JPH0323632B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application] The present invention is directed to the use of a roll film on a polymer film substrate.
Regarding the improvement of a thin film forming method in which a thin film is continuously formed in a vacuum using two rolls, a thin film type magnetic recording medium,
It can be applied to the production of thin film functional elements such as transparent conductive films, heat ray reflective films, and electrolyte batteries, and is particularly suitable for thin film magnetic recording media that require a polymer film with a flat surface as a substrate. [Prior Art] As mentioned above, this technique can be applied to many fields, but the following will explain the manufacture of thin-film magnetic recording media as an example. The above-described thin film magnetic recording medium has recently attracted attention as a medium for high-density magnetic recording, and many proposals have already been made. For example, JP-A-54-147010 discloses a vapor-deposited film of Co, and JP-A-58-91 discloses a perpendicularly magnetized film made of a sputtered Co--Cr alloy film. Although the metal film formed by such thin film forming means such as vapor deposition, sputtering, or ion plating has a thickness of 1.5 μm or less, it cannot be used in conventional coated recording media in which the magnetic layer has a thickness of 3 μm or more. shows the performance of However, the thickness of the metal thin film formed is thin,
The surface condition of the substrate (surface irregularities) directly manifests as irregularities in the magnetic film, causing spacing loss and dropouts. Therefore, from the viewpoint of electromagnetic conversion characteristics (reproduction output, errors), it is preferable that the surface condition of the substrate be as smooth as possible. On the other hand, when using a polymer resin film as a substrate, from the viewpoint of handling such as film winding and unwinding, if the film surface is smooth, the mutual slippage between the films will be poor and blocking will occur, resulting in the product being damaged. The surface of the base film must be rough. As described above, thin-film magnetic recording media have a problem in that if an attempt is made to improve the electromagnetic conversion characteristics of the substrate, its handling and running properties deteriorate. [Object of the Invention] The present invention has been made in view of the current situation, and provides a thin film forming method that can stably form a thin film roll-to-roll continuously with good productivity even when using an extremely smooth polymer film as a substrate. The purpose is to [Configuration and operation of the present invention] The above objects are achieved by any of the present inventions. That is, the present invention uses a long polymer film as a substrate, and while the substrate is transferred in a roll-to-roll manner, a thin film is continuously formed in vacuum on the substrate supported by a support. In the method,
This method of forming a thin film is characterized in that the polymer film on the substrate is slit to a width smaller than that capable of stably forming a film, and then transferred to a support to form a thin film. Note that the roll-to-roll method is a transport method in which the substrate is rolled, unwound and transported, and then wound up again into a roll. By the way, the present invention described above has found that even when a polymer film with a very flat surface is used as a substrate, if the width of the film is narrow, it can be handled stably in a vacuum and a stable film can be formed. It is something that That is, when a film with a flat surface was inserted into a vacuum as a base film and a thin film was formed while being continuously transferred, the following problem was discovered. That is, a film with a flat surface has poor adhesion over its entire width to a support such as a cooling roll or cooling plate, and the film cannot withstand the heat received during thin film formation. The adhesion between the film and a support such as a cooling drum or a cooling plate can be improved by applying sufficient tension when transporting the film. However, the wider the film width, the more difficult it is to apply such tension evenly in the width direction.
