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

Abstract

To provide a film forming apparatus, a film forming method, and a method for manufacturing an electronic device capable of suppressing adverse effects on a substrate when the substrate is attracted by an electrostatic chuck.SOLUTION: An electrostatic chuck C includes a first portion 242 that adsorbs a peripheral region of a substrate S and a second portion 244 that adsorbs the central region of the substrate S. The number of electrodes per unit length of the first portion 242 is greater than the number of electrodes per unit length of the second portion 244. The ratio of the electrode width to the inter-electrode space in the second portion 244 is greater than the ratio of the electrode width to the inter-electrode space in the first portion 242. After applying a voltage to the electrode of the second portion 244 to adsorb the substrate S, a voltage is applied to the electrode of the first portion 242 to adsorb the substrate S.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Conventionally, a film formation apparatus equipped with an electrostatic chuck that attracts and holds a substrate by electrostatic force has been known. That is, in such a film formation apparatus, the electrostatic chuck is used to hold a substrate during film formation or when measuring the thickness of a thin film formed on the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-099912 [Patent Document 2] Japanese Patent Publication No. 2023-79032 Summary of the Invention [Problem to be solved by the invention]

[0004] When a substrate is supported at its periphery, its central portion deforms and sags due to its own weight, which raises concerns about the impact on the substrate when it is attached to the electrostatic chuck.

[0005] An object of the present invention is to provide a film deposition apparatus, a film deposition method, and a method for manufacturing an electronic device that can suppress adverse effects on a substrate when the substrate is attracted by an electrostatic chuck. [Means for solving the problem]

[0006] The film forming apparatus of the present invention comprises: A film forming apparatus including an electrostatic chuck that attracts and holds a substrate by electrostatic force, the electrostatic chuck includes a first portion that attracts a peripheral region of the substrate and a second portion that attracts a central region of the substrate; the number of electrodes per unit length of the first portion is greater than the number of electrodes per unit length of the second portion; a ratio of the width of the electrodes to the inter-electrode space in the second portion is greater than a ratio of the width of the electrodes to the inter-electrode space in the first portion; The method is characterized in that after a voltage is applied to the electrode of the second portion to attract the substrate, a voltage is applied to the electrode of the first portion to attract the substrate. [Effects of the Invention]

[0007] According to the present invention, adverse effects on the substrate and the like can be suppressed when the substrate is attracted by the electrostatic chuck. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic plan view showing the configuration of a film forming apparatus. [Figure 2] FIG. 2 is a schematic view showing the internal configuration of a film formation chamber. [Figure 3] FIG. [Figure 4] FIG. 2 is a plan view showing the configuration of an electrostatic chuck and the arrangement of electrodes. [Figure 5] 1 is a schematic diagram showing the configuration of an electrostatic chuck and the arrangement of electrodes. [Figure 6] Schematic diagram showing the line / space ratio of the electrodes of an electrostatic chuck. [Figure 7] 4 is a graph showing a procedure for applying a voltage to an electrostatic chuck. [Figure 8] 10A and 10B are diagrams showing an electrostatic check and a state of a substrate when a voltage is applied to an electrostatic chuck. [Figure 9] FIG. 2 is a diagram showing a specific example of a detection unit that detects whether or not a substrate is attracted to an electrostatic chuck. [Figure 10] 4 is a graph showing a procedure for applying a voltage to an electrostatic chuck. [Figure 11] 4 is a graph showing a procedure for applying a voltage to an electrostatic chuck. [Figure 12] 4 is a graph showing a procedure for applying a voltage to an electrostatic chuck. [Figure 13] FIG. 1 is a diagram illustrating a configuration of an electronic device. [Figure 14] Schematic diagram of a film thickness measuring device. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes in detail, by way of example, the mode for carrying out the present invention with reference to the drawings. However, the following examples merely exemplify preferred configurations of the present invention, and the scope of the present invention is not limited to these configurations. Furthermore, the hardware and software configurations, processing flows, manufacturing conditions, dimensions, materials, shapes, and the like of the apparatus in the following description are not intended to limit the scope of the present invention unless otherwise specified.

[0010] The present invention is preferably applicable to a film formation apparatus that forms a thin film of a film material on the surface of a substrate by vapor deposition or sputtering. The present invention is preferably applicable to a film formation apparatus that forms a thin film of a desired pattern on the surface of a substrate through a mask. Any substrate material can be used, such as glass, resin, metal, or silicon. Any film formation material can be used, such as organic materials 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.

[0011] (Example) A film deposition apparatus and a film deposition method according to an embodiment of the present invention will be described with reference to FIGS.

[0012] <Film forming equipment> 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 organic EL displays, 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.

[0013] The film formation apparatus 1 includes a transfer chamber 130 located in the center, and multiple film formation chambers 110 (110a to 110d) and mask stock chambers 120 (120a, 120b) located around the transfer chamber 130. The film formation chamber 110 is a chamber where film formation processing is performed on a substrate 10. 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 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 mask M attached to an articulated arm.

[0014] 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.

[0015] The film forming apparatus 1 shown in FIG. 1 constitutes one film forming cluster, and other film forming apparatuses are provided on the upstream and downstream sides. A film formation cluster can be connected. A swirl chamber 170 that changes the direction of the substrate 10 is provided further upstream of the pass chamber 150 and further downstream of 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.

