JPH04332915A - Fixed magnetic disk manufacturing method - Google Patents

Abstract

PURPOSE:To manufacture a three-layer film simply and continuously by using a CVD method using ozone or N2O and oxygen as a reaction gas in the manufacturing method of a fixed magnetic disk in which an oxide thin film by an NaCl- type crystal structure is formed on a disk substrate. CONSTITUTION:In this manufacturing method, a fixed magnetic disk having a structure where an oxide thin film 8 provided with a preferentially oriented NaCl-type crystal structure is formed on a disk substrate 7, an iron oxide magnetically soft thin film 9 by a spinel-type crystal structure is formed on it and, in addition, an iron oxide film 10 by a spinel-type crystal structure containing cobalt provided with a pillar-shaped structure is formed on it is manufactured by a manufacturing method which utilizes the activity of a plasma and a CVD reaction. Thereby, ozone or N2O used as a reaction gas and steam generate active radicals in the plasma. As a result, the fixed magnetic disk whose reliability such as durability, hardness or the like is excellent can be manufactured comparatively easily and at a low temperature.

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 fixed magnetic disk that is highly reliable and compatible with high-density magnetic recording.

0002

2. Description of the Related Art In the recent highly information-oriented society, the amount of information to be stored continues to increase year by year, and there is also an increasing demand for larger capacity and higher density storage devices.

Under these circumstances, recording media used in fixed magnetic disks used as computer peripherals are made by coating a conventional aluminum disk substrate with gamma iron oxide-based acicular magnetic powder. The coating type has changed to a Co-Ni/Cr alloy thin film type using plating or sputtering methods, and higher density has been achieved.

0004

[Problem to be solved by the invention] However, Co-Ni/
Since the Cr thin film is an alloy, there are problems with durability, etc., so the structure of the magnetic disk is (lubricating layer/protective layer/
It has a five-layer structure (Co--Ni magnetic layer/Cr layer/Ni--P plating layer/aluminum substrate), and has the drawback that the manufacturing process is complicated.

FIG. 6 shows a cross section of a thin film type fixed magnetic disk made of a Co--Ni/Cr alloy, which is a conventional fixed magnetic disk. In the figure, 1 is an aluminum substrate, 2 is a Ni-P plating layer, 3 is a Cr layer, and 4 is a Co-N
i is a magnetic layer, 5 is a protective layer, and 6 is a lubricating layer.

[0006] Furthermore, the fixed magnetic disk is made of Co-Ni.
Since the magnetic layer 4 is a longitudinal recording medium, if the recording wavelength is shortened to further increase the recording density, recording becomes difficult due to the influence of the demagnetizing field.

[0007] Therefore, as a magnetic recording medium that enables perpendicular recording, which is a recording method that improves the above-mentioned drawbacks, a C
Research on o-Cr thin film media has been actively conducted. However, as in the case of the Co-Ni/Cr alloy thin film type recording medium shown in Figure 6, since the Co-Cr medium is also an alloy, there is a reliability problem, so an amorphous layer is formed on the surface of the Co-Cr thin film. There is a problem in that a protective layer 5 of carbon film or Co oxide must be provided.

On the other hand, in a fixed magnetic disk drive, reducing the flying height of the magnetic head relative to the magnetic disk as much as possible reduces output loss (spacing loss) due to spacing between the magnetic head and the magnetic disk. In order to reduce the noise, it leads to an improvement in recording density.Recently, in order to enable high recording density, 0.
It is required to run with a flying height of about 0.05 to 0.1 μm.

However, the above conventional Co-Ni/C
Both R-alloy thin film recording media and Co-Cr thin film recording media have problems with durability, so a protective film 5 (several tens of nanometers) must be formed on the thin film surface to ensure reliability. Therefore, the problem remains that the spacing loss inevitably increases.

Furthermore, in the case of a fixed magnetic disk, since the magnetic disk is rotated at high speed (3600 revolutions/minute), it is very important for the magnetic layer to have high hardness in order to ensure reliability. However, alloys such as Co--Cr thin films inevitably have problems in terms of hardness.

The present invention solves the above problems and provides a method for manufacturing a fixed magnetic disk having perpendicular magnetic recording components that is highly reliable and compatible with high-density magnetic recording. be.

