JPS6157908B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a sputtering apparatus for continuously forming a sputtered thin film as a functional thin film on both sides of a film-like substrate.

[Background technology of the invention and its problems]

In recent years, magnetic recording media in which the recording medium layer is formed of a sputtered thin film have appeared. Sputter thin films are usually produced by performing glow discharge in a low-pressure inert gas, causing the cations generated by this discharge to collide with the target, and by this collision, the metal particles ejected from the target are sent to a specified target. It is formed by adhering to the surface of a supporting substrate.
Therefore, if a material with high magnetic recording properties is selected as the target, a good recording medium layer can be formed.

Incidentally, recently there has been a desire for a magnetic recording medium having a recording medium layer formed of a sputtered thin film on both sides of a film-like substrate, and several proposals have been made for sputtering apparatuses capable of manufacturing this magnetic recording medium.

The uniformity of the magnetic properties of the magnetic recording medium layer formed by sputtering depends on the inert gas pressure during sputtering, the distance between the substrate and the target, the sputtering speed, the substrate temperature, etc. Among these, it is important to keep the distance between the substrate and the target and the temperature of the substrate constant.
Taking these points into consideration, a method in which the film-like substrate is held by work rolls is advantageous in order to continuously form sputter thin films on both sides of the film-like substrate. That is, the film-like substrate is cooled by a refrigerant flowing through the inside and is transferred along the outer circumferential surface of a rotationally driven work roll, and the film-like substrate is brought into contact with the outer circumferential surface of the work roll. A spatter thin film is continuously formed on the surface of the exposed area.
In this way, the time that the film-like substrate is in contact with the work roll can be extended, which allows the substrate to be cooled well, and the distance between the substrate and the target can always be kept constant by the work roll. be able to. In this way, when performing sputtering while aligning the film-like substrate along the outer peripheral surface of the work roll and forming sputter thin films on both sides of the film-like substrate, it is not possible to form sputter thin films on both sides at the same time. It is necessary to adopt an order in which a sputter thin film is first formed on one of the surfaces, and then a sputter thin film is formed on the other surface with a time shift. in this case,
When forming a spatter thin film on the other surface,
Since a sputter thin film has already been formed on one surface, there is a risk that the already formed sputter thin film may be easily damaged during the process of forming a sputter thin film on the other surface. Furthermore, when a sputter source is energized, impurities are generally released from the sputter source, and there is a risk that these impurities will adhere to the surface of the substrate. Furthermore, there is a risk that the deposits adhering to the substrate may fall onto the sputtering source and disturb the sputtering conditions. Furthermore, when sputter thin films are formed on both sides, the overall size of the apparatus becomes larger than when sputtered thin films are formed on only one side, but it is desirable to reduce the size of the apparatus as much as possible from the viewpoint of the exhaust system and the like. Naturally, it is also required to improve the sputtering speed.

[Purpose of the invention]

The present invention can satisfy the above-mentioned needs,
It is an object of the present invention to provide a sputtering device that can continuously form high-quality sputtered thin films on both sides of a film-like substrate at a high speed, and can also reduce the size of the entire device.

[Summary of the Invention] The sputtering apparatus according to the present invention has a work roll involved in the process of forming a sputter thin film on one surface of a film-like substrate in the lower stage, and a work roll involved in the process of forming a sputter thin film on the other surface of the film-like substrate. The spatter sources are arranged in two stages with their axes parallel to each other on the upper stage, and each spatter source facing the outer peripheral surface of each work is placed below a horizontal line drawn through the axes of the corresponding work rolls. Further, during sputtering, the film-like substrate is passed through the outer peripheral surface of the work roll located at the lower stage, and then advanced through the outer peripheral surface of the work roll located at the upper stage, and is folded back from the lower side to the upper side. It is characterized by the provision of a guiding mechanism.

〔Effect of the invention〕

With the above configuration, each work roll, supply reel, and take-up reel can be arranged in a nearly circular arrangement, so the entire apparatus can be downsized, and the exhaust system can be downsized.

