Film forming apparatus

Abstract

The present invention employs a film forming apparatus for forming a film on a substrate, the film forming apparatus comprising: an electrostatic chuck that includes an attraction surface, a first electrode, and a second electrode, and that attracts the substrate via the attraction surface by having a voltage applied to the first electrode and the second electrode; a measurement means for measuring the value of capacitance between the first electrode and the second electrode; and a detection means for detecting the level of adsorbed water adsorbed on the electrostatic chuck, on the basis of the value of the capacitance.

Description

Film forming equipment

[0001] The present invention relates to a film forming apparatus.

[0002] In recent years, flat panel display devices such as organic electroluminescence (EL) display devices have been used as display screens for monitors, televisions, smartphones, and other devices. An EL display panel has a structure in which an organic layer that generates light is formed between two opposing electrodes (a cathode and an anode). When forming an EL display panel using a film deposition system, the peripheral edge of the substrate is held by a substrate holder placed in the chamber of the film deposition system, and an evaporation source located at the bottom of the chamber is heated to release a metal or organic evaporation material, which is then deposited on the underside of the substrate through a mask. However, as the substrate size increases, the center of the substrate tends to bend more due to its own weight, which can affect deposition accuracy.

[0003] Therefore, in order to reduce the bending of the substrate, a technique for holding the substrate using an electrostatic chuck (ESC: Electrostatic chuck) has been proposed. Patent Document 1 (Japanese Patent Laid-Open Publication No. 2022-155114) discloses a film forming apparatus including an electrostatic chuck and a detector that detects the capacitance of the electrode portion of the electrostatic chuck. In Patent Document 1, the voltage applied to the electrostatic chuck is controlled based on a change in the capacitance measured based on the output from the detector.

[0004] Although the inside of the film-forming apparatus is usually under a vacuum, it may be exposed to the atmosphere during maintenance, etc. In this case, the inside of the film-forming apparatus is exposed to the atmosphere, and moisture in the atmosphere may be adsorbed to the electrostatic chuck. If film formation is performed while moisture is adsorbed to the electrostatic chuck, the adsorption force may decrease, causing poor adsorption.

[0005] In view of this, Patent Document 2 (Japanese Patent No. 6326295) discloses a processing device including an electrostatic chuck, a cooling device, and a lamp heating device. In Patent Document 2, the cooling device cools the electrostatic chuck, and the lamp heating device evaporates moisture adhering to the electrostatic chuck.

[0006] JP 2022-155114 A Patent No. 6326295 A

[0007] However, with conventional methods, it was not possible to detect the level of moisture adsorbed to the electrostatic chuck, which could result in excessively long drying and heating times to remove the moisture, which could delay the resumption of film deposition and extend the takt time.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a technique for detecting the level of moisture adsorbed to an electrostatic chuck that adsorbs and holds a substrate in a film formation apparatus.

[0009] The present invention employs the following configuration: A film formation apparatus for forming a film on a substrate, comprising: an electrostatic chuck having an attracting surface and first and second electrodes, and attracting the substrate with the attracting surface by applying a voltage to the first and second electrodes, a measuring means for measuring a value of electrostatic capacitance between the first and second electrodes, and a detecting means for detecting a level of adsorbed water attracted to the electrostatic chuck based on the value of electrostatic capacitance.

[0010] According to the present invention, it is possible to provide a technique for detecting the level of moisture adsorbed on the surface of an electrostatic chuck that adsorbs and holds a substrate in a film deposition apparatus.

[0011] Schematic plan view showing the configuration of a film formation apparatus; Cross-sectional view showing the internal configuration of a film formation chamber; Cross-sectional view showing the configuration of an electrostatic chuck and the influence of moisture adsorption; Block diagram explaining capacitance detection in Example 1; Graph showing time change in capacitance value; Cross-sectional view showing the internal configuration of a film formation chamber in Example 2; Block diagram explaining capacitance detection in Example 3; Figures explaining a manufacturing method of an electronic device

[0012] The following describes in detail embodiments of the present invention. However, the following embodiments merely exemplify preferred configurations of the present invention, and the scope of the present invention is not limited to these configurations. Furthermore, unless otherwise specified, the hardware and software configurations, processing flow, manufacturing conditions, dimensions, materials, shapes, and the like of the device in the following description are not intended to limit the scope of the present invention to these alone.

[0013] The present invention is suitable for a film formation apparatus that forms a thin film of a film formation material on the surface of a film formation target such as a substrate by evaporation or sputtering. The present invention can be understood as an electrostatic chuck, a detection device, a substrate holding device, a film formation apparatus, and a detection method or control method using these devices. The present invention can also be understood as an electronic device manufacturing apparatus, a control method therefor, and a method for manufacturing an electronic device. The present invention can also be understood as a program that causes a computer to execute the detection method or control method, or a storage medium storing the program. The storage medium may be a non-transitory storage medium that is readable by a computer.

