CN116130395A

CN116130395A - Alignment device

Info

Publication number: CN116130395A
Application number: CN202211367460.9A
Authority: CN
Inventors: 神田宽
Original assignee: Canon Tokki Corp
Current assignee: Canon Tokki Corp
Priority date: 2021-11-12
Filing date: 2022-11-03
Publication date: 2023-05-16
Also published as: JP2023072462A; JP7489368B2; KR20230069822A

Abstract

The present invention provides a technique for improving the detection probability of marks in the alignment of a substrate and a mask. The alignment device according to the present invention comprises: an alignment mechanism for aligning a substrate to be film-formed with a mask; a detection mechanism for detecting the shot alignment mark according to image data obtained by shooting at least any one of the alignment mark arranged on the substrate and the alignment mark arranged on the mask; and a determination means for determining whether or not the detection of the alignment mark by the detection means is good, wherein the detection means detects the alignment mark by a first method on the image data, and wherein the detection means detects the alignment mark by a second method different from the first method on the image data when the detection of the alignment mark by the first method is determined to be bad by the determination means.

Description

Alignment device

Technical Field

The present invention relates to alignment devices.

Background

Flat panel display devices such as organic EL display devices are widely used. The organic EL display device includes an organic EL element formed with a functional layer between two facing electrodes, wherein the functional layer has a light-emitting layer as an organic layer that causes light emission. The functional layer and the electrode layer of the organic EL element are formed by forming a film of a material constituting each layer on a substrate such as glass via a mask in a film forming apparatus.

Openings of a predetermined pattern are formed in the mask, and when film formation is performed on the substrate, a functional layer and an electrode layer are formed along the shape of the opening pattern. Therefore, in order to improve the film formation accuracy, it is necessary to align (align) the substrate and the mask with good accuracy. In general, in alignment, the following method is used: marks are provided on the substrate and the mask in advance, and the position of the substrate or the mask is adjusted so that the substrate mark and the mask mark have a predetermined positional relationship within the field of view of the camera.

Patent document 1 (japanese patent application laid-open No. 2006-073915) discloses a method of detecting positional information based on a mark formed on a substrate in an apparatus for transferring a pattern formed on a mask onto the substrate. In patent document 1, pattern matching is performed between a captured image of a camera and a predetermined template in order to detect position information of a mark.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2006-073915

Disclosure of Invention

Problems to be solved by the invention

In patent document 1, pattern matching is performed by solving the similarity between the captured image and the template using the calculated value of the normalized cross-correlation function, and if the calculated value is smaller than a predetermined threshold value, the processing is forced to end as if no pattern is detected. However, depending on the type, material, and state of the substrate and mask, it may be difficult to detect the mark. In such a case, simply comparing the calculated value with the threshold value may increase the number of cases in which it is determined that the mark is not detected, and may cause a decrease in the manufacturing efficiency of the film forming apparatus.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a technique for improving the possibility of detecting a mark during alignment of a substrate and a mask.

Means for solving the problems

The present invention adopts the following structure. That is to say,

an alignment device, comprising:

an alignment mechanism for aligning a substrate to be film-formed with a mask;

a detection mechanism that detects a captured alignment mark based on image data obtained by capturing at least one of the alignment mark provided on the substrate and the alignment mark provided on the mask; and

a determination means for determining whether or not the alignment mark is detected by the detection means,

the detection means detects the alignment mark using a first method on the image data, and when the detection of the alignment mark based on the first method is determined to be bad by the determination means, the detection means detects the alignment mark using a second method different from the first method on the image data.

Effects of the invention

According to the present invention, a technique for improving the detection probability of a mark in alignment of a substrate and a mask can be provided.

Drawings

Fig. 1 is a schematic plan view showing the structure of a film forming apparatus.

Fig. 2 is a cross-sectional view showing the structure of the alignment device.

Fig. 3 is a perspective view showing the structure of the alignment device.

Fig. 4 is a diagram illustrating a structure of a substrate carrier.

Fig. 5 is a diagram illustrating the marking of the substrate and the mask.

Fig. 6 is a flowchart showing a process of detecting marks of the substrate and the mask.

Fig. 7 is a diagram illustrating detection processing according to the state of the mark.

Fig. 8 is a diagram illustrating the structure of an electronic device.

Description of the reference numerals

1: alignment device, 5: substrate, 6: mask, 37: substrate marking, 38: mask marking, 60: alignment mechanism, 70: control unit

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are merely exemplary embodiments showing preferred configurations of the present invention, and do not limit the scope of the present invention to these configurations. The hardware configuration and software configuration, process flow, manufacturing conditions, dimensions, materials, shapes, and the like of the apparatus described below are not intended to limit the scope of the present invention unless specifically described.

The present invention is suitable for alignment (alignment) of a substrate and a mask when a thin film of a film-forming material is formed on a surface of a film-forming object such as a substrate by vapor deposition or sputtering. The present invention can be grasped as an alignment device, a control method thereof, and an alignment method. The present invention can also be grasped as a film forming apparatus, a control method thereof, and a film forming method. The present invention can also be grasped as an apparatus for manufacturing an electronic device, a method for controlling the same, and a method for manufacturing an electronic device. The present invention can also be grasped as a program for causing a computer to execute a control method, and a storage medium storing the program. The storage medium may be a non-transitory storage medium that can be read by a computer.