Furthermore, with the above configuration, the film-like substrate is
First, a sputtered thin film is formed on the lower surface of the lower stage side, and then the sputtered thin film is folded back so as to become the upper surface and travels along the upper work roll, and a sputtered thin film is formed on the lower surface of the upper stage, Eventually, spatter thin films are formed on both sides. When transferring from the lower stage to the upper stage, it is necessary to pass through a relay roll such as a free roll, but the position of this relay roll is necessarily on the side where the sputter thin film is not formed. Therefore, damage to the spatter thin film already formed by the relay roll can be minimized, and products of higher quality can be manufactured. In addition, by arranging each spatter source at an angle with respect to a vertical line drawn through the axis of the corresponding work roll, the spatter source can be positioned obliquely below the facing surface of the base. Therefore, it is possible to prevent the impurities emitted from the sputter source from adhering to the base side, and it is also possible to prevent various foreign substances from adhering to the sputter source, and from this point of view, it is possible to form a high quality spatter thin film. . In addition, if the spatter source is installed at an angle with respect to a vertical line drawn through the axis of the work roll, two or more spatter sources can be generated on one work roll without detracting from the above-mentioned advantages. The sources can be installed facing each other. Therefore, it is possible to increase the sputtering speed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Note that this embodiment is an example in which the present invention is applied to an apparatus for forming magnetic recording medium layers on both sides of a polymer film.

In FIG. 1, reference numeral 1 indicates a vacuum container made of, for example, a metal material, and this vacuum container 1 includes a cylindrical portion 2 whose axis is perpendicular to the direction of gravity, and a cylindrical portion 2 disposed such that its axis is perpendicular to the direction of gravity. It is comprised of lid bodies 3a and 3b (however, 3b is not shown) that airtightly cover the openings at both ends of the lid. The cylindrical portion 2 is formed with an exhaust port 4 communicating with an exhaust system (not shown) and a gas inlet 5 communicating with an inert gas supply system (not shown). Note that the lid body 3b is formed in a structure that can be selectively opened and closed.

Therefore, inside the vacuum container 1, this vacuum container 1
Inside, a guide mechanism 11 is provided which guides the film-like substrate P along a path perpendicular to the axis of the cylindrical portion 2 and along a U-shaped path from bottom to top. This guide mechanism 11 has a supply reel 12 and work rolls 13 and 14 arranged below an imaginary line that divides the vacuum chamber 1 into upper and lower halves from the left to right in the figure, and above the imaginary line that divides the vacuum vessel 1 into upper and lower halves. Work rolls 15 and 16 and a take-up reel 17 are arranged from the right to the left in the figure, and a free roll 18 is arranged between them.
It is made up of. These freerolls 18,
The work rolls 13, 14, 15, 16, the supply reel 12, and the take-up reel 17 are arranged such that their axes are parallel to the axis of the cylindrical portion 2, respectively. Then, the film-like substrate P unwound from the supply reel 12 is transferred to the work roll 1
3, 14, 15, and 16 in this order along the outer circumferential surface of each work roll, and are guided so as to be folded back at the lowest surface position of each work roll, and are finally taken up on the take-up reel 17. Ru.

A drive shaft (not shown) is connected to each of the supply reel 12 and the take-up reel 17, and these drive shafts hermetically maintain the lid 3a insulated from the lid 3a. It is rotatably passed through and connected to the rotating shafts of DC shunt type motors 12a and 17a, respectively indicated by a in FIG. 2. Further, the work rolls 13, 14, 1
5 and 16 are each formed into a double cylinder shape, and these work rolls 13, 14, 15, 16
The drive shafts each have a double cylindrical shape and are connected to each other so that the corresponding spaces communicate with each other. Each of the drive shafts formed in a double cylinder shape passes through the lid 3a airtightly and rotatably with the space between the lid 3a and the lid 3a being insulated. DC shunt type motor 13 shown in
It is connected to the rotating shafts of a, 14a, 15a, and 16a. In addition, heat is applied to the portion of each of the double-cylindrical drive shafts located outside the vacuum vessel 1 through the space located at the center of the drive shaft and into the space located at the center of the work roll. A rotary joint mechanism is provided for feeding a medium and discharging this heat medium to the outside through an outer space in the work roll and an outer space in the drive shaft, and these rotary joint mechanisms are respectively connected to a hot liquid source and a cold liquid source. selectively connected to the source.

