JPS6074609A - Continuous film forming equipment - Google Patents

Abstract

PURPOSE:To enable keeping moderately high temperature without damaging the surface of a film by heat or inuniformity of characteristics by making at least part of a drum where the film is brought into contact with of a bad heat-conductive material which has heat conductivity of a specific value or less at ordinary temperature. CONSTITUTION:The outside of a drum body 21 made of Fe or stainless steel is covered with a bad heat-conductive thin cover layer 22 of heat conductivity 0.1cal/cm.sec.deg or less. The bad heat-conductive materials used for the cover layer 22 are, e.g., oxides or nitrides such as Al2O3, Y2O3 or ZrO2 and fluorine resins of imido resin, ethylene tetrafluoride resin, etc. or glass coating. The first and the second drums 5a, 5b used in a continuous film forming equipment make a continuous film on a film 3. A vertical magnetic recording medium which has exceptionally high coercive force and uniform characteristics can be obtained without damaging the film 3 by heat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for continuously forming a predetermined film on a film, and particularly to a continuous film forming apparatus suitable for manufacturing magnetic recording media.

[Technical background of the invention and its problems] Perpendicular magnetization recording is a method particularly suitable for high-density recording among magnetic recording methods, and has recently attracted much attention. As is well known, perpendicular magnetization recording is a method in which recording is performed by magnetizing a magnetic recording medium in a direction perpendicular to the film surface.The magnetic recording medium used naturally tends to be magnetized in the perpendicular direction, and the coercive force in this direction is large. These characteristics are required. A conventional magnetic recording medium used for this perpendicular magnetization recording (hereinafter referred to as perpendicular magnetic recording medium) is a Co alloy film such as Co--Cr.

Or Co-Cr-M (M=Rh, Pt, etc.)
A device in which an alloy film is used as a recording magnetic film is considered to be promising.

These perpendicular magnetic recording media are generally manufactured by a sputtering method.

Figure 1 shows an example of a continuous film forming apparatus used to continuously form recording magnetic films for perpendicular magnetic recording media. This figure shows an apparatus suitable for forming the above-mentioned alloy film.

In FIG. 1, reference numeral 1 denotes a vacuum chamber, the inside of which is evacuated to a relatively high vacuum during film formation, and then an inert gas such as Ar gas at an appropriate pressure is introduced.

In this vacuum chamber 1, the film 3 sent out from the supply shaft 2 passes through an auxiliary roller 4a and runs along the circumferential surface of the first drum 5a. Sputter target 6a as an acid supply source
The above-mentioned alloy film is formed on the drum 5a by supplying the film forming material from the drum 5a.

The film 3 with the alloy film formed on one side in this way is guided to the second drum 5b via auxiliary rollers 4b and 4c, and on this drum 5b, the sputtering target 6b placed opposite to it as before is removed.・By supplying film-forming materials,
An alloy film is formed on the other surface. Then, the film 3 with the alloy film formed on both sides is wound onto the winding shaft 7 via an auxiliary roller 4d. Note that the auxiliary rollers 4a to 4d may be omitted depending on the device.

The drums 5a and 5b are rotatably supported and rotate as the film 3 travels during film formation.

These drums 5a and 5b are either entirely made of a material with high hardness or are overcoated with a material with high hardness so as not to damage the film 3 surface. Furthermore, the surfaces of these drums are required to have high surface precision.

Due to these requirements, the drums 5a and 5b may be made of stainless steel or other materials, but as shown in FIG.
A structure in which a hard plating layer 13 of Cr or the like is formed through a base layer 12 of u/Ni is common. The drums 5a and 5b are configured to cool or heat the three surfaces of the film as necessary. The drums 5a and 5b configured in this manner have good contact with the three sides of the film due to their material and surface shape, and as a result, good heat conduction between the two sides allows the drums 5a and 5b to have good contact with the three sides of the film during film formation. Temperature rise is kept to a minimum.

By the way, as explained above, a perpendicular magnetic recording medium is required to be easily magnetized in the direction perpendicular to the film surface, that is, to have a large perpendicular magnetic anisotropy, and to have a large coercive force HC in the direction perpendicular to the film surface. Particularly important is Hc, and if it is small, a problem arises in that a sufficient reproduction output cannot be obtained. Normally, Hc is required to be 300 to 1 ooo oe or more. This method)-1c has the property that it strongly depends on the humidity of the substrate at the time of forming the recording magnetic film. If the substrate temperature is low, Hc
The top is small, and as a result, the playback output is also small.

Therefore, in general, an apparatus as shown in FIG. 1, which has a drum and has a structure in which a film is continuously formed on the surface of the drum, which is the base of a perpendicular magnetic recording medium, is used to
When forming a recording magnetic film such as o-Or, it is difficult to obtain a perpendicular magnetic recording medium with a large HCJL because the heat conduction between the drum and the film (substrate) is large.

