Film deposition apparatus, method for depositing film, and method for manufacturing electronic device

Abstract

To provide a film deposition apparatus that can cool a mask stably, and to provide a method for depositing a film and a method for manufacturing an electronic device.SOLUTION: A film deposition apparatus 1 for forming a thin film on a substrate S via a mask M with a film deposition material that is discharged from a film deposition source 110 within a chamber 10 includes a radiation cooling member 130 installed in a position of not avoiding a route of a film deposition material which reaches a film deposition range R of the substrate S from the film deposition source 110 and including a cooling surface 131 capable of exchanging heat by radiation, where the temperature of the radiation cooling member 130 is controlled in accordance with a thickness of a film that is made of the film deposition material and formed on the cooling surface 131.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Organic EL display devices (organic EL displays) are widely used not only in smartphones, televisions, and automotive displays, but also in applications such as VR HMDs (Virtual Reality Head-Mounted Displays). In particular, displays used in VR HMDs are required to form pixel patterns with high precision, such as reducing user dizziness, and further higher resolution is demanded.

[0003] In the manufacture of an organic EL display device, when forming an organic light emitting element (organic EL element; OLED) that constitutes the organic EL display device, a film forming material emitted from a film forming source is deposited on a substrate through a mask on which a pixel pattern is formed, thereby forming an organic layer or a metal layer.

[0004] In such a film forming method, while the film forming material is emitted from the film forming source, the energy of thermal radiation is also emitted. Due to the thermal radiation from the film forming source, in particular, the mask is heated up and thermally expanded, and the relative position between the mask and the substrate changes. If the relative position between the mask and the substrate changes during film formation, it becomes impossible to form the pixel pattern with high precision. Therefore, in particular, cooling of the mask is necessary.

[0005] Generally, when cooling an object, three heat transfer modes, namely, heat conduction, convection, and radiation, can be utilized. However, in the above film-forming method, since film formation is performed in a vacuum chamber, convection cannot be utilized, and it is necessary to perform heat transfer by either heat conduction or radiation. Among these, regarding heat conduction, due to factors such as the tendency for the in-plane thermal resistance to increase with the thinning of the mask as the pixel pattern becomes more highly refined, and the difficulty in managing the contact state with the substrate resulting in variations in the contact thermal resistance, it is difficult to actively utilize heat conduction. Therefore, in the cooling of the mask during the above film-forming process, it is considered desirable to utilize radiation.

[0006] When radiatively cooling the mask, it is effective to dispose, relative to the heated portion of the mask, a radiative cooling member having a surface capable of maintaining a lower temperature than the heated portion of the mask in the vicinity thereof. For example, Patent Document 1 discloses a technique related to a radiative cooling member that hemispherically covers the heated portion of the mask. However, the technique disclosed in Patent Document 1 is directed to an EB exposure apparatus, and it is not assumed that a film will be formed on the surface of the radiative cooling member due to scattering of the particles of the film-forming material emitted from the film-forming source. In such an operating environment where such a film is formed, there are problems such as the need for periodic cleaning and the change in the cooling capacity as the film thickness increases.

[0007] Further, Patent Document 2 discloses a technique of disposing a radiative cooling member on the back side of a deposition-preventing plate that covers the entire interior of the chamber. In this technique, in a film-forming apparatus, in order to prevent the formation of a film on the surface of the radiative cooling member due to scattering of the film-forming material emitted from the film-forming source, the radiative cooling member is disposed on the back side of the deposition-preventing plate. In this case, since the mask is cooled through the deposition-preventing plate, it is difficult to fully exhibit the cooling function of the radiative cooling member, and there are problems such as the change in the cooling capacity as the film thickness formed on the surface of the deposition-preventing plate increases.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

[0009] As described above, in the film forming apparatus, even if a radiation cooling member is provided, due to the adhesion of the film forming material, it is impossible to stably cool the mask, and it has been difficult to improve the film forming accuracy.