In the vacuum vessel 1, there are a total of eight spatter sources 21, 22, two spatter sources 21, 22 facing each other on the outer peripheral surface of each work roll 13, 14, 15, 16.
...28 are arranged. These spatter sources 2
1, 22, . . . , 28 each have a ring-shaped anode arranged concentrically on the outside of a disk-shaped target, insulated from the target, and one magnetic pole surface is in contact with the back surface of the target. It is formed into a magnetron-shaped flat structure with permanent magnets arranged so as to Each spatter source 21, 22, . . . 28 is connected to each work roll 1.
3, 14, 15, and 16, with a vertical line below the horizontal line passing through the axial center line of each work roll and passing through the above-mentioned axial center line as a reference, and this vertical line and the axial center line of the targt The opening angle θ between them is in the range of 30 to 60 degrees, and the opening angles θ are in the range of 30 to 60 degrees. In this embodiment, the targets of the sputter sources 21, 22, 25, 26 are made of permalloy, and the targets of the sputter sources 23, 24, 26 are made of permalloy.
Targets 27 and 28 are made of Co-Cr alloy. And each spatter source 21, 22,...
...28 targets and anodes are each independently connected to the output end of a DC power source (not shown) via lead wires (not shown) that are provided hermetically through the lid 3a.

On the other hand, the supply reel 12 and the work roll 13
, between the work rolls 13 and 14, between the work rolls 14 and 15, between the work rolls 15 and 16, and between the work roll 16 and the take-up reel 17. Tension detectors 31, 32, . . . , 35 are installed to detect tension. These tension detectors 31, 32,
...converts tension into mechanical displacement, for example,
It is configured to output this amount of displacement as an electrical signal. In addition, work rolls 13 and 16
Pinch rollers 37 and 38 are provided on the left side of the figure to selectively press and contact each work roll in conjunction with forward and reverse rotation operations.

Therefore, each of the motors 12a, 13a, 14
a, . . . 17a are independently driven by servo control circuits 41, 42, . These circuits 41, 42, . Configured to control speed. A set speed signal is supplied to the input terminal of each of the servo control circuits 41, 42, . will be introduced.

The speed compensator 53, 54, 55, 56, 57
A circuit 62 calculates the deviation between the tension signal Z ₀ given by the tension setting device 61 and the tension signal Z ₁ obtained by each tension detector, and the speed setting is performed using the deviation signal obtained by this circuit 62. and a circuit 63 for correcting the set speed signal given from the device 51. That is, when Z ₁ is smaller than Z ₀ , the set speed signal is increased by an amount corresponding to the difference between the two, and in the opposite case, the set speed signal is decreased.

Further, the circuit 63 switches the polarity of the increase/decrease signal in response to the forward/reverse rotation switch 52. In this embodiment, the supply reel 12, each work roll 13, 14, 15, 16
The state in which the take-up reel 17 is rotated as shown by the solid line arrow in FIG. 41
A signal corresponding to the low speed setting signal is directly introduced from the signal source 64 to
The output of a tension detector located immediately before the position of the work roll and take-up reel driven by the motor is introduced into servo control circuits 43, 44, 45, and 46 that control the motors a, 15a, 16a, and 17a. The signal passed through the speed corrector is introduced as the set speed signal. In a reversed state, these relationships are switched. Therefore, as shown in FIG. 2, a switch 66 is provided which is switched in conjunction with the switching operation of the forward/reverse rotation switch 52, and FIG. 2 shows the forward rotation state. Reference numeral 68 in the figure indicates a signal source that provides a low speed signal to the servo control circuit 46 during the reverse rotation state. Further, in FIG. 1, reference numerals 70 and 71 indicate holders for holding sputtering sources, 72 indicates a partition plate, and 73 indicates a mask for regulating the area in which a thin film is formed by sputtering.
In addition, the pinch roller 37 is controlled to press and contact the work roll 13 only during normal rotation in response to the switching operation of the forward/reverse rotation switch 52, and the pinch roller 38 is controlled to contact the work roll 13 only during reverse rotation.
It is controlled so that it comes into pressure contact with.

