JPH0625839A - Sputtering device and cathode - Google Patents

Abstract

PURPOSE:To improve cooling efficiency and to increase the power to be thrown at the time of sputtering by forming ruggedness on the cooling surface of a backing plate holding a target material and increasing the surface area of the cooling surface. CONSTITUTION:The backing plate 190 of a cathode 195 is installed to face a base film B right under a cooling can 87 in a vacuum chamber 81b of the sputtering device and the target material 88 is installed thereon. The rear surface 194 of the backing plate 190 is cooled by cooling water 92 and many pieces of the ruggedness 100 are formed on the cooling surface 194. Many pieces of the ruggedness 100 are formed at >=1mm and <=10mm height of the protruding part 100a and >=1mm and <=30mm periods. As a result, productivity is improved and the target material 92 is stably held.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus and a cathode, and more particularly to a sputtering apparatus and a cathode suitable for forming a protective film on a metal magnetic thin film such as a vapor deposition tape.

[0002]

2. Description of the Related Art In video tape recorders, image quality is being improved by high density recording, and in order to cope with this, a so-called metal magnetic thin film is used as a magnetic layer as a magnetic recording medium for 8 mm VTR, for example. Vapor-deposited tape has been put to practical use.

The vapor-deposited tape is superior in magnetic properties to the widely used coating type magnetic tapes and has a thin magnetic layer, so that it is superior to the coating type magnetic tapes in terms of electromagnetic conversion characteristics. It is expected to perform well.

In order to improve the durability of the metal magnetic thin film in such a vapor deposition tape, it has been conventionally known to provide a protective film by ECR plasma CVD, ion plating, sputtering or the like.

Among the above methods for forming a protective film, an apparatus usable for sputtering is schematically shown in FIG. This sputtering apparatus has a can 87 for guiding and cooling the substrate arranged in the center and vacuum tanks 81a and 81b divided by a partition plate 82, and the vacuum tanks 81a and 81b are respectively evacuated to a vacuum exhaust system 83a. , 83b are connected.

Further, one of the vacuum chambers 81a is provided with a supply roll 84 and a winding roll 85 for the base film B with a metal magnetic thin film, and further the base film B.
Guide rolls 86a, 86b are installed to drive the cooling roller 87 along the cooling can 87.

In the vacuum chamber 81b, a target material 88, such as carbon, is placed as a cathode facing the cooling can 87.
It is installed on the backing plate 90 of 95, and a high frequency voltage (not shown) or a DC voltage is applied between it and the can 87. In this case, a magnetron type sputtering method may be adopted to efficiently concentrate the electrons in the vicinity of the target.

The backing plate 90 of the cathode 95 is
As shown in 15, the target material 88 is a low melting point metal 91 such as solder.
While being adhered and held by, the cooling water 92 is supplied through the pipe 93 to be cooled from the cooling surface 94 by the cooling water.

However, the growth rate of a thin film by sputtering is generally 0.001 to 0.04 μm / min, which is slower than that of vapor deposition or ion plating, and the power density is about 4 w / cm ^{2 at} maximum. Since the required thickness of the protective film is about 0.01 to 0.015 μm, when using the continuous winding type sputtering device as shown in FIG. 14, the conveying speed of the base film B is very slow at about 1 m / min. Becomes
Productivity will be low.

Therefore, it is conceivable to increase the input power to increase the sputtering (film formation) rate. However, if the input power is made too large (at 6 w / cm ² or more), the target material 88 is overheated and the target material 88 is damaged, or the cooling water 92 is insufficiently cooled, and the low melting point metal 91 is overheated. It is melted and the target material 88 slips off. This is likely to occur because the entire cathode including the target material 88 is inclined.
As a result, the target material 88 may come into contact with the cathode electrode material 96, and the discharge may stop.

Therefore, the input power cannot be increased so much, but rather needs to be suppressed. This results in poor efficiency and reduced productivity.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sputtering apparatus and its cathode, which can increase the input power to improve the productivity and can also stably hold the target material.

