JP2020190012A - Vapor deposition source for vacuum evaporation apparatus - Google Patents

Abstract

To provide a vapor deposition source for a vacuum evaporation apparatus capable of increasing an evaporation amount per hour to provide a high vapor deposition rate to an object to be vapor deposited when a vapor deposition material is evaporated to vapor deposit on the object to be vapor deposited.SOLUTION: A vapor deposition source DS of a vacuum evaporation apparatus Dm according to the invention is arranged in a vacuum chamber 1 and evaporates a solid vapor deposition source Ms to vapor deposit to an object to be vapor deposited Sw. The vapor deposition source is constituted by an external vessel 4 having an ejection port 41 for ejecting a vapor deposition material evaporated toward the object to be vapor deposited, an internal vessel 5 which is interpolated to the external vessel from a wall surface thereof at an interval and accommodates the solid vapor deposition material, and heating means Ht allowing heating of the vapor deposition material in the internal vessel, the internal vessel being composed of a porous material.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vapor deposition source for a vacuum vapor deposition apparatus that is placed in a vacuum chamber to evaporate a solid vapor deposition material and deposit it on an object to be deposited.

For example, in the manufacturing process of an organic EL element, a solid thin-film deposition material (organic material) such as α-NPD is evaporated from a substrate or other material to be vapor-deposited in a vacuum atmosphere to form a predetermined thin film on the surface of the material to be deposited. There is a step of vapor deposition, and a vacuum vapor deposition apparatus is widely used in this vapor deposition step. A vapor deposition source used in such a vacuum vapor deposition apparatus is known, for example, in Patent Document 1. This includes a crucible with an open upper surface in the vertical direction and a heating means such as an induction coil for heating the crucible (see the column of prior art).

When, for example, a powdery vapor-deposited substance is filled in the crucible with the above-mentioned conventional vapor deposition source and the crucible is heated by a heating means in a vacuum atmosphere, the vapor-deposited substance in the crucible melts and then vaporizes, but the crucible The vaporized material vaporizes only from the liquid surface facing the top opening. As a result, there is a problem that the amount of evaporation per unit time under the same pressure is small and the vapor deposition rate for the material to be deposited is low (that is, the productivity is low). In this case, it is conceivable to raise the heating temperature of the pit, but depending on the vapor deposition material (organic material) used, if the heating temperature is raised, the vapor deposition material will be decomposed at the vapor deposition source, and the performance of the element will be improved. A thin film with the desired film quality cannot be deposited. For this reason, the development of a vapor deposition source for a vacuum vapor deposition apparatus capable of obtaining a high vapor deposition rate at a relatively low temperature has been required in recent years.

Japanese Unexamined Patent Publication No. 2010-1529

In view of the above points, the present invention is for a vacuum vapor deposition apparatus which can increase the amount of evaporation per unit time and have a high vapor deposition rate for the vapor-deposited material when the vapor-deposited material is evaporated and the vapor-deposited material is vapor-deposited. The subject is to provide a vapor deposition source.

In order to solve the above problems, the vapor deposition source for the vacuum vapor deposition apparatus of the present invention, which is arranged in a vacuum chamber and for evaporating a solid vapor-deposited substance to vapor-deposit on the vapor-deposited material, is directed to the thin-film deposition material. An outer container having an outlet for ejecting the evaporated vapor-deposited material, an inner container that is inserted into the outer container at intervals from the wall surface to contain the solid-film vapor-deposited material, and heating of the thin-film deposition material in the inner container. It is characterized in that the inner container is made of a porous body, which is provided with a heating means capable of the above.

According to the present invention, when the inner container of the vapor deposition source is filled with, for example, a powdered vapor-deposited substance and the outer container is heated by a heating means in a vacuum atmosphere, the inner container is heated by the radiant heat from the outer container. The heat transfer from the heated inner container melts the vapor-deposited substance in the inner container. At this time, since the inner container is composed of a porous body, the molten vapor-filmed substance impregnates the pores of the inner container, and the impregnated material is vaporized by the radiant heat from the outer container, and the vaporized vapor-filmed substance is vaporized. , The conduction of the space between the inner wall surface of the outer container and the outer wall surface of the inner container leads to the spout of the outer container through the space, and is scattered from this spout toward the vapor-deposited material. Become.