[0016] The film formation materials in the multiple film formation chambers 110a-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 placed in each of the film formation chambers 110a-110d, and a layered structure may be formed as the substrate S moves sequentially through the film formation chambers 110a-110d. Alternatively, film formation sources of the same film formation material may be placed in the film formation chambers 110a-110d, allowing film formation to be performed on multiple substrates S in parallel. Alternatively, a first film formation material may be placed in the film formation chambers 110a and 110c, and a second film formation material may be placed in the film formation chambers 110b and 110d, and the first layer may be formed in the film formation chamber 110a or 110c, followed by control to form the second layer in the film formation chamber 110b or 110d.

[0017] The electrostatic chuck of this embodiment can more effectively adsorb a substrate when a conductor is attached to a specific region of the substrate. Specifically, 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), adsorption by a relatively strong Coulomb force becomes possible. Therefore, it is effective to install the electrostatic chuck of this embodiment in a deposition chamber to which the substrate is transferred after the electrode layer has been deposited. For example, if an electrode layer has been deposited on a substrate in deposition chamber 110a and organic layers are subsequently deposited in deposition chambers 110b-110d, the electrostatic chuck of this embodiment can be placed in deposition chambers 110b-110d. However, since the electrostatic chuck of this embodiment also utilizes a gradient force that can adsorb even insulators, it is possible to adsorb substrates on which an electrode layer has not yet been deposited, such as bare glass.

[0018] <Film formation chamber> 2 is a cross-sectional schematic diagram 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 transferring the substrate S to and from the transfer robot 140, aligning the substrate S to adjust the relative positional relationship between the substrate S and the mask M, fixing the substrate S on the mask, and film formation. In the following explanation, an XYZ Cartesian coordinate system is used, with the vertical direction being the Z direction. The rotation angle around the Z axis is represented by θ.

[0019] The film formation chamber 110 has a vacuum chamber 200. The interior of the vacuum chamber 200 is maintained in a vacuum atmosphere or an inert gas atmosphere such as nitrogen gas. Inside the vacuum chamber 200, an electrostatic chuck C, a substrate support 210, a mask table 221, and an evaporation source 240 (film formation source) are provided.

[0020] 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 can be used as the mask M. The mask M is placed on a mask table 221. In the configuration of this embodiment, the film is formed after the substrate S is positioned and placed on the mask.

[0021] The substrate support part 210 has a plurality of claw-shaped supports for receiving the substrate S transferred into the film formation chamber. The electrostatic chuck C is a substrate holding means inside the film formation chamber, and uses electrostatic force to attract and hold the substrate S supported by the substrate support part 210. The electrostatic chuck C comes into contact with the surface of the substrate S opposite to the film formation surface.

[0022] A cooling member may be provided inside or on top of the electrostatic chuck C to suppress the temperature rise of the substrate S during film formation and prevent the organic material from changing or deteriorating. The substrate support part 210 may also have a pressing tool corresponding to the support tool. The support tool and the pressing tool clamp the edge of the substrate S. Therefore, the substrate S can be held by the substrate support part 210 in addition to the electrostatic chuck C, which makes the substrate S more stable. Also, a magnet for attracting the mask M may be disposed above the electrostatic chuck C.

[0023] 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. For example, a sputtering device using a sputtering target may also be used. In this embodiment, the evaporation source 240 is disposed vertically below the substrate S, and a thin film is formed on the lower surface of the substrate S.

[0024] An electrostatic chuck actuator 252 and an alignment stage 280 are provided at the upper outside of the vacuum 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, etc.

[0025] When the electrostatic chuck C holds the substrate S loaded into the film formation chamber, the electrostatic chuck actuator 252 first lowers the electrostatic chuck C so that the electrostatic chuck C abuts or approaches sufficiently close to the substrate S supported by the substrate support 210. The control unit 270 then controls the power supply 290 to apply a predetermined attraction voltage to the electrode embedded in the electrostatic chuck C. This causes the electrostatic chuck C to hold the substrate S. Subsequently, during alignment, the electrostatic chuck actuator 252 further lowers the electrostatic chuck C to bring the substrate S closer to the mask M. The alignment stage 280 then performs alignment. Subsequently, during film formation, the evaporation source 240 releases the film formation material. Upon completion of film formation, the electrostatic chuck actuator 252 raises the electrostatic chuck C and transfers the substrate S on which the film has been formed to a transfer robot. The voltage applied to the electrostatic chuck C is then set to a predetermined release voltage (e.g., 0 V), thereby releasing the substrate from the electrostatic chuck C.

[0026] 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 vacuum chamber 200, an actuator part 282 for X, Y, and θ movement, and a connection part 283 that is connected to the electrostatic chuck C.

[0027] 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 the positions of both the substrate 10 and the mask 220, as long as the substrate S and the mask M can be aligned relative to each other.

[0028] A camera 261 that performs optical imaging and generates image data is provided at the upper outside of the vacuum chamber 200. The camera 261 captures images through a vacuum sealing window provided in the vacuum chamber 200. In this embodiment, multiple 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.

[0029] 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. 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 drive amounts for the stepping motors, servo motors, etc., provided in each actuator of the alignment stage 280, and a control signal is generated. Two-stage alignment may be performed by disposing 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 in the film formation chamber 110.

[0030] 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 programmable logic controller (PLC). 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.

[0031] 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. By controlling the polarity and magnitude of the voltage applied to the electrostatic chuck C, the chucking force for the substrate S can be controlled.

[0032] The application of the film formation apparatus of this embodiment 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.

