JPS58100676A - Vacuum deposition equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for forming thin films in large quantities by a vacuum evaporation method, for example, an apparatus for manufacturing magnetic recording media in the form of metal thin films, in which a refractory material is used as an evaporation source container. The purpose of this invention is to improve the electron beam heating method and to provide a device that can maintain quality and improve the quality of growth.

The increase in the density of magnetic recording has been remarkable, and in response to this demand, magnetic recording media have been made to have higher coercive force, but recently the limit has begun to appear, and magnetic materials with a high saturation magnetic flux density B8 are being used to form the magnetic layer. Attempts to reduce the thickness are being made in various places.

This is what is called a metal tape, and the ferromagnetic particles include conventional γ-Fe2es and improved γ-F.
! The oxide such as 520s is replaced with metal fine particles such as Fe. However, because of the presence of a binder in these materials, the effective ratio of the magnetic layer cannot be increased.

In contrast, a binder-free vapor-deposited tape, in which the magnetic layer is made of a magnetic thin film formed by vapor deposition, has emerged as the ultimate medium and is attracting attention.

This is manufactured by modifying a winding vapor deposition device used for vapor deposition of capacitors, gold thread, silver thread, etc.

FIG. 1 shows the main components of these devices.

A tape-shaped substrate 1 made of a polymeric material is attached to a rotating can 2.
It moves from the feed shaft 3 to the take-up shaft 4 along. Other elements of the winding mechanism are omitted.

The evaporation source container 5 is arranged so as to look into a part of the rotating can 2, and the evaporation material held therein is irradiated with an electron beam 7 generated from an electron gun 6 so that it evaporates at a constant evaporation rate. It is arranged.

A mask 8 limits the angle of incidence of the vapor flow onto the can 2 and is mainly used to control coercive force.

The vacuum chamber 9 is separated into an upper chamber 10 and a lower chamber 11 by a partition wall 12. The lower chamber is exhausted by an exhaust system 13. The exhaust system for the upper chamber 10, the exhaust system for the electron gun 6, the gas introduction system, etc. are not shown.

A substantially similar configuration may be implemented using a cooled rotary belt tracker instead of the rotary can.

When producing a vapor-deposited tape using the apparatus shown in Figure 1, the points that must be taken into account are ensuring that the quality of the vapor-deposited film is stable over repeated vapor deposition, and ensuring that the proportion of the vapor-deposition time in the process is as large as possible. It is a matter of ingenuity.

From this point of view, the biggest obstacle is the problem caused by the evaporation source container as described below.

That is, for mass evaporation, since the water-cooled copper hearth conventionally used in electron beam evaporation is not suitable as an evaporation source container, it has been considered to use a refractory material.

However, refractories are generally regarded as a source of pollution;
If trying to obtain a membrane with high purity, no filtration was used.

As a result of studying the purity of Al2O5 and the structure of a refractory container using the Mu1205 crucible, the present inventor found that there are large differences in its action as a source of contamination depending on how it is used.

FIG. 3 shows the results of investigating the relationship between the number of times the crucible is used and the impurity concentration in the film when using Method B, Method B, and the apparatus according to the present invention. When measuring,
In each round of deposition, 400
A length of 0 m was deposited, a slit was made in the center of the width to a width of 1 inch, and the 100 m length was slit with acid and quantified by atomic absorption spectrometry.

The vapor deposition material used was 99.99% electrolytic cobalt' (r).

Measurements were made at 10 arbitrary positions within 4000 m in the length direction of the tape, and the average value and the irregularities were calculated.

The same confirmation was carried out six times for each of the cases of Method Person, B, and the present invention. The average value of the results is shown in FIG. 3. The difference between each method is
Conditions during transition between multiple depositions.

That is, method 5 is carried out under the condition that the vacuum is broken 20 minutes after the completion of vapor deposition, and method B is carried out under the condition that the vacuum is broken 20 minutes after the completion of vapor deposition.
The experiment was carried out under the condition that the vacuum was broken after cooling for 20 minutes.

In the case of Method B, a considerable improvement was observed compared to Method B, but the practical limit of the crucible is 6 times at most.