[0014] In the present invention, any substrate material can be used, such as glass, resin, metal, or silicon. Any film-forming material can be used, such as organic or inorganic materials (metals or metal oxides). In the following description, the term "substrate" includes substrate materials on whose surfaces one or more films have already been formed. The technology of the present invention is typically applied to manufacturing equipment for electronic devices and optical components. It is particularly suitable for organic electronic devices, such as organic EL displays equipped with organic EL elements and organic EL display devices using such displays. The present invention can also be used in thin-film solar cells and organic CMOS image sensors.

[0015] <Example 1> (Apparatus Configuration) Fig. 1 is a plan view showing a schematic configuration of a film forming apparatus 1. Here, a manufacturing line for organic EL displays will be described. When manufacturing an organic EL display, a substrate of a predetermined size is carried into the manufacturing line, and after the organic EL and metal layers are formed, post-processing steps such as cutting the substrate are carried out.

[0016] The film forming apparatus 1 includes a transfer chamber 130 located in the center, and a plurality of film forming chambers 110 (110a to 110d) and mask stock chambers 120 (120a, 120b) located around the transfer chamber 130. The film forming chamber 110 includes a chamber in which a film forming process is performed on a substrate S. The mask stock chamber 120 stores masks before and after use. A transfer robot 140 installed in the transfer chamber 130 transfers the substrate S and the mask M into and out of the transfer chamber 130. The transfer robot 140 is, for example, a robot having a robot hand for holding the substrate S and the mask M attached to an articulated arm.

[0017] The pass chamber 150 transfers the substrate S flowing from the upstream side in the substrate transfer direction to the transfer chamber 130. The buffer chamber 160 transfers the substrate S, for which film formation processing has been completed in the transfer chamber 130, to another film formation cluster on the downstream side. When the transfer robot 140 receives the substrate S from the pass chamber 150, it transfers it to one of the multiple film formation chambers 110. The transfer robot 140 also receives the substrate S, for which film formation processing has been completed, from the film formation chamber 110 and transfers it to the buffer chamber 160.

[0018] 1 constitutes one film formation cluster, and other film formation clusters can be connected to the upstream or downstream side. A swirl chamber 170 for changing the direction of the substrate S is provided further upstream from the pass chamber 150 and further downstream from the buffer chamber 160. Each chamber, such as the film formation chamber 110, mask stock chamber 120, transfer chamber 130, buffer chamber 160, and swirl chamber 170, is maintained in a high vacuum state during the manufacturing process.

[0019] The film formation materials in the multiple film formation chambers 110a to 110d of the film formation apparatus 1 may be the same or different. For example, a film formation source of a different film formation material may be disposed in each of the film formation chambers 110a to 110d, and a layered structure may be formed as the substrate S moves sequentially through the film formation chambers 110a to 110d. Alternatively, film formation sources of the same film formation material may be disposed in each of the film formation chambers 110a to 110d, so that films may be formed in parallel on multiple substrates S. Alternatively, a first film formation material may be disposed in the film formation chambers 110a and 110c, and a second film formation material may be disposed in the film formation chambers 110b and 110d, and the film formation may be controlled so that a first layer is formed in the film formation chamber 110a or 110c, and then a second layer is formed in the film formation chamber 110b or 110d.

[0020] Depending on the type of electrostatic chuck, the force of attraction of the substrate can be increased when a conductive material is attached to the substrate. In such a case, the electrostatic chuck can be effectively used when a thin film of a metal material that will become an electrode layer has already been formed in the region of the substrate where the organic EL element will be formed (typically the center of the substrate). For example, when an electrode layer is formed on a substrate in the film formation chamber 110a, and organic layers are sequentially formed in the film formation chambers 110b to 110d, it is effective to place electrostatic chucks in the film formation chambers 110b to 110d.

[0021] 2 is a cross-sectional view showing the internal configuration of the film formation chamber 110. In the film formation chamber 110, a series of film formation processes are carried out, such as receiving the substrate S and mask M from the transfer robot 140, handing over the substrate S and mask M to the transfer robot 140, alignment to adjust the relative positional relationship between the substrate S and mask M, fixing the substrate S to the mask M, and film formation. In the following description, an XYZ Cartesian coordinate system is used in which the vertical direction is the Z direction, and rotation around the Z axis is represented by θ.

[0022] The film formation chamber 110 includes a chamber 200. The interior of the chamber 200 is maintained in a vacuum atmosphere or an inert gas atmosphere such as nitrogen gas during film formation. An electrostatic chuck C, a substrate support 210, a mask table 221, and an evaporation source 240 (film formation source) are provided inside the chamber 200. The film formation chamber 110 includes a vacuum mechanism for creating a vacuum inside the chamber.

