Film forming apparatus, film forming method, and method for manufacturing electronic device

Abstract

The present invention provides: a film forming apparatus in which a mask can be stably cooled; a film forming method; and a method for manufacturing an electronic device.　The present invention specifically provides a film forming apparatus 1 for forming a thin film on a substrate S by the intermediary of a mask M with a film formation material that is discharged from a film formation source 110 within a chamber 10. This film forming apparatus 1 is characterized by being provided with a radiation cooling member 130, which has a cooling surface 131 that is capable of performing heat exchange by means of radiation, at a position not obstructing the path of the film formation material from the film formation source 110 to a film formation range R of the substrate S, and is also characterized in that the temperature of the radiation cooling member 130 is controlled according to the thickness of the film of the film formation material formed on the cooling surface 131.

Description

Film forming apparatus, film forming method, and method for manufacturing electronic device

[0001] The present invention relates to a film forming apparatus, a film forming method, and a method for manufacturing an electronic device.

[0002] Organic EL display devices (organic EL displays) are finding wider application in applications such as VR HMDs (Virtual Reality Head-Mounted Displays) as well as smartphones, televisions, and automotive displays. In particular, displays used in VR HMDs are required to form pixel patterns with high precision in order to reduce dizziness in users, and higher resolution is therefore required.

[0003] In the manufacture of organic EL display devices, when forming the organic light-emitting elements (organic EL elements; OLEDs) that make up the organic EL display device, a film-forming material emitted from a film-forming source is formed on a substrate through a mask on which a pixel pattern is formed, thereby forming an organic layer and a metal layer.

[0004] In this type of film formation method, the film formation source simultaneously emits thermal radiation energy as the film formation material is released. Thermal radiation from the film formation source causes the mask, in particular, to heat up and expand, changing the relative position between the mask and the substrate. If the relative position between the mask and the substrate changes during film formation, it becomes impossible to form pixel patterns with high precision, so cooling the mask, in particular, is necessary.

[0005] Generally, when cooling an object, three heat transfer modes are available: conduction, convection, and radiation. However, in the above-mentioned film formation method, because film formation is performed in a vacuum chamber, convection cannot be used and either conduction or radiation must be used. Of these, active use of heat conduction is difficult due to factors such as the tendency for in-plane thermal resistance to increase as masks become thinner with the increasing resolution of pixel patterns, and the difficulty of controlling the contact state with the substrate, resulting in variations in contact thermal resistance. Therefore, it is considered desirable to use radiation to cool the mask during the above-mentioned film formation process.

[0006] When radiatively cooling a mask, it is effective to place a radiant cooling element, whose surface can maintain a lower temperature than the heated portion of the mask, facing the heated portion of the mask near the heated portion. For example, Patent Document 1 discloses a technology relating to a radiant cooling element that hemispherically covers the heated portion of the mask. However, the technology disclosed in Patent Document 1 is intended for an EB exposure apparatus and does not anticipate the formation of a film on the surface of the radiant cooling element due to scattering of particles of film-forming material emitted from the film-forming source. In an operating environment where such a film is formed, problems arise, such as the need for periodic cleaning and changes in cooling capacity as the film thickness increases.

[0007] Furthermore, Patent Document 2 discloses a technique for arranging a radiant cooling member behind an adhesion shield that covers the entire interior of a chamber. In this technique, in a film formation apparatus, the radiant cooling member is arranged behind the adhesion shield to prevent the formation of a film on the surface of the radiant cooling member due to scattering of film formation material emitted from a film formation source. In this case, since the mask is cooled through the adhesion shield, the cooling function of the radiant cooling member is not fully exerted, and there are problems such as the cooling capacity changing as the thickness of the film formed on the surface of the adhesion shield increases.

[0008] JP 2000-349023 A JP 2021-080559 A

[0009] As described above, even if a radiation cooling member is provided in a film forming apparatus, the mask cannot be stably cooled due to the adhesion of film forming material, making it difficult to improve film forming accuracy.

[0010] An object of the present invention is to provide a film formation apparatus, a film formation method, and a method for manufacturing an electronic device that can stably cool a mask.