In addition, when producing perpendicular magnetic recording media using a continuous film forming apparatus using the sputtering method as shown in Figure 1, a large amount of power is input for sputtering, and the effects of plasma and secondary electrons flowing into the film surface are reduced. Although it is possible to obtain a large medium on HC, there are problems with heat damage to films such as PET (polyethylene terephthalate-1~), which generally have low heat resistance.
It is very difficult to form a large film on Hc while taking into account the characteristics of the medium, especially the problem of fluctuations in HC. This phenomenon is particularly noticeable when using magnetron sputtering, which has a significantly higher sputtering speed and is therefore more suitable for production.

On the other hand, there is also a method of heating the drum surface itself, but in this method, the film receives heat continuously while it is in contact with the drum, so it forms a film on a film that is a substrate with low heat resistance such as PET. In this case, it is difficult to heat the film to the extent that an improvement in Hc can be expected due to the risk of thermal damage.

Furthermore, there is a drawback that the increase in the amount of gas emitted from the film tends to cause a decrease in the perpendicular orientation state of the crystals of the recording magnetic film and in the perpendicular magnetic anisotropy.

[Objective of the Invention 1 The object of the present invention is to maintain a film surface as a substrate at a moderately high temperature during film formation without causing thermal damage or non-uniformity of properties, and to provide a method for maintaining a film surface as a substrate at a moderately high temperature during film formation, and to provide a method for maintaining a film surface as a substrate at a moderately high temperature without causing thermal damage or non-uniformity of characteristics, and to provide a method for forming a film on a perpendicular magnetic recording medium, etc. An object of the present invention is to provide a continuous film forming apparatus suitable for manufacturing.

[Summary of the Invention] In order to achieve the above object, the present invention runs a film sent out from a film supply shaft in a vacuum chamber along a drum surface, and continuously supplies a film-formed product onto the film surface on the drum. After forming a continuous film, in a continuous film forming device that winds the film around a film winding shaft, at least the part of the drum that contacts the film has Q, i cal/cm- at room temperature.
It is characterized by being formed of a thermally poor conductor with a thermal conductivity of sea-deg or less. Examples of the above thermally poor conductor include oxides, nitrides, glass, polymer materials, etc., and these can be used alone or in combination of two or more types.

[Effects of the Invention] According to the present invention, since the thermal conductivity of at least the contact surface of the drum with the film is low, the energy flowing into the film due to sputtering etc. during film formation is difficult to escape to the drum side. is maintained at a moderately high temperature. Therefore, when applied to the manufacture of perpendicular magnetic recording media, for example, the coercive force Hc in the direction perpendicular to the film surface can be increased.

In this case, the film is in a high temperature state only when it is being supplied with film-forming material from the film-formed acid supply source provided opposite to it on the drum, and in other conditions it is relatively high. Since the temperature is maintained at a low temperature, there is no risk of damaging the film due to heat, unlike methods that heat the drum itself, and there are no adverse effects, such as when the inflow energy for film formation is increased.

Here, the thermal conductivity of the thermally poor conductor used for the drum is 0,
The reason for limiting it to 1 cal/cm-sea-deg or less is as follows. If the thermal conductivity of the drum is high, for example, if the inflow energy for film formation is increased to the extent that an improvement in Hc-L can be expected, the film and drum may be damaged due to some reason, such as uneven film tension or adhesion of dust. When the contact condition with the drum changes and the film becomes floating from the drum surface, the risk of thermal damage to the film in the floating state increases significantly. Furthermore, the temperature during film formation becomes uneven due to non-uniform contact between the film and the drum, resulting in variations in the properties of the film. In this respect, if at least the contact portion of the drum with the film is formed of a thermally poor conductor, that is, a thermally poor conductor with a thermal conductivity of It has been experimentally confirmed that it is possible to set the temperature of the film at such a temperature that sufficient improvement in Hc, , L can be expected without increasing the inflow energy for film formation.

[Embodiment of the Invention] FIG. 3 shows the structure of a drum (both or one of 58 and 5b in FIG. 1) in a continuous film forming apparatus according to an embodiment of the present invention. This drum is Fe
Alternatively, it has a structure in which a thin coating layer 22 made of a thermally poor conductor having a thermal conductivity of 0.1 cal/am-sec-deg or less is deposited on the outer peripheral surface of a drum base 21 made of stainless steel or the like.