[0033] <Electrostatic chuck> Electrostatic chuck C has a structure in which an electric circuit such as a metal electrode is embedded in a plate-shaped substrate made of ceramic or the like. Generally, electrostatic chucks are divided into gradient force type and Coulomb force type depending on the principle of how they attract the substrate. There are also other electrostatic chucks that use the Johnsen-Rahbek force.

[0034] Gradient force-type electrostatic chucks attract objects by using an attractive force generated toward a region with a potential gradient (gradient) due to the potential difference between electrodes. Gradient force is generated even when the object is an insulator, making it possible to hold even plain glass or glass substrates without conductive coatings. To generate the gradient force, a clamping 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 maximize 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-tooth electrodes with interdigitated protruding teeth are ideal for use in gradient force-type electrostatic chucks.

[0035] The Coulomb force type electrostatic chuck attracts an object by electrostatic attraction generated by applying a positive potential and a negative potential voltage to two electrodes, respectively. This is effective when the object to be attracted is an electrically conductive material. When the object to be attracted is in a floating state (not connected to ground), polarization is generated in the object to be attracted by facing both the positive electrode and the negative electrode to the object to be attracted, thereby enabling attraction. Furthermore, when the object to be attracted is grounded, the object can be attracted by at least one of the positive electrode and the negative electrode. In a Coulomb force-type electrostatic chuck, the larger the area of ​​the electrode facing the object to be attracted, the stronger the attraction force. Therefore, to increase the attraction force, it is necessary to maximize the ratio of the electrode area to the area of ​​the electrostatic chuck.

[0036] Generally, Coulomb force-type electrostatic chucks have a stronger clamping force than gradient force-type chucks. Therefore, when the object to be clamped is a conductive material, a Coulomb force-type electrostatic chuck can hold the substrate more stably. For example, a gradient force-type electrostatic chuck is required when the substrate is bare glass or when no conductive film is formed on it. However, if the substrate is formed with a conductive film, such as a metal electrode film, a Coulomb force-type electrostatic chuck can provide a stronger clamping force.

[0037] The structure and function of the electrostatic chuck C of this embodiment will be described with reference to the drawings. FIG. 3(a) is a plan view of a substrate S, which is an object to be attracted, and FIG. 3(b) is a plan view of a mask M. FIGS. 3(a) and 3(b) are plan views of the substrate S and the mask M viewed from below in the Z direction inside the film formation chamber 110. The substrate S shown in FIG. 3(a) is divided into a first region 12 (peripheral region of the substrate) outside the element formation area indicated by the dashed line, and a second region 14 (central region of the substrate) inside the dashed line. Note that the dashed line is for convenience's sake; the material of the substrate S is the same both inside and outside the dashed line. The second region 14 is a region where at least one conductive film (e.g., a metal film constituting an electrode layer) of multiple films formed on the substrate S is formed. More typically, the second region 14 is a film formation region where an organic EL element is formed. The first region 12 is a region outside the second region 14. Therefore, at least one conductive film layer is present in the second region 14, but the first region 12 is in a state where no conductive film is present or where the proportion of the conductive film is lower than that in the second region 14.

[0038] 3(b) has a structure in which a metal mask foil 226 is stretched over a frame 222. The frame 222 may be provided with crosspieces 224 to strengthen the structure or to divide the area. When the substrate S is placed on the mask M, the area where the metal mask foil 226 is provided faces the second area 14 of the substrate S. With the substrate S placed on the mask M, a film forming material is ejected upward in the Z direction from an evaporation source 240, forming a film on the surface of the substrate.

[0039] It is not necessary that the areas of the film formation regions of all layers stacked on the substrate S are the same. Therefore, a conductive film may be formed in a part of the first region 12, and there may be a part of the second region 14 where no conductive film is formed. Even in this case, as long as the ratio of the conductive film formed in the second region 14 is higher than the ratio of the conductive film formed in the first region 12, it is suitable for chucking using the electrostatic chuck C of this embodiment.

[0040] FIG. 4 is a plan view of an electrostatic chuck C, showing the electrodes embedded therein in a transparent manner. Electrodes 250a to 250h are disposed in the electrostatic chuck C. Power supplies 290a to 290d are connected to the electrodes 250a to 250h, as indicated by the dashed arrows. The power supplies are connected via power supply terminals disposed on the outer edge of the electrostatic chuck C. Specifically, power supply 290a controls the voltage applied to electrodes 250a and 250b, which are interdigitated comb electrodes. Power supply 290b controls the voltage applied to electrodes 250c and 250d, which have relatively large areas. Power supply 290c controls the voltage applied to electrodes 250e and 250f, which are interdigitated comb electrodes. Power supply 290d controls the voltage applied to electrodes 250g and 250h, which have relatively large areas.

[0041] 4, the inner rectangle indicates a second portion 244 of the electrostatic chuck C. The portion between the inner rectangle and the outer rectangle indicates a first portion 242 of the electrostatic chuck C. While the electrostatic chuck C holds the substrate S, the first portion 242 faces the first region 12 of the substrate S, and the second portion 244 faces the second region 14 of the substrate S.

[0042] 4, the first portion 242 and the second portion 244 are each divided into left and right halves, and an electrode is arranged in each divided region. However, the arrangement of the electrodes is not limited to the illustrated example, and the presence or absence of division and the number of divisions can be determined as appropriate. The effects of this embodiment can be obtained as long as there is at least a configuration including interdigitated comb electrodes arranged in the first portion 242, a voltage supply unit that supplies voltage to each of the comb electrodes, two large-area electrodes arranged in the second portion 244, and a voltage supply unit that supplies voltage to each of the two electrodes independently of the voltage supply unit for the comb electrodes.

