JPS6338570A - Evaporating device for vacuum deposition - Google Patents

Abstract

PURPOSE:To shorten the time for forming a vapor deposited film and to prevent the generation of splashes by boiling and bumping by dividing the inside of a boat as an evaporating source by a partition plate having an aperture along the bottom plate surface thereof to a molten sample storing part and a molten sample evaporating part. CONSTITUTION:The central recess of a flat plate 1 is partitioned by the partition plate 4 to the molten sample storing part 2a and the molten sample evaporating part 2b. The bottom plate 5 is formed thin in the storing part 2a and thick in the evaporating part 2b and is so inclined as shown in the figure that the molten sample flows thereon. The partition plate 4 has the construction to allow the molten sample in the storing part 2a to flow along the bottom plate 5; for example, said plate is a mesh plate, etc. A material to be evaporated is filled into the storing part 2a and a voltage is impressed between flat plates 3 and 3', then the bottom plate 5 is so heated as to have the temp. gradient from the thick part to the thin part thereof. The temp. enough to allow the molten sample to complete the evaporation before arriving at the lowermost part of the evaporating part is attained in the evaporating part 2b when the bottom plate part of the storing part 2a is heated to the temp. enough to melt the sample. Since the molten sample is in the form of a liquid film, the sample is extremely liable to evaporate.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an evaporator for vacuum deposition.

[Conventional technology]

Conventionally, vacuum evaporation methods have been used to form electrodes of semiconductor ICs, hybrid ICs, etc., and to fabricate photoreceptors used in copying machines, printers, and the like. Vacuum deposition methods include an electron beam type, a resistance heating method using a boat, a coil, a crucible, etc., and a sputtering deposition method.

Among these methods, the resistance heating method is widely used because the heating mechanism is simple. In particular, the resistance heating method is effective for forming a vapor deposited film on a wide area substrate such as a thin film thermal head or an electrophotographic photoreceptor.
- Incidentally, films for thermal heads and electrophotographic photoreceptors are required to form a uniform, high-quality consistency free of droplets from evaporation sources over a wide substrate area.

In the case of a thermal head, if this droplet is present from the evaporation source during pattern formation by photoetching, it can cause a short circuit or disconnection, and in the case of an electrophotographic photoreceptor, this droplet can interfere with uniform charging during the charging process. This results in image unevenness during development and transfer, and poor cleaning during cleaning.

FIGS. 3(a) and 3(b) show the plane and side views of a boat as an evaporation source for vacuum evaporation, which has been commonly used in the past. The boat has a melting reservoir 2 in the center of a flat plate 1 made of Mo, Ta, stainless steel (SO3), etc.
It is constructed so that the vapor deposited material does not flow out of the boat when it is melted, and evaporation is carried out by applying electricity to 3.3' at both ends and heating it. However, in conventional boats like this, samples (Cr, Pd, etc.)

Boiling of Au, Ni, Cr, AL, Se, Te, etc.)
The drawback was that splashes were generated due to bumping.

This boiling and bumping is a phenomenon caused by poor convection of the molten sample and the molten sample existing near the boat surface becoming overheated.

Conventionally, methods for preventing splashes include improving the wettability of the boat surface (Japanese Patent Publication No. 57-22990) and roughening the boat surface (Japanese Patent Publication Nos. 56-156868 and 57-137).
468) or polishing (Japanese Patent Laid-Open No. 57-194253) to prevent boiling and bumping phenomena, and devising the shape of the boat (Japanese Patent Laid-Open No. 57-12).
3973, No. 57-192957), attempts have been made to prevent droplets from reaching the substrate from the boat, but due to continuous use of the boat, changes in the boat surface and imperfections in the boat shape, etc. Therefore, it was not always possible to sufficiently avoid droplets.

In other words, when attempting to form a deposited film in a relatively short time using a conventional boat, overheating of the molten sample near the boat surface cannot be avoided, and therefore boiling and bumping cannot be completely suppressed. Avoiding droplets is extremely difficult.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to provide an evaporator for vacuum evaporation that forms a deposited film in a relatively short time and does not cause splashing due to boiling or bumping.

That is, an object of the present invention is to provide an evaporation source for vacuum evaporation for forming a deposited film with a smooth film surface and high quality.

[Means for solving problems]

In order to avoid the boiling or bumping phenomenon of the sample caused by poor convection of the molten sample, which is a drawback of conventional resistance heating type evaporation equipment for vacuum deposition, the present invention is designed to reduce the temperature of the sample after turning it into a liquid film. , which is made to evaporate immediately.