0012

[Means for Solving the Problems] In order to achieve the above object, the present invention forms an oxide thin film having a (100) preferentially oriented NaCl type crystal structure on a disk substrate, and forms a spinel type crystal on the oxide thin film. A fixed magnetic disk with a structure in which an iron oxide soft magnetic thin film and an iron oxide film with a spinel crystal structure containing cobalt having a columnar structure are formed on top of the iron oxide soft magnetic thin film is manufactured by a manufacturing method that utilizes plasma activation and CVD reaction. It is equipped with the following configuration.

[0013]

[Function] Therefore, according to the present invention, since ozone, N20, and water vapor used as reaction gases generate active radicals in plasma, the fixing device has excellent reliability such as durability and hardness, and is capable of high-density magnetic recording. Magnetic disks can be manufactured relatively easily and at low temperatures.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a fixed magnetic disk by plasma CVD according to an embodiment of the present invention will be described below with reference to the drawings.

(Example 1) (FIG. 1) shows the structure of a fixed magnetic disk manufactured by the manufacturing method of the present invention. In the figure, 7 is a disk substrate, 8 is a NiO film, and 9 is an Mn-Zn ferrite. Film, 10 is Co ferrite film, 1
1 is a lubricating layer.

(FIG. 2) shows a schematic diagram of a plasma CVD apparatus in an embodiment of the present invention.

In (FIG. 2), 12 is a reaction chamber;
13 is an electrode, 14 is an exhaust system for keeping the inside of the reaction chamber at low pressure, 15 is a high frequency power source (13.56 MHz),
16, 17, 18, 19, and 20 are vaporizers containing raw materials; 21, 22, 23, 24, and 25 are valves for controlling whether or not carrier gas is introduced into the vaporizer;
7, 28, 29, and 30 are valves for controlling whether or not source gas and carrier gas are introduced into the reaction chamber;
31 is a nitrogen cylinder, 32 is an oxygen cylinder, 33 is an ozonizer, 34 is a N2O cylinder, 35 is a vaporizer containing water,
36 is a substrate heater equipped with a substrate rotation mechanism, and 37 is a base substrate (glass disk substrate). Starting materials include iron acetylacetonate [Fe(C5H7O2)
3], Nickel acetylacetonate [Ni(C5H7
O2)2.2H2O], manganese acetylacetonate [Mn(C5H7O2)2.2H2O], zinc acetylacetonate [Zn(C5H7O2)2.H2O], cobalt acetylacetonate [Co(C5H7O2) 3
] was used.

Nickel acetylacetonate that has been dehydrated (in air at 100° C. for 2 hours) is placed in the vaporizer 16, and manganese acetylacetonate that has been dehydrated is placed in the vaporizer 17.
Add dehydrated zinc acetylacetonate to 18, cobalt acetylacetonate to 19, and iron acetylacetonate to 20, and heat to 185°C and 190°C, respectively.
, 70°C, 120°C, and 135°C and hold. Open the valves 21 and 26 and turn on the nitrogen carrier (flow rate 20SC).
CM) and nickel acetylacetonate vapor are introduced into the reaction chamber 12, which is depressurized by the exhaust system 14, together with ozone (flow rate: 10 SCCM) generated by the ozonizer 33 as a reaction gas, to generate plasma (power: 1 .5W/cm2) and under reduced pressure (0.1W/cm2) for 4 minutes.
7 Torr), a NiO film was formed on a glass disk substrate heated to 350° C. (120 revolutions/min), and valves 21 and 26 were closed.

Subsequently, without breaking the vacuum, the valves 22, 2
3, 25, 27, 28, and 30, and nitrogen carrier (flow rate 8SCCM on the vaporizer 17 side, flow rate 4S on the vaporizer 18 side).
Manganese acetylacetonate vapor, zinc acetylacetonate vapor, and iron acetylacetonate vapor are supplied to the vaporizer 20 side as reactive gases, such as ozone (
With a flow rate of 5 SCCM), the gas was introduced into the reaction chamber 12 which was depressurized by the exhaust system 14, plasma was generated (power: 1.5 W/cm2), and the temperature was maintained under reduced pressure (0.12 T) for 6 minutes.
orr), a Mn-Zn ferrite film was formed, and the valves 22, 23, 27, and 28 were closed.

