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

Abstract

Provided are a film forming apparatus capable of enhancing positioning accuracy of a mask, a film forming method, and a method for manufacturing an electronic device.　A film forming apparatus 1 forms a thin film on a substrate held by an electrostatic chuck through a mask 16 held by a mask frame 15 placed on a mask base 33 by using a film forming material discharged from an evaporation source 5 in a chamber. The apparatus is characterized in that the mask base 33 and the mask frame 15 are positioned by fitting a kinematic coupling, and the mask 16 is provided with a projecting part that is pressed when the mask frame 15 is positioned on the mask base 33.

Description

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

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

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

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

[0004] The film material is released from an evaporation source installed on the bottom of the vacuum chamber and deposited on the substrate through a mask. Repeated film deposition causes the film material to accumulate on the mask. Therefore, the mask must be replaced every time a certain number of films are deposited on the substrate. At this time, the mask with the deposited film material must be removed from the vacuum chamber and a new mask must be installed in the specified position with high precision.

[0005] Kinematic coupling technology is known as a method for positioning a mask with high precision (see Patent Document 1). Several kinematic coupling techniques are known, but for example, a kinematic coupling in which three V-grooves and a spherical seat fit together is provided, and high-precision positioning can be achieved by constraining six degrees of freedom.

[0006] Japanese Patent Application Publication No. 5-267116

[0007] Kinematic couplings enable highly accurate positioning by properly fitting multiple points. However, if some points do not fit properly due to some influence, high accuracy positioning is not possible.

[0008] An object of the present invention is to provide a film formation apparatus, a film formation method, and a method for manufacturing an electronic device that can improve the positioning accuracy of a mask.

[0009] The film formation apparatus of the present invention is a film formation apparatus that forms a thin film on a substrate held by a substrate holding member using a film formation material released from a film formation source within a chamber, via a mask held by a mask holding member placed on a mask table, and is characterized in that the mask table and the mask holding member are positioned by fitting kinematic mounts at multiple locations, and any one of the mask, the mask holding member, the substrate, and the substrate holding member is provided with a convex portion that is pressed when the mask holding member is positioned on the mask table.

[0010] As described above, according to the present invention, the accuracy of mask positioning can be improved.

[0011] Schematic diagram of a film forming apparatus according to Example 1 Enlarged view of a magnetic levitation stage according to Example 1 Top view of a magnetic levitation stage according to Example 1 Diagram showing a mask and a mask frame according to Example 1 Diagram showing a mask table according to Example 1 Diagram explaining engagement of a kinematic coupling according to Example 1 Diagram explaining the positional relationship between a kinematic coupling and a convex portion according to Example 1 Diagram explaining the positional relationship between a kinematic coupling and a convex portion according to Example 1 Operation flow diagram according to Example 1 Diagram showing force received by a magnetic levitation stage according to Example 1 when a mask is attracted Control block diagram of a magnetic levitation stage according to Example 1 Diagram showing the configuration of a controller for each axis according to Example 1 Diagram showing the concept of force action during tracking control according to Example 1 Diagram explaining a mask according to Example 2 Diagram explaining a mask according to Example 2 Diagram explaining an organic EL display device

[0012] The following detailed description of the present invention will be given by way of example with reference to the accompanying drawings, although the dimensions, materials, shapes, relative positions, etc. of the components described in the examples are not intended to limit the scope of the present invention unless otherwise specified.

[0013] 1 to 4, a film formation apparatus, a film formation method, and a method for manufacturing an electronic device according to a first embodiment of the present invention will be described. X, Y, and Z axes are shown in Fig. 1 to 3. The Z axis is an axis parallel to the vertical direction, and the X and Y axes are axes parallel to the horizontal direction and perpendicular to each other.

[0014] <Film Forming Apparatus> A film forming apparatus 1 according to this embodiment will be described with reference to FIG. 1 . FIG. 1 is a schematic diagram of the film forming apparatus 1 according to this embodiment, showing the configuration of the film forming apparatus 1 as viewed from the front. In FIG. 1 , the area enclosed by the dotted line includes a magnetic levitation stage 2. The magnetic levitation stage 2 is fixed to the upper corners or upper side surfaces of a vacuum chamber by stage supports 6. The vacuum chamber generally has a hexahedral configuration, consisting of vacuum chamber side surfaces 3, a vacuum chamber bottom surface 32, and a vacuum chamber top plate 11. A thin film is formed on a substrate via a mask 16 using film forming material released from an evaporation source 5 (a film forming source) installed on the vacuum chamber bottom surface 32. The mask 16 is magnetic and configured to be attracted by an attraction magnet 18 (a magnet that can move up and down relative to the magnetic levitation stage 2). The attraction magnet 18 is configured to be raised and lowered by an elevation mechanism 18X. The lifting mechanism 18X can employ various known technologies, such as a ball screw mechanism or a rack-and-pinion mechanism. The magnetic levitation stage 2 is configured so that its position can be controlled based on the measurement results of a laser displacement meter 17 installed on the mask table 33. The film forming apparatus 1 also includes a control unit 35. The control unit 35 controls various mechanisms, the evaporation source 5, and film formation. The control unit 35 can be configured, for example, by a computer having a processor, memory, storage, I / O, and the like. In this case, the functions of the control unit 35 are realized by the processor executing a program stored in the memory or storage. The computer may be a general-purpose personal computer, an embedded computer, or a PLC (programmable logic controller). Alternatively, some or all of the functions of the control unit 35 may be configured using circuits such as an ASIC or FPGA. A control unit 35 may be provided for each film forming apparatus 1, or one control unit 35 may control multiple film forming apparatuses 1.