As described above, in the present invention, the amount of vaporized material evaporated by adding the vaporized substance from the liquid surface of the inner container facing the spout of the outer container to the vaporized substance from the wall surface of the inner container (vacancy on the wall surface, etc.). Can be dramatically increased as compared with the above-mentioned conventional example, and the vapor deposition rate with respect to the material to be vapor-deposited can be increased. As a result, the vapor deposition source for the vacuum vapor deposition apparatus of the present invention can obtain a high vapor deposition rate even at a low heating temperature. The gap between the inner container and the outer container is set in the range of 1 mm to 30 mm so that the air-impregnated pores can be efficiently vaporized while being efficiently heated by radiation from the outer container. ..

In the present invention, when the outer container is composed of a crucible having an open upper surface in the vertical direction, the inner container has a bottomed tubular contour with an open upper surface, and leg pieces are attached to the outer lower wall thereof. It is preferable to be provided. According to this, the inner container can be easily set in the crucible simply by inserting the inner container into the crucible with one leg side down and bringing the leg piece into contact with the inner bottom wall of the crucible. In addition to the space between the inner wall of the crucible and the outer wall of the inner container (first space), the vaporized vaporized material also passes between the inner bottom wall of the crucible and the outer bottom wall of the inner container. By forming a certain gap that defines the space (second space) (in other words, the vaporized vaporized material can be released from the holes in the outer bottom wall of the inner container), even more. The amount of evaporation can be increased, which is advantageous. In this case, if a plurality of spacer members are provided on at least one of the inner side wall of the crucible or the outer wall of the inner container, a certain gap defining the first space is formed only by installing the inner container. It is advantageous because the inner containers can be positioned concentrically in the crucible.

In the present invention, if the inner container is made of a carbon-based material having a predetermined porosity, for example, graphite, when the vapor-deposited substance in the inner container is melted, the melted vapor-deposited substance is impregnated into the pores of the inner container. It is possible to realize a configuration in which the material is vaporized by radiant heat from the outer container. The porosity of the inner container is appropriately set according to, for example, the viscosity of the vapor-deposited substance to be used when it is melted. When the melted vaporized substance impregnates the pores of the inner container, even if a part of it seeps out and falls on the inner bottom wall of the outer container, the exuded substance stays on the outer wall of the inner container or the outside. Anything that falls on the inner bottom wall of the container is quickly vaporized by radiation or heat transfer from the outer container, so no particular problem occurs.

(A) is a cross-sectional view schematically showing a vacuum vapor deposition apparatus including the vapor deposition source according to the embodiment of the present invention. (B) is a cross-sectional view for explaining the vapor deposition source by disassembling it. A partially enlarged sectional view showing a state of scattering of a vapor-deposited substance from a vapor-deposited source of the present invention.

Hereinafter, referring to the drawings, a glass substrate having a predetermined thickness having a rectangular outline (hereinafter referred to as “substrate Sw”), and a solid organic substance in which the vapor-deposited substance is evaporated (vaporized via a liquid phase) by heating. An embodiment of a vapor deposition source for a vacuum vapor deposition apparatus of the present invention will be described by taking as an example a case where a predetermined thin film is vapor-deposited on one surface of the substrate Sw as the material Ms. In the following, the terms indicating the directions such as "up" and "down" are based on FIG. 1, which indicates the installation posture of the vacuum vapor deposition apparatus.

With reference to FIGS. 1 and 2, Dm is a vacuum vapor deposition apparatus including the vapor deposition source DS of the present embodiment. The vacuum vapor deposition apparatus Dm includes a vacuum chamber 1, and a vacuum pump is connected to the vacuum chamber 1 via an exhaust pipe, and the vacuum chamber 1 is evacuated to a predetermined pressure (vacuum degree) to create a vacuum atmosphere. Can be formed. Further, a substrate transfer device 2 is provided above the vacuum chamber 1. The substrate transfer device 2 has a carrier 21 that holds the substrate Sw with the lower surface as a vapor deposition surface open, and a drive device (not shown) moves the carrier 21 and thus the substrate Sw in one direction in the vacuum chamber 1 at a predetermined speed. It is designed to be transported by. Since a known substrate transfer device 2 can be used, further description thereof will be omitted.