Further, without breaking the vacuum, valve 2 is
4 and 29 were opened, cobalt acetylacetonate vapor and iron acetylacetonate vapor were introduced into the reaction chamber 12 together with a carrier gas (flow rate 7 SCCM), and a plasma (power 1.5 W/cm2) was introduced into the reaction chamber 12. ) for 9 minutes under reduced pressure (0.09 Torr), and the Mn-Zn
A Co ferrite film was formed on the ferrite film to produce a three-layer film of Co ferrite/Mn-Zn ferrite/NiO.

Then, the glass disk substrate on which the two-layer film was formed was taken out from the vacuum chamber, and the same three-layer film was formed on the back side using the same method, and a C.
An o-ferrite/Mn-Zn ferrite/NiO disk was produced.

Next, this disk was heat-treated in air at 300° C. for 3 hours, and then submerged in a liquid bath containing a fluorocarbon organic lubricant and coated to make a fixed magnetic disk (A type). Created.

The manufactured fixed magnetic disk (type A) of the present invention was manufactured using an MIG head having a gap length (GL) of 0.25 μm and a track width (Tw) of 10 μm.
The head current value of A was selected to evaluate the electromagnetic conversion characteristics. A fixed magnetic disk (type A) was rotated at a speed of 3600 revolutions/minute, and evaluation was performed on a circumferential track 20.0 mm from the center of the disk. Note that fixed magnetic disks (A
type) and the magnetic head is 7.5 m/sec.
The flying height of the magnetic head is 0.15 μm.
Met.

Next, for comparison, Hc=1000Oe
So, when Ms=800emu/cc, the magnetic layer thickness is 80nm.
A conventional Co-N film was formed with a carbon film of 60 nm thick as a protective layer thereon, and a lubricant film layer similar to that of the present invention was provided.
A fixed magnetic disk (B type) of i/Cr alloy thin film (aluminum substrate with magnetization oriented in the in-plane direction) and Co ferrite were prepared using oxygen as a reactive gas under the same conditions as the present invention (substrate temperature 350°C). /Mn-Zn ferrite/NiO disk (fixed magnetic disk (C type)) was produced, and its electromagnetic conversion characteristics were evaluated under the same conditions as the fixed magnetic disk (A type) of the present invention.

The obtained fixed magnetic disk (A type) produced by the manufacturing method of the present invention, the Co-Ni/Cr alloy thin film fixed magnetic disk (B type), and the fixed magnetic disk (C Figure 3 shows the relationship between recording density and playback output for the following types.

In FIG. 3, the horizontal axis represents the recording density (recording wavelength), and the vertical axis represents the reproduction output. In addition, (a) is a fixed magnetic disk (A type) manufactured by the manufacturing method of the present invention, (b)
) shows the characteristics of a Co-Ni/Cr alloy thin film fixed magnetic disk (type B) for comparison, and (c) shows the characteristics of a fixed magnetic disk (type C) for comparison.

From FIG. 3, it can be seen that the fixed magnetic disk (A type) produced by the manufacturing method of the present invention has higher playback than the Co-Ni/Cr alloy thin film fixed magnetic disk (B type) and the fixed magnetic disk (C type). Showed the output.

When the reproduced waveform of the recording signal of the fixed magnetic disk of the present invention was observed with an oscilloscope, it showed a dipulse waveform, which is characterized by containing a perpendicular magnetic recording component.

After the measurement of the electromagnetic conversion characteristics, the lubricating film layer was removed using an organic solvent, and the crystal structures of the fixed magnetic disk (A type) and the fixed magnetic disk (C type) were analyzed by X-ray diffraction. As a result, the fixed magnetic disk (type A) was superior in crystallinity and (100) orientation.

A fixed magnetic disk (type A) was broken and the surface and fracture surface of the disk were observed using a high-resolution scanning electron microscope. As a result, the two-layer film of this disc has a columnar structure, with a film thickness of approximately 440 nm and a column diameter of 5.
It was found to be 0 to 90 nm.