[0023] The mask M has an opening pattern corresponding to the thin film pattern to be formed on the substrate. For example, a metal mask in which a metal foil on which a pattern is formed is supported by a frame around the periphery can be used as the mask M. The mask M is placed on a mask table 221. In the configuration of this embodiment, the substrate S is positioned and placed on the mask, and then film formation is performed.

[0024] The substrate support part 210 has a plurality of claw-shaped supports 210a for receiving the substrate S transported into the film formation chamber. The electrostatic chuck C is a substrate holding means inside the film formation chamber, and attracts and holds the substrate S supported by the substrate support part 210 by electrostatic force on an attracting surface. When the surface of the substrate S that comes into contact with the mask M (the surface on which a film is to be formed) is defined as a first surface and the surface opposite to the first surface is defined as a second surface, the electrostatic chuck C abuts against the second surface of the substrate S.

[0025] The substrate support part 210 may also have a pressing tool that presses the surface (second surface) opposite to the first surface of the substrate S supported by the support tool 210a. By pressing the substrate S from the side opposite to the support tool 210a, the substrate S can be held by the substrate support part 210 in addition to the electrostatic chuck C, making the substrate S more stable. A magnet may also be placed above the electrostatic chuck C to attract the mask M.

[0026] The evaporation source 240 is a film forming means including a container such as a crucible for accommodating an evaporation material, a heater, a shutter, a driving mechanism, an evaporation rate monitor, etc. The film forming source is not limited to an evaporation source, and a sputtering device may also be used.

[0027] An electrostatic chuck actuator 252 and an alignment stage 280 are provided at the upper exterior of the chamber 200. The electrostatic chuck actuator 252 drives the electrostatic chuck C in the Z-axis direction via a shaft or the like to raise and lower it. This changes the relative distance between the substrate S and the mask M in a direction intersecting a plane along the film formation surface of the substrate S. The electrostatic chuck actuator 252 is composed of a motor and a ball screw, a motor and a linear guide, or the like. The electrostatic chuck C may be considered to be the substrate holding device, or the electrostatic chuck C and the power supply 290 may be considered to be a combination of the substrate holding device. The control unit 270 may also be considered to be included in the substrate holding device. The electrostatic chuck actuator 252 may also be considered to be included in the substrate holding device.

[0028] When the electrostatic chuck C holds the substrate S supported by the substrate support part 210, the electrostatic chuck actuator 252 first lowers the electrostatic chuck C so that the electrostatic chuck C abuts on or approaches sufficiently close to the substrate S. Then, the control part 270 controls the power supply 290 to apply a predetermined attracting voltage to the electrode embedded in the electrostatic chuck C. This enables the electrostatic chuck C to hold the substrate S.

[0029] Then, during alignment, the electrostatic chuck actuator 252 further lowers the electrostatic chuck C to bring the substrate S closer to the mask M. Then, the alignment stage 280 performs alignment. Then, during film formation, the evaporation source 240 releases the film formation material. When film formation is complete, the electrostatic chuck actuator 252 raises the electrostatic chuck C to transfer the substrate S on which the film has been formed to a transfer robot. Then, the voltage applied to the electrostatic chuck C is set to a predetermined peeling voltage (for example, 0 V), thereby releasing the substrate from its grip.

[0030] The alignment stage 280 is an alignment means that moves the substrate S in the X and Y directions and rotates it in the θ direction. The alignment stage 280 adjusts the relative position of the substrate S and the mask M in a plane along the film formation surface of the substrate S. The alignment stage 280 includes a chamber fixing part 281 that is connected to and fixed in the chamber 200, an actuator part 282 for X, Y, θ movement, and a connection part 283 that is connected to the electrostatic chuck C.

[0031] The actuator unit 282 moves the substrate S in the X and Y directions and rotates it in the θ direction in accordance with control signals sent from the control unit 270. The actuator unit 282 may be an actuator in which an X actuator, a Y actuator, and a θ actuator are stacked. Alternatively, a UVW type actuator in which multiple actuators work together may be used. Note that while this embodiment is configured to adjust the position of the substrate S, it may also be configured to adjust the position of the mask M or to adjust both the substrate S and the mask M, as long as the substrate S and the mask M can be aligned relative to each other.

[0032] A camera 261 that performs optical imaging and generates image data is provided at the upper outside of the chamber 200. The camera 261 captures images through a vacuum sealing window provided in the chamber 200. In this embodiment, a plurality of cameras 261 are provided corresponding to the four corners of the substrate S. Each camera 261 is positioned so that its imaging range includes a substrate alignment mark provided at a corner of the substrate S and a mask alignment mark provided at a corner of the mask M.