A plate-shaped mask plate 3 is provided between the substrate Sw transported by the substrate transport device 2 and the vapor deposition source DS. In the present embodiment, the mask plate 3 is attached integrally with the substrate Sw and is conveyed together with the substrate Sw by the substrate transfer device 2. The mask plate 3 may be fixedly arranged in the vacuum chamber 1 in advance. A plurality of openings 31 penetrating in the plate thickness direction are formed in the mask plate 3, and a predetermined pattern is formed by limiting the vapor deposition range of the evaporated organic material Mv on the substrate Sw at a position where these openings 31 do not exist. A film is formed (evaporated) on the substrate Sw. As the mask plate 3, a metal such as Invar, aluminum, alumina or stainless steel, or a resin such as polyimide is used. The vapor deposition source DS of the present embodiment is provided on the bottom surface of the vacuum chamber 1 so as to face the substrate Sw.

The vapor deposition source DS has a crucible 4 that constitutes the outer container of the present embodiment. The crucible 4 has a bottomed tubular contour with an open upper surface in the vertical direction, has good thermal conductivity such as molybdenum, titanium, stainless steel, and carbon, and is formed of a material having a high melting point. In this case, in the present embodiment, the upper surface opening 41 of the crucible 4 constitutes a spout of the evaporated organic material Mv. Around the crucible 4, a heating means Ht made of a known material such as a sheath heater or a lamp heater is provided. Then, the tubular body 5 constituting the inner container of the present embodiment is inserted into the crucible 4. The tubular body 5 is made of a porous body made of a material having good thermal conductivity and a high melting point, specifically, a carbon-based material having a plurality of pores 5a and having a predetermined porosity, for example, graphite. , It is formed to have a bottomed tubular contour. The porosity of the tubular body 5 is appropriately set according to the viscosity of the organic material Ms used for vapor deposition when melted, and is set in the range of 20 to 40% when the organic material Ms is α-NPD. Will be done.

A plurality of rod-shaped leg pieces 52 are erected on the outer bottom wall (outer lower wall) 51 of the tubular body 5 at intervals. Further, a plurality of rod-shaped spacer members 54 are erected on the outer peripheral wall 53 of the tubular body 5 at the same height position from the crucible 4 and at intervals in the circumferential direction. When the tubular body 5 is installed in the crucible 4 in the vacuum chamber 1 under atmospheric pressure, the tubular body 5 is inserted into the upper surface opening 41 of the crucible 4 from the leg piece 52 side, and each spacer member 54 is inserted into the crucible. The tubular body 5 is moved downward while sliding along the inner peripheral surface 43 of 4. Then, when each leg piece 52 comes into contact with the inner bottom surface 42 of the crucible 4, the tubular body 5 is concentrically positioned and installed in the crucible 4, and then the tubular body 5 is filled with the solid organic material Ms. In this state, a first space 6a composed of a gap W1 corresponding to the length of the spacer member 54 is defined between the inner peripheral surface 43 of the crucible 4 and the outer peripheral wall 53 of the tubular body 5, and in addition to this. A second space 6b composed of a gap W2 corresponding to the length of the leg piece 52 is defined between the inner bottom surface 42 of the crucible 4 and the outer bottom wall 51 of the tubular body 5. In this way, the tubular body 5 is inserted into the crucible 4 with the leg piece 52 side down, and the leg piece 52 is brought into contact with the inner bottom surface 42 of the crucible 4, and the tubular body 5 is inserted into the crucible 4. Can be easily positioned and set concentrically, which is advantageous.

The length of the leg piece 52 and the spacer member 54 can be efficiently heated by radiation from the crucible 4 when the crucible 4 is heated by the heating means Ht in a state where the vacuum chamber 1 is in a vacuum atmosphere, while the first space. Due to the conductance of 6a and the second space 6b, vaporized material from the wall surfaces 51 and 53 of the tubular body 5 and the holes 5a passes through the first space 6a and the second space 6b to the upper surface opening 41 of the crucible 4 as described later. It is set in the range of 1 mm to 30 mm so that it can be efficiently guided. Examples of the organic material Ms used for vapor deposition in the vapor deposition source DS of the present embodiment include α-NPD, and the powdered material is filled from the upper surface opening of the tubular body 5.