The reason why the fixed magnetic disk (type A) of the present invention exhibits a higher reproduction output than the Co-Ni/Cr alloy thin film fixed magnetic disk (type B) is that it has a perpendicular magnetic recording component. , and because the Mn-Zn ferrite film and Co ferrite film have excellent crystallinity and (100) orientation due to the influence of the NiO film as the underlayer, and because a soft magnetic material is used as the underlayer, Co ferrite This is because the influence of the demagnetizing field is reduced by forming a horseshoe-shaped magnetic path with the magnetic layer. Also, the reason why the playback output shows a higher value than the fixed magnetic disk (C type) is as follows.
The most important reason is thought to be that the use of ozone as a reaction gas provides better crystallinity and (100) orientation than when oxygen is used.

Furthermore, using the same film forming method, a CoO film or a MnO film is used instead of the NiO base film, or a case where a Mn
- Even when a Ni-Zn ferrite film, a Mn ferrite film, a Ni ferrite film, or a Zn ferrite film is used instead of the Zn ferrite base film, the electromagnetic conversion characteristics were evaluated and the results showed that Co ferrite/Mn-Zn ferrite/ Similar to the case of the fixed magnetic disk made of three layers of NiO, the reproduction output was higher than that of the conventional Co--Ni/Cr alloy thin film fixed magnetic disk or the case prepared using only oxygen as the reactive gas.

(Embodiment 2) Hereinafter, a method for manufacturing a fixed magnetic disk by the plasma CVD method according to an embodiment of the present invention will be described with reference to (FIG. 2).

The starting materials include iron acetylacetonate [
Fe(C5H7O2)3], nickel acetylacetonate [Ni(C5H7O2)2.2H2O], manganese acetylacetonate [Mn(C5H7O2)2.2H
2O], zinc acetylacetonate [Zn(C5H7O
2) 2.H2O], cobalt acetylacetonate [C
o(C5H7O2)3] was used.

Nickel acetylacetonate that has been dehydrated (in air at 100°C for 2 hours) is placed in the vaporizer 16, and manganese acetylacetonate that has been dehydrated is placed in the vaporizer 17.
Add dehydrated zinc acetylacetonate to 18, cobalt acetylacetonate to 19, and iron acetylacetonate to 20, and heat to 185°C and 190°C, respectively.
, 70°C, 120°C, and 135°C and hold. Open the valves 21 and 26 and turn on the nitrogen carrier (flow rate 20SC).
CM) and nickel acetylacetonate vapor were introduced into the reaction chamber 12, which was depressurized by the exhaust system 14, together with N2O as a reaction gas (flow rate: 8 SCCM), and plasma was generated (power: 1.5 W/cm2). let me,
The reaction was carried out under reduced pressure (0.17 Torr) for 4 minutes, and 35
Glass disk substrate heated to 0°C (120 revolutions/min)
A NiO film was formed thereon, and the valves 21 and 26 were closed.
Continue to open valves 22, 23, 25, without breaking the vacuum.
27, 28, and 30 were opened, and manganese acetylacetonate vapor and zinc acetylacetonate were added together with nitrogen carrier (flow rate 8SCCM on the vaporizer 17 side, flow rate 4SCCM on the vaporizer 18 side, flow rate 15SCCM on the vaporizer 20 side). The steam of iron acetylacetonate and the steam of iron acetylacetonate are introduced into the reaction chamber 12, which is depressurized by the exhaust system 14, along with N2O (flow rate: 5 SCCM) as a reaction gas, and plasma is generated (power: 1.5 W/cm2). ) for 6 minutes under reduced pressure (
0.12 Torr), a Mn--Zn ferrite film was formed, and the valves 22, 23, 27, and 28 were closed.

Further, without breaking the vacuum, valve 2 is closed.
4 and 29 were opened, cobalt acetylacetonate vapor and iron acetylacetonate vapor were introduced into the reaction chamber 12 together with a carrier gas (flow rate 7 SCCM), and a plasma (power 1.5 W/cm2) was introduced into the reaction chamber 12. ) for 9 minutes under reduced pressure (0.09 Torr), and the Mn-Zn
A Co ferrite film was formed on the ferrite film to produce a three-layer film of Co ferrite/Mn-Zn ferrite/NiO.

Then, the glass disk substrate on which the two-layer film was formed was taken out from the vacuum chamber, and the same three-layer film was formed on the back side using the same method, and a C.
An o-ferrite/Mn-Zn ferrite/NiO disk was produced.