[0015] Next, the configuration of the vibration isolation table support section on the atmosphere side will be described. Vibration isolation tables 9a and 9b are disposed on a vacuum chamber top plate 11 via vibration isolation table bases 10a and 10b. Supporting the support frame 8 on the vibration isolation tables 9a and 9b suppresses vibrations transmitted from the vacuum chamber. Furthermore, a mask table 33 is supported within the vacuum chamber by mask support columns 13a and 13b that are moved up and down by mask guide mechanisms 12a and 12b provided on the support frame 8. A mask frame 15, which serves as a mask holding member, is carried into the apparatus by a robot hand (not shown) and placed on the mask table 33.

[0016] When the robot hand enters or leaves the apparatus to carry the mask frame 15 or substrate into the apparatus, the mask guide mechanisms 12a and 12b lower the mask stage 33 to a position where it does not interfere with the movement of the robot hand. When the mask guide mechanisms 12a and 12b move up and down, the bellows 14a and 14b expand and contract. These bellows 14a and 14b maintain the vacuum state inside the chamber.

[0017] If the positioning accuracy of the robot hand or the positional deviation when placing the mask, etc. is large, a rotational / translation mechanism may be required in addition to the up / down drive to bring the mask, etc. into the camera's field of view. This is a well-known technique, so its explanation will be omitted.

[0018] The alignment cameras 7a and 7b are also supported by a support frame 8. This suppresses vibrations transmitted from the vacuum chamber to the alignment cameras 7a and 7b, enabling highly accurate measurements. A viewport for alignment measurement is installed on the chamber top plate 11, allowing alignment measurement from the atmospheric side. The alignment cameras 7a and 7b capture images of alignment marks 102a, 102b, 102c, and 102d (see FIG. 4) using transmitted light from illuminators 24a and 24b installed on the underside of the mask table 33. Four alignment cameras and four illuminators are installed, including those not shown, and are configured to detect the positions of alignment marks formed on the substrate.

[0019] <Magnetic levitation stage> The magnetic levitation stage 2 will be described using Figures 2 and 3. Figure 2 is an enlarged view of the magnetic levitation stage 2 in Figure 1, and Figure 3 is a top view of the magnetic levitation stage 2. Note that Figure 3 also illustrates the stator provided on the stage support 6 and the attracting magnet 18 in order to clarify the positional relationship between the mover, stator, etc.

[0020] The magnetic levitation stage 2 includes a stage frame 31, and weight compensation magnet movers 22a, 22b, 22c, and 22d and linear motor movers 20a, 20b, 20c, and 20d fixed to the stage frame 31. The weight compensation magnet movers 22a, 22b, 22c, and 22d support the magnetic levitation stage 2 in a non-contact state with respect to the stage support 6 in order to cancel the weight of the magnetic levitation stage 2. The linear motor movers 20a, 20b, 20c, and 20d generate thrust to move the magnetic levitation stage 2 in a non-contact state with respect to the stage support 6. An electrostatic chuck 25 serving as a substrate holding member is fixed to the underside of the magnetic levitation stage 2. The electrostatic chuck 25 can attract a substrate 27, which is the target of film formation, in a face-down state.

[0021] Gravity compensation magnet stators 23a, 23b, 23c, and 23d are fixed to the underside of the stage support 6 so as to face the gravity compensation magnet movers 22a, 22b, 22c, and 22d, respectively. A magnetic force equivalent to the gravity of the magnetic levitation stage 2 is generated between the gravity compensation magnet movers and stators, and the magnetic levitation stage 2 is supported by the stage support 6 in a non-contact state.

[0022] Additionally, linear motor stators 21a, 21b, 21c, and 21d are fixed to the underside of the stage support 6 so as to face the linear motor movers 20a, 20b, 20c, and 20d, respectively. Thrust that moves the magnetic levitation stage 2 is generated by changes in the value of current flowing through the coils built into these linear motor stators 21a, 21b, 21c, and 21d. In the vertical direction, the weight of the magnetic levitation stage 2 is canceled by the weight compensation magnets, so the thrust generated by the linear motor is minimal. Therefore, only a small amount of current is required, and the amount of heat generated by current flow is minimal, eliminating the problem of deformation or damage to each component due to heat. However, if necessary, the coils may be covered with a water-cooled jacket and actively cooled by flowing a refrigerant through it.

[0023] Linear motor movers 20a, 20b, 20c, and 20d are arranged at four corner locations on the top surface of stage frame 31. This allows for translational drive of magnetic levitation stage 2 in the X and Y directions and rotational drive around the Z axis. Furthermore, by arranging at least three or more linear motors (not shown) that generate thrust in the Z axis direction, it is possible to move magnetic levitation stage 2 with six degrees of freedom. In this embodiment, linear motors arranged at a total of seven locations are used to move magnetic levitation stage 2 with six degrees of freedom. Furthermore, gravity compensation magnet movers 22a, 22b, 22c, and 22d are arranged at four symmetrical locations around the center of gravity of magnetic levitation stage 2. This allows for the application of moment force, enabling stable levitation of magnetic levitation stage 2.

[0024] <Alignment Mechanism> The alignment mechanism (positioning mechanism) for the substrate 27 and the mask 16 will now be described. The relative position of the magnetic levitation stage 2 with respect to the mask table 33 is measured by laser displacement meters 17. These laser displacement meters 17 are arranged in a total of six locations: two in the X direction, one in the Y direction, and three in the Z direction. Geometric coordinate transformation is performed based on the information from the six laser displacement meters 17, and the information is converted into a position with six degrees of freedom around the center of gravity of the magnetic levitation stage 2. Control calculations are performed based on the six degrees of freedom position information, and six degrees of freedom thrust commands are determined. Based on the six degrees of freedom thrust commands, currents are passed through the coils of each linear motor arranged in seven locations, causing the magnetic levitation stage 2 to move, thereby enabling the magnetic levitation stage 2 to be positioned with high precision with respect to the mask table 33.

