Film forming apparatus

Abstract

To provide a technique for detecting the level of moisture adsorbed onto an electrostatic chuck, which electrostatically attracts and holds a substrate in a film forming apparatus.SOLUTION: A film forming apparatus for forming a film on a substrate includes: an electrostatic chuck that includes an attraction surface, a first electrode and a second electrode and attracts a substrate via the attraction surface by having a voltage applied to the first electrode and the second electrode; measurement means for measuring a value of a capacitance between the first electrode and the second electrode; and detection means for detecting a level of adsorbed water adsorbed on the electrostatic chuck on the basis of the value of the capacitance.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] In recent years, flat panel display devices such as organic EL display devices have been used as display screens for monitors, televisions, smartphones, etc. The panel of an organic EL display device has a structure in which an organic layer that causes light emission is formed between two opposing electrodes (cathode electrode, anode electrode). When forming an organic EL display panel using a film forming apparatus, the peripheral portion of the substrate is held by a substrate holder disposed in the chamber of the film forming apparatus, and an evaporation source provided below the chamber is heated to release a vapor deposition material of a metal or an organic substance, which is then vapor deposited on the lower surface of the substrate through a mask. However, as the size of the substrate increases, the deflection due to the self-weight of the central portion of the substrate increases, which may affect the vapor deposition accuracy.

[0003] Therefore, in order to reduce the deflection of the substrate, a technique of holding the substrate using an electrostatic chuck (ESC) has been proposed. Patent Document 1 (Japanese Patent Application Laid-Open 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 the change in capacitance measured based on the output from the detector.

[0004] Here, although the inside of the film forming apparatus is usually in a vacuum atmosphere, it may be opened to the atmosphere during maintenance or the like. At this time, when the inside of the film forming apparatus is exposed to the atmosphere, moisture in the atmosphere may be adsorbed on the electrostatic chuck. If film formation is performed with moisture adsorbed on the electrostatic chuck, the adsorption force may decrease, causing adsorption failure.

[0005] Therefore, Patent Document 2 (Japanese Patent No. 6326295) discloses a processing apparatus including an electrostatic chuck, a cooling processing device, and a lamp heating device. In Patent Document 2, the electrostatic chuck is cooled by the cooling processing device, and the moisture adhering to the electrostatic chuck is evaporated by the lamp heating device.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, conventionally, it has not been possible to detect the level of moisture adsorbed on the electrostatic chuck. Therefore, the drying time and heating time for removing moisture may become excessively long, and there is a possibility that the timing of restarting film formation may be delayed and the tact time may be prolonged.

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

Means for Solving the Problems

[0009] The present invention employs the following configuration. That is, A film forming apparatus for forming a film on a substrate, having an adsorption surface, a first electrode, and a second electrode, and an electrostatic chuck that adsorbs the substrate by the adsorption surface when a voltage is applied to the first electrode and the second electrode, measuring means for measuring the value of the capacitance between the first electrode and the second electrode, Detection means for detecting the level of adsorbed water adsorbed on the electrostatic chuck based on the value of the capacitance; A film forming apparatus characterized by comprising the same.

Advantages of the Invention

[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 forming apparatus.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are merely illustrative of preferred configurations of the present invention, and the scope of the present invention is not limited to those configurations. Also, in the following description, the hardware configuration, software configuration, processing flow, manufacturing conditions, dimensions, materials, shapes, etc. of the apparatus are not intended to limit the scope of the present invention only to those unless otherwise specifically described.

[0013] The present invention is suitable for a film forming apparatus that forms a thin film of a film forming material on the surface of a film forming object such as a substrate by vapor deposition or sputtering. The present invention can be regarded as an electrostatic chuck, a detection device, a substrate holding device, and a film forming apparatus, and a detection method or a control method using these devices. The present invention can also be regarded as a manufacturing apparatus for electronic devices and its control method, and a manufacturing method for electronic devices. The present invention can also be regarded as a program for causing a computer to execute a detection method or a control method, and a storage medium storing the program. The storage medium may be a non-temporary storage medium readable by a computer.

[0014] As the material of the substrate in the present invention, any material such as glass, resin, metal, and silicon can be used. As the film forming material, any material such as organic materials and inorganic materials (metals, metal oxides) can be used. The "substrate" in the following description includes a substrate on which one or more film formations have already been performed on the surface of the substrate material. The technology of the present invention is typically applied to manufacturing apparatuses for electronic devices and optical members. In particular, it is suitable for organic electronic devices such as an organic EL display including an organic EL element and an organic EL display device using the same. The present invention can also be used for thin film solar cells and organic CMOS image sensors.

