JPH03215660A - Crucible for vapor deposition of metal - Google Patents

Abstract

PURPOSE:To suppress the wear of a ceramics liner mounted on the inside surface of a crucible in contact with a high-temp. molten metal, improve durability and prevent contamination of the molten metal by coating or lining the above-mentioned ceramics liner with a high melting metal. CONSTITUTION:A metallic rod 28 which is a raw material is supplied into the crucible 12 consisting of copper frames 20, 21 provided with cooling water holes 23, 24 and is irradiated with an electron beam 17, by which the metallic rod is heated and melted. Metal vapor 19 evaporated in such a manner is deposited by evaporation to form a magnetic recording medium, etc. The ceramics liner 25 is internally applied to a part or the whole of the inside surface of the above-mentioned crucible 12 in contact with the high-temp. molten metal 18 to provide heat insulation and to suppress reaction. Further, a coating layer consisting of the high melting metal material or a metal liner 26, such as lining of a sheet, is provided on the above-mentioned ceramics liner 25. Nb, Mo, Ta, W, and the alloys thereof, etc., are adequate as the above-mentioned high melting metal and the coating layer is formed preferably to 10mum to 1mm thickness and the sheet to 0.1 to 5mm. The wear of the ceramics liner 25 is suppressed in this way and the decrease in the evaporation of the metal vapor 19 and the contamination of the molten metal 18 by the splinters thereof are prevented and the durability thereof is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a metal vapor deposition apparatus, and more specifically to an improvement in a crucible for metal vapor deposition, which is preferably used when manufacturing magnetic recording media etc. by a vacuum vapor deposition method. Regarding.

[Conventional technology]

Conventionally, when manufacturing magnetic recording media mainly by vacuum evaporation, a vacuum evaporation apparatus shown in FIG. On the other hand, a magnetic metal is charged into the crucible 12, and an electron gun 1 is inserted into the crucible 12.
Generally, a method is adopted in which a magnetic metal is deposited on the surface of the film base 15 running along the outer circumferential surface of the coating roller 7 by irradiating the magnetic metal with an electron beam 17 from 3 to melt it and generate metal vapor.

The structure of the crucible 12 for metal deposition used in the conventional vacuum deposition apparatus described above is as shown in FIG. 2, for example.
The molten metal 18 melted by the electron beam 17 is coated with a ceramic liner 25 on the inner surface of the crucible 12, which is composed of an upper crucible frame 20 and a lower crucible frame 2l.
is lined with high temperature molten metal 18 (for example, 1700
A structure that suppresses the heat insulation from the heat (up to 1900°C) and the reaction with molten metal is adopted. For this reason, for example,
- As disclosed in Japanese Patent No. 50472, there was a problem in that fine ceramic fragments generated from the ceramic liner 25 floated on the molten metal 18, thereby hindering the evaporation of the metal vapor 19. .

This problem arises particularly at the end of a metal deposition operation, when the molten metal is cooled and solidified, as shown in FIG. When the heating of the molten metal is stopped and the molten metal turns into solidified metal 18', the volume shrinks, and the ceramic liner 25 shrinks in the length direction (shrinkage allowance ΔL) and in the width direction (shrinkage). Substitution ΔW
) occurs. At this time, on the surface where the ceramic liner 25 and the solidifying metal come into contact, as the temperature decreases, tension and sliding action by the outer circumferential surface of the solidified metal 18' occurs, and the inner surface of the ceramic liner 25 is ground as if being scraped. The force acts to produce fine ceramic granular fragments. Therefore, in proportion to the frequency of melting the metal in the crucible 12 (the number of vapor deposition operations), the granular fragments of the ceramic gradually increase and float on the molten metal 18, not only hindering the evaporation of the metal but also preventing the evaporation of the metal. When the metal is melted about 6 to 8 times, the thickness of the ceramic liner 25 is reduced by half, cracks occur, and the ceramic liner 25 no longer fulfills its initial function (insulation and prevention of reaction with molten metal). The problem was that its lifespan was extremely short.

[Problem to be solved by the invention]

As mentioned above, the ceramic liner used to insulate the inner surface of the crucible for metal deposition used in conventional metal deposition equipment and to prevent reaction with the molten metal can be used for several to eight deposition operations, that is, the frequency of melting of the metal in the crucible. Due to the expansion and contraction of the metal as it heats and melts and cools and solidifies, the inner surface of the ceramic liner is scraped away and fine granular fragments are generated, which float on the surface of the molten metal and reduce the amount of metal vapor generated. Otherwise, the thickness of the ceramic liner may be reduced by half, causing cracks and the like, resulting in a reduction in the ceramic liner's insulation effect and reaction suppression effect with the molten metal.

The purpose of the present invention is to solve the above-mentioned problems in the prior art, and to suppress the wear and tear of the ceramic liner used as the lining of the crucible for metal vapor deposition, and to evaporate metal vapor by floating fine granular ceramic fragments. It is an object of the present invention to provide a crucible for metal deposition provided with a highly durable ceramic liner capable of reducing the amount of metal and preventing contamination of molten metal.

