JPS59179148A - Evaporation source - Google Patents

Abstract

PURPOSE:To prevent effectively the evaporation of heater material or its oxide and to improve characteristics of vapor-deposited film by covering the heater or at least the neighbourhood of the part for covering the heater with a covering member. CONSTITUTION:An approximately cylindrical evaporation source 22 is disposed to below a substrate 21 to be vapor-deposited in a vapor-deposition vessel 20, and gaseous oxygen ionized or activated by a gas-filled discharge tube or unactivated gaseous oxygen is fed from an oxygen introducing pipe 23. An evacuation pipe 24 is connected to a vacuum pump to evacuate a vapor-deposition vessel 20 to a specified degree of vacuum. The evaporation source 22 consists of a container 22a for contg. a material to be evaporated 1 and a crucible formed to one body with a resistance heating type heater 3 wound around the crucible and an approximately cylindrical covering part 22b for the heater which surrounds the heater at a specified distance from the heater.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Industrial Application Field The present invention relates to an evaporation source used for vapor deposition of aluminum oxide, transparent conductive films, silicon oxide, etc.

2. Prior Art For example, when depositing aluminum oxide, there is a known technique in which an AA evaporator is evaporated onto a substrate to be deposited using a resistance heating method using a tungsten heater while supplying oxygen gas in a deposition tank.

However, especially since the vapor deposition is performed in oxygen gas, the heater is likely to be oxidized and a heater metal oxide having a high vapor pressure is likely to be generated, which evaporates simultaneously with the evaporator and mixes into the vapor deposited film. Therefore, the quality of the obtained aluminum oxide film deteriorates, such as a decrease in specific resistance, and the film becomes unstable.

When depositing a transparent conductive film using In-5n as the evaporator, the specific resistance of the conductive film increases due to the incorporation of the heater metal oxide described above, and in any case, the desired film characteristics cannot be achieved. I can't get it.

As a countermeasure for these problems, as shown in FIG. 1, there is a structure in which a heater 3 disposed around a crucible 2 containing an evaporative material 1 is coated with an alumina coat 4 and fixed to the crucible. However, in this case, the coating material 4 peels off or cracks due to the difference in thermal expansion coefficient with the heater metal 3, and the heater metal is oxidized and evaporated from these peeled or cracked parts, resulting in the above-mentioned A similar problem occurs. Furthermore, as shown in Fig. 2, there is a structure in which an alumina crucible 12 is attached to a cylindrical insulator 14 with a built-in heater 3 through its upper opening, but the bonding surfaces of the crucible 12 and insulator 14 are in complete contact with each other. As a result, heater metal leaks out and mixes into the deposited film.

As described above, in the conventional evaporation source structure, it is not possible to prevent the oxide of the heater metal from being mixed into the deposited film (or into the evaporation material in the crucible). This becomes particularly difficult when forming a deposited film on a wide substrate.

Moreover, what is important is that in conventional evaporation sources, both ends of the heater led out from the evaporation source are exposed. That is, both ends of these are easily affected by the heat of the evaporation source and are easily oxidized in oxygen, and for the same reason as mentioned above, the evaporation of the oxide deteriorates the quality of the deposited film. It is from.

3. OBJECT OF THE INVENTION An object of the present invention is to provide an evaporation source that can effectively prevent evaporation of a heater material or its oxide, thereby improving and stabilizing the performance of a deposited film.

Another object of the present invention is to provide an evaporation source suitable for wide or large area deposition.

4. Structure of the invention, that is, the evaporation source of the present invention has an evaporative material storage section that stores an evaporative material, and a heater covering section that surrounds a heater arranged around the evaporation material storage section, and The heater led out from the heater covering part is covered with a cover member at least in a region near the heater covering part.

5. Examples Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a cutaway view of the main parts of the vacuum evaporation apparatus. In the vapor deposition tank 20, a substantially cylindrical evaporation source 22 is arranged below the substrate 21 to be vapor deposited, and oxygen ionized or activated by a known gas discharge tube (not shown) is supplied from an oxygen introduction tube 23. Gas or inert oxygen gas is supplied. The exhaust pipe 24 is connected to a vacuum pump (not shown), and sucks the inside of the deposition tank 20 to a predetermined degree of vacuum.

As illustrated in FIG. 4, the evaporation source 22 has a substantially cylindrical shape that surrounds an evaporation material accommodating portion 22a for accommodating the evaporation material 1 and a resistance heating type heater 3 wound around the crucible portion at a predetermined distance. The shaped heater covering portion 22b is integrally molded (
In other words, it consists of a crucible (with no seams or gaps between them). Moreover, both ends of the heater 3 led out to the outside of the heater sheathing part 22b are passed through the pipe material 25 at least in areas adjacent to the heater sheathing part 22b (almost the entirety of both ends in the illustrated example). Covered by pipe material. The heater wire 3 led out from this pipe material 25 is
It is inserted between a pair of electrode plates 27 and 28 that are fixed through the bottom wall part 20a of the vapor deposition tank or provided on the first layer 26, and is mechanically fixed here and electrically connected to the board 26. Connected. As a result, the entire evaporation source 22 is spatially fixed within the vapor deposition tank while being supported by both leads 26. Note that an alternating current voltage (not shown) is applied between the pair of leads 26.