[0013]

That is, according to the present invention, a cathode having a backing plate for holding a target material is provided facing a support on which a thin film is to be formed by sputtering, and the backing plate is cooled by a cooling medium. In the sputtering apparatus configured as described above, the unevenness is formed on the cooling surface of the backing plate by the coolant, and the surface area of the cooling surface is increased, and the cathode having the above-described configuration Is.

In this device, the height of the protrusions on the cooling surface of the backing plate is 1 mm or more and 10 mm or less, and 1 mm.
As described above, it is desirable that a large number of irregularities be formed in a cycle of 30 mm or less. Further, the coolant supply means can be provided on the cooling surface of the backing plate with the coolant.

Further, the present invention is a sputtering apparatus in which a cathode having a backing plate for holding a target material is provided facing a support on which a thin film is to be formed by sputtering, the target material and the backing. The present invention also provides a sputtering device characterized in that the plate and the cathode are fitted with each other, and the cathode having the above structure.

In each of the above sputtering devices, the target material may be adhered to the backing plate, and the backing plate may be cooled by the coolant supplied by the coolant supply means.

[0017]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 schematically shows a sputtering apparatus for forming a protective film on a vapor deposition tape having a magnetic metal thin film as a magnetic layer. Although this sputtering apparatus has a part in common with the conventional device shown in FIG. 14, the same parts are denoted by common reference numerals and the description thereof will be omitted. However, the cathode itself including the target material 88 is arranged substantially horizontally.

In this embodiment, the structure to be noticed is that the cathode 19 facing the base film B directly below the can 87.
In the structure in which the backing plate 190 of 5 is cooled by the coolant 92 (cooling water), a large number of irregularities 100 as shown in FIGS. 2 and 3 are formed on the cooling surface (back surface) 194 thereof. These irregularities have a relatively round cross-sectional curved shape. Of course, it may be rectangular.

FIG. 2 shows a portion of the cathode 195. Back side (cooling side) of backing plate 190 19
The unevenness 100 formed in 4 is composed of, for example, regularly formed grid-shaped projections 100a and grid-shaped recesses 100b between the grids. The unevenness 100 may be a striped unevenness as shown in FIG. 3B in consideration of the flow of cooling water (refrigerant). The irregularities can be formed by etching by photolithography, laser processing, or cutting processing. The material of the backing plate 190 may be oxygen free copper.

As described above, since the surface area of the cooling surface 194 of the backing plate 190 is increased by forming the large number of irregularities 100, the area of contact with the cooling water 92 is increased and the cooling efficiency (cooling effect) is increased. Can be greatly improved. Therefore, as compared with the conventional example, even if the input power at the time of sputtering is increased, the situation such as damage of the target material 88 or melting of the low melting point metal 91 does not occur, and a thin film (protective film in this example) is formed. It is possible to increase productivity by increasing the growth rate and the transportation speed of the base film.

In order to obtain such an effect more surely, in the above-mentioned unevenness 100, when the height of the convex part 100a is d and the pitch is l, d is 1 mm or more and 10 mm or less l is 1 mm or more and 30 mm It is preferable that d is 1 mm or more and 5 mm or less, and l is more preferably 1 mm or more and 10 mm or less.

If the value of d is too small (the depth of the recess is too shallow), the cooling area that contributes to cooling will be small and the cooling effect will be poor, and the value of d will be too large (the depth of the recess will be too deep. ), The thickness of the backing plate itself becomes too thick as a whole, and the magnetic field on the target surface becomes weak when sputtering by magnetron type sputtering, and the film forming rate decreases. From this viewpoint, it is preferable that the value of d is within the above range.

Further, with respect to l, the period of the unevenness influences the cooling area and affects the uniform cooling effect, so that it is preferable to set it in the above range. That is, if l is too small, the cooling effect is poor (the effect due to the unevenness cannot be exhibited sufficiently), and if l is too large, it is insufficient to increase the area contributing to cooling.

Although the total thickness t of the backing plate is also related to the above d, it is usually preferable that the total thickness t including d is 4 to 16 mm.