[0011] The film formation apparatus of the present invention is a film formation apparatus that forms a thin film on a substrate through a mask using a film formation material released from a film formation source within a chamber, and is characterized in that it is provided with a radiant cooling member that is installed at a position that does not obstruct the path of the film formation material from the film formation source to the film formation area on the substrate and has a cooling surface that is capable of heat exchange by radiation, and the temperature of the radiant cooling member is controlled according to the thickness of the film made of the film formation material formed on the cooling surface.

[0012] As described above, according to the present invention, the mask can be cooled stably.

[0013] Fig. 1 is a schematic configuration diagram of a film forming apparatus according to Example 1. Fig. 2 is a plan view of a radiant cooling member according to Example 1. Fig. 3 is a schematic cross-sectional view of a radiant cooling member etc. according to Example 1. Fig. 4 is a schematic cross-sectional view of a radiant cooling member etc. according to Example 1. Fig. 5 is a schematic configuration diagram of a film forming apparatus according to Example 2. Fig. 6 is an explanatory diagram of an organic EL display device.

[0014] The following detailed description of the present invention will be given by way of example with reference to the accompanying drawings, although the dimensions, materials, shapes, relative positions, etc. of the components described in the examples are not intended to limit the scope of the present invention unless otherwise specified.

[0015] (Example 1) A film formation apparatus, a film formation method, and a method for manufacturing an electronic device according to Example 1 of the present invention will be described with reference to Figures 1 to 4. Figure 1 is a schematic diagram of a film formation apparatus according to Example 1 of the present invention. In Figure 1, the internal configuration of the apparatus is shown generally, with some components shown in schematic cross-sectional views. Figure 2 is a plan view of a radiant cooling member according to Example 1 of the present invention. The cross-sectional view of the radiant cooling member in Figure 1 corresponds to the AA cross-section in Figure 2. Figures 3 and 4 are schematic cross-sectional views of a radiant cooling member etc. according to Example 1 of the present invention. Figure 3 is an explanatory diagram of heat exchange during film formation, and Figure 4 is a diagram showing the state of particles, which are the film formation material, during film formation.

[0016] <Film Forming Apparatus> The film forming apparatus 1 includes a chamber 10 and a film forming unit 100 disposed inside the chamber 10. The interior of the chamber 10 is configured to be able to maintain a vacuum atmosphere or an inert gas atmosphere. The film forming unit 100 includes a film forming source 110 that emits a film forming material, a limiting member 120 that limits the direction of irradiation of the film forming material, a radiant cooling member 130, and a film thickness meter 140. The film forming apparatus 1 according to this embodiment is a vacuum deposition apparatus, and the film forming source 110 is an evaporation source. The film forming material (evaporation material) evaporates or sublimes from the film forming source 110, passes through an opening in a mask M, and is deposited (evaporated) on a substrate S to form a thin film. The evaporation source is a known technique, so it will be briefly described here. For example, the evaporation source may be composed of a container (crucible) for storing the film-forming material, a heater for heating the container, a shutter for stopping the release of the film-forming material, a driving mechanism for driving various components such as the shutter, and an evaporation rate monitor for determining the thickness of the film being formed.

[0017] The film formation range by the film formation unit 100 according to this embodiment is the range indicated by R in FIG. 1 . As such, the film formation range R by the film formation unit 100 is limited. Therefore, the film formation unit 100 is configured to be movable along rails 20 provided in the chamber 10, thereby enabling film formation over a wide area. Various known technologies, such as a ball screw mechanism or a rack-and-pinion mechanism, can be employed as a mechanism for moving the film formation unit 100. Note that, depending on the size of the substrate S, it is possible to integrally configure the film formation source 110 and the like, thereby eliminating the need to provide a movable film formation unit 100, and instead employ a configuration in which the film formation source and the like are fixed to the chamber 10.

[0018] The mask M has openings at positions corresponding to positions where a thin film is to be formed on the substrate S, and is configured to cover positions on the substrate S where a thin film is not to be formed. As a result, by forming a film on the substrate S through the mask M, a thin film of a desired pattern (a pattern corresponding to the positions where the openings are formed) is formed on the substrate S. The film forming apparatus 1 is provided with a mechanism for adjusting the relative positions of the substrate S and the mask M, but since publicly known technology can be applied to this mechanism, a description thereof will be omitted here. Generally, film formation is performed with the substrate and the mask in close contact with each other.