The present invention is preferably applicable to a case where a thin film having a desired pattern is formed on a surface of a substrate to be film-formed through a mask. As a material of the substrate, any material such as glass, resin, metal, and silicon can be used. As the film-forming material, any material such as an organic material and an inorganic material (metal, metal oxide) can be used. The term "substrate" in the following description of the film forming step includes a substrate on the surface of which one or more films have been formed on the surface of a substrate material. The technique of the present invention is typically applied to an apparatus for manufacturing an electronic device or an optical member. In particular, the organic EL display device is suitable for organic EL display devices including organic EL elements, organic EL display devices using the organic EL display devices, and the like. The invention can also be used for thin film solar cells and organic CMOS image sensors. However, the application object of the present invention is not limited to this, and can be widely used in an apparatus for aligning a substrate with a mask.

Examples (example)

< film Forming apparatus >)

Fig. 1 is a schematic configuration diagram of a tandem type film forming apparatus 300 for manufacturing an organic EL display according to the present embodiment. The organic EL display is generally manufactured through a circuit element forming process of forming a circuit element, an organic light emitting element forming process of forming an organic light emitting element on a substrate, and a sealing process of forming a protective layer on the formed organic light emitting layer. The film forming apparatus 300 of the present embodiment mainly performs an organic light emitting element forming process.

The film forming apparatus 300 includes a substrate loading chamber 117, a flipping chamber 111a, a mask loading chamber 90, an alignment chamber 100, a plurality of

film forming chambers

110a and 110b, a transfer chamber 112, a mask separating chamber 113, a flipping chamber 111b, a substrate separating chamber 114, a mask transfer chamber 116, and a carrier transfer chamber 115.

The film forming apparatus 300 further includes a conveying mechanism (described later) for conveying the substrate carrier 9. The substrate carrier 9 is transported along a predetermined transport path passing through each chamber of the film forming apparatus 300. That is, the substrate carrier 9 is transported in the order of the substrate loading chamber 117, the reversing chamber 111a, the mask loading chamber 90, the alignment chamber 100, the plurality of

film forming chambers

110a, 110b, the transport chamber 112, the mask separating chamber 113, the reversing chamber 111b, the substrate separating chamber 114, and the carrier transport chamber 115 as shown by the broken lines, and then returned to the substrate loading chamber 117 again.

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 forming chambers

110a and 110b, the transfer chamber 112, the mask separating chamber 113, and the mask transfer chamber 116, as shown by dotted lines, and then returned to the mask loading chamber 90 again. In this way, the substrate carrier 9 and the mask 6 are each circularly conveyed along a predetermined conveyance path.

The substrate 5 is carried into the substrate carrying-in chamber 117 and mounted on the substrate carrier 9. Specifically, the substrate 5 is carried into the substrate carrying-in chamber 117 with the film formation surface facing upward in the vertical direction. In the substrate loading chamber 117, the substrate carrier 9 is disposed with its holding surface facing upward in the vertical direction. The substrate 5 loaded into the substrate loading chamber 117 is placed on the holding surface of the substrate carrier 9 and held by the substrate carrier 9.

The substrate carrier 9 holding the substrate 5 moves toward the inversion chamber 111 a. Here, the reversing chambers 111a and 111b are provided with reversing

mechanisms

120a and 120b for reversing the orientation of the substrate holding surface of the substrate carrier 9 from the upward side in the vertical direction to the downward side in the vertical direction or from the downward side in the vertical direction to the upward side in the vertical direction. As the turning

mechanisms

120a and 120b, known mechanisms that can change the posture (orientation) by gripping the substrate carrier 9 or the like can be suitably used. The substrate carrier 9 is turned over together with the substrate 5 by the turning mechanism 120a, and the film formation surface of the substrate 5 faces downward in the vertical direction.

On the other hand, after the completion of film formation on the substrate 5 described later, when the substrate carrier 9 is carried in from the mask separating chamber 113 to the reversing chamber 111b, the substrate is carried in with the film formation surface of the substrate 5 facing the lower side in the vertical direction. Therefore, the inverting mechanism 120b inverts the substrate carrier 9 together with the substrate 5 so that the film formation surface of the substrate 5 faces upward in the vertical direction.

The substrate carrier 9 is carried into the mask carrying-in chamber 90 by being turned in the turning chamber 111 a. 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.

An 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 (the substrate 5) on the mask 6. The alignment apparatus 1 then transfers the mask 6 on which the substrate carrier 9 is placed to the transfer roller 15, and starts to transfer toward the next step. As shown in fig. 2 and 3, a plurality of conveying rollers 15 as conveying means are disposed at both sides of the conveying path along the conveying direction, and are rotated by driving forces of an AC servomotor (not shown) to convey the substrate carrier 9 and the mask 6. A speed adjustment chamber for adjusting the speed of the substrate carrier 9 may be provided between the alignment chamber 100 and the film formation chamber 110a and between the film formation chamber 110a and the film formation chamber 110 b. By the speed adjustment, the plurality of substrate carriers 9 are transported at predetermined intervals in the film forming chamber 110.

An evaporation source 7 (film forming means) that emits a vapor deposition material toward the upper side in the vertical direction is disposed in the film forming chamber 110. The substrate 5 held on the substrate carrier and carried into the film formation chamber 110 with the film formation surface facing downward in the vertical direction passes through the evaporation source 7, and is thereby formed on the film formation surface except for the portion blocked by the mask 6. The internal pressure of the chamber of the film forming chamber 110 is adjusted by a vacuum pump and a chamber pressure control unit (not shown) provided with a chamber pressure gauge. The evaporation source 7 includes a material storage portion such as a crucible for storing the vapor deposition material, and a heating mechanism such as a sheath heater for heating the vapor deposition material. The evaporation source 7 may be provided with a mechanism for moving the material storage portion in a plane substantially parallel to the substrate carrier 9 (substrate 5) and the mask 6, and a mechanism for moving the evaporation source as a whole.