[0025] The laser displacement meter 17 is fixed near the mask 16 on the mask table 33. This allows direct positioning of the mask 16 and the substrate 27 in a vacuum environment without being affected by Abbe error or the like. Furthermore, vibrations from the vacuum chamber are suppressed by the vibration isolation tables 9a and 9b on which the support frame 8 is mounted via the mask table 33, enabling stable measurements. The magnetic levitation stage 2 is supported by a gravity compensation magnet that is non-contact and has low magnetic spring properties, and vibrations from the vacuum chamber are similarly suppressed. With the above configuration, the relative positions of the magnetic levitation stage 2 and the mask table 33 can be determined with high precision, thereby enabling highly accurate alignment of the substrate 27 and the mask 16.

[0026] <Mask and Substrate> The mask 16 and the substrate 27 will be described in more detail. The mask 16 is provided with a plurality of through-holes corresponding to the pixel pattern at equal intervals, and is configured so that the film-forming material passing through the through-holes is formed on the surface of the substrate 27. The mask 16 is made of a material such as a thin membrane made of a thermally expandable metal foil such as invar or a silicon wafer. The mask 16 is fixed to a mask frame 15, which serves as a mask holding member, and is transported together with the frame by a robot hand and placed on a mask table 33. The mask 16 and the mask frame 15 can be fixed by various known techniques, such as spot welding in a stretched state, mechanical clamping, or adhesive bonding. It is desirable to prevent distortion of the mask 16 during fixation.

[0027] The substrate 27 is held by an electrostatic chuck 25 serving as a substrate holding member. An attraction magnet 18 is configured to be able to approach, but not contact, the surface of the electrostatic chuck 25 opposite the attracting surface, and is configured to be able to generate a magnetic flux necessary to attract the mask 16. The electrostatic chuck 25 and the substrate 27 are non-magnetic, and the magnetic flux of the attraction magnet 18 can generate an attraction force that attracts the mask 16 vertically upward. This attraction force allows the mask 16 to be tightly attached to the substrate 27. Ensuring close contact here makes it possible to prevent the film-forming material from wrapping around (shadowing) during film formation.

[0028] <Positioning the Mask on the Mask Table> The positioning of the mask 16 on the mask table 33 will be described with reference to Figures 4 to 8. Figure 4 shows the mask 16 and mask frame 15 according to this embodiment, with Figure 4(a) being a side view of the mask 16 and mask frame 15, Figure 4(b) being a top view of the mask 16 and mask frame 15, and Figure 4(c) being a bottom view of the mask 16 and mask frame 15.

[0029] The underside of the mask frame 15 is provided with spherical seats 100 (100a, 100b, 100c) at multiple locations (specifically, three locations) as hemispherical portions constituting the kinematic coupling. These spherical seats 100a, 100b, 100c are preferably installed at equal intervals of 120° from the center of gravity of the mask 16 (which in this embodiment coincides with the center of the mask 16 and the center of the mask frame (centroid in the plan view)). The upper surface of the mask 16 is provided with protrusions 101 (101a, 101b, 101c). Furthermore, the mask 16 is provided with alignment marks 102a, 102b, 102c, 102d, which are photographed by the alignment camera during alignment, as described above.

[0030] 5A and 5B are diagrams showing the mask table 33 according to this embodiment, with FIG. 5A being a side view of the mask table 33 and FIG. 5B being a top view of the mask table 33. Grooves constituting kinematic coupling are provided at multiple locations (specifically, three locations) on the top surface of the mask table 33. These grooves are composed of V-shaped grooves 110 (110a, 110b, 110c) having a pair of side surfaces whose distance narrows toward the bottom of the groove.

[0031] As described above, in this embodiment, the spherical seat 100 constituting the kinematic coupling is provided on the lower surface of the mask frame 15, and a groove (V-shaped groove 110) is provided on the upper surface of the mask table 33. When the mask 16 is placed on the mask table 33, the spherical seat 100 is fitted into the V-shaped groove 110, thereby forming a kinematic coupling that positions the mask frame 15 and the mask table 33 relative to each other with six degrees of freedom, thereby achieving accurate positioning. Note that this embodiment shows a configuration in which the spherical seat 100 is provided on the mask frame 15 and the groove is provided on the mask table 33, but it is also possible to adopt a configuration in which the mask table 33 is provided with a spherical seat constituting the kinematic coupling and the mask frame 15 is provided with a groove constituting the kinematic coupling. Furthermore, this embodiment shows a configuration in which a spherical seat and a V-shaped groove are used as the kinematic coupling, but the kinematic coupling is not limited to these configurations, and other known techniques can also be adopted.

[0032] In this embodiment, illumination devices 24a, 24b, 24c, and 24d are embedded in the mask table 33. In this embodiment, the illumination devices 24a, 24b, 24c, and 24d illuminate the alignment marks 102a, 102b, 102c, and 102d, and the transmitted light is photographed, thereby performing alignment. The alignment method using alignment marks is a well-known technique, and therefore a description thereof will be omitted.

[0033] As described above, repeated film formation on the substrate 27 causes deposition material to accumulate on the mask 16, and therefore the mask 16 needs to be replaced every time a predetermined number of films are formed on the substrate 27. As described with reference to Figure 1, the mask guide mechanisms 12a and 12b lower the mask table 33 together with the mask support struts 13a and 13b, thereby widening the gap between the electrostatic chuck 25 holding the substrate 27 and the mask table 33. In this state, a robot hand (not shown) enters the apparatus, removes the mask frame 15 from the mask table 33, and places a new mask frame 15 on the mask table 33.