[0019] The film forming apparatus 1 also has a control unit C. The control unit C has functions to control various devices, such as controlling the film forming source 110 and controlling the alignment (relative position adjustment) between the substrate S and the mask M. The control unit C can be configured, for example, by a computer having a processor, memory, storage, I / O, etc. In this case, the functions of the control unit C are realized by the processor executing a program stored in the memory or storage. As the computer, a general-purpose personal computer may be used, or an embedded computer or a PLC (programmable logic controller) may be used. Alternatively, some or all of the functions of the control unit C may be configured by a circuit such as an ASIC or FPGA.

[0020] In this embodiment, as described above, the limiting member 120 is provided. This limiting member 120 is configured as a box-shaped member with an opening 121 formed only in the ceiling surface. As a result, only components of the deposition particles, which are the film formation material emitted from the film formation source 110, that are incident approximately perpendicularly on the substrate S or the mask M are selected and reach and deposit on the substrate S or the mask M. Radiant heat from the film formation source 110 also reaches the film formation range R along with the deposition particles, causing the temperatures of the mask M and the substrate S to rise in this film formation range R. In particular, in recent years, masks M have become increasingly finer and thinner, and their heat capacity has become smaller than that of the substrate S, resulting in a significant temperature rise in the mask M. The typical temperature of the evaporation source serving as the film formation source 110 is around 400°C when evaporating an organic material and may exceed 1000°C when evaporating a metal material. The mask M and the substrate S are heated by radiant heat transfer from the evaporation source. The temperatures of the mask M and the substrate S at this time vary depending on the apparatus configuration and the surface conditions (emissivity, etc.) of the components constituting the apparatus. For example, if the distance from the evaporation source to the substrate S is assumed to be about 1000 mm, the temperature of the mask M may rise by at least several degrees Celsius to several tens of degrees Celsius, and in some cases even more. Furthermore, the heat capacities of the mask M and the substrate S are different. A thin-film mask M generally has a small heat capacity. When exposed to radiant energy, the mask M generally heats up in a few to several tens of seconds, whereas the temperature rise rate of the substrate S is often an order of magnitude slower than that of the mask M. This results in relative thermal displacement between the mask M and the substrate S during deposition, degrading the deposition quality. For example, if the mask and substrate are 500 mm x 500 mm in size, and the temperature difference between the mask M and the substrate S is 2 degrees Celsius and the linear expansion coefficient is 2 x 10 －６ °C －１ Assuming that the relative thermal displacement between the mask and the substrate is 500 mm x 2 °C x 2 x 10 －６ °C －１ = 2 μm. This is a size that cannot be ignored in the deposition of devices that require high definition, such as VRHMD. Furthermore, as the mask M becomes thinner, the thermal resistance in the mask plane direction increases, making it difficult to dissipate heat by thermal conduction. Therefore, the film forming apparatus 1 according to this embodiment is provided with a radiant cooling member 130.

[0021] <Radiation Cooling Member> The radiation cooling member 130 will be described in detail. The radiation cooling member 130 is provided at a position that does not obstruct the path of the film formation material from the film formation source 110 to the film formation region R on the substrate S. More specifically, an opening 131a that serves as the path of the film formation material is provided in the center of the radiation cooling member 130. As a result, the radiation cooling member 130 is provided at a position that does not obstruct the path of the film formation material from the film formation source 110 to the film formation region R on the substrate S. The radiation cooling member 130 also has a cooling surface 131 that is capable of heat exchange by radiation. The cooling surface 131 is disposed so that the normal to its surface intersects with the center (near the center) of the film formation region R. In this embodiment, the cooling surface 131 is formed of a hemispherical surface, and is disposed so that the center of the hemisphere is located at the center of the film formation region R. As a result, the normal to the surface of the cooling surface 131 intersects with the center of the film formation region R.

