle is in the range of ゜ to 270 °, especially in the reverse phase (180 °)
It is preferred that

In addition, a commonly used method of forming a protective film containing carbon as a main component by CVD can also be used.

By forming a film using a plasma CVD apparatus, the carbon protective film contains a large amount of diamond-like carbon (hereinafter, referred to as “DLC”) component and has excellent strength. On the other hand, in the formed carbon protective film, the active portion on the film surface is hydrogenated, and there are many C—H bonds that are hardly polarized bonds, so that the chemical activity on the film surface is low. be able to.

Therefore, 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 protective film reforming apparatus shown in FIG. 5, and the carbon protective film is inspected after being left in an inspection gas atmosphere. Etching treatment using a gas for modifying a protective film under such a condition that the amount of extraction of the test gas component and / or the compound component formed containing the test gas component extracted with the solvent for use is not less than a reference value. By doing so, a magnetic recording medium on which the protective film has been modified is manufactured. Preferably, when melamine is used as the extraction component, the reference value is 0.06 [μg / 100 cm ² ] (more preferably 0.12 [μg / 100 cm ² ], and still more preferably 0.24 [μg / 100 cm ² ]). The condition is such that

That is, the protective film reforming treatment is a process in which the carbon protective film is left in a gas atmosphere for inspection and is extracted with a solvent for inspection, and the compound formed containing the gas component for inspection and / or the gas component for inspection. That is, the etching process is performed under such a condition that the amount of component extraction is equal to or more than the reference value.

The protective film modifying gas may contain one or more selected from the group consisting of Ar gas, oxygen gas and nitrogen gas.

The magnetic recording medium having the carbon protective film modified by the protective film modification treatment has a large amount of adsorption to the inside of the protective film since the extraction amount is equal to or more than the reference value. This is presumed to be due to the following reasons.

By exposing the protective film reforming gas to plasma during the modification of the protective film, the C—H bonds that are often present in the carbon protective film are broken by the plasma, and the broken C is newly replaced with nitrogen. And a bond such as a C—O bond, a C 結合 O bond, a C ＝ C bond, a C≡C bond, a C ＝ N bond, or a C≡N bond is formed depending on the type of the reforming gas used. These bonds are considered to be in a chemically active state. It is considered that the test gas is adsorbed on the site having a high activity. On the other hand, it is presumed that fine holes are formed by the gas from the surface of the protective film exposed to the protective film modifying gas toward the inside. These fine holes have a characteristic of increasing the amount of adsorption because the effective surface area involved in the adsorption is increased.

For these reasons, the carbon protective film subjected to the protective film reforming treatment has a large amount of adsorption to the inside of the protective film. It is believed to be

A protective film reforming gas supplied from a supply source (not shown) is introduced into the chamber through an introduction pipe, and the gas in the chamber is exhausted through an exhaust pipe, and the gas is circulated in the chamber so that the carbon protective film on both surfaces of the disk is formed. The surface is exposed to this protective film modification processing gas.

At this time, the amount of gas exhausted from the chamber is appropriately adjusted by using the exhaust gas amount adjusting valve, whereby
The internal pressure of the chamber is 2.4 to 8 Pa (preferably 2.4
To 6 Pa). If the chamber internal pressure is less than the above range, the modification of the surface of the protective film is insufficient, the amount of adsorption to the inside does not increase, and deposits easily adhere to the surface. On the other hand, if the internal pressure exceeds the above range, the surface of the protective film becomes chemically unstable, and the durability may be reduced.

When modifying the protective film, it is preferable to use a high-frequency power supply for 30 to 500 W (more preferably 30 to 300 W).
W, more preferably 30 to 200 W) is supplied to the electrode to generate plasma, and the plasma is generated from the above-mentioned nitrogen gas as a raw material, and the surface of the carbon protective film of the disk is reformed by the plasma.

If the electric power applied to the disk is less than the above range, the surface of the protective film is not sufficiently modified, the amount of adsorption to the inside does not increase, and the adhered substance easily adheres to the surface.
If the power exceeds the above range, the surface of the protective film becomes chemically unstable, and the durability may be reduced.

The protective film modification time is preferably 2 to 6 seconds (preferably 3 to 5 seconds). If the protective film modification treatment time is less than the above range, the modification of the surface of the protective film is insufficient, the amount of adsorption to the inside does not increase, and deposits easily adhere to the surface. If the treatment time exceeds the above range, the surface of the protective film becomes chemically unstable, and the durability may be reduced.

Further, in the infrared absorption curve of the surface of the protective film containing carbon as a main component, the peak intensity of carbon-hydrogen bond is 0.055 or less (more preferably 0.05 or less).
More preferably 0.04 or less. It is preferable to perform the reforming under the following conditions. When a lubricant is applied to the protective film containing carbon as a main component in such a state, the bonding between the protective film containing carbon as the main component and the lubricant can be increased, and the adhesion of the lubricant to the head can be reduced. Because you can do it.

When the reforming treatment is carried out, the surface of the protective film is adjusted to have a water contact angle of 80 ° or less (more preferably 75 ° C. or less) by adjusting conditions such as power applied to the disc, treatment time, and chamber pressure. Degree or less.) Is preferable. This is because the protective film having a water contact angle of 80 degrees or less has a sufficient bonding force with the lubricant, so that the lubricant does not easily adhere to the magnetic head.

