JP2012104393A - Alignment method, alignment device, and manufacturing method and manufacturing apparatus of organic el display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alignment method and an alignment device of reducing damage to a substrate and a mask by reducing alignment operation times of the substrate and the mask.SOLUTION: The method includes: holding a substrate 11 on substrate holding means 13; then, detecting an amplitude of vibration of the substrate 11 in the gravity direction; predicting a statically determinate position of the substrate 11 based on information of the amplitude; and aligning the substrate 11 and a mask 12 based on a position of an alignment mark at the statically determinate position.

Description

  The present invention relates to an alignment method and an alignment apparatus for aligning a substrate and a mask when vapor deposition material is vapor-deposited on the substrate through a mask, and more particularly to a method and an apparatus for manufacturing an organic EL (electroluminescence) display device. Is.

  An organic EL element using organic EL has been attracting attention as a light emitting element capable of high luminance emission by low voltage driving. In manufacturing a display device using such a light emitting element, R (red), G (green), and B (blue) light emitting organic materials are selectively formed as fine patterns on the electrodes in order to achieve full color. As a forming method, a mask vapor deposition method as described in Patent Document 1 is known. In the mask vapor deposition method, it is necessary to perform an alignment operation between the substrate and the mask and deposit an organic EL material at a predetermined position.

  In general, in the alignment operation between the substrate and the mask, an alignment mark provided on each of the substrate and the mask is imaged by a camera, the position is recognized by image processing, and the position of the mark is mechanically aligned. Usually, the alignment operation is performed after the substrate is carried into the vapor deposition apparatus, and the error of the relative position between the alignment marks is confirmed when the substrate is separated from the mask immediately after the substrate is carried and when the substrate is brought into contact with the mask. Done. In the error check between the alignment marks performed after the substrate and the mask are brought into contact with each other, if they are not within the target error range, the substrate is once separated from the mask and the alignment operation is performed again.

JP 2009-64758 A

  However, as described above, the alignment operation of the substrate and the mask is often performed immediately after the substrate is loaded, and the alignment mark on the substrate and the mask is used with the camera while the substrate is vibrating in the direction of gravity. The position is recognized. If the substrate vibrates in the direction of gravity, the size of the alignment mark changes, which affects the recognition rate and position accuracy of the alignment mark when image processing is performed. And due to the decrease in the alignment mark recognition rate, it may not be within the target error range, and the contact between the substrate and the mask may be repeated, the substrate and the mask are damaged, the tact time is not constant, and the productivity is increased. Improvement is also difficult.

  An object of the present invention is to provide an alignment method and an alignment apparatus in which damage to the substrate and the mask is reduced by reducing the number of times of the alignment operation between the substrate and the mask. Furthermore, another object of the present invention is to provide a method and apparatus for manufacturing an organic EL display device with improved productivity using the alignment method and alignment apparatus.

The first of the present invention is an alignment method between a substrate and a mask,
Fixing the mask to the mask holding means;
Holding the substrate on the substrate holding means;
A vibration detection step of detecting vibration in the gravitational direction of the substrate in a state where the substrate and the mask are arranged to face each other at a predetermined distance;
Based on the vibration information detected in the vibration detection step, a position information detection step of predicting a position where the substrate is stabilized and detecting alignment mark position information from image information at the predicted stabilization position;
Based on the alignment mark position information detected in the position information detection step, a calculation step for calculating a horizontal shift amount in the horizontal direction between the substrate and the mask;
A moving step of moving at least one of the substrate and the mask in the horizontal direction based on the amount of deviation calculated in the calculating step;
It is characterized by having.

A second aspect of the present invention is an alignment apparatus that performs alignment between a substrate and a mask,
Vibration detecting means for detecting the amplitude of vibration in the gravitational direction of the substrate;
The relative positions of the alignment marks provided on the substrate and the mask are imaged from the gravitational direction of the substrate, and at least one of the substrate and the mask is moved in the horizontal direction so that the alignment mark is at a predetermined relative position. Alignment means
It is characterized by having.

  3rd of this invention is a manufacturing method of the organic electroluminescence display which has a vapor deposition process which vapor-deposits an organic material on the film-forming surface of a board | substrate through a mask, Comprising: Alignment with the said board | substrate and mask in the said vapor deposition process This is performed by the alignment method of the present invention.

