JP2949875B2 - Manufacturing method of magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium used in a magnetic recording device such as a magnetic disk device. More specifically, the present invention relates to a non-magnetic support made of titanium and silicon on a non-magnetic support. The present invention relates to a method for manufacturing a magnetic recording medium in which a crystalline alloy layer, a magnetic layer, and a protective layer are formed in this order.

[0002]

2. Description of the Related Art In a magnetic recording medium, a magnetic layer is coated on a non-magnetic support having a flat surface such as a glass substrate, a protective layer such as a carbon film is further coated thereon, and an organic lubricating layer is further coated thereon. Coated ones are known. Then, in order to control the crystal grain size of the magnetic layer, a crystalline metal layer such as a chromium film is coated as a base layer of the magnetic layer,
Japanese Patent Laid-Open Publication No.
It is disclosed in Japanese Patent Publication No. 3-273208.

According to the present invention, in order to form a good magnetic film on an amorphous alloy layer of titanium and silicon, it is preferable to form the amorphous alloy layer of titanium and silicon by any method. Was obtained in the process of examining
There is provided a method of manufacturing a magnetic recording medium having good magnetic properties, especially high coercive magnetic force angle shape ratio having a base film of the amorphous alloy layer of the titanium and silicon.

[0004]

Means for Solving the Problems] The magnetic characteristics of the magnetic recording medium amorphous alloy layer and the magnetic layer of titanium and silicon and the protective layer are sequentially formed on a nonmagnetic support, especially coercive magnetic <br / > power angle shape ratio is dependent by the method of forming the titanium and amorphous alloy layer of silicon.

[0005] The present invention provides an amorphous alloy layer comprising at least titanium and silicon on a non-magnetic support,
A method of manufacturing a magnetic recording medium in which a magnetic layer and a protective layer are sequentially formed, wherein the amorphous alloy layer is formed by sequentially laminating a titanium film and a silicon film by a sputtering method in a reduced pressure inert gas. Thereafter, the stacked film is heated in a reduced pressure inert gas to thermally diffuse the silicon into the titanium to form the magnetic recording medium.

[0006] When coating the titanium film by the sputtering method, a metal titanium target is used, and a direct current or high frequency glow discharge in an inert gas is used. Further, when the silicon film is coated on the titanium film surface by the sputtering method, a silicon target is used and a direct current or high frequency glow discharge in an inert gas is used. The temperature of the substrate when coating the film can be from room temperature to 550 ° C. The temperature of thermal diffusion after coating these films is preferably 300 to 550 ° C. If the temperature is lower than 300 ° C., the rate of diffusion of titanium into silicon is extremely low. Thus, if the temperature is higher than 550 ° C., the alloy film becomes non-crystalline, which is not preferable.

It is preferable that the laminated body of the titanium film and the silicon film is heated in an inert gas atmosphere or a low pressure in a sputtering apparatus after coating the silicon film. By heating, titanium is thermally diffused into silicon, and the whole or a part of the laminate becomes an amorphous alloy layer composed of titanium and silicon. By selecting a heating temperature and a heating time, the entire stack of titanium and silicon may be made to be an amorphous alloy, and an amorphous alloy is formed only near the surface on the opposite side of the nonmagnetic support. May be.

The thickness of the amorphous alloy layer is preferably at least 2 nm. If the thickness is less than 2 nm, it will be difficult to coat as a continuous film. To make it a continuous film,
The thickness is preferably 3 nm or more, and more preferably 50 nm or less from the viewpoint of minimizing the decrease in productivity of the magnetic recording medium.