Even if the cooling time was increased to 120 minutes or more, no further improvement could be expected, and while the spring time required for vapor deposition was just under 70 minutes, the cooling time was reversed.
Fundamental improvements were needed, and since it was difficult to solve the problem through software, improvements were needed from the equipment perspective.

The present invention has been made in view of the above points, and embodiments thereof will be described below.

FIG. 2 shows an embodiment of the present invention in a cross section taken in the direction of arrow M in FIG.

Note that the same parts as the device shown in Figure 1 are the same -7. Add numbers and omit explanations.

Winding system, i.e. rotating can 2. The feeding shaft 3 and the winding shaft 4 are connected to a base plate 14 and an intermediate plate 15.
It is common to have a double-sided structure. The rotating shaft 3a and the like pass through the base plate 14 and are naturally sealed.

) Exits to the atmosphere and is connected to a motor, etc. (Not shown) The vacuum chamber 9 includes a storage chamber 16 for the evaporation source container 6, which is connected to a part of the lower chamber 11 (also referred to as a deposition chamber).

The lower chamber 11 and the storage chamber 16 can be separated from each other by partitioning them off with a gate valve 17.

The evaporation source container 5 is configured so that it can be moved between the solid line position and the broken line position by the engines 18- and 18-B.

``An exhaust system (not shown) for the storage chamber 16 is provided independently from other exhaust systems. 19 is an electron gun, and 20 is a magnetic field generating coil for deflection scanning. Both are used to keep the evaporation source container 5 made of refractory warm.

The present invention is not limited to electron beam heating, and the present invention can be similarly implemented using radiant heating using a heater. Although not shown,
Needless to say, a vacuum seal is provided between the gate valve 17 and the vacuum chamber 9.

Using the apparatus shown in FIG. 2, vapor deposition was carried out over a length of 4000 m. After the vapor deposition was completed, the gate valve 17 was opened, the evaporation source container 5 was moved to the position shown by the broken line, the gate valve was closed, and 20 K
At the same time, the vacuum on the deposition chamber side is broken to prepare for the next deposition, and after evacuating the deposition chamber, the gate valve 17 is opened again and the evaporation source container 5 is heated. was moved to the solid line position, the gate valve was closed, and the impurity concentration was checked up to 10 times using the procedure of starting vapor deposition. The result is the third
As shown in the figure, it was stable at extremely low concentrations.

This level is comparable to the level of impurities in films obtained in patch-scale deposition machines using water-cooled copper hearths. As described above, since the vapor deposition can be repeated many times, the substantial proportion of the vapor deposition time can be increased.

In the present invention, the refractory forming the evaporation source container 5 is not limited to Mu1205, but may be composed of ZrO2, MgO, etc.
-10flG7[1(3)' can exhibit exactly the same effect. Furthermore, it can be applied regardless of the type of evaporation material, the method of supplying the evaporation material, the shape of the evaporation source container, the cooling mechanism, etc.

Although the above description has been made regarding the folding of a magnetic tape manufacturing apparatus, the present invention is not limited to this, and the present invention can be effectively used when a large amount of vapor deposition is performed with high purity.

As described above, according to the present invention, a high-quality vapor-deposited tape can be manufactured on a mass production scale, and its industrial value is great.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional vacuum evaporation apparatus, FIG. 2 is a cross-sectional view of a vacuum evaporation apparatus according to an embodiment of the present invention, and FIG. 3 is a diagram showing evaporation using the conventional apparatus and the apparatus according to the present invention. FIG. 4 is a diagram showing the relationship between the number of times the crucible is used and the impurity concentration in the deposited film when the method is used. 1... Board, 3... Feeding shaft, 4...
... Winding shaft, 5 ... Evaporation source container, 16
...Storage room, 17...9...-Gate valve, 19...Electron gun. Name of agent: Patent attorney Toshio Nakao and one other person II
I diagram

Claims (1)

[Claims] A storage chamber configured to perform electron beam evaporation on a tape-shaped polymer substrate while winding it up and housing an evaporation source container of a ferromagnetic material while maintaining a vacuum is connected to the evaporation chamber, and the storage chamber is connected to the evaporation chamber. A vacuum evaporation apparatus characterized in that the chamber is equipped with heating means for the evaporation source container.