[0010] An object of the present invention is to provide a film forming apparatus, a film forming method, and a method for manufacturing an electronic device capable of stably cooling a mask. [Means for Solving the Problems]

[0011] The film forming apparatus of the present invention is a film forming apparatus for forming a thin film on a substrate through a mask by a film forming material released 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, characterized in that the temperature of the radiation cooling member is controlled according to the thickness of the film formed by the film forming material formed on the cooling surface. [Effects of the Invention]

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

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0014] Hereinafter, with reference to the drawings, embodiments for carrying out the present invention will be exemplarily and specifically described based on examples. However, dimensions, materials, shapes, relative arrangements, etc. of the components described in this example are not intended to limit the scope of the present invention only to these unless specifically described otherwise.

[0015] (Example 1) With reference to FIGS. 1 to 4, a film forming apparatus, a film forming method, and a method for manufacturing an electronic device according to Example 1 of the present invention will be described. FIG. 1 is a schematic configuration diagram of the film forming apparatus according to Example 1 of the present invention. In FIG. 1, the configuration inside the apparatus is schematically shown, and some configurations are shown by schematic cross-sectional views. FIG. 2 is a plan view of the radiative cooling member according to Example 1 of the present invention. The cross-sectional view of the radiative cooling member in FIG. 1 corresponds to the AA cross-sectional view in FIG. 2. FIGS. 3 and 4 are schematic cross-sectional views of the radiative cooling member or the like according to Example 1 of the present invention. FIG. 3 is an explanatory diagram of heat exchange during film formation, and FIG. 4 is a diagram showing the state of particles which are the film forming 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 inside of the chamber 10 is configured to be maintained in 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 and a limiting member 120 that restricts the irradiation direction of the film-forming material, a radiative cooling member 130, and a film thickness gauge 140. The film-forming apparatus 1 according to this embodiment is a vacuum evaporation 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 and is deposited (evaporated) on the substrate S through the opening of the mask M to form a thin film. Since the evaporation source is a known technique, it will be briefly described here. For example, the evaporation source includes a container (crucible) for containing the film-forming material, a heater for heating the container, a shutter for stopping the release of the film-forming material, a drive mechanism for driving various members such as the shutter, and an evaporation rate monitor for recognizing the thickness of the film to be formed.

[0017] The film-forming range by the film-forming unit 100 according to this embodiment is the range indicated by R in FIG. 1. Thus, the film-forming range R by the film-forming unit 100 is limited. Therefore, the film-forming unit 100 is configured to be movable along the rail 20 provided in the chamber 10 so that film formation over a wide range can be achieved. For the mechanism for moving the film-forming unit 100, various known techniques such as a ball screw mechanism and a rack and pinion mechanism can be adopted. Note that depending on the size of the substrate S, it is not necessary to provide a movable film-forming unit 100 by integrally configuring the film-forming source 110 and the like, and a configuration in which the film-forming source and the like are fixed to the chamber 10 can also be adopted.

[0018] The mask M is provided with an opening at a position corresponding to the position where the thin film is to be formed on the substrate S, and is configured to cover the positions on the substrate S where the thin film is not formed. Thereby, by performing film formation on the substrate S through the mask M, a thin film having a desired pattern (a pattern corresponding to the position where the opening is provided) is formed on the substrate S. In the film-forming apparatus 1, a mechanism for adjusting the relative position between the substrate S and the mask M is provided. Since a known technique can be applied to this mechanism, the description thereof is omitted here. Generally, when film formation is performed, it is performed with the substrate and the mask in close contact.

[0019] In addition, the film forming apparatus 1 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 by, for example, a computer having a processor, a memory, a 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 the 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, part or all of the functions of the control unit C may be configured by a circuit such as an ASIC or an FPGA.

