Evaporation source, film forming apparatus, and film forming method

Abstract

The invention provides an evaporation source, a film forming apparatus, and a film forming method capable of suppressing variation of film forming characteristics. An evaporation source (300) that forms a film while moving relative to a substrate is characterized by comprising: a nozzle (332) that ejects a film-forming material (M) accommodated in a material container, said material being evaporated or sublimated by being heated; and a cylindrical member (333) disposed so as to surround the outer periphery of the nozzle (332).

Description

Technical Field

[0001] The present invention relates to an evaporation source, a film forming apparatus, and a film forming method. Background Art

[0002] In a film forming apparatus for forming a thin film on a substrate, there is known a technique of ejecting a film forming material from a plurality of nozzles while moving an evaporation source to form a film. According to this technique, a thin film can be appropriately formed even on a large-sized substrate. Patent Document 1 discloses the following technique: a technique of suppressing a temperature drop of a plurality of nozzles by disposing a reflector that is provided at a plurality of evaporation source nozzles and protrudes to a part outside the plurality of evaporation source nozzles.

[0003] [Prior Art Documents]

[0004] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-146658 Summary of the Invention

[0006] However, in the structure of Patent Document 1, the temperature drop of the nozzles cannot be sufficiently suppressed, and due to the temperature drop of the nozzles, materials are likely to accumulate on the nozzles. As a result, the film forming characteristics may become uneven. An object of the present invention is to provide an evaporation source, a film forming apparatus, and a film forming method capable of suppressing unevenness in film forming characteristics.

[0007] [Means for Solving the Problem]

[0008] The present invention employs the following means to solve the above problems.

[0009] That is, the evaporation source of the present invention is an evaporation source that forms a film while relatively moving with respect to a substrate, and is characterized by including:

[0010] a nozzle that ejects a film forming material stored in a material container through a material that has been evaporated or sublimated by heating; and

[0011] a cylindrical member that is disposed to surround the outer periphery of the nozzle.

[0012] Advantages of the Invention

[0013] As described above, according to the present invention, unevenness in film forming characteristics can be suppressed. Brief Description of the Drawings

[0014] Figure 1 It is a schematic configuration diagram of a film forming apparatus according to an embodiment of the present invention.

[0015] Figure 2 It is a schematic configuration diagram of a film forming apparatus according to an embodiment of the present invention.

[0016] Figure 3 It is a cross-sectional schematic view of an evaporation source according to an embodiment of the present invention.

[0017] Figure 4 It is a cross-sectional schematic view of an evaporation source according to an embodiment of the present invention.

[0018] Figure 5 It is an explanatory diagram of a modified example of an evaporation source according to an embodiment of the present invention.

[0019] Figure 6 It is an explanatory diagram of a method for manufacturing an electronic device. Detailed Description of the Invention

[0020] Hereinafter, with reference to the accompanying drawings, exemplary and detailed descriptions will be given of the embodiments for implementing the present invention. However, regarding the dimensions, materials, shapes, relative arrangements, etc. of the structural components described in this embodiment, unless otherwise specifically specified, the scope of the present invention is not intended to be limited thereto. In the following description, the moving direction of the evaporation source is set as the first direction X, and the direction intersecting the first direction X is set as the second direction Y. It should be noted that in each embodiment, more specifically, the second direction Y is a direction orthogonal to the first direction X and parallel to the film-forming surface of the substrate on which film formation is performed.

[0021] (Embodiment)

[0022] Refer to Figures 1 to 5 , and an evaporation source according to an embodiment of the present invention, a film-forming apparatus including the evaporation source, and a film-forming method using the evaporation source will be described.

[0023] <Film-Forming Apparatus>

[0024] Refer to Figure 1 and Figure 2 , and the film-forming apparatus 10 of the present embodiment will be described. Figure 1 It is a schematic structural diagram of a film-forming apparatus according to an embodiment of the present invention, briefly showing the structure observed from the front side. Figure 2 It is a schematic structural diagram of a film-forming apparatus according to an embodiment of the present invention, briefly showing the structure observed from above. It should be noted that in Figure 1 and Figure 2 , the main structures are shown in perspective.