As a method for forming the magnetic layer and the protective layer, a known sputtering method can be used, and the amorphous alloy layer, the magnetic layer and the protective layer are successively formed on the amorphous alloy layer and the magnetic layer. It is preferable to form without exposure. As such an apparatus for continuously forming each of the layers, an in-line sputtering apparatus having a plurality of cathodes for coating the non-magnetic support while moving it against the target surface is preferably used. In this case, after the titanium film is coated and the silicon film is further coated, the laminate can be heated in an inert gas atmosphere in an in-line sputtering apparatus or in a high vacuum in which no gas is introduced. In order to immediately cover the magnetic layer immediately after forming the amorphous alloy layer composed of titanium and silicon, the temperature for performing the thermal diffusion is set at 4 ° C.
More preferably, the temperature is set to 00 to 550 ° C.

[0010] The method of the present invention can be applied not only to the production of a magnetic recording medium having an amorphous alloy layer provided directly on a non-magnetic support, but also to the magnetic recording medium prior to the formation of the amorphous alloy layer. A so-called gettering action for absorbing a gas released from a non-magnetic support prior to forming a magnetic recording medium or an amorphous alloy layer, which is provided with a concavo-convex structure for forming concavities and convexities on the surface of a protective layer of the medium. Can be used to manufacture a magnetic recording medium provided with a metal film having

The non-magnetic support used in the present invention includes a glass plate, an aluminum plate and a ceramic plate.

[0012]

The laminate in which the titanium film and the silicon film are sequentially formed is heated in an inert gas atmosphere,
Silicon is thermally diffused into titanium, and an amorphous alloy layer is formed at least in the vicinity of the interface of the laminate opposite to the nonmagnetic support. The amorphous alloy layer has a uniform crystal grain size of the magnetic layer coated on the amorphous alloy layer and affects the crystal orientation of the crystalline metal underlayer coated prior to the coating of the magnetic layer. To improve the magnetic properties of the magnetic layer.

[0013]

EXAMPLES The present invention will be described below with reference to examples. FIG.
1 is a schematic sectional view of an in-line type sputtering apparatus used for carrying out the present invention, wherein a vacuum chamber 1 includes a load chamber 2;
The chambers are composed of film forming chambers 3, 4, 5, 6 and an unloading chamber 7, and these chambers are connected by a gate valve 8 which can be opened and closed (a vacuum exhaust pump connected to each chamber is not shown). The non-magnetic support 21 is set on the conveyor 16 of the load chamber 2 and is coated with a predetermined layer when transported to the unload chamber 7. In each film forming chamber, a gas supply pipe 9 is provided so that gas can be introduced from an external gas cylinder 14 into the film forming chamber, and the gas flow control valve 10 controls the amount of gas introduced. In each chamber, a heater 15 for heating the nonmagnetic support, a cathode 11 supplied with power from an external DC power supply 13 are provided, and a target 12 of a layer to be coated is provided on the cathode surface. A gas was introduced into each of the film forming chambers, a voltage was applied to the target in a predetermined reduced-pressure atmosphere, and the target was sputtered by glow discharge to cover the surface of the nonmagnetic support.

FIG. 2 is a partial sectional view of an embodiment of a magnetic recording medium obtained by implementing the present invention. The magnetic recording medium 20 of the first embodiment shown in FIG.
1 is coated with a metal film 23 having a gettering action against a gas such as moisture or oxygen, and a concavo-convex formation 24 for forming concavities and convexities on the surface of the magnetic recording medium is formed on the metal film 23 in a discontinuous island-like structure. And an amorphous alloy layer 22 made of titanium and silicon is coated thereon,
A chromium underlayer 25 is coated thereon, a cobalt-nickel-chromium alloy magnetic layer 26 is coated thereon, a carbon protective layer 27 is coated thereon, and a perfluoroalkyl lubricating layer is further formed thereon. 28 are applied.

The magnetic recording medium 20 according to the second embodiment shown in FIG. 2B has an amorphous alloy layer 22 made of titanium and silicon, a chromium underlayer 25, and a cobalt-nickel layer on a nonmagnetic support 21. A magnetic layer 26 of chromium alloy and a carbon protective layer 27 are successively coated,
A lubricating layer 28 of perfluoroalkyl is applied thereon.