Next, after heat-treating this disk in air at 300°C for 3 hours, the fixed magnetic disk (D type) is coated by submerging it in a liquid bath containing a fluorine-based organic lubricant. Created.

The produced fixed magnetic disk (D type) of the present invention was manufactured using an MIG head having a gap length (GL) of 0.25 μm and a track width (Tw) of 10 μm.
The head current value of A was selected to evaluate the electromagnetic conversion characteristics. A fixed magnetic disk (D type) was rotated at a speed of 3600 revolutions/minute, and evaluation was performed on a circumferential track 20.0 mm from the center of the disk. Note that fixed magnetic disks (D
type) and the magnetic head is 7.5 m/sec.
The flying height of the magnetic head is 0.15 μm.
Met.

The obtained fixed magnetic disk (D type) produced by the manufacturing method of the present invention, the Co-Ni/Cr alloy thin film fixed magnetic disk (B type), and the fixed magnetic disk (C Figure 4 shows the relationship between recording density and playback output for the following types.

In FIG. 4, the horizontal axis represents the recording density (recording wavelength), and the vertical axis represents the reproduction output. In addition, (d) is a fixed magnetic disk (D type) manufactured by the manufacturing method of the present invention, (b)
) shows the characteristics of a Co-Ni/Cr alloy thin film fixed magnetic disk (type B) for comparison, and (c) shows the characteristics of a fixed magnetic disk (type C) for comparison.

From FIG. 4, it can be seen that the fixed magnetic disk (d) produced by the manufacturing method of the present invention includes a Co-Ni/Cr alloy thin film fixed magnetic disk (B type) and a fixed magnetic disk (
It showed higher reproduction output than Type C).

When the reproduced waveform of the recorded signal of the fixed magnetic disk of the present invention was observed with an oscilloscope, it showed a dipulse waveform, which is characterized by containing a perpendicular magnetic recording component.

After the measurement of the electromagnetic conversion characteristics, the lubricating film layer was removed using an organic solvent, and the crystal structure of the fixed magnetic disk (D type) and fixed magnetic disk (C type) was analyzed by X-ray diffraction. As a result, the fixed magnetic disk (D type) was superior in crystallinity and (100) orientation.

A fixed magnetic disk (D type) was broken and the disk surface and fractured surface were observed using a high-resolution scanning electron microscope. As a result, the two-layer film of this disc has a columnar structure, with a film thickness of approximately 450 nm and a column diameter of 5.
It was found to be 0 to 90 nm.

The reason why the fixed magnetic disk of the present invention (D type) exhibits a higher reproduction output than the Co-Ni/Cr alloy thin film fixed magnetic disk (B type) is that it has a perpendicular magnetic recording component. , and because the Mn-Zn ferrite film and Co ferrite film have excellent crystallinity and (100) orientation due to the influence of the NiO film as the underlayer, and because a soft magnetic material is used as the underlayer, Co ferrite This is because the influence of the demagnetizing field is reduced by forming a horseshoe-shaped magnetic path with the magnetic layer. Also, the reason why the playback output shows a higher value than the fixed magnetic disk (C type) is as follows.
The most important reason is thought to be that the use of N2O as the reaction gas provides better crystallinity and (100) orientation than when oxygen is used.

Furthermore, using the same film forming method, a CoO film or a MnO film is used instead of the NiO base film, or a MnO film is used instead of the NiO base film.
- Even when a Ni-Zn ferrite film, a Mn ferrite film, a Ni ferrite film, or a Zn ferrite film is used instead of the Zn ferrite base film, the electromagnetic conversion characteristics were evaluated and the results showed that Co ferrite/Mn-Zn ferrite/ Similar to the case of the fixed magnetic disk made of three layers of NiO, the reproduction output was higher than that of the conventional Co--Ni/Cr alloy thin film fixed magnetic disk or the case prepared using only oxygen as the reactive gas.

(Embodiment 3) A method for manufacturing a fixed magnetic disk by the plasma CVD method and electromagnetic conversion characteristics according to an embodiment of the present invention will be explained with reference to FIG. 2.

