JPS6320910B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron beam heating type evaporation source container, and an object of the present invention is to improve the practical performance of a large container made of a refractory material.

In recent years, vacuum evaporation technology has made remarkable progress, and evaporation tapes suitable for short wavelength recording have been developed, and some of them have come into practical use. On the other hand, the consumption of magnetic tape is increasing extremely rapidly, and there is a strong desire to improve vapor deposition technology as a mass production technology.

A conventional container is shown in FIGS. 1a and 1b. As shown in the figure, the container 1 has a pool 2 capable of holding molten metal, and its cross-sectional shape is such that the side wall 3 has a taper a and the bottom surface 4 is horizontal, as shown in figure b. It was hot. By the way, if you use such a container to melt 15 kg of Co as the evaporator and use it for evaporation, the refractory container will become larger, so it is common to divide the container into pieces and butt them together. Difficult to hold. In particular, if you try to use it repeatedly, it will become thermally deformed and lose its horizontality.

At this time, due to the high-temperature wettability between the molten metal and the refractory material (oxide, nitride, etc.) that makes up the container,
As the amount of molten metal decreases, the molten metal is unevenly localized at the bottom of the pool, resulting in the inconvenience that the bottom surface of the refractory is exposed.

The present invention aims to solve such problems in the prior art, and embodiments thereof will be described below with reference to the drawings.

As shown in FIG. 2 in an embodiment of the present invention, the bottom surface 4' is formed of a curved surface. Whether the curvature R is one or multiple curvatures is not a determining factor of the present invention, and it is preferable that the tapered portion is connected from the end with a substantially smooth curved surface. Although the taper angles β and γ of the side wall surface 3' may be equal, it is preferable that they be asymmetrical if accelerated electrons from a coaxial type electron gun are used.

This is because it is related to the angular distribution of evaporated atoms, so-called vapor distribution, and plays an important role not only in vapor deposition efficiency but also in magnetic properties in the case of manufacturing magnetic tapes by vapor deposition. As shown in FIG. 3, when the tape base material 5 is rolled up along the circumferential surface of the rotary can 6 for vapor deposition, an asymmetric tape base material 5 is used, in which the taper angles β and γ on the side wall surface 3' of the container are different from each other. is preferred.

That is, when the rotary can 6 rotates in the direction of the arrow A, the substrate 5 moves from the feed shaft 7 to the winding shaft 8, and vapor deposition is performed using vapor restricted by the mask 9.
Tapers β and γ in the side wall surface 3' of the container 11 holding the molten metal 10 heated by the accelerated electrons 9
In this case, an asymmetrical relationship such that β>γ is preferable.

As shown in the experimental example in Figure 4, γ=10°,
15°, 20°, β/γ as a parameter, 3×
Co− in oxygen at 10 ⁻⁵ (Torr) with a minimum angle of incidence of 36 degrees.
Ni (Ni20wt%) was deposited with a coaxial electron beam (30KV,
100KW) The value of the coercive force of a 0.1 μm film deposited by heating and evaporation, normalized by the coercive force when β = γ, is β
>γ is larger than 1. This is because the dent created by the electron beam entering the molten metal at an angle creates an asymmetrical temperature distribution due to the difference in taper, creating a dent that looks like the electron beam is rising vertically, so the vapor flow distribution is not true. It is presumed that because the mass evaporation part moves upward, the crystallinity improves and the coercive force increases.

When a container with the above structure was used as an evaporation source container to melt and hold 8 kg to 22 kg of metal such as Co, Co-Ni, etc., the metal usage rate was increased to 85 to 88%, and the repeated life was also shorter than that of the previous one. It has increased by 5 to 10 times. Note that the usage rate of metal in conventional containers was 60% to 70%.

According to the present invention, as described above, the usage rate of the molten material is high and the durability is extremely excellent.

[Brief explanation of the drawing]

1a and b are respectively a perspective view and a sectional view of a conventional evaporation source container, FIG. 2 is a sectional view of an evaporation source container according to an embodiment of the present invention, and FIG. 3 is a sectional view of the evaporation source container described above. FIG. 4 is a partial cross-sectional view showing the case where the magnetic tape is used in manufacturing a magnetic tape, and FIG. 4 is a characteristic diagram of the normalized holding force with respect to the taper angle ratio. 3, 3'... side wall surface, 4, 4'... bottom surface.

Claims (1)

[Claims] 1 The side wall surface of the storage section has a taper that opens toward the opening side, and the bottom surface of the storage section has a downwardly convex curved surface, and the taper angle on the side where the coaxial electron beam is obliquely incident is greater than the taper angle on the opposite side. An evaporation source container characterized by its large size.