If an impurity which induces the adhesion of a deposit on the surface of the protective film after passing through the plasma CVD apparatus is attached, the impurity is applied to the protective film during the modification of the protective film. It is removed from the protective film surface by the plasma derived from the reforming processing gas. Therefore, it is difficult for the deposit to adhere.

Further, in the case of using nitrogen gas as the protective film reforming gas, the nitrogen gas becomes plasma by the power supplied from the electrode, and the plasma breaks the bond of the carbon protective film, thereby forming a carbon nitride compound. Is preferred. Nitrogen gas is used because the carbon protective film can be easily adjusted to the design value. this is,
This is because, when nitrogen gas is combined with a component of the carbon protective film, it is difficult to generate a compound that easily gasifies, so that a change in the thickness of the protective film can be suppressed. In the modification of the protective film, the nitrogen content in the protective film measured by using the above ESCA is 5 to 40% (more preferably 5 to 25%) in terms of the nitrogen-carbon ratio.
%, More preferably 13 to 25%). If the amount of nitrogen is less than the above range, the modification of the surface of the protective film is insufficient, the amount of adsorption to the inside does not increase, and deposits easily adhere to the surface. Further, the activity of the surface of the protective film is reduced, the bonding force between the protective film and the lubricant is reduced, and the lubricant easily adheres to the head.

In this case, it is preferable that the protective film is modified under the condition that the carbon concentration of the carbon protective film in the vicinity of the surface in contact with the magnetic layer has a nitrogen concentration of 2 at% or less. If the ratio is out of this range, the magnetostatic properties of the magnetic layer deteriorate and the coercive force decreases, so that the magnetic recording medium is not suitable for a low flying height.

Since the protective film mainly composed of carbon formed by the CVD apparatus has an Id / Ig value of 3.5 or less by Raman spectroscopy, the condition for modifying the protective film is 3.5 or less. (More preferably 3.0 or less, further preferably 2.5 or less).

Next, a lubricant such as perfluoropolyether is applied on the protective film by dipping or the like to form a lubricating 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. A lubricating film is formed on a protective film containing carbon as a main component.
The lubricating film is formed by applying a lubricant on the above-mentioned protective film containing carbon as a main component using a conventionally known method, for example, a dipping method or a spin coating method. As the lubricant, a material containing any one selected from a Fomblin-based lubricant, a Gaudi-based lubricant, a Demnum-based lubricant, and a Krytox-based lubricant can be used.

(Example 2 of manufacturing method) Next, as another example,
An example of manufacturing without using a protective film modification process will be described. The disk D on which the magnetic layer 2 has been formed is carried into a predetermined position in the CVD device chamber 10 by a transfer device (not shown), and the reaction gas supplied from the supply source is introduced through the introduction pipes 15, 15. The gas in the CVD apparatus chamber 10 is exhausted through the exhaust pipe 16 while being introduced into the apparatus chamber 10, the gas is circulated in the CVD apparatus chamber 10, and the surface of the disk D is exposed to the reaction gas.

A protective film containing carbon as a main component is formed in the same manner as described above. At this time, a pulse DC bias is applied to the disk D so that internal adsorption is large, that is, the amount of extraction is equal to or more than a reference value. Film formation can be performed. By forming a film while applying a pulse DC bias to the disk D, the carbon protective film is formed to include the test gas component and / or the test gas component extracted with the test solvent after being left in the test gas atmosphere. The extracted amount of the compound component becomes equal to or more than the reference value. Preferably, when melamine is used as the extraction component, the reference value is 0.06 [μg / 100 c
m ² ] (more preferably 0.12 [μg / 100c
m ² ]. More preferably, 0.24 [μg / 100c
m ² ]).

By applying a bias to the disk, the plasma impact on the disk surface by the plasma becomes sufficient, and in addition to the effect of raising the disk temperature to dissociate the carbon-hydrogen bond, the surface is directly hit by the plasma. This is because the effect of dissociating the carbon-hydrogen bond can be easily obtained, and the carbon-hydrogen bond can be dissociated more efficiently, so that the amount of adsorption can be increased. In the acceleration method in which a grid voltage is applied in the conventional thermionic emission type plasma forming method, the effect of dissociating carbon-hydrogen bonds caused by directly striking the surface by plasma cannot be obtained, and the amount of adsorption cannot be increased. When the bias is applied to the disk D, the bias may be applied directly to the disk D or may be applied via a disk carrier (device for holding and transporting the disk D) (not shown).

The pulse DC bias applied to the disk D has an average voltage of -450 to -60 V, preferably -400.
The voltage is preferably from -150 V, more preferably from -350 to -200 V.

If the average voltage is less than the lower limit of the above range, the plasma impact on the surface of the disk D becomes too large, so that the excited active species in which the reaction gas is activated by plasma becomes difficult to fix on the disk D. For this reason, the densification of the protective film containing carbon as a main component becomes insufficient, and the sliding durability of the protective film tends to decrease.

If the average voltage exceeds the upper limit of the above range, the plasma impact on the surface of the disk D becomes too small, so that the modification of the protective film is insufficient and the amount of adsorption to the inside does not increase. In addition, it becomes easier for deposits to adhere to the surface.