The tension was not uniform across the width of the film. Such non-uniform tension has given unfavorable results such as wrinkles and fusing due to the heat generated during film formation. Generally, the film shrinks due to the heat received during film formation and tends to shrink in the width direction, but if the tension in the width direction is uneven, the film shrinks unevenly and concentrates in a certain area, so this area It is assumed that wrinkles occur from this. In other words, it is necessary to satisfy the contradictory conditions that it is necessary to lower the tension in order to allow the film to move freely in the lateral direction, but it is necessary to increase the tension in order to improve its adhesion to the cooling drum. It was hot. As a result of intensive studies on these problems, the present invention has found that these problems can be solved as follows. That is, in a thin film forming method in which a long polymer film is used as a substrate and a thin film is continuously formed in a vacuum on a substrate supported by a support while the substrate is transferred in a roll-to-roll manner, It has been found that the problem of wrinkles does not occur if the polymer film is slit to an appropriate width and transferred to form a thin film before being supported on a support. Slitting a polymer film means cutting a wide polymer film in the width direction to divide it into narrow films. This is believed to be because when the film width is narrow, the heat shrinkage of the film in the width direction is performed evenly, thereby suppressing the occurrence of wrinkles in the central portion of the film width. The occurrence of wrinkles depending on the film width can be confirmed by model experiments using long films with various film widths. Regarding the relationship between film width and tension, if the conditions for film formation are kept constant, the narrower the film width and the higher the tension, the less wrinkles will appear. That is, a width that allows stable film formation can be selected depending on the film used. Therefore, the width of the film slit is selected to be less than the width that allows stable film formation. Naturally, when the film is slit, its width becomes narrower, but a narrower film is sufficient depending on the application. In such applications, the film after being formed must undergo a slitting process, but this method has the advantage that the slitting process can be omitted. The film that is slit before contacting the support is a wide film when it is unwound, so it can be wound smoothly, and there is no need to prepare a winding system for each slit film at the time of winding. Since it can be wound into a single roll like a single film, it is possible to form a film with very high productivity. In terms of equipment, it is sufficient to simply incorporate the slit means into conventional equipment. As the slitting means, any known mechanism conventionally used in slitters etc. can be applied as is, such as using a cutting blade or using a laser beam, but the simplest method is to apply a razor blade to the film, for example. Just that is enough. The width of the film to be slit can be determined within the width that can be stably wound and determined based on the width of the original film and the width of the film to be made into the final product, but it should be selected to a width that provides high product usage efficiency. Not even. It is advantageous in terms of production to use a wide film and slit it into multiple strips. When slitting films are transferred while being in contact with a support to form a film, each film contracts and may have minute gaps at the slitting portion. The same deposits as those deposited on the film may accumulate in such gaps, and melting may occur from the edges of the slitting, but such problems can be prevented by placing a mask at the boundary. . In addition, the above-mentioned flexible polymer resin substrate of Honhatsu is made of polyolefins such as polyethylene and polypropylene, polyamides such as nylon 6, polyesters such as polyethylene terephthalate, polyethylene-2,6-naphthalate, and other thermoplastic resin films. is applicable. Among these, polyethylene terephthalate and polyethylene-2,6-naphthalate are preferred because they are low cost and have excellent dimensional stability, surface properties, heat resistance, and mechanical properties. By the way, when this method is applied to a thin film type magnetic recording medium, all known ferromagnetic thin films can be used. In other words, not only evaporated films made of Fe, Ni, Co, and their alloys for longitudinal recording, which have been actively developed, but also perpendicular magnetic recording methods (PTK 1973), which have recently attracted attention due to their high-density recording potential.
The present invention can also be applied to perpendicularly magnetized films made of Co--Cr alloy films with an easy magnetization axis perpendicular to the film surface (see Japanese Patent Publication No. 10764). In particular, when a magnetic recording layer is formed on both sides for the purpose of a flexible disk, running properties cannot be ensured by a back coat like tape, and the present invention is of great significance. In this case, it is possible to increase both the linear recording density and the track density, and the effects of the present invention are remarkable from the viewpoint of dropout (D/o) and running durability. Note that as a means for forming the above-mentioned thin film, conventionally known physical deposition methods such as a vacuum evaporation method, an ion plating method, and a sputtering method can be applied. Among them, the magnetron sputtering method is used because it enables low-temperature film formation and stable perpendicular anisotropic film formation to form the perpendicular magnetic recording layer using polyester as a substrate to obtain a perpendicular magnetic recording medium. Alternatively, the facing target sputtering method disclosed in JP-A-57-158380 and the like is preferred. The details of the present invention described above will be explained based on examples. FIG. 1 is a structural diagram of a facing target sputtering apparatus used in the practice of the present invention. As is clear from the figure, this device was developed in the above-mentioned JP
It has basically the same construction as the opposed target sputtering device known in Japanese Patent No. 158380. That is, in the figure, 10 is a vacuum chamber, 20 is an exhaust system consisting of a vacuum pump etc. for evacuating the vacuum chamber 10, and 30 is a system for introducing a predetermined gas into the vacuum chamber 10 to increase the pressure inside the vacuum chamber 10 to 10 ^-1 to 10. This is a gas introduction system that is set to a predetermined gas pressure of approximately 10 ^-4 Torr. In the vacuum chamber 10, a pair of targets T ₁ and T ₂ are held by target holders 15 and 16 fixed to the side plates 11 and 12 of the vacuum chamber 10 via insulating members 13 and 14 as shown in the figure. The surfaces T _1S and T _2S to be sputtered are arranged so as to face each other in parallel with a space in between. And target T ₁ ,
T ₂ and its corresponding target holder 15,
16, targets T ₁ , T ₂ , permanent magnets 152 ,
162 is cooled. The magnets 152 and 162 are disposed so that their north and south poles face each other with the targets T ₁ and T ₂ in between, so that the magnetic field is directed towards the targets T 1 and T ₂ .