[Means to solve the problem]

Ceramic liner materials used for lining crucibles for metal deposition include magnesia (MgO) and alumina (
A112os), zirconia (zrozL calcia (C
Heat-resistant materials such as aO) can be used, but the maximum operating temperature of these materials is about 1700 to 1900°C. On the other hand, alloys used for vapor deposition, such as Co-Ni (80-20%
, weight ratio》The temperature of the molten metal made of the alloy is also at maximum 1900
℃, which means that the above-mentioned heat-resistant materials are used almost at their allowable heat-resistant limit temperature. Therefore, a violent reaction occurs between the surface of the ceramic liner and the molten metal. In order to avoid this reaction and to prevent the wear of the ceramic liner due to the shrinkage force during cooling and solidification of the molten metal, the inventors of the present invention have made extensive studies to increase the surface hardness of the ceramic liner and to improve the smoothness of the surface. It has been found that by increasing the temperature and lowering the coefficient of friction during cold agglomeration of molten metal, the life of the ceramic liner can be significantly extended. In order to improve the surface properties of this ceramic liner, high melting point materials such as metals such as niobium (Nb), molybdenum (Mo), tantalum (Ta), and tungsten (W), or alloys containing these metals as main components, are used. By coating the surface of the ceramic liner with a metal material by vapor deposition or by lining it with a thin plate made of a high-melting point metal material, it is possible to suppress the reaction with the molten metal at high temperatures, and to prevent solidification when the molten metal shrinks when cooled. Since surface scraping of the ceramic liner by the metal can be avoided, the life of the crucible for metal deposition can be significantly extended.

The thickness of the coating layer made of a high melting point metal material that is coated on the surface of the ceramic liner by vapor deposition or other methods is preferably about 10 lm to 1 mm.
If it is less than 104, peeling or thermal deformation will easily occur, and if it exceeds 1 mm, it will take a long time to evaporate, and a large amount of expensive high-melting point metal material will be required, which will increase the number of manufacturing steps and increase costs. Undesirable.

When the surface of the ceramic liner is lined with a thin plate made of a high-melting point metal material, the thickness of the thin plate is 0.1 to 1.
A range of about 5 mm is preferable, and if it is less than 0.1 mm, thermal deformation or peeling will easily occur, and if it exceeds 5 mm, the cost will be high and it is not practical.

The present invention provides a metal deposition crucible that heats and melts metal to generate steam and deposits metal onto a specific substrate.
A ceramic liner coated with a coating layer made of the above-mentioned high-melting point metal material by a method such as vapor deposition is attached to part or all of the inner surface of the crucible that comes into contact with the high-temperature molten metal, or a thin plate made of the high-melting point metal material is attached. A ceramic liner is attached to part or all of the inner surface of the metal deposition crucible that comes into contact with the molten metal.

The metal deposition crucible of the present invention can be applied to all crucibles used for the deposition of various metals, and can be suitably used in commonly used water-cooled steel crucibles or ship-bottom crucibles. can. In the case of a ceramic bottom crucible, a coating layer made of the above-mentioned high-melting point metal material is directly coated on a part or all of the inner surface by a method such as vapor deposition, or a thin plate made of the high-melting point metal material is directly lined. By doing so, the purpose of the present invention can be achieved.

〔Example〕

An embodiment of the present invention will be described below in more detail with reference to the drawings.

(Example 1) FIG. 1 shows an example of the cross-sectional structure of a water-cooled copper crucible of the present invention. In the figure, the molten metal l8 used for vapor deposition is placed on a crucible upper frame 25 with a ceramic liner 25 provided on the inner surface with a metal liner 26 made of a high melting point metal material.
0 and the lower crucible frame 21, and the surface of the molten metal 18 is heated continuously by the electron beam 17 to a temperature higher than the melting point while maintaining it in a high vacuum state. metal vapor from part 19
is generated continuously. When metal vapor 19 is continuously generated, the mass of molten metal 18 decreases over time. The height (H) of the molten metal l8 is maintained constant.

Crucible 12 for metal deposition having the structure described above (length 750×
Width 150 x height 50 mm), a metal liner 26 (a vapor deposited layer of tantalum is formed to a thickness of 200 ρ) is provided on a ceramic liner 25 (magnesia 96% by weight, length 47 x width 44 x thickness 10 mm). Go-Ni (8
0-20% by weight) alloy (melting point: 1460°C),
The metal liner 26 is heated and melted at a temperature of 1,700 to 1,900°C (about 1 hour), held at that temperature for about 2 hours to vapor deposit the metal, and then cooled and solidified (about 1 hour). Ceramic liner 25 with
The lifespan (the number of times until the metal liner 26 is worn out) was determined. As a result, the crucible for metal deposition in this example can withstand more than 30 cycles, and while the lifespan of conventional crucibles is about 5 to 8 cycles, the metal deposition crucible of this example has a long life of about 4 to 6 times or more. We were able to obtain a crucible for vapor deposition.