[0043] FIG. 5(a) is a cross-sectional view of the electrostatic chuck C taken along line A-A' in FIG. 4. FIG. 5(b) is a conceptual cross-sectional view illustrating the correspondence between each portion of the electrostatic chuck C and each region of the substrate S. As shown in the figure, the electrodes are denser in the first portion 242 of the electrostatic chuck C than in the second portion 244. That is, the number of electrodes per unit length in the first portion 242 of the electrostatic chuck C is greater than the number of electrodes per unit length in the second portion 244. As a result, the electrodes are densely arranged in the first portion 242, the potential gradient is steeper, and the gradient force is therefore stronger. As a result, the chucking force using the gradient force is stronger. Therefore, in the chucking force acting from the electrostatic chuck C to the substrate S, the gradient force component due to the first portion 242 is greater than the gradient force component due to the second portion 244. This allows the electrostatic force due to the gradient force to act even on the first region 12 of the substrate S where no conductive film is formed (or where the proportion of the conductive film is low).

[0044] When the electrodes are comb-tooth electrodes, the number of electrodes per unit length varies depending on the cross section of the electrostatic chuck C. In FIG. 5(a), the direction in which the teeth of the comb extend is defined as a first direction, and the direction in which the teeth of the comb are arranged, intersecting the first direction (typically perpendicular), is defined as a second direction. Here, if the first portion 242 is divided into multiple regions, the direction in which the teeth of the comb electrode extend may differ from region to region. Even in such a case, it is sufficient to view the cross section in the direction in which the teeth of the comb are arranged for each region.

[0045] Figure 6(a) is an enlarged view of a portion of the first portion 242 in Figure 5(a). In Figure 6(a), the width (line: L) of the electrodes 250a and 250b is 1 mm, and the width (space: S) of the space between the electrodes 250a and 250b is 1.5 mm. Therefore, in the first portion 242, the ratio of the electrode width to the width of the inter-electrode space (line / space ratio: L / S ratio) is 1 / 1.5.

[0046] 6(b) is an enlarged view of a portion of the second portion 244 in FIG. 5(a). In FIG. 6(b), the widths (L) of the electrodes 250c and 250d are each 9 mm, and the width (S) of the space between the electrodes 250c and 250d is 1.5 mm. Therefore, the L / S ratio in the second portion 244 is 9 / 1.5. That is, the electrostatic chuck C is configured so that the L / S ratio of the second portion 244 is larger than that of the first portion 242. This results in a larger ratio of the electrode area to the area of ​​the electrostatic chuck C in the second portion 244 than in the first portion 242. Therefore, in the chucking force acting on the substrate S from the electrostatic chuck C, the Coulomb force component due to the second portion 244 is larger than the Coulomb force component due to the first portion 242. This allows a strong chucking force using Coulomb force to be exerted on the second region 14 of the substrate S on which a conductive film is formed (or on which the proportion of the conductive film is high). As a result, a strong suction force is exerted even at the center of the substrate, which tends to sag, and the substrate S can be held in a good condition.

[0047] As described above, in this embodiment, the electrode configuration of the electrostatic chuck C is varied depending on whether the region of the substrate S is a region where an organic EL element is formed, thereby making it possible to stably hold the substrate.

[0048] <Adsorption procedure> 7 to 9, a procedure for attracting a substrate S by the electrostatic chuck C in the film formation apparatus 1 according to this embodiment will be described. As described above, when attracting and holding a substrate S by the electrostatic chuck C, the electrostatic chuck actuator 252 lowers the electrostatic chuck C so that the electrostatic chuck C abuts or approaches sufficiently close to the substrate S supported by the substrate support part 210. 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. In this embodiment, a voltage is first applied to the electrode of the second part 244 of the electrostatic chuck C to attract the substrate S (first step). Then, after the substrate S is attracted to the second part 244 in the first step, a voltage is applied to the electrode of the first part 242 to attract the substrate S (second step). 7 is a graph in which the horizontal axis represents the elapsed time and the vertical axis represents the voltage applied to the electrostatic chuck C, with the solid line representing the voltage applied to the electrode of the second portion 244 and the dotted line representing the voltage applied to the electrode of the first portion 242. Also, FIG. 8(a) shows the state immediately before a voltage is applied to the second portion 244, (b) shows the state immediately before a voltage is applied to the electrode of the first portion 242, and (c) shows the state in which the substrate S is attracted and held by the electrostatic chuck C.

[0049] As shown in the graph of FIG. 7, in this embodiment, the maximum voltage applied to the electrode of the second portion 244 in the first step is controlled to be smaller than the maximum voltage applied to the electrode of the first portion 242 in the second step.

[0050] The film forming apparatus 1 according to this embodiment is provided with a detection means for detecting whether or not the substrate S is attracted to the electrostatic chuck C. Various known techniques can be adopted for such a detection means, but three specific examples will be described here with reference to FIG.