[0020] In this embodiment, as described above, the restricting member 120 is provided. This restricting member 120 is composed of a box-shaped member having an opening 121 formed only on the ceiling surface. Thereby, only the components of the vapor deposition particles, which are the film forming materials released from the film forming source 110, that are incident substantially vertically with respect to the substrate S and the mask M are selected and reach and deposit on the substrate S and the mask M. Since the radiant heat from the film forming source 110 also reaches the film forming range R at the same time as the vapor deposition particles, the temperature of the mask M and the substrate S rises in this film forming range R. In particular, in recent years, the high definition and thin film formation of the mask M have progressed, and since the heat capacity of the mask M is smaller than that of the substrate S, the temperature rise of the mask M has become remarkable. A typical temperature of the evaporation source as the film forming source 110 is around 400°C when depositing an organic material, and may exceed 1000°C when depositing a metal material. The mask M and the substrate S are heated by the radiant heat transfer from this evaporation source. The temperature of the mask M and the substrate S at this time varies depending on the device configuration and the surface state (emissivity, etc.) of the members constituting the device. For example, assuming that the distance from the evaporation source to the substrate S is about 1000 mm, the temperature of the mask M can rise by at least several degrees Celsius to a dozen or more degrees Celsius, and in some cases even more. Also, the heat capacities of the mask M and the substrate S are different, and generally, the mask with a thinner film Mask M has a small heat capacity. When receiving radiant energy, mask M generally heats up in about several seconds to about ten-odd seconds, while the heating rate of substrate S is often one order of magnitude or more slower than that of mask M. For this reason, a relative thermal displacement occurs between mask M and substrate S during vapor deposition, resulting in a deterioration of the vapor deposition quality. For example, assuming the sizes of the mask and the substrate are 500 mm × 500 mm, the temperature difference between mask M and substrate S is 2 °C, and the linear expansion coefficient is 2 × 10 -6 °C -1 , then the relative thermal displacement amount between the mask and the substrate is 500 mm × 2 °C × 2 × 10 -6 °C -1 = 2 μm. This is a size that cannot be ignored in the vapor deposition of devices that require high definition such as VRHMD. Furthermore, with the thinning of mask M, the thermal resistance in the in-plane direction of the mask increases, making it difficult to release heat by heat conduction. Therefore, in the film-forming apparatus 1 according to the present embodiment, a radiation cooling member 130 is provided.

[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-forming material from the film-forming source 110 to the film-forming range R of the substrate S. More specifically, an opening 131a serving as the path of the film-forming material is provided at the center of the radiation cooling member 130. Thereby, 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 range R of the substrate S. Further, the radiation cooling member 130 has a cooling surface 131 capable of heat exchange by radiation. This cooling surface 131 is arranged such that the normal line of its surface intersects the center (near the center) of the film-forming range R. In the present embodiment, the cooling surface 131 is formed by a hemispherical surface and is arranged such that the center of the hemispherical surface is located at the center of the film-forming range R. Thereby, the normal line of the surface of the cooling surface 131 is configured to intersect the center of the film-forming range R.

[0022] In addition, a pipe 132 through which a refrigerant for controlling the temperature circulates is provided in the radiative cooling member 130. In this embodiment, a configuration is adopted in which the temperature of the radiative cooling member 130 is controlled by circulating the refrigerant through the pipe 132. That is, the temperature of the radiative cooling member 130 can be controlled by changing the temperature of the refrigerant, changing the flow rate of the refrigerant, or combining these. In a film forming apparatus, it is common to have cooling pipes using a refrigerant such as water stretched around the vicinity of the film forming source. By branching a part of this pipe and leading it into the radiative cooling member 130 as in this embodiment, a simple structure can be achieved. Of course, a dedicated cooling pipe system may be configured, and this is preferable for realizing more accurate temperature control. Note that the configuration for controlling the temperature of the radiative cooling member 130 is not limited to a configuration using a refrigerant. For example, a configuration can also be adopted in which a Peltier element (not shown) for controlling the temperature is provided in the radiative cooling member 130.

