JPS6157391B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a vapor deposition method for forming a thin film, and in particular to forming a thin film having a desired thickness distribution using a vapor deposition material whose deposition rate depends on the temperature on a substrate. This relates to a vapor deposition method that allows for

Technical background of the invention and its problems Generally, when forming a thin film by vapor deposition, it is performed using an apparatus configuration as shown in Fig. 1 for the purpose of forming the film with a uniform thickness. There is.

As shown in the figure, for one evaporation source 1 that heats and evaporates a material to be evaporated (hereinafter referred to as evaporation material), there are multiple substrates 2 on which the evaporation material is attached and a thin film is formed. There are
Each of them is arranged in an axially symmetrical position so that the same positional relationship can be obtained with respect to the evaporation source 1. This is to ensure that all the thin films formed on each substrate 2 are homogeneous, and furthermore, each substrate 2 revolves around its axis (swivel motion), and each It is configured such that each arbitrary point on the substrate 2 rotates on its own axis so that each arbitrary point on the substrate 2 can obtain an equal positional relationship with respect to the evaporation source 1.

3 and 3' are heaters that heat the substrate 2, increasing the adhesion strength of the thin film to the substrate 2, or increasing the light emitting properties of the thin film when it is formed as an EL (electroluminescence) element. They are provided on both the front and back sides of the substrate 2 to heat it.

By the way, when forming a single-layer thin film, it is possible to form a thin film with a sufficiently uniform thickness using the above-mentioned apparatus configuration. When forming a multilayer film by stacking multiple layers, it has been difficult to obtain a sufficiently uniform film thickness because the layers are stacked even if there is a small error. Therefore, there is a need to develop a method for forming a single layer film with a desired thickness distribution in order to cancel out such non-uniform parts of the film thickness and form a multilayer film with an overall uniform thickness. .

Summary of the Invention The present invention has been devised in view of the above-mentioned circumstances of the prior art and to effectively solve the problems.

That is, in the present invention, a material such as zinc sulfide whose deposition rate depends on the temperature on the substrate is used as the evaporation material, and a heater provided on the evaporation source side of the substrate to heat the material is used with the substrate as a reference. On the opposite side, a reflective plate is provided to adjust the amount of heat transferred from the heater to the substrate, and by creating a desired temperature distribution on the substrate, a thin film having a desired thickness distribution is formed. The purpose of the present invention is to provide a vapor deposition method that enables the following.

Embodiments of the Invention A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

First, Figure 2 is a graph showing the deposition rate as a function of the substrate temperature in terms of film thickness when zinc sulfide, which is also known as a typical material for EL elements, is used as the deposition material.The higher the substrate temperature, the lower the deposition rate. It is shown. In other words, the higher the substrate temperature, the thinner the formed thin film becomes.

FIG. 3 shows the configuration of an apparatus used in the vapor deposition method according to the present invention, and corresponds to FIG. 1 showing an example of the prior art. Therefore, similar components will be given the same numbers and redundant explanations will be omitted.

As shown in the figure, the surface of the substrate 2 facing the heater 3' is covered with a reflecting plate 4 that partially reflects the heat radiated from the heater 3 to the substrate 2 and passing through it toward the substrate 2. It is set in.

This reflecting plate 4 may be formed to cover approximately the central portion of the substrate 2 as shown in FIG. 4, or may be formed to cover the peripheral portion of the substrate 2 as shown in FIG. 5, for example.

Furthermore, as shown in FIGS. 6 and 7, if the edge portion 5 of the reflector 4 is slightly bent toward the heater 3' side, the boundary between the part covered by the reflector 4 and the part not covered by the reflector 4 can be The slope of the temperature distribution can be changed continuously, and the thickness distribution of the obtained thin film can also be changed continuously as shown in FIGS. 8 and 9.

Therefore, when a multilayer film with non-uniform film thickness is formed by stacking many single-layer thin films formed by conventional techniques, a single-layer thin film with a film thickness distribution that offsets this non-uniformity is necessary. By forming this by the method of the present invention and superimposing it on the multilayer film described above, a multilayer film with a uniform thickness can be obtained.

In this example, the reflector was provided in contact with the substrate, but it goes without saying that even if the reflector is provided with a gap between them, the same action and effect as in this example can be achieved. be.

In FIG. 3, the heater 3 on the evaporation source 1 side was considered as the heater that performs the main heating function when forming the desired temperature distribution on the substrate 2, but for example, the heater 3' on the opposite side was considered. If it is regarded as the main heating source, it can be used as a shielding plate instead of the reflecting plate 4, and the temperature distribution on the substrate 2 can be adjusted to block the radiant heat from the heater 3'. In this case, the above-mentioned A temperature distribution opposite to the temperature distribution on the substrate 2 exemplified in the example can be obtained, and a thickness distribution of the formed thin film can also be obtained opposite to that of the above-mentioned example.

Effects of the Invention As is clear from the above explanation, the present invention provides the following excellent effects.

In other words, by using a deposition material such as zinc sulfide whose deposition rate depends on the temperature on the substrate, and adjusting the amount of heat transferred from the heater to the substrate on the opposite side of the substrate with respect to the heater that heats the substrate. Since a reflective plate is provided to generate a desired temperature distribution on the substrate, a thin film having a desired thickness distribution can be formed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a schematic configuration of an apparatus employed in a conventional vapor deposition method, and FIG. 2 is a graph showing the deposition rate of the vapor deposition material used in the vapor deposition method according to the present invention as a function of substrate temperature in terms of film thickness. FIG. 3 is an explanatory diagram showing a schematic configuration of an apparatus used in the vapor deposition method according to the present invention, and FIGS. 4 and 5 are plan views each showing an example of a reflection plate used in the vapor deposition method according to the present invention. , FIGS. 6 and 7 are side views of FIGS. 4 and 5, respectively, and FIGS. 8 and 9 are side views of thin films formed on the substrates shown in FIGS. 6 and 7, respectively. It is a graph diagram showing thickness distribution. In the figure, 1 is an evaporation source, 2 is a substrate, 3 and 3' are heaters, and 4 is a reflection plate.

Claims (1)

[Claims] 1. A heater for heating the substrate is provided on the evaporation source side of the substrate for an evaporation source of a deposition material whose deposition rate depends on the temperature on the substrate, and a heater is provided on the opposite side of the substrate with respect to the substrate. , a reflective plate is provided so as to adjust the distribution of the amount of heat transmitted from the heater to the substrate on the substrate to a desired distribution, and vapor deposition is performed;
A vapor deposition method characterized in that the thickness distribution of the thin film of the vapor deposition material formed on the substrate is made to depend on the temperature distribution on the substrate.