After the film formation in the film formation chamber 110 is completed, the substrate carrier 9 and the mask 6 reach the mask separation chamber 113 to be separated from each other in the mask separation chamber 113. The mask 6 separated from the substrate carrier 9 is transferred to the mask transfer chamber 116 and transferred to a new film forming step of the substrate 5. The mask storage device may be disposed in the mask transfer chamber 116 to store a plurality of masks 6 circulating in the film forming device and selectively carry out the masks corresponding to the substrate carrier 9.

On the other hand, the substrate carrier 9 holding the substrate 5 is turned upside down in the turning chamber 111b after being separated from the mask 6, and is conveyed 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 carried out from the film formation apparatus 300. The substrate carrier 9 is transported to the substrate carry-in chamber 117 via the carrier transport chamber 115 for holding a new substrate 5.

The present invention is not limited to the upward deposition structure (structure in which the deposition surface of the substrate 5 faces downward in the vertical direction during deposition) as in the present embodiment. The structure may be a downward deposition structure (a structure in which the film formation surface of the substrate 5 faces upward in the vertical direction during film formation), or a side deposition structure (a structure in which the substrate 5 stands vertically during film formation).

The present invention is applicable not only to a structure in which the substrate carrier 9 is placed on the mask 6, but also to a structure in which the mask 6 is placed on the substrate carrier 9, and any structure in which the substrate carrier 9 and the mask 6 are stacked by positional adjustment can be used. For example, the substrate may be directly carried without providing the substrate carrier and placed on the mask.

The present invention is applicable not only to the above-described tandem type film forming apparatus, but also to a cluster type film forming apparatus in which a plurality of chambers such as a film forming chamber and a mask storage chamber (mask storage chamber) are arranged in a cluster type with a transfer chamber as a center, and a substrate is transferred between the chambers by a robot arm and film is simultaneously formed.

(substrate Carrier)

The structure of the substrate carrier 9 is explained. Fig. 4 (a) is a schematic plan view of the substrate carrier 9. Fig. 4 (b) is a cross-sectional view taken along the direction a in fig. 4 (a), showing a state in which the substrate holding surface is directed upward (in the direction of the front of the paper). The substrate carrier 9 is a flat plate-like structure having a substantially rectangular shape in a plan view.

When the substrate carrier 9 is conveyed, the conveyance rollers 15 support two opposite sides of the four sides of the substrate carrier 9 along the conveyance direction. The conveying roller 15 is constituted by a plurality of conveying rotating bodies disposed on both sides of the conveying path of the substrate carrier 9. The substrate carrier 9 is guided and moved in the transport direction by the rotation of the transport rollers 15.

The substrate carrier 9 has a carrier panel 30, which is a rectangular flat plate-like member, a plurality of chuck members 32, and a plurality of supporting bodies 33. The substrate carrier 9 holds the substrate 5 on the holding surface 31 of the carrier panel 30. In the figure, for ease of understanding, a broken line corresponding to the outer edge of the substrate 5 when the substrate 5 is held is shown. The region inside the broken line is also referred to as a substrate holding portion, and the region outside the broken line is also referred to as an outer peripheral portion. The substrate holding portion and the outer peripheral portion are terms defined for ease of understanding, and there may be no structural difference therebetween.

The chuck member 32 is a protrusion having a chuck surface for chuck the substrate 5. The clip surface is composed of an adhesive member (PSC: physical Sticky Chucking, physical adhesive chuck) and holds the substrate 5 by physical adhesive force and suction force. The plurality of chuck members 32 clamp the substrate 5, respectively, 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 in a state in which the clip faces protrude from the holding face 31 of the carrier panel 30 by a prescribed distance.

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 (frame side portion) of the mask 6 that partitions the film formation region of the substrate 5. This can suppress the influence of the contact of the chuck member 32 with the substrate 5 on the temperature distribution in the film formation region of the substrate 5. In addition, the chuck member 32 is preferably disposed outside the effective display area of the display. This is because there is a concern that the substrate 5 is deformed by the stress generated by the suction of the chuck member 32 or the temperature distribution at the time of film formation is affected.

When the substrate carrier 9 is turned over so that the holding surface 31 of the carrier panel 30 holding the substrate 5 faces downward and placed on the mask 6, the support body 33 supports the substrate carrier 9 on the mask 6. The support body 33 is formed as a convex portion protruding from the holding surface 31 of the carrier panel 30, but may be configured so that the entire substrate 5 is brought into close contact with the mask 6 after being turned over. The support 33 may be configured to support the substrate carrier 9 so as to separate the substrate 5 held by the substrate carrier 9 from the mask 6 at least in the vicinity of the support 33.

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 having a support portion for structurally supporting the substrate 5 from below during inversion may be used. Alternatively, an electrostatic chuck for holding the substrate 5 may be used, which is an electrostatic force generated by applying a voltage to an electrode provided in the carrier panel 30. In addition, a clamping mechanism that clamps the substrate 5 and the mask 6 together may also be used.

(alignment device)

Fig. 2 is a schematic cross-sectional view showing a structure of the film forming apparatus 300 for alignment, which corresponds to the BB view of fig. 1.