[0015] <Example 1> (Device Configuration) FIG. 1 is a plan view schematically showing the configuration of a film forming apparatus 1. Here, the manufacturing line of an organic EL display will be described. When manufacturing an organic EL display, a substrate of a predetermined size is carried into the manufacturing line, and after forming films of organic EL and metal layers, post-treatment steps such as cutting the substrate are performed. After that, a post-treatment step is performed.

[0016] The film forming apparatus 1 includes a transfer chamber 130 disposed at the center, and a plurality of film forming chambers 110 (110a to 110d) and mask stock chambers 120 (120a, 120b) disposed around the transfer chamber 130. The film forming chamber 110 includes a chamber in which a film forming process for the substrate S is performed. The mask stock chamber 120 stores masks before and after use. The 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 a multi-joint 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 the film forming process in the transfer chamber 130 has been completed to another film forming 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 plurality of film forming chambers 110. The transfer robot 140 also receives the substrate S for which the film forming process has been completed from the film forming chamber 110 and transfers it to the buffer chamber 160.

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

[0019] The film-forming materials in the plurality of film-forming chambers 110a to 110d of the film-forming apparatus 1 may be the same or different. For example, film-forming sources of different film-forming materials may be arranged in each of the film-forming chambers 110a to 110d, and a laminated structure may be formed while the substrate S sequentially moves through the film-forming chambers 110a to 110d. Also, by arranging film-forming sources of the same film-forming material in the film-forming chambers 110a to 110d, film formation may be performed in parallel on a plurality of substrates S. Further, a first film-forming material may be arranged in the film-forming chambers 110a and 110c, and a second film-forming material may be arranged in the film-forming chambers 110b and 110d. After forming the first layer in the film-forming chamber 110a or 110c, control may be performed to form the second layer in the film-forming chamber 110b or 110d.

[0020] Depending on the type of electrostatic chuck, when a conductor is attached to the substrate, the adsorption force of the substrate can be increased. In such a case, it is effectively adsorbable when a thin film of a metal material serving as an electrode layer has already been formed in the region (typically the central portion of the substrate) where the organic EL element is formed on the substrate. For example, when the organic layer is sequentially formed in the film-forming chambers 110b to 110d on the substrate on which the electrode layer is formed in the film-forming chamber 110a, it is effective to arrange an electrostatic chuck in the film-forming chambers 110b to 110d.

[0021] (Film-forming chamber) FIG. 2 is a cross-sectional view showing the internal configuration of the film-forming chamber 110. In the film-forming chamber 110, a series of film-forming processes such as receiving the substrate S and the mask M from the transfer robot 140, delivering the substrate S and the mask M to the transfer robot 140, alignment for adjusting the relative positional relationship between the substrate S and the mask M, fixing the substrate S to the mask M, and film formation are performed. In the following description, an XYZ orthogonal coordinate system with the vertical direction as the Z direction is used, and the rotation around the Z axis is represented by θ.

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

[0023] The mask M has an opening pattern corresponding to the thin film pattern formed on the substrate. As the mask M, for example, a metal mask that supports the periphery of a metal foil on which a pattern is formed with a frame can be used. The mask M is installed on the mask stage 221. In the configuration of this embodiment, after the substrate S is positioned and placed on the mask, film formation is performed.

[0024] The substrate support portion 210 has a plurality of receiving claw-shaped supports 210a for receiving the substrate S conveyed into the film formation chamber. The electrostatic chuck C is a substrate holding means inside the film formation chamber, and adsorbs and holds the substrate S supported by the substrate support portion 210 by electrostatic force on the adsorption surface. When the surface (film formation surface) in contact with the mask M on the two surfaces of the substrate S is defined as the first surface and the surface on the opposite side of the first surface is defined as the second surface, the electrostatic chuck C contacts the second surface of the substrate S.

[0025] Further, the substrate support portion 210 may have a pressing tool that presses the surface (second surface) of the substrate S opposite to the first surface supported by the support 210a. By pressing the substrate S from the side opposite to the support 210a with the pressing tool, the substrate S can be held not only by the electrostatic chuck C but also by the substrate support portion 210, so that the substrate S becomes more stable. Also, a magnet for attracting the mask M may be arranged above the electrostatic chuck C.