[0025] The film forming apparatus 10 of this embodiment is an evaporation coating apparatus for performing vacuum evaporation. The film forming apparatus 10 includes: a chamber 100, a vacuum pump 200 for making the inside of the chamber 100 into a vacuum (reduced pressure atmosphere), and an evaporation source 300 disposed inside the chamber 100. The evaporation source 300 undertakes the function of evaporating or sublimating the film forming material M that is evaporated onto the substrate S disposed inside the chamber 100 by heating. The material evaporated or sublimated by the evaporation source 300 adheres to the substrate S, thereby forming a thin film on the substrate S.

[0026] In addition, the film forming apparatus 10 includes: an atmosphere box 410 for supplying power or coolant to the evaporation source 300, and a first atmosphere arm 420 and a second atmosphere arm 430 that are driven following the movement of the atmosphere box 410. The inside of the atmosphere box 410 is formed of a cavity and is configured to communicate with the outside of the chamber 100 through the inside of the first atmosphere arm 420 and the second atmosphere arm 430. Therefore, the inside of the atmosphere box 410 is in a state of being exposed to the atmosphere. By adopting such a structure, the wiring connected to the power supply provided outside the chamber 100 and the cooling pipe connected to the coolant supply device provided outside the chamber 100 can be connected to the evaporation source 300.

[0027] The first atmosphere arm 420 and the second atmosphere arm 430 are provided for arranging the wiring and the cooling pipe in the cavity of the moving atmosphere box 410. That is, the first atmosphere arm 420 and the second atmosphere arm 430 are configured to operate following the movement of the atmosphere box 410, and their inside is formed of a cavity. More specifically, one end of the second atmosphere arm 430 is configured to be rotatable relative to the bottom plate of the chamber 100. And in the first atmosphere arm 420, one end thereof is axially supported to be rotatable relative to the other end of the second atmosphere arm 430, and the other end thereof is axially supported to be rotatable relative to the atmosphere box 410.

[0028] In addition, a moving mechanism for moving the evaporation source 300 is provided in the film forming apparatus 10. The moving mechanism of this embodiment includes: a pair of guide rails 520, a pair of gears 510 provided on both sides of the rotating shaft penetrating the atmosphere box 410, and a driving source such as a motor (not shown) for rotating the rotating shaft. Rack teeth meshing with the pair of gears 510 are provided on the pair of guide rails 520. According to the above-described structure, by rotating the rotating shaft using the driving source, the evaporation source 300 can reciprocally move along the pair of guide rails 520 together with the atmosphere box 410.

[0029] As described above, the evaporation source 300 is configured to be guided by a pair of guide rails 520 and to linearly reciprocate along the first direction X. Further, by evaporating or sublimating the film-forming material M while moving the evaporation source 300 along the first direction X, a thin film can be formed on the substrate S. Note that film formation can be performed during the movement of the evaporation source 300 in at least either the forward path or the return path. In this way, the evaporation source 300 forms a film while relatively moving with respect to the substrate S.

[0030] As described above, in the moving mechanism of the present embodiment, a so-called rack and pinion mechanism is shown. However, the moving mechanism for reciprocating the atmospheric chamber 410 and the evaporation source 300 is not limited to the rack and pinion mechanism, and various known techniques such as a ball screw mechanism can also be used.

[0031] In addition, in the film-forming apparatus 10 of the present embodiment, film thickness monitors 600 for measuring the film thickness of the film formed on the substrate S are provided on both sides of the evaporation source 300 in the second direction Y. The film thickness monitor 600 measures the film thickness of the film formed on the film thickness monitor 600, predicts the film thickness of the film formed on the substrate S based on this film thickness, and thereby measures the film thickness of the film formed on the substrate S. The film formation amount (for example, the heating amount of the film-forming material M in the evaporation source 300) is controlled based on the film thickness measured by the film thickness monitor 600, and thereby the thickness of the thin film formed on the substrate S can be made the desired thickness.