At the time of sputtering, the component particles of the target 88 are knocked out by a sputtering gas such as Ar and deposited on the substrate B (actually a metal magnetic thin film). In FIG. 4, substrate B
A state in which a protective film 103 is formed on the upper metal magnetic thin film 102 by sputtering is shown. Examples of the material of the protective film 103 include SiO ₂ , Si ₃ N ₄ , SiNx, BN, ZnO ₂ , carbon and TiN. The thickness of the protective film 103 is preferably 50 Å or more, and is preferably 300 Å or less in terms of spacing loss during reproduction.

The metal magnetic thin film 102 is previously formed by vacuum vapor deposition on the substrate B on which the above-mentioned sputtering is performed, and the apparatus shown in FIG. 5 can be used for this vacuum vapor deposition.

The structure of the upper part of this vacuum vapor deposition system including the cooling can 87 in FIG. 5 may be similar to that of the sputtering system of FIG. Omit it. However, the lower vacuum chamber 81b
An evaporation source 188 is installed in the
A shield plate 198 for controlling the incident angle of the evaporated metal and an oxygen gas introduction pipe 191 for finely and stably depositing vapor deposition particles are provided in the vicinity of the position. The evaporation source 188 is a single metal of iron, cobalt, and nickel, Co-Ni.
An alloy such as a system alloy, a mixture with other elements, or the like can be used. Reference numeral 193 in the figure is a preheating heater.

Therefore, by running the base film B along the cooling can 87 and heating and evaporating the evaporation source 188 by the electron beam 189 from the electron gun 192, the metal magnetic thin film is obliquely vapor-deposited on the base film. It θ min represents the incident angle (minimum value) of the evaporated metal on the base film.

Next, a specific experimental example of the above thin film formation will be described. Each prescription carried out was as follows.

1. Formation of Metallic Magnetic Thin Film In the continuous winding type vapor deposition apparatus shown in FIG. 5, Co ₈₀ Ni ₂₀ was obliquely vapor-deposited under the following conditions in oxygen gas on a polyethylene terephthalate base having a thickness of 10 μm. Degree of vacuum: 1 × 10 ^-4 Torr Incident angle of vaporized metal on the base θmin: 45 ° Oxygen gas introduction rate: 250cc / min Deposition film thickness: 2000Å

2. Formation of Protective Film In the continuous winding type sputtering apparatus shown in FIG. 1, a protective film was formed on the base with the metal magnetic thin film formed above under the following conditions. Sputtering method: DC magnetron sputtering Gas pressure (Ar): 10 mTorr Power density: changed to 18 W / cm ² Protective film thickness: 0.02 μm Target-base distance: 8 cm Target material: Carbon Target diameter: 150 mm × 250 mm (square) Type) Backing plate: As shown in Fig. 1 to Fig. 3 Cooling water temperature: 25 ° C (inlet side)

The base on which the magnetic layer is formed is coated with a back coat made of, for example, carbon and an epoxy binder, and a top coat of a lubricant made of perfluoropolyether, and then cut to a width of 8 mm. Then, a magnetic tape can be created.

In the above, the target temperature (cooling water temperature on the outlet side), the critical input power, and the line speed when d and l of the unevenness formed on the cooling surface of the backing plate and further t were changed were examined. However, the table below
The results shown in 1 were obtained.

[0035]

From the above results, in Comparative Example 1 in which the back surface of the backing plate does not have unevenness, the cooling effect is poor, the input power cannot be increased, and the line speed is low. However, if the backing plate is provided with irregularities according to the present invention, the cooling effect is improved, and particularly d = 1 to 10 m.
It can be seen that the effect becomes large when m and l = 1 to 30 mm (further, t = 8 to 16 mm).

FIG. 6 shows an example in which the unevenness provided on the back surface 194 of the backing plate 190 has a rectangular (cornered) sectional shape, which is different from the example described above.

Also in this example, the above-mentioned d, l, and t are set in the same manner, and a sufficient cooling area can be secured, so that the same effect as described above can be obtained.

7 to 8 show still another embodiment of the present invention. According to this example, the entire cathode including the target material 88 is arranged to be inclined as compared with the example described above, and the back surface 194 of the backing plate 190 is flat but notched (or (Recess) 200 is formed in an annular shape when viewed in plan, and this notch 200
Corresponding to, the target material 88 has a downward protrusion on the periphery.
201 is formed in an annular shape, and the notch 200 of the backing plate 190 and the protrusion 201 of the target material 88 are fitted to each other.