The alignment device 1 includes a chamber 4 for maintaining the inside in a vacuum atmosphere or an inert gas atmosphere. The chamber 4 has an upper partition wall 4a, side walls 4b and a bottom wall 4c. A positioning mechanism 60 (alignment mechanism) for driving the substrate carrier 9 to be aligned with respect to the position of the mask 6 is disposed on the upper partition wall 4 a. By disposing the alignment mechanism 60 including a plurality of movable portions outside the chamber, dust generation in the chamber can be suppressed. The alignment apparatus 1 further has a carrier support 8 that holds the substrate carrier 9, a mask receiving table 16 that holds the mask 6, and a conveying roller 15. The alignment chamber 100 itself may be the chamber 4, or the chamber 4 may be disposed inside the alignment chamber 100.

The alignment mechanism 60 changes the relative positional relationship between 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 moving mechanism 11, a Z-lift base 13, and a Z-lift slider 10. The in-plane moving 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 moving mechanism 11, and serves as a base when the substrate carrier 9 moves in the Z direction. The Z lift slider 10 is a member movable in the Z direction along the Z guides 18 (18 a to 18 d). The Z-lift slider is connected to the carrier support 8 via a carrier holding shaft 12.

When the substrate carrier 9 (substrate 5) is moved in the XY θ direction in a plane parallel to the substrate 5, the Z lift base 13, the Z lift slider 10, and the carrier holding shaft 12 are integrally driven to transmit the driving force to the carrier support portion 8. As the in-plane moving mechanism 11 for realizing this, for example, a plurality of driving units that generate driving forces in mutually different directions may be used. The respective driving units generate driving forces corresponding to the movement amounts, so that the position of the Z lift base 13 in the xyθ direction can be controlled.

When the substrate carrier 9 (substrate 5) is Z-moved, the Z-lift slider 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 shafts 12 (12 a to 12 d). In this way, the Z-lift slider or the like functions as a distance changing mechanism, and thereby the relative distance between the substrate carrier 9 and the mask 6 changes.

The alignment mechanism 60 is not limited to the structure that moves the substrate 5 as in the present embodiment, and may be a structure that moves the mask 6 by the alignment mechanism 60, or a structure that moves both the substrate 5 and the mask 6. That is, the alignment mechanism 60 is a mechanism that adjusts the relative position between the substrate 5 and the mask 6 by moving at least one of the substrate 5 and the mask 6.

Fig. 3 is a perspective view showing an embodiment of the alignment device 1. The mask receiving table 16 is lifted up and down along a lift table guide 34 mounted on the mask table base 19. Further, a carrying roller 15 is placed below a side along the carrying direction of the mask 6, and the mask 6 is lowered by a mask receiving table 16 and transferred to the carrying roller 15. A mask used for manufacturing, for example, an organic EL display has the following structure: the mask foil 6b having the openings corresponding to the film formation pattern is fixed in a state of being stretched over the mask frame 6a having high rigidity. With this structure, the mask receiving portion can be held in a state in which the deflection of the mask foil 6b is reduced.

The carrier holding shaft 12 is provided throughout the outside and inside of the chamber 4 through a through hole provided in the upper partition wall 4a of the chamber 4. A carrier support portion 8 is provided below the carrier holding shaft 12, and the substrate 5 can be held via a substrate carrier 9. The section (the portion above the through hole) of the carrier holding shaft 12 from the through hole to the fixing portion to be fixed to the Z-stage slider 10 is covered with a bellows 40 fixed to the Z-stage slider 10 and the upper partition wall 4 a. This can maintain the entire carrier holding shaft 12 in the same vacuum state as the film formation space 2.

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. The ball screw 27 disposed at the center of the Z lift slider transmits the driving force transmitted from the motor 26 fixed to the Z lift base 13 to the Z lift slider 10. The Z-direction position of the Z-elevating slider 10 can be measured from the rotational speed of a rotary encoder, not shown, built in the motor 26. The lifting 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 may be used.

Various operations (alignment by the in-plane moving mechanism 11, lifting of the Z-lift slider 10, substrate holding by the carrier support portion 8, vapor deposition by the evaporation source 7, and the like) performed by the alignment apparatus 1 are controlled by the control portion 70. The control unit 70 is 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 unit 70 are realized by the processor executing a program stored in the memory or the storage. As the computer, a general-purpose personal computer may be used, or an embedded computer or PLC (programmable logic controller ) may be used. Alternatively, part or all of the functions of the control unit 70 may be configured by a circuit such as an ASIC or FPGA.

The control unit 70 may be provided in each chamber of the film forming apparatus 300, or one control unit 70 may control a plurality of chambers or the entire film forming apparatus. The storage unit 71 is a memory in which the control unit 70 stores and reads information. As the storage unit 71, a built-in memory of the control unit 70 can be used.

In order to detect the positions of the substrate 5 and the mask 6 at the time of alignment, image pickup devices 14 (14 a to 14 d) are used. An imaging device 14 for acquiring the positions of the alignment marks on the mask 6 and the alignment marks on the substrate 5 is disposed outside the upper partition wall 4a of the chamber 4. In the upper partition wall 4a, a through hole for imaging is provided on the camera optical axis of the imaging device 14 so that the imaging device 14 can image the inside of the chamber. The window glass 17 (17 a to 17 d) is fitted into the imaging through hole so as to maintain the air pressure inside the chamber.