[0032] <Evaporation Source>

[0033] Refer to Figure 3 and Figure 4 , and the evaporation source 300 of the embodiment of the present invention will be described. Figure 3 and Figure 4 are schematic cross-sectional views of the evaporation source of the embodiment of the present invention. Figure 3 is a view schematically showing a cross-section obtained by cutting the evaporation source 300 with a plane perpendicular to the second direction Y and passing through the nozzle center, Figure 4 is a view schematically showing a cross-section obtained by cutting the evaporation source 300 with a plane perpendicular to the first direction X and passing through the nozzle center. Note that although a large number of nozzles are provided (in Figure 1 and Figure 2 a case where 14 nozzles are provided is shown), for ease of explanation, Figure 4 only 4 nozzles are shown in

[0034] The evaporation source 300 includes a rectangular parallelepiped-shaped housing. The housing has a housing main body 311 and a lid portion 312. The housing main body 311 has a bottom plate portion and four side plate portions. The lid portion 312 closes most of the upper opening portion of the housing main body 311. The housing main body 311 has a heat dissipation function. For example, a passage (flow path) is formed in advance inside the housing main body 311, and by circulating a coolant such as cooling water through this passage, a heat dissipation effect can be exerted.

[0035] In addition, the evaporation source 300 includes a material container (crucible) assembled inside the housing. The material container includes a lower crucible 320 that forms a material chamber 321 and an upper crucible 330 that forms a diffusion chamber 331. A plurality of nozzles 332 are provided on the upper surface of the upper crucible 330. The lower crucible 320 and the upper crucible 330 are fixed by fixing tools B such as bolts in a state where an intermediate plate 340 is clamped therebetween. The intermediate plate 340 has an introduction pipe 341 for communicating the material chamber 321 and the diffusion chamber 331. The material chamber 321 is a chamber used for storing the film-forming material M. In addition, the diffusion chamber 331 is a chamber that diffuses the material that has been evaporated or sublimated by heating the film-forming material stored in the material chamber 321 before reaching the plurality of nozzles 332 to adjust the pressure distribution and is used to adjust the inflow amount to the plurality of nozzles 332. The material that has been evaporated or sublimated in the interior of the material chamber 321 is guided into the interior of the diffusion chamber 331 through the introduction pipe 341, diffused, and ejected into the chamber 100 from the plurality of nozzles 332. The material container configured as described above is fixed to the housing in a state of being positioned inside the housing by being supported by a support member 350.

[0036] In addition, the evaporation source 300 includes a first heater 361 for heating the lower crucible 320 and a second heater 362 for heating the upper crucible 330. It should be noted that the first heater 361 is provided between the outer wall surface of the lower crucible 320 and the inner wall surface of the housing main body 311, and the second heater 362 is provided between the outer wall surface of the upper crucible 330 and the inner wall surface of the housing main body 311. It should be noted that although not particularly illustrated, the first heater 361 and the second heater 362 are also provided on the front side and the back side of the paper surface. That is, these first heater 361 and second heater 362 are provided so as to respectively surround the outer wall surfaces of the lower crucible 320 and the upper crucible 330. As the first heater 361 and the second heater 362, components that generate heat by energization such as a sheathed heater can be preferably applied. By the first heater 361, the film-forming material M stored in the lower crucible 320 is heated and evaporated or sublimated. In addition, by the second heater 362, it is possible to suppress the solidification of the evaporated or sublimated material in the diffusion chamber 331 of the upper crucible 330.

[0037] Furthermore, in the evaporation source 300, reflectors 371, 372, 373, and 374 are respectively provided between the bottom surface of the housing main body 311 and the material container, between the lower surface of the lid portion 312 and the material container, between the first heater 361 and the second heater 362, and between the inner wall surface of the housing main body 311 and the material container. Through these reflectors 371, 372, 373, and 374, heat from the first heater 361 and the second heater 362 can be suppressed from being transferred to the housing, so that the material chamber 321 and the diffusion chamber 331 can be efficiently heated, and heat escape to the outside of the housing can be suppressed. It should be noted that by adopting a structure in which a plurality of reflectors are arranged and configured between the housing main body 311 and various components, the heating efficiency can be further improved.

