JPS6267729A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To form a vertical magnetic film having high performance by depositing a sputtered ferromagnetic metal on the 1st thin film while maintaining a non-magnetic substrate at a relatively low temp. and epitaxially growing and forming the 2nd thin film thereon. CONSTITUTION:The thin film which has high coercive force and permits the epitaxial crystal growth of the sputtering particles to be deposited at a low temp. on the 1st thin film is formed on said thin film by executing sputtering at the substrate temp. T1 or above in the stage of forming the 1st thin film on the film substrate 1 consisting of PET, etc. having low heat resistance. The ferromagnetic metal is thereafter sputtered on the 1st thin film at the substrate temp. T2 having the relation substrate temp. T2<T1 (T2 is considerably lower than the m.p. of the substrate) and is subjected to the epitaxial crystal growth to form the 2nd thin film. The thermal damage of the substrate is thereby eliminated and the vertically magnetized film having the high performance is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method of manufacturing a perpendicular magnetic recording medium by sputtering, which is suitable for one-time production.

(b) Conventional technology As shown in Fig. 9, KCo-Cr, Co-Cr-Rh
A perpendicularly magnetized film (2) of ferromagnetic metal such as
The perpendicular magnetic recording medium obtained by sputtering on the
It has a large residual magnetic flux density and is suitable for high-density recording.

For example, it has been proposed to apply facing target sputtering and magnetron sputtering as a method for forming a magnetized film such as Co-Cr on a non-magnetic substrate such as a plastic film such as PET, polyamide, or polyimide by high-speed sputtering. ing. (Magazine “Applied Physics Vol. 48 No. 6
Ji+, pages 557 to 561, "Trends in New Sputter Film Forming Technology") FIG. 10 is a schematic diagram of a magnetic tape manufacturing apparatus using a general facing target sputtering method.

In this device, first, the vacuum chamber is sufficiently evacuated, and then Ar
Gas is introduced and the target (
15) When a high negative voltage is applied to (5)' (for example, a Co-Cr alloy plate), Ar gas is ionized and plasma discharge occurs. When these positively charged Ar ions collide with the target, particles on the target surface are sputtered and the non-magnetic substrate (
A magnetized film of Co--Cr or the like is formed on lj. And part of the phase of the can roller (6) can be masked (9)
When the angle of incidence of the sputtered metal on the non-magnetic substrate (1), which is coated with and guided by a can roller (6) to be contracted and retracted, is controlled, a perpendicularly magnetized film is formed on the substrate.

In FIG. 10, () indicates a supply roller, (8) indicates a take-up roller, and 101 (+01 I/i7'' magnet for lasma convergence).

Limiting the initial incident angle θi of sputtered particles deposited on the nonmagnetic substrate +11 to a certain value or less is essential for forming a high-performance perpendicularly magnetized film.

On the other hand, if the initial incident angle θi is made small, the sputtered metal (
This poses a problem in that the rate of deposition of particles (particles) on the non-magnetic substrate deteriorates, resulting in a significant drop in mass production efficiency.

In addition, the can roller (6) is heated and the non-magnetic substrate +13'
Maintaining the temperature at a high temperature is essential for forming a perpendicularly magnetized film with high coercive force thereon.

On the other hand, heating the non-magnetic substrate above a certain temperature may cause thermal damage to substrates with low heat resistance such as PET film, and may cause heat damage to substrates with low heat resistance such as PET film.
Even in the case of a heat-resistant substrate, there remains the problem that the substrate itself wrinkles during formation of a magnetized film, making it difficult to form a perpendicularly magnetized film.

(c) Problems to be Solved by the Invention The present invention provides a high-performance vertical U! The present invention provides a method for mass-producing magnetic recording bodies with good efficiency.

