JPS62139868A - Crucible for electron beam evaporation - Google Patents

Abstract

PURPOSE:To decrease the splashes in the stage of supplying materials and to suppress the change of film compsn. by forming the crucible shape of a hearth for electron beam vapor deposition into an elliptical mortar shape. CONSTITUTION:The crucible 1 of the hearth 2 for electron beam evaporation is formed into the elliptical mortar shape. An evaporation part 3 by electron heating and a material supply part 4 are separated by such shape and the overlap of both parts 3, 4 is decreased to about half the radius or below. The splashes during the supply of the materials for vapor deposition in the long-term continuous evaporation or multi-element alloy vapor deposition of components having differences in vapor pressure and decreased by the such crucible shape. The film having good quality is thus formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an evaporation source for vacuum evaporation, in particular to a crucible for electron beam evaporation.

BACKGROUND OF THE INVENTION In recent years, electron beam evaporation has been rapidly growing along with advances in thin film element structures that accompany the increasing functionality and miniaturization of electronic components. The shape of the hearth crucible, which is the evaporation source, was a circular mortar shape, as shown in FIG.

The material to be evaporated is put into this circular mortar-shaped crucible and heated and evaporated with an electron beam. material, e.g. Ni/C
The need in the electronics industry to deposit alloys such as O, Nf/Fe, and Te/Se has particularly increased in recent years.

Problems to be Solved by the Invention Of course, continuous vapor deposition over a long period of time is a problem.In vacuum vapor deposition, the material to be vaporized must be heated and evaporated. , basically exists. Therefore, in materials with a large vapor pressure difference, such as N i /Cr, Cr tends to fly at first.
Generally, the composition of the deposited film changes such that the amount of Nl gradually increases.

Attempts have been made to keep the film composition constant by constantly replenishing decreasing materials or materials that fly easily.
In the conventional circular mortar-shaped crucible as described above, there is a problem in that bumping called splash occurs when the material is fed, and microparticles adhere to the film, resulting in a lumpy appearance.

The reason for this has not yet been fully analyzed, but the rapid temperature rise (1000 to 20oO℃ to replenish the solid material)
(temperature change) or charge-up due to contact with the electron beam.

Therefore, there have been proposals for a method of supplying preheated materials, but the equipment becomes complicated and the effect is not as expected.

In view of the above problems, the present invention provides a crucible for an electron beam evaporation hearth that is suitable for supplying evaporation materials to suppress changes in film composition in the evaporation of multi-component materials with large vapor pressure differences.

Means for Solving the Problems In order to solve the above-mentioned problems, in the present invention, the crucible shape of the hearth for electron beam evaporation is made into an oblong mortar shape.

Function The present invention has a crucible shaped like an oblong mortar.
The electron beam heating evaporation section and the material supply section can be separated, thereby reducing splash during material supply.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the crucible shape in an embodiment of the present invention, where 1 is a crucible, 2 is a hearth, 3 is an electron beam heating section,
4 is a material supply section.

Here, the cooling structure of the hearth is designed so that the material supply section is at a lower temperature than the electron beam heating section.

As shown in FIG. 2, the electron beam heating section is defined as a circular area drawn by a distance 5 connecting the beam sweep center 6 of the electron beam and the outermost edge of the beam sweep.

The material supply section is defined as a circular area drawn by the center 7 of the part where the official materials fall and the above 6.

We believe that the shape of the crucible can be designed by specifying the amount of overlap between the material supply section and the electron beam heating section.
As a result of repeated experiments, the radius of the electron beam sweep was 10
m/m or less, splashes occurred frequently even if there was an overlapping part. When the radius is 10 to 25 m/m, there may be an overlapping portion, but it has been found that it is desirable that the amount is less than or equal to Z of the radius. 25 more
It was found that when the ratio is m/m or more, the overlap amount is less than %.

Effects of the Invention As described above, the present invention makes the shape of the crucible of the hearth for electron beam evaporation into an oblong mortar shape, thereby making it possible to perform continuous evaporation over a long period of time or evaporation in multi-component alloy evaporation of components with different vapor pressures. It significantly reduces splash during material feeding and enables the formation of a high-quality film, which brings multiple effects to actual production.

Furthermore, since the shape is oval, the shape of the hearth liner is easier than that of a polygon, and the cooling effect is uniform to prevent cracking, resulting in a reduction in film-forming cost.

[Brief explanation of drawings]

FIG. 1a is a front view of one embodiment of the present invention, FIG. 1 is a side view of the same, FIG. 2 is a schematic front view defining an electron beam heating section and a material supply section, and FIG. FIG. 3 is a front view of the same, and FIG. 3 is a side view of the same. 1... Crucible, 2... Hearth. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2 Figure 3 α

Claims (1)

[Claims] A crucible for electron beam evaporation with a hearth part shaped like an oblong mortar.