Alignment device

Abstract

The present application provides a technique for improving the detection possibility of marks in alignment of a substrate and a mask. The present application relates to an alignment device provided with: an alignment mechanism that performs alignment of a substrate to be deposited and a mask; a detection mechanism that detects a photographed alignment mark based on image data obtained by photographing at least either one of an alignment mark provided to the substrate and an alignment mark provided to the mask; and a determination mechanism that determines whether or not the detection of the alignment mark performed by the detection mechanism is good, the detection mechanism performing detection of the alignment mark using a first method with respect to the image data, the detection mechanism performing detection of the alignment mark using a second method different from the first method with respect to the image data in a case where the detection of the alignment mark based on the first method is determined by the determination mechanism to be not good.

Description

TECHNICAL FIELD

[0001] The present application relates to an alignment device. BACKGROUND

[0002] Flat panel display devices such as organic EL display devices are widely used. An organic EL display device includes an organic EL element having a functional layer formed with a light emitting layer as an organic layer that causes light emission between two facing electrodes. The functional layer and the electrode layer of the organic EL element are formed by performing film formation of materials that constitute each layer on a substrate such as glass with a mask interposed therebetween in a film formation device.

[0003] An opening having a prescribed pattern is formed on the mask, and when film formation is performed on the substrate, a functional layer, an electrode layer along the shape of the opening pattern is formed. Thus, in order to improve the precision of film formation, it is necessary to align (register) the substrate and the mask with good precision. Conventionally, in the alignment, a method is used in which marks are provided on the substrate and the mask in advance, and the position of the substrate or the mask is adjusted in such a manner that the substrate mark and the mask mark become a prescribed positional relationship within the field of view of a camera.

[0004] Patent Document 1 (Japanese Patent Application Publication No. 2006-073915) discloses a method of detecting positional information based on marks formed on a substrate in a device that transfers a pattern formed on a mask to a substrate. In Patent Document 1, in order to detect the positional information of the marks, pattern matching is performed between a captured image of a camera and a prescribed template.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent Application Publication No. 2006-073915 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In Patent Document 1, the degree of similarity between the captured image and the template is solved using the calculated value of the normalized cross-correlation function, and thus pattern matching is performed, and in the case where the calculated value is less than a prescribed threshold value, it is considered that the pattern has not been detected, and the processing is forcibly ended. However, depending on the kind, material, and state of the substrate and the mask, there are cases where it is difficult to detect the marks. If only the calculated value and the threshold value are simply compared in such a case, the number of cases where it is determined that the marks have not been detected increases, and this can lead to a decrease in the manufacturing efficiency of the film formation device.

[0010] The present application has been made in view of the above problems, and aims to provide a technology for improving the likelihood of detecting marks in the alignment of a substrate and a mask.

[0011] SOLUTION TO THE PROBLEM

[0012] The present application adopts the following structure. That is,

[0013] An alignment device characterized by comprising:

[0014] An alignment mechanism that performs alignment of a substrate that is an object of film formation and a mask;

[0015] A detection mechanism that detects an alignment mark that is photographed based on image data obtained by photographing at least either one of an alignment mark provided to the substrate and an alignment mark provided to the mask; and

[0016] A determination mechanism that determines whether or not the detection of the alignment mark performed by the detection mechanism is good or not,

[0017] The detection mechanism performs detection of the alignment mark using a first method on the image data, and in a case where the detection of the alignment mark based on the first method is determined by the determination mechanism to be not good, the detection mechanism performs detection of the alignment mark using a second method that is different from the first method on the image data.

[0018] Effects of the Invention

[0019] According to the present application, it is possible to provide a technology for improving the detection possibility of a mark in alignment of a substrate and a mask. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic plan view showing the structure of a film formation device.

[0021] Figure 2 is a sectional view showing the structure of an alignment device.

[0022] Figure 3 is a perspective view showing the structure of an alignment device.

[0023] Figure 4 is a view showing the structure of a substrate carrier.

[0024] Figure 5 is a view showing marks of a substrate and a mask.

[0025] Figure 6 is a flowchart showing a process of detecting marks of a substrate and a mask.

[0026] Figure 7 is a view showing a detection process corresponding to the state of a mark.

[0027] Figure 8 is a view showing the structure of an electronic device.

[0028] Explanation of Reference Signs

[0029] 1: alignment device, 5: substrate, 6: mask, 37: substrate mark, 38: mask mark, 60: alignment mechanism, 70: control section DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present application will be described in detail. However, the following embodiments are merely illustrative of the preferred structures of the present application, and do not limit the scope of the present application to these structures. In addition, the hardware structure and software structure of the device, the processing flow, the manufacturing conditions, the dimensions, the materials, the shapes, and the like in the following description are not intended to limit the scope of the present application to these unless otherwise specified.

[0031] The present application is suitable for alignment (positioning) of a substrate and a mask when a thin film of a film formation material is formed on the surface of a substrate or the like by evaporation or sputtering. The present application can be grasped as an alignment device and a control method thereof, an alignment method. The present application can also be grasped as a film formation device and a control method thereof, a film formation method. The present application can also be grasped as a manufacturing device of an electronic device and a control method thereof, a manufacturing method of an electronic device. The present application can also be grasped as a program that causes a computer to execute a control method, a storage medium in which the program is stored. The storage medium can be a non-transitory storage medium that can be read by a computer.

[0032] The present application can be preferably applied to a case where a desired pattern thin film is formed on the surface of a substrate as a film formation target through a mask. As a material of the substrate, any material such as glass, resin, metal, silicon, or the like can be used. As a film formation material, any material such as an organic material, an inorganic material (metal, metal oxide), or the like can be used. Note that, in the following description of the film formation process, "substrate" includes a substrate on which one or more film formation processes have been performed on the surface of the substrate material. The technology of the present application is typically applied to a manufacturing device of an electronic device, an optical member. It is particularly suitable for an organic EL display having an organic EL element, an organic electronic device using the same, and the like. The present application can also be used for a thin film solar cell, an organic CMOS image sensor. However, the application target of the present application is not limited to this, and can be widely used for a device that aligns a substrate and a mask.