Formed only in the direction perpendicular to T ₂ and between targets. Note that 17 and 18 are insulating members 13 and 1
This shield is used to protect the target holders 15 and 16 from plasma particles during sputtering, and to prevent further discharge on parts other than the target surface. Further, a substrate holding means 41 for holding the substrate 40 on which the magnetic thin film is formed is provided on the sides of the targets T ₁ and T ₂ in the vacuum chamber 10, and the substrate holding means 41 holds the substrate 40 on which the magnetic thin film is formed.
0 is transferred roll-to-roll. The substrate holding means 41 includes a feed roll 41a and a support roll 41, which are supported rotatably and parallel to each other by support brackets (not shown).
Consisting of three rolls: b, take-up roll 41c,
The substrate 40 is disposed so as to be held substantially perpendicular to the sputtering surfaces T _1S and T _2S so as to face the space between the targets T ₁ and T ₂ . Therefore, the substrate 4
0 is the sputtered surface T _1S by the winding roll 41c,
It is movable in the direction perpendicular to T _2S . In addition,
The surface temperature of the support roll 41b is adjustable in order to control the temperature of the substrate 40. On the other hand, the high-power means 50 consisting of a DC power source for supplying sputtering power has its positive side connected to ground and its negative side connected to targets T ₁ and T ₂ , respectively. Therefore, the sputter power from the power supply means 50 is supplied between the anode and the cathode, with the ground as the anode and the targets T ₁ and T ₂ as the cathodes. In order to protect the substrate 40 during press sputtering, a shutter (not shown) is provided between the substrate 40 and the targets T ₁ and T ₂ to move in and out. As mentioned above, the structure is basically the same as that of the above-mentioned Japanese Patent Application Laid-open No. 57-158380, and as is known, high-speed low-temperature sputtering is possible. That is, in the space between the targets T ₁ and T ₂ , sputter gas ions, γ electrons emitted by the sputter, etc. are bound by the action of the magnetic field and _a high-density plasma is formed _. sputtering is promoted, the amount of precipitation increases from the space, the deposition rate on the substrate 40 increases, high sputtering occurs, and the substrate 4
0 is on the side of the targets T ₁ and T ₂ , low-temperature sputtering is also possible. Note that the opposed target sputtering method of the present invention is not limited to the above-mentioned apparatus;
As mentioned above, this is a sputtering method in which a substrate is placed on the sides of a pair of targets facing each other, and a perpendicular magnetic field is applied between the targets to perform sputtering to form a film on the substrate. Therefore, the magnetic field generating means may also use an electromagnetic field instead of a permanent magnet. Further, the magnetic field may be of any type as long as it confines γ electrons etc. in the space between the targets, and therefore it also includes the case where it is generated not over the entire surface of the target but only around the target. In FIG. 1, the traveling direction (MD) of the substrate 40 is the direction in which the targets T ₁ and T ₂ face each other, that is, the direction in which the permanent magnets 152 and
Magnet φ generated by a magnetic field generator consisting of 162
It will be in almost the same direction as . Furthermore, the thin film forming method of the present invention is not limited to the facing target sputtering method used in the examples, but may also include ordinary physical deposition methods such as magnetron sputtering, vacuum evaporation, bipolar or triple sputtering, and ion plating. Needless to say, the present invention can also be applied to methods such as deposition and chemical deposition methods such as CVD methods. Next, an embodiment of the thin film forming method according to the present invention carried out using the above-mentioned facing target type sputtering apparatus will be described. Examples 1 to 5, Comparative Examples 1 to 5 Permalloy metal (Fe18%wt, Ni78wt%, Mo4wt
%) was formed by a sputtering method using the opposed target sputtering apparatus shown in FIG. The following examples and comparative examples all show film deposition rates.