Therefore, the target material 88 is fixed to the backing plate 190 by the low melting point metal 91 in a state where the target material 88 and the backing plate 190 are fitted into each other by projections and depressions.

Since the target material 88 is fitted into the backing plate 190 in a concavo-convex manner as described above, even if the low melting point metal 91 is melted when raising the input power at the time of sputtering, the target material 88 is still attached to the backing plate 190.
Therefore, the discharge does not stop due to the contact with the cathode electrode material 96 due to the locking of the cathode electrode material 96. As a result, the target material can be stably held, and the discharge can be stably performed even if the input power is increased, which greatly improves the productivity.

Next, a concrete experimental example carried out based on this embodiment will be described.

The experimental conditions were the arrangement of the target and cathode shown in FIGS. 7 and 8 (however, the target-base distance was 5 cm, the Ar flow rate was 0.15 l / min), and the other conditions were the same as described above. Each film forming speed was examined. However, the cathode of the comparative example was the one shown in FIG. The results are shown in Table 2 below.
Shown in.

[0044]

From these results, it is possible to increase the input power and increase the film formation rate (improve the transport speed) when the target material is fitted into the backing plate by projections and depressions according to the present invention. Become. In Comparative Example 2, about 0.
The base transfer speed is 1 when forming a protective film of 015 μm.
Although it was about m / min, in the case of Example 11, the base transfer speed could be about 4 m / min.

FIGS. 9 to 12 show other examples of concave and convex fitting of the target material 88 and the backing plate 190. The low melting point metal 91 is not shown.

In the example of FIG. 9, since the recess 200 of the backing plate 190 has a perfect groove shape, the target material 88 is less likely to be displaced, which is considered to be advantageous in terms of stable holding.

FIG. 10 and FIG. 11 each show an example in which concavo-convex fitting is performed at a plurality of places (for example, a ring-shaped portion in the peripheral portion and a central portion). The property is improved.

In the case of FIG. 12, the concavo-convex fitting extends over a relatively wide area at one location and in the central portion, but this still retains the target material well and facilitates attachment to the backing plate. .

FIG. 13 shows still another embodiment of the present invention, which is a structural example in which the example of FIG. 2 and the example of FIG. 8 are combined.

That is, at the same time as providing a large number of irregularities 100 on the back surface of the backing plate 190 in order to improve the cooling efficiency,
The target material 88 is held on the front surface side by concave and convex fitting. Therefore, both the improvement of the cooling effect and the stable retention of the target material can be realized at the same time, so that even if the input power is increased, the low melting point metal cannot be melted, or the input power until the low melting point metal is melted can be increased. Such an effect can be expected.

Although the embodiments of the present invention have been described above, the above-described embodiments can be variously modified based on the technical idea of the present invention.

For example, the uneven shape and pattern of the back surface of the backing plate and the cross-sectional shape and pattern of the uneven fitting on the front surface can be variously changed. Also,
The arrangement of the target material and the cathode is not limited to the above example. The cooling water supply structure, the type of refrigerant (for example, an alcohol-based liquid other than the cooling water can also be used), etc. may be changed. The cooling water does not necessarily have to come into direct contact with the backing plate.

The material of the above-mentioned protective film may be formed as the second magnetic film other than the above-mentioned materials. In addition, the protective film has multiple layers (for example, the lower layer is a corrosion-resistant metal such as Ni,
The upper layer may be carbon, SiO _2, etc.). Note that the present invention is not limited to the protective film and can be applied to the formation of other thin films.

[0055]

As described above, according to the present invention, since the cooling surface of the backing plate is made uneven to increase the surface area, the cooling area by the refrigerant is increased and the cooling efficiency (cooling effect) is greatly improved. be able to. Therefore, even if the input power at the time of sputtering is increased, the damage of the target material and the melting of the low melting point metal do not occur, the growth rate of the thin film is increased, and the transport speed of the base film is improved to improve the productivity. It is possible to raise it.