[0026] The evaporation source 240 is a film formation means including a container such as a crucible for containing a vapor deposition material, a heater, a shutter, a drive mechanism, an evaporation rate monitor, etc. Note that the film formation source is not limited to an evaporation source, and a sputtering device may be used.

[0027] On the upper outer side of the chamber 200, an electrostatic chuck actuator 252 and an alignment stage 280 are provided. The electrostatic chuck actuator 252 drives the electrostatic chuck C in the Z-axis direction via a shaft or the like to move it up and down. As a result, the relative distance between the substrate S and the mask M changes in a direction intersecting the plane along the film-forming 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, etc. The electrostatic chuck C may be considered as a substrate holding device, or the electrostatic chuck C and the power supply 290 together may be considered as a substrate holding device. Also, the control unit 270 may be considered to be included in the substrate holding device. Further, the electrostatic chuck actuator 252 may 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 portion 210, first, the electrostatic chuck actuator 252 lowers the electrostatic chuck C and brings the electrostatic chuck C into contact with or sufficiently close to the substrate S. Then, the control unit 270 controls the power supply 290 to apply a predetermined adsorption voltage to the electrodes embedded in the electrostatic chuck C. Thereby, the electrostatic chuck C can hold the substrate S.

[0029] Subsequently, 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. Subsequently, during film formation, the evaporation source 240 emits the film-forming material. When the film formation is completed, the electrostatic chuck actuator 252 raises the electrostatic chuck C and delivers the film-formed substrate S to the transfer robot. Then, by setting the applied voltage to the electrostatic chuck C to a predetermined release voltage (for example, 0V), the holding of the substrate is released.

[0030] The alignment stage 280 is an alignment means for moving the substrate S in the XY directions and rotating it in the θ direction. The alignment stage 280 adjusts the relative position between the substrate S and the mask M in a plane along the film-forming surface of the substrate S. The alignment stage 280 includes a chamber fixing portion 281 connected to and fixed to the chamber 200, an actuator portion 282 for performing XYθ movement, and a connection portion 283 connected to the electrostatic chuck C.

[0031] The actuator portion 282 moves the substrate S in the X and Y directions and rotates it in the θ direction according to a control signal transmitted from the control unit 270. As the actuator portion 282, an actuator in which an X actuator, a Y actuator, and a θ actuator are stacked may be used. Also, a UVW type actuator in which a plurality of actuators cooperate may be used. In this embodiment, the configuration is such that the position of the substrate S is adjusted. However, as long as the substrate S and the mask M can be relatively aligned, a configuration for adjusting the position of the mask M or a configuration for adjusting both the substrate S and the mask M may also be used.

[0032] A camera 261 for performing optical imaging and generating image data is provided at the upper outer side of the chamber 200. The camera 261 performs imaging through a vacuum sealing window provided in the chamber 200. In this embodiment, a plurality of cameras 261 corresponding to the four corners of the substrate S are provided. Each camera 261 is arranged such that the 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] At the time of alignment, the camera 261 images the substrate S and the mask M and outputs the image data to the control unit 270. The control unit 270 analyzes the captured image data and obtains the position information of the substrate alignment mark and the mask alignment mark by means of methods such as pattern matching processing. Then, based on the amount of misalignment between the substrate alignment mark and the mask alignment mark, the XY direction in which the substrate S is to be moved, the moving distance, and the rotation angle θ are calculated. Then, the calculated movement amount is converted into the driving amount of a stepping motor, a servo motor, etc. provided in each actuator of the alignment stage 280, and a control signal is generated. Note that two-stage alignment may be performed using a camera for rough alignment with low resolution but a wide field of view and a camera for fine alignment with a narrow field of view but high resolution.

[0034] The control unit 270 is an information processing device that communicates with each component of the film forming apparatus 1 via control lines (not shown) or wireless communication, receives data from each component, and sends signals to each component to control the operation. The control unit 270 can be configured by, for example, a computer having a processor, a memory, a storage, an 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 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, some or all of the functions of the control unit 270 may be configured by a circuit such as an ASIC or an FPGA. Note that the control unit 270 may be provided for each film forming chamber, or one control unit 270 may control a plurality of 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 a conductive wire (not shown). The power supply 290 controls the polarity and magnitude of the applied voltage according to a command from the control unit 270. The power supply 290 can be said to be a voltage supply means. By controlling the polarity and magnitude of the applied voltage (adsorption voltage) to the electrode of the electrostatic chuck C, the adsorption force to the substrate S can be controlled. Note that the power supply 290 and the control unit 270 may be considered to constitute the power supply of the film forming apparatus together.