[0038] <Detailed Structure near Nozzle>

[0039] The detailed structure near the nozzle 332 will be described. In the evaporation source 300 of the present embodiment, a plurality of cylindrical members 333 are provided so as to respectively surround the outer circumferences of the plurality of nozzles 332. In Figure 4 the upper part of the cross-sectional view, a part of the top view of the vicinity of the nozzle 332 observed from above is shown. As shown in this figure, in the present embodiment, the cylindrical member 333 has a cylindrical shape, but as long as it is cylindrical, its shape is not limited. These plurality of cylindrical members 333 are integrally provided on the material container by being fixed to the material container (more specifically, the upper crucible 330). It should be noted that through holes 312a are respectively provided at the positions where the plurality of nozzles 332 and the cylindrical members 333 are provided in the lid portion 312. Thus, the nozzle 332 and the cylindrical member 333 are configured to pass through the through hole 312a and their front ends protrude upward compared to the upper surface of the lid portion 312.

[0040] In addition, as Figure 5 (a), (b) show, a structure in which the reflector 372 disposed between the lower surface of the lid portion 312 and the material container is provided with a protruding portion 372a may also be adopted. The protruding portion 372a protrudes upward so as to face the outer wall surface of the cylindrical member 333. In the example shown in this figure, a structure in which the protruding portion 372a is arranged so as to surround the cylindrical member 333 is adopted. More specifically, the shape of the protruding portion 372a is a cylindrical shape. However, as long as the protruding portion 372a functions as a heat insulator, it does not necessarily need to surround the cylindrical member 333. In addition, in Figure 5 (a), (b) the example shown, the protruding portion 372a is configured to surround one cylindrical member 333. However, when the distance between adjacent nozzles 332 and the cylindrical member 333 is small, a structure in which a plurality of cylindrical members 333 are surrounded by one protruding portion 372a may also be adopted. In Figure 5(c) shows a structure in which two cylindrical members 333 are surrounded by a protrusion 372a, but a structure in which three or more cylindrical members 333 are surrounded by a protrusion 372a may also be employed.

[0041] <Method of Manufacturing an Electronic Device>

[0042] Next, an example of a method of manufacturing an electronic device using the evaporation source, film forming apparatus, and film forming method of the present embodiment will be described. Hereinafter, the structure of an organic EL display device will be shown as an example of an electronic device, and a method of manufacturing the organic EL display device will be illustrated.

[0043] First, the manufactured organic EL display device will be described. Figure 6 (a) is an overall view of the organic EL display device 150, Figure 6 (b) shows a cross-sectional structure of one pixel.

[0044] As shown in Figure 6 (a), in the display area 151 of the organic EL display device 150, a plurality of pixels 152 each including a plurality of light emitting elements are arranged in a matrix. Each light emitting element has a structure including an organic layer sandwiched between a pair of electrodes, which will be described in detail later. It should be noted that the pixel as used herein refers to the smallest unit capable of displaying a desired color in the display area 151. In the case of the organic EL display device of the present embodiment, the pixel 152 is constituted by a combination of a first light emitting element 152R, a second light emitting element 152G, and a third light emitting element 152B that emit mutually different lights. The pixel 152 is mostly constituted by a combination of a red light emitting element, a green light emitting element, and a blue light emitting element, but may also be a combination of a yellow light emitting element, a cyan light emitting element, and a white light emitting element, as long as it is at least one color or more, and there is no particular limitation.

[0045] Figure 6 (b) is Figure 6(a) Schematic diagram of a partial cross-section at the A - B line. Pixel 152 is composed of a plurality of light-emitting elements. Each light-emitting element has a first electrode (anode) 154, a hole transport layer 155, any one of light-emitting layers 156R, 156G, 156B, an electron transport layer 157, and a second electrode (cathode) 158 on a substrate 153. Among them, the hole transport layer 155, the light-emitting layers 156R, 156G, 156B, and the electron transport layer 157 are equivalent to organic layers. In addition, in this embodiment, the light-emitting layer 156R is an organic EL layer that emits red light, the light-emitting layer 156G is an organic EL layer that emits green light, and the light-emitting layer 156B is an organic EL layer that emits blue light. The light-emitting layers 156R, 156G, 156B are respectively formed into patterns corresponding to the light-emitting elements (sometimes also described as organic EL elements) that emit red, green, and blue light. In addition, the first electrode 154 is separately formed according to each light-emitting element. The hole transport layer 155, the electron transport layer 157, and the second electrode 158 can be formed jointly in a plurality of light-emitting elements 152R, 152G, 152B, or can be formed according to each light-emitting element. It should be noted that an insulating layer 159 is provided between the first electrodes 154 to prevent short circuits between the first electrode 154 and the second electrode 158 due to impurities. In addition, since the organic EL layer deteriorates due to moisture or oxygen, a protective layer 140 is provided to protect the organic EL element from moisture or oxygen.