[0051] FIG. 9( a) shows an example in which a distance detection sensor is used as the detection means. A method for detecting whether or not a substrate S is attracted using a distance detection sensor is disclosed, for example, in Japanese Patent Application Laid-Open No. 2022-33147, and will be briefly described here. As shown in the figure, a first sensor Se1 for detecting whether or not a substrate S is attracted near the center and a second sensor Se2 for detecting whether or not a substrate S is attracted near the periphery are provided below the substrate S. These sensors are configured as laser displacement meters serving as distance detection sensors capable of detecting the distance between the substrate S and the attracting surface of the electrostatic chuck C. This laser displacement meter irradiates laser light onto the lower surface (attracting surface) of the electrostatic chuck C and the opposing upper surface of the substrate S, respectively, and can measure the distance between the attracting surface of the electrostatic chuck C and the upper surface of the substrate S based on the light reflected from these surfaces. This makes it possible to detect whether or not the substrate S is attracted to the electrostatic chuck C.

[0052] FIG. 9(b) shows an example in which a capacitance sensor is used as the detection means. A method for detecting the presence or absence of adhesion using a capacitance sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 2022-33147, and will be briefly described here. As shown in the figure, the electrostatic chuck C is provided with a first sensor Se3 for detecting the presence or absence of adhesion near the center of the substrate S, and a second sensor Se4 for detecting the presence or absence of adhesion near the periphery of the substrate S. These sensors are composed of capacitance sensors whose capacitance changes depending on the distance from the substrate S. The capacitance sensor is a capacitor that faces the substrate S. The electrostatic chuck C is composed of an electrode part that forms one of the electrodes, and a detection output part that detects and outputs a change in the electrostatic capacitance between this electrode part and the substrate S, and the electrode part is embedded in the attracting surface of the electrostatic chuck C so that it faces the substrate S. When the distance between the substrate S and the attracting surface of the electrostatic chuck C changes, the electrostatic capacitance detected by the capacitance sensor also changes, making it possible to detect whether the substrate S has been attracted to the electrostatic chuck C.

[0053] FIG. 9(c) shows an example in which the presence or absence of adhesion is detected based on the capacitance between the electrostatic chuck C and the substrate S without using a sensor as the detection means. Such a method is disclosed, for example, in Japanese Patent Application Laid-Open No. 2022-155113, and will be briefly described here. As shown in the figure, a detection unit 275 is provided, electrically connected to the electrode of the electrostatic chuck C and a power supply 290. The control unit 270 determines the adhesion state of the substrate S by the electrostatic chuck C based on the measurement results of the detection unit 275. When the voltage applied to the electrode by the power supply 290 is constant, the capacitance between the electrode and the substrate S changes depending on the distance between the electrode and the conductive film pattern formed on the substrate S. This makes it possible to detect whether the substrate S is attracted to the electrostatic chuck C. Note that the detection means may also be a touch-type sensor or other means for mechanically detecting the presence or absence of adhesion (see, for example, Japanese Patent Application Laid-Open No. 2022-57674).

[0054] In this embodiment, the control unit 270 gradually increases the voltage applied to the electrode of the second portion 244 in the first step, and stops increasing the voltage when the detection means detects that the substrate S has been attracted to the electrostatic chuck C. FIG. 7 shows an example in which the voltage increase is stopped at time 2. In the second step, the control unit 270 gradually increases the voltage applied to the electrode of the first portion 242, and stops increasing the voltage when the detection means detects that the substrate S has been attracted to the electrostatic chuck C. FIG. 7 shows an example in which the voltage increase is stopped at time 3.5.

[0055] In this embodiment, after applying voltage to the electrodes of the first portion 242 and the second portion 244, the control unit 270 detects by the detection unit that the substrate S has been attracted to the electrostatic chuck C in both the first portion 242 and the second portion 244, and then reduces the voltage applied to the electrodes of the first portion 242 and the second portion 244 within a range that allows the substrate S to be attracted to the electrostatic chuck C. Note that FIG. 7 shows an example in which it is detected at time 3.5 that the substrate S has been attracted to the electrostatic chuck C in both the first portion 242 and the second portion 244, and then a time lag is provided until time 4. However, the applied voltage may be reduced at time 3.5.

[0056] After the substrate S is held on the electrostatic chuck C, a predetermined process is performed, and after the process is completed, the applied voltage is reduced to a voltage (0 V in the example of FIG. 7) at which the substrate S can be peeled off from the electrostatic chuck C. In this embodiment, an alignment operation and a film formation operation are performed in the film formation chamber 110 from time 4 to time N in FIG.

[0057] <Advantages of the film forming apparatus and film forming method according to this embodiment> In this embodiment, when the substrate S is attracted to the electrostatic chuck C, a voltage is applied to the electrode of the second portion 244 to attract the substrate S, and then a voltage is applied to the electrode of the first portion 242 to attract the substrate S. This reduces the stress acting on the substrate S during the attracting operation, and can suppress adverse effects on the substrate S. This point will be explained below. Generally, a voltage is applied uniformly and simultaneously to all of the electrodes provided in the electrostatic chuck. In this case, since the central portion of the substrate before attracting is deformed so that it sags due to its own weight, the center of the substrate is attracted to the electrostatic chuck after the periphery of the substrate is attracted to the electrostatic chuck. As a result, when the center of the substrate is attracted to the electrostatic chuck while the periphery of the substrate is attracted to the electrostatic chuck, the substrate tries to return to a flat shape, and the peripheral portion attracted to the electrostatic chuck is pulled back. Compressive stress occurs in the substrate S between the near and central regions. This can have adverse effects on the substrate. In contrast, according to this embodiment, the central region (second region 14) of the substrate S is attracted to the electrostatic chuck C first, and then the peripheral region (first region 12) of the substrate S is attracted. This makes it possible to prevent compressive stress from acting on the substrate S.