[0022] The radiation cooling member 130 is also provided with piping 132 through which a refrigerant for temperature control circulates. In this embodiment, a configuration is adopted in which the temperature of the radiation cooling member 130 is controlled by circulating the refrigerant through the piping 132. That is, the temperature of the radiation cooling member 130 can be controlled by changing the temperature of the refrigerant, changing the flow rate of the refrigerant, or a combination of these. In a film formation apparatus, cooling piping using a refrigerant such as water is generally installed near the film formation source. Branching a portion of this piping and leading it to the radiation cooling member 130, as in this embodiment, can provide a simple structure. Of course, a dedicated cooling piping system may also be configured, which is preferable for achieving more accurate temperature control. The configuration for controlling the temperature of the radiation cooling member 130 is not limited to a configuration using a refrigerant. For example, a configuration in which a Peltier element (not shown) for temperature control is provided in the radiation cooling member 130 may also be adopted.

[0023] As described above, the film formation area R is an area that is heated and heated by radiant heat from the film formation source 110. Now, if the temperature of the film formation area R is T1 (K), the surface temperature of the cooling surface 131 is T2 (K), and T1>T2, the energy flux J (W / m ２ ) is the Stefan-Boltzmann constant 5.67 × 10 －８ W / m ２ K ４ Then, J = σ × (T1 ４ -T2 ４ ) ...Equation 1. Here, for simplicity, the emissivity is set to 1 and the view factor is ignored. By controlling the temperature of the radiant cooling member 130, generating an energy flow determined by Equation 1, and removing energy in the form of radiation from the film formation area R, it is possible to lower the temperature of the film formation area R. Radiant heat energy from the film formation source 110 flows into the film formation area R, causing the temperature of the film formation area R to rise, and thermal radiation energy flows out from the film formation area R to the radiant cooling member 130. The temperature of the film formation area R is determined by the balance between this inflow and outflow.

[0024] In order to effectively cool the film formation area R, as described above, the cooling surface 131 is configured so that the normal to the surface intersects with the center of the film formation area R. In particular, as in this embodiment, it is desirable that the cooling surface 131 be configured as a hemispherical surface, with the center of the hemisphere located at the center of the film formation area R. The reason for this is explained below. The thermal energy emitted from the film formation area R according to Equation 1 spreads isotropically from the film formation area R. If the cooling surface 131 is configured as a hemispherical surface, the thermal energy can be received without leakage. Furthermore, since the radiant electromagnetic waves emitted from the film formation area R (see the solid arrows in FIG. 3 ) are perpendicularly incident on the surface of the cooling surface 131, even if there are reflected components of the electromagnetic waves (see the dotted arrows in FIG. 3 ), the reflected components return to the emission point in the film formation area R. Therefore, the thermal energy is not diffused in the mask plane due to multiple reflections, enabling efficient cooling.

[0025] Next, the film of film-forming material formed on the cooling surface 131 will be described with reference to Fig. 4. Even if the radiation cooling member 130 is provided at a position that does not obstruct the path of the film-forming material from the film-forming source 110 to the film-forming area R on the substrate S, as in this embodiment, a film will still be formed on the cooling surface 131. This point will be described below.

[0026] In a general vacuum deposition device or deposition process for organic EL, the pressure in the chamber during film formation (deposition) is 10 －２ In this case, the mean free path λ (m) of the film-forming material particles (evaporation particles) is given by: λ = (k × T) / ((√2) × π × p × d ２ )

[0027] Here, k = 1.38 × 10 －２３ (J / K) is the Boltzmann constant, T is the gas temperature (K), p is the gas pressure (Pa), and d is the gas molecular diameter (m ２ ) The mean free path means the average distance that a gas molecule can fly in a straight line without colliding with other gas molecules. For example, if the pressure is 10 －２ Pa, gas molecule diameter 3.5 x 10 －１０ m ２ If the gas temperature is 300 K, λ is approximately 0.76 m = 760 mm, which is on the same order as the distance from the film formation source 110 to the mask M or the substrate S. Therefore, as shown by the solid arrow in Figure 4, the deposition particles emitted from the film formation source 110 are not scattered even once on average, but reach the mask M or the substrate S in a straight line. However, as shown by the dotted arrow in Figure 4, some particles are scattered along the way and their trajectories change, and some of the scattered particles reach the cooling surface 131, which is located in a shaded area (an area that cannot be seen) from the film formation source 110.