A magnetic recording medium 20 according to a third embodiment shown in FIG. 2C has an amorphous alloy layer 22 made of titanium and silicon,
A platinum alloy magnetic layer 26 and a carbon protective layer 27 are sequentially coated, and a perfluoroalkyl lubricating layer 28 is applied on the carbon protective layer 27.

Example 1 A glass plate having a soda lime composition which has been processed into a disk shape and chemically strengthened is thoroughly washed, set in a load chamber in an in-line sputtering apparatus, and continuously placed on the glass plate as follows. A laminated film including an amorphous alloy layer made of titanium and silicon, a magnetic layer, and a protective layer was covered. First, a glass plate was placed in a load chamber under a pressure of 0.00013 Pascals.
Heated to 00 ° C. Thereafter, a titanium target was sputtered in an argon atmosphere of 0.13 pascal, and a titanium gas gettering layer having a thickness of 30 nm was coated on a glass plate heated to 200 ° C. Next, while being heated to 200 ° C., a concavo-convex formed product of aluminum was formed. The conditions for forming the irregularities were as follows:
The sputtering was performed in an argon atmosphere of 3 Pascal, and the amount of aluminum to be sputtered was such that the glass plate was kept at room temperature and a smooth continuous film having a thickness of 10 to 20 nm was coated. Next, while moving over a titanium target in an argon atmosphere of 0.13 palcal,
A titanium film having a thickness of 0 nm was coated, and then a silicon film having a thickness of 10 nm was coated while moving over a silicon target. Thereafter, this glass plate was heated to 300 ° C. in the film forming chamber. Next, a chromium target was sputtered in an argon atmosphere of 0.13 pascal to cover a chromium underlayer film having a thickness of 150 nm. Next, a cobalt nickel chromium alloy target was sputtered in an argon atmosphere of 0.13 pascal to cover a magnetic film having a thickness of 60 nm.
Next, a carbon target was sputtered in an argon atmosphere of 0.13 pascal to cover a carbon protective layer having a thickness of 30 nm. Next, the glass plate was transferred to an unloading chamber, taken out of the sputtering apparatus, and a perfluoroalkyl-based lubricating oil was applied on the carbon protective layer to obtain a magnetic recording medium having a film configuration shown in FIG.

[0018] When the coercive force of the obtained magnetic recording medium was measured, about 1500 Oe, the coercive force squareness shape ratio S ^* 0.
91 was a good value. The glide characteristics were 2 micro inches or less, and the recording / reproducing characteristics were good. When the distance flying height between the head and the magnetic disk surface was measured as 3 micro inches, the S / N value was 30 dB and the D / D value was 30 dB.
50 (the frequency at which the output is １ ／ of the value at the low frequency) was 60 kFCI (the number of magnetization reversals per inch).

Example 2 A glass plate having a soda lime composition which had been processed into a disk shape and which had been chemically strengthened was thoroughly washed and set in a load chamber in an in-line sputtering apparatus. First, it was heated to 200 ° C. under a pressure of 0.00013 Pascal.

Next, while the glass plate is moved to the film forming chamber and moved, the laminated film of the titanium film and the silicon film is coated in an argon atmosphere of 0.13 pascal in the same manner as in the first embodiment. And an amorphous alloy layer composed of silicon. Next, a chromium target is sputtered in an argon atmosphere of
A chrome underlayer with a thickness of nm was coated. Next, a cobalt nickel chromium alloy target was sputtered in an argon atmosphere of 0.13 pascal to cover a magnetic layer of 60 nm.
Next, a carbon target was sputtered in an argon atmosphere of 0.13 pascal to cover a carbon protective layer having a thickness of 30 nm. Next, the glass plate was transferred to an unloading chamber, taken out of the sputtering apparatus, and a perfluoroalkyl-based lubricating oil was applied on the carbon protective layer to obtain a magnetic recording medium having a film configuration shown in FIG. 2B.