[0058] Note that, in order to obtain the above-described effects, it is not necessarily necessary to perform control such as the example shown in Fig. 7. Other examples will be described below with reference to Figs. 10 to 12. All of these are graphs in which the horizontal axis represents the elapsed time and the vertical axis represents the voltage applied to the electrostatic chuck C, with the solid line representing the voltage applied to the electrode of the second portion 244 and the dotted line representing the voltage applied to the electrode of the first portion 242.

[0059] 10(a) shows an example in which a voltage capable of attracting the substrate S is applied to the electrode of the second portion 244 (first step), and then a voltage capable of attracting the substrate S is applied to the electrode of the first portion 242 (second step). In this example, the maximum voltage applied to the electrode of the second portion 244 in the first step is controlled to be equal to the maximum voltage applied to the electrode of the first portion 242 in the second step. Even in this case, the above-described operational effects can be obtained.

[0060] 10(b) shows an example in which a voltage capable of attracting the substrate S is applied to the electrode of the second portion 244 (first step), and then a voltage capable of attracting the substrate S is applied to the electrode of the first portion 242 (second step). In this example, the maximum voltage applied to the electrode of the second portion 244 in the first step is controlled to be smaller than the maximum voltage applied to the electrode of the first portion 242 in the second step. Even in this case, the above-mentioned effects can be obtained.

[0061] 11(a) shows an example of voltage control as follows. That is, in a first step, the voltage applied to the electrode of the second portion 244 is gradually increased, and the voltage increase is stopped when the detection means detects that the substrate S has been attracted to the electrostatic chuck C. Then, in a second step, the voltage applied to the electrode of the first portion 242 is gradually increased, and the voltage increase is stopped when the detection means detects that the substrate S has been attracted to the electrostatic chuck C. Furthermore, in this example, the maximum voltage applied to the electrode of the second portion 244 in the first step and the maximum voltage applied to the electrode of the first portion 242 in the second step are controlled to be equal. Even in this case, the above-described advantageous effects can be obtained.

[0062] 11(b) shows an example of voltage control as follows. That is, in a first step, the voltage applied to the electrode of the second portion 244 is gradually increased, and the voltage increase is stopped when the detection means detects that the substrate S has been attracted to the electrostatic chuck C. Then, in a second step, the voltage applied to the electrode of the first portion 242 is gradually increased, and the voltage increase is stopped when the detection means detects that the substrate S has been attracted to the electrostatic chuck C. Furthermore, in this example, the maximum voltage applied to the electrode of the second portion 244 in the first step is controlled to be smaller than the maximum voltage applied to the electrode of the first portion 242 in the second step. Even in this case, the above-described effects can be obtained.

[0063] 12(a) shows an example of voltage control as follows. That is, after a voltage capable of attracting the substrate S is applied to the electrode of the second portion 244 (first step), a control is performed to apply a voltage capable of attracting the substrate S to the electrode of the first portion 242 (second step). Furthermore, after the detection means detects that the substrate S has been attracted to the electrostatic chucks C in both the first portion 242 and the second portion 244, control is performed to reduce the voltages applied to the electrodes of the first portion 242 and the second portion 244 within a range in which the substrate S can be attracted to the electrostatic chuck C. Furthermore, in this example, the maximum voltage applied to the electrode of the second portion 244 in the first step and In the second step, the maximum voltages applied to the electrodes of the first portion 242 are controlled to be equal to each other. Even in this case, the above-described effects can be obtained.

[0064] 12(b) shows an example of voltage control as follows. That is, after a voltage capable of attracting the substrate S is applied to the electrode of the second portion 244 (first step), a voltage capable of attracting the substrate S is applied to the electrode of the first portion 242 (second step). Furthermore, after the detection means detects that the substrate S has been attracted to the electrostatic chucks C in both the first portion 242 and the second portion 244, control is performed to reduce the voltages applied to the electrodes of the first portion 242 and the second portion 244 within a range in which the substrate S can be attracted to the electrostatic chuck C. Furthermore, in this example, the maximum voltage applied to the electrode of the second portion 244 in the first step is controlled to be smaller than the maximum voltage applied to the electrode of the first portion 242 in the second step. Even in this case, the above-described advantageous effects can be obtained.

[0065] 7, 10(b), 11(b), and 12(b), the maximum voltage applied to the electrodes of the second portion 244 is lower than the maximum voltage applied to the electrodes of the first portion 242. This has the effect of reducing the risk of electrostatic breakdown of devices such as TFT circuits formed on the substrate S. This point will be explained below. In this embodiment, as described with reference to FIG. 6, in the first portion 242 of the electrostatic chuck C, the widths (L) of the electrodes 250a and 250b are each 1 mm, and the width (S) of the space between the electrodes 250a and 250b is 1.5 mm. In contrast, in the second portion 244, the widths (L) of the electrodes 250c and 250d are each 9 mm, and the width (S) of the space between the electrodes 250c and 250d is 1.5 mm. As a result, the voltage applied to the second portion 244 (central region) to attract the substrate S to the electrostatic chuck C can be ±1.2 kV. In contrast, if the width (L) of the electrodes of the entire electrostatic chuck is 1 mm and the width (S) of the space between the electrodes is 1.5 mm, the voltage applied to the central region of the electrostatic chuck C must be ±2.0 kV in order to attract the substrate S to the electrostatic chuck C. It is known that electrostatic breakdown of devices occurs when a voltage of 2 kV or more is applied. In the examples shown in FIGS. 7, 10(b), 11(b), and 12(b), the maximum voltage applied to the electrodes of the second portion 244 can be ±1.2 kV, thereby preventing electrostatic breakdown of devices.

