JPH0414185B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is not based on electrochemical means such as plating technology, but rather on the production of thin films such as material thin film layers on various substrates (metals, semiconductors, insulators, etc.). The present invention relates to a device for ejecting vapor of a molten substance (such as lead, copper, gold, silver, gadmium, tellurium, etc.) in a thin film forming device such as a vacuum evaporation method.

In general, this type of thin film forming apparatus heats the molten material to be deposited in a closed crucible with a steam outlet, and heats it in a high vacuum atmosphere (e.g., gas of 10 ^-4 Torr or less). pressure)
By forming a pressure difference of at least 10 times or more between the molten material vapor and the molten material vapor formed in the crucible due to heating, and maintaining the thermal equilibrium state of the molten material vapor in the crucible, the molten material is released from the steam outlet. Steam is injected into a low gas pressure atmosphere, a supercooled state is formed near the steam outlet due to adiabatic expansion, and a lumpy atomic group (cluster) is created by condensation due to the supersaturated state, some of which is ionized. A negative high voltage applied to the ion extraction electrode as a cluster ion beam gives kinetic energy to the cluster ion beam, and forms a thin film layer of a predetermined material on the substrate together with the neutral cluster beam. .

[Conventional technology]

3A and 3B show a plan view and a vertical cross-sectional view showing the main parts of a molten material vapor ejecting device in a conventional thin film forming apparatus. 4A and 4B show the case where the crucible 1 has a rectangular box shape. 1 has a predetermined molten substance 5 inside
2 is a heating filament that surrounds the crucible 1 at a predetermined interval and heats the crucible 1; 3 is a heating filament that closes the upper opening of the crucible 1 and has a steam jet hole with a predetermined inner diameter in the center of the ceiling. The lid body 5a formed with 4 is formed within the crucible 1 and is a molten material vapor that is ejected from the steam ejection hole 4.

Since the conventional steam ejecting device is configured as described above, when the molten substance 5 in the crucible 1 heated by energizing the heating filament 2 evaporates, the steam 5a increases the pressure in the crucible 1. The molten material vapor 5a spreads laterally due to adiabatic expansion caused by the pressure difference, and is heated and cooled by the adiabatic expansion. A cluster of atoms (thruster) in which about 1000 atoms are loosely bonded is formed, and this cluster is used to form a thin film of a material to be deposited (not shown).

[Problem that the invention seeks to solve]

In the conventional steam ejecting device described above, there is a drawback that if the distance between the heating filament 2 and the outer circumferential wall of the crucible 1 is not constant, the crucible 1 will not be heated evenly. When the crucible 1 has a rectangular box shape, the heating temperature of the portion of the crucible that does not face the heating filament 2 is extremely low, and the molten substance 5 in the crucible is not melted.
The amount of ejection of the molten material vapor 5a becomes unstable,
There is a drawback that it deteriorates significantly.

This invention was made with attention to this point, and the invention uses steam to prevent the heating temperature of the crucible from becoming uneven due to "variations" in the distance between the heating filament and the outer peripheral wall of the crucible, or due to the shape of the crucible. The present invention aims to provide a jetting device.

[Means for solving problems]

The steam ejecting device according to the present invention has a thermostatic metal plate having a predetermined thickness and good thermal conductivity and heat retention property polymerized and fixed at a predetermined position on the outer circumferential wall of a crucible.

[Effect]

In this invention, a constant temperature metal plate with good thermal conductivity and heat retention is polymerized and fixed at a predetermined position on the outer peripheral wall of the crucible, so that the distance between the heating filament and the outer peripheral wall of the crucible is "Dispersion"
Also, the heating temperature of the crucible does not become uneven overall depending on the shape of the crucible.

[Embodiment of the Invention] Fig. 1 and Fig. 2 A and B each show an embodiment of the present invention. The plan view and FIG.
The same reference numerals as those in FIG.

