JPS5943871A - Vessel for storing material to be evaporated - Google Patents

Abstract

PURPOSE:To provide a titled vessel which enables stable evaporation and eliminates uneven evaporation as well as uneven film thickness and characteristics of the film deposited by evaporation by providing an opening smaller than the evaporation area for heating and evaporating a material to be evaporated and decreasing a radiation rate. CONSTITUTION:A material 3 to be evaporated in a vapor deposition boart 4 of a vapor source 1 in a vacuum deposition device disposed therein with a substrate 2 to be deposited thereon with a film by evaporation oppositely to the source 1 is heated and evaprorated by heaters 5, 6 and the vapor is scattered through an opening 9 toward the substrate 2. The opening 9 is constituted smaller than the evaporation area of the material 3 and the boat 4 is constituted of wall parts 7, 8 having low radiation rates such as Al or the like having <=0.4, more preferably <= radiation rate and having specularly finished surfaces. The heat radiation from the parts 7, 8 is decreased and the material 3 is uniformly heated. It is also possible to decrease the radiation rate of the materials 7, 8 by covering or coating a material having <=0.4 radiation rate on said parts.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is used to heat and evaporate an evaporation material made of, for example, selenium and tellurium, and is configured such that the evaporation material is led out through an opening smaller than the evaporation area of the evaporation material. The present invention relates to an evaporation material container.

This type of evaporation material container (hereinafter referred to as a evaporation boat).

), a so-called open boat having an upper opening approximately the same size as the evaporation area of the evaporation material is known.

However, in such an open boat, it is difficult to control the deposition rate, and there are serious practical problems such as frequent bumping. Further, even if such an open boat were made of a material with a low emissivity, it would be impossible to use it due to the above-mentioned reasons.

On the other hand, as a boat that eliminates the drawbacks of open boats,
There is a so-called Knudsensel type. By constricting the upper opening to be narrower than the evaporation area, the evaporation rate is effectively controlled, and the evaporated matter that flies out due to bumping adheres to the wall before reaching the upper opening. It is very superior in that it does not fly to the deposition substrate side).

However, because the thermal radiation rate from the outer surface of the boat, especially the outer surface of the wall in contact with the evaporation material, is as high as 0.5 to 0.7,
It was found that the variation in temperature distribution is large in the length direction of the evaporation source, and the variation in temperature distribution is also large in the height direction of the evaporation source. Such variations in temperature distribution cause uneven evaporation, which leads to defects in the thickness and characteristics of the deposited film, and reduces the yield of the product.

The present invention has been made in order to take advantage of the features of the evaporation boat as described above while eliminating its drawbacks. ) This relates to an evaporative material container characterized by the following.

According to the present invention, since the emissivity of the container is reduced to 0.4 or less, the heat released to the outside is significantly reduced, and the temperature in the length direction and even depth direction of the evaporation source is particularly reduced. Variations in distribution are reduced, thereby making stable evaporation possible, eliminating uneven evaporation, and unevenness in the thickness and properties of the deposited film, and greatly improving yield.

In the present invention, the entire container is formed of a material with an emissivity of 0.4 or less, or at least the outer surface is coated with a cover material with an emissivity of 0.4 or less, or furthermore, the container is made of a material with an emissivity of 0.4 or less. It is desirable that the material is applied to at least the outer surface.

Constituent materials with low emissivity (small amount of radiant heat) include mirror-finished M, brass, Cr, α, Au, F.
e, Mo, Ni, Pt, Ta, W, etc. These may be finished into a container shape by molding or the like, or in the case of the above coating, may be applied by surface coating such as thermal spraying or vapor deposition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

FIG. 1 schematically shows the main parts of a vacuum evaporation apparatus, in which an evaporation source 1 is placed in a pelger (not shown), and a body 2 to be evaporated (for example, a rotatable aluminum drum) is placed facing the evaporation source 1. are arranged. The evaporation source 1 consists of a evaporation boat 4 containing an evaporation material 3 (for example a selenium-tellurium alloy). This boat 4 is composed of a clay wall section 7 that houses two heater lamps 5 and 6 arranged in upper and lower stages, and a lower wall section 8 that houses the evaporative material 3. Steam is allowed to fly outward (ie, toward the base 2) in a controlled manner from the upper opening 9, which is smaller than the evaporation area of the material 3. This is what is called a Knudsencell type evaporation source.

In this evaporation source, according to the invention, the boat wall 7
and 8 (in other words, the entire boat) has an emissivity (ε) of 0.4
Hereinafter, it is made of aluminum having a highly polished surface of 0.1 or less. Due to this low emissivity material, the overall heat release, especially from the wall portion in contact with the evaporative material 3, is significantly reduced.