Although various materials can be selected for each component of the evaporation source 22, suitable materials are as follows. First, the evaporative material storage section 2
The crucible, which is an integrally molded body of the heater covering part 2a and the heater covering part 22b, is made of at least one kind (including mixtures) selected from the group consisting of quartz, poron nitride, aluminum oxide, zirconium oxide, and silicon carbide. It's good to be there. Among these, those made of boron nitride can be formed by cutting the block, and those made of other materials can be formed by sintering (aluminum oxide, 5iC) or melt forming (quartz). be.

In addition, a pipe material 25 that is a cover material for the lead-out end of the heater 3
As with the above crucible, quartz, boron nitride,
It is preferable that the material is made of at least one selected from the group consisting of aluminum oxide, zirconium oxide, and silicon carbide. Further, the heater wire 3 is one for resistance heating, and is preferably made of at least one kind selected from the group consisting of tungsten, molybdenum, tantalum, and platinum.

The evaporation material 1 accommodated in the crucible may be aluminum in the case of aluminum oxide vapor deposition, In, 5nIn-3n alloy or oxides thereof, SiO or in the case of transparent conductive film vapor deposition. In the case of evaporation of S i 02, SiO can be used respectively.

The evaporation source 22 configured as described above exhibits the following remarkable advantages over conventional evaporation sources.

(1) Since the heater wire 3 is placed in the internal space of the crucible, which is made up of an integral structure of the evaporator housing section 22a and the heater covering section 22b, the degree to which the heater metal is oxidized by oxygen gas is significantly reduced. . Moreover, since this crucible is made of an integral molded body and is separate from the heater 3, peeling and cracking that could not be avoided in the conventional example described above do not occur, and the vapor of the heater metal oxide leaks. There is no gap. Therefore, it is possible to effectively prevent the heater metal oxide from being evaporated and mixed into the deposited film (or evaporation material), and it is possible to improve and stabilize the film performance.

(2) In addition, since the heater lead-out end from the crucible is covered with the i-air cover material 25, oxidation of the heater lead-out end, which is easily oxidized by the heat of the crucible, is prevented, and the heater metal oxide is removed from there. It is possible to further prevent the deterioration of film quality due to mixing into the deposited film.

(3) Since the heater 3 is surrounded, it is difficult for the heat of the heater to dissipate to the outside, which makes it possible to uniformly heat the evaporator and to reduce energy loss due to heat radiation.

(4) The structure of the crucible has the function of accommodating the evaporator at the same time as covering the heater 3.
Assembly work becomes easier and the structure is simplified.

FIG. 5 shows a modification of FIG. 4, in which the pipe material 25 shown in FIG. 4 is replaced with a plate-shaped cover material 35 that covers the heater lead-out end of the crucible. This cover material 35 may also cover the sides of the heater lead-out end. Furthermore, as in the illustrated example, when the cover material 35 is attached from the lower end of the crucible to the above-mentioned glue layer 26, it is also possible to support the entire evaporation source in the vapor deposition tank with the cover material 35 itself. It is.

° Also, in FIG. 5, especially the bottom wall 20a of the vapor deposition tank.
If the bottom wall 20a is made of a material with a large heat capacity, or instead of this (or used in combination), cooling water is passed through the bottom wall 20a, and the bottom wall 20a is cooled by a water cooling pipe 3o. Even if the steam flows downward and tries to leak out of the evaporation source, it will condense there because the bottom wall 20a is kept at a low temperature, or even if oxides adhere to the bottom wall 20a, it will re-evaporate. can be prevented. by this,
Figures 6 to 8 show examples of evaporation sources suitable for vapor deposition on wide or large-area substrates, which can more effectively prevent impurities from entering the deposited film. .

That is, the entire evaporation source is formed into a rectangular parallelepiped shape corresponding to the shape of the substrate to be evaporated, and has a longitudinal evaporation material storage gTIt4.
The crucible 42 is an integrally formed body of the heater plate 2a and the covering portion 42b of the heater plate 43. The material of each component may be the same as the above example, but the heater 4
3 penetrates inside the covering part 42b in its length direction and is disposed vertically or horizontally, respectively, and its lead-out end is covered with a U-shaped cover material 45 to prevent metal oxide from scattering from the heater lead-out end. The structure is such that this is prevented. The heater 43 is made of, for example, a tungsten plate with a thickness of O,] ~ 0.5 mm, and the crucible 42 has a thickness of 0.5 to 5 mm, at least in the evaporator storage section 42a, considering mechanical strength and thermal responsiveness to the heater current. (preferably about 1 mm) thick.

FIGS. 9 to 11 show still other examples.

In this example, the evaporation source 52 is formed in a longitudinal shape, as in the examples shown in FIGS. 6 to 8, and is suitable for wide-width evaporation. However, the integrally molded body of the evaporative material storage portion 52a and the heater covering portion 52b has a substantially prismatic shape, and the heater wire 53 is passed through the insertion hole 50 formed therethrough.