First, in FIG. 1, reference numeral 8 denotes an ionizing electron emitting filament which is disposed concentrically at a predetermined interval above the crucible 1 containing the molten material 5, and which ionizes the clusters generated from the molten material vapor 5a. A grid 7 accelerates the electrons emitted from the grid 8; an accelerating electrode 9 disposed at a predetermined interval above the grid 8 controls the acceleration of the ionized cluster; and 10 a deposition target for depositing a thin film of material on the surface. 11 is a vacuum chamber containing each component; 6 is a constant temperature metal plate polymerized and fixed on the outer peripheral wall of the crucible 1 that does not face the heating filament 2; The plate 6 is made of tantalum, for example, which has good thermal conductivity and heat retention.
The constant-temperature metal plate 6 is provided to make the heating temperature of the crucible 1 uniform throughout and to keep the crucible 1 warm.

Since the molten substance vapor ejecting device of the present invention is configured as described above, thermionic electrons emitted from the heating filament 2 to heat the crucible 1 are applied between the crucible 1 and the heating filament 2. The applied positive bias voltage impinges on the crucible 1 and heats it. At this time, as shown in FIG. 2, the distance a between the heating filament 2 and the constant temperature metal plate 6 is the distance b between the heating filament 2 and the crucible 1.
Since it is shorter and has corners, the electric field concentrates and thermionic electrons concentrate, resulting in a much larger heat input than crucible 1. The thermostatic metal plate 6 heated to a high temperature by this heat input has good thermal conductivity and transfers heat to the surface of the crucible 1 that does not face the heating filament 2, and as a result, the crucible 1 heats the entire circumference. The temperature becomes uniform to the same extent as the molten material vapor 5
The ejection amount of a is stabilized, and the thermal efficiency of the crucible 1 is improved due to the heat retention properties of the constant temperature metal plate 6.

〔Effect of the invention〕

As mentioned above, in the molten substance vapor ejecting device of the present invention, a constant temperature metal plate that equalizes the temperature of the crucible is polymerized and fixed on the outer peripheral wall of the crucible that does not face the heating filament. The heat of the crucible, which is locally heated to a high temperature by the filament, is transferred to the outer peripheral wall of the crucible that does not face the heating filament, so the heating temperature of the crucible is uniformized over the whole, and the molten material is This not only stabilizes the amount of steam ejected, but also improves the thermal efficiency of the crucible due to the heat retention properties of this constant-temperature metal plate, which has the excellent effect of creating a thin film on the material to be deposited through a low-temperature process. It also has.

[Brief explanation of drawings]

Fig. 1 and Figs. 2A and 2B all show one embodiment of the present invention. Fig. 1 is a longitudinal cross-sectional view of the steam ejecting device, Fig. 2A is a plan view of the main part, and Fig. 2A is a plan view of the main part. B is a longitudinal sectional view thereof. FIGS. 3A and 3B and FIGS. 4A and 4B are a plan view and a vertical cross-sectional view, respectively, showing the main parts of a conventional molten material steam ejection device. In the figure, 1 is a crucible, 2 is a heating filament, 3 is a lid, 4 is a steam outlet, 5 is a molten substance,
5a is a molten substance vapor, and 6 is a constant temperature metal plate.
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. In a crucible that is heated by a heating filament and contains a molten substance therein, a thermostatic metal plate that equalizes the temperature of the crucible is provided on the outer peripheral wall of the crucible that does not face the heating filament. A device for ejecting steam from a molten substance, characterized in that it is polymerized and fixed. 2. The molten substance vapor ejecting device according to claim 1, wherein tantalum is used for the constant temperature metal plate. 3. The molten material vapor ejection device according to claim 1, wherein a vapor ejection hole for ejecting molten material vapor is formed in the center of the ceiling of the lid that closes the upper opening of the crucible. . 4. Claim 1, characterized in that a grid is provided concentrically above the crucible to accelerate electrons emitted from an ionizing electron emitting filament that ionizes clusters generated from molten metal vapor. A device for ejecting steam from a molten substance as described in 1.