) Means for solving the problem A non-magnetic substrate that is transferred at a constant speed is transported at a relatively high i! in(T t
℃ or higher), and a ferromagnetic metal such as Co-Cr is deposited on it by sputtering, exhibiting a high coercive force of at least 7006e, and epitaxial crystals of sputtered particles deposited on it in a later process. While forming a first thin film that enables growth, the ferromagnetic metal sputtered on the first thin film is kept at a relatively low temperature (T1° C. or lower, however, T2 - T1) of the nonmagnetic substrate. epitaxially growing a second thin film; -
~ (E) Effect When forming the first thin film on a film substrate with low heat resistance such as PET, sputtering at a substrate temperature of 11 or higher will cause the film to be deposited on top of it at a low temperature in a later process due to its high coercive force. A thin film is formed that enables epitaxial crystal growth of sputtered particles.

Thereafter, a ferromagnetic metal is sputtered onto the first thin film at a substrate temperature T2 in the relationship of substrate temperature T2 < Tl (T2 is significantly lower than the melting point of the substrate), and crystals are grown in an epitaxial manner to form a second thin film. This eliminates thermal damage to the substrate and forms a high-performance perpendicularly magnetized film.

(f) Examples Experiments that form the basis of the present invention (1) When sputtering Co-Cr onto a polyimide film base using the facing target sputtering apparatus shown in Fig. 10, the initial incident angle θi and the The relationship between the residual magnetization ratio MV/MH of the Co--Cr film formed in the above was measured. Figure 2 shows the measurement results at the initial incident angle θi
The horizontal axis represents the residual magnetization ratio MV/MH, and the vertical axis represents the residual magnetization ratio MV/MH.

As is clear from this figure, the smaller the initial incident angle θi, the
The residual magnetization ratio MY/MH of the Co--Cr film increases. M
Since the condition for a perpendicularly magnetized film is that V/M H is 1 or more, as is clear from Figure 2, to obtain a Co-Cr perpendicularly magnetized film, the initial incident angle θi is limited to within 15°. I understand that it is necessary.

(2) Similarly, when sputtering K and Co-Cr on a polyimide film base using the apparatus shown in FIG. 10, the initial incident angle θi and the C formed on the film base are
The relationship between the deposition efficiency of the o-Cr film was measured. Figure 3 shows the initial incident angle θi (horizontal axis) and Co-Cr film deposition efficiency (vertical axis).
Indicates the relationship between

Due to the structure of the sputtering equipment shown in Figure 10, the initial incident angle θ1 = 4
5 is equivalent to the state in which the can mask (9) is removed.

Here, the deposition efficiency when Camp 2 and Ri (9) were removed was standardized as 1. As can be seen from this figure, when the initial incident angle θ1=15 (ie, MY/MH=1), the deposition efficiency is 0.7. In order to obtain a higher performance Co-Cr perpendicular magnetization film with MV/MH of 1.5 or more (the larger the MV/MH is, the more suitable it is for high magnetization density), the initial incident angle θi is set to 5 from Figure @2. However, in this case, the deposition efficiency decreases to 0.5 or less.

From the above two experiments ++1 (21), in order to form a high-performance perpendicularly magnetized film on a moving non-magnetic substrate by the high-speed sputtering method, it is necessary to reduce the initial incident angle θi of the sputtered particles. As a result, it was found that there is a contradictory factor that reduces the deposition efficiency of the snow ivy particles.

(3) Based on the above experimental results, the present inventors deposited the first thin film @ 1 (Fig. 4) at a small initial incidence when depositing (o-Cr) on the polyimide film base. A first thin film is deposited by sputtering at a corner to form a first thin film with a vertical to horizontal residual magnetization ratio of 1 or more and which enables epitaxial crystal growth. If Δ sputtering is applied to [Fig. 4], the vertical to horizontal residual magnetization ratio will be 1.
The above thin film is formed efficiently, so 1r! Based on the prediction, a first thin film υ of Co-Cr film was formed with various thicknesses at an initial incident angle θi=5, and then a Co-Cr film was further formed on top of it at an initial incident angle θi-45-. 14th when the second thin film □□□ is formed so that the total thickness t is 0.3 m
Film thickness and residual magnetization ratio of all Mica-Cr films M V/M
I sought a relationship with H. Figure 5 shows the thickness of the 14th membrane circle'
The results of experiment (3) are shown with the abscissa axis and the vertical-to-horizontal remanent magnetization ratio M V /M H as the ordinate axis.

