TWI835441B - Crucible for evaporation, evaporation source and evaporation device - Google Patents

Abstract

The present invention provides a crucible for vapor deposition, a vapor deposition source and a vapor deposition device equipped with the crucible for vapor deposition, which can suppress the deposition of the vapor deposition material into the opening and its surroundings, thereby stably diffusing the vapor deposition material. The vapor deposition crucible has an opening and is heated by induction heating, and the opening side portion is made of a material whose temperature rise due to induction heating is larger than that of other parts.

Description

Crucible for evaporation, evaporation source and evaporation device

The present invention relates to a crucible for vapor deposition, a vapor deposition source and a vapor deposition device.

Metal electrode wiring, organic electroluminescence (EL) layers, semiconductor layers, other organic material films, inorganic material films, etc. of display panels, solar cells, etc. are sometimes formed by evaporation such as vacuum evaporation. A vapor deposition device that performs such vapor deposition usually includes a vapor deposition source (also called an evaporation source, etc.) that heats a solid vapor deposition material at room temperature and sprays the vaporized vapor deposition material toward the substrate surface, and a device that holds the substrate. substrate holding part, etc. The vapor deposition source includes a crucible for storing the vapor deposition material, and a heating device for directly or indirectly heating and vaporizing the vapor deposition material. As a heating device for a vapor deposition source, a device using induction heating is known (see Patent Documents 1 and 2). Compared with resistance heating, induction heating has the advantages of high heating efficiency and excellent thermal responsiveness.

existing technical documents

Patent document 1: Japanese Patent Publication No. 2011-52301

Patent document 2: Japanese Patent Publication No. 2020-176298

However, in the induction heating method using a coil, the magnetic field is strongest in the center part of the coil, and the center part is most easily heated. When the coil is arranged to cover the periphery of the crucible and the crucible is heated by induction heating, the temperature of the opening of the crucible and its periphery is lower than that of the center because the magnetic field is relatively weak and open. Therefore, when the vapor deposition material contained in the crucible is vaporized by heating and diffuses outside the crucible, part of the vapor deposition material is likely to precipitate at the opening of the crucible and its surroundings. The evaporation material precipitated in and around the opening of the crucible may hinder the diffusion of the evaporation material and cause clogging.

In view of the above problems, the main object of the present invention is to provide a crucible for vapor deposition, a vapor deposition source and a vapor deposition device equipped with the crucible for vapor deposition, which can suppress the deposition of the vapor deposition material into the opening and its surroundings, thereby making the vapor deposition material Stable diffusion.

The vapor deposition crucible (A) of the present invention that solves the above problems is a vapor deposition crucible that has an opening and is heated by induction heating. The opening side part has a greater temperature rise due to transmission induction heating than other parts. form.

Another vapor deposition crucible (B) of the present invention that solves the above problems is a vapor deposition crucible heated by induction heating. The opening side portion is formed of a ferromagnetic metal and the other portion is formed of a nonmagnetic metal.

In the vapor deposition crucible (A) and the vapor deposition crucible (B), it is preferable that the material forming the opening side portion and the material forming the other portion are both stainless steel.

In the crucible for vapor deposition (A) and the crucible for vapor deposition (B), it is preferable that the opening side portion has a narrow waist.

In order to solve the above problem, another vapor deposition source of the present invention is provided with the crucible for vapor deposition (A) or the crucible for vapor deposition (B), and is covered with the crucible for vapor deposition (A) or the crucible for vapor deposition ( B) The coil is configured in a surrounding manner.

Another aspect of the present invention that solves the above problems is a vapor deposition device provided with the vapor deposition source.

According to the present invention, it is possible to provide a crucible for vapor deposition, a vapor deposition source and a vapor deposition apparatus including the crucible for vapor deposition, which can suppress the deposition of the vapor deposition material into the opening and its surroundings, thereby stably diffusing the vapor deposition material.

Hereinafter, a crucible for vapor deposition, a vapor deposition source, and a vapor deposition apparatus according to one embodiment of the present invention will be described in detail with appropriate reference to the drawings.