[0033] [EMBODIMENT]

[0034] < Film Formation Device >

[0035] Figure 1is a schematic configuration view of a film formation apparatus 300 of a series type for manufacturing an organic EL display according to the present embodiment. An organic EL display is generally manufactured via a circuit element formation process of forming circuit elements, an organic light emitting element formation process of forming organic light emitting elements on a substrate, and a sealing process of forming a protective layer on the formed organic light emitting layer. The film formation apparatus 300 of the present embodiment mainly performs the organic light emitting element formation process.

[0036] The film formation apparatus 300 has a substrate loading chamber 117, a flipping chamber 111a, a mask loading chamber 90, an alignment chamber 100, a plurality of film formation chambers 110a, 110b, a transfer chamber 112, a mask separation chamber 113, a flipping chamber 111b, a substrate separation chamber 114, a mask transfer chamber 116, and a carrier transfer chamber 115.

[0037] The film formation apparatus 300 also has a transfer mechanism (described later) that transfers the substrate carrier 9. The substrate carrier 9 is transferred along a prescribed transfer path within the respective chambers possessed by the film formation apparatus 300. That is, the substrate carrier 9 is transferred in the order of the substrate loading chamber 117, the flipping chamber 111a, the mask loading chamber 90, the alignment chamber 100, the plurality of film formation chambers 110a, 110b, the transfer chamber 112, the mask separation chamber 113, the flipping chamber 111b, the substrate separation chamber 114, and the carrier transfer chamber 115 as indicated by the dotted line, and then returns to the substrate loading chamber 117 again.

[0038] On the other hand, the mask 6 is transferred in the order of the mask loading chamber 90, the alignment chamber 100, the plurality of film formation chambers 110a, 110b, the transfer chamber 112, the mask separation chamber 113, and the mask transfer chamber 116 as indicated by the dotted line, and then returns to the mask loading chamber 90 again. In this way, the substrate carrier 9 and the mask 6 are each cyclically transferred along a prescribed transfer path.

[0039] The substrate 5 is loaded into the substrate loading chamber 117 and mounted to the substrate carrier 9. Specifically, the substrate 5 is loaded into the substrate loading chamber 117 in a state in which the film formation surface faces the upper side in the vertical direction. In the substrate loading chamber 117, the substrate carrier 9 is arranged in a state in which the holding surface faces the upper side in the vertical direction. The substrate 5 loaded into the substrate loading chamber 117 is held by the substrate carrier 9 with being placed on the holding surface of the substrate carrier 9.

[0040] The substrate carrier 9 holding the substrate 5 is moved to the turn-over chamber 111a. Here, a turn-over mechanism 120a, 120b that turns over the substrate holding surface of the substrate carrier 9 from the upward side of the vertical direction to the downward side of the vertical direction or from the downward side of the vertical direction to the upward side of the vertical direction is provided in the turn-over chambers 111a, 111b. As the turn-over mechanism 120a, 120b, a known mechanism that can change the posture (orientation) by gripping or the like of the substrate carrier 9 can be appropriately adopted. By the action of the turn-over mechanism 120a, the substrate carrier 9 is turned over together with the substrate 5 to become a state in which the film-formed surface of the substrate 5 faces the downward side of the vertical direction.

[0041] On the other hand, after the film formation on the substrate 5 described later is completed, when the substrate carrier 9 is carried into the turn-over chamber 111b from the mask separation chamber 113, it is carried in a state in which the film-formed surface of the substrate 5 faces the downward side of the vertical direction. Therefore, the turn-over mechanism 120b turns over the substrate carrier 9 together with the substrate 5 to become a state in which the film-formed surface of the substrate 5 faces the upward side of the vertical direction.

[0042] The substrate carrier 9 is carried into the mask carrying-in chamber 90 through the turn-over in the turn-over chamber 111a. At the same time, the mask 6 is also carried into the mask carrying-in chamber 90. Then, the substrate carrier 9 holding the substrate 5 and the mask 6 are carried into the alignment chamber 100.

[0043] The alignment device 1 is mounted in the alignment chamber 100. The alignment device 1 aligns the substrate carrier 9 (and the substrate 5 held thereby) with the mask 6 and places the substrate carrier 9 (substrate 5) on the mask 6. The alignment device 1 thereafter hands over the mask 6 on which the substrate carrier 9 is placed to the carrying roller 15 and starts carrying toward the next process. As shown in FIG. 1, the carrying roller 15 as a carrying mechanism is arranged in multiple on both sides of the carrying path in the carrying direction, and rotates respectively under the action of the driving force of an unillustrated AC servo motor, thereby carrying the substrate carrier 9 and the mask 6. Note that a speed adjustment chamber that adjusts the speed of the substrate carrier 9 can be provided between the alignment chamber 100 and the film formation chamber 110a, and between the film formation chambers 110a and 110b. By the speed adjustment, a plurality of substrate carriers 9 are carried at a prescribed interval in the film formation chamber 110. Figure 2 、 Figure 3

[0044] ​An evaporation source 7 (film forming mechanism) which discharges an evaporation material toward the upper side in the vertical direction is provided in the film forming chamber 110. The substrate 5 held by the substrate carrier and carried into the film forming chamber 110 in a state where the film forming surface faces the lower side in the vertical direction is passed over the evaporation source 7, whereby the film forming surface except for the portion shielded by the mask 6 is subjected to film formation. The inside of the chamber of the film forming chamber 110 is adjusted in internal pressure by a vacuum pump, a chamber pressure control unit (not shown) provided with a chamber pressure gauge. The evaporation source 7 is provided with a material housing portion such as a crucible which houses the evaporation material, and a heating mechanism such as a sheath heater which heats the evaporation material. Note that the evaporation source 7 can also be provided with a mechanism which moves the material housing portion in a plane substantially parallel to the substrate carrier 9 (substrate 5) and the mask 6, and a mechanism which moves the entire evaporation source.