Here, when the crucible is filled with, for example, a powdery vapor-deposited substance in the above-mentioned conventional vapor deposition source and the crucible is heated by a heating means in a vacuum atmosphere, the vapor-deposited substance in the crucible is melted and then vaporized. , The vaporized material vaporizes only from the liquid surface facing the top opening of the crucible. As a result, there is a problem that the amount of evaporation per unit time under the same pressure is small and the deposition rate for the material to be deposited is low (that is, the productivity is low). On the other hand, in the vapor deposition source DS of the present embodiment, when the organic material Mv is vapor-deposited on the substrate Sw in a vacuum atmosphere, when the crucible 4 is heated by the heating means Ht, the radiant heat from the crucible 4 is shown in FIG. The tubular body 5 is heated, and the solid organic material Ms is melted by heat transfer from the heated tubular body 5 to form a liquid phase. At this time, since the tubular body 5 is composed of a porous body, the melted liquid organic material Ml impregnates each pore 5a of the tubular body 5 and the impregnated one (bleeds from each pore 5a). (Including those that come out and stay on the wall surfaces 51 and 53 of the tubular body 5) are vaporized by the radiant heat from the crucible 4, and this vaporized organic material Mv is transferred to the inner peripheral surface 43 of the crucible 4 and the outer peripheral wall of the tubular body 5. Each of these first and second spaces 6a is provided by the conduction of the first space 6a between the 53 and the second space 6b between the inner bottom wall 42 of the crucible 4 and the outer bottom wall 51 of the tubular body 5. , 6b is guided to the upper surface opening 41 of the crucible 4, and is scattered toward the substrate Sw.

As described above, in the present embodiment, the material vaporized from the liquid surface of the tubular body 5 facing the upper surface opening 41 of the crucible 4 is added to the material vaporized from the wall surfaces 51, 53 and the holes 5a of the tubular body 5. The amount of evaporation can be dramatically increased as compared with that of the above-mentioned conventional example, and the vapor deposition rate with respect to the substrate Sw can be increased. As a result, the vapor deposition source DS of the present embodiment can obtain a high vapor deposition rate even at a low heating temperature. Here, according to the experiment of the present inventor, when the organic material Ms is α-NPD and the tubular body 5 as the inner container is made of graphite having a porosity of 35%, it is the same as that of the above-mentioned conventional example. It was confirmed that a vapor deposition rate about twice as high was obtained in comparison. By heating the crucible 4 with the heating means Ht, when the molten organic material Ml impregnates the pores 5a of the tubular body 5, even if a part of the melted organic material Ml exudes, the tubular body exudes. Those that stay on the wall surfaces 51 and 53 of 5 and those that have fallen on the inner bottom wall 42 of the crucible 4 are quickly vaporized by radiation and heat transfer from the crucible 4, so that no particular problem occurs.

Although the embodiments of the present invention have been described above, various modifications can be made without departing from the scope of the technical idea of the present invention. In the above embodiment, a carbon-based material such as graphite has been described as an example of the porous body constituting the inner container, but the present invention is not limited to this, and SiC or the like can be used. Further, in the above embodiment, the outer container is described by using a crucible 4 having an open upper surface as an example, but in order to adjust the conductance of the first space 6a and the second space 6b, the upper surface of the crucible 4 is formed. , A lid provided with at least one injection nozzle may be attached. In this case, as the outer container, although not particularly illustrated and described, a container in which injection nozzles are arranged in a row on the upper surface of the storage box (so-called line source) can also be used.

DS ... Vapor deposition source for vacuum vapor deposition equipment, Dm ... Vacuum vapor deposition equipment, Ms ... Solid organic material (solid vapor deposition material), Ml ... Melted organic material (deposited material), Mv ... Vaporized organic material (evaporated vapor deposition) Material), 1 ... Vacuum chamber, 4 ... Vapor deposition (outer container), 41 ... Top opening (spout), 5 ... Cylindrical body (inner container), 51 ... Cylindrical outer bottom wall (outer and lower of inner container) Wall), Ht ... heater (heating means), Sw ... substrate (deposited material).

Claims (3)

A vapor deposition source for a vacuum vapor deposition apparatus that is placed in a vacuum chamber to evaporate a solid vapor deposition material and deposit it on an object to be deposited.
An outer container having an outlet for ejecting the vapor-deposited material evaporated toward the object to be vapor-deposited, an inner container inserted into the outer container at intervals from the wall surface and accommodating the solid-deposited material, and an inner container. A vapor deposition source for a vacuum vapor deposition apparatus, which comprises a heating means capable of heating the vapor deposition material of the above, and the inner container is composed of a porous body. The vapor deposition source for the vacuum vapor deposition apparatus according to claim 1, wherein the outer container is composed of a crucible having an upper surface in the vertical direction.
The inner container has a bottomed tubular contour with an open upper surface, and a leg piece is provided on the outer lower wall thereof, which is a vapor deposition source for a vacuum vapor deposition apparatus. The vapor deposition source for a vacuum vapor deposition apparatus according to claim 1 or 2, wherein the inner container is made of a carbon-based material having a predetermined porosity.

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