[0023] As described above, the film forming range R is a region that is heated and its temperature rises due to the radiant heat from the film forming source 110. Now, let the temperature of the film forming range R be T1 (K) and the surface temperature of the cooling surface 131 be T2 (K), and assume T1 > T2. Then, the energy flux J (W / m 2 ) transmitted from the film forming range R to the cooling surface 131 is, with σ being the Stefan-Boltzmann constant of 5.67×10 -8 W / m 2 K 4 defined as J = σ×(T1 4 - T2 4 ) ··· Equation 1 where, for simplicity, the emissivity is 1 and the shape factor is ignored. By controlling the temperature of the radiative cooling member 130, generating the energy flow defined by Equation 1, and depriving the film forming range R of energy in the form of radiation, it becomes possible to lower the temperature of the film forming range R. Radiant heat energy from the film forming source 110 flows into the film forming range R, thereby increasing the temperature of the film forming range R, and thermal radiation energy flows out from the film forming range R to the radiative cooling member 130. Due to the balance of this inflow and outflow, the temperature of the film forming range R is determined.

[0024] In order to effectively cool the film formation range R, as described above, a configuration is adopted in which the normal line of the surface of the cooling surface 131 intersects the center of the film formation range R. In particular, as in this embodiment, it is desirable that the cooling surface 131 is configured by a hemispherical surface and the center of the hemispherical surface is located at the center of the film formation range R. The reason for this will be explained. The thermal energy released from the film formation range R according to Equation 1 spreads isotropically from the film formation range R. If the cooling surface 131 is configured by a hemispherical surface, the thermal energy can be received without leakage. Further, since the electromagnetic wave of the radiation emitted from the film formation range R (see the solid line arrow in FIG. 3) is incident perpendicularly to the surface of the cooling surface 131, even if there is a reflection component of the electromagnetic wave (see the dotted line arrow in FIG. 3), the reflection component will return to the emission location of the film formation range R. Therefore, the in-plane diffusion of thermal energy due to multiple reflections does not occur, and efficient cooling becomes possible. Next, the film of the film forming material formed on the cooling surface 131 will be described with reference to FIG. 4. Even if the radiative 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 formation range R on the substrate S as in this embodiment, a film will be formed on the cooling surface 131. This point will be explained below.

[0025] In general vacuum deposition apparatuses or deposition processes such as organic ELs, the pressure in the chamber during film formation (deposition) is generally around 10

[0026] Pa. The mean free path λ (m) of the particles of the film forming material (deposition particles) in this case is -2 λ=(k×T) / ((√2)×π×p×d where 2 ) k = 1.38×10

[0027] (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 -23 ). The mean free path means the average distance that a gas molecule can fly linearly without colliding with other gas molecules. For example, when the pressure is 10 2 Pa, -2Pa. If the gas molecular diameter is 3.5×10 -10 m 2 and the gas temperature is 300 K, then λ is approximately 0.76 m = 760 mm, which is of the same order as the distance from the film-forming source 110 to the mask M and the substrate S. Therefore, as shown by the solid-line arrow in Fig. 4, the vapor deposition particles emitted from the film-forming source 110 generally reach the mask M and the substrate S linearly without being scattered even once. However, as shown by the dotted-line arrow in Fig. 4, probabilistically, some of the particles are scattered on the way and their trajectories change, and some of the scattered particles reach the cooling surface 131 disposed in the shaded (invisible) portion as viewed from the film-forming source 110.

[0028] Although the number of scattered particles reaching the cooling surface 131 in one vapor deposition is small, in the case of continuous vapor deposition over a long period such as during mass production, the film deposition amount of the scattered particles on the cooling surface 131 accumulates and becomes so large that it cannot be ignored. Specifically, it is difficult to calculate the amount of particles reaching the cooling surface 131 because it varies greatly depending on the configuration of the apparatus, the pressure during vapor deposition, etc., but it is typically assumed to be about 0.1% to several percent of the amount of particles reaching the mask M and the substrate S.