[0034] FIG. 6 shows an example of a state in which the kinematic coupling is engaged (a state in which the spherical seat 100 is engaged with the V-groove portion 110). When the V-groove portion 110 of the kinematic coupling and the spherical seat 100 are in contact with each other at two points, 120a and 120b (see FIG. 6(a)), six degrees of freedom of positioning are achieved, enabling the mask frame 15 and mask 16 to be positioned accurately relative to the mask table 33. However, when the mask frame 15 is placed by the robot hand, depending on the positioning accuracy of the transfer robot, the V-groove portion 110 and the spherical seat 100 may be in contact with each other at a single point, 120c, as shown in FIG. 6(b). It is desirable to apply a coating to the surfaces of the V-groove portion 110 and the spherical seat 100 to reduce the coefficient of friction, so that the mask frame 15 can slide under its own weight from the single-point contact state shown in FIG. 6(b) to the two-point contact state shown in FIG. 6(a).

[0035] However, even if a coating is applied, wear of the coating may result in the single-point contact state shown in FIG. 6( b). Therefore, in this embodiment, a method is adopted in which the kinematic coupling is properly engaged (the spherical seat 100 and the V-groove 110 are properly engaged) even if the mask frame 15 does not slip due to its own weight and does not reach the state shown in FIG. 6( a). That is, in this embodiment, a convex portion 101 provided on the upper surface of the mask 16 is pressed when the mask frame 15 is positioned on the mask table 33, so that the mask frame 15 reaches the state shown in FIG. 6( a) even if it does not slip due to its own weight. This point will be described in more detail below.

[0036] FIG. 7 is a diagram illustrating the positional relationship between the kinematic coupling and the convex portions. FIG. 7A is a plan view of the mask, etc., and FIG. 7B is a side view of the mask, etc. While FIG. 4 illustrates a case where the mask frame 15 and the mask 16 have substantially the same external dimensions, FIG. 7 illustrates a case where the external dimensions of the mask frame 15 are larger than those of the mask 16. The convex portions 101 (101a, 101b, 101c) on the upper surface of the mask 16 are positioned closer to the center of gravity G of the mask 16 than the kinematic coupling (the spherical seat 100 and the V-groove portion 110). More specifically, when viewed perpendicularly to the surface of the mask 16, the convex portions 101 are positioned within a triangular region (see the grid-shaped hatched area in FIG. 7A) connecting the center of gravity G and both ends of the pair of side surfaces of the V-groove portion 110 in the groove width direction.

[0037] If the convex portion 101S is arranged on the opposite side of the center of gravity G of the mask with respect to the kinematic coupling (see FIG. 8(a)), when a pressing force FS acts on the convex portion 101S toward the mask table 33, a moment MS acts in a direction in which the spherical seat 100 moves away from the V-groove portion 110. This may cause the fit between the spherical seat 100 and the V-groove portion 110 to become unstable. Therefore, it is desirable to arrange the convex portion 101 closer to the center of gravity G of the mask than the kinematic coupling.

[0038] Furthermore, even if the convex portion 101T is disposed closer to the center of gravity G of the mask than the kinematic coupling, if the convex portion 101T is disposed outside the lattice-shaped hatched area shown in FIG. 7A in the width direction R (see FIG. 8B), when a pressing force FT acts on the convex portion 101T toward the mask table 33, a moment MT acts in a direction that moves the spherical seat 100 away from the V-groove portion 110. This may cause the engagement between the spherical seat 100 and the V-groove portion 110 to become unstable. Therefore, it is desirable to dispose the convex portion 101 within the above-mentioned range in the width direction R. As a result, as shown in FIG. 8B, when a pressing force F acts on the convex portion 101 toward the mask table 33, the spherical seat 100 can be moved toward the bottom of the V-groove portion 110.

[0039] As described above, it is desirable to arrange the convex portion 101 within the hatched grid portion in Fig. 7(a). Furthermore, in this embodiment, as shown in Fig. 7(a), a configuration is adopted in which the center of gravity G of the mask 16 and the convex portion 101 are aligned on a straight line where a pair of side surfaces of the V-groove portion 110 intersect. This makes it possible to more reliably move the spherical seat 100 toward the bottom of the V-groove portion 110 when a pressing force acts on the convex portion 101 toward the mask table 33. In other words, it is possible to more reliably transition from the state shown in Fig. 6(b) to the state shown in Fig. 6(a).

[0040] In this embodiment, the convex portions 101 are provided on the mask 16. However, convex portions having the same function may be provided on a member other than the mask 16. For example, the convex portions 101 may be provided on the mask frame 15, as shown in FIG. 7A, as shown by convex portions 101ax, 101bx, and 101cx. The convex portions 101 may also be provided on the substrate 27, as shown in FIG. 7B, as shown by convex portions 101by. Furthermore, the convex portions 101 may also be provided on the electrostatic chuck 25, as shown in FIG. 7C, as shown by convex portions 101az and 101cz. Of course, even when the convex portions 101 are provided on any of the mask frame 15, the substrate 27, and the electrostatic chuck 25, it is preferable that the convex portions 101 be arranged within the hatched grid in FIG. 7A.

[0041] As described above, in the film formation apparatus 1 according to this embodiment, the convex portion 101 is pressed when the mask frame 15 is positioned on the mask table 33. That is, the control unit 35 performs control to press the convex portion 101 when the mask frame 15 is positioned on the mask table 33. More specifically, the control unit 35 performs tracking control to engage the kinematic coupling by pressing the convex portion 101 when the mask frame 15 is positioned on the mask table 33 in accordance with the movement of the magnetic levitation stage 2. Furthermore, during this tracking control, the control unit 35 determines the engagement state of the kinematic coupling based on the position of the magnetic levitation stage 2, thereby ensuring a more reliable engagement between the spherical seat 100 and the V-groove portion 110.