Further, it is preferable that the temperature of the substrate is 130 ° C. or higher (preferably 150 ° C. or higher, more preferably 170 ° C. or higher) to form a protective film containing carbon as a main component. If the substrate temperature is lower than the lower limit of the above range, the amount of heat held by the substrate is small, so that the dissociation of carbon-hydrogen bonds (that is, thermal desorption of hydrogen) due to the amount of heat is difficult to occur. Insufficient quality, the amount of adsorption to the inside does not increase, and deposits tend to adhere to the surface.

As described above, by setting the average voltage of the pulse DC bias within the above range, the plasma impact property is made appropriate, and by setting the substrate temperature within the above range, dissociation of carbon-hydrogen bonds (that is, thermal desorption of hydrogen) is achieved. Separation) easily occurs. As a result, the surface of the protective film is sufficiently modified, the amount of adsorption to the inside is increased, and it is difficult for adhered substances to adhere to the surface.

Further, in the infrared absorption curve of the surface of the protective film containing carbon as a main component, the peak intensity of carbon-hydrogen bond is 0.055 or less (more preferably 0.05 or less).
More preferably 0.04 or less. It is preferable to apply a bias under the conditions described in (1). When a lubricant is applied to the protective film mainly composed of carbon in such a state, the bond between the protective film mainly composed of carbon and the lubricant can be increased, and the adhesion of the lubricant to the head can be reduced. Because you can do it.

At the time of forming a protective film containing carbon as a main component, a high-frequency power source can be used as the bias power source 13 and a high-frequency bias can be applied to the disk instead of the pulse DC bias. In this case, it is preferable to apply a high frequency power of 10 to 300 W (preferably 10 to 150 W) to the disk. The frequency can be the Rf frequency,
For example, one having a frequency of 13.56 MHz can be used.

More preferably, the aforementioned pulse DC bias has a positive voltage peak value, that is, a peak value in the positive region of the pulse portion of 10 to 100 V, preferably 20 to 7 V.
Preferably, it is 5V. If the peak value of the positive voltage is less than the lower limit of the above range, the negative charge accumulation on the disk surface cannot be sufficiently canceled at the time when the bias voltage reaches the positive region, and the excited active species becomes difficult to fix on the disk. Therefore, the densification of the protective film containing carbon as a main component tends to be insufficient, and the sliding durability of the protective film containing carbon as a main component tends to decrease.

Regarding the positive voltage peak value, pulse width, and frequency of the pulse DC bias, Id / Ig of the protective film containing carbon as a main component determined by Raman spectroscopy is 3.5 or less (more preferably 3.0 or less, more preferably 3.0 or less). Is preferably 2.5 or less.).

If the peak value of the positive voltage exceeds the upper limit of the above range, the reverse sputtering phenomenon easily occurs on the surface of the disk D, and the densification of the protective film containing carbon as a main component tends to be insufficient. The sliding durability of the film tends to decrease.

By setting the positive voltage peak value of the pulse DC bias within the above range, the negative charge accumulation on the disk surface is canceled when the bias voltage reaches the positive region, and the excitation active species is fixed on the disk. Can be promoted. As a result, the protective film containing carbon as a main component can be densified, and its sliding durability can be improved.

The frequency of the pulse DC bias is 1
kHz to 100 GHz (preferably 10 kHz to 1 GHz
z) is preferable. If the frequency is less than the lower limit of the above range, the accumulation of negative charges on the surface of the disk D cannot be sufficiently canceled at the time when the bias voltage reaches the positive region, and it becomes difficult for the excited active species to be fixed on the disk D. Densification of the protective film containing carbon as the main component tends to be insufficient, and the sliding durability of the protective film containing carbon as the main component tends to decrease. If the upper limit of the above range is exceeded, the reverse sputtering phenomenon is likely to occur on the surface of the disk D, and the densification of the protective film mainly composed of carbon tends to be insufficient, so that the sliding durability of the protective film mainly composed of carbon decreases. It's easy to do.

The pulse width of the pulse DC bias is 1 ns to 500 μs (preferably 10 ns to 50 μs).
It is preferred that If the frequency is less than the lower limit of the above range, the accumulation of negative charges on the surface of the disk D cannot be sufficiently canceled at the time when the bias voltage reaches the positive region, so that it becomes difficult for the excited active species to be fixed on the disk D. Densification of the protective film containing carbon as the main component tends to be insufficient, and the sliding durability of the protective film containing carbon as the main component tends to decrease. If the upper limit of the above range is exceeded, the reverse sputtering phenomenon is likely to occur on the surface of the disk D, and the densification of the protective film mainly composed of carbon tends to be insufficient, so that the sliding durability of the protective film mainly composed of carbon decreases. It's easy to do.

In this specification, the positive voltage peak value of the pulse DC bias refers to, for example, the peak value X of the positive region of the pulse portion in the pulse DC bias voltage waveform shown in FIG. In this example, the pulse width is the width Y of the pulse portion.

When forming a protective film by applying a bias, the surface of the protective film has a water contact angle of 80 degrees by adjusting the conditions of the applied bias, the processing time, and the pressure in the chamber. The following (more preferably 75 degrees or less) is preferable. This is because the protective film having a water contact angle of 80 degrees or less has a sufficient bonding force with the lubricant, so that the lubricant does not easily adhere to the magnetic head.