(Structure of mask)

As shown in fig. 5 (b), the mask 6 has a structure in which a mask foil 6b having a thickness of several μm to several tens μm is welded and fixed to a frame-like mask frame 6 a. The mask frame 6a supports the mask foil 6b in a state of being pulled in the surface direction thereof to prevent the mask foil 6b from flexing. The mask foil 6b includes a boundary portion for dividing a film formation region of the substrate. The boundary portion of the mask foil 6b is in close contact with the substrate 5 when the mask 6 is mounted on the substrate 5, and blocks the film forming material. The mask 6 may be an open mask having only a boundary portion of the mask foil 6b, or may be a fine mask in which a fine opening corresponding to a pixel or sub-pixel is formed in a portion other than the boundary portion, that is, in a portion corresponding to a film formation region of the substrate. When a glass substrate or a substrate having a film made of resin such as polyimide formed on the glass substrate is used as the substrate 5, a ferrous alloy, preferably a ferrous alloy containing nickel, can be used as the main material of the mask frame 6a and the mask foil 6 b.

The mask 6 to be aligned according to the present invention may be a specific mask that is not used for film formation of a product. Such a specific mask is provided with a mask mark at the same position as the normal mask 6 so that the specific mask can be conveyed by the conveying roller 15 and aligned by the alignment device 1 in the same manner as the normal mask 6, and has the same size as the normal mask 6. As an example of the specific mask, a box-shaped mask made of aluminum or the like for confirming the performance of vapor deposition and the vapor deposition state of the film forming apparatus 300 may be used. The specific mask has a shutter that can be opened and closed at a part of the chamber, and the film formation state such as the film thickness can be confirmed by opening and closing the shutter at an arbitrary timing during passage through the film formation chamber 110. Specifically, the substrate mark of the substrate 5 and the mask mark of the specific mask are aligned with each other, and the shutter of the specific mask is passed over the specific film forming source in the film forming chamber 110 in a state where the shutter is opened, whereby the state and performance of the film forming source can be confirmed.

According to the studies of the inventors, the above-mentioned specific mask has problems in material and use method characteristics and processing accuracy, and is likely to be damaged, and therefore damage and discoloration of the mark are often caused. If the mark is damaged or discolored, it is difficult to detect the mark from the captured image, and a mark detection error occurs. Therefore, the inventors studied a mark detection method based on a captured image that does not cause detection errors even when detection is difficult due to a mark becoming blurred by damage or a mark becoming discolored. However, the application object of the present invention is not limited to a specific mask, and can be applied to detection of a mask mark of a normal mask 6 and a substrate mark of a substrate 5. Therefore, in the following description, alignment of the mask mark 38 (mask alignment mark) and the substrate mark 37 (substrate alignment mark) of the substrate 5 using the normal mask 6 will be described.

(alignment)

A method of measuring the positions of the substrate mark 37 and the mask mark 38 using the imaging device 14 will be described with reference to fig. 5 (a) to 5 (c). Fig. 5 (a) is a view of the substrate 5 on the carrier panel 30 in a state of being held by the carrier support portion 8, as viewed from above. For illustration, the carrier panel 30 is illustrated in perspective with dashed lines. Substrate marks 37a to 37d are formed at four corners of the substrate 5. The imaging devices 14a to 14d measure the substrate marks 37a to 37d simultaneously. The control unit 70 calculates the X-direction movement amount, the Y-direction movement amount, and the rotation amount of the substrate 5 from the positional relationship of four points, which are the center positions of the substrate marks 37a to 37d, thereby obtaining positional information of the substrate 5. The substrate mark 37 may be a member containing a metal material provided on the substrate 5, for example.

Fig. 5 (b) is a view of the mask frame 6a from above, and mask marks 38a to 38d are formed at four corners thereof. The imaging devices 14a to 14d measure the mask marks 38a to 38d simultaneously. The control unit 70 calculates the X-direction movement amount, Y-direction movement amount, rotation amount, and the like of the mask 6 from the positional relationship of four points, which are the center positions of the mask marks 38a to 38d, thereby obtaining positional information of the mask 6. The mask mark 38 may be, for example, an opening provided in a member containing a metal material of the mask 6.

Fig. 5 (c) is a diagram schematically showing the field of view 44 of the captured image when one of four groups of mask marks 38 and substrate marks 37 is measured by the imaging device 14. In this example, the substrate mark 37 and the mask mark 38 are measured simultaneously in the field of view 44 of the imaging device 14, so that the positions of the mark centers relative to each other can be measured. The shapes of the mask mark 38 and the substrate mark 37 are not limited to the example of the figure, but a shape having symmetry is preferable in which the center position is easily calculated.

In the case where high-precision alignment is required, a high-magnification CCD camera having a high resolution on the order of several μm is used as the imaging device 14. In such a high-magnification CCD camera, since the field diameter is as small as several mm, if the positional deviation is large when the substrate carrier 9 is placed on the carrier receiving claw, the substrate mark 37 deviates from the field, and cannot be measured. Therefore, as the image pickup device 14, a low-magnification CCD camera having a large field of view is preferably provided in combination with a high-magnification CCD camera. In this case, two-stage alignment may be performed. That is, after performing rough alignment (rough alignment) using a low-magnification CCD camera so that the mask mark 38 and the substrate mark 37 simultaneously fall within the field of view of the high-magnification CCD camera, the high-precision alignment (fine alignment) is performed by performing position measurement of the mask mark 38 and the substrate mark 37 using the high-magnification CCD camera.

The control unit 70 performs marker detection by image processing with respect to a captured image digitized as a pixel value for each pixel. The control unit 70 of the present embodiment can execute two types of image processing methods, i.e., a normalized cross-correlation method and a shape-based matching method (described later), and continue processing based on the detection result. The control unit 70 can acquire relative positional information between the mask frame 6a and the substrate 5 based on positional information of the mask frame 6a and positional information of the substrate 5 acquired by the imaging device 14. The relative position information is fed back to the control unit 70 of the alignment device to control the driving amounts of the driving units such as the Z-lift slider 10, the in-plane movement mechanism 11, the carrier support unit 8, and the like.