[0045] After the film formation in the film forming chamber 110 is completed, the substrate carrier 9 and the mask 6 reach the mask separation chamber 113 and are separated from each other in the mask separation chamber 113. The mask 6 separated from the substrate carrier 9 is carried to the mask carrying chamber 116 and is transferred to the film forming process of a new substrate 5. Note that a mask storage device can also be provided in the mask carrying chamber 116 to perform storage of a plurality of masks 6 circulating within the film forming apparatus, and selective carrying-out of the mask corresponding to the substrate carrier 9.

[0046] On the other hand, the substrate carrier 9 holding the substrate 5 is inverted upside down in the inversion chamber 111b after being separated from the mask 6 and is carried to the substrate separation chamber 114. In the substrate separation chamber 114, the substrate 5 after the film formation is separated from the substrate carrier 9 and is carried out from the film forming apparatus 300. The substrate carrier 9 is carried to the substrate carrying-in chamber 117 via the carrier carrying chamber 115 for holding of a new substrate 5.

[0047] Note that the present application is not limited to the upward deposition structure (structure in which the film forming surface of the substrate 5 faces the lower side in the vertical direction at the time of film formation) as in the present embodiment. It can also be a downward deposition structure (structure in which the film forming surface of the substrate 5 faces the upper side in the vertical direction at the time of film formation), or a side deposition structure (structure in which the substrate 5 is vertically erected at the time of film formation).

[0048] In addition, the present application can be not only the structure in which the substrate carrier 9 is placed on the mask 6, or the structure in which the mask 6 is placed on the substrate carrier 9, but also any structure in which the substrate carrier 9 and the mask 6 are positionally adjusted to be stacked. For example, it can also be a structure in which the substrate carrier is not provided and the substrate is directly carried and placed on the mask.

[0049] In addition, the present application can be applied not only to the film formation apparatus of the series type described above, but also to a group type film formation apparatus in which a plurality of film formation chambers, mask stockers, and the like are arranged in groups around a transfer chamber, and a substrate is transferred between the chambers by a robot and film formation is performed at the same time.

[0050] (Substrate carrier)

[0051] The structure of the substrate carrier 9 will be described. Figure 4 (a) of FIG. 9 is a schematic plan view of the substrate carrier 9. Figure 4 (b) of FIG. 9 is a schematic sectional view taken along the line A-A of (a) of FIG. 9. Figure 4 (a) of FIG. 9 is a schematic sectional view taken along the line A-A of (a) of FIG. 9, showing a state in which the substrate holding surface faces upward (front direction of the paper surface). The substrate carrier 9 is a structure having a substantially rectangular planar shape in plan view.

[0052] When the substrate carrier 9 is transferred, the two opposite sides of the four sides of the substrate carrier 9 along the transfer direction are supported by the transfer rollers 15. The transfer rollers 15 are composed of a plurality of transfer rotating bodies arranged on both sides of the transfer path of the substrate carrier 9. The substrate carrier 9 is moved while being guided in the transfer direction by the rotation of the transfer rollers 15.

[0053] The substrate carrier 9 has a rectangular planar member, i.e., a carrier panel 30, a plurality of chuck members 32, and a plurality of support bodies 33. The substrate carrier 9 holds the substrate 5 to the holding surface 31 of the carrier panel 30. In the drawings, a broken line corresponding to the outer edge of the substrate 5 when the substrate 5 is held is shown for ease of understanding. The area inside the broken line is also referred to as a substrate holding portion, and the area outside the broken line is also referred to as a peripheral portion. The substrate holding portion and the peripheral portion are terms defined for ease of understanding, and there can be no structural difference between the two.

[0054] The chuck member 32 is a protrusion having a chucking surface that chucks the substrate 5. The chucking surface is composed of an adhesive member (PSC: Physical Sticky Chucking), and the substrate 5 is held by physical adhesion and suction. The plurality of chuck members 32 respectively chuck the substrate 5, whereby the substrate 5 is held along the holding surface 31 of the carrier panel 30. The plurality of chuck members 32 are respectively arranged so that the chucking surfaces protrude from the holding surface 31 of the carrier panel 30 at a prescribed distance.

[0055] The chuck member 32 is preferably arranged in accordance with the shape of the mask 6, and more preferably arranged in correspondence with the boundary portion (part of the frame edge) of the mask 6 for dividing the film formation region of the substrate 5. Thereby, it is possible to suppress the influence on the temperature distribution of the film formation region of the substrate 5 due to the contact of the chuck member 32 with the substrate 5. In addition, the chuck member 32 is preferably arranged outside the effective display region of the display. This is because the stress generated by the adsorption of the chuck member 32 is feared to deform the substrate 5 or to have an influence on the temperature distribution at the time of film formation.

[0056] When the substrate carrier 9 is turned upside down with the holding surface 31 of the carrier panel 30 holding the substrate 5 facing downward and placed on the mask 6, the support body 33 supports the substrate carrier 9 to the mask 6. Note that, although the support body 33 is configured as a protruding portion from the holding surface 31 of the carrier panel 30, it can also be a structure that makes the entire substrate 5 adhere to the mask 6 after being turned upside down. It can also be a structure in which the support body 33 supports the substrate carrier 9 in such a manner that the substrate 5 held by the substrate carrier 9 is separated from the mask 6 at least in the vicinity of the support body 33.

[0057] Note that the structure of the substrate carrier 9 for holding the substrate 5 is not limited to the chuck member 32. For example, a substrate carrier 9 provided with a support portion that structurally supports the substrate 5 from below at the time of turning upside down can also be used. Alternatively, an electrostatic chuck that holds the substrate 5 by electrostatic force generated by applying voltage to an electrode provided inside the carrier panel 30 can also be used. In addition, a clamping mechanism that clamps the substrate 5 and the mask 6 together can also be used.