After forming a protective film containing carbon as a main component, a lubricating film is formed in the same manner as described above.

(Example 3 of Manufacturing Method) An embodiment of another manufacturing method combined with the sputtering method will be described. After obtaining the disk D in the same manner as described above, a protective film is formed as follows.
In the manufacturing method of the present embodiment, a disk D2 having a carbon protective film formed on the surface of the disk D by a CVD method in the same manner as any one of the above-described methods has a sputter target made of a material containing carbon therein, and an Ar gas. Or Ar
A mixed gas containing a gas and a nitrogen gas is carried into a sputtering chamber having means for introducing the mixed gas into the inside as a sputtering gas, and a plasma is generated by discharging the gas, so that carbon is further contained on the surface of the disk D2. Is formed by a sputtering method. At the time of sputtering, a condition is such that the amount of the test gas component extracted from the test solvent after being left in the test gas atmosphere and / or the compound component formed including the test gas component is equal to or more than a reference value. A protective film is formed while applying a bias to the disk. Preferably, when melamine is used as the extraction component, the reference value is 0.06 [μg / 100 cm ² ] (more preferably 0.12 [μg / 100 cm ² ], and still more preferably 0.24 [μg / 100 cm ² ]). The condition is such that The apparatus shown in FIG. 6 can be used. Here, reference numerals 41 and 42 denote sputter targets, and reference numeral 21 denotes a bias power supply capable of applying a bias to the disk D2.

When a protective film containing carbon as a main component is formed by a sputtering method by applying a bias to the disk, the protective film is formed in a state where the surface of the formed protective film is struck by plasma. Further, the protective film formed on the disk surface by the CVD method is modified. As a result, the formed film can have a large number of fine pores, so that the effective area for adsorption can be increased, and as a result, a sufficient internal adsorption amount can be obtained.

The magnetic recording medium thus manufactured is subjected to extraction of the test gas component and / or the compound component containing the test gas component, which is extracted with the test solvent after being left in the test gas atmosphere. A magnetic recording medium whose amount is equal to or more than the reference value is obtained.

The applied bias is 100 to 400 W
It is preferable to apply a high frequency power (preferably 100 to 200 W) to the disk. The frequency can be the Rf frequency, and for example, a frequency of 13.56 MHz can be used. This is because those in this range can have sufficiently fine pores and can have a sufficient amount of internal adsorption.

The bias to be applied can be a pulse DC bias similar to that shown in FIG. Preferably, the pulse DC bias applied to the disk D has an average voltage of -450 to -60 V, more preferably -400 to-
150V, more preferably -350 to -200V. By setting the average voltage of the pulse DC bias within the above range, the plasma impact property is made appropriate, and the effective surface area of the formed film for adsorption is increased. as a result,
The amount of adsorption to the inside is increased, and it is difficult for deposits to adhere to the surface.

The substrate temperature is preferably set to 130 ° C. or higher (more preferably, 150 ° C. or higher). By setting the substrate temperature within this range, the effective surface area for adsorption of the formed film is increased. As a result, the amount of adsorption to the inside increases, and it becomes difficult for deposits to adhere to the surface.

More preferably, the aforementioned pulse DC bias has a positive voltage peak value, that is, a peak value in the positive region of the pulse portion of 10 to 100 V, preferably 20 to 7 V.
5V. The frequency of the pulse DC bias is 1
kHz to 100 GHz (preferably 10 kHz to 1 GHz
z) is preferable. The pulse width of the pulse DC bias is 1 ns to 500 μs (preferably 10 ns).
５０50 μs). By setting the content within the above range, the plasma impact resistance can be made more appropriate, and the effective surface area for adsorption of the formed film becomes larger. As a result, the amount of adsorption to the inside increases, and it becomes more difficult for deposits to adhere to the surface.

Further, when a mixed gas containing an Ar gas and a nitrogen gas is used as a sputtering gas, the ESCA
The amount of nitrogen in the protective film measured using
It is preferable to set the sputtering conditions so as to be 40% (more preferably 5% to 25%, further preferably 13% to 25%). If the amount of nitrogen is less than the above range, the modification of the surface of the protective film is insufficient, the amount of adsorption to the inside does not increase, and deposits easily adhere to the surface. Further, the activity of the surface of the protective film is reduced, the bonding force between the protective film and the lubricant is reduced, and the lubricant easily adheres to the head.

Further, when a mixed gas containing Ar gas and nitrogen gas is used as a sputtering gas, the protective film containing carbon as a main component has a carbon nitride compound on the surface opposite to the magnetic layer, 2 at% at a position near the surface where the protective film mainly containing carbon is in contact with the magnetic layer.
It preferably has the following nitrogen concentration. If it is out of this range, the coercive force of the magnetostatic property is reduced, and the magnetic recording medium is not suitable for a low flying height.