The lead-out ends of the heater wires 53 are each covered with a pipe-shaped cover material 55 similar to the embodiment described above.

Next, using the evaporation source according to the embodiment described above, for example, the evaporation source shown in FIGS. 6 to 8, A7!
20. and I To (Indium Tin 0x
ide) were respectively deposited.

Swordfish eC) *A tungsten heater is used to heat the evaporative material.

**Oxygen was ionized with a high-frequency discharger and introduced into the deposition tank.

* * * A: 300 people per 11205 vapor deposited film thickness for one crucible. During the ITO deposition, two crucibles were arranged in series, and the total thickness of the deposited film was 250 people. Note that each crucible had a length of 30 cm and a width of 5 cm.

The film characteristics of each vapor-deposited film obtained under the above conditions are as follows when compared with those obtained in a conventional example (for example, the example in FIG. 2), using the evaporation source based on the present invention. This prevents the heater metal oxide from being mixed into the deposited film, making it possible to obtain a high-resistance AA20 film and a low-resistance ITO film with good reproducibility.

Although the present invention has been illustrated above, the above-mentioned example can be further modified based on the technical idea of the present invention.

For example, the shape and structure of the above-mentioned evaporation source may be changed in various ways, such as a square shape or an ellipse shape.

Further, at the heater lead-out end, only the region near the crucible that is easily affected by the heat of the crucible needs to be covered with the cover material. Also, during vapor deposition, multiple crucibles as described above may be arranged,
Alternatively, the transparent conductive film can be deposited not only by single-component deposition using an InSn alloy, but also by binary deposition in which In and Sn are placed in separate crucibles. Also, oxides of the above materials can be deposited. Various evaporation materials can be selected.

6. Effects of the Invention In the present invention, as described above, the evaporator storage part and the heater covering part are integrally molded, and furthermore, at least the area near the heater covering part at the lead-out end of the heater is covered with a cover material. It is possible to effectively prevent the vapor of the heater material or its oxide from leaking out and mixing into the deposited film, making it possible to improve and stabilize the film properties.

[Brief explanation of drawings]

Figures 1 and 2 show conventional examples, and Figure 1 (a) is a perspective view of the evaporation source (however, the crucible is shown with imaginary lines).
, FIG. 1(b) is a longitudinal sectional view of the same evaporation source, and FIG. 2 is a longitudinal sectional view of another evaporation source. 3 to 11 show embodiments of the present invention, in which FIG. 3 is a perspective view of the vapor deposition apparatus cut away, FIG. 4 is a vertical cross-sectional view of the evaporation source, and FIG. Fig. 6 is an exploded perspective view of another evaporation source; Fig. 7 is a front view of the same evaporation source; Fig. 8 is along the line ■-■ in Fig. 7. 9 is a perspective view of the crucible of another evaporation source, FIG. 10 is a longitudinal sectional view of the same evaporation source, and FIG. 11 is a longitudinal sectional view taken along the line XI-XI in FIG. 10. . In addition, in the reference numerals shown in the drawings, 1------evaporation material 3.43.53---heater wire or heater plate 21-11---evaporation target substrate 22.42.52-- ---- One evaporation source 22a, 42a, 52 a---Evaporation material storage section 2
2b, 42b, 52 t) -1---Heater covering part 23
-----1--Oxygen introduction pipe 25.35.45.55--1--Covering material 26--
---Leads 27, 28, ----Electrode plate. Agent: Patent attorney Hiroshi Aisaka (and 1 other person) Figure 1 → Figure 2 2 Figure 3 0

Claims (1)

[Claims] 1. An evaporative material accommodating portion that accommodates an evaporative material and a heater covering portion surrounding a heater arranged around the evaporative material accommodating portion are integrally molded, and the evaporative material accommodating portion that contains the evaporative material is led out from the heater covering portion. The evaporation source is characterized in that the heater is covered with a cover member at least in a region near the heater covering portion. 2. The evaporation source according to claim 1, wherein the crucible made of an integrally molded body of the evaporator storage part and the heater covering part has a circular, rectangular, or elliptical planar shape. 3. The evaporation source according to claim 2, wherein the planar shape of the evaporator storage portion is circular, rectangular, or oval. 4. Any one of claims 1 to 3, wherein the cover member of the heater is formed into a pipe shape or a plate shape.
Evaporation sources listed in section. 5. The evaporation source according to any one of claims 1 to 4, wherein the heater is formed in a linear or plate shape. 6. The crucible, which is an integrally molded body of the evaporator storage part and the heater covering part, is made of at least one member selected from the group consisting of quartz, boron nylide, aluminum oxide, zirconium oxide, and silicon carbide. An evaporation source according to any one of claims 1 to 5. 7. Claims 1 to 6, wherein the cover member of the heater is made of at least one member selected from the group consisting of quartz, poron nitride, aluminum oxide, zirconium oxide, and silicon carbide. Which of the following items is an evaporation source described in item 1? 8. The evaporation source according to any one of claims 1 to 7, wherein the heater is made of at least one member selected from the group consisting of tungsten, molybdenum, tantalum, and platinum. .