[0033] During alignment, the camera 261 captures images of the substrate S and mask M and outputs image data to the control unit 270. The control unit 270 analyzes the captured image data and acquires position information of the substrate alignment mark and the mask alignment mark using techniques such as pattern matching processing. Then, based on the amount of misalignment between the substrate alignment mark and the mask alignment mark, it calculates the X and Y directions, movement distance, and rotation angle θ for moving the substrate S. The calculated movement amount is then converted into the drive amount for the stepping motor, servo motor, or the like provided in each actuator of the alignment stage 280, and a control signal is generated. Two-stage alignment may be performed using a low-resolution but wide-field-of-view camera for rough alignment and a narrow-field-of-view but high-resolution camera for fine alignment.

[0034] The control unit 270 is an information processing device that communicates with each component of the film forming apparatus 1 via control lines or wireless communication (not shown), receives data from each component, and sends signals to each component to control its operation. The control unit 270 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 270 are realized by the processor executing a program stored in the memory or storage. The computer may be a general-purpose personal computer, an embedded computer, or a PLC (programmable logic controller). Alternatively, some or all of the functions of the control unit 270 may be configured by a circuit such as an ASIC or FPGA. Note that a control unit 270 may be provided for each film forming chamber, or one control unit 270 may control multiple film forming chambers.

[0035] The power supply 290 is a high-voltage power supply device capable of supplying voltage to each component of the film forming apparatus 1 via conductive wires (not shown). The power supply 290 controls the polarity and magnitude of the applied voltage in accordance with instructions from the control unit 270. The power supply 290 can be considered a voltage supply means. By controlling the polarity and magnitude of the voltage (attraction voltage) applied to the electrode of the electrostatic chuck C, the attracting force to the substrate S can be controlled. Note that the power supply 290 and the control unit 270 may be considered to collectively constitute the power supply of the film forming apparatus.

[0036] The application of the present invention is not limited to the cluster-type film formation apparatus described above, but can also be applied to an in-line type film formation apparatus in which multiple chambers are connected through a vacuum, and a substrate held by a substrate carrier is moved between the chambers while a film is formed.

[0037] (Electrostatic Chuck) The electrostatic chuck C has a structure in which an electric circuit such as a metal electrode is embedded in a plate-shaped base material made of ceramic or the like. Generally, electrostatic chucks are classified into types such as a gradient force type, a Coulomb force type, and a Johnsen-Rahbek force type depending on the principle by which they attract a substrate, and in any of these types, the attracting force can be increased as the attracting voltage applied thereto is increased.

[0038] A gradient force-type electrostatic chuck attracts an object by utilizing an attractive force generated toward a region of a potential gradient (gradient) due to a potential difference between electrodes. The gradient force can be generated even when the object is an insulator, making it possible to hold even bare glass or glass substrates without conductive films. To generate the gradient force, an attraction voltage is applied so that the potential of the first electrode is higher than the reference potential of the object to be attracted and the potential of the second electrode is lower than the reference potential. To increase this gradient force, it is necessary to minimize the space between the electrodes and to arrange the electrodes closely together in order to make the potential gradient as steep as possible. Therefore, two comb-shaped electrodes with interdigitated protruding teeth are suitable for use in a gradient force-type electrostatic chuck.

[0039] Coulomb force-type electrostatic chucks attract objects by electrostatic attraction generated by applying positive and negative voltages to two electrodes, respectively. This type is effective when the object is a conductor. Therefore, it can effectively attract substrates with metal electrode layers already formed on them. When the object is floating (not connected to ground), both the positive and negative electrodes can be placed facing the object to generate polarization within the object, allowing it to be attracted. When the object is grounded, it can be attracted by at least one of the positive and negative electrodes. Coulomb force is generally stronger than gradient force. Furthermore, the larger the area of ​​the electrode facing the object, the stronger the attraction force. Therefore, to increase the attraction force, the ratio of the electrode area to the electrostatic chuck area must be as large as possible.

[0040] A Johnson-Rahbek force type electrostatic chuck attracts a conductive object by passing a leakage current through the positive electrode, the object, and the negative electrode in that order. A dielectric with a volume resistivity within a specified range must be placed between the electrode and the object. The Johnson-Rahbek force is generally stronger than the Coulomb force. Furthermore, even with a Johnson-Rahbek force type electrostatic chuck, the greater the contact area with the object, the stronger the attraction force.

[0041] (Adsorption of Moisture to Electrostatic Chuck) As described above, the inside of the film formation apparatus is usually placed in a vacuum atmosphere, so that unnecessary moisture is not present. However, when the film formation apparatus 1 is opened to the atmosphere, for example, during maintenance, the inside of the film formation apparatus is exposed to the atmosphere, and moisture in the atmosphere may be adsorbed to the electrostatic chuck C. If moisture is adsorbed to the electrostatic chuck C (particularly to the dielectric layer), the adsorption force may decrease, and the alignment accuracy may be reduced.

[0042] The moisture adsorbed to the electrostatic chuck C can be reduced to an amount that does not adversely affect the adsorption by removing it by natural drying under vacuum evacuation or by heating with a temperature control member, which will be described later. However, if the level of moisture (moisture amount) adsorbed to the electrostatic chuck C cannot be detected, the drying time or heating time may become excessively long, which may delay the timing for resuming film formation and lengthen the takt time.