Other conditions for sputtering when forming by sputtering are as follows, for example. The inside of the chamber used for the formation is evacuated until the degree of vacuum becomes 10 ^-4 to 10 ^-7 [Pa]. The substrate kept heated in the previous process is housed in the chamber, and Ar gas and nitrogen gas are supplied to the chamber at 0.5 to
Discharge is performed in a state where the pressure is introduced until the pressure reaches 1.0 [Pa] to generate plasma, and a sputtering film is formed using a target made of a material containing carbon as a raw material. At this time, the supplied power is 0.2 to 2.0 [kW],
By adjusting the discharge time and the power to be supplied, a desired film thickness can be obtained. It is preferable that the power supplied during the formation by the sputtering method be 0.2 to 2.0 [kW] (preferably 0.7 to 1.8 [kW]). 0.
If it is less than 2 [kW], a sufficient film thickness cannot be obtained. 2.
If it exceeds 0 [kW], the denseness of the protective film formed by the sputtering method may be reduced. Also, 2.0 [k
W], the carbon nitride compound formed by the sputtering method diffuses into the carbon layer in the direction of the magnetic layer, and the nitrogen concentration at a position near the surface where the protective film containing carbon as a main component is in contact with the magnetic layer is reduced. This is because there is a risk of exceeding 2 at%.

The thickness of the carbon film of the disk D2 formed by the CVD method is preferably set to 10 to 60 °. If it is less than 10 °, not only sufficient strength cannot be obtained, but also a carbon nitride compound formed by a sputtering method diffuses into the carbon film in the direction of the magnetic layer, and a protective film containing carbon as a main component is formed on the magnetic layer. This is because the nitrogen concentration at a position near the contact surface may exceed 2 at%.

Further, in the infrared absorption curve of the surface of the protective film containing carbon as a main component, the peak intensity of carbon-hydrogen bond is 0.055 or less (more preferably 0.05 or less).
More preferably 0.04 or less. It is preferable to perform sputtering under the conditions described in (1). When a lubricant is applied to the protective film containing carbon as a main component in such a state, the bonding between the protective film containing carbon as the main component and the lubricant can be increased, and the adhesion of the lubricant to the head can be reduced. Because you can do it.

When a protective film is formed by a sputtering method by applying a bias, the surface of the protective film can be formed by adjusting the conditions of the applied bias, the sputtering conditions, the processing time, and the chamber internal pressure. Those having a water contact angle of 80 degrees or less (more preferably 75 degrees or less) are preferable. This is because the protective film having a water contact angle of 80 degrees or less has a sufficient bonding force with the lubricant, so that the lubricant does not easily adhere to the magnetic head.

After forming a protective film mainly containing carbon, a lubricating film is formed in the same manner as described above.

(Other Examples of Manufacturing Method) In Example 3 of the manufacturing method described above, the step of forming the protective film by the CVD method can be replaced with the step of forming the protective film by the conventional sputtering method. Since a film similar to that of Example 3 of the manufacturing method can be formed on the surface side of the protective film, the above-described effects can be obtained.

In Example 3 of the above-described manufacturing method, the CV
The protective film can be formed by the sputtering method while applying the above-described bias without including the step of forming the protective film by the D method. Since a film similar to that of Example 3 of the manufacturing method can be formed on the surface side of the protective film, the above-described effects can be obtained. Further, when a mixed gas containing Ar gas and nitrogen gas is used as a sputtering gas, the protective film containing carbon as a main component has a carbon nitride compound on the surface on the side opposite to the magnetic layer, and contains carbon. It is preferable that the protective film as the main component has a nitrogen concentration of 2 at% or less at a position near the surface in contact with the magnetic layer. If it is out of this range, the coercive force of the magnetostatic property is reduced, and the magnetic recording medium is not suitable for a low flying height. For this purpose, for example, it can be manufactured by first forming a film under a condition containing no nitrogen gas and then forming the film with a gas containing nitrogen.

The magnetic recording medium manufactured by the manufacturing method of the embodiment described above is formed by including the test gas component and / or the test gas component extracted with the test solvent after being left in the test gas atmosphere. Since the extracted amount of the compound component is equal to or more than the reference value, the protective film mainly composed of carbon on the surface of the magnetic recording medium is hardly adhered to the adhered substance. When melamine is used as the extraction component, the reference value is preferably 0.06 [μg / 100 cm ² ].
Therefore, no matter adheres to the head even when the flying height of the head is reduced, so that a magnetic recording medium in which the fly stiction characteristics do not deteriorate even when the flying height of the head is reduced. Further, since the carbon protective film preferably has a peak intensity value derived from carbon-hydrogen bond by the FTIR method of 0.055 or less, the surface of the protective film can be stably covered with the lubricant to suppress the adhesion of deposits. . Preferably, the carbon protective film 3 is a denser and harder film because it contains nitrogen having a nitrogen-carbon ratio of 5 to 40% as measured by the ESCA measurement method. The magnetic recording medium of the present invention is preferably made of carbon that is harder and thinner and has excellent sliding durability and lubricating properties, suppresses the generation of abrasion powder that induces adhesion of deposits, and suppresses the generation of Ni corrosion. The magnetic recording medium has a protective film as a main component.

As a result, a magnetic recording medium with reduced spacing loss can be manufactured, and a magnetic recording medium capable of coping with a higher recording density than a conventional magnetic recording medium can be manufactured. it can.

When the magnetic recording medium manufactured according to the present invention is used, the flying height of the head can be further reduced. Therefore, it is preferable to increase the coercive force Hc of the magnetic recording medium in accordance with the flying height. For example, it is more preferably 3000 Oe or more, preferably 3500 Oe or more to realize higher recording density. A desired coercive force can be obtained by adjusting the composition, thickness, film configuration, and film forming conditions of the underlayer and the magnetic film within the above-described ranges.