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, the substrate carrier 9 is first carried into the chamber 4 and placed on the carrier receiving claws on both sides of the carrier support portion 8.

Next, the alignment device 1 lowers and moves the substrate carrier 9 to an alignment height. The imaging device 14 captures images, and obtains positional information of the substrate mark 37 and the mask mark 38. The control unit 70 performs in-plane movement and imaging of the substrate carrier 9 until the substrate mark 37 and the mask mark 38 approach within a predetermined positional relationship. The control unit 70 determines that the in-plane alignment is completed when the amount of positional displacement between the substrate 5 and the mask 6 is equal to or less than a predetermined threshold value based on the captured image of the alignment mark. Then, the substrate carrier 9 and the mask 6 are relatively moved in a direction perpendicular to the substrate surface, and the substrate carrier 9 is placed on the mask 6, whereby the substrate 5 and the mask 6 are brought into close contact with each other.

(marker detection processing)

The processing in the mark detection of the alignment apparatus 1 is described with reference to the flowchart of fig. 6. In this flow, a process of detecting the substrate mark 37 of the substrate 5 and the mask mark 38 of the mask 6 as a specific mask in the field of view 44 will be described. The specific mask is suitable for the processing of the present process because it is easily damaged or blurred. However, the present invention is not limited to this, and the mask 6 may be a normal mask. The present invention can be used for processing either of the substrate mark 37 and the mask mark 38.

The present flow starts when the image pickup device 14 of the alignment device 1 picks up the mask 6 in the alignment chamber 100 to acquire image data including the substrate mark 37 and the mask mark 38.

In step S101, the control unit 70 analyzes the image data by using template matching (first method) such as Normalized Cross-Correlation (NCC) and the like, and determines the position (coordinates) of the mask mark in the image. The template matching method is not limited to the usual normalized cross-correlation method. For example, a Zero-mean normalized cross-Correlation method (ZNCC: zero-mean Normalized Cross-Correlation) having a high degree of adaptation to a change in brightness may be used. Further, as long as the degree of similarity between a part of the captured image data and the template image can be evaluated, SSD (Sum of Squared Difference, sum of difference), SAD (Sum of Absolute Difference ), or the like may be used. The normalized cross correlation method can accurately identify the consistency of the template and the image, but on the other hand, has low tolerance to noise and distortion, and when damage, blurring, or defects occur in the mark, the similarity is reduced.

Here, (a) of fig. 7 shows a template 381 used for detection of the mask mark 38. The control unit 70 calculates the similarity by moving the template 381 over all positions in the image data as shown in fig. 7 (b) and solving the correlation coefficient with the template at each position. At this time, the image data may be read in gray scale (for example, gray scale represented by gray scale having pixel values of 0 to 255). In the illustrated example, since the position at which the calculated similarity is the maximum is the image position at which the center coordinates of the mask mark 38 are (x 1, y 1), the center coordinates are output as the result. The result output is not limited to the center coordinates. The coordinates of the one or more feature points of the mark, the coordinates of the one or more corners of the mark, and the like may be outputted in a form that can be used in the subsequent alignment process.

Further, the control unit 70 does not immediately output the result even if the image position indicating the maximum similarity is determined. Instead, the control unit 70 compares the detected value of the similarity with a first threshold value (first determination) as shown in step S102. Here, the first threshold value and the second threshold value are both values compared with the similarity in the normalized cross-correlation, and the second threshold value is a value smaller than the first threshold value. The value of the similarity varies depending on the algorithm, and for example, when the maximum value of the similarity is 1.0, the first threshold may be set to 0.9 and the second threshold may be set to 0.8. When the similarity exceeds the first threshold, the control unit 70 determines that the marker detection is successful, proceeds to step S107, and outputs the result by outputting the center coordinates. In outputting the result, information indicating that the similarity exceeds the first threshold may be output. This can notify that the accuracy of the mark detection is relatively high. On the other hand, when the similarity is equal to or smaller than the first threshold, the process advances to step S103.

Here, the case where the similarity is equal to or less than the first threshold value means that the mask mark 38 is in a blurred state due to damage during processing, transportation, or storage, for example, as shown in fig. 7 (c). Since the normalized cross correlation method makes it difficult to detect a mark when there is an influence of blurring or noise, the similarity becomes equal to or smaller than the first threshold in the case of fig. 7 (c). However, if this case is directly regarded as a detection error, although the reliability of the mark detection can be improved, the possibility of detecting the mark is reduced, and the usability of the inspection using a specific mask (or the film formation process using the mask 6) is reduced. Therefore, in this flow, the threshold is changed for the same captured image to perform the determination again, and the possibility of detecting the mark is improved. Among them, the second threshold value is preferably set to a value that does not affect the reliability of the film formation process and inspection.

Specifically, the control unit 70 compares the similarity with a second threshold value smaller than the first threshold value (second determination) in step S103. If the similarity exceeds the second threshold, it is determined that the template matching is successful, and the process proceeds to step S107, and the center coordinates are output as a result. In outputting the result, information indicating that the similarity is equal to or less than the first threshold value and greater than the second threshold value may be output. This can notify that the accuracy is low although the mark is detectable. On the other hand, if the similarity is equal to or less than the second threshold, the detection by the first method is not continued and the process proceeds to step S104. Here, the case where the similarity is equal to or less than the second threshold value means, for example, a state where the mask mark 38 is blurred above the case of fig. 7 (c) as shown in fig. 7 (d), resulting in a lower similarity.