[0042] <Operation Flow> With reference to Fig. 9, an operation flow from carrying the substrate 27 into the vacuum chamber and holding it on the electrostatic chuck 25 to performing film formation (evaporation) will be described. In the following description, the rotation axis around the X axis is referred to as the ωx axis, the rotation axis around the Y axis is referred to as the ωy axis, and the rotation axis around the Z axis is referred to as the ωz axis. In addition, in the flow shown in Fig. 9, an example of a case where impedance control is adopted will be described as an example of scanning control.

[0043] <<Step S1>> The mask table 33, which has been lowered for the purpose of replacing the mask 16, is raised to a predetermined position.

[0044] <<Step S2>> The control mode of the magnetic levitation stage 2 is switched, for example, to torque control for the Z axis and impedance control for the ωx and ωy axes, and the substrate 27 is made to conform to the protrusions 101 a, 101 b, and 101 c provided on the upper surface of the mask 16 and pressed against them with a predetermined force (pressing step). This allows the substrate 27 to conform to all three of the protrusions on the upper surface of the mask 16.

[0045] <<Step S3>> When the substrate 27 is caused to conform to the protrusions 101a, 101b, and 101c, it is determined whether the coordinates of the Z axis, ωx axis, and ωy axis of the magnetic levitation stage 2 are all within a predetermined range or outside the range. If all are within the range, it is determined that all three points of the kinematic coupling are in a two-point contact state (the state shown in FIG. 6A), and the process proceeds to step S5. If one or more are outside the range, it is determined that at least one or more points of the kinematic coupling are in a one-point contact state (for example, the state shown in FIG. 6B), and the process proceeds to step S4. In this way, in step S3, the engagement state of the kinematic coupling is determined based on the position of the magnetic levitation stage 2 during conformance control.

[0046] <<Step S4>> The ωx-axis and ωy-axis are switched to position control mode, and with the magnetic levitation stage 2 returned to horizontal, the pressing force of the Z-axis torque control is increased by a predetermined amount to press in the mask. After that, the pressing force of the Z-axis torque control is returned to the initial setting value, and the process returns to step S2, where the same operation is performed again. The same operation is repeated until it is determined in step S3 that the coordinates of the Z-axis, ωx-axis, and ωy-axis of the magnetic levitation stage 2 are all within the predetermined range. This allows a two-point contact state to be achieved at all three locations of the kinematic coupling.

[0047] <<Step S5>> The Z-axis, ωx-axis, and ωy-axis coordinates of the magnetic levitation stage 2 when the substrate 27 is aligned with the convex portions 101a, 101b, and 101c are stored. The Z-axis, ωx-axis, and ωy-axis are switched to position control mode, the stored ωx-axis and ωy-axis coordinates are maintained, and the Z-axis is moved to a position elevated a predetermined amount from the stored coordinates. This allows for highly accurate parallelism and gap between the substrate 27 and the mask 16 to be achieved regardless of machine differences between the substrate 27 and the mask 16, and alignment is performed in a non-contact state. This alignment adjusts the positions of the mask 16 and the substrate 27 in directions parallel to the horizontal direction (X direction and Y direction) without rotating the substrate 27 around the ωx-axis and ωy-axis.

[0048] <<Step S6>> The control mode of the magnetic levitation stage 2 is switched, for example, to torque control for the Z axis and impedance control for the ωx and ωy axes, and alignment is performed by making the substrate 27 conform to the convex portions 101a, 101b, and 101c on the upper surface of the mask 16 and pressing them with a predetermined force. This allows alignment to be performed with a narrower gap between the substrate 27 and the mask 16 than in step S5, enabling more accurate alignment. When the substrate 27 conforms to the convex portions 101a, 101b, and 101c, the substrate 27 and the mask 16 are parallel. Therefore, alignment may be performed after changing the ωx and ωy axes to position control mode while pressing the Z axis with a predetermined force using torque control.

[0049] <<Step S7>> As described above, in this embodiment, alignment is performed between the substrate 27 and the mask 16 in a non-contact state (step S5), and then more precise alignment is performed with the substrate 27 and the mask 16 in slight contact (step S6). Then, in step S7, the attraction magnet 18 is lowered, and film formation (evaporation) is performed with the substrate 27 and the mask 16 in complete contact (film formation step).

[0050] In this embodiment, the attraction magnet 18 is lowered while changing the torque of the Z axis of the magnetic levitation stage 2 according to the position of the attraction magnet 18, and the mask 16 is attracted to the substrate 27, and then deposition is performed. The reason for changing the torque of the Z axis in this manner will be explained. When the attraction magnet 18 descends and attracts the mask 16, the magnetic levitation stage 2 is pushed back by the force from the mask 16. FIG. 10(a) shows an example of the relationship between the position of the attraction magnet 18 and the force that the magnetic levitation stage 2 receives from the mask 16. FIG. 10(b) is an explanatory diagram of the force that the magnetic levitation stage 2 receives from the mask 16, and is a diagram that schematically shows the magnetic levitation stage 2, etc. As can be seen from these figures, the attraction magnet 18 attracts the mask 16 upward, and therefore the force F that the magnetic levitation stage 2 receives from the mask 16 varies depending on the position of the attraction magnet 18. Ｍ Then, the force F that the magnetic levitation stage 2 presses against the mask frame 15 becomes weaker than the Z-axis torque Fz of the stage, as shown in the following equation (1): F=Fz-F Ｍ (1) Force F acting on the magnetic levitation stage 2 from the mask 16 Ｍbecomes larger than the Z-axis torque Fz of the stage, the magnetic levitation stage 2 may separate from the mask frame 15, so it is desirable to change the Z-axis torque of the magnetic levitation stage 2. Therefore, it is desirable to store in advance in a memory or the like a relationship equation between the position of the attractive magnet 18 and the force that the magnetic levitation stage 2 receives from the mask 16 (corresponding to the contact force between the substrate 27 and the mask 16), or a table thereof, and have the control unit 35 change the Z-axis torque of the magnetic levitation stage 2 depending on the position of the attractive magnet 18. In other words, it is desirable to store in advance the relationship between the position of the attractive magnet 18 and the contact force between the substrate 27 and the mask 16, and have the control unit 35 change the Z-axis torque Fz based on this relationship so that the force F that causes the magnetic levitation stage 2 to contact the substrate 27 and the mask frame 15 remains constant. Furthermore, if the alignment between the substrate 27 and the mask 16 becomes misaligned while the attraction magnet 18 is descending, the alignment may be performed at a position midway while the attraction magnet 18 is descending, as long as it is before the mask 16 comes into close contact with the substrate 27.