[0028] Although the number of scattering particles that reach the cooling surface 131 in one deposition is small, when deposition is performed continuously over a long period of time, such as during mass production, the cumulative amount of scattering particles deposited on the cooling surface 131 becomes large enough to be ignored. The specific amount of particles that reach the cooling surface 131 is difficult to calculate because it varies greatly depending on the configuration of the apparatus, the pressure during deposition, and the like, but it is typically expected to be about 0.1% to several percent of the amount of particles that reach the mask M or substrate S.

[0029] When a film made of a film-forming material is formed on the cooling surface 131, its cooling capacity changes due to the film's own absorption of electromagnetic waves, surface roughness, changes in emissivity, and other factors. For example, Alq3, an organic material widely used in organic electroluminescence (EL) deposition, is known to absorb electromagnetic waves in the near-infrared region by several percent at a thickness of several tens of nanometers. This amount is sufficient to change the cooling capacity and cannot be ignored in mass-production equipment designed for continuous operation. Furthermore, the amount of film deposited on the cooling surface 131 (film thickness) does not necessarily increase steadily over time due to fluctuations in production volume during continuous operation and bumping. Therefore, in this embodiment, a film thickness meter 140 located near the radiant cooling element 130 is used to measure the thickness of the film formed on the cooling surface 131, and the controller C controls the temperature of the radiant cooling element 130 to compensate for changes in cooling capacity. That is, in the film-forming apparatus 1 according to this embodiment, the temperature of the radiant cooling element 130 is controlled according to the thickness of the film made of the film-forming material formed on the cooling surface 131. In this embodiment, the film thickness meter 140 is provided so that the tip of the film thickness meter 140 slightly protrudes from the opening 131 b formed in the cooling surface 131 .

[0030] A quartz crystal film thickness gauge, which is often used to control the rate of evaporation sources in general vacuum deposition apparatuses including organic EL deposition apparatuses, is suitable for use as the film thickness gauge 140 because it can accurately detect film thicknesses on the order of nm and has a small detection unit. However, if it is difficult to arrange a quartz crystal film thickness gauge due to design constraints or the like, it is also possible to adopt control in which the thickness of the film formed on the cooling surface 131 is proportional to the deposition time or the apparatus operating time, and the temperature of the radiant cooling member 130 is corrected as a function of time. In this way, it is also possible to adopt a configuration in which the thickness of the film made of the film formation material formed on the cooling surface 131 is derived using parameters including the measured film formation time.

[0031] The relationship between the thickness of the film formed on the cooling surface 131 (the amount of film deposition) and the change in the cooling capacity of the radiant cooling member 130 is thought to vary significantly depending on the deposition material and the device configuration. Therefore, it is practical to confirm this relationship in advance through elemental experiments and store the relationship as a table. That is, the controlled temperature of the radiant cooling member 130 when no film is formed on the cooling surface 131 is used as the reference temperature, and the temperature reduction amount corresponding to the thickness of the film formed on the cooling surface 131 by the film material should be set to be proportional to the X power of the film thickness. X is set depending on the film material and film formation conditions. Typically, X is set to one-fourth. This is because, assuming that electromagnetic wave absorption increases linearly in proportion to the film thickness in an organic film such as Alq3, a correction can be made to reduce the temperature of the cooling surface 131 of the radiant cooling member 130 in proportion to the ¼ power of the film thickness, according to the Stefan-Boltzmann law of the fourth power of temperature for radiant energy. This proportionality coefficient may be identified in advance through an experiment.

[0032] As described above, the film formation method using the film formation apparatus 1 according to this embodiment includes a step of acquiring the thickness of the film made of the film formation material formed on the cooling surface 131 by the control unit C, and a step of controlling the temperature of the radiation cooling member 130 in accordance with the acquired film thickness. This allows the cooling function to be maintained even if the thickness of the film formed on the cooling surface 131 increases over time, and the mask M to be cooled stably. Therefore, high film formation accuracy can be maintained.