(Example 2) Instead of the ceramic liner made of magnesia used in Example 1, a ceramic liner made of alumina (≧95% by weight, length 47 x width 44 x thickness 10IIm) was used, and Ta-W ( The life of the ceramic liner was determined in the same manner as in Example 1, except that a metal liner formed of a vapor deposited layer 2001M (90-10% by weight) alloy was used. As a result, the crucible for metal deposition in this example was able to withstand more than 36 cycles, and had a lifespan approximately 5 to 7 times longer than that of conventional crucibles. .

(Example 3) Instead of the magnesia ceramic liner used in Example 1, zirconia (≧92% by weight, length 47 x width 44
A ceramic liner with a thickness of 10 mm was used, and
．． The life of the ceramic liner was determined in the same manner as in Example 1, except that a ceramic liner lined with a metal liner made of a thin tungsten plate with a thickness of 5 mm was used.

As a result, the crucible for metal deposition in this example was able to withstand more than 20 cycles, and the life of the crucible for metal deposition was approximately 3 to 4 times longer than that of the conventional crucible.

In Examples 1 to 3 above, no elemental components from the ceramic liner could be detected in the metal layer deposited on the film substrate, and extremely high quality metal layers were obtained.

〔Effect of the invention〕

As explained in detail above, the crucible for metal deposition using a ceramic liner having a metal liner made of a high melting point metal material according to the present invention has the following effects.

(1) The lifespan of the ceramic liner can be extended by approximately 3 to 7 times compared to conventional crucibles that do not have a metal liner, which improves the operating rate of equipment by approximately 15% or more and reduces the frequency of crucible replacement. Therefore, the workability of vapor deposition is significantly improved.

(2) There are no crushed granular ceramic fragments floating on the surface of the molten metal, and the amount of evaporation of metal vapor increases by about 5 to 20% compared to conventional crucibles, so the film substrate to be deposited is fed. It becomes possible to increase the speed by about 5 to 20%, which improves productivity.

(3) The distribution of the film thickness in the width direction of the metal deposited on the film substrate (width 500 mm) was improved by a maximum of 4 to 10%, and the product yield was able to be improved by 3 to 8%.

(4) Compared to the case of vapor deposition using a conventional crucible, the manufacturing cost can be reduced by at least 10%, and there is no contamination of elemental components from the ceramic liner into the metal layer of the vapor-deposited film substrate. Therefore, high quality products can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the structure of a water-cooled copper crucible illustrated in Example 1 of the present invention, FIG. 2 is a sectional view showing an example of the structure of a conventional water-cooled copper crucible, and FIG. 3 is a sectional view of a conventional water-cooled copper crucible. FIG. 4 is a plan view showing the state of solidified metal in a water-cooled copper crucible, and FIG. 4 is a schematic diagram showing an example of the structure of a conventional vacuum evaporation apparatus. 1... Vacuum chamber 2... Vacuum pump 3...
・Film base unwinding shaft 4...Unwinding roller 5...Enter side centering roller 6...Enter side guide roller 7...Coating roller 8...Outlet side guide roller 9...Outlet centering Roller 10... Winding reroller 11... Film base winding shaft 12... Crucible 13... Electron gun 14...
... Unwind roll film base 15 ... Film base 16 ... Winding roll film 17 ... Electron beam 18' ... Solidified metal lume base 18 ... Molten metal 19 ... Metal vapor 2 liters ...・Crucible lower frame 23...Upper frame cooling water hole 20...Crucible upper frame 22...Tightening bolt 24...Lower frame cooling water hole 25...Ceramic liner 26...Metal liner 2
8... Raw metal rod

Claims (6)

[Claims] 1. In a crucible that heats and melts metal to generate steam and vapor deposits the metal on a specific substrate, a coating layer made of a high-melting point metal material is provided on part or all of the inner surface of the crucible that comes into contact with the high-temperature molten metal. 1. A crucible for metal deposition, characterized in that it is equipped with a ceramic liner lined with a ceramic liner or a thin plate made of a high melting point metal material. 2. In claim 1, the high melting point metal material is N.
1. A crucible for metal deposition, characterized in that it is made of at least one metal or alloy selected from among the simple metals B, Mo, Ta, and W, or alloys having these as main components. 3. 3. The crucible for metal deposition according to claim 1 or 2, wherein the coating layer made of a high-melting point metal material provided on the ceramic liner has a thickness in the range of 10 μm to 1 mm. 4. 3. The crucible for metal deposition according to claim 1 or 2, wherein the thin plate made of a high melting point metal material lining the ceramic liner has a thickness in the range of 0.1 to 5 mm. 5. The crucible for metal deposition according to any one of claims 1 to 4, wherein the crucible for metal deposition is a water-cooled copper crucible or a ship bottom type crucible. 6. A coating layer made of a high-melting point metal material or a thin plate made of a high-melting point metal material according to any one of claims 1 to 4 is applied to the inner surface of a ceramic boat-bottom crucible in contact with a high-temperature molten metal. A crucible for metal deposition, characterized in that it is partially or completely attached.