[0029] When a film made of a film-forming material is formed on the cooling surface 131, the cooling capacity changes due to the absorption of electromagnetic waves by the film itself, surface roughness, changes in emissivity, etc. For example, Alq3, an organic material widely used in the vapor deposition of organic ELs, is known to absorb electromagnetic waves in the near-infrared region at the order of several percent with a film thickness of several tens of nanometers. This is an amount sufficient to change the cooling capacity and cannot be ignored in a mass production apparatus assuming continuous operation. Also, the film deposition amount (film thickness) formed on the cooling surface 131 does not necessarily increase constantly with respect to the elapsed time due to fluctuations in production volume during continuous operation, nucleate boiling, etc. Therefore, in this embodiment, the thickness of the film formed on the cooling surface 131 is measured by the thickness gauge 140 disposed in the vicinity of the radiative cooling member 130, and the temperature of the radiative cooling member 130 is controlled by the control unit C so as to compensate for the change in the cooling capacity. That is, in the film forming apparatus 1 according to this embodiment, the temperature of the radiative cooling member 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 thickness gauge 140 is provided such that the tip of the thickness gauge 140 protrudes slightly from the opening 131b formed in the cooling surface 131. The thickness gauge 140 is provided so that the tip slightly protrudes.

[0030] A crystal thickness gauge often used for rate control of an evaporation source in a general vacuum evaporation apparatus including an organic EL vapor deposition apparatus can accurately detect a film thickness on the order of nm, and since the size of the detection unit is small, it is suitable to be adopted as the thickness gauge 140. However, when it is difficult to arrange the crystal thickness gauge due to design constraints, etc., it can also be adopted to control the temperature correction of the radiative cooling member 130 as a function of time, assuming that the film thickness formed on the cooling surface 131 is proportional to the deposition time or the apparatus operation time. In this way, it is also possible to adopt a configuration in which the thickness of the film made of the film-forming material formed on the cooling surface 131 is derived using parameters including the measured film formation time.

[0031] The correspondence between the thickness of the film (film deposition amount) formed on the cooling surface 131 and the change in the cooling capacity of the radiative cooling member 130 is considered to vary greatly depending on the material to be vapor-deposited and the apparatus configuration. Therefore, it is practical to confirm this correspondence in advance through element experiments or the like and hold the correspondence as a table. That is, taking the control temperature of the radiative cooling member 130 in the state where no film is formed on the cooling surface 131 as the reference temperature, the temperature decrease amount that is decreased according to the thickness of the film formed by the film-forming material formed on the cooling surface 131 may be set to be proportional to the X-th power of the film thickness. Note that X is set according to the film-forming material and the film-forming conditions. Typically, X may be set to 1 / 4. This is because in the case of an organic film such as Alq3, assuming that the absorption of electromagnetic waves increases linearly in proportion to the film thickness, correction may be performed such that the temperature of the cooling surface 131 of the radiative cooling member 130 decreases in proportion to the 1 / 4-th power of the film thickness according to the Stefan-Boltzmann law of the radiation energy to the fourth power of the temperature. This proportional coefficient may be identified in advance through experiments.

[0032] As described above, in the film-forming method using the film-forming apparatus 1 according to the present embodiment, the control unit C has a step of acquiring the thickness of the film formed by the film-forming material formed on the cooling surface 131, and a step of controlling the temperature of the radiative cooling member 130 according to the acquired film thickness. Thereby, even if the thickness of the film formed on the cooling surface 131 increases over time, the cooling function can be maintained, and the mask M can be stably cooled. Therefore, the film-forming accuracy can also be maintained at a high level.

[0033] In this embodiment, only one film thickness gauge 140 is arranged, but a configuration in which a plurality of film thickness gauges are arranged can also be adopted. In this case, the thicknesses of the films formed by the film-forming materials formed at a plurality of locations on the cooling surface 131 are measured. Therefore, the temperature of the radiative cooling member 130 can be individually controlled at a plurality of locations, and the cooling function can be maintained more stably. Also, control such as determining the temperature correction amount from the average value of the film thicknesses for each location is possible.

