JPH0359984B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thin film forming apparatus for depositing a thin film onto a substrate, and particularly to improving the evaporation efficiency of a deposition substance.

[Conventional technology]

FIG. 4 is a perspective view showing a conventional heating device used in vacuum evaporation, which heats and evaporates a solid substance at room temperature and deposits it on a material to be deposited to form a thin film. 2 is a filament that surrounds the crucible 1; 3 is a filament heating power source that heats the filament 2; and 4 is a DC power source that is applied between the crucible 1 and the filament 2.

In the heating device configured as described above, the filament 2 is heated by the filament heating power source 3. At this time, the crucible 1 is heated by the radiant heat of the filament 2, and is further heated by the DC power source 4.
When a voltage is applied, electrons are emitted from the filament 2, and these electrons collide with the crucible 1,
Crucible 1 can be further heated.

[Problem that the invention seeks to solve]

In the conventional thin film forming apparatus as described above,
Since the filament 2 is arranged to surround the crucible 1, as the diameter of the crucible 1 increases, the temperature difference between the outer wall and the center of the crucible 1 increases. On the other hand, in order to continue stable and efficient evaporation, it is necessary that the temperature difference inside the crucible 1 does not become large. For this reason, the circular crucible 1 had a problem in that the evaporation efficiency was impaired when a large crucible 1 was used.

This invention was made to solve the above-mentioned problems, and the object is to obtain a thin film forming apparatus that can heat each part to a uniform temperature even when using a large-capacity crucible. It is something.

[Means for solving problems]

The thin film forming apparatus according to the present invention uses a rectangular parallelepiped-shaped crucible, bends the filament, and arranges the crucible to face each other with the crucible in between, and reduces the radius of curvature of the bending of the filament.

[Effect]

The thin film forming apparatus of the present invention can uniformly heat even a large crucible by using the filament facing the crucible, and furthermore, by reducing the bending radius of the filament, thermal deformation of the filament can be suppressed.

〔Example〕

FIG. 1 is a perspective view showing an embodiment of the present invention, in which 1 is a crucible with a rectangular cross section;
Both a and 2b are filaments placed opposite the crucible 1. Each filament is bent to form three stages, but of course there may be any number of stages greater than two.

In this way, the planar filaments 2a and 2b are
Since it faces the rectangular crucible 1, the crucible 1 can be heated uniformly. Furthermore, crucible 1
The advantage is that even if the width is constant, the length can be set as desired. That is, in order not to increase the temperature distribution, the internal volume of the crucible can be increased while keeping the crucible width below a certain value.

In addition, in the above embodiment, each filament 2
Although filaments a and 2b are shown as being composed of one piece and having no support other than at both ends, filaments 2a and 2b are heated to a high temperature, their elastic modulus decreases, and the filaments 2a and 2b are fixed at both ends. , 2b, the filaments 2a, 2b are largely deformed in a direction perpendicular to the longitudinal direction. Therefore, when the filament length becomes long, it may become difficult to uniformly heat the crucible 1 due to this deformation.

Therefore, as shown in Fig. 2, the filament 2
A support means 5 is provided to support filaments 2a and 2b at intermediate points, and by restraining deformation of filaments 2a and 2b, crucible 1 is heated uniformly. The position and number of the support means 5 can be changed as necessary.

FIG. 3 shows another embodiment. In each of the above embodiments, since the radius of curvature of the filament bending portion is large, deformation may not be sufficiently restrained in some cases.

In the embodiment shown in FIG. 3, in order to reduce the deformation, adjacent straight portions of filaments 2a and 2b are configured not to be parallel but to intersect with each other.
Furthermore, the radius of curvature of this bent portion is made as small as possible. According to experiments, in the case of a filament with a wire diameter of 0.7 mm, when the radius of curvature was 5 mm, the deformation was large, but when the radius of curvature was set to 2 mm,
There was almost no deformation, and there was a great effect on uniform heating of the crucible 1.

This structure can be applied both without the support means as in the embodiment shown in FIG. 1 and with the support means 5 shown in FIG. 2, depending on the wire diameter and length of the filament. Each has its own effect.

〔Effect of the invention〕

As explained above, this invention is constructed by bending the filament of the heating device into a flat shape and sandwiching the crucible, so that a large crucible can be heated to a uniform temperature, and the filament can be provided with an appropriate support. Alternatively, the filaments are arranged so as to intersect and the radius of the bending portion is made small to suppress deformation of the filament, which has the effect of preventing damage to the initial heating characteristics.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the invention, Fig. 2 is a perspective view showing an embodiment of the invention;
3 are perspective views showing other embodiments of the present invention, and FIG. 4 is a perspective view showing a conventional device. 1... Crucible, 2, 2a, 2b... Filament,
3...Filament heating power supply, 4...DC power supply, 5...
Support means. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A crucible, a filament, and a substrate to which a thin film is to be deposited are placed in a high vacuum region, and the filament heats the crucible to vaporize the vaporized material in the crucible and inject it into the high vacuum. The above-mentioned thin film forming apparatus for depositing a thin film on a substrate is provided with a rectangular parallelepiped-shaped crucible and a heating section in which the crucible is sandwiched between filaments formed by bending the crucible in a plane parallel to the longitudinal direction of the crucible. Characteristic thin film forming equipment. 2. The thin film forming apparatus according to claim 1, wherein a support means is provided at an intermediate position of the filament. 3. The thin film forming apparatus according to claim 1 or 2, wherein the bent portion of the filament is formed with a small radius of curvature.