[0036] Note that the application target of the present invention is not limited to the cluster type film forming apparatus as described above. The present invention can also be applied to an in-line type film forming apparatus in which a plurality of chambers are connected in a vacuum-consistent manner and a substrate held by a substrate carrier is film-formed while moving between the chambers.

[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-like base material made of ceramic or the like. Generally, electrostatic chucks are classified into types such as gradient force type, Coulomb force type, and Johnson-Rahbek force type according to the principle of adsorbing the substrate. In any case, the higher the applied adsorption voltage, the higher the adsorption force can be obtained.

[0038] ​A gradient force type electrostatic chuck adsorbs an object to be adsorbed by utilizing the attractive force generated toward a region having a potential gradient (gradient) generated by the potential difference between electrodes. Since the gradient force is characterized by being generated even when the object to be adsorbed is an insulator, it can hold a bare glass or a glass substrate on which a conductor is not yet formed. When generating the gradient force, an adsorption voltage is applied so that the potential of the first electrode becomes higher than the reference and the potential of the second electrode becomes lower than the reference with respect to the potential of the object to be adsorbed. In order to increase this gradient force, it is necessary to reduce the space between the electrodes and arrange the electrodes densely in order to make the potential gradient as steep as possible. Therefore, as the electrodes used for the gradient force type electrostatic chuck, two comb-tooth electrodes having a structure in which the protruding comb teeth mesh with each other are suitable.

[0039] A Coulomb force type electrostatic chuck adsorbs an object to be adsorbed by the electrostatic attractive force generated by applying voltages of positive and negative potentials to two electrodes, respectively, and is effective when the object to be adsorbed is a conductor. Therefore, it can adsorb effectively if the substrate has an electrode layer of a metal material formed thereon. When the object to be adsorbed is in a floating state not connected to the ground, by opposing both the positive electrode and the negative electrode to the object to be adsorbed, polarization can be generated in the object to be adsorbed and it can be adsorbed. Also, when the object to be adsorbed is grounded, it can be adsorbed by at least one of the positive electrode and the negative electrode. Generally, the Coulomb force is stronger than the gradient force. Also, the larger the area of the electrode facing the object to be adsorbed, the stronger the adsorption force. Therefore, in order to increase the adsorption force, it is necessary to make the ratio of the electrode area to the area of the electrostatic chuck as large as possible.

[0040] The Johnson-Rahbek type electrostatic chuck adsorbs a conductive object to be adsorbed by passing leakage current in the order of a positive electrode, an object to be adsorbed, and a negative electrode, and it is necessary to dispose a dielectric having a volume resistivity value within a predetermined range between the electrode and the object to be adsorbed. The Johnson-Rahbek force is generally stronger than the Coulomb force. Also, in the Johnson-Rahbek type electrostatic chuck, the adsorption force can be increased as the contact area with the object to be adsorbed is increased.

[0041] (Adsorption of moisture to the electrostatic chuck) As described above, since the inside of the film forming apparatus is usually placed in a vacuum atmosphere, there is no unnecessary moisture. However, for example, when the film forming apparatus 1 is opened to the atmosphere during maintenance or the like, the inside of the film forming 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 (especially to the dielectric layer), the adsorption force may decrease and the alignment accuracy may decrease.

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

[0043] FIG. 3(a) 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 base material 255 such as ceramic. The positive electrode 250 and the negative electrode 260 are connected to a power supply 290, and when a voltage is applied under the control of the control unit 270, an adsorption force corresponding to the magnitude of the voltage is generated and the substrate S is adsorbed.

[0044] FIG. 3(b) shows a state where the electrostatic chuck C is not adsorbing moisture or is adsorbing only a trace amount of moisture that does not affect the adsorption force. When a voltage of a predetermined magnitude is applied from the power supply 290, the electrostatic chuck C exhibits an adsorption force (F1) of a desired magnitude corresponding to the voltage and adsorbs the substrate S.