[0058] (Alignment device)

[0059] Figure 2 is a schematic cross-sectional view showing the structure of the alignment device 1 for performing alignment, and Figure 1 corresponds to the BB of

[0060] The alignment device 1 is provided with a chamber 4 that maintains the inside in a vacuum atmosphere or a non-reactive gas atmosphere. The chamber 4 has an upper partition wall 4a, a side wall 4b, and a bottom wall 4c. An alignment mechanism 60 (alignment mechanism) that drives the substrate carrier 9 to be brought into register with the position of the mask 6 is arranged above the upper partition wall 4a. By arranging the alignment mechanism 60 including many movable portions outside the chamber, it is possible to suppress the generation of dust inside the chamber. The alignment device 1 also has a carrier support portion 8 that holds the substrate carrier 9, a mask receiving table 16 that holds the mask 6, and a conveyance roller 15. Note that the alignment chamber 100 itself can be the chamber 4, or a chamber 4 can be further arranged inside the alignment chamber 100.

[0061] The alignment mechanism 60 changes the relative positional relationship of the substrate carrier 9 (substrate 5) and the mask 6 or stably holds the substrate carrier 9 (substrate 5) and the mask 6 while maintaining the positional relationship. The alignment mechanism 60 includes an in-plane movement mechanism 11, a Z-lift base 13, and a Z-lift slide 10. The in-plane movement mechanism 11 is connected to the upper partition wall 4a of the chamber 4 and drives the Z-lift base 13 in the XYθ direction. The Z-lift base 13 is connected to the in-plane movement mechanism 11 and serves as a base when the substrate carrier 9 moves in the Z direction. The Z-lift slide 10 is a member that can move in the Z direction along the Z guide 18 (18a to 18d). The Z-lift slide is connected to the carrier support portion 8 via the carrier holding shaft 12.

[0062] When the substrate carrier 9 (substrate 5) is moved in the XYθ direction in a plane parallel to the substrate 5, the Z-lift base 13, the Z-lift slide 10, and the carrier holding shaft 12 are driven as a unit and transmit the driving force to the carrier support portion 8. As the in-plane movement mechanism 11 for achieving this, for example, a plurality of driving units that generate driving forces in different directions from each other can be used. By the driving units, driving forces corresponding to the movement amounts are generated, and the position of the Z-lift base 13 in the XYθ direction can be controlled.

[0063] In addition, when the substrate carrier 9 (substrate 5) is moved in the Z direction, the Z-lift slide 10 is driven in the Z direction with respect to the Z-lift base 13. At this time, the driving force is transmitted to the carrier support portion 8 via the carrier holding shaft 12 (12a to 12d). In this way, the Z-lift slide and the like function as a distance changing mechanism, and as a result, the relative distance between the substrate carrier 9 and the mask 6 changes.

[0064] Note that the structure in which the alignment mechanism 60 moves the substrate 5 is not limited to the embodiment, and the structure in which the alignment mechanism 60 moves the mask 6 or the structure in which both the substrate 5 and the mask 6 are moved can be used. That is, the alignment mechanism 60 is a mechanism that adjusts the relative position of the substrate 5 and the mask 6 by moving at least one of the substrate 5 and the mask 6.

[0065] Figure 3 is a perspective view showing a scheme of the alignment device 1. The mask receiving stage 16 is raised and lowered along the lift stage guide 34 placed on the mask stage base 19. In addition, the handling roller 15 is placed at the lower portion along the edge in the handling direction of the mask 6, and the mask 6 is handed over to the handling roller 15 by lowering the mask receiving stage 16. The mask used for the production of, for example, an organic EL display has a structure in which the mask foil 6b having an opening corresponding to a film formation pattern is fixed in a state of being stretched on the mask frame 6a having high rigidity. By this structure, the mask receiving portion can be held in a state of reducing the deflection of the mask foil 6b.

[0066] The carrier holding shaft 12 is provided through a through-hole provided in the upper partition wall 4a of the chamber 4, and extends outside and inside the chamber 4. A carrier support portion 8 is provided in the lower portion of the carrier holding shaft 12, and a substrate 5 can be held via a substrate carrier 9. The portion of the carrier holding shaft 12 from the through-hole to the fixed portion fixed to the Z-lift slider 10 (the portion above the through-hole) is covered by a bellows 40 fixed to the Z-lift slider 10 and the upper partition wall 4a. Thus, the carrier holding shaft 12 as a whole can be maintained in the same vacuum state as the film formation space 2.

[0067] Four Z guides 18a to 18d for guiding the Z-lift slider 10 in the vertical Z direction are fixed to the side surface of the Z-lift base 13. A ball screw 27 disposed in the center of the Z-lift slider 10 transmits a driving force from a motor 26 fixed to the Z-lift base 13 to the Z-lift slider 10. The Z-direction position of the Z-lift slider 10 can be measured from the rotation speed of a not-shown rotary encoder built in the motor 26. Note that the lift mechanism of the Z-lift slider 10 is not limited to the ball screw 27 and the rotary encoder, and any mechanism such as a combination of a linear motor and a linear encoder can be used.

[0068] The various operations performed by the alignment device 1 (alignment by the in-plane movement mechanism 11, lifting of the Z-lift slider 10, holding of the substrate by the carrier support portion 8, evaporation by the evaporation source 7, and the like) are controlled by a control portion 70. The control portion 70 can be constituted by a computer having a processor, a memory, a storage, an I / O, and the like, for example. In this case, the functions of the control portion 70 are realized by the processor executing a program stored in the memory or the storage. As the computer, a general-purpose personal computer can be used, or an embedded computer or a PLC (programmable logic controller) can be used. Alternatively, a part or all of the functions of the control portion 70 can be constituted by an ASIC or an FPGA.

[0069] The control portion 70 can be provided for each chamber of the film formation device 300, or one control portion 70 can control a plurality of chambers or the entire film formation device. The storage portion 71 is a memory for storing and reading out information by the control portion 70. As the storage portion 71, a built-in memory of the control portion 70 can be used.

[0070] An imaging device 14 (14a-14d) is used to detect the positions of the substrate 5 and the mask 6 during alignment. The imaging device 14 is disposed on the outer side of the upper partition wall 4a of the chamber 4 to acquire the positions of alignment marks on the mask 6 and the substrate 5. A through-hole for imaging is provided on the camera optical axis of the imaging device 14 in the upper partition wall 4a, allowing the imaging device 14 to image the interior of the chamber. A window glass 17 (17a-17d) is embedded in the through-hole for imaging to maintain the air pressure inside the chamber.