Starting materials include iron acetylacetonate [
Fe(C5H7O2)3], nickel acetylacetonate [Ni(C5H7O2)2.2H2O], manganese acetylacetonate [Mn(C5H7O2)2.2H
2O], zinc acetylacetonate [Zn(C5H7O
2) 2.H2O], cobalt acetylacetonate [C
o(C5H7O2)3] was used.

Nickel acetylacetonate that has been dehydrated (in air at 100° C. for 2 hours) is placed in the vaporizer 16, and manganese acetylacetonate that has been dehydrated is placed in the vaporizer 17.
Add dehydrated zinc acetylacetonate to 18, cobalt acetylacetonate to 19, and iron acetylacetonate to 20, and heat to 185°C and 190°C, respectively.
, 70°C, 120°C, and 135°C and hold. Open the valves 21 and 26 and turn on the nitrogen carrier (flow rate 20SC).
CM) and nickel acetylacetonate vapor are introduced into the reaction chamber 12, which is depressurized by the exhaust system 14, along with oxygen (flow rate: 4 SCCM) and water vapor (partial pressure: 0.009 Torr) as reaction gases, and plasma is generated. (power 1.5 W/cm2) and under reduced pressure (
0.18 Torr), a NiO film was formed on a glass disk substrate heated to 350° C. (120 revolutions/min), and valves 21 and 26 were closed.

Subsequently, without breaking the vacuum, the valves 22, 2
3, 25, 27, 28, and 30, and nitrogen carrier (flow rate 8SCCM on the vaporizer 17 side, flow rate 4S on the vaporizer 18 side).
Manganese acetylacetonate vapor, zinc acetylacetonate vapor, and iron acetylacetonate vapor are added to the vaporizer 20 side with oxygen (flow rate: 3 SCCM) and water vapor (flow rate: 3 SCCM) as reaction gases. A partial pressure of 0.007 Torr) was introduced into the reaction chamber 12, which was reduced in pressure by the exhaust system 14, and plasma was generated (power: 1.5 W/cm2) for 6 minutes under reduced pressure (0.007 Torr).
13 Torr), a Mn-Zn ferrite film was formed, and the valves 22, 23, 27, and 28 were closed.

Further, without breaking the vacuum, valve 2 is
4 and 29 were opened, cobalt acetylacetonate vapor and iron acetylacetonate vapor were introduced into the reaction chamber 12 together with a carrier gas (flow rate 7 SCCM), and a plasma (power 1.5 W/cm2) was introduced into the reaction chamber 12. ) for 9 minutes under reduced pressure (0.09 Torr), and the Mn-Zn
A Co ferrite film was formed on the ferrite film to produce a three-layer film of Co ferrite/Mn-Zn ferrite/NiO.

Then, the glass disk substrate on which the two-layer film was formed was taken out from the vacuum chamber, and the same three-layer film was formed on the back side using the same method, and a C.
An o-ferrite/Mn-Zn ferrite/NiO disk was produced.

Next, after heat-treating this disk in air at 300° C. for 3 hours, the fixed magnetic disk (E type) is coated by submerging it in a liquid bath containing a fluorine-based organic lubricant. Created.

The manufactured fixed magnetic disk (E type) of the present invention was manufactured using a MIG head having a gap length (GL) of 0.25 μm and a track width (Tw) of 10 μm.
The head current value of A was selected to evaluate the electromagnetic conversion characteristics. A fixed magnetic disk (E type) was rotated at a speed of 3600 revolutions/minute, and evaluation was performed on a circumferential track 20.0 mm from the center of the disk. Note that fixed magnetic disks (E
type) and the magnetic head is 7.5 m/sec.
The flying height of the magnetic head is 0.15 μm.
Met.

The obtained fixed magnetic disk (E type) produced by the manufacturing method of the present invention, the Co-Ni/Cr alloy thin film fixed magnetic disk (B type), and the fixed magnetic disk (C type) produced using only oxygen as a reaction gas. Figure 5 shows the relationship between recording density and playback output for the following types.

In FIG. 5, the horizontal axis represents the recording density (recording wavelength), and the vertical axis represents the reproduction output. In addition, (e) is a fixed magnetic disk (E type) manufactured by the manufacturing method of the present invention, (b)
) shows the characteristics of a Co-Ni/Cr alloy thin film fixed magnetic disk (type B) for comparison, and (c) shows the characteristics of a fixed magnetic disk (type C) for comparison.