[0033] Although only one film thickness meter 140 is provided in this embodiment, a configuration in which multiple units are provided can also be adopted. In this case, the thickness of the film formed by the film-forming material at multiple locations on the cooling surface 131 is measured. This allows the temperature of the radiation cooling member 130 to be controlled individually at multiple locations, thereby maintaining a more stable cooling function. It is also possible to control the temperature by determining the amount of temperature correction based on the average film thickness at each location, etc.

[0034] Furthermore, when employing a configuration in which film formation is performed over the entire substrate S while the film formation unit 100 is moved, as in this embodiment, the temperature control amount of the radiant cooling member 130 may be controlled to change in accordance with the movement of the film formation range R. For example, control may be performed to change the temperature correction amount when film formation is performed in the central portion of the substrate S or mask M and when film formation is performed in the edge portion. This is because, for example, the amount of heat escaping through the members supporting the substrate S or mask M differs depending on their positions, and therefore the appropriate correction amount when changing the temperature of the radiant cooling member 130 may change.

[0035] (Example 2) Figure 5 shows Example 2 of the present invention. Example 1 described above showed a configuration in which a single radiant cooling element whose cooling surface is formed by a hemispherical surface is provided. In contrast, this example shows a configuration in which multiple radiant cooling elements are provided. The other configurations and functions are the same as in Example 1, so the same components are given the same reference numerals and their description will be omitted.

[0036] Second Embodiment Fig. 5 is a schematic diagram of a film formation apparatus according to a second embodiment of the present invention. Fig. 5 shows a schematic diagram of the internal configuration of the apparatus, with a portion of the configuration shown in a schematic cross-sectional view. The film formation apparatus 1A according to this embodiment also includes a chamber 10 and a film formation unit 100A. The film formation unit 100A includes a film formation source 110, a limiting member 120, a radiation cooling member 130A, and a film thickness meter 140.

[0037] This embodiment differs from the first embodiment in that a plurality of radiant cooling members 130A are provided. As in the first embodiment, each radiant cooling member 130A is provided with a cooling surface 131A and a pipe 132A through which a refrigerant for temperature control circulates. The plurality of radiant cooling members 130A are arranged so that the normal to each cooling surface 131A intersects the center (near the center) of the film formation area R. The shape of the cooling surface 131A may be flat or may be a concave curved surface. In other words, as described above, the shape of the surface is not limited as long as the normal to the cooling surface 131A intersects the center of the film formation area R. By setting the inclination angle and surface shape of the cooling surface 131A according to the position of the radiant cooling member 130A, it is possible to make the normal to the cooling surface 131A intersect the center of the film formation area R. By adopting the configuration of this embodiment, the height of the radiation cooling member 130A can be reduced compared to Example 1, thereby increasing the degree of freedom in design. This is particularly effective when the height of the radiation cooling member 130A is limited by design constraints.

[0038] In this embodiment, a refrigerant is used to control the temperature of the radiation cooling member 130A. However, as described in Example 1, the temperature control configuration is not limited to this. For example, a Peltier element can also be used. Also in this embodiment, the thickness of the film formed on the cooling surface 131A can be detected using a film thickness meter 140 such as a quartz crystal film thickness meter. However, as described in Example 1, a configuration can also be adopted in which the thickness of the film formed on the cooling surface 131A is calculated using parameters including the measured film formation time. Also in this embodiment, by using a configuration in which multiple film thickness meters 140 are arranged, the temperature of the radiation cooling member 130A can be individually controlled at multiple locations, and the temperature correction amount can be determined based on the average film thickness for each location. Furthermore, in this embodiment, when a configuration in which film formation is performed over the entire substrate S while the film formation unit 100A is moved is adopted, the temperature control amount of the radiation cooling member 130A can be controlled to change according to the movement of the film formation range R.

[0039] <Method for Manufacturing Electronic Device> An example of a method for manufacturing an electronic device using the film formation apparatus 1, 1A according to each of the above embodiments will be described. Below, the configuration and manufacturing method of an organic EL display device will be illustrated as an example of an electronic device. First, the organic EL display device to be manufactured will be described. Fig. 6(a) is an overall view of an organic EL display device 560, and Fig. 6(b) shows the cross-sectional structure of one pixel.