[0071] (Mask structure)

[0072] like Figure 5 As shown in (b), the mask 6 has a structure in which a mask foil 6b with a thickness of a few μm to tens of μm is welded and fixed to a frame-shaped mask frame 6a. The mask frame 6a supports the mask foil 6b in a state of being pulled in its surface direction to prevent the mask foil 6b from deflecting. The mask foil 6b includes a boundary portion for dividing the film-forming area of ​​the substrate. The boundary portion of the mask foil 6b is in close contact with the substrate 5 when the mask 6 is assembled to the substrate 5 to block the film-forming material. It should be noted that the mask 6 can be an open mask in which the mask foil 6b only has a boundary portion, or it can be a fine mask in which fine openings corresponding to pixels or sub-pixels are formed in the portion other than the boundary portion, that is, in the portion corresponding to the film-forming area of ​​the substrate. When using a glass substrate or a substrate on which a film made of resin such as polyimide is formed on a glass substrate as the substrate 5, an iron alloy can be used as the main material for the mask frame 6a and the mask foil 6b, and an iron alloy containing nickel is preferred.

[0073] Alternatively, the mask 6 that serves as the alignment target of this invention can also be a specific mask not used during film formation on the product. Such a specific mask is made to be the same size as the ordinary mask 6, so that it can be transported by the transport roller 15 and aligned by the alignment device 1 in the same way as the ordinary mask 6, and has mask markings arranged in the same positions as the ordinary mask 6. As an example of a specific mask, sometimes a box-shaped mask made of aluminum or the like is used to confirm the performance and deposition state related to the vapor deposition of the film formation apparatus 300. This specific mask has a blocking member that can be opened and closed in a part of the box, and the film formation state, such as film thickness, can be confirmed by opening and closing the blocking member at any time during passage through the film formation chamber 110. Specifically, the substrate markings on the substrate 5 and the mask markings on the specific mask are aligned, and the specific mask is passed over a specific film formation source within the film formation chamber 110 with the blocking member open, thereby confirming the state and performance of the film formation source.

[0074] According to the inventor's research, such specific masks have problems with material or usage characteristics and processing precision, and are prone to damage, resulting in frequent damage and discoloration of the markings. When the markings are damaged or discolored, it is difficult to detect them from the captured image, leading to marking detection errors. Therefore, the inventor has researched a marking detection method based on captured images that does not cause detection errors even when the markings become blurred or discolored due to damage, making detection difficult. However, the application of this invention is not limited to specific masks, but can also be applied to the detection of mask markings on a general mask 6 and substrate markings on a substrate 5. Therefore, in the following description, the alignment of the mask marking 38 (mask alignment mark) on a general mask 6 and the substrate marking 37 (substrate alignment mark) on a substrate 5 will be described.

[0075] (alignment)

[0076] Reference Figure 5 (a)~ Figure 5 (c) describes a method for measuring the positions of substrate mark 37 and mask mark 38 using camera device 14. Figure 5 (a) is a view from above of the substrate 5 on the carrier panel 30, held in place by the carrier support 8. For illustration, the carrier panel 30 is shown in perspective with dashed lines. Substrate marks 37a to 37d are formed at the four corners of the substrate 5. Imaging devices 14a to 14d simultaneously measure the substrate marks 37a to 37d. The control unit 70 calculates the X-direction movement, Y-direction movement, and rotation of the substrate 5 based on the positional relationship of the four points, including the center positions of each substrate mark 37a to 37d, thereby obtaining the position information of the substrate 5. The substrate marks 37 may, for example, be a component containing a metallic material provided on the substrate 5.

[0077] Figure 5 (b) is a view of the mask frame 6a from above, which has mask marks 38a to 38d formed at its four corners. Cameras 14a to 14d simultaneously measure the mask marks 38a to 38d. The control unit 70 calculates the X-direction movement, Y-direction movement, and rotation of the mask 6 based on the positional relationship of these four points (the center positions of each mask mark 38a to 38d), thereby obtaining the positional information of the mask 6. The mask marks 38 may, for example, be openings provided on a component of the mask 6 that contains metallic material.

[0078] Figure 5(c) is a diagram schematically showing a field of view 44 of a captured image when one of the four groups of mask marks 38 and substrate marks 37 is measured using the imaging device 14. In this example, within the field of view 44 of the imaging device 14, since the substrate mark 37 and the mask mark 38 are measured at the same time, the relative positions of the mark centers to each other can be determined. Note that the shapes of the mask marks 38 and the substrate marks 37 are not limited to the illustrated examples, but are preferably shapes having symmetry that make it easy to calculate the center positions.

[0079] In the case where high-precision alignment is required, as the imaging device 14, a high-magnification CCD camera having a high resolution of the order of several μm is used. In the case of such a high-magnification CCD camera, since the field of view diameter is several mm or less, if the positional deviation when the substrate carrier 9 is placed on the carrier receiving jaws is large, the substrate marks 37 can deviate from the field of view and cannot be measured. Therefore, as the imaging device 14, a low-magnification CCD camera having a large field of view is provided in addition to the high-magnification CCD camera. In this case, two-stage alignment can be performed. That is, after roughly aligning (coarse alignment) using the low-magnification CCD camera in such a manner that the mask marks 38 and the substrate marks 37 fall within the field of view of the high-magnification CCD camera at the same time, high-precision alignment (fine alignment) is performed by using the high-magnification CCD camera to measure the positions of the mask marks 38 and the substrate marks 37.

[0080] The control section 70 performs mark detection based on image processing using a captured image that has been digitized as a pixel value for each pixel as a target. The control section 70 of the present embodiment can execute both of the two kinds of image processing methods, a normalized cross-correlation method and a shape-based matching method, and continues processing according to the detection results (described later). The control section 70 can acquire relative position information of the mask frame 6a and the substrate 5 from the position information of the mask frame 6a and the position information of the substrate 5 acquired by the imaging device 14. This relative position information is fed back to the control section 70 of the alignment device to control the drive amounts of each of the drive sections, the Z-lift slide 10, the in-plane movement mechanism 11, the carrier support section 8, and the like.