(Crucible for evaporation)

The crucible 10 for vapor deposition in FIG. 1 is used as a vapor deposition source of a vapor deposition apparatus. The crucible 10 for vapor deposition is a container containing the vapor deposition material to be vaporized. The crucible 10 for vapor deposition is heated by induction heating. The crucible 10 for vapor deposition has a substantially cylindrical shape with a bottom. In the vapor deposition crucible 10 of FIG. 1 , the lower side is the bottom and the upper side is open. That is, the crucible 10 for vapor deposition has the opening 11 at the upper top end.

In the crucible for vapor deposition 10, an opening side portion 12 (the upper portion in Fig. 1) and The other part 13 (lower part in Figure 1) is made of different materials. The opening side portion 12 is a portion including the opening 11 , and may be, for example, a portion 10 to 50% from the opening 11 (the upper end in FIG. 1 ) based on the height of the vapor deposition crucible 10 . The opening side portion 12 of the vapor deposition crucible 10 has a narrow waist portion 14 . The other portion 13 is a portion other than the opening side portion 12 , that is, a portion on the bottom side. The other part 13 is a part mainly containing the vapor deposition material. However, the vapor deposition material may be accommodated in the opening side portion 12 .

In one embodiment of the present invention, the opening side portion 12 is formed of a material whose temperature rise due to induction heating is greater than that of the other portion 13 . The opening side portion 12 is formed of a material whose temperature rises larger than that of the other portion 13 when high-frequency induction heating with a frequency of 300 kHz is performed, for example. According to the vapor deposition crucible 10 in this manner, when induction heating using a coil is performed, the temperature of the opening side portion 12 is easily higher than that of the other portion 13, so the vaporized deposition material can be suppressed from being deposited into the opening 11 and its surroundings. , thereby stably diffusing the evaporated material. In addition, the opening 11 and its periphery may be part or all of the opening side portion 12 .

Materials for forming the opening side portion 12 and other portions 13 can be selected from conventionally known forming materials of vapor deposition crucibles, etc., and materials that satisfy the above conditions can be selected and used, taking into account the type of vapor deposition material, vaporization temperature, etc. The material forming the opening side portion 12 and the other portion 13 may be metal or non-metal (ceramics, oxide, carbon, etc.). In addition, when both the opening side portion 12 and the other portion 13 are made of metal, there is an advantage that they can be easily joined together. In addition, when the other part 13 is made of metal, even if the other part 13 is not sufficiently heated by induction heating, the temperature can be effectively increased by heat transfer from the opening side part 12, thereby evaporating the contained material. Material vaporizes.

The difficulty of temperature rise caused by induction heating is affected by the resistivity, magnetic permeability, etc. of the material. For example, the opening side portion 12 may be formed of a material with a higher resistivity than the other portions 13 . In addition, the opening side portion 12 may be formed of a material with a higher magnetic permeability than the other portion 13 . An example of the method in which the opening side portion 12 is formed of a material having a higher resistivity than the other portion 13 is that the opening side portion 12 is formed of carbon and the other portion 13 is formed of copper. In addition, in the example in which the opening side part 12 is formed of iron and the other part 13 is formed of copper, the opening side part 12 is formed of a material with a higher resistivity than the other part 13 , or the opening side part 12 is made of a material with a higher magnetic permeability than that of the other part 13 . The other parts 13 are made of high-quality materials. A typical method in which the opening side portion 12 is formed of a material with a higher magnetic permeability than the other portion 13 is to form the opening side portion 12 of a ferromagnetic material and the other portion 13 of a nonmagnetic material. In this aspect, it is preferable that the opening side portion 12 is formed of ferromagnetic metal and the other portion 13 is formed of non-magnetic metal.

In one embodiment of the present invention, the opening side portion 12 is formed of ferromagnetic metal, and the other portion 13 is formed of non-magnetic metal. With the vapor deposition crucible 10 of this type, when induction heating using a coil is performed, the temperature of the opening side portion 12 is likely to be higher than that of the other portion 13, so it is possible to suppress the vaporized deposition material from being deposited into the opening 11 and its surroundings. , thereby stably diffusing the evaporated material.

Examples of ferromagnetic metals include iron, nickel, ferritic stainless steel (JIS SUS430, etc.), martensitic stainless steel (JIS SUS410, etc.), austenitic-ferritic stainless steel (JIS SUS329J1, etc.), and precipitation solidification stainless steel. (JIS SUS630, etc.) etc.