[0046] In Figure 6 (b), the hole transport layer 155 or the electron transport layer 157 is represented by one layer, but according to the structure of the organic EL display element, it can also be formed by a plurality of layers including a hole blocking layer or an electron blocking layer. In addition, a hole injection layer can also be formed between the first electrode 154 and the hole transport layer 155, and the hole injection layer has an energy band structure that can smoothly inject holes from the first electrode 154 into the hole transport layer 155. Similarly, an electron injection layer can also be formed between the second electrode 158 and the electron transport layer 157.

[0047] Next, an example of the manufacturing method of the organic EL display device will be specifically described.

[0048] First, a substrate 153 on which a circuit (not shown) for driving the organic EL display device and the first electrode 154 are formed is prepared.

[0049] An acrylic resin is formed by spin coating on the substrate 153 on which the first electrode 154 is formed, and the acrylic resin is patterned by photolithography to form an insulating layer 159 in such a way that an opening is formed in the portion where the first electrode 154 is formed. This opening portion corresponds to the light-emitting region where the light-emitting element actually emits light.

[0050] The substrate 153 with the insulating layer 159 formed thereon is fed into the first organic material film-forming apparatus, and the substrate is held by the substrate support table and the electrostatic chuck. The hole transport layer 155 is formed as a common layer on the first electrode 154 in the display region. The hole transport layer 155 is formed by vacuum evaporation. In fact, the hole transport layer 155 is formed to have a size larger than that of the display region 151, so a high-precision mask is not required.

[0051] Next, the substrate 153 on which the hole transport layer 155 has been formed is fed into the second organic material film-forming apparatus and held by the substrate support table and the electrostatic chuck. Alignment between the substrate and the mask is performed, the substrate is placed on the mask, and the red-emitting light-emitting layer 156R is formed on the portion of the substrate 153 where the red-emitting element is disposed.

[0052] In the same manner as the formation of the light-emitting layer 156R, the green-emitting light-emitting layer 156G is formed by the third organic material film-forming apparatus, and the blue-emitting light-emitting layer 156B is formed by the fourth organic material film-forming apparatus. After the formation of the light-emitting layers 156R, 156G, and 156B is completed, the electron transport layer 157 is formed over the entire display region 151 by the fifth film-forming apparatus. The electron transport layer 157 is formed as a common layer for the three-color light-emitting layers 156R, 156G, and 156B.

[0053] The substrate on which the electron transport layer 157 has been formed is moved in the metallic evaporation material film-forming apparatus to form the second electrode 158.

[0054] Then, it is moved to the plasma CVD apparatus to form the protective layer 140, and the organic EL display device 150 is completed.

[0055] From the feeding of the substrate 153 with the insulating layer 159 formed thereon into the film-forming apparatus to the completion of the formation of the protective layer 140, if it is exposed to an atmosphere containing moisture or oxygen, the light-emitting layer made of the organic EL material may deteriorate due to moisture or oxygen. Therefore, in this embodiment, the substrate is fed in and out between the film-forming apparatuses in a vacuum atmosphere or an inert gas atmosphere.

[0056] <Advantages of the evaporation source, film-forming apparatus, and film-forming method of this embodiment>

[0057] In the evaporation source 300 of the present embodiment, a plurality of cylindrical members 333 are provided that are configured to respectively surround the outer circumferences of the plurality of nozzles 332. Thereby, the temperature drop of the nozzles 332 can be suppressed, and thus the unevenness of the film formation characteristics can be suppressed. In particular, since the temperature drop at the front end of the nozzle 332 is suppressed, the accumulation of the material at the front end of the nozzle 332 can be suppressed. In addition, even in the nozzles 332 near the end where the temperature is likely to drop among the plurality of nozzles 332, the unevenness of the temperature of each nozzle 332 can be suppressed by suppressing the temperature drop. Thus, even when it is necessary to extend the length in the longitudinal direction of the evaporation source 300 along with the increase in the size of the substrate S on which the film is formed, the unevenness of the film formation characteristics can be suppressed.