Next, using the apparatus configured as described above, a permalloy layer and a Co-layer are coated on both sides of the film-like substrate P.
An example of use in forming a sputtered thin film with a two-layer structure consisting of a Cr layer will be explained.

First, the lid 3b of the vacuum container 1 is opened, and the take-up reel on which the film-like substrate P is wound is set as shown in FIG. The shaped substrate P is rewound to a predetermined length, and this is rolled back onto each free roll 1 as shown in FIG.
8. After aligning the tension detectors 35, 34, 33, 32, 31 and each work roll 16, 15, 14, 13, wrap the free end around the supply reel 12 and adjust so that a predetermined tension is applied. , lid body 3b
Close. Next, the exhaust system is activated to exhaust the inside of the vacuum container 1 to a sufficiently low pressure. Next, each work roll 1
The high-temperature liquid is delivered to each work roll 13, 1 through drive shafts formed in double cylindrical shapes of 3, 14, 15, and 16.
4, 15, 16, thereby maintaining the surface temperature of each work roll 13, 14, 15, 16 at a predetermined constant high temperature. Next, the forward/reverse rotation switch 52 is switched to the reverse direction. By this switching, each switch 66 is switched to a state opposite to that shown in FIG. In addition, the pinch roller 38
is pressed against the work roll 16 via the film-like base P. Next, the tension setting device 61 outputs a predetermined tension signal Z ₀ and the speed setting device 51 outputs a predetermined set speed signal. In this state,
A starting command S is given to each servo control circuit 41, 42, . . . 46.

When the starting command S is given in this way, each servo control circuit 41, 42, 43, . . . 46 operates, and the motors 12a, 13a, 14a, .
start rotating all at once. That is, the motor 17
a rotates at a low speed determined by the output signal of the signal source 68, and the motor 16a rotates at a low speed determined by the output signal of the signal source 68.
The motors 15a, 14a, 13a, 12a rotate at a speed corresponding to the set speed signal of the speed setter 52,
It rotates at a speed corresponding to the signals corrected in steps 55, 54, and 53. Therefore, the take-up reel 17, the work rolls 16, 15, 14, 13, and the supply reel 12 rotate in the direction opposite to the direction indicated by the solid arrow in FIG.
It is gradually wound onto the supply reel 12 from the take-up reel 17. In this case, each work roll 13, 14,
As mentioned above, since 15 and 16 are kept at a high temperature by the high-temperature liquid, the film-like base P in contact with them is also heated, and as a result, the impurity gas adhering to the film-like base P is released. be done. That is, the film-like substrate P is pretreated by the above-described operation. Note that the reason why the take-up reel 17 is rotated at a low speed is due to inertia.
This is to prevent the windings 7 from rotating too much. Therefore, it is desirable that the signal sources 68 and 64 have output signals that gradually increase as the winding thickness decreases. After performing the pre-processing as described above, each servo control circuit 41, 42, . The supply of the start command S to the take-up reel 1 is thereby stopped.
7. Stop the rotation of each work roll 16, 15, 14, 13 and supply reel 12 to complete the pretreatment process. By this pretreatment step, most of the gas adhering to the film-like substrate P is transferred to the exhaust system and removed.