FIG. 2 shows an example in which the boat wall main bodies 17 and 18 themselves are made of ordinary heat-treated stainless steel, but the outer surface of the boat is covered with a cover material 10 made of a low emissivity material as described above. There is. Even with this configuration, the amount of heat released by radiation from the outer surface of the boat is significantly reduced. FIG. 3 shows a boat provided with a cover material 10 similar to that in FIG. 2, but with a different shape of the container for the evaporative material 3.

In the example of FIG. 4, a low emissivity material as described above is applied by thermal spraying or vapor deposition to the outer surface of wall portions 17, 18 similar to those of FIG.

In the examples shown in FIGS. 2 to 4, variations in temperature distribution due to heat release from the boat are prevented by the cover material 10 or by adding a coating layer. Note that these low emissivity materials may extend to the inner surface of the boat.

By applying the low emissivity materials as described above, the side shape of each of the boats described above is shown in FIG.
A side view corresponding to the boat shown is shown. ), the difference between the maximum temperature and the minimum temperature (
ΔT) becomes extremely small, on the order of several degrees Celsius. Therefore, for example, if one temperature control system is used by placing a thermocouple at one temperature measurement point (for example, intermediate point B) for the length of boat 1, which is 3 m, it is possible to perform desired temperature control. Therefore, when the photoreceptor film is formed as a vapor deposited film, the sensitivity unevenness can be eliminated and the characteristics can be improved. On the contrary,
In conventional boats, the above-mentioned ΔT is as large as 20-odd degrees Celsius to 30-odd degrees Celsius, and problems such as uneven evaporation as described above are likely to occur.

Regarding the temperature distribution in the depth direction of the evaporation material, as shown in FIG. is Tc, and in the case of the conventional example in Figure 6A (emissivity of 0.5 or more and dog), TA (330°C) >> TB (3
00°C)>'rC (295°C), the variation in temperature distribution increases. However, when a low emissivity material is used as the wall material 8 according to the present invention (FIG. 613), TA (3
02℃) =:=TB (300℃) +Tc (
299°C), and the temperature is also uniform in the depth direction.

That is, in the conventional example, TA - TB is large, and as the evaporation progresses, the evaporation temperature increases from 330°C to 300°Ct.
Since 0°C also changes, uneven evaporation occurs, but in this example, rA
-TB dries up at about 2°C, allowing stable evaporation.

Figure 7 shows the Te9 degree profile of the Se-i,"e deposited film obtained by the method described above. During this deposition, a 5e-Te alloy with a Te content of 13.5% by weight was evaporated. This was used as a material and heated to 300° C., and the degree of vacuum in the Pelger was set to 10 Torr or less.

In the length direction of the evaporation source shown in FIG. 5, in the conventional apparatus, the vapor deposited film as shown by the solid line in FIG. A Te 9 degree distribution in the thickness direction was obtained, and it was found that the Te concentration in the deposited film was significantly non-uniform locally due to temperature variations. However, in accordance with the present invention, when the boat is formed, coated or coated (see FIGS. 1-4) with a material having an emissivity of 0.06, for example, the temperature rises as shown by the dashed line in FIG. It was found that the Te concentration in the deposited film was very uniform in terms of location because the distribution variation was very small, and the variation was suppressed to within ±1 inch.

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 evaporation boat can be changed, and the above-mentioned evaporation charge may be accommodated in a separate container and placed within the space of the evaporation source. Even in this case, the outer wall of the evaporation source can be made of a low emissivity material according to the invention. In addition, the evaporation material used is not limited to Se-Te, but Se
-S, Fe-Ni, AgBr-I, etc. may also be used.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram of the main parts of a vacuum evaporation apparatus, and FIGS. 2, 3, and 4 are sectional views of the evaporation source from each side. , FIG. 5 is a side view of the evaporation source, FIG. 6A is an enlarged sectional view of the evaporation material and a part of the boat according to the conventional example, FIG. 6B is an enlarged sectional view similar to FIG. 6A in this embodiment, and FIG. 1 is a diagram showing the Te concentration profile in the obtained deposited film. The symbols shown in the drawings are as follows: 1... Evaporation source 2... Evaporation target substrate 3... Evaporation material 4... φ Vapor deposition boat 5.6... Heater 7.8... -Low emissivity wall portion 9...Top opening 10...Low emissivity cover material addition...Low emissivity coating layer. Attorney Hiroshi Dokaki Saka No. 219 Condolences No. 310

Claims (1)

[Claims] 1. In an evaporation material container used when heating and evaporating an evaporation material and configured such that the evaporation material is led out through an opening smaller than the evaporation area, the emissivity An evaporative material storage container characterized in that: is 0.4 or less. 2. The evaporation material container according to claim 1, which is made of a material having an emissivity of 0.4 or less. 3. The evaporative material container according to claim 1, wherein at least the outer surface is coated with a cover material having an emissivity of 0.4 or less. 4. The evaporative material container according to claim 1, wherein at least the outer surface is coated with a material having an emissivity of 0.4 or less. 5. The first claim in which the emissivity is 0.1 or less
The evaporative material container described in any one of Items 1 to 4.