In step S104, the control unit 70 analyzes the image data by using shape-based matching (second method), and determines 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 based on edge information such as edge points, edge intensities, edge gradients, and the like extracted from a model image using a filter or the like, positions that become candidates having the same edges are determined from image data and the similarity with the model image is calculated. In shape-based matching, by extracting information geometrically characterized by edges, resistance to noise and distortion of an image due to damage, blurring, defect, or the like of a mark is enhanced as compared with the normalized cross-correlation method. In addition, the light-emitting diode has resistance to brightness, contrast and shade changes. In addition, in the shape-based matching, since geometric information such as a contour is used, the color of the mark is irrelevant. This can improve the detection possibility even when the surface is discolored or the color is reversed.

In the second method, the control unit 70 also compares the similarity with a threshold value in step S105. The threshold (third threshold) is a value related to the similarity in the shape-based matching, unlike the first threshold and the second threshold, and the specific set value is a value corresponding to the algorithm. If the similarity exceeds the third threshold, it is determined that the matching based on the shape is successful, and the process proceeds to step S107, and the center coordinates are output as a result. In outputting the result, information indicating that coordinates are acquired by shape-based matching may be output. This allows the detection of the marker but with a relatively low accuracy to be communicated to subsequent processing.

On the other hand, when the similarity is equal to or smaller than the third threshold, the control unit 70 does not continue the detection by the second method, and proceeds to step S106, and notifies the subsequent processing of the occurrence of the flag detection error. The control unit 70 presents information or sounds on the display when a detection error occurs, so as to prompt the user to confirm the state of the mask 6.

In this process, it is assumed that the mask mark 38 exists in the field of view 44. However, there is also a possibility that the result of S105 becomes "no" because the mask mark 38 is not present within the field of view 44. Therefore, the control unit 70 may perform the alignment again instead of notifying the user in the subsequent processing of receiving the notification of S106.

Although the above description is omitted, in this flow, the substrate mark 37 is detected. If the result of any of steps S102, S103, and S107 is yes, the coordinates of the mask mark 38 and the substrate mark 37 are outputted to the subsequent process. Thus, the control unit 70 can determine whether or not the positional relationship between the mask mark 38 and the substrate mark 37 is within a predetermined range, and thereby determine whether or not the alignment is good.

In steps S101 and S104 of the present routine, the control unit 70 attempts to detect the alignment mark. At this time, the control unit 70 functions as a detection means for the mark. In steps S102, S103, and S105, the control unit 70 determines whether the detection result of the alignment mark is good, outputs the result when the detection result is good, and changes the threshold value or the conversion method when the detection result is bad. At this time, the control unit 70 functions as a determination means for determining whether the mark is detected or not.

As described above, according to the present embodiment, detection of a mark is performed from a captured image using a plurality of detection methods. Thus, the features of the respective detection methods can be combined to improve the detection probability of the label. For example, when detecting a mark from a captured image, even if detection cannot be performed by the first method, by using the second method of edge extraction which is highly resistant to noise, the detection probability of the mark is improved.

In the present procedure, after the normalized cross-correlation method is used as the first method, shape-based matching is used as the second method. This is because, in general, the reproducibility of the detection position by the normalized cross-correlation method is high, and the alignment accuracy can be improved. Thus, in this flow, a normalized cross-correlation method is performed using a plurality of thresholds. On the other hand, since the normalized cross correlation method has a surface with poor tolerance to image overlapping, cracking, chipping, and noise, there is a high possibility that detection errors occur in a mask (for example, a specific mask made of aluminum) that is susceptible to damage. Therefore, in the present flow, by performing the shape-based matching method as the second method, the detection probability can be further improved. However, the context of the first method and the second method is not limited thereto.

In the above-described flow, by using two thresholds in the first method, the marker detection probability from the same captured image is thereby improved. However, the effects of the present invention can be exerted by combining at least the first method and the second method. In the first method, the number of stages of the determination may be increased by using three or more thresholds. Further, in the second method, the determination may be performed stepwise using a plurality of thresholds.

Method for manufacturing electronic device

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, a structure of an organic EL display device is shown, and a method of manufacturing the organic EL display device is exemplified.

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

As shown in fig. 8 (a), a plurality of pixels 702 each including a plurality of light-emitting elements are arranged in a matrix in a display region 701 of the organic EL display device 700. The light emitting elements each have a structure including an organic layer sandwiched between a pair of electrodes, and details thereof will be described later. Here, the pixel means a minimum unit in which a desired color can be displayed in the display region 701. In the case of the organic EL display device of the present embodiment, the pixel 702 is configured by a combination of the first light emitting element 702R, the second light emitting element 702G, and the third light emitting element 702B which exhibit mutually different light emission. The pixel 702 is often constituted by a combination of a red light emitting element, a green light emitting element, and a blue light emitting element, but may be a combination of a yellow light emitting element, a cyan light emitting element, and a white light emitting element, and is not particularly limited as long as it is at least 1 color or more.