From FIG. 5, it can be seen that the fixed magnetic disk (e) produced by the manufacturing method of the present invention is a Co-Ni/Cr alloy thin film fixed magnetic disk (B type) and a fixed magnetic disk (
It showed higher reproduction output than Type C).

Note that when the reproduced waveform of the recorded signal of the fixed magnetic disk of the present invention was observed with an oscilloscope, it showed a dipulse waveform, which is characterized by containing a perpendicular magnetic recording component.

After the measurement of the electromagnetic conversion characteristics, the lubricating film layer was removed using an organic solvent, and the crystal structure of the fixed magnetic disk (E type) and fixed magnetic disk (C type) was analyzed by X-ray diffraction. As a result, the fixed magnetic disk (E type) was superior in crystallinity and (100) orientation.

A fixed magnetic disk (E type) was broken and the disk surface and fractured surface were observed using a high-resolution scanning electron microscope. As a result, the two-layer film of this disc has a columnar structure, with a film thickness of approximately 420 nm and a column diameter of 5.
It was found to be 0 to 90 nm.

The reason why the fixed magnetic disk of the present invention (E type) exhibits a higher reproduction output than the Co-Ni/Cr alloy thin film fixed magnetic disk (B type) is that it has a perpendicular magnetic recording component. , and because the Mn-Zn ferrite film and Co ferrite film have excellent crystallinity and (100) orientation due to the influence of the NiO film as the underlayer, and because a soft magnetic material is used as the underlayer, Co ferrite This is because the influence of the demagnetizing field is reduced by forming a horseshoe-shaped magnetic path with the magnetic layer. Also, the reason why the playback output shows a higher value than the fixed magnetic disk (C type) is as follows.
The most important reason is thought to be that the use of N2O as the reaction gas provides better crystallinity and (100) orientation than when oxygen is used.

Furthermore, using the same film forming method, a CoO film or a MnO film is used instead of the NiO base film, or a case where a Mn
- Even when a Ni-Zn ferrite film, a Mn ferrite film, a Ni ferrite film, or a Zn ferrite film is used instead of the Zn ferrite base film, the electromagnetic conversion characteristics were evaluated and the results showed that Co ferrite/Mn-Zn ferrite/ Similar to the case of the fixed magnetic disk made of three layers of NiO, the reproduction output was higher than that of the conventional Co--Ni/Cr alloy thin film fixed magnetic disk or the case prepared using only oxygen as the reactive gas.

[0064]

As described above, the present invention forms a (100) oriented oxide film with a NaCl type crystal structure on a disk substrate, and further coats an iron oxide soft magnetic thin film with a spinel type crystal structure thereon. A method for manufacturing a fixed magnetic disk having a structure in which a spinel-type iron oxide magnetic thin film containing Co having a columnar structure is formed, which is highly reliable and enables high recording density.
Because the plasma CVD method uses ozone, N2O, water vapor, and oxygen as reaction gases, three-layer films can be manufactured easily, at relatively low temperatures, and continuously by simply controlling the supply of raw materials. It can be done.

[Brief explanation of drawings]

FIG. 1 is an enlarged view of the main parts of a fixed magnetic disk manufactured by the manufacturing method of the present invention.

FIG. 2 is a schematic diagram of a plasma CVD apparatus used to carry out the manufacturing method of the present invention.

FIG. 3 is a characteristic diagram comparing and showing the relationship between the recording wavelength and reproduction output of the fixed magnetic disk of the present invention.

FIG. 4 is a characteristic diagram comparing and showing the relationship between the recording wavelength and reproduction output of the fixed magnetic disk of the present invention.

FIG. 5 is a characteristic diagram comparing and showing the relationship between the recording wavelength and reproduction output of the fixed magnetic disk of the present invention.

FIG. 6 is an enlarged view of main parts of fixed magnetic disks of a conventional example and an example.