Examples of nonmagnetic metals include titanium, copper, aluminum, and austenitic stainless steel (JIS SUS304, SUS316, SUS201, etc.). Titanium and austenitic stainless steel are preferred because they can be moderately heated.

In one embodiment of the present invention, it is preferable that the material forming the opening side portion 12 and the material forming the other portion 13 are both stainless steel. Specifically, it is preferable that the opening side portion 12 is made of ferritic stainless steel (JIS SUS430, etc.), martensitic stainless steel (JIS SUS410, etc.), austenitic-ferritic stainless steel (JIS SUS329J1, etc.), precipitation solidification stainless steel (JIS SUS630, etc.) ), etc., and other parts 13 are formed of austenitic stainless steel (JIS SUS304, SUS201, etc.), etc. In this way, when the material forming the opening side portion 12 and the material forming the other portion 13 are both stainless steel, the opening side portion 12 and the other portion 13 can be joined relatively easily and firmly through welding or the like. In addition, since there are ferromagnetic and non-magnetic stainless steels, stainless steel is suitably used as the material for forming the vapor deposition crucible 10 .

As described above, the narrow waist 14 is formed in the opening side portion 12 of the vapor deposition crucible 10 . That is, the opening side portion 12 has a portion with a narrow diameter. According to the inventor's opinion, by providing the narrow waist 14 at the opening side portion 12 of the vapor deposition crucible 10, advantages such as uniform diffusion of the vapor deposition material without being affected by the amount of the vapor deposition material, the degree of heating, etc. can be obtained. . On the other hand, in a conventional crucible having such a narrow waist portion at the opening side, the vapor deposition material is particularly likely to precipitate on the narrow waist portion, thereby easily causing clogging. Therefore, when the present invention is applied to a crucible for vapor deposition having a narrow waist, the advantage of being able to suppress precipitation of the vapor deposition material into the opening of the crucible and its periphery (such as the narrow waist) can be particularly significantly obtained.

The height of the vapor deposition crucible 10 may be, for example, in the range of 36 mm or more and 190 mm or less. The diameter (inner diameter) of the vapor deposition crucible 10 may be, for example, in the range of 9 mm or more and 45 mm or less. The diameter (inner diameter) of the vapor deposition crucible 10 may be the diameter (inner diameter) of the other part 13 or the bottom. The ratio of the diameter (inner diameter) of the waist portion 14 to the diameter (inner diameter) of the vapor deposition crucible 10 may be, for example, in the range of 0.1 or more and 0.9 or less, or in the range of 0.2 or more and 0.7 or less. The average thickness of the side wall of the vapor deposition crucible 10 may be, for example, in the range of 0.3 mm or more and 1 mm or less.

When the vapor deposition crucible 10 is used for vapor deposition, the vapor deposition material is contained in the vapor deposition crucible 10 . The vapor deposition material is not particularly limited, and examples thereof include organic materials used to form organic EL layers, and inorganic materials used to form semiconductor layers, metal wiring, etc. In this way, the crucible 10 for vapor deposition can be used in both organic vapor deposition and inorganic vapor deposition.

Taking the vaporization efficiency into consideration, a granular heat transfer medium that is thermally and chemically stable and has a higher thermal conductivity than the vapor deposition material is housed in the vapor deposition crucible 10 together with the vapor deposition material. Alternatively, a composite material composed of a granular heat transfer medium and a vapor deposition material covering the heat transfer medium is accommodated in the vapor deposition crucible 10 . In addition, the heating medium heated by induction heating may be accommodated in the vapor deposition crucible 10 together with the vapor deposition material.

(Evaporation source)

The vapor deposition source 20 in FIG. 2 includes a crucible 10 for vapor deposition, a coil 21 arranged to cover the periphery of the crucible 10 for vapor deposition, and a power supply device 22 connected to the coil 21 . The coil 21 is arranged so that the central axis A of the vapor deposition crucible 10 coincides with the central axis A of the coil 21 . The specific form of the vapor deposition crucible 10 included in the vapor deposition source 20 is as described above.