[0081] The alignment device 1 aligns the substrate 5 on the substrate carrier 9 with the mask 6 and places the substrate carrier 9 (substrate 5) on the mask 6. At this time, first, the substrate carrier 9 is carried into the chamber 4 and placed on the carrier receiving jaws on both sides of the carrier support section 8.

[0082] Next, the alignment device 1 lowers the substrate carrier 9 and moves to an alignment height. Also, the imaging device 14 takes a shot to acquire position information of the substrate mark 37 and the mask mark 38. The control section 70 performs in-plane movement of the substrate carrier 9 and the shot until the substrate mark 37 and the mask mark 38 are in a range where a prescribed positional relationship is established. The control section 70 determines that in-plane alignment is complete when the positional offset of the substrate 5 and the mask 6 becomes equal to or less than a prescribed threshold value, based on the shot image of the alignment mark. Also, by relatively moving the substrate carrier 9 and the mask 6 in a direction perpendicular to the substrate surface and placing the substrate carrier 9 on the mask 6, the substrate 5 and the mask 6 are brought into close contact.

[0083] (Processing of mark detection)

[0084] Reference Figure 6 The processing in the mark detection of the alignment device 1 will be described with reference to the flowchart. In this flow, the processing of detecting the substrate mark 37 of the substrate 5 and the mask mark 38 of the mask 6 as a specific mask inside the field of view 44 will be described. Since this specific mask is likely to be damaged or blurred, the processing of this flow is suitable. However, the present application is not limited to this, and a general mask 6 can also be the target. The present application can be used for the processing of either the substrate mark 37 or the mask mark 38.

[0085] This flow is started when the imaging device 14 of the alignment device 1 takes a shot of the mask 6 inside the alignment chamber 100 to acquire image data including the substrate mark 37 and the mask mark 38.

[0086] In step S101, the control section 70 analyzes the image data using template matching (first method) such as the normalized cross-correlation method (NCC) to determine the position (coordinates) of the mask mark in the image. Note that the method of template matching is not limited to the normal cross-correlation method. For example, it can also be the zero-mean normalized cross-correlation method (ZNCC) which is highly adaptive to changes in brightness. Furthermore, any method that can evaluate the degree of similarity between a portion of the shot image data and a template image can be used, such as the sum of squared difference (SSD), the sum of absolute difference (SAD), and the like. The normalized cross-correlation method can accurately identify the degree of coincidence between a template and an image, but on the other hand, it is less resistant to noise and deformation, and the degree of similarity decreases when the mark is damaged, blurred, or missing.

[0087] Here, Figure 7(a) shows the template 381 used for detecting mask mark 38. The control unit 70 causes the template 381 to be applied throughout. Figure 7 The image data, as shown in (b), is moved to all positions, and the correlation coefficient between each position and the template is calculated to determine the similarity. At this point, the image data can be read in using grayscale (e.g., grayscale represented by pixel values ​​from 0 to 255). In the example image, since the position with the highest calculated similarity is the image position with center coordinates (x1, y1) of mask marker 38, this center coordinate is output as the result. It should be noted that the output result is not limited to center coordinates. It can be output in a form that can be used in subsequent alignment processing, such as the coordinates of one or more marked feature points or the coordinates of one or more marked corners.

[0088] Furthermore, even if the control unit 70 determines the image location representing the maximum similarity, it does not immediately output the result. Instead, the control unit 70 compares the detected similarity value with a first threshold (first determination) as shown in step S102. Here, both the first and second thresholds are values ​​compared with the similarity in normalized cross-correlation, and the second threshold is a value smaller than the first threshold. It should be noted that the similarity value varies depending on the algorithm. For example, when the maximum similarity is set to 1.0, the first threshold can be set to 0.9 and the second threshold to 0.8. If the similarity exceeds the first threshold, the control unit 70 determines that the marker detection is successful and proceeds to step S107, outputting the result by outputting the center coordinates. When outputting this result, information indicating that the similarity exceeds the first threshold can also be output. This allows notification that the marker detection accuracy is relatively high. On the other hand, if the similarity is below the first threshold, the process proceeds to step S103.

[0089] Here, the case where the similarity is below the first threshold refers to, for example, Figure 7 As shown in (c), mask mark 38 is blurred due to damage during processing, handling, or storage. Normalized cross-correlation is difficult to detect marks in the presence of blurring or noise, therefore... Figure 7 In case (c), the similarity falls below the first threshold. However, if this case is directly considered a detection error, while the reliability of marker detection can be improved, the probability of marker detection will decrease, and the availability of inspection using a specific mask (or film formation processing using mask 6) will decrease. Therefore, in this process, the threshold is changed for the same captured image to make a second determination, thereby improving the probability of marker detection. Preferably, the second threshold is set to a value that does not affect the reliability of film formation processing and inspection.

[0090] Specifically, the control section 70 compares the degree of similarity with a second threshold value that is smaller than the first threshold value in step S103 (second determination). In a case where the degree of similarity exceeds the second threshold value, it is determined that the template matching is successful, and the process proceeds to step S107, and as a result, the center coordinates are output. At the time of this result output, information indicating that the degree of similarity is below the first threshold value and greater than the second threshold value can also be output. Thus, it is possible to notify that the mark can be detected but the precision is relatively low. On the other hand, in a case where the degree of similarity is below the second threshold value, the detection using the first method is no longer continued, and the process proceeds to step S104. Here, the case where the degree of similarity is below the second threshold value means, for example, a state where the mask mark 38 is blurred above (c) of FIG. 6 and causes a lower degree of similarity as shown in (d) of FIG. 6. Figure 7 Figure 7

[0091] In step S104, the control section 70 analyzes the image data using shape-based matching (second method) to determine the position (coordinates) of the mask mark in the image. The shape-based matching is a pattern matching method using edge information of a model, and determines a position having the same edge as a candidate from the image data and calculates the degree of similarity with the model image based on edge information such as edge points, edge intensity, edge gradient, and the like extracted from the model image using a filter or the like. In the shape-based matching, by extracting information having a feature in geometry such as an edge, the tolerance to noise, deformation of the image due to damage, blur, defect, and the like of the mark is enhanced compared to the normalized cross-correlation method. In addition, it has tolerance to brightness, contrast, and gradation change. In addition, in the shape-based matching, since information of geometry such as a contour is used, it is irrelevant to the color of the mark. Thus, even in a case where discoloration or color inversion occurs on the surface, it is possible to improve the detection possibility.