A magnetic recording medium manufactured so as to have an extraction amount equal to or greater than a reference value determined by performing a preliminary test, for example, an extraction amount measured with respect to a magnetic recording medium having attached matter in a fly stiction test, is not limited to an extraction amount. Since the amount of the magnetic recording medium is equal to or more than the reference value, it is possible to easily manufacture the magnetic recording medium to which the adhered substance is hardly attached. That is, if the determination method of the present invention is used, it is possible to determine the difficulty of adhering substances, and thus it can be used as an index for process control for manufacturing a magnetic recording medium to which no adhering substances adhere. By using this index, appropriate process control can be performed, so that a magnetic recording medium with no attached matter can be easily manufactured.

Further, by using the determination method of the present invention, it is possible to accelerately inspect the difficulty of deposits on the protective film in a short time. Therefore, it is checked whether the deposits occur after a long period of actual use. Feedback to the manufacturing process can be made in a short time without inspection. Therefore, a magnetic recording medium can be stably manufactured.

Since such a magnetic recording medium has good fly stiction characteristics, it is possible to easily manufacture a magnetic recording medium having a reduced flying height and suitable for high recording density.

[0145]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Example 1 (After forming the protective film by the CVD method, the protective film was modified with nitrogen gas.) NiP plated Al substrate (diameter: 95 mm, plate thickness: 0.8 m)
m) was subjected to texture processing with an average roughness of Ra6Å, and then set in a chamber of a film forming apparatus (“3010” manufactured by Anelva). 2.0 × 10 ultimate vacuum in the chamber
After evacuation to ^-6 Pa, Cr was formed as a nonmagnetic underlayer to a thickness of 350 ° by a sputtering method, and Co16Cr6Pt3Ta (Cr content: 1) was formed thereon as a magnetic film.
6 at%, Pt content 6 at%, Ta content 3 at%,
The rest is Co. ) The alloy was formed to a thickness of 250 °. When the temperature of the substrate at the time of forming the protective film mainly containing carbon is 150
The substrate was heated using a heater heating method before forming the non-magnetic underlayer so as to reach a temperature of ° C. The substrate temperature was checked using a radiation thermometer through the window of the chamber immediately before forming the protective film containing carbon as a main component.

The disc D obtained as described above is
Subsequently, the wafer was transported into a CVD apparatus, and a hydrogenated carbon film having a thickness of 50 ° was formed on the magnetic film as a protective film containing carbon as a main component. During the formation, high-frequency power (frequency 13.56 MHz) was applied to the electrodes to generate plasma. In addition, a pulse DC bias was applied during the formation of the protective film containing carbon as a main component. The respective conditions are shown in Table 1. Next, the disk D on which the carbon protective film was formed was carried into the chamber 20 of the protective film reforming apparatus, and nitrogen was supplied into the chamber 20 as a protective film reforming gas. At the same time, high frequency power (frequency 13.56 MHz)
Is applied to the disk D to generate plasma.
The carbon protective films on both sides were modified. Table 1 shows the conditions for the reforming treatment. Next, Fomblin lubricant Zd
ol2000 (manufactured by Ausimont Co.) was applied to a thickness of about 15 ° by a dipping method to form a lubricating layer on the protective film containing carbon as a main component.

Example 2 (Protective film was modified by oxygen gas after forming the protective film by the CVD method.) The magnetic recording medium was the same as in Example 1 except that the protective film modified gas and the conditions shown in Table 1 were changed. Was made.

Example 3 (A after forming protective film by CVD method)
The protective film was reformed by r gas. A magnetic recording medium was manufactured in the same manner as in Example 1 except that the protective film modified gas and conditions shown in Table 1 were changed.

Examples 4 to 7 (After forming a protective film by a CVD method, a protective film was formed by a sputtering method using nitrogen gas and Ar gas.) A disk D was manufactured in the same manner as in Example 1. Subsequently, the wafer is transported into a CVD apparatus, and a hydrogenated carbon film is deposited on the magnetic film as a protective film containing carbon as a main component.
Å was formed. During the formation, high-frequency power (frequency 13.56 MHz; power 750 W) was applied to the electrodes to generate plasma. Further, a pulse DC bias was applied during the formation of the protective film. Further, a protective film containing a carbon nitride compound was formed thereon by a sputtering method. In the fourth and fifth embodiments, high frequency bias (frequency 13.5
6 MHz. ) Was applied. In Examples 6 and 7, the disk was formed while applying a pulse DC bias to the disk. The thickness of the protective film formed by the sputtering method was 10 °. At this time, the thickness of the protective film formed by the CVD method was 40 °. Each condition is shown in Table 1.

Examples 8 to 13 (Protective film was formed by a CVD method applying a pulse DC bias.) A disk D was manufactured in the same manner as in Example 1. Subsequently, the film is transported into a CVD apparatus, and a hydrogenated carbon film is formed on the magnetic film as a protective film containing carbon as a main component.
Å was formed. During the formation, high-frequency power (frequency 13.56 MHz) was applied to the electrodes to generate plasma. In Examples 8 to 11, the disk was formed while applying a pulse DC bias to the disk. In Examples 12 and 13, the disk was formed while applying a high frequency bias (frequency of 13.56 MHz) to the disk. The respective conditions are shown in Table 2.
Next, a lubricating layer was formed in the same manner as in Example 1.