[0040] As shown in FIG. 6A , a display area 561 of an organic EL display device 560 includes a matrix of pixels 562, each including a plurality of light-emitting elements. As will be described in detail later, each light-emitting element has a structure including an organic layer sandwiched between a pair of electrodes. Note that the term "pixel" as used herein refers to the smallest unit capable of displaying a desired color in the display area 561. In the organic EL display device according to this embodiment, each pixel 562 is configured by a combination of a first light-emitting element 562R, a second light-emitting element 562G, and a third light-emitting element 562B, which emit light different from one another. While the pixel 562 is often configured by a combination of red, green, and blue light-emitting elements, it may also be configured by a combination of yellow, cyan, and white light-emitting elements, and is not particularly limited as long as it emits at least one color.

[0041] 6(b) is a partial cross-sectional schematic diagram taken along line A-B in FIG. 6(a). A pixel 562 includes an organic EL element on a substrate 563, the organic EL element including a first electrode (anode) 564, a hole transport layer 565, one of light-emitting layers 566R, 566G, and 566B, an electron transport layer 567, and a second electrode (cathode) 568. Of these, the hole transport layer 565, the light-emitting layers 566R, 566G, and 566B, and the electron transport layer 567 correspond to organic layers. In this embodiment, the light-emitting layer 566R is an organic EL layer that emits red light, the light-emitting layer 566G is an organic EL layer that emits green light, and the light-emitting layer 566B is an organic EL layer that emits blue light. The light-emitting layers 566R, 566G, and 566B are formed in patterns corresponding to light-emitting elements (sometimes referred to as organic EL elements) that emit red, green, and blue light, respectively. Furthermore, the first electrode 564 is formed separately for each light-emitting element. The hole transport layer 565, the electron transport layer 567, and the second electrode 568 may be formed in common with the plurality of light-emitting elements 562R, 562G, and 562B, or may be formed for each light-emitting element. Note that an insulating layer 569 is provided between the first electrodes 564 to prevent short-circuiting between the first electrode 564 and the second electrode 568 due to foreign matter. Furthermore, because the organic EL layer deteriorates due to moisture and oxygen, a protective layer 570 is provided to protect the organic EL element from moisture and oxygen.

[0042] 6(b), the hole transport layer 565 and the electron transport layer 567 are shown as a single layer, but they may be formed of multiple layers including a hole blocking layer and an electron blocking layer depending on the structure of the organic EL display element. Furthermore, a hole injection layer having an energy band structure that can smoothly inject holes from the first electrode 564 to the hole transport layer 565 can be formed between the first electrode 564 and the hole transport layer 565. Similarly, an electron injection layer can be formed between the second electrode 568 and the electron transport layer 567.

[0043] Next, an example of a method for manufacturing an organic EL display device will be specifically described. First, a circuit (not shown) for driving the organic EL display device and a substrate 563 on which a first electrode 564 is formed are prepared.

[0044] An acrylic resin is formed by spin coating on the substrate 563 on which the first electrode 564 is formed, and the acrylic resin is patterned by lithography so as to form an opening in the portion where the first electrode 564 is formed, thereby forming an insulating layer 569. This opening corresponds to the light-emitting region where the light-emitting element actually emits light.

[0045] The substrate 563 with the patterned insulating layer 569 is carried into a first film forming apparatus, and the substrate is held by a substrate support unit. A hole transport layer 565 is formed as a common layer on the first electrode 564 in the display region. The hole transport layer 565 is formed by vacuum deposition. In practice, the hole transport layer 565 is formed to be larger than the display region 561, so a high-resolution mask is not required.

[0046] Next, the substrate 563 on which the hole transport layer 565 has been formed is carried into a second film formation apparatus and held by a substrate support unit. The substrate and a mask are aligned (first alignment and second alignment), the substrate is placed on the mask, and a red light-emitting layer 566R is formed on the portion of the substrate 563 where the red light-emitting element is to be disposed.