[0043] 3A is a schematic cross-sectional view of the electrostatic chuck C. The electrostatic chuck C has a structure in which a positive electrode 250 (first electrode) and a negative electrode 260 (second electrode) are embedded in a substrate 255 made of ceramic or the like. The positive electrode 250 and the negative electrode 260 are connected to a power source 290. When a voltage is applied to the positive electrode 250 and the negative electrode 260 under the control of a control unit 270, an attraction force corresponding to the magnitude of the voltage is generated, and the substrate S is attracted to the positive electrode 250 and the negative electrode 260.

[0044] 3B shows a state in which the electrostatic chuck C does not adsorb any moisture or adsorbs only a small amount of moisture that does not affect the adsorption force. When a predetermined voltage is applied from the power supply 290, the electrostatic chuck C exerts an adsorption force (F1) of a desired magnitude corresponding to the applied voltage, thereby adsorbing the substrate S.

[0045] 3(c) shows a state in which the base material 255 of the electrostatic chuck C has adsorbed a certain amount of moisture, and the moisture level is high enough to affect the chucking force. When a predetermined voltage is applied from the power supply 290, the electrostatic chuck C can only exert an chucking force (F2) that is smaller than the desired chucking force (F1). As a result, there is a risk of chucking failure, such as misalignment during chucking or peeling of the substrate S. Therefore, in a film formation process using the film formation apparatus 1, it is necessary to periodically or at a desired timing check the state of moisture adsorption by the electrostatic chuck C, and if any moisture is adsorbed, it is necessary to remove the moisture.

[0046] A preferred manufacturing method for the electrostatic chuck C is to install the positive electrode 250, the negative electrode 260, and wiring on a plate-shaped substrate by thermal spraying, and then complete the substrate 255 by thermal spraying a ceramic or the like. In such a case, many porous structures may be formed on the surface coated by thermal spraying, which may easily adsorb moisture. Therefore, the method of the present invention is particularly effective. The electrostatic chuck C may be composed of multiple layers, for example, a layer having a temperature control function may be stacked in addition to a layer in which the positive electrode 250 and the negative electrode 260 are embedded.

[0047] FIG. 4 shows a configuration for detecting the level of moisture adsorbed by the electrostatic chuck C in this embodiment. A first switch 320, which can be switched between a connected state and a disconnected state, is provided on a conductor supplying power from the power supply 290 to the electrodes of the electrostatic chuck C. The film forming apparatus 1 also includes a capacitance detection unit 310 connected to both electrodes of the electrostatic chuck C. The capacitance detection unit 310 may be a capacitance sensor, such as a multi-tester, that measures the capacitance value between the two electrodes and outputs the measured value as an analog signal to the control unit 270. The capacitance sensor detects a higher capacitance value as the amount of moisture adsorbed by the electrostatic chuck C increases. A second switch 325, which can be switched between a connected state and a disconnected state, is also provided on the conductor connecting the capacitance detection unit 310 to the electrostatic chuck C. Each switch can be considered a switching device.

[0048] The control unit 270 converts the detection signal from the capacitance detection unit 310 into a digital signal and compares it with a capacitance value previously measured and stored in memory to determine whether or not moisture has been adsorbed and the degree of adsorption. In this embodiment, the capacitance detection unit 310 corresponds to a measuring means for measuring the capacitance value. The capacitance detection unit 310 and the control unit 270 may be considered collectively as a measuring means. The measuring means is typically connected to an electrical path between a power source and an electrode. The control unit 270 may also be considered as a detecting means for detecting the level of adsorbed moisture based on the measured capacitance value.

[0049] The film forming apparatus 1 may also be provided with a notification unit 275 that receives instructions from the control unit 270 and notifies the user of the status of moisture adsorption by the electrostatic chuck C. The notification unit 275 may have any configuration as long as it can notify the user of information. For example, if the control unit 270 is a computer, the computer's monitor or speaker may be used, or a dedicated lamp or speaker for notifying the user of adhesion of foreign matter may be provided. When the control unit 270 detects an abnormal state regarding the electrostatic chuck C that requires notification, the control unit 270 notifies the user of the information via the notification unit 275. The notification unit 275 may further notify the user of the amount of moisture and the time required to remove the moisture. Alternatively, the control unit 270 may determine whether the electrostatic chuck C is ready to adsorb the substrate S. Based on the result of this determination, the control unit 270 may start adsorption of the substrate S by the electrostatic chuck C in the next film forming process. Alternatively, the control unit 270 may determine the time until the electrostatic chuck C is ready to adsorb the substrate S.