Further, since the target material is fitted into the backing plate in a concavo-convex manner, even if the low-melting-point metal is melted when increasing the input power during sputtering,
The target material is locked to the backing plate and does not slide down to come into contact with the cathode electrode material to stop the discharge. As a result, the target material can be stably held, and the discharge can be stably performed even if the input power is increased, which greatly improves the productivity.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a sputtering apparatus for forming a protective film according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of a cathode used in the sputtering apparatus.

FIG. 3A is a back view of the backing plate of the cathode.

FIG. 3B is a back view of another cathode backing plate.

FIG. 4 is an enlarged cross-sectional view of a vapor deposition tape.

FIG. 5 is a schematic cross-sectional view of a vacuum vapor deposition apparatus for forming a metal magnetic thin film on the vapor deposition tape.

FIG. 6 is a sectional view of a main part of another example of the cathode.

FIG. 7 is a schematic sectional view of a sputtering apparatus for forming a protective film according to another embodiment of the present invention.

FIG. 8 is a sectional view of a cathode used in the sputtering apparatus.

FIG. 9 is a cross-sectional view of main parts of another example of the cathode.

FIG. 10 is a cross-sectional view of a main part of another example of the cathode.

FIG. 11 is a cross-sectional view of a main part of another example of the cathode.

FIG. 12 is a cross-sectional view of main parts of another example of the cathode.

FIG. 13 is a cross-sectional view of still another example of the cathode.

FIG. 14 is a schematic cross-sectional view of a conventional sputtering apparatus for forming a protective film.

FIG. 15 is a cross-sectional view of a cathode used in the sputtering device.

[Explanation of symbols] 81a, 81b ... Vacuum chamber 82 ... Partition plate 84 ... Supply roll 85 ... Winding roll 87 ... Can 88 ... Target material 90, 190 ... Backing Plate 91 ... Low melting point metal 92 ... Cooling water 94, 194 ... Cooling surface 95, 195 ... Cathode 96 ... Cathode electrode material 100 ... Unevenness 100a ... Convex portion 100b・ ・ ・ Recess 102 ・ ・ ・ Metal magnetic thin film 103 ・ ・ ・ Protective film 188 ・ ・ ・ Evaporation source 189 ・ ・ ・ Electron beam 200 ・ ・ ・ Notch (recess) 201 ・ ・ ・ Projection B ・ ・ ・ Base film (substrate)

Claims (9)

[Claims] 1. A sputter configured such that a cathode having a backing plate for holding a target material is provided facing a support on which a thin film is to be formed by sputtering, and the backing plate is cooled by a cooling medium. In the apparatus, the unevenness is formed on the cooling surface of the backing plate by the coolant, and the surface area of the cooling surface is increased. 2. The apparatus according to claim 1, wherein the cooling surface of the backing plate is provided with a large number of projections and depressions at a height of 1 mm or more and 10 mm or less and a cycle of 1 mm or more and 30 mm or less. 3. The apparatus according to claim 1, wherein the cooling surface of the backing plate with the cooling medium is provided with a cooling medium supply means. 4. A sputtering apparatus provided with a cathode having a backing plate for holding a target material facing a support on which a thin film is to be formed by sputtering, wherein the target material and the backing plate are uneven. A sputtering device characterized by being fitted. 5. The apparatus according to claim 4, wherein the target material is adhered to the backing plate, and the backing plate is cooled by the coolant by the coolant supply means. 6. A cathode having a backing plate for holding a target material, the cathode being provided so as to face a support on which a thin film is to be formed by sputtering, and the backing plate is cooled by a cooling medium. A cathode in which unevenness is formed on a cooling surface of the backing plate by the cooling medium to increase the surface area of the cooling surface. 7. The height of the protrusions on the cooling surface of the backing plate with the refrigerant is 1 mm or more and 10 mm or less, 1 mm or more, 30
7. A large number of irregularities are formed in a cycle of mm or less.
The cathode according to. 8. A cathode having a backing plate which is provided so as to face a support on which a thin film is to be formed by sputtering, and which holds a target material, wherein the target material and the backing plate are fitted in a concavo-convex shape. Configured cathode. 9. The cathode according to claim 8, wherein the target material is adhered to the backing plate, and the backing plate is cooled by the coolant by the coolant supply means.