[Explanation of symbols]

1 Aluminum substrate 2 Ni-P plating layer 3 Cr layer 4 Co-Ni magnetic layer 5 Protective layer 6 Lubricant layer 7 Disk board 8 NiO film 9 Mn-Zn ferrite film 10 Co ferrite film 11 Lubricant layer 12 Reaction chamber 13 Electrode 14 Exhaust system 15 High frequency power supply 16 Vaporizer 17 Vaporizer 18 Vaporizer 19 Vaporizer 20 Vaporizer 21 Carrier gas supply valve 22 Carrier gas supply valve 23 Carrier gas supply valve 24 Carrier gas supply valve 25 Carrier gas supply valve 26 Raw material gas supply valve 27 Raw material gas supply valve 28 Raw material gas supply valve 29 Raw material gas supply valve 30 Raw material gas supply valve 31 Nitrogen cylinder 32 Oxygen cylinder 33 Ozonizer 34 N2O cylinder 35 Vaporizer 36　Substrate heating heater 37 Glass disk substrate

Claims (4)

[Claims] Claim 1: A mixed gas of ozone and the vapor of an organometallic compound of any one of an organometallic compound containing nickel, an organometallic compound containing cobalt, and an organometallic compound containing manganese is decomposed using plasma. By reacting, a thin oxide film with an NaCl type crystal structure is chemically deposited on the disk substrate, and an organic metal compound containing zinc, an organometallic compound containing manganese, or an organometallic compound containing nickel is deposited on the oxide thin film. By using plasma to decompose and react a mixed gas of at least one type of organometallic compound vapor, iron-containing organometallic compound vapor, and ozone, a soft magnetic thin film of iron oxide with a spinel crystal structure is chemically produced. Spinel containing cobalt is formed by vapor deposition and further decomposing and reacting a mixed gas of an organometallic compound containing iron, a vapor of an organometallic compound containing cobalt, and ozone on the iron oxide soft magnetic thin film using plasma. A method for manufacturing a fixed magnetic disk, characterized by chemical vapor deposition of an iron oxide thin film having a type crystal structure. 2. A vapor of an organometallic compound selected from the group consisting of an organometallic compound containing nickel, an organometallic compound containing cobalt, and an organometallic compound containing manganese, and N.
By decomposing and reacting a mixed gas of 2O using plasma, a thin oxide film with an NaCl type crystal structure is chemically deposited on the disk substrate, and an organometallic compound containing zinc and manganese is deposited on the oxide thin film. By using plasma to decompose and react a mixed gas of at least one type of organometallic compound, an organometallic compound containing nickel, a vapor of an organometallic compound containing iron, and N2O, An iron oxide soft magnetic thin film having a spinel type crystal structure is deposited by chemical vapor deposition, and a mixed gas of a vapor of an organometallic compound containing iron, a vapor of an organometallic compound containing cobalt, and N2O is applied to the iron oxide soft magnetic thin film using plasma. 1. A method for manufacturing a fixed magnetic disk, which comprises chemically depositing a thin film of iron oxide having a spinel crystal structure containing cobalt by decomposing and reacting the iron oxide with cobalt. [Claim 3] Using plasma, a mixed gas of the vapor of an organometallic compound, water vapor, and oxygen of any one of an organometallic compound containing nickel, an organometallic compound containing cobalt, and an organometallic compound containing manganese is used. By decomposing and reacting, a thin oxide film with an NaCl type crystal structure is chemically deposited on the disk substrate, and an organometallic compound containing zinc, an organometallic compound containing manganese, and an organometallic compound containing nickel are deposited on the oxide thin film. By using plasma to decompose and react the vapor of at least one organometallic compound containing iron, the vapor of an organometallic compound containing iron, and a mixed gas of water vapor and oxygen using plasma, iron oxide soft material with a spinel crystal structure is produced. A magnetic thin film is chemically deposited on the soft magnetic iron oxide film, and a mixed gas of an organometallic compound containing iron, an organometallic compound containing cobalt, water vapor, and oxygen is decomposed and reacted using plasma. A method for manufacturing a fixed magnetic disk, characterized in that a thin film of iron oxide with a spinel crystal structure containing cobalt is deposited by chemical vapor deposition. 4. The organometallic compound containing nickel, the organometallic compound containing zinc, the organometallic compound containing manganese, the organometallic compound containing iron, and the organometallic compound containing cobalt are β-diketone metal complexes. 4. The method of manufacturing a fixed magnetic disk according to claim 1, 2, or 3.