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

[0046] As a preferred manufacturing method of the electrostatic chuck C, there is a method in which after the positive electrode 250, the negative electrode 260, and the wiring portion are installed on a plate-shaped base material by thermal spraying, the base material 255 is completed by thermal spraying ceramic or the like. In such a case, many porous shapes may be formed on the surface portion coated by thermal spraying, and moisture is likely to be adsorbed on that portion. Therefore, the method of the present invention is particularly effective. Note that the electrostatic chuck C may be composed of a plurality of layers. For example, in addition to the layer in which the positive electrode 250 and the negative electrode 260 are embedded, a layer having a temperature control function may be laminated.

[0047] Figure 4 shows a configuration for detecting the level of moisture adsorbed by the electrostatic chuck C in this embodiment. A first switch 320 that can take a connected state and a disconnected state is provided in the wire that supplies power from the power supply 290 to the electrodes of the electrostatic chuck C. Further, the film forming apparatus 1 is provided with a capacitance detection unit 310 connected to both electrodes of the electrostatic chuck C. As the capacitance detection unit 310, a capacitance sensor such as a multimeter that measures the capacitance value between two electrodes and outputs it as an analog signal to the control unit 270 can be used. In such a capacitance sensor, a higher capacitance value is detected as the amount of moisture adsorbed by the electrostatic chuck C increases. A second switch 325 that can take a connected state and a disconnected state is also provided in the wire connecting the capacitance detection unit 310 and the electrostatic chuck C. Each switch can be said to be a switching means.

[0048] The control unit 270 digitally converts the detection signal from the capacitance detection unit 310, compares it with the capacitance value measured in advance and stored in the memory, and determines the presence or absence and degree of moisture adsorption. In this embodiment, the capacitance detection unit 310 corresponds to the measurement means for measuring the capacitance value. Note that the capacitance detection unit 310 and the control unit 270 may be considered together as the measurement means. The measurement means is typically connected to the electrical path between the power supply and the electrodes. Further, the control unit 270 can be considered as the detection means for detecting the level of adsorbed moisture based on the measured capacitance value.

[0049] Further, a notification unit 275 may be provided in the film forming apparatus 1 to notify the user of the moisture adsorption state by the electrostatic chuck C in response to an instruction from the control unit 270. The configuration of the notification unit 275 is not limited as long as it can notify the user of information. For example, when the control unit 270 is a computer, the monitor or speaker of the computer may be used, or a dedicated lamp or speaker for notifying foreign matter attachment may be arranged. When the control unit 270 detects an abnormal state to be notified regarding the electrostatic chuck C, it notifies the user via the notification unit 275. The notification unit 275 may further notify the amount of moisture and the time required for moisture removal. Alternatively, the control unit 270 may determine whether the substrate S can be adsorbed by the electrostatic chuck C. Based on the determination result, the control unit 270 may start the adsorption of the substrate S by the electrostatic chuck C in the next film formation process. Alternatively, the control unit 270 may determine the time until the adsorption by the electrostatic chuck C becomes possible.

[0050] Further, when a state such as a large amount of moisture is detected, the control unit 270 may increase the set value of the adsorption voltage applied at the next film formation instead of or together with the notification by the notification unit 275 so that the substrate S is surely adsorbed. Specifically, when the capacitance detection value is higher than a predetermined value or when the amount of moisture obtained from the detection value is larger than a predetermined amount, the set value of the adsorption voltage is increased.

[0051] The capacitance detection unit 310 of the present embodiment does not apply a voltage from the power supply 290, and thus detects the capacitance in a state where the substrate S is not adsorbed. Further, by providing the first switch 320 and the second switch 325 as shown in the figure, the path can be surely switched between the voltage application time and the capacitance detection time. That is, at the time of capacitance detection, the first switch 320 is in the open state and the second switch 325 is in the connected state (first state). Also, at the time of voltage application, the first switch 320 is in the connected state and the second switch 325 is in the open state (second state). As a result, it is not necessary to use a device corresponding to a high voltage as the capacitance detection unit 310, and the configuration can be simplified.

[0052] The state detection of the electrostatic chuck C in the present embodiment is preferably performed at a timing when the substrate S is not adsorbed. Examples of the timing include when the film forming apparatus is installed, after a predetermined number of substrates are formed, after the apparatus operates for a predetermined time, during regular or temporary maintenance, and the like.