[0034] Also, when adopting a configuration in which film formation is performed on the entire substrate S while moving the film formation unit 100 as in this embodiment, it may be controlled such that the temperature control amount of the radiative cooling member 130 changes according to 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 at the central portion of the substrate S or the mask M and when film formation is performed at the end portion. This is because, for example, the amount of heat escaping through the members supporting the substrate S and the mask M may differ depending on these positions, so the appropriate correction amount when changing the temperature of the radiative cooling member 130 can vary.

[0035] (Example 2) FIG. 5 shows Example 2 of the present invention. In the above Example 1, the configuration in the case where a single radiative cooling member having a hemispherical cooling surface is provided was shown. In contrast, in this example, the configuration in the case where a plurality of radiative cooling members are provided is shown. Since the other configurations and operations are the same as those in Example 1, the same reference numerals are assigned to the same components and the description thereof is omitted.

[0036] FIG. 5 is a schematic configuration diagram of a film forming apparatus according to Example 2 of the present invention. In FIG. 5, the internal configuration of the apparatus is schematically shown, and some configurations are shown by schematic cross-sectional views. Also, the film forming apparatus 1A according to this example includes a chamber 10 and a film forming unit 100A. The film forming unit 100A includes a film forming source 110, a restricting member 120, a radiative cooling member 130A, and a thickness meter 140.

[0037] In this embodiment, it is different from Embodiment 1 in that a plurality of radiative cooling members 130A are provided. For each radiative cooling member 130A, similar to Embodiment 1, a cooling surface 131A is provided, and a pipe 132A through which a refrigerant for controlling the temperature circulates is provided. And the plurality of radiative cooling members 130A are arranged such that the normal line of the surface of each cooling surface 131A intersects the center (near the center) of the film formation range R. Note that the shape of the surface of the cooling surface 131A may be a flat surface or a curved surface that is concave. That is, as described above, as long as the normal line of the surface of the cooling surface 131A intersects the center of the film formation range R, the shape of the surface is not limited. Depending on the arrangement position of the radiative cooling member 130A, by setting the inclination angle and the surface shape of the cooling surface 131A, it is possible to make the normal line of the surface of the cooling surface 131A intersect the center of the film formation range R. By adopting the configuration of this embodiment, compared with Embodiment 1, the height of the radiative cooling member 130A can be suppressed, so that the degree of freedom in design can be increased. This is particularly effective when the height of the radiative cooling member 130A is restricted due to design constraints.

[0038] Note that also in this embodiment, as the configuration for controlling the temperature of the radiative cooling member 130A, the case of using a refrigerant is shown, but as described in Embodiment 1, the configuration for controlling the temperature is not limited, and 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 by a thickness meter 140 such as a crystal thickness meter. However, as described in Embodiment 1, a configuration in which the thickness of the film formed by the film-forming material on the cooling surface 131A is derived using parameters including the measured film formation time can also be adopted. Also in this embodiment, by adopting a configuration in which a plurality of thickness meters 140 are arranged, it is also possible to individually control the temperature of the radiative cooling member 130A at a plurality of locations, or to determine a temperature correction amount from the average value of the film thickness for each location or the like. Furthermore, also in this embodiment, when adopting a configuration in which film formation is performed on the entire substrate S while moving the film formation unit 100A, it may be controlled such that the temperature control amount of the radiative cooling member 130A changes according to the movement of the film formation range R.

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

[0040] As shown in Fig. 6(a), in the display region 561 of the organic EL display device 560, a plurality of pixels 562 each including a light emitting element are arranged in a matrix. Although details will be described later, each of the light emitting elements has a structure including an organic layer sandwiched between a pair of electrodes. Here, the pixel refers to the minimum unit that enables display of a desired color in the display region 561. In the case of the organic EL display device according to the present embodiment, the pixel 562 is constituted by a combination of a first light emitting element 562R, a second light emitting element 562G, and a third light emitting element 562B that exhibit mutually different emissions. The pixel 562 is often 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, and is not particularly limited as long as it is at least one color or more.