[0050] Furthermore, when a state such as a high moisture content is detected, the control unit 270 may increase the set value of the attraction voltage to be applied during the next film formation so as to reliably attract the substrate S, instead of or in addition to notification by the notification unit 275. Specifically, when the capacitance detection value is higher than a predetermined value or when the moisture content calculated from the detection value is higher than a predetermined amount, the set value of the attraction voltage is increased.

[0051] The capacitance detection unit 310 of this embodiment detects capacitance when no voltage is applied from the power supply 290 and therefore when the substrate S is not being attracted. Furthermore, by providing the first switch 320 and the second switch 325 as shown in the figure, it is possible to reliably switch paths between when a voltage is applied and when capacitance is detected. That is, when capacitance is detected, the first switch 320 is in a disconnected state and the second switch 325 is in a connected state (first state). Furthermore, when voltage is applied, the first switch 320 is in a connected state and the second switch 325 is in a disconnected state (second state). This eliminates the need to use a device that can handle high voltages as the capacitance detection unit 310, thereby simplifying the configuration.

[0052] In this embodiment, the state of the electrostatic chuck C is preferably detected when the electrostatic chuck C is not attracting the substrate S. Examples of the timing include when the film forming apparatus is installed, after a predetermined number of substrates have been formed, after the apparatus has been operated for a predetermined period of time, and during regular or special maintenance.

[0053] (Capacitance Change and Moisture Removal) FIG. 5 is a graph showing the change in capacitance over time in this embodiment. The horizontal axis represents the elapsed time, and the vertical axis represents the detected capacitance value. As described above, the capacitance value reflects the amount of water adsorbed by the electrostatic chuck C, and therefore, FIG. 5 can be said to reflect the change in the amount of adsorbed water. Furthermore, Th1 on the vertical axis (11 nF in this embodiment) is the capacitance value that serves as a threshold for determining whether the electrostatic chuck C can exert a sufficient adsorption force. Note that the control unit 270 may use a capacitance threshold or a moisture content threshold as a criterion for determining whether to start adsorption.

[0054] In this embodiment, the electrostatic chuck C is dried and the adsorbed moisture is removed by evacuating the interior of the film forming apparatus. After the graph begins, evacuation begins at time T1. As the moisture level decreases due to drying, the capacitance value also decreases. When the capacitance value becomes equal to or less than Th1, the control unit determines that the electrostatic chuck C has sufficiently dried to be able to exert the adsorption force required to adsorb the substrate S. Therefore, the period from time T1 to time T2 (Term 1) is a drying period (moisture removal period), and the period from time T2 onward (Term 2) can be considered an adsorption period.

[0055] 5 are merely examples, and should be appropriately changed depending on the material and configuration of the electrostatic chuck C, the required chucking force, etc. For example, the capacitance value varies depending on the electrode arrangement pattern of the electrostatic chuck C, the electrode thickness, the thickness and dielectric constant of the dielectric layer, the type of impregnating agent in the material, the dimensions of the electrostatic chuck C, etc. Furthermore, the change in the capacitance value due to evacuation varies depending on the evacuation speed, the degree of vacuum, the surface roughness of the electrostatic chuck C, the type of impregnating agent, etc.

[0056] The control unit 270 may notify the user of the detected value itself, may notify the moisture level determined from the detected value, or may notify the remaining drying time at any time. Alternatively, the control unit 270 may simply notify whether adsorption is possible. The stage at which the notification is made can be set arbitrarily. Furthermore, rather than notifying the user, or in addition to notifying the user, the detected value and information based thereon may be used for subsequent control by the control unit 270. An example of subsequent control is the start of a film formation process.

[0057] As described above, according to this embodiment, the state of moisture adsorbed to the electrostatic chuck C can be detected based on the detected value of the electrostatic capacitance, and therefore, the user can be prompted to take appropriate measures, such as removing the moisture by vacuum drying the electrostatic chuck C. As a result, film formation is not performed in a state in which the adsorption force of the electrostatic chuck C is reduced, which enables accurate film formation and prevents the takt time from becoming longer.

[0058] Second Embodiment Next, a second embodiment of the present invention will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0059] As shown in FIG. 6 , the film formation apparatus 1 of the present invention may include a temperature control member 300 for controlling the temperature of the electrostatic chuck C. Typically, the temperature control member 300 is disposed in contact with the electrostatic chuck C as shown. The temperature control member 300 may be configured, for example, as a plate-shaped substrate that is disposed in contact with the electrostatic chuck C, with a pipe through which a fluid such as water or oil can pass. The temperature control member 300 controls the temperature of the electrostatic chuck C by receiving a temperature-controlled fluid from an external fluid supply unit. The temperature control in this embodiment includes a heating process for heating the electrostatic chuck C to evaporate moisture, for example, after maintenance after exposure to the atmosphere. Furthermore, the temperature control may include a cooling process for cooling the electrostatic chuck C during film formation to suppress temperature rise and prevent alteration or degradation of the organic material.