[0051] As described above, the flow shown in FIG. 9 illustrates a case where impedance control is used for tracking control. However, tracking control methods other than impedance control can also be used. Below, other examples of tracking control are described with reference to FIGS. 11 to 13. Here, an example is described in which a thrust command based on the velocity of the magnetically levitated stage 2 is issued and feedback control is performed to add a predetermined force to the thrust command. FIG. 11 shows the control block for the magnetically levitated stage 2. The output of the six-degree-of-freedom controller is coordinate-converted into the thrust of each linear motor, which then applies the thrust to the magnetically levitated stage 2. The position detected by the laser displacement sensor is coordinate-converted into a six-degree-of-freedom position and fed back, thereby controlling the position of the magnetically levitated stage 2. FIG. 12 shows the configuration of the controller for each axis. The controller for each axis uses PID control, which is the sum of a value obtained by multiplying the position proportional gain Kp, a value obtained by multiplying the position integral value by the integral gain Ki, and a value obtained by multiplying the position derivative value by the derivative gain Kd. Only the Z axis can add the torque command shown in FIG. 12. When the substrate 27 is caused to conform to the convex portions 101a, 101b, and 101c of the mask 16, the proportional gain Kp and integral gain Ki for the Z-axis, ωx, and ωy-axis are set to zero. This sets up a position differentiation, i.e., velocity feedback control mode. Figure 13 illustrates the concept of force application during conformance control. When a torque command F is applied to descend the Z-axis, initially, the velocity is zero and only a downward force F is applied, as shown in Figure 13(a). The magnetic levitation stage 2 then begins to move downward. If the velocity command is set to zero, a force Fr acts in the opposite direction (upward) to the velocity, as shown in Figure 13(b). After this reverse force and the torque command balance, the magnetic levitation stage 2 descends at an inertial velocity v. When the substrate 27 and mask 16 come into contact, the velocity returns to zero, and only the torque command F can be applied to the mask 16, as shown in Figure 13(c). Since no torque command is given to the ωx and ωy axes, the ωx and ωy axes are tilted so that an equal force is applied to the convex portions 101a, 101b, and 101c of the mask 16, and a tracing operation is performed.

[0052] As described above, the film formation apparatus 1 and film formation method according to this embodiment can improve the positioning accuracy of the mask frame 15 and the mask 16 relative to the mask table 33. Accordingly, the accuracy of film formation on the substrate 27 can be improved.

[0053] 14 and 15 show a second embodiment of the present invention. In the first embodiment, a convex portion is provided on the mask. In contrast, in the second embodiment, a convex portion is provided on the mask frame, and an opening is provided on the mask so that the convex portion can be inserted therein. The other configurations and functions are the same as those of the first embodiment, and therefore, a description of the same components will be omitted as appropriate.

[0054] 14A and 14B are diagrams showing a mask and a mask frame according to Example 2, with Fig. 14A being a plan view and Fig. 14B being a side view, and Fig. 15 is a side view of the substrate, mask, and mask frame according to Example 2, showing the state in which the mask is attracted by a magnet.

[0055] In this embodiment as well, a mask 403 is fixed to a mask frame 401 serving as a mask holding member. In this embodiment, the outer peripheries of the mask frame 401 and the mask 403 are fixed by a joint 404. Also in this embodiment as well, spherical seats 402 (402a, 402b, 402c) serving as hemispherical portions constituting a kinematic coupling are provided at multiple locations (specifically, three locations) on the underside of the mask frame 401.

[0056] In this embodiment, convex portions 405 (405a, 405b, 405c) are provided on the upper surface of the mask frame 401. The mask 403 is provided with openings 406 (406a, 406b, 406c) that do not come into contact with the convex portions 405 but allow the convex portions 405 to be inserted therein. The openings 406 are sized to ensure sufficient clearance so that the mask 403 and the convex portions 405 are kept out of contact. The convex portions 405 are arranged closer to the center of the mask than the bonding portions 404 provided on the outer periphery of the mask, and the openings 406 are provided to match the arrangement of the convex portions 405.

[0057] FIG. 15 shows a state in which the convex portions 405 provided on the mask frame 401 are in contact with a substrate 407 held by an electrostatic chuck 408 serving as a substrate holding member. In the state shown in FIG. 14B , when the convex portions 405 are in contact with the substrate 407, the convex portions 405 control the gap between the substrate 407 and the upper surface of the mask frame 401. When an attraction magnet (not shown) descends in this state, the mask 403 is attracted and brought into close contact with the substrate 407, resulting in the state shown in FIG. 15 . In this embodiment, by providing the convex portions 405 on the mask frame 401, which is more easily able to ensure rigidity and flatness than the mask 403, it is easier to control the relative height accuracy of the convex portions 405, and the gap between the substrate 407 and the mask 403 can be controlled with higher accuracy. Furthermore, by providing the openings 406 in the mask 403, the convex portions 405 do not contact the mask 403 and therefore do not hinder deformation of the mask 403. This allows the mask 403 to be adsorbed onto the substrate 407 without impairing the alignment accuracy between the mask 403 and the substrate 407 that is performed before the mask 403 is sucked.