From this figure, it can be seen that in order to obtain a Co--Cr film with M V/M H of 1 or more, the thickness of the first thin film should be 0.07 μm or more. When the thickness of the first thin film is 0.1 μm or more, MV/
MI ( has a maximum value of 1.5. If the first thin film is formed with a sufficiently small initial incident angle θi in this way, the crystal grains will easily grow perpendicular to the film surface, and the second N film will be formed on top of it. Even if the initial incident angle θi is made as large as possible, the second thin film is kept on top of the crystal grain layer with good vertical orientation, in order to ensure that the second thin film will grow epitaxially on top of the first thin film. As a result, a film with a large remanent magnetization ratio MV/MH can be obtained.Therefore, the 24th film can be formed with high deposition efficiency, improving the productivity of high-performance perpendicular magnetic recording media.

(4) When performing Co-Crt sputtering on a polyimide film base using the facing target sputtering apparatus shown in Fig. 10, the film substrate temperature and the vertical direction maintenance of the formed Co-Cr film on the film substrate Magnetic force Hc
We measured the relationship between FIG. 6 shows the measurement results with the substrate temperature on the horizontal axis and the vertical coercive force on the vertical axis.

As is clear from this figure, the higher the substrate temperature Ts, the more Co-C
The vertical coercive force HCL of r model increases.

In vertical magnetic recording using a ring head, the perpendicular coercive force Hc is at least 7000 e or more, preferably 10
Since a film of about 000e is required, as is clear from FIG. .

As is clear from these experimental results, in order to form high-performance non-direct magnetization on a moving non-magnetic substrate by the high-speed spacking method, it is necessary to raise the substrate temperature, but high-energy sputtering is Since the substrate temperature further increases due to the deposition of particles, it becomes difficult to form a film on a substrate with low heat resistance such as a PET film.

According to experiments, there was no heat damage or wrinkles on the PET film.
It was confirmed that the substrate temperature at which a film with a thickness of 0.3 μm could be formed was 70° C. or lower.

(6) Based on the above experimental results, the present inventors discovered that PET
When depositing 1cco-(r) on the film base by sputtering, the first thin film 2υ (Fig. 4) is heated to a high substrate temperature Tl.
The first thin film is deposited by sputtering with a thin film thickness, which enables epitaxial crystal growth with a high perpendicular coercive force, and the second thin film n < 4th film is formed at a substrate temperature T2 lower than KT1. Co-C
The film of the first N film when the first thin film of the R film is formed to a thickness of about 100 ml, and the second thin film is further formed on top of it at a substrate temperature of 60° C. and a total thickness of 0.3 μm. Thickness and full thickness Co-C
The relationship between the vertical coercive force HCI of the r film is shown in FIG. 7, where the thickness of the first thin film circle is plotted on the horizontal axis and the vertical coercive force HCJL is plotted on the vertical axis.

From this figure, Hc-L (vertical coercive force) is 10000
To obtain a Go-Cr film of ea degree, the first thin layer II/J1 is used.
! It can be seen that it is sufficient to set l to 0.02 μm or more.0 Next, the first f4 of the Co-Cr film is formed at the substrate 8 degrees T1 = 120°C.
The substrate temperature T2 and the total thickness of the second thin film were formed on the substrate with a total thickness of 0.3 μm at various substrate temperature T2. The relationship between the vertical coercive force Hc↓ of the Co--Cr film was determined.

Figure 8 shows the second thin 114! Substrate temperature T S (support)
2+ is shown on the horizontal axis and the perpendicular/electrical coercive force HcJ- is shown on the vertical axis.

From this figure, in order to obtain a Co-Cr film with HcJ- of 7000e or more, the base Vi temperature T s +2) of the second thin film must be set at 40°C.
It turns out that you can do the above.