[0066] 7 and 11, the voltages applied to the electrodes of the first portion 242 and the second portion 244 are gradually increased, and the voltage increase is stopped when the detecting means detects that the substrate S has been attracted to the electrostatic chuck C. As a result, the substrate S is gradually attracted to the electrostatic chuck C, so that the deformation speed of the substrate S can be slowed down and the load on the substrate S can be suppressed.

[0067] 7 and 12, after voltages are applied to the electrodes of the first portion 242 and the second portion 244, the detection means detects that the substrate S has been attracted to the electrostatic chuck C in both the first portion 242 and the second portion 244. Then, control is performed to reduce the voltages applied to the electrodes of the first portion 242 and the second portion 244 within a range that allows the substrate S to be attracted to the electrostatic chuck C. This prevents a voltage greater than necessary from being applied after the substrate S has been attracted to the electrostatic chuck C, thereby reducing the amount of power consumed.

[0068] <Electronic device manufacturing method> Next, an example of a method for manufacturing an electronic device using the film formation apparatus and film formation method according to this embodiment will be described. Below, 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 illustrated.

[0069] First, the organic EL display device to be manufactured will be described. FIG. 13(b) is an overall view of 700 and shows the cross-sectional structure of one pixel.

[0070] As shown in FIG. 13(a), a plurality of pixels 702, each including a plurality of light-emitting elements, are arranged in a matrix in a display region 701 of an organic EL display device 700. 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" here refers to the smallest unit that enables a desired color to be displayed 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. The pixel 702 is often configured by a combination of red, green, and blue light-emitting elements, but may also be a combination of yellow, cyan, and white light-emitting elements, and is not particularly limited as long as it emits at least one color.

[0071] 13(b) is a partial cross-sectional schematic diagram taken along line BB in FIG. 13(a). A pixel 702 is composed of a plurality of light-emitting elements, each of which has a first electrode (anode) 704, a hole transport layer 705, one of light-emitting layers 706R, 706G, and 706B, an electron transport layer 707, and a second electrode (cathode) 708 on a substrate 703. Of these, the hole transport layer 705, the light-emitting layers 706R, 706G, and 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.

[0072] 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.

[0073] 13(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 smoothly inject 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.

[0074] Next, an example of a method for manufacturing an organic EL display device will be specifically described.

[0075] First, a circuit (not shown) for driving the organic EL display device and a substrate (mother glass) 703 on which a first electrode 704 is formed are prepared.

[0076] 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 area where the first electrode 704 is formed, thereby forming an insulating layer 709. This opening corresponds to the light-emitting area where the light-emitting element actually emits light.

[0077] The substrate 703 on which the insulating layer 709 is 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 device, 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 evaporation. In practice, the hole transport layer 705 is formed on the surface Since the display area 701 is formed to be larger than the display area 701, a high-resolution mask is not required.

[0078] Next, the substrate 703 on which up to the hole transport layer 705 has been formed is carried into a second organic material film formation apparatus. The substrate and a mask are aligned, the substrate is placed on the mask, and a red-emitting light-emitting layer 706R is formed on the portion of the substrate 703 where the red-emitting element is to be disposed.

[0079] 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 area 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.

[0080] The substrate on which the electron transport layer 707 has been formed is moved in a metallic evaporation material deposition device, and a second electrode 708 is deposited.

[0081] Thereafter, the substrate is transferred to a plasma CVD apparatus, where a protective layer 710 is formed, 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. After that, the organic EL display device 700 is completed after cutting.

[0082] If the substrate 703 on which the insulating layer 709 is 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.

[0083] <Film thickness measuring device> In the above embodiment, the electrostatic chuck C used when forming a thin film on a substrate S using a film formation source (in this embodiment, the evaporation source 240) in the film formation chamber 110 of the film formation apparatus 1 has been described as an example. However, the present invention can also employ the electrostatic chuck C when measuring the film thickness of a thin film formed on the substrate S. That is, in the film formation apparatus 1, for example, in the pass chamber 150 or buffer chamber 160 shown in FIG. 1, the substrate S on which a thin film has already been formed is adsorbed and held by the electrostatic chuck C, and the film thickness of the thin film is measured. FIG. 14 shows a configuration in which the pass chamber 150 functions as a film thickness measurement device. Such a device is disclosed, for example, in Japanese Patent Application Laid-Open No. 2023-79032, and will only be briefly described here. The pass chamber 150, which functions as a film thickness measurement device, includes the electrostatic chuck C and a substrate support unit 210 that supports the substrate S, similar to the film formation chamber 110. A measurement device 155 is provided within the pass chamber 150 as a measurement means for measuring film thickness. More specifically, the substrate S is disposed with the thin film formed on the substrate S facing downward, and the measuring device 155 is disposed vertically below the substrate S. The measuring device 155 has a light projecting and receiving unit that includes a light projecting unit for projecting light emitted from a light source vertically upward and a light receiving unit for receiving reflected light and sending it to a spectrometer. The spectrometer has a light input port, disperses the input light, measures the light intensity for each wavelength band, and transmits information about the measured light intensity to the control unit 270. The control unit 270 calculates the measured film thickness based on the light intensity measured by the spectrometer. Known techniques can be used to calculate the measured film thickness. For example, the relationship between the film thickness of the thin film formed on the substrate S and the reflectance of the substrate S at a certain wavelength (nm) can be measured in advance, and the film thickness can be calculated from this relationship and the measured reflectance.