The temperature of the support drum 41b was 50°C at 0.5 μm/min, and both ends of the film 40 were heated as shown in FIG.
By attaching a 15 mm mask 42a, damage caused by thermal radiation is prevented. Film width 24cm, width of support drum 41b 30cm
I did some sputtering. In the embodiment, as shown in the figure, a slit means 6 using a commonly used razor blade is installed as a cutting tool at a position corresponding to the center portion of the film 40.
The film 40 was divided into two in the width direction by making a notch. The razor blade of the slit means 60 can be moved from outside the vacuum chamber without cutting into the film. In the comparative example, the razor blade was removed from the film and a film was formed under exactly the same conditions as in the example without making any incisions. Sputtering was performed by inputting a power of 8.2kw, changing the film speed, and adjusting the film thickness from 0.1 to 1μ. Film tension is 9.7Kg. The results are shown in Table 1.

[Table] When the film thickness is 0.1μ, wrinkles do not occur regardless of the presence or absence of slits.When the film thickness is 0.3μ or more, wrinkles occur with the film without slits, and when the film thickness is thick, wrinkles do not occur. It turned into a gun and the film melted. Examples 6 to 8 In the examples described above, the film thickness was adjusted by changing the input power. In other words, the film speed is 10cm/
While keeping the input power at min. 1.6kw,
5.0kw, 8.2kw, respectively 0.1μ, 0.3μ,
When we tried to form a 0.5μ film, sputtering was good in all cases, and the desired permalloy thin film could be continuously formed. Examples 9 and 10 and Comparative Examples 6 and 7 In the apparatus shown in Fig. 1, as shown in Fig. 2, a width of 12 mm was applied to the sputter area in the portion corresponding to the slit portion.
Sputtering was performed by applying a mask 42b on the strip to prevent the slit end from being directly exposed to plasma. Turn on the power while keeping the film speed at 10cm.
When film formation was performed by changing the power to 11.5kw and 16.4kw,
In either case, sputtering was performed well without wrinkles, etc., and the desired permalloy thin film could be continuously formed. On the other hand, when sputtering was performed without the mask 42b, the film was fused from the slit portion.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a facing target sputtering device used in carrying out the present invention, and FIG. 2 is a front view of a support drum section. 10: Vacuum chamber, 20: Exhaust system, 30: Gas introduction system, 40: Substrate, 50: Power supply, T ₁ , T ₂ : Target, 42a, 42b: Mask.

Claims (1)

[Claims] 1. A thin film that uses a long polymer film as a substrate and continuously forms a thin film in vacuum on a substrate supported by a support while transferring the substrate in a roll-to-roll manner. A method for forming a thin film, which comprises slitting a polymer film on a substrate to a width below which stable film formation is possible, and transferring the film to a support to form a thin film. 2. The thin film forming method according to claim 1, wherein the front surface of the support corresponding to the slit portion of the substrate is masked. 3. The thin film forming method according to claim 1 or 2, wherein the support is a rotating drum. 4. The thin film forming method according to claim 1, 2 or 3, wherein the thin film is formed by a physical deposition method or a chemical deposition method. 5. The thin film forming method according to claim 1, 2, 3, or 4, wherein the thin film formed is a magnetic recording layer.