Examples 14 to 16 and Comparative Example 1 (Protective film was formed only by sputtering) A disk D was manufactured in the same manner as in Example 1. further,
A protective film containing carbon as a main component was formed thereon by sputtering under the conditions shown in Table 1. Example 14-
In No. 16, a high frequency bias (frequency 13.56
MHz. Power 200W. ) Was applied.
Comparative Example 1 was formed without applying a bias. The thickness of the protective film containing carbon as a main component was 50 °. next,
A lubricating layer was formed in the same manner as in Example 1.

Comparative Example 2 (Protective Film Formed by Conventional CVD Method) A magnetic recording medium was manufactured in the same manner as in Example 1 except that the protective film modification treatment was not performed.

On the other hand, in each embodiment, before applying the lubricant, the infrared absorption curves of the surface of the magnetic recording medium before and after the formation of the protective film containing carbon as the main component were measured, and carbon was used as the main component. The protective film infrared absorption curve was calculated. Thereafter, a peak intensity value derived from a carbon-hydrogen bond was determined. The measurement position was a radius of 20 mm of the disk. Table 1 shows the measurement results.

The fly stiction test was performed by the following method. First, a head (an MR head used in an actual magnetic recording / reproducing apparatus) is placed at a position having a radius of 19.5 mm, and the number of rotations is 7200 r in an environment of 40 ° C. and 80% humidity.
Rotate at pm. After that, the position of the head is
m while maintaining the rotational speed at 7200 rpm.
Leave for 8 hours. Next, the position of the head is again set to 19.5 mm.
And the rotation of the magnetic recording medium was stopped, and the magnetic recording medium was allowed to stand still for 6 hours in that state. Thereafter, one cycle (starting up to 7200 rpm in 5 seconds, 720
0 rpm is maintained for 1 second, the rotation is stopped for 5 seconds, and the system is allowed to stand for 1 second.
p) was performed. The state of adhesion of the lubricant to the head after the fly stiction test was completed was evaluated as follows. The surface of the head on the disk side where the test was completed was observed with an optical microscope (magnification: 240 times), and those with attached matter were counted as the occurrence of attached matter. The measured results are shown in Tables 1, 2 and 3.

The amount of melamine extracted was measured under the following conditions. A magnetic recording medium of each of Examples and Comparative Examples was mounted on a spindle in a commercially available magnetic recording / reproducing apparatus, and 1 g of melamine was added to 2 g of polyurethane paste as a source of impurity gas.
The kneaded material was applied on a 70 mm × 25 mm aluminum wheel piece and dried, then put together in a magnetic recording / reproducing apparatus, and the magnetic recording medium was rotated at 3000 rpm in an atmosphere of 80 ° C. and 20% RH for 30 hours. I left it. Thereafter, each magnetic recording medium was taken out and kept at 80 ° C. for 30 minutes.
It was immersed in 1 ml of ethanol for 1 hour. The extracted melamine was quantitatively measured using GC-MS (Automass, manufactured by JEOL Ltd.). The measured results are shown in Tables 1, 2 and 3.

ESCA equipment (Sages, Sage)
100), the nitrogen-carbon ratio was determined from the amount of nitrogen on the surface of the protective film based on the following equation. Tables 1 and 2 show the measured results.
And Table 3 together. Nitrogen carbon ratio (%) = (N1s peak area) / (C1s 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)

In addition, a Raman spectrometer (Jobin-
The carbon protective film was analyzed by Raman spectroscopy (light source: Ar laser, wavelength: 514.5 nm, output: 100 mW, exposure time: 10 seconds, method for obtaining area: Gaussian fitting) using Yvon Corporation. Table 1 shows the results.
The results are shown in Tables 2 and 3.

[0158]

[Table 1]

[0159]

[Table 2]

[0160]

[Table 3]

[0161]

According to the inspection method of the present invention, the test gas component and / or the test gas component extracted from the magnetic recording medium with the test solvent after leaving the magnetic recording medium in the test gas atmosphere are used. By comparing the extracted amount of the compound component contained and formed with a preset reference value, the occurrence of head deposits can be inspected without performing a long-term actual use test, so that the inspection can be easily performed. Further, the present inspection method can determine manufacturing conditions under which no deposits are generated on the head. In addition, the inspection result can be fed back to the manufacture of the magnetic recording medium.

The magnetic recording medium of the present invention is characterized in that the magnetic recording medium is left in a gas atmosphere for inspection and is extracted with a solvent for inspection, and the compound component containing the inspection gas component and / or the gas component containing the inspection gas component is formed. Since the magnetic recording medium has an extraction amount equal to or more than the reference value, the fly stiction characteristics are improved, so that the medium can be used with a low flying height and can be used at a high recording density.

Further, according to the manufacturing method of the present invention, since the above-described inspection method is used, the manufacture of the magnetic recording medium can be facilitated.

Further, according to the magnetic recording / reproducing apparatus of the present invention, since the above-mentioned magnetic recording medium is used, the fly stiction characteristic is improved, and the magnetic recording medium can be used with the distance between the magnetic head and the magnetic recording medium shortened. This is a device capable of density.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a magnetic recording medium of the present invention.