[0021] When the coercive force of the obtained magnetic recording medium was measured, about 1500 Oe, the coercive force squareness shape ratio S ^* 0.
93 was a good value. The glide characteristic was 2 micro inches or less, and the recording / reproducing characteristics were good. When the distance flying height between the head and the magnetic disk surface was measured as 3 micro inches, the S / N value was 32 dB and the D / D value was 32 dB.
50 (the frequency at which the output becomes 出力 of the value at the low frequency) was 65 kFCI (the number of magnetization reversals per inch).

Example 3 A glass plate having a soda lime composition which had been processed into a disk shape and which had been chemically strengthened was thoroughly washed and set in a load chamber in an in-line sputtering apparatus. First, it was heated to 200 ° C. under a pressure of 0.00013 Pascal. Next, the glass plate was transferred to a film forming chamber, and a 30-nm-thick amorphous layer made of titanium and silicon was formed in the same manner as in Example 1. Next, an alloy target composed of cobalt, nickel and platinum was sputtered in an argon atmosphere of 0.13 pascal,
A 0 nm thick alloy magnetic layer (15 at% platinum, 7 at% nickel, 78 at% cobalt) was coated. Next, a carbon target was sputtered in an argon atmosphere of 0.13 pascal to cover a carbon protective layer having a thickness of 30 nm. Next, the glass plate was transferred to an unloading chamber, taken out of the sputtering apparatus, and a perfluoroalkyl-based lubricating oil was applied on the carbon protective layer to obtain a magnetic recording medium having a film configuration shown in FIG.

[0023] When the coercive force of the obtained magnetic recording medium was measured, about 1500 Oe, the coercive force squareness shape ratio S ^* 0.
75 was a good value. The glide characteristics were 2 micro inches or less, and the recording / reproducing characteristics were good. When the distance flying height between the head and the magnetic disk surface was measured as 3 micro inches, the S / N value was 33 dB and the D / D
50 (the frequency at which the output becomes 出力 of the value at the low frequency) was 65 kFCI (the number of magnetization reversals per inch).

[0024]

According to the present invention, to produce an amorphous alloy layer consisting of the required titanium and silicon to obtain magnetic properties especially magnetic recording medium is large coercive magnetic <br/> force angle shape ratio Can be done. The magnetic recording medium obtained by the method of the present invention has a large coercive magnetic force angle shape ratio greater coercive force, large further recording playback of S / N.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a sputtering apparatus used to carry out the present invention.

FIG. 2 is a partial cross-sectional view of a magnetic recording medium obtained according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum tank 2 Load chamber 3, 4, 5, 6 Film formation chamber 7 Unload chamber 8 Gate valve 9 Gas supply pipe 10 Gas flow control valve 11 Cathode 12 Target 13 DC power supply 14 Gas cylinder 15 Heater 20 Magnetic recording medium 21 Non Magnetic support 22 Titanium-silicon amorphous alloy layer 23 Gas gettering layer 24 Concavo-convex formation 25 Underlayer 26 Magnetic layer 27 Protective layer 28 Lubricating layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 5/85 G11B 5/66

Claims (3)

(57) [Claims] 1. An amorphous alloy layer comprising at least titanium and silicon on a nonmagnetic support, a magnetic layer,
In the method of manufacturing a magnetic recording medium in which a protective layer and a protective layer are sequentially formed, the amorphous alloy layer is formed by sequentially laminating a titanium film and a silicon film by a sputtering method in a reduced pressure inert gas. A method for manufacturing a magnetic recording medium, comprising: heating a laminated film in an inert gas under reduced pressure to thermally diffuse the silicon into the titanium. Wherein said thermal diffusion method of manufacturing a magnetic recording medium according to claim 1 carried out at a temperature of 300 to 550 ° C.. The wherein forming the protective layer and the amorphous alloy layer and the magnetic layer sequentially claim 1, characterized in that it is done immediately after a sputtering method in an atmospheric gas under reduced pressure or
A method for manufacturing a magnetic recording medium according to claim 2 .