[0084] In this way, the configuration of the electrostatic chuck C described in the above embodiment can also be adopted for the electrostatic chuck C used in the device for measuring the thickness of a thin film formed on a substrate S. The same applies to the procedure for chucking the substrate S by the electric chuck C. For example, in the example of FIG. 7 described in the above embodiment, the procedure up to time 4 is the same as in the above embodiment, and from time 4 to time N, film thickness measurement is performed in the pass chamber 150. [Explanation of symbols]

[0085] 1: Film formation apparatus 10: Substrate 12: First area 14: Second area 110: Film formation chamber 120: Mask stock chamber 130: Transfer chamber 140: Transfer robot 150: Pass chamber 155: Measurement device 160: Buffer chamber 170: Rotation chamber 200: Vacuum chamber 210: Substrate support part 220: Mask 221: Mask table 222: Frame 224: Crosspiece 226: Metal mask foil 240: Evaporation source 242: First part 244: Second part 252: Electrostatic chuck actuator 261: Camera 270: Control unit 275: Detection unit 280: Alignment stage 281: Chamber fixing part 282: Actuator part 283: Connection part 290: Power supply C: Electrostatic chuck M: Mask S: Substrate

Claims

1. A film forming apparatus including an electrostatic chuck that attracts and holds a substrate by electrostatic force, the electrostatic chuck includes a first portion that attracts a peripheral region of the substrate and a second portion that attracts a central region of the substrate; the number of electrodes per unit length of the first portion is greater than the number of electrodes per unit length of the second portion; a ratio of the width of the electrodes to the inter-electrode space in the second portion is greater than a ratio of the width of the electrodes to the inter-electrode space in the first portion; a voltage being applied to the electrode of the second portion to attract the substrate, and then a voltage being applied to the electrode of the first portion to attract the substrate;

2. 2. The film deposition apparatus according to claim 1, wherein a maximum voltage applied to the electrode of the second portion is lower than a maximum voltage applied to the electrode of the first portion.

3. a detection means for detecting whether the substrate is attracted to the electrostatic chuck; 3. The film forming apparatus according to claim 1, wherein the voltages applied to the electrodes of the first and second portions are gradually increased, and the voltage increase is stopped when the detection means detects that the substrate has been attracted to the electrostatic chuck.

4. a detection means for detecting whether the substrate is attracted to the electrostatic chuck; 3. The film forming apparatus according to claim 1, wherein after applying a voltage to the electrodes of the first and second portions, the detection means detects that the substrate has been attracted to the electrostatic chuck in both the first and second portions, and then the voltage applied to the electrodes of the first and second portions is reduced within a range that allows the substrate to be attracted to the electrostatic chuck.

5. 3. The film forming apparatus according to claim 1, further comprising a film forming source for forming a thin film on the substrate through a mask in a state where the mask is positioned on the film forming surface of the substrate.

6. The film forming apparatus according to claim 5 , wherein the thin film is formed in the central region of the substrate that is attracted to the second portion.

7. 6. The film deposition apparatus according to claim 5, wherein the film deposition source is disposed vertically below the substrate.

8. 3. The film forming apparatus according to claim 1, further comprising a measuring means for measuring the thickness of the thin film formed on the substrate attracted to the electrostatic chuck.

9. 9. The film deposition apparatus according to claim 8, wherein the substrate is placed with the thin film facing downward, and the measuring means is disposed vertically below the substrate.

10. 1. A film formation method for forming a thin film on a substrate using a film formation apparatus equipped with an electrostatic chuck that attracts and holds a substrate by electrostatic force, comprising: the electrostatic chuck includes a first portion that attracts a peripheral region of the substrate and a second portion that attracts a central region of the substrate; the number of electrodes per unit length of the first portion is greater than the number of electrodes per unit length of the second portion; The ratio of the width of the electrodes to the inter-electrode space in the second portion is The ratio of the electrode width to the inter-electrode space is greater than the ratio of the electrode width to the inter-electrode space; a first step of applying a voltage to the electrode of the second portion to attract the substrate; a second step of applying a voltage to an electrode of the first portion to attract the substrate after the substrate is attracted to the second portion in the first step; A film forming method comprising the steps of:

11. 11. The film forming method according to claim 10, wherein the maximum voltage applied to the electrode of the second portion in the first step is lower than the maximum voltage applied to the electrode of the first portion in the second step.

12. the film forming apparatus is provided with a detection means for detecting whether the substrate is attracted to the electrostatic chuck, In the first step, the voltage applied to the electrode of the second portion is gradually increased, and the voltage increase is stopped when the detection means detects that the substrate has been attracted to the electrostatic chuck; 12. The film forming method according to claim 10, wherein in the second step, the voltage applied to the electrode of the first portion is gradually increased, and the increase in voltage is stopped when the detection means detects that the substrate has been attracted to the electrostatic chuck.

13. A method for manufacturing an electronic device, comprising the step of manufacturing an electronic device by using the film forming method according to claim 10 or 11.

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