According to the above experiment, the substrate temperature at the time of forming the 14th layer was set to 120℃.
℃, film thickness is 0.02 μm or more, $2/1 film substrate a
If jF is so'c and the total thickness is 0.3 μm, the perpendicular coercive force HcJ- will be about 10,000e.

In this way, if the first thin film is made extremely thin by raising the substrate temperature sufficiently, even if the second thin film substrate temperature is lowered, the 24th film will crystallize on top of the first thin film in an epitaxy manner, so that the second thin film will not be affected by the second thin film. A film with high perpendicular coercive force can be obtained.

Since the first thin film is extremely thin, the rise in substrate temperature due to deposition of high-energy sputtered particles is low, and therefore the film can be formed even on films with low heat resistance such as PET without damaging the substrate due to heat.

Manufacturing Apparatus FIG. 1 shows an embodiment of an apparatus for carrying out the manufacturing method of the present invention. This apparatus basically employs a facing target type sputtering apparatus.

In this device, a Co
-Cr facing target roller)
are placed. The PET (da polyimide) film 11) which is wrapped around the surface of each can roller and transferred is fed to the supply row A/171 - can roller (6) - guide roll (river (11) (river (river)). It is transported at a substantially constant speed along the path of can roll + ef - take-up roll (8).

Canrolla! 61 (6 Which side of the PET film is guided (11 is a 3-car can roll guided so that the same side faces the opening side of the sputtering device (S) The incident angle of particles and the film deposition rate can be adjusted using a water-cooled can mask, 91:9, etc. In the embodiment, the supply row A/
(T) side can mask (9) initial incident angle θi (
a) was set to 5, and the initial incident angle θi (b) of the can mask; 9)' on the winding roller (8) side was set to 45.

The temperature of the PET film (non-magnetic substrate) can be arbitrarily set by heating both the can rows A/+61 and +6 with a heater built into the roll and adjusting the roll temperature. In this example, the supply row/
PET film (1) wrapped around L/1711tllI can roller (6) and on which the first thin pattern is formed
The temperature of the PET film m, which was wound around the can roller (6)' on the winding roller αa side and on which the second thin pattern was formed, was set at 60°C.

With this configuration, first, the vacuum chamber was evacuated to 11XIO Torr, and then Ar gas was introduced and the temperature was increased to 2X10-8 Torr.
While moving the PET film at a feed speed of 15 cm/min, the sputtering power density was 10 w/am2.
When a Co-Cr film is formed with a film thickness of 0.3 μm and a good perpendicular magnetization film with a perpendicular coercive force Hc of 10000e, PE
It cannot be formed on the T film without thermal damage and without wrinkles.

According to experiments conducted by the inventors, it has been confirmed that a high-performance Co--Cr perpendicular magnetic recording medium can be manufactured even on a 1# non-thermal substrate such as PET film.

Although the above embodiment describes the case where a Co-Cr film is formed on a plastic film by facing target sputtering, the present invention is not limited to this, and magnetron sputtering can also be used to form a Co-Cr3 Co − other than
It has been found that similar effects can be obtained with perpendicular magnetization such as Cr-Rh.

In the above embodiment, a case was described in which a Co--Cr film was formed on a plastic film by facing target sputtering, but the present invention is not limited to this.
Even with the magnetron sputtering method, carbon other than Co-Cr film
A similar effect can be obtained with a perpendicularly magnetized film such as o-Cr-Rh.

Although the above-mentioned embodiment has been explained by taking as an example a method for manufacturing a perpendicular magnetic stirrup medium, the present invention is not limited thereto, and in that case, it is not necessary to narrow down the incident angle θl of sputtering.

When the present invention is applied to a method for manufacturing perpendicular magnetic recording media, the incident angle σ! at the time of forming the first thin film is required to improve the deposition efficiency of the ferromagnetic metal to be sputtered. It is desirable to open the incident angle θ2 as much as possible when forming the second thin film.

(G) Effects of the Invention According to the present invention, a magnetic layer with high coercive force can be efficiently formed on a film substrate with low thermal properties such as PET, and in particular, high-performance perpendicular magnetic recording with high vertical to horizontal residual magnetic susceptibility can be achieved. It is possible to provide a manufacturing method that is efficient in mass production of media.