The coil 21 is used to inductively heat the crucible 10 for vapor deposition. The coil 21 may be a known cylindrical coil in which electric wires are spirally wound.

The power supply device 22 is connected to the coil 21 and usually supplies alternating current to the coil 21 . The power supply device 22 is connected to a commercial power supply, etc., and usually generates alternating current of a predetermined frequency. The frequency of the current supplied from the power supply device 22 to the coil 21 is not particularly limited, and can be set according to the material forming the vapor deposition crucible 10 , for example, it can be in the range of several tens to several hundred kHz, or in the range of 100 to 600 kHz. , or it can be in the range of 300 to 500kHz.

According to the vapor deposition source 20 , during induction heating by causing current to flow through the coil 21 , the temperature of the opening side portion 12 of the vapor deposition crucible 10 is likely to be higher than that of the other portion 13 , so the vaporization of the vapor can be suppressed. The plating material precipitates toward the opening 11 and its surroundings, thereby stably diffusing the vapor deposition material.

The vapor deposition source has a structure including a vapor deposition material storage chamber and a diffusion chamber, for example. In this case, the vapor deposition crucible containing the vapor deposition material is placed in the vapor deposition material storage chamber with its periphery covered by the coil. The diffusion chamber is connected with a nozzle for spraying evaporation material. In this type of vapor deposition source, the vapor deposition material in the vapor deposition crucible that is vaporized by heating moves from the vapor deposition material storage chamber to the diffusion chamber. The gaseous vapor deposition material moved to the diffusion chamber is sprayed from the nozzle. For example, the nozzle may be arranged on the upper surface of the diffusion chamber. The evaporation material storage chamber and the diffusion chamber may be integrated or may be configured separately. The vapor deposition source is configured such that the discharge amount of the vapor deposition material can be controlled using a power supply device and a valve provided on the flow path of the vapor deposition material.

(Vapor deposition device)

The vapor deposition apparatus 30 in FIG. 3 includes a vapor deposition source 20, a substrate holding part 31, and a vacuum chamber 32. Among the vapor deposition sources 20 , at least the vapor deposition crucible 10 , the coil 21 , and the substrate holding portion 31 are arranged in the vacuum chamber 32 . The power supply device 22 may be arranged outside the vacuum chamber 32 .

The vapor deposition source 20 (the vapor deposition crucible 10 arranged so that the coil 21 covers the surrounding area) is arranged below in the vacuum chamber 32 . The crucible 10 for vapor deposition contains the solid vapor deposition material X.

The substrate holding portion 31 is arranged above the vacuum chamber 32 . The substrate Y to be evaporated is placed facing downward in the substrate holding portion 31 . The material constituting the substrate Y is not particularly limited, and may be resin, metal, oxide, etc.

The vacuum chamber 32 can maintain an appropriate degree of vacuum in the space where evaporation is performed. That is, the evaporation device 30 may be a vacuum evaporation device. The vacuum chamber 32 includes a vacuum pump that reduces the pressure in the vacuum chamber 32 by discharging the gas in the vacuum chamber 32 , and a ventilation device that increases the pressure in the vacuum chamber 32 by injecting a certain amount of gas into the vacuum chamber 32 .

The evaporation device 30 can be used in the same manner as an existing evaporation device (for example, an existing vacuum evaporation device). According to the vapor deposition device 30 , it is possible to suppress the deposition of the vapor deposition material X into the opening of the vapor deposition crucible 10 and its surroundings during vapor deposition. Therefore, according to the vapor deposition device 30, vapor deposition can be performed stably for a long time.

(Other implementations)

The present invention is not limited to the above-described embodiments, and the structure may be modified within the scope of not changing the spirit of the present invention. For example, the shape of the vapor deposition crucible is not particularly limited and may be any shape other than a cylindrical shape. In addition, the crucible for vapor deposition may have a shape such that the opening side portion does not have a narrow waist.

The crucible for vapor deposition may be composed of three or more materials, for example. Even in this case, as long as the opening side part is formed of a material whose temperature rise due to induction heating is greater than that of any other part, or the opening side part is formed of a ferromagnetic metal and the other optional parts are formed of a nonmagnetic metal. Can. However, when there is a material connecting each material (between each part) between the opening side part and other parts, etc., the connecting material is not considered.