Fig. 8 (B) is a partially cross-sectional schematic view at line B-B of fig. 8 (a). The pixel 702 is formed of a plurality of light-emitting elements, each of which has a first electrode (anode) 704, a hole-transporting layer 705, any one of light-emitting

layers

706R, 706G, and 706B, an electron-transporting layer 707, and a second electrode (cathode) 708 over a substrate 703. Among them, the hole transport layer 705, the

light emitting layers

706R, 706G, and 706B, and the electron transport layer 707 correspond to organic layers. In this embodiment, the light-emitting layer 706R is an organic EL layer that emits red light, the light-emitting layer 706G is an organic EL layer that emits green light, and the light-emitting layer 706B is an organic EL layer that emits blue light. The light-emitting

layers

706R, 706G, and 706B are each formed in a pattern corresponding to a light-emitting element (sometimes referred to as an organic EL element) that emits red light, green light, and blue light.

The first electrode 704 is formed separately for each light-emitting element. The hole-transporting layer 705, the electron-transporting layer 707, and the second electrode 708 may be formed in common among the plurality of light-emitting

elements

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

In fig. 8 (b), the hole transport layer 705 and the electron transport layer 707 are shown as one layer, but may be formed of a plurality of layers including a hole blocking layer and an electron blocking layer according to the structure of the organic EL display element. In addition, a hole injection layer having an energy band structure that enables smooth injection of holes from the first electrode 704 into the hole transport layer 705 may be formed between the first electrode 704 and the hole transport layer 705. Also, an electron injection layer may be formed between the second electrode 708 and the electron transport layer 707.

Next, an example of a method of manufacturing the organic EL display device will be specifically described.

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

An acrylic resin is formed over the substrate 703 over which the first electrode 704 is formed by spin coating, and the insulating layer 709 is formed by patterning the acrylic resin by photolithography so that an opening is formed in a portion where the first electrode 704 is formed. The opening corresponds to a light-emitting region where the light-emitting element actually emits light.

The substrate 703 patterned with the insulating layer 709 is mounted on a substrate carrier provided with an adhesive member. The substrate 703 is held by an adhesive member. The organic material is carried into the first organic material film forming apparatus, and after the inversion, the hole transport layer 705 is formed as a common layer on the first electrode 704 in the display region. The hole transport layer 705 is formed by vacuum evaporation. In practice, since the hole transport layer 705 is formed to be larger in size than the display region 701, a high-definition mask is not required.

Next, the substrate 703 formed on the hole transport layer 705 is carried into a second organic material film forming apparatus. Alignment of the substrate and the mask is performed, and the substrate is placed on the mask, whereby a red light-emitting layer 706R is formed at a portion of the substrate 703 where the red light-emitting element is arranged.

In the same manner as the formation of the light-emitting layer 706R, a light-emitting layer 706G that emits green light is formed by a third organic material film forming device, and a light-emitting layer 706B that emits blue light is formed by a fourth organic material film forming device. After the formation of the light-emitting

layers

706R, 706G, and 706B is completed, an electron transport layer 707 is formed over the entire display region 701 by a fifth film formation device. The electron transport layer 707 is formed as a common layer on the

light emitting layers

706R, 706G, 706B of three colors.

The substrate formed to the electron transport layer 707 is moved in a metallic vapor deposition material film forming apparatus to form a second electrode 708.

Thereafter, the film is transferred to a plasma CVD apparatus to form the protective layer 710, thereby completing the film forming process on the substrate 703. After the inversion, the adhesive member is peeled off from the substrate 703 to separate the substrate 703 from the substrate carrier. After that, the organic EL display device 700 is completed by cutting.

When the substrate 703 on which the insulating layer 709 is patterned is carried into the film forming apparatus until the formation of the protective layer 710 is completed, if the substrate is exposed to an atmosphere containing moisture or oxygen, the light-emitting layer made of the organic EL material may be degraded by the moisture or oxygen. Therefore, in this example, the substrate is carried in and out between the film forming apparatuses under a vacuum atmosphere or an inert gas atmosphere.

Claims

1. An alignment device, comprising:

an alignment mechanism for aligning a substrate to be film-formed with a mask;

2. The alignment device of claim 1,

the first method is template matching and the second method is shape-based matching.

3. The alignment device of claim 1,

the first method is a normalized cross-correlation method.

4. An alignment device as claimed in claim 3, wherein,

the detection means outputs a similarity between the alignment mark and a template when detecting the alignment mark using the normalized cross-correlation method,

the determination means determines that the detection of the alignment mark by the first method is not good when the similarity is equal to or smaller than a predetermined threshold.

5. An alignment device as claimed in claim 3, wherein,

the determination by the determination means includes a first determination that is determined to be a poor detection of the alignment mark when the degree of similarity is a first threshold or less, and a second determination that is determined to be a poor detection of the alignment mark when the degree of similarity is a second threshold or less that is smaller than the first threshold.

6. The alignment device of claim 5,

the determination means performs the second determination when it is determined that the detection of the alignment mark is not good in the first determination.

7. The alignment device of claim 6,

the determination means outputs information indicating which of the first determination and the second determination the alignment mark is detected when the alignment mark is detected by the first method.

8. An alignment device as defined in claim 2, wherein,

the detection means is configured to detect the alignment mark even when the color of the alignment mark is reversed in detection of the alignment mark using the shape-based matching.

9. The alignment device of any of claims 1-8,

the alignment mark of the substrate is a member containing a metal material provided on the substrate, and the alignment mark of the mask is an opening provided on the member containing a metal material.

10. The alignment device of any of claims 1-8,

The alignment mechanism adjusts a relative position of the substrate and the mask based on information related to the alignment mark of the substrate and the alignment mark of the mask determined to be good by the determination mechanism.

11. A film forming apparatus is characterized by comprising:

the alignment device of any of claims 1-10; and

and a film forming mechanism for forming a film on the substrate aligned by the alignment device through the mask.