[0058] For example, in the case of a large-sized substrate S with a width of 1310 mm in the X direction and a width of 2290 mm in the Y direction, the size of the evaporation source 300 is such that the width W1 in the X direction is about 850 mm and the width W2 in the Y direction is about 2600 mm. Even for such a large-sized evaporation source 300, the temperature drop of the nozzles 332 near the end in the Y direction can be suppressed, and the unevenness of the film formation characteristics can be suppressed. It should be noted that the following experiment was conducted: when 500 W of power was supplied to the first heater 361 and 600 W of power was supplied to the second heater 362 for heating, the maximum temperature and the minimum temperature among the plurality of nozzles 332 were compared between the evaporation source without the cylindrical member 333 and the evaporation source 300 with the cylindrical member 333. As a result, the temperature difference of the former was 52 °C, while the temperature difference of the latter was 37 °C. Thus, it can be confirmed that the temperature difference of the plurality of nozzles 332 can be suppressed by the evaporation source 300 of the present embodiment.

[0059] In addition, as described with reference to Figure 5 By adopting a structure in which a protruding portion 372a that protrudes upward is provided on the reflector 372 so as to face the outer wall surface of the cylindrical member 333, the temperature drop of the nozzle 332 can be further suppressed.

[0060] It should be noted that in Figure 4 and Figure 5 , although a structure in which the nozzle 332 extends straight in the vertical direction is shown, the extending direction of the nozzle 332 is not limited. For example, a structure in which the outer nozzles 332 among the plurality of nozzles 332 are provided to be inclined outward with respect to the vertical direction can also be adopted. In this case, for the cylindrical member 333 and the protruding portion 372a, it is preferably configured to be inclined outward with respect to the vertical direction (refer to Figure 1 ).

[0061] Description of Reference Numerals

[0062] 10: Film forming apparatus 100: Chamber 200: Vacuum pump 300: Evaporation source 311: Housing main body 312: Cover part 312a: Through hole 320: Lower crucible 321: Material chamber 330: Upper crucible 331: Diffusion chamber 332: Nozzle 333: Cylindrical member 340: Intermediate plate 341: Introduction pipe 350: Support member 361: First heater 362: Second heater 371, 372, 373, 374: Reflector 372a: Protrusion 410: Atmosphere box 420: First atmosphere arm 430: Second atmosphere arm 510: Gear 520: Guide rail 600: Film thickness monitor B: Fixing tool M: Film forming material S: Substrate

Claims

1. An evaporation source that forms a film while relatively moving with respect to a substrate, wherein the evaporation source is characterized in that, it includes: a nozzle that ejects a film-forming material stored in a material container as a material that has been evaporated or sublimated by heating; and a cylindrical member that is arranged to surround the outer periphery of the nozzle.

2. An evaporation source that forms a film while relatively moving with respect to a substrate, wherein the evaporation source is characterized in that, it includes: a plurality of nozzles that eject a film-forming material stored in a material container as a material that has been evaporated or sublimated by heating; and a plurality of cylindrical members that are arranged to respectively surround the outer peripheries of the plurality of nozzles.

3. The evaporation source according to claim 1 or 2, wherein, the cylindrical member is integrally provided on the material container.

4. The evaporation source according to claim 3, wherein, the evaporation source includes: a housing that houses the material container; and a reflector that is arranged between the housing and the material container, the reflector has a protruding portion that protrudes upward so as to face the outer wall surface of the cylindrical member.

5. The evaporation source according to claim 4, wherein, the protruding portion is arranged to surround the cylindrical member.

6. The evaporation source according to claim 1 or 2, wherein, the material container includes: a material chamber that stores the film-forming material; and a diffusion chamber that communicates with the material chamber and diffuses the film-forming material stored in the material chamber as a material that has been evaporated or sublimated by heating, the nozzle is provided on the upper surface of the diffusion chamber.

7. A film-forming apparatus, characterized in that, it includes: a chamber; the evaporation source according to claim 1 or 2, which is arranged in the chamber; and a moving mechanism that moves the evaporation source.

8. A film-forming method, characterized in that, it includes: a step of moving the evaporation source according to claim 1 or 2; and a step of ejecting a material that has been evaporated or sublimated through the evaporation source while moving the evaporation source.

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