[Brief explanation of drawings]

1 to 8 relate to the present invention, FIG. 1 is a schematic diagram of the manufacturing apparatus, FIG. 2 is a diagram showing the relationship between the initial incident angle θi and the residual magnetization ratio of the C0-Cr film, and FIG. Initial incidence angle θi vs. Co
- Figure 't'' shows the interflow of the deposit efficiency ratio of Cr film, !!4 Figure I
i A partial cross-sectional view of the magnetic medium, FIG. 5 is a diagram showing the relationship between the first thin film thickness of Co-Cr vs. G o -Cr dcJl, and M v / MH of the second thin film of the f# film portion, FIG. 6 is a diagram showing the relationship between substrate temperature and holding magnetic force Hc, and Figure 7 is a diagram showing the relationship between substrate temperature and holding magnetic force Hc.
(Thickness of first thin film) vs. C. Fig. 8 is a diagram showing the relationship between the coercive force of -Cr (first thin film and second thin film), and Fig. 8 is a diagram showing the relationship between the substrate temperature of the @2 thin film and the coercive force of Co--Cr. 9 and 10 relate to a conventional example, where FIG. 9 is a partial sectional view of a magnetic recording medium, and FIG. 10 is a schematic diagram of a manufacturing apparatus. (1)...PET film, [) +6+...Gashiro roller, (6) (5)...Opposing targetera), (T1
...supply roller, H...take-up row 7, i9)
・Can mask. Figure 1 Figure 5 (λ) Tomi 111 (Co-Cr) al! ! Thickness (μm) Fig. 6 Fig. 7 ↑ Co-Cr5J1t Nl d Tg-6 (pm) No. 8
Figure 121 #co (: 4'f 7t Ts + 2 + ('C) No. 1 Procedural Amendment (Spontaneous) October 31, 1985 1. Indication of the case 1985 Patent Application No. 209578 2. Invention Name of Manufacturing Method for Magnetic Recording Media 3, Relationship with the Amendment Person Case Patent Application Name (188) Sanyo Electric Co., Ltd. 4, Agent Address 2-18 Keihan Hondori, Moriguchi City, 'I [1. 0゜02μml or above.'' In the same page 9, line 10, ``rO, 1pm or more'' should be corrected to ``0.
05m Lm or more,” he corrected. O Specification, page 12, line 20, "50℃" is changed to "60℃
” he corrected. that's all

Claims (4)

[Claims] (1) In a method for manufacturing a magnetic recording medium in which a ferromagnetic metal film is formed on a non-magnetic substrate by sputtering, the non-magnetic substrate, which is transferred at a constant speed, is kept at a relatively high temperature (T1°C or higher), and Depositing a ferromagnetic metal by sputtering to form a first thin film exhibiting a high coercive force of at least 7000e or more and enabling epitaxial crystal growth of sputtered particles deposited thereon in a later step, and The sputtered ferromagnetic metal is deposited on the first thin film while keeping the temperature of the non-magnetic substrate at a relatively low temperature (T2°C or lower, however, T2<T1), and a second thin film is epitaxially grown. A method for manufacturing a magnetic recording medium. (2) The first thin film is placed at an incident angle of θ1 (however, θ1≧15°)
Then, the second thin film is attached to a thickness of 0.02 μm or more at an incident angle θ.
2. The method of manufacturing a perpendicular magnetic recording medium according to claim 1, wherein the perpendicular magnetic recording medium is deposited at an angle of 2 (θ2≫θ1). (3) The perpendicular magnetic recording medium according to claim 1 or 2, characterized in that a PET film is used as the nonmagnetic substrate, and the temperature T1°C is 100°C and the temperature T2°C is 70°C. Production method. (4) A method for manufacturing a perpendicular magnetic recording medium according to claim 1, 2, or 3, characterized in that a facing target method is adopted for sputtering the ferromagnetic metal.