[0041] FIG. 6(b) is a partial cross-sectional schematic view taken along line A-B of FIG. 6(a). The pixel 562 has an organic EL element including a first electrode (anode) 564, a hole transport layer 565, one of light-emitting layers 566R, 566G, 566B, an electron transport layer 567, and a second electrode (cathode) 568 on a substrate 563. Among these, the hole transport layer 565, the light-emitting layers 566R, 566G, 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, 566B are formed in patterns corresponding to light-emitting elements (sometimes described as organic EL elements) that emit red, green, and blue light, respectively. Also, 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 a plurality of light-emitting elements 562R, 562G, 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 the first electrode 564 and the second electrode 568 from being short-circuited by foreign matter. Further, since the organic EL layer deteriorates due to moisture and oxygen, a protective layer 570 for protecting the organic EL element from moisture and oxygen is provided.

[0042] In FIG. 6(b), the hole transport layer 565 and the electron transport layer 567 are shown as one layer, but depending on the structure of the organic EL display element, they may be formed of a plurality of layers including a hole blocking layer and an electron blocking layer. Also, 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 substrate 563 on which a circuit (not shown) for driving the organic EL display device and the first electrode 564 are formed is prepared.

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

[0045] The substrate 563 on which the insulating layer 569 is patterned is carried into a first film-forming apparatus, the substrate is held by a substrate support unit, and 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 evaporation. Actually, since the hole transport layer 565 is formed to be larger in size than the display region 561, a high-definition mask is not required.

[0046] Next, the substrate 563 on which the hole transport layer 565 is formed is carried into a second film-forming apparatus and held by a substrate support unit. Alignment between the substrate and the mask (first alignment and second alignment) is performed, the substrate is placed on the mask, and a light-emitting layer 566R that emits red light is formed in a portion where the element that emits red light on the substrate 563 is arranged.

[0047] Similar to the formation of the light-emitting layer 566R, a light-emitting layer 566G that emits green light is formed by a third film-forming apparatus, and further, a light-emitting layer 566B that emits blue light is formed by a fourth film-forming 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-forming apparatus. The electron transport layer 567 is formed as a common layer for the three-color light-emitting layers 566R, 566G, and 566B.

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

[0049] After the substrate 563 with the patterned insulating layer 569 is carried into the film forming apparatus and until the film formation of the protective layer 570 is completed, if it is exposed to an atmosphere containing moisture or oxygen, the light-emitting layer made of the organic EL material may be deteriorated by moisture or oxygen. Therefore, in this example, the loading and unloading of the substrate between the film forming apparatuses are performed under a vacuum atmosphere or an inert gas atmosphere.

Explanation of Signs

[0050] 1,1A: Film forming apparatus 10: Chamber 20: Rail 100,100A: Film forming unit 110: Film forming source 120: Limiting member 121: Opening 130,130A: Radiation cooling member 131,131A: Cooling surface 131a: Opening 132,132A: Pipe 140: Thickness gauge 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 with a film forming material emitted from a film forming source within 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 area of the substrate and having a cooling surface capable of heat exchange by radiation; A film forming apparatus, 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 area.

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 area.

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 area.

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

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

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 parameters including the measured film forming time.

9. Using 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 power of the thickness of the film. The film forming apparatus according to claim 1.

10. The film forming apparatus according to claim 9, wherein the X is set according to the film forming material and 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 with a film forming material emitted from a film forming source in a chamber, wherein a radiative cooling member having a cooling surface capable of heat exchange by radiation is provided at a position that does not obstruct a path of the film forming material from the film forming source to the film forming range of the substrate, a step of obtaining a thickness of a film formed by the film forming material formed on the cooling surface, a step of controlling a temperature of the radiative cooling member according to the obtained thickness of the film, and the film forming method is characterized by including these steps.

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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