[0092] For the second method, the control section 70 also compares the degree of similarity with a threshold value in step S105. This threshold value (third threshold value) is different from the first threshold value and the second threshold value, and is a value related to the degree of similarity in the shape-based matching, and the specific set value is a value corresponding to the algorithm. In a case where the degree of similarity exceeds the third threshold value, it is determined that the shape-based matching is successful, and the process proceeds to step S107, and as a result, the center coordinates are output. At the time of this result output, information indicating that the coordinates are acquired using the shape-based matching can also be output. Thus, it is possible to convey to the subsequent process that the mark can be detected but the precision is relatively low.

[0093] ​​On the other hand, when the similarity is below the third threshold value, the control section 70 no longer continues the detection using the second method, proceeds to step S106, and notifies the subsequent process of information that a mark detection error has occurred. The control section 70 displays the information on the display or gives an audio notification that a detection error has occurred, to urge the user to confirm the state of the mask 6.

[0094] Note that in the present flow, it is assumed that the mask mark 38 is present within the field of view 44. However, there is a possibility that the result of S105 becomes "No" due to the mask mark 38 not being present within the field of view 44. Therefore, in the subsequent process receiving the notification of S106, the control section 70 can also perform alignment again instead of notifying the user.

[0095] Note that although this is omitted in the above description, in the present flow, it is assumed that the substrate mark 37 has been detected. Also, when the result of any one of steps S102, S103, and S107 is "Yes", the coordinates of the mask mark 38 and the substrate mark 37 are output to the subsequent process. Thus, the control section 70 can determine whether the positional relationship of the mask mark 38 and the substrate mark 37 is within a prescribed range, and thereby determine the goodness of the alignment.

[0096] In steps S101 and S104 of the present flow, the control section 70 attempts to perform detection of the alignment mark. At this time, the control section 70 functions as a detection mechanism of the mark. Also, in steps S102, S103, and S105, the control section 70 performs goodness determination of the detection result of the alignment mark, and outputs the result when the detection result is good, and changes the threshold value or the conversion method when the detection result is not good. At this time, the control section 70 functions as a determination mechanism that performs goodness determination of the mark detection.

[0097] As described above, according to the present embodiment, a plurality of detection methods are used to perform detection of the mark from the captured image. Thus, the detection possibility of the mark can be improved by combining the features of each detection method. For example, when detecting the mark from the captured image, even when detection cannot be performed using the first method, the detection possibility of the mark is improved by using the second method that performs edge extraction with strong noise tolerance.

[0098] In this process, after using normalized cross-correlation as the first method, shape-based matching is used as the second method. This is because normalized cross-correlation typically offers high reproducibility of the detection location, improving alignment accuracy. Therefore, in this process, multiple thresholds are used to perform normalized cross-correlation. On the other hand, normalized cross-correlation suffers from poor tolerance to image overlap, breaks, defects, and noise, increasing the likelihood of detection errors with easily damaged masks (e.g., specific aluminum masks). Therefore, in this process, shape-based matching, as the second method, further enhances the detection probability. However, the relationship between the first and second methods is not limited to this.

[0099] In the above process, by using two thresholds in the first method, the probability of marker detection based on the same captured image is increased. However, the effects of the present invention can be achieved by combining at least the first method and the second method. Alternatively, three or more thresholds can be used in the first method to increase the number of decision stages. Furthermore, multiple thresholds can also be used in the second method to perform decision-making in stages.

[0100] <Methods for Manufacturing Electronic Devices>

[0101] Next, an example of a method for manufacturing an electronic device using the film-forming apparatus of this embodiment will be described. Hereinafter, as an example of an electronic device, the structure of an organic EL display device will be shown, and a method for manufacturing an organic EL display device will be illustrated.

[0102] First, the organic EL display device to be manufactured will be explained. Figure 8 (a) is an overall view of the organic EL display device 700. Figure 8 (b) represents the cross-sectional structure of a pixel.

[0103] like Figure 8 As shown in (a), in the display area 701 of the organic EL display device 700, a plurality of pixels 702, each equipped with a plurality of light-emitting elements, are arranged in a matrix. Each light-emitting element has a structure having an organic layer held by a pair of electrodes, as will be described in detail later. It should be noted that a pixel, as used here, refers to the smallest unit in the display area 701 capable of displaying a desired color. In the case of the organic EL display device of this embodiment, the pixel 702 is constructed by a combination of a first light-emitting element 702R, a second light-emitting element 702G, and a third light-emitting element 702B that exhibit different light emission. The pixel 702 is mostly composed of a combination of red, green, and blue light-emitting elements, but it can also be a combination of yellow, blue-green, and white light-emitting elements, as long as there is at least one color, there is no particular limitation.

[0104] Figure 8 (b) is Figure 8 A partial cross-sectional view of the B-B line of (a). The 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, any one of a light emitting layer 706R, 706G, 706B, an electron transport layer 707, and a second electrode (cathode) 708 on a substrate 703. Among them, the hole transport layer 705, the light emitting layer 706R, 706G, 706B, and the electron transport layer 707 correspond to the organic layer. In addition, in the present embodiment, the light emitting layer 706R is an organic EL layer that emits red light, the light emitting layer 706G is an organic EL layer that emits green light, and the light emitting layer 706B is an organic EL layer that emits blue light. The light emitting layers 706R, 706G, 706B are formed in patterns corresponding to light emitting elements (sometimes also referred to as organic EL elements) that emit red light, green light, and blue light, respectively.