[0058] Although this embodiment shows a configuration in which the convex portions are provided on the mask frame 401, a configuration in which the convex portions are provided on the substrate 407 or the electrostatic chuck 408 can also be adopted. In this case, the mask 403 should also be provided with an opening that does not come into contact with the convex portions and that is configured to allow the convex portions to be inserted. If such a configuration is adopted, the convex portions will come into contact with the mask frame 401 without coming into contact with the mask 403. Even when such a configuration is adopted, the same effects as those of this embodiment can be obtained.

[0059] In Examples 1 and 2, the number of protrusions is set to three, so that the contact points between the substrate and the mask frame are reproduced on a single plane. This makes it possible to control the gap between the substrate and the mask with high precision. However, when a configuration is adopted in which the substrate and the mask frame are subject to large deformation due to their own weight, it is not necessary to provide three protrusions; four or more protrusions may be provided to suppress the loss of flatness of the substrate and the mask frame due to deformation due to their own weight.

[0060] <Method for Manufacturing Electronic Device> An example of a method for manufacturing an electronic device using the film forming apparatus 1 according to each of the above embodiments will be described. Below, the configuration and manufacturing method of an organic EL display device will be illustrated as an example of an electronic device. First, the organic EL display device to be manufactured will be described. Fig. 16(a) is an overall view of an organic EL display device 560, and Fig. 16(b) shows the cross-sectional structure of one pixel.

[0061] As shown in FIG. 16( a), a display area 561 of an organic EL display device 560 includes a plurality of pixels 562 arranged in a matrix, each pixel including a plurality of light-emitting elements. As will be described in detail later, each light-emitting element has a structure including an organic layer sandwiched between a pair of electrodes. Note that the term "pixel" as used herein refers to the smallest unit capable of displaying a desired color in the display area 561. In the organic EL display device according to this embodiment, each pixel 562 is configured by a combination of a first light-emitting element 562R, a second light-emitting element 562G, and a third light-emitting element 562B, which emit light different from one another. While the pixel 562 is often configured by a combination of red, green, and blue light-emitting elements, it may also be configured by a combination of yellow, cyan, and white light-emitting elements, and is not particularly limited as long as it emits at least one color.

[0062] 16(b) is a partial cross-sectional schematic diagram taken along line A-B in FIG. 16(a). A pixel 562 includes an organic EL element on a substrate 563, the organic EL element including a first electrode (anode) 564, a hole transport layer 565, one of light-emitting layers 566R, 566G, and 566B, an electron transport layer 567, and a second electrode (cathode) 568. Of these, the hole transport layer 565, the light-emitting layers 566R, 566G, and 566B, and the electron transport layer 567 correspond to organic layers. In this embodiment, the light-emitting layer 566R is an organic EL layer that emits red light, the light-emitting layer 566G is an organic EL layer that emits green light, and the light-emitting layer 566B is an organic EL layer that emits blue light. The light-emitting layers 566R, 566G, and 566B are formed in patterns corresponding to light-emitting elements (sometimes referred to as organic EL elements) that emit red, green, and blue light, respectively. Furthermore, the first electrode 564 is formed separately for each light-emitting element. The hole transport layer 565, the electron transport layer 567, and the second electrode 568 may be formed in common with the plurality of light-emitting elements 562R, 562G, and 562B, or may be formed for each light-emitting element. Note that an insulating layer 569 is provided between the first electrodes 564 to prevent short-circuiting between the first electrode 564 and the second electrode 568 due to foreign matter. Furthermore, because the organic EL layer deteriorates due to moisture and oxygen, a protective layer 570 is provided to protect the organic EL element from moisture and oxygen.

[0063] 16(b), the hole transport layer 565 and the electron transport layer 567 are shown as a single layer, but they may be formed of multiple layers including a hole blocking layer and an electron blocking layer depending on the structure of the organic EL display element. Furthermore, a hole injection layer having an energy band structure that can smoothly inject holes from the first electrode 564 to the hole transport layer 565 can also be formed between the first electrode 564 and the hole transport layer 565. Similarly, an electron injection layer can also be formed between the second electrode 568 and the electron transport layer 567.

[0064] Next, an example of a method for manufacturing an organic EL display device will be specifically described. First, a circuit (not shown) for driving the organic EL display device and a substrate 563 on which a first electrode 564 is formed are prepared.

[0065] An acrylic resin is formed by spin coating on the substrate 563 on which the first electrode 564 is formed, and the acrylic resin is patterned by lithography so as to form an opening in the portion where the first electrode 564 is formed, thereby forming an insulating layer 569. This opening corresponds to the light-emitting region where the light-emitting element actually emits light.

[0066] The substrate 563 with the patterned insulating layer 569 is carried into a first film forming apparatus, and the substrate is held by a substrate support unit. A hole transport layer 565 is formed as a common layer on the first electrode 564 in the display region. The hole transport layer 565 is formed by vacuum deposition. In practice, the hole transport layer 565 is formed to be larger than the display region 561, so a high-resolution mask is not required.

[0067] Next, the substrate 563 on which the hole transport layer 565 has been formed is carried into a second film formation apparatus and held by a substrate support unit. The substrate and a mask are aligned (first alignment and second alignment), the substrate is placed on the mask, and a red light-emitting layer 566R is formed on the portion of the substrate 563 where the red light-emitting element is to be disposed.