Next, each work roll 13, 14, 15, 16
The flow of high temperature liquid into the work rolls 13, 14, 15, 16 is then stopped, and then a low temperature liquid of, for example, -15°C is caused to flow into each work roll 13, 14, 15, 16. Each work roll 13, 14, 15,
The surface of 16 is cooled to a sufficiently low temperature.

Next, the forward/reverse rotation switch 52 is operated to switch to the forward rotation side. This switching causes each switch 66 to switch to the state shown in FIG. 2. In addition, the speed setting device 51
and the output of the tension setting device 61 are set to desired values.

In this state, each servo controller 41, 42,...4
A starting command S is given to 6. As a result, the supply reel 12, work rolls 13, 14, 15, 16, and take-up reel 17 start rotating in the direction shown by the solid line arrow in FIG. Start moving to the side. Next, for example, Ar gas is continuously introduced from the gas inlet 5, and in this state, the inside of the vacuum container is
For example, the exhaust system and Ar gas supply system are adjusted to a pressure of 3 to 7 x 10 ^-4 Torr, and then several hundred volts of direct current is applied between the anodes of each sputter source 21, 22...28 and the target. Apply voltage. This application produces a glow discharge between the anode and the target, which, based on well-known principles, knocks out the fine metal particles constituting the target. A part of the metal fine particles that have been knocked out adhere to the surface of the film-like substrate P that travels along the outer peripheral surface of the work roll on the front surface of the target. As mentioned above, the spatter sources 21, 2
The second target is made of permalloy,
Further, the targets of the spatter sources 23 and 24 are Co
-Made of Cr alloy. Therefore, the work roll 1 in which the film-like substrate P is located at the lower stage
3 and 14, a two-layer sputtered thin film layer consisting of a permalloy layer and a Co--Cr layer is formed on one surface of the film-like substrate P. When the film-like substrate P moves along the outer circumferential surface of the work rolls 15 and 16 located at the upper stage, the surface on which the sputter thin film layer has already been formed is the work roll 1.
5 and 16 in contact with the outer peripheral surfaces thereof.
Therefore, when passing through this section, a permalloy layer and a permalloy layer are formed on the other surface of the film-like substrate P.
A sputter thin film layer with a two-layer structure consisting of a Co-Cr layer is formed, and eventually a film-like substrate P with a two-layer structure sputter thin film formed on both sides is wound onto the take-up reel 17. It turns out. Then, when sputtering is performed as described above, the film-like substrate P tends to be heated by this sputtering, but this heat flows through each work roll 13, 14, 15, and 16. transferred to the flowing cryogenic liquid. Therefore, the film-like substrate P will not be thermally damaged. In addition, in the event that the film-like substrate P is stretched due to the above-mentioned heat,
It works like this: That is, when the film-like substrate P stretches as described above, this elongation appears as a decrease in the tension applied to the substrate as it moves between the work rolls. For example, right now, work role 14
When the tension of the substrate traveling between and 15 decreases, this decrease is detected by the tension detector 33. In this way, when the output of the tension detector 33 decreases, the output of the circuit 62 of the speed corrector 55 shown in FIG. 2 increases, and as a result, the output of the circuit 63 also increases. Therefore, since the input to the servo controller 44 increases, the rotational speed of the motor 15a increases, and accordingly, the rotational speed of the work roll 15 increases. Therefore, the winding of the work roll 15 is accelerated by the amount that the tension has decreased, so the tension increases again, and as a result, the work roll 15
The work roll 1 is rotated so that the relative speed difference between the rotational speed of the work roll 15 and the traveling speed of the film-like substrate P traveling along the outer peripheral surface of the work roll 15 becomes almost zero.
5 rotational speed is controlled. Such control is
Other work rolls 14, 16 and take-up reel 1
7 is similarly performed. Therefore, the film-like substrate P is attached to each work roll 14, 15,
16 will always proceed in a very small state. For this reason, especially when traveling along the outer peripheral surfaces of the work rolls 15 and 16,
There is no risk of scratches or the like on the spatter thin film that has already been formed. Further, the cooling performance does not deteriorate, which tends to occur when slip increases.