[0060] The temperature control method is not limited to the example shown in the figure. For example, for heating purposes, a lamp or a sheath heater may be used, or heating may be performed by radiant heat inside the chamber. Furthermore, the electrostatic chuck C itself may also serve as a temperature control member. Furthermore, a temperature control member for cooling may be provided separately from a temperature control member for heating.

[0061] According to the configuration of this embodiment, the moisture adsorbed to the electrostatic chuck C can be removed more quickly. Therefore, the takt time can be further shortened. Furthermore, since the provision of a temperature control member for adjusting the temperature of the electrostatic chuck C (or the substrate S) is a common configuration in the film forming apparatus 1, it is possible to remove moisture while suppressing cost increases by utilizing existing members.

[0062] Third Embodiment Next, a third embodiment of the present invention will be described. The same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

[0063] 7 shows a configuration for detecting moisture adsorbed to the electrostatic chuck C in this embodiment. A capacitance detection unit 310 in this embodiment is provided between the power supply 290 and the electrostatic chuck C. The capacitance detection unit 310 in this embodiment has the same function as in the first embodiment, that is, measuring the capacitance value between the two electrodes and outputting the result to the control unit 270. However, there is a possibility that the capacitance measurement may be performed even while the adsorption voltage from the power supply 290 is being applied. Therefore, the capacitance detection unit 310 in this embodiment is required to have the performance to withstand the passage of a high voltage.

[0064] In this embodiment, as in the first and second embodiments, the greater the amount of moisture adsorbed by the electrostatic chuck C, the higher the detected capacitance value. Therefore, it is possible to notify a user of the moisture content of the electrostatic chuck C. In particular, in this embodiment, the capacitance value can be constantly monitored under the same conditions as when an actual substrate S is adsorbed, and therefore, detection processing can be performed under the same conditions as when the electrostatic chuck is actually used.

[0065] <Method for Manufacturing Electronic Device> Next, an example of a method for manufacturing an electronic device using the film forming apparatus according to this embodiment will be described. Below, the configuration of an organic EL display device will be shown as an example of the electronic device, and a method for manufacturing the organic EL display device will be illustrated.

[0066] First, the organic EL display device to be manufactured will be described. Fig. 8(a) is an overall view of the organic EL display device 700, and Fig. 8(b) shows the cross-sectional structure of one pixel.

[0067] As shown in FIG. 8A , a display region 701 of an organic EL display device 700 includes a plurality of pixels 702 arranged in a matrix, each pixel 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 region 701. In the organic EL display device according to this embodiment, each pixel 702 is configured by a combination of a first light-emitting element 702R, a second light-emitting element 702G, and a third light-emitting element 702B, which emit light different from one another. While the pixel 702 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.

[0068] 8(b) is a partial cross-sectional schematic diagram taken along line B-B in FIG. 8(a). A pixel 702 is composed of a plurality of light-emitting elements, each of which has, on a substrate 703, a first electrode (anode) 704, a hole transport layer 705, one of light-emitting layers 706R, 706G, or 706B, an electron transport layer 707, and a second electrode (cathode) 708. Of these, the hole transport layer 705, the light-emitting layers 706R, 706G, or 706B, and the electron transport layer 707 correspond to organic layers. In this embodiment, the light-emitting layer 706R is an organic EL layer that emits red light, the light-emitting layer 706G is an organic EL layer that emits green light, and the light-emitting layer 706B is an organic EL layer that emits blue light. The light-emitting layers 706R, 706G, and 706B are formed in patterns corresponding to the light-emitting elements (sometimes referred to as organic EL elements) that emit red, green, and blue light, respectively.

[0069] Furthermore, the first electrode 704 is formed separately for each light-emitting element. The hole transport layer 705, the electron transport layer 707, and the second electrode 708 may be formed in common for the plurality of light-emitting elements 702R, 702G, and 702B, or may be formed for each light-emitting element. Note that an insulating layer 709 is provided between the first electrodes 704 to prevent short-circuiting between the first electrode 704 and the second electrode 708 due to foreign matter. Furthermore, because the organic EL layer deteriorates due to moisture and oxygen, a protective layer 710 is provided to protect the organic EL element from moisture and oxygen.

[0070] 8(b), the hole transport layer 705 and the electron transport layer 707 are shown as single layers, but depending on the structure of the organic EL display element, they may be formed of multiple layers including a hole blocking layer and an electron blocking layer. Furthermore, a hole injection layer having an energy band structure that can facilitate the injection of holes from the first electrode 704 to the hole transport layer 705 can be formed between the first electrode 704 and the hole transport layer 705. Similarly, an electron injection layer can be formed between the second electrode 708 and the electron transport layer 707.

[0071] Next, an example of a method for manufacturing an organic EL display device will be specifically described.

[0072] First, a circuit (not shown) for driving the organic EL display device and a substrate (mother glass) 703 on which first electrodes 704 are formed are prepared.