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

[0054] In this embodiment, it is assumed that the inside of the film forming apparatus is evacuated to dry the electrostatic chuck C and remove the adsorbed moisture. After the start of the graph, evacuation is started at time T1. Thereafter, as the level of the moisture content 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 is sufficiently dried to the extent that it can exhibit the adsorption force required for adsorbing the substrate S. Therefore, the period from time T1 to time T2 (Term1) is the drying period (moisture removal period), and it can be said that the period after time T2 (Term2) is the adsorption possible period.

[0055] Note that the capacitance value, the corresponding moisture content, time, etc. shown in FIG. 5 are examples, and should be appropriately changed according to the material and configuration of the electrostatic chuck C, the required adsorption force, etc. For example, the capacitance value changes according to the electrode arrangement pattern of the electrostatic chuck C, the thickness of the electrode, the thickness and dielectric constant of the dielectric layer, the type of impregnating agent of the material, the dimensions of the electrostatic chuck C, etc. Also, the change in the capacitance value due to evacuation changes according to 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, or the determination made from the detected value It may notify the level of moisture, or may notify the remaining time of drying at any time. It may also simply notify whether adsorption is possible or not. Further, the stage at which the notification is made can be arbitrarily set. Furthermore, instead of or together with the notification to the user, the detected value and the information based thereon may be used for subsequent control by the control unit 270. Examples of the subsequent control include the start of the film forming process.

[0057] As described above, according to this embodiment, since the state of the moisture adsorbed on the electrostatic chuck C can be detected based on the detected value of the capacitance, it is possible to prompt appropriate actions by the user, such as moisture removal from the electrostatic chuck C by vacuum drying. Therefore, film formation is not performed in a state where the adsorption force of the electrostatic chuck C has decreased, enabling accurate film formation and suppressing the lengthening of the tact time.

[0058] <Example 2> Subsequently, Example 2 of the present invention will be described. The same components as those in Example 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0059] As shown in FIG. 6, in the film forming apparatus 1 of the present invention, a temperature control member 300 for adjusting the temperature of the electrostatic chuck C can be arranged. Typically, the temperature control member 300 is arranged to be in contact with the electrostatic chuck C as shown in the drawing. The temperature control member 300 may be configured such that, for example, a pipe through which a fluid such as water or oil can pass is arranged inside a plate-like base material that is in contact with the electrostatic chuck C. The temperature control member 300 adjusts the temperature of the electrostatic chuck C by receiving the supply of a fluid whose temperature has been adjusted from an external fluid supply unit. The temperature adjustment in this embodiment includes a heat treatment for heating the electrostatic chuck C to evaporate moisture at a timing such as after atmospheric open maintenance. Further, the temperature adjustment may include a cooling treatment for cooling the electrostatic chuck C during film formation to suppress the temperature rise and prevent the alteration and deterioration of the organic material.

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

[0061] According to the configuration of this embodiment, the moisture adsorbed on the electrostatic chuck C can be removed more quickly. Therefore, it is possible to further shorten the tact time. In addition, providing 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, so moisture can be removed while suppressing an increase in cost by using existing members.

[0062] <Example 3> Subsequently, Example 3 of the present invention will be described. The same components as those in Examples 1 and 2 are denoted by the same reference numerals, and the description thereof will be omitted.

[0063] FIG. 7 shows a configuration for detecting moisture adsorbed on the electrostatic chuck C in this embodiment. The capacitance detection unit 310 of this embodiment is provided between the power supply 290 and the electrostatic chuck C. The capacitance detection unit 310 of this embodiment has the same function of measuring the capacitance value between both electrodes and outputting it to the control unit 270 as in Example 1, but there is a possibility of performing capacitance measurement even while the adsorption voltage from the power supply 290 is being applied. Therefore, the capacitance detection unit 310 of this embodiment is required to have performance corresponding to the passage of a high voltage.

[0064] Also in this embodiment, as in Examples 1 and 2, the higher the amount of moisture adsorbed by the electrostatic chuck C, the higher the detected capacitance value. Therefore, the water content status of the electrostatic chuck C can be notified to the user. In particular, in this embodiment, since the capacitance value can be constantly monitored under the same conditions as when the actual substrate S is adsorbed, detection processing under the same conditions as during actual use is possible.