Specific examples of thermally defective conductors used in this coating layer 22 include:
Examples include oxides and nitrides such as AI20a, Y20B, and ZrO2, and the coating layer 22 can be formed by depositing these on the surface of the drum base 21 by a method such as plasma spraying or ion blasting. can. The coating layer 22 may also be coated with imide resin or fluorocarbon resin such as tetrafluoroethylene resin, or may be coated with glass.

Regarding the thickness of the coating layer 22, if it is too thin, the heat shielding effect will be reduced and the intended purpose cannot be achieved, so the appropriate thickness is 1 .mu.m or more, preferably about several tens to several 100 .mu.m.

10- The drum thus constructed is used as the first drum in the continuous film forming apparatus shown in FIG. Second drum 5a.

5b and formed a continuous film on the film 3, the coercive force was 1 without causing any thermal damage to the film 3.
It was possible to obtain a perpendicular magnetic recording medium with -1c higher than the conventional one and with uniform characteristics.

FIG. 4 shows Go-Crllll on the film 3 using the magnetron sputtering method in the continuous film forming apparatus of FIG. 1.
The dependence of the sputtering power on the coercive force HC when continuously forming A and A when a drum having a coating layer made of a thermally poor conductor according to an embodiment of the present invention is used, and when such a coating layer is used. This is a case B in which a drum having the structure described in FIG. 2 is used. However, the feeding speed of the film 3 was varied so that the thickness of the C, o-Cr film remained constant at 0.5 μm with respect to changes in the sputtering power, and the Go
-The saturation magnetization amount of the Cr film is 350 ellu/cta
It was set as 3. As is clear from this figure, when the drum based on one embodiment of the present invention is used, the Hc value can be increased for the same sputtering power compared to the case where the conventional drum is used, and moreover, even when the sputtering power increases, more prominently) lc
It can be seen that the top increases.

This is because in conventional drums with good thermal conductivity, most of the energy flowing into the film due to sputtering is transferred to the drum, but when using a drum based on an embodiment of the present invention coated with a thermally poor conductor, this This is because the energy is blocked by the coating layer, thereby effectively increasing the temperature of the film.

As described above, when the present invention is applied to the production of perpendicular magnetic recording media, it is possible to obtain media with high HC performance.

Note that this invention is not limited to the above-mentioned embodiments, and can be modified in various ways without departing from the gist of the invention. However, in order to obtain a perpendicular magnetic recording medium having a recording magnetic film on only one side, it is sufficient to provide a coating layer on only one drum. Furthermore, although the thermally poor conductor was used in the form of a coating layer in the embodiment, the entire drum may be formed of a similar thermally poor conductor. Furthermore, although FIG. 1 shows a single-chamber type continuous film forming apparatus, the present invention can of course be applied to a multi-chamber type apparatus.

Furthermore, this invention is applicable not only to the production of perpendicular magnetic recording media, but also when forming a film on a film (substrate) with low heat resistance such as PET by sputtering, etc. Since the film does not suffer serious thermal damage such as melting, it can also be applied to film formation for applications other than perpendicular magnetic recording media. In this case, effects such as flattening the curled state of the film can be expected, and since the necessary temperature can be easily given to the film surface even with a small amount of sputtering power, there is no need for power supply equipment with excessive capacity. There are advantages.

[Brief explanation of drawings]

FIG. 1 is a front view schematically showing the configuration of a continuous film forming apparatus to which the present invention can be applied, FIG. 2 is a diagram showing the structure of a conventional drum, and FIG. 3 is an embodiment of the present invention. Figure 13-4 is a diagram showing the configuration of a drum according to an embodiment of the present invention. It is a figure which shows the case where a conventional drum was used and the case where a conventional drum was used. 1... Vacuum layer, 2... Supply shaft, 3... Film,
4a to 4d...Auxiliary roller, 5a, 5b...Drum, 6a. 6b... Sputter target, 7... Winding shaft, 2
1... Drum base, 22... Covering layer consisting of a thermally poor conductor. Applicant's agent Patent attorney Shikihiko Suzushi 14- Figure 2 11 Figure 3 Figure 4' 1 234

Claims (3)

[Claims] (1) The film sent out from the film supply shaft in the vacuum chamber is run along the drum surface, and after forming a continuous film by continuously supplying the film forming material on the drum to the film surface, the film is In a continuous film forming device that winds up on a winding shaft, at least a portion of the drum that contacts the film has a film formation rate of 0.1 cal/aIll-sec-de at room temperature.
A continuous film forming apparatus characterized in that it is formed of a thermally poor conductor having a thermal conductivity of less than g. (2) The continuous film forming apparatus according to claim 1, wherein the thermally poor conductor is made of at least one selected from oxides, nitrides, glass, and polymeric materials. (3) The continuous film forming apparatus according to claim 1, wherein the film is a base of a magnetic recording medium, and the continuous film formed thereon is a recording magnetic film.