[0068] Similar to the formation of the light-emitting layer 566R, a green-emitting light-emitting layer 566G is formed by a third film formation apparatus, and then a blue-emitting light-emitting layer 566B is formed by a fourth film formation apparatus. After the formation of the light-emitting layers 566R, 566G, and 566B is completed, an electron transport layer 567 is formed over the entire display region 561 by a fifth film formation apparatus. The electron transport layer 567 is formed as a layer common to the three-color light-emitting layers 566R, 566G, and 566B.

[0069] The substrate on which the electron transport layer 567 has been formed is transferred to a sputtering device, where a second electrode 568 is formed, and then transferred to a plasma CVD device, where a protective layer 570 is formed, thereby completing the organic EL display device 560 .

[0070] If the substrate 563 on which the insulating layer 569 has been patterned is exposed to an atmosphere containing moisture or oxygen from the time it is carried into the film-forming apparatus until the completion of the formation of the protective layer 570, the light-emitting layer made of an organic EL material may be deteriorated by the moisture or oxygen. Therefore, in this example, the substrate is carried in and out of the film-forming apparatus in a vacuum atmosphere or an inert gas atmosphere.

[0071] 1: Film forming apparatus 2: Magnetic levitation stage 5: Evaporation source 6: Stage support 15: Mask frame 16: Mask 18: Attractive magnet 18X: Lifting mechanism 25: Electrostatic chuck 27: Substrate 31: Stage frame 33: Mask table 35: Control unit 100: Spherical seat 101: Convex portion 110: V-groove portion 401: Mask frame 402: Spherical seat 403: Mask 405: Convex portion 406: Opening 407: Substrate 408: Electrostatic chuck G: Center of gravity

Claims

1. A film forming apparatus for forming a thin film on a substrate held by a substrate holding member through a mask held by a mask holding member placed on a mask stage by a film forming material released from a film forming source in a chamber, wherein the mask stage and the mask holding member are positioned by fitting of a kinematic coupling, and any one of the mask, the mask holding member, the substrate, and the substrate holding member is provided with a convex portion that is pressed when the mask holding member is positioned on the mask stage.

2. The film forming apparatus according to claim 1, further comprising a stage for moving the substrate holding member to perform relative position adjustment between the substrate and the mask, and wherein following control for fitting the kinematic coupling is performed by pressing the convex portion as the stage moves.

3. The film forming apparatus according to claim 2, wherein the fitting state of the kinematic coupling is determined based on the position of the stage during the following control.

4. The film forming apparatus according to claim 2, wherein in the following control, a thrust command based on the speed of the stage is performed, and feedback control for adding a predetermined force to the thrust command is performed.

5. The film forming apparatus according to claim 2, further comprising a magnet for sucking the mask through the substrate, and a lifting mechanism for lifting and lowering the magnet, and wherein when the mask is sucked by the magnet, the force for bringing the substrate and the mask into contact by the stage is changed according to the position of the magnet lifted and lowered by the lifting mechanism.

6. The film forming apparatus according to claim 5, wherein the relationship between the position of the magnet and the contact force between the substrate and the mask is stored in advance, and the force for bringing the substrate and the mask into contact by the stage is changed based on the relationship.

7. The film forming apparatus according to claim 1, wherein the convex portion is arranged at a position offset toward the center of gravity side of the mask from the fitting portion of the kinematic coupling.

8. The fitting portion of the kinematic coupling is provided on one of the mask stage and the mask holding member, and includes a groove portion having a pair of side surfaces whose distance from each other narrows as it approaches the groove bottom, and a hemispherical portion provided on the other. When viewed in the direction perpendicular to the surface of the mask, the convex portion is disposed within a triangular region connecting both ends on the center-of-gravity side of the mask and the center of gravity at both ends in the groove width direction of the pair of side surfaces. The film forming apparatus according to claim 1, characterized in that.

9. The film forming apparatus according to claim 8, characterized in that the center of gravity of the mask and the convex portion are aligned on a straight line where the pair of side surfaces intersect.

10. The convex portion is provided on any one of the mask holding member, the substrate, and the substrate holding member, and the mask is provided with an opening that does not contact the convex portion and is configured such that the convex portion can be inserted. The film forming apparatus according to claim 1, characterized in that.

11. A film forming method for forming a thin film on a substrate held by a substrate holding member through a mask held by a mask holding member placed on a mask stage by a film forming material released from a film forming source in a chamber, wherein the mask stage and the mask holding member are configured to be positionable by fitting of a kinematic coupling, and when the mask holding member is positioned on the mask stage, a pressing step of pressing a convex portion provided on any one of the mask, the mask holding member, the substrate, and the substrate holding member; and a film forming step of forming a thin film on the substrate through the mask. The film forming method characterized by including.

12. The film forming method according to claim 11, characterized in that, by moving a stage that performs relative position adjustment between the substrate and the mask, pressing the convex portion when positioning the mask holding member on the mask stage, and performing tracing control for fitting the kinematic coupling.

13. The film forming method according to claim 12, characterized in that, during the tracing control, the fitting state of the kinematic coupling is determined based on the position of the stage.

14. The film forming method according to claim 12, characterized in that, in the tracing control, a thrust command based on the speed of the stage is performed, and feedback control of adding a predetermined force to the thrust command is performed.

15. A magnet for sucking the mask through the substrate and a lifting mechanism for lifting and lowering the magnet are used. When sucking the mask by the magnet, the force for bringing the substrate and the mask into contact with each other by the stage is changed according to the position of the magnet lifted and lowered by the lifting mechanism. The film forming method according to claim 12, characterized in that.

16. A method for manufacturing an electronic device, characterized in that the film forming method according to any one of claims 11 to 15 is used to manufacture the electronic device.

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