[0105] In addition, 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 can be formed in common for the plurality of light emitting elements 702R, 702G, 702B, or can be formed for each light emitting element. Note that, in order to prevent the first electrode 704 and the second electrode 708 from short-circuiting due to foreign matter, an insulating layer 709 is provided between the first electrodes 704. Furthermore, since the organic EL layer deteriorates due to moisture and oxygen, a protective layer 710 is provided for protecting the organic EL element from moisture and oxygen.

[0106] In Figure 8 (b), the hole transport layer 705 and the electron transport layer 707 are shown in one layer, but depending on the structure of the organic EL display element, they can be formed by a plurality of layers including a hole blocking layer and an electron blocking layer. In addition, a hole injection layer can be formed between the first electrode 704 and the hole transport layer 705, the hole injection layer having a band structure that enables smooth injection of holes from the first electrode 704 to the hole transport layer 705. Similarly, an electron injection layer can be formed between the second electrode 708 and the electron transport layer 707.

[0107] Next, an example of the manufacturing method of the organic EL display device will be described in detail.

[0108] First, a substrate (mother glass) 703 on which a circuit (not shown) for driving the organic EL display device and the first electrode 704 are formed is prepared.

[0109] An acrylic resin is formed on the substrate 703 on which the first electrode 704 is formed by a spin coating method, and the acrylic resin is patterned by a photolithography method to form an opening in a portion on which the first electrode 704 is formed, thereby forming the insulating layer 709. The opening portion corresponds to a light emitting region in which light is actually emitted from the light emitting element.

[0110] The substrate 703 on which the insulating layer 709 is patterned is placed on a substrate carrier on which an adhesive member is provided. The substrate 703 is held by the adhesive member. The substrate is carried into the first organic material film forming apparatus, and after being flipped, the hole transport layer 705 is formed as a common layer on the first electrode 704 in the display region. The hole transport layer 705 is formed by vacuum evaporation. Actually, since the hole transport layer 705 is formed to have a larger size than the display region 701, a high-precision mask is not required.

[0111] Next, the substrate 703 on which the hole transport layer 705 is formed is carried into the second organic material film forming apparatus. The substrate is aligned with a mask, and the substrate is placed on the mask to form a light emitting layer 706R that emits red light in a portion of the substrate 703 on which an element that emits red light is provided.

[0112] Similarly to the film formation of the light emitting layer 706R, a light emitting layer 706G that emits green light is formed by the third organic material film forming apparatus, and a light emitting layer 706B that emits blue light is further formed by the fourth organic material film forming apparatus. After the film formation of the light emitting layers 706R, 706G, and 706B is completed, an electron transport layer 707 is formed on the entire display region 701 by the fifth film forming apparatus. The electron transport layer 707 is formed as a common layer on the three color light emitting layers 706R, 706G, and 706B.

[0113] The substrate on which the electron transport layer 707 is formed is moved to the metallic evaporation material film forming apparatus to form a second electrode 708.

[0114] After that, the film formation process of the substrate 703 is completed by moving to the plasma CVD apparatus to form a protective layer 710. After being flipped, the adhesive member is peeled from the substrate 703 to separate the substrate 703 from the substrate carrier. After that, the organic EL display device 700 is completed by being cut.

[0115] From the time when the substrate 703 on which the insulating layer 709 is patterned is carried into the film forming apparatus to the time when the film formation of the protective layer 710 is completed, if it is exposed to an atmosphere containing moisture or oxygen, the light emitting layer composed of the organic EL material can be deteriorated by the moisture or oxygen. Therefore, in this example, the carrying-in and carrying-out of the substrate between the film forming apparatuses are performed in a vacuum atmosphere or a non-reactive gas atmosphere.

Claims

1. An alignment device, characterized in that, have: The alignment mechanism aligns the substrate and the mask of the object to be coated. The detection mechanism detects the captured alignment marks based on image data obtained by capturing images of at least one alignment mark disposed on the substrate and an alignment mark disposed on the mask; and The judging body determines the quality of the alignment mark detection performed by the testing body. The detection mechanism performs alignment mark detection on the image data using template matching, and outputs the similarity between the alignment mark and the template. If the similarity is below a predetermined threshold and the alignment mark detection based on template matching is deemed unsatisfactory by the judgment mechanism, the detection mechanism performs alignment mark detection on the image data using shape-based matching.

2. The alignment device according to claim 1, characterized in that, The template matching method is normalized cross-correlation.

3. The alignment device according to claim 1, characterized in that, The determination performed by the determination mechanism includes a first determination and a second determination. The first determination is a determination that the detection of the alignment mark is poor when the similarity is below a first threshold, and the second determination is a determination that the detection of the alignment mark is poor when the similarity is below a second threshold that is smaller than the first threshold.

4. The alignment device according to claim 3, characterized in that, If the determination mechanism determines in the first determination that the detection of the alignment mark is poor, it shall perform the second determination.

5. The alignment device according to claim 4, characterized in that, When the determination mechanism detects the alignment mark using the template matching, it outputs information indicating which of the first and second determinations the alignment mark was detected in.

6. The alignment device according to claim 1, characterized in that, The detection mechanism is able to detect the alignment mark even when the color of the alignment mark is reversed when using the shape-based matching alignment mark.

7. The alignment device according to claim 1, characterized in that, The alignment mark of the substrate is a component containing a metallic material disposed on the substrate, and the alignment mark of the mask is an opening disposed on the component containing the metallic material.

8. The alignment device according to claim 1, characterized in that, The alignment mechanism adjusts the relative position of the substrate and the mask based on information related to the alignment marks of the substrate and the alignment marks of the mask that are determined to be good by the determination mechanism.

9. A film-forming apparatus, characterized in that, have: The alignment device according to any one of claims 1 to 8; and A film-forming mechanism that forms a film on the substrate aligned by the alignment device through the mask.

Images