In this case, especially during sputtering, the film-like substrate P is guided along a path that folds back from the bottom to the top from the lower side to the upper side.
Each element can be placed in a nearly circular arrangement. Therefore, not only the overall size can be reduced, but also the exhaust system can be made smaller. Further, the relay free roll 18 located between the upper and lower stages does not come into contact with the sputtered thin film. Therefore, the sputtered thin film that has already been formed will not be damaged by the relay free roll. In addition, the spatter sources 21, 2
2, 23, . . . 28 are located obliquely below the base surface where they face each other, so impurities from the spatter source will not fall onto the base side, and foreign matter will not adhere to the spatter source. Not at all. Therefore, a high quality sputtered thin film can be formed on both sides. In addition, since the spatter sources are arranged in the above relationship, two or more spatter sources can be opposed to one work roll as shown in the embodiment without detracting from the above-mentioned advantages. As a result, the sputtering speed can be greatly improved, and the above-mentioned effects can be obtained.

In the embodiment described above, the so-called tension control device is composed of a plurality of tension detectors and a plurality of speed compensators that correct the set speed of each work roll drive motor based on the outputs of these detectors. but,
It is not limited to this. That is, the current of the motor that drives each work roll may be detected by a detector, and the speed of each motor may be corrected according to the output of these detectors. Further, when the amount of elongation of the film-like substrate is known in advance, a difference may be set in advance in the set speeds of the respective motors. Further, a weight-type loader may be provided between each work roll to apply a constant load to the film-like substrate moving between the work rolls. Furthermore, during pretreatment, a voltage is applied between each work roll and, for example, a vacuum vessel to generate plasma near each work roll, and this plasma activates the surface of the film-like substrate. This may be used to degas and improve adhesion. In this case, a shutter may be provided between the spatter source and the film-like substrate to prevent impurities from adhering to the spatter source. Further, although the above-mentioned embodiment is an example in which the present invention is applied to a sputter thin film forming device having a two-layer structure, it is of course applicable to a device forming a single-layer structure. Additionally, means for cooling each mask may be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional view of the main parts of a sputtering apparatus according to an embodiment of the present invention, and FIG. 2 is a control circuit diagram of the apparatus. 1... Vacuum container, 12... Supply reel, 17...
...Take-up reel, 13, 14, 15, 16... Work roll, 18... Free roll, 21, 22,
23, 24, 25, 26, 27, 28... Spatter source, 31, 32, 33, 34, 35... Tension detector, 53, 54, 55, 56, 57... Speed compensator, P... Film shaped substrate.

Claims (1)

[Scope of Claims] 1. The film-like substrate unwound from the supply reel is sequentially transferred along the outer peripheral surfaces of a plurality of work rolls, and then wound up with a take-up reel, and the film-like substrate is unwound from the supply reel. In the sputtering device, a sputtering thin film is formed on both sides of the film-like substrate by a sputter source provided opposite to the outer circumferential surface of each of the work rolls before reaching the take-up reel. The work rolls involved in the step of forming a sputter thin film on one surface of the substrate are arranged in a lower row, and the work rolls involved in the step of forming a spatter thin film on the other surface of the substrate are arranged in a two-tier configuration with their axes parallel to each other. At the same time, each sputtering source facing the outer circumferential surface of each of the work rolls is arranged below a horizontal line drawn through the axis of the corresponding work roll, and furthermore, when performing sputtering, the film-like substrate is placed on the lower stage. A sputtering device is provided with a mechanism that guides the sputtering in a folded path from the lower side to the upper side, passing through the outer circumferential surface of the work roll located at the top, and then passing through the outer circumferential surface of the work roll located at the upper stage. . 2. Each of the spatter sources facing the outer circumferential surface of each of the work rolls is arranged at an angle with respect to a vertical line drawn through the axis of the corresponding work roll. The sputtering device according to item 1.