Specifically, the present invention provides a boat for storing and melting an evaporated substance, and an evaporation apparatus for vacuum evaporation comprising a means for heating the evaporated substance in the boat, and a partition having an opening along the bottom plate surface of the boat. This is an evaporation device for vacuum evaporation in which the inside of the boat is divided by a plate into a sample melting reservoir and a melted sample evaporation section.

Description will be given below based on the attached drawings.

1(a), Cb) and <c> are a side view, a front view, and a plan view, respectively, of an example of the evaporation apparatus for vacuum deposition of the present invention.

This device is a modified Kozo boat in which a central concave portion of a flat plate 1 is partitioned by a partition plate 4 into a sample melt reservoir 2a and a melting material 2b.

The bottom plate 5 of the boat is thinner in the sample melting reservoir, thicker in the melting sample evaporation region, and sloped so that the molten sample flows into the sample reservoir.

The partition plate 4 may be of any construction so that the molten sample in the sample melt reservoir flows along the bottom plate surface, for example, a mesh plate (Fig. 1 (a)) or a partition plate with a gap between it and the bottom plate. These include a threshold plate (Fig. 2) that has been maintained in the same condition.

In this device, when a substance to be evaporated is loaded into the sample melting reservoir 21 and a voltage is applied between the flat plate ends 3 and 3', a temperature gradient is created from the thicker part to the thinner part of the molten sample evaporation part 2b. It is heated to hold. When the bottom plate of the sample melting reservoir 2a reaches a temperature sufficient to melt the sample, the melting sample evaporator 2b reaches a temperature sufficient to complete evaporation before the melting material reaches the bottom of the evaporator 2b. It has become.

Since the bottom plate of the sample melt reservoir section 21 is slanted, the sample melted near the bottom plate passes through the lower part of the mesh plate or plate-like member and flows in a liquid film state to the molten sample evaporation section 2b. Since the molten sample is in the form of a liquid film, it is extremely easy to evaporate, and since the liquid film does not easily become overheated, evaporation is carried out quietly in the peritoneal state without boiling or bumping.

〔Effect of the invention〕

As described above, by using the evaporation source according to the present invention, the molten sample can be heated without boiling or bumping.
Vacuum deposition can be performed.

Furthermore, even when a compound is used as a vapor deposition sample, there is an advantage that fractional distillation, which occurs in conventional boats that are designed to prevent boiling or bumping, is less likely to occur.

〔Example〕

Hereinafter, the evaporator for vacuum deposition of the present invention will be explained with reference to Examples and Comparative Examples.

Comparative Example A conventionally used boat with the structure shown in Figure 3 (stainless steel 0.5 cod, central section size 50 m wide x 120 m long)
5 seconds and 70 tons of evaporation material were loaded using a tube (10 m deep), the temperature was raised to 320° C. in 6 minutes, and then the temperature was maintained for 15 minutes to complete the vapor deposition. The distance between the evaporation source and the substrate is 3
0 cm, the degree of vacuum was 1X10-'Torr, and the substrate temperature was 70°C. At this time, the number of protrusions on the deposition surface caused by droplets adhering to the substrate was 0.5/d in total.

EXAMPLE In the vapor deposition apparatus of the present invention shown in FIG. 1, the recess size was 70 m in width x 150 m in length x 20 m in maximum depth, and the mesh was 3 m in diameter, and a thermocouple was attached to the bottom plate of the molten reservoir.

Se 70 f was charged into the melt reservoir, heated to 250° C. in 6 minutes, and then held at that temperature for 20 minutes to complete the vapor deposition. The other conditions were the same as in the comparative example. At this time, the number of protrusions on the deposition surface due to droplets adhering to the substrate was 0.
．． It was 01/-.

[Brief explanation of the drawing]

1(b) and (C) are a side view, a front view, and a plan view, respectively, of an example of an evaporator for vacuum deposition according to the present invention, and FIG. 2 is a side sectional view of another embodiment. and the third
Figures (@) and (b) are a plan view and a side view of a conventional resistance heating type vacuum deposition evaporator. Symbols in the figure: 1... Flat plate; 2... Molten reservoir; 2... Sample melt reservoir section: 2b... Molten sample evaporation section: 3, 3'... Voltage application section: 4...・Partition plate; 5...bottom plate.

Claims (1)

[Claims] In an evaporation apparatus for vacuum evaporation, which is equipped with a boat for storing and melting evaporated material, and a means for heating the evaporated material in the boat, a partition plate having an opening along the bottom plate surface of the boat is used to melt the sample inside the boat. An evaporator for vacuum evaporation characterized by being divided into a reservoir section and a molten sample evaporation section.