(Example)

Hereinafter, the content of this invention is demonstrated more concretely using an Example. In addition, the present invention is not limited to the following examples.

(Example 1)

A substantially cylindrical crucible with a narrow waist and a capacity of 2 cm ³ was produced with the opening side part made of SUS430, a ferromagnetic metal, and the other parts made of non-magnetic metal SUS316. The evaporation source of Example 1 was assembled using the crucible and the coil formed by spirally winding the wires at equal intervals.

(Example 2)

A crucible similar to the one produced in Example 1 was produced except that the capacity was 5 cm ³ . The evaporation source of Example 2 was assembled, and the conditions were the same as those of Example 1 except that the above-mentioned crucible was used.

(Comparative example 1)

The evaporation source of Comparative Example 1 was assembled in the same manner as in Example 1 except that a titanium crucible with a capacity of 2 cm ³ made of the same material was used.

(Comparative example 2)

The evaporation source of Comparative Example 2 was assembled in the same manner as in Example 2 except that a titanium crucible with a capacity of 5 cm ³ made of the same material was used.

(evaluation)

Regarding the vapor deposition sources of Examples 1 and 2 and Comparative Examples 1 and 2, the vapor deposition material was vaporized by containing the vapor deposition material in the crucible and performing induction heating. Alq3 (tris(8-hydroxyquinoline)aluminum) is used as the evaporation material, and induction heating is performed by flowing an alternating current with a frequency of 350 kHz through the coil. In each of the vapor deposition sources of Comparative Examples 1 and 2, the vapor deposition material gradually precipitated around the opening, eventually causing clogging. However, in each of the vapor deposition sources of Examples 1 and 2, there was no vapor deposition around the opening. Material segregates.

Industrial applicability

The crucible for vapor deposition, the vapor deposition source, and the vapor deposition device of the present invention can be favorably used for film formation of metal electrode wiring, semiconductor layers, organic EL layers, other organic material thin films, and inorganic material thin films of display panels, solar cells, etc. .

10: Crucible for evaporation 11:Opening part 12: Opening side part 13:Other parts 14: thin waist 20: Evaporation source 21: coil 22:Power supply device 30: Evaporation device 31:Substrate holding part 32: Vacuum chamber A:Central axis B: Imaginary surface perpendicular to central axis A X:Vapor deposition material Y:Substrate

FIG. 1 is a side view of a crucible for vapor deposition according to one embodiment of the present invention. FIG. 2 is a schematic side view of a vapor deposition source according to one embodiment of the present invention. FIG. 3 is a schematic diagram showing a vapor deposition apparatus according to an embodiment of the present invention.

10: Crucible for evaporation

11:Opening part

12: Opening side part

13:Other parts

14: thin waist

A:Central axis

B: Imaginary surface perpendicular to central axis A

Claims (7)

A crucible for vapor deposition, which has an opening and is heated by induction heating. The crucible for vapor deposition is characterized in that a portion on the side of the opening is made of a material that has a greater temperature rise due to induction heating than other parts, and the opening is formed The material of the side parts and the material forming the other parts mentioned above is all stainless steel. The vapor deposition crucible according to claim 1, wherein the opening side portion has a narrow waist. A crucible for vapor deposition, which is heated by induction heating. The crucible for vapor deposition is characterized in that the opening side part is formed of a ferromagnetic metal, and the other part is formed of a non-magnetic metal, and the opening side part has a thin waist. . The vapor deposition crucible according to claim 3, wherein the material forming the opening side portion and the material forming the other portion are both stainless steel. The vapor deposition crucible according to claim 3, wherein the material forming the opening side portion is iron, nickel, ferritic stainless steel, martensitic stainless steel, austenitic-ferritic stainless steel, or precipitation solidified stainless steel. It is stainless steel, and the material forming the other parts mentioned above is titanium, copper, aluminum or austenitic stainless steel. A vapor deposition source characterized by including: the crucible for vapor deposition according to any one of claims 1 to 5; and a coil arranged to cover the periphery of the crucible for vapor deposition. A vapor deposition device, comprising the vapor deposition source according to claim 6.