[0073] An acrylic resin is formed by spin coating on the substrate 703 on which the first electrode 704 is formed, and the acrylic resin is patterned by lithography so as to form an opening in the portion where the first electrode 704 is formed, thereby forming an insulating layer 709. This opening corresponds to the light-emitting region where the light-emitting element actually emits light.

[0074] The substrate 703 on which the insulating layer 709 has been patterned is placed on a substrate carrier on which an adhesive member is arranged. The substrate 703 is held in place by the adhesive member. The substrate is then carried into a first organic material deposition apparatus, and after being inverted, a hole transport layer 705 is deposited as a common layer on the first electrode 704 in the display area. The hole transport layer 705 is deposited by vacuum deposition. In practice, the hole transport layer 705 is formed to be larger than the display area 701, so a high-resolution mask is not required.

[0075] Next, the substrate 703 on which the hole transport layer 705 has been formed is carried into a second organic material film forming apparatus. The substrate and a mask are aligned, and the substrate is placed on the mask. A red light-emitting layer 706R is formed on the portion of the substrate 703 where the red light-emitting element is to be disposed.

[0076] Similar to the formation of the light-emitting layer 706R, a green-emitting light-emitting layer 706G is formed by a third organic material film formation apparatus, and then a blue-emitting light-emitting layer 706B is formed by a fourth organic material film formation apparatus. After the formation of the light-emitting layers 706R, 706G, and 706B is completed, an electron transport layer 707 is formed over the entire display region 701 by a fifth film formation apparatus. The electron transport layer 707 is formed as a layer common to the three light-emitting layers 706R, 706G, and 706B.

[0077] The substrate on which the electron transport layer 707 has been formed is moved to a metal evaporation material deposition device, where a second electrode 708 is deposited.

[0078] Thereafter, the substrate is transferred to a plasma CVD device, where a protective layer 710 is formed, thereby completing the film formation process on the substrate 703. After inversion, the adhesive member is peeled off from the substrate 703, thereby separating the substrate 703 from the substrate carrier. Thereafter, the organic EL display device 700 is completed through cutting.

[0079] If the substrate 703 on which the insulating layer 709 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 710, the light-emitting layer made of an organic EL material may be deteriorated by the moisture or oxygen. Therefore, in this embodiment, the substrate is carried in and out of the film-forming apparatus in a vacuum atmosphere or an inert gas atmosphere.

[0080] 1: film forming apparatus, 270: control unit, 310: capacitance detection unit, C: electrostatic chuck, S: substrate

Claims

1. A film formation apparatus for forming a film on a substrate, comprising: an electrostatic chuck having an adsorption surface, a first electrode and a second electrode, and adsorbing the substrate by the adsorption surface when a voltage is applied to the first electrode and the second electrode; a measuring means for measuring a value of electrostatic capacitance between the first electrode and the second electrode; and a detecting means for detecting a level of adsorbed water adsorbed to the electrostatic chuck based on the value of electrostatic capacitance.

2. The film forming apparatus according to claim 1, wherein said detection means detects the level of said adsorbed water based on a change in the value of said capacitance over time.

3. The film deposition apparatus according to claim 1 or 2, characterized in that the detection means determines whether or not the substrate can be attracted by the electrostatic chuck based on the detected level of the adsorbed water.

4. The film deposition apparatus according to claim 3, characterized in that, after the detection means determines that the substrate can be attracted by the electrostatic chuck, attraction for film deposition onto the substrate is started.

5. The film forming apparatus according to claim 1 or 2, further comprising a temperature adjusting member that adjusts the temperature of the electrostatic chuck based on the level of the adsorbed water detected by the detection means.

6. The film forming apparatus according to claim 1 or 2, further comprising a temperature adjusting member that adjusts the temperature of the electrostatic chuck based on the value of the electrostatic capacitance measured by the measuring means.

7. The film forming apparatus according to claim 1 or 2, characterized in that the adsorbed water can be removed from the electrostatic chuck by vacuum evacuation.

8. The film forming apparatus according to claim 1 or 2, characterized in that the detection means determines that the amount of the adsorbed water is greater as the detected capacitance value is higher.

9. The film forming apparatus according to claim 1 or 2, further comprising a voltage supply means for supplying a voltage to the first electrode and the second electrode when the electrostatic chuck attracts the substrate.

10. The film forming apparatus according to claim 9, further comprising a switching means for switching between a first state in which the first electrode and the second electrode are connected to the measuring means and not connected to the voltage supply means, and a second state in which the connection between the measuring means and the first electrode and the second electrode is cut off.

11. The film forming apparatus according to claim 9, wherein the measuring means is connected to an electric path between the first electrode and the second electrode and the voltage supplying means.

12. The film forming apparatus according to claim 1 or 2, characterized in that the dielectric layer of the electrostatic chuck is formed by thermal spraying.

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