[0065] <Method for manufacturing an 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. Hereinafter, the configuration of an organic EL display device will be shown as an example of an electronic device, and a method for manufacturing the organic EL display device will be exemplified.

[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 a cross-sectional structure of one pixel.

[0067] As shown in FIG. 8(a), in the display area 701 of the organic EL display device 700, a plurality of pixels 702 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 smallest unit capable of displaying a desired color in the display area 701. In the case of the organic EL display device according to this embodiment, the pixel 702 is constituted by a combination of a first light-emitting element 702R, a second light-emitting element 702G, and a third light-emitting element 702B that exhibit different emissions. The pixel 702 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 constituted by 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.

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

[0069] Further, 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 commonly for a plurality of light-emitting elements 702R, 702G, and 702B, or may be formed for each light-emitting element. In order to prevent the first electrode 704 and the second electrode 708 from being short-circuited by foreign matter, an insulating layer 709 is provided between the first electrodes 704. Further, since the organic EL layer deteriorates due to moisture and oxygen, a protective layer 710 for protecting the organic EL element from moisture and oxygen is provided.

[0070] In FIG. 8(b), the hole transport layer 705 and the electron transport layer 707 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. Further, a hole injection layer having an energy band structure capable of smoothing 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 also 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 substrate (mother glass) 703 on which a circuit (not shown) for driving the organic EL display device and the first electrode 704 are formed is prepared.

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

[0074] The substrate 703 with the patterned insulating layer 709 is placed on a substrate carrier on which an adhesive member is disposed. The substrate 703 is held by the adhesive member. It is carried into the first organic material film-forming apparatus, and after inversion, the hole transport layer 705 is formed as a common layer on the first electrode 704 in the display region. The hole transport layer 705 is formed by vacuum evaporation. Actually, since the hole transport layer 705 is formed in a size larger than that of the display region 701, a high-definition mask is not required.

[0075] Next, the substrate 703 on which the hole transport layer 705 has been formed is carried into the second organic material film-forming apparatus. Alignment between the substrate and the mask is performed, the substrate is placed on the mask, and the light-emitting layer 706R that emits red light is formed on the portion where the red light-emitting element of the substrate 703 is disposed.

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

[0077] The substrate on which the electron transport layer 707 has been formed is moved to a metallic vapor deposition material film-forming apparatus to form the second electrode 708.

[0078] Thereafter, it is moved to a plasma CVD apparatus to form the protective layer 710, completing the film-forming process on the substrate 703. After inversion, the adhesive member is peeled off from the substrate 703 to separate the substrate 703 from the substrate carrier. Thereafter, through cutting, the organic EL display device 700 is completed.

[0079] After the substrate 703 with the patterned insulating layer 709 is carried into the film forming apparatus until the film formation of the protective layer 710 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 embodiment, 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

[0080] 1: Film forming apparatus, 270: Control unit, 310: Capacitance detection unit, C: Electrostatic chuck, S: Substrate

Claims

1. A film forming apparatus for forming a film on a substrate, comprising an adsorption surface, a first electrode, and a second electrode, and an electrostatic chuck that adsorbs the substrate by the adsorption surface when a voltage is applied to the first electrode and the second electrode, measuring means for measuring a value of a capacitance between the first electrode and the second electrode, detection means for detecting a level of adsorbed water adsorbed on the electrostatic chuck based on the value of the capacitance, and characterized by comprising the above.

2. The detection means detects the level of the adsorbed water based on a temporal change in the value of the capacitance. The film forming apparatus according to claim 1, characterized by the above.

3. The detection means determines whether the substrate can be adsorbed by the electrostatic chuck based on the detected level of the adsorbed water. The film forming apparatus according to claim 1 or 2, characterized by the above.

4. After the detection means determines that the substrate can be adsorbed by the electrostatic chuck, adsorption for film formation on the substrate is started. The film forming apparatus according to claim 3, characterized by the above.

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

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

7. It is possible to remove the adsorbed water from the electrostatic chuck by vacuum exhaust. The film forming apparatus according to claim 1 or 2, characterized by the above.

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

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

10. The first electrode and the second electrode are provided with switching means for switching between a first state in which they 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, the first electrode, and the second electrode is interrupted. The film forming apparatus according to claim 9, characterized by the above.

11. The measurement means is connected to an electrical path between the first electrode and the second electrode and the voltage supply means. The film forming apparatus according to claim 9, characterized in that.

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

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