[0047] Similar to the formation of the light-emitting layer 566R, a green-emitting light-emitting layer 566G is formed by a third film formation apparatus, and then a blue-emitting light-emitting layer 566B is formed by a fourth film formation apparatus. After the formation of the light-emitting layers 566R, 566G, and 566B is completed, an electron transport layer 567 is formed over the entire display region 561 by a fifth film formation apparatus. The electron transport layer 567 is formed as a layer common to the three-color light-emitting layers 566R, 566G, and 566B.

[0048] The substrate on which the electron transport layer 567 has been formed is transferred to a sputtering device, where a second electrode 568 is formed, and then transferred to a plasma CVD device, where a protective layer 570 is formed, thereby completing the organic EL display device 560 .

[0049] If the substrate 563 on which the insulating layer 569 has been patterned is exposed to an atmosphere containing moisture or oxygen from the time it is carried into the film-forming apparatus until the completion of the formation of the protective layer 570, the light-emitting layer made of an organic EL material may be deteriorated by the moisture or oxygen. Therefore, in this example, the substrate is carried in and out of the film-forming apparatus in a vacuum atmosphere or an inert gas atmosphere.

[0050] 1, 1A: Film forming apparatus 10: Chamber 20: Rail 100, 100A: Film forming unit 110: Film forming source 120: Restricting member 121: Opening 130, 130A: Radiation cooling member 131, 131A: Cooling surface 131a: Opening 132, 132A: Piping 140: Film thickness meter C: Control unit M: Mask R: Film forming range S: Substrate

Claims

1. A film forming apparatus for forming a thin film on a substrate through a mask by a film forming material emitted from a film forming source in a chamber, comprising a radiation cooling member provided at a position that does not obstruct the path of the film forming material from the film forming source to the film forming range of the substrate and having a cooling surface capable of heat exchange by radiation, wherein the temperature of the radiation cooling member is controlled according to the thickness of the film formed by the film forming material on the cooling surface.

2. The film forming apparatus according to claim 1, wherein the cooling surface is arranged such that the normal of its surface intersects the center of the film forming range.

3. The film forming apparatus according to claim 2, wherein the cooling surface is constituted by a hemispherical surface, and the center of the hemispherical surface is arranged to be located at the center of the film forming range.

4. The film forming apparatus according to claim 2, wherein a plurality of the radiation cooling members are provided, and the plurality of radiation cooling members are arranged such that the normal of the surface of each cooling surface intersects the center of the film forming range.

5. The film forming apparatus according to claim 1, wherein a pipe through which a refrigerant for controlling the temperature circulates is provided in the radiation cooling member.

6. The film forming apparatus according to claim 1, wherein a Peltier element for controlling the temperature is provided in the radiation cooling member.

7. The film forming apparatus according to claim 1, further comprising a crystal film thickness meter for measuring the thickness of the film formed by the film forming material on the cooling surface.

8. The film forming apparatus according to claim 1, wherein the thickness of the film formed by the film forming material on the cooling surface is derived using a parameter including the measured film forming time.

9. The film forming apparatus according to claim 1, wherein, taking the control temperature of the radiation cooling member in a state where no film is formed on the cooling surface as a reference temperature, the temperature decrease amount that decreases according to the thickness of the film formed by the film forming material on the cooling surface is set to be proportional to the X-th power of the thickness of the film.

10. The film forming apparatus according to claim 9, wherein X is set according to the film forming material and the film forming conditions.

11. The film forming apparatus according to claim 1, wherein the temperature of the radiation cooling member is individually controlled at the plurality of locations according to the thickness of the film formed by the film forming material formed at each of the plurality of locations on the cooling surface.

12. The film forming apparatus according to claim 1, wherein a temperature control amount of the radiative cooling member changes according to movement of the film forming range.

13. A film forming method for forming a thin film on a substrate through a mask by a film forming material discharged from a film forming source in a chamber, the method comprising: providing a radiative cooling member having a cooling surface capable of heat exchange by radiation at a position that does not obstruct a path of the film forming material from the film forming source to a film forming range of the substrate; obtaining a thickness of a film formed by the film forming material formed on the cooling surface; and controlling a temperature of the radiative cooling member according to the obtained thickness of the film.

14. A method for manufacturing an electronic device, characterized by manufacturing the electronic device using the film forming method according to claim 13.

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