FIG. 2 is a diagram showing the amount of deposits on the surface of a magnetic recording medium when the total amount of flying gas is changed.

FIG. 3 is a schematic configuration diagram showing an example of a magnetic recording / reproducing apparatus using the magnetic recording medium shown in FIG.

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

FIG. 5 is a configuration diagram showing a protective film reforming apparatus used for carrying out an embodiment of the method of manufacturing a magnetic recording medium according to the present invention.

FIG. 6 is a configuration diagram showing a sputtering apparatus used for carrying out one embodiment of a method for manufacturing a magnetic recording medium of the present invention.

FIG. 7 is an explanatory diagram for explaining an average voltage value and a positive voltage peak value of a pulse DC bias.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nonmagnetic underlayer 2 Magnetic layer 3 Protective film 4 Lubricating layer 10 Chamber 11 Electrode 12 High frequency power supply 13 Bias power supply 14 Process gas supply source 15 Introducing pipe 16 Exhaust pipe 17 Displacement control valve 20 Chamber 21 High frequency power supply for bias 24 Matching device Reference Signs List 25 introduction pipe 26 exhaust pipe 27 displacement control valve 30 magnetic recording medium 31 medium drive unit 32 magnetic head 33 head drive unit 34 recording / reproducing signal processing system 41 sputter target 42 sputter target S non-magnetic substrate D disk

Claims (16)

[Claims] 1. A method of manufacturing a magnetic recording medium comprising a non-magnetic substrate and at least a non-magnetic underlayer and a magnetic layer on which a protective film containing carbon as a main component is formed. In the method for examining adhesion characteristics, the amount of the test gas component and / or the compound component formed including the test gas component extracted with the test solvent after leaving the magnetic recording medium in the test gas atmosphere is reduced. A method for inspecting a magnetic recording medium, wherein it is determined that the value is equal to or greater than a preset reference value. 2. A test gas component generated in a magnetic recording / reproducing apparatus having a magnetic recording medium and a magnetic head for recording / reproducing information on / from the magnetic recording medium. 2. The inspection method according to 1. 3. The gas component for inspection is one or more selected from siloxane gas, acrylic acid gas, vaporized melamine, vaporized lubricant, vaporized higher fatty acid, vaporized phthalate ester, and vaporized dioctyl phthalate. The inspection method according to claim 1 or 2, wherein the inspection method is a combination of two or more. 4. The inspection method according to claim 1, wherein the inspection gas component is a gas component generated from a member used inside the magnetic recording reproduction apparatus. 5. The test solvent is methanol, ethanol,
One or two selected from isopropyl alcohol and water
The inspection method according to any one of claims 1 to 4, wherein the inspection method is one or more combinations. 6. The inspection method according to claim 1, wherein a reference value when the extraction component is melamine is 0.06 [μg / 100 cm ² ]. 7. A magnetic recording medium in which at least a non-magnetic underlayer and a magnetic layer are formed on a non-magnetic substrate, and a protective film containing carbon as a main component is formed on the non-magnetic substrate. A magnetic recording medium in which the amount of the test gas component and / or the compound component formed containing the test gas component extracted with the test solvent after being left inside is equal to or greater than a reference value. 8. The magnetic recording medium according to claim 7, wherein the reference value when the extraction component is melamine is 0.06 [μg / 100 cm ² ]. 9. An infrared absorption curve of a surface of a protective film containing carbon as a main component has a peak intensity value derived from a carbon-hydrogen bond of 0.
The magnetic recording medium according to any one of claims 7 to 8, wherein the value is 055 or less. 10. The protective film containing carbon as a main component has a nitrogen-carbon ratio of 5 to 40 at%.
10. The magnetic recording medium according to any one of claims 9 to 9. 11. The magnetic recording medium according to claim 7, wherein the value of Id / Ig on the surface of the protective film containing carbon as a main component is 3.5 or less. 12. A method for manufacturing a magnetic recording medium comprising forming a protective film containing carbon as a main component on a disk having at least a nonmagnetic underlayer and a magnetic layer formed on a nonmagnetic substrate. The extraction amount of the test gas component and / or the compound component formed containing the test gas component extracted with the test solvent after being left in the test gas atmosphere is equal to or more than a reference value. Of manufacturing a magnetic recording medium. 13. The magnetic recording according to claim 12, wherein the method of forming the protective film containing carbon as a main component includes a sputtering method of forming the protective film while applying a bias to the disk. The method of manufacturing the medium. 14. A method of forming a protective film containing carbon as a main component is performed by a plasma CV using a reactive gas containing hydrocarbon as a raw material.
The method for manufacturing a magnetic recording medium according to claim 12, wherein method D is included. 15. A method of forming a protective film containing carbon as a main component, comprising the steps of forming a plasma CV using a reaction gas containing hydrocarbon as a raw material.
13. The method for manufacturing a magnetic recording medium according to claim 12, comprising a forming step by a D method and a forming step by a sputtering method of forming a protective film while applying a bias to the disk. 16. A magnetic recording medium comprising: a magnetic recording medium; and a magnetic head for recording and reproducing information on and from the magnetic recording medium, wherein the magnetic recording medium is the magnetic recording medium according to any one of claims 7 to 11. A magnetic recording / reproducing apparatus characterized by the above-mentioned.