  According to a fourth aspect of the present invention, there is provided an apparatus for manufacturing an organic EL display device, wherein an organic material emitted from a vapor deposition source in a vacuum vapor deposition chamber is vapor deposited on a film formation surface of a substrate through a mask. The alignment apparatus according to 2 is provided.

  According to the present invention, in alignment between a mask and a substrate, alignment marks can be accurately aligned even if the substrate vibrates in the direction of gravity, and tact improvement is achieved by improving alignment accuracy and reducing retry of the alignment operation. Is possible. Therefore, it is possible to manufacture the organic EL display device with high productivity.

It is a schematic diagram which shows the structure of one Embodiment of the manufacturing apparatus of the organic EL display device of this invention of this invention. It is a conceptual diagram which shows the vibration of the gravity direction of a board | substrate based on this invention. It is a plane schematic diagram of a mask and a substrate according to the present invention.

  The alignment method and alignment apparatus of the present invention relate to alignment (positioning) between a substrate and a mask when an organic material is vapor-deposited on the substrate through a mask in an organic EL display device. In the alignment method of the present invention, when the substrate and the mask are aligned, vibration in the gravitational direction of the substrate is detected, and alignment mark position information at the stationary position of the substrate predicted based on the obtained vibration information is detected for alignment. It is characterized by performing. Thereby, alignment can be performed accurately and efficiently without waiting for the vibration of the substrate to converge. Therefore, the substrate and the mask can be accurately aligned in a non-contact state, and the number of times that the substrate and the mask are separated again after contact is reduced. That is, by repeating the contact and non-contact between the substrate and the mask to the minimum necessary, damage due to the contact between the substrate and the mask can be reduced and alignment can be performed in a short time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, well-known or publicly-known techniques in the technical field are applied to portions that are not particularly illustrated or described. The embodiment described below is one embodiment of the present invention and is not limited thereto.

  FIG. 1 is a schematic diagram showing a configuration of an embodiment of a manufacturing apparatus of an organic EL display device provided with the alignment apparatus of the present invention. In FIG. 1, a substrate 11 and a mask 12 are disposed in a vacuum chamber 10. The substrate 11 is usually a glass substrate in the organic EL display device. In the vacuum chamber 10 of FIG. 1, the mask 12 is fixed to a mask holding unit (not shown), and the substrate 11 is transferred into the vacuum chamber 10 by a substrate transfer mechanism (not shown) and held by the substrate holding unit 13. Yes. In the vacuum chamber 10, an evaporation source 16 for forming a film on the substrate 11 is provided.

  FIG. 3A shows a schematic plan view of the mask 12, and FIG. 3B shows a schematic plan view of the substrate 11. As shown in FIG. 3A, the mask 12 has a plurality of openings 30 corresponding to the pixel pattern, and an alignment mark 31 is formed at a predetermined position. Further, as shown in FIG. 3B, the display unit 32 is disposed on the substrate 11, and an alignment mark 33 is formed at a predetermined position on the end. The alignment mark 33 on the glass substrate is formed of a reflective material such as Cr. The alignment mark 31 of the mask 12 is generally a through hole. The alignment mark 33 on the substrate 11 and the alignment mark 31 on the mask 12 are formed at positions corresponding to each other. That is, the state in which the alignment mark 33 of the substrate 11 positioned below the mask 12 is observed at the center of the alignment mark 31 of the mask 12 when viewed from the mask 12 side is a desired relative position between the substrate 11 and the mask 12. It is.

  A window 14 is formed above the vacuum chamber 10 in FIG. 1 at a position corresponding to the alignment mark 33 of the substrate 11 and the alignment mark 31 of the mask 12. An imaging device 15 is arranged vertically upward via the window 14. The imaging device 15 includes a CCD camera, a lens, and the like, and captures reflected or transmitted images of the alignment marks 31 and 33 on the substrate 11 and the mask 12. The illuminating device 17 includes, for example, a halogen light source and a lens, and irradiates the substrate 11 and the mask 12 with irradiation light in the same direction as the optical axis of the CCD camera via the half mirror 19 or the like. Irradiation light may be irradiated from above the substrate 11 and the mask 12, or may be irradiated from below. When irradiated from below, the imaging device 15 captures transmission images of the alignment marks 31 and 33 of the substrate 11 and the mask 12. The light receiving element 18 receives reflected light from the substrate 11. In this example, illumination light for imaging with the imaging device 15 is used as a light source, but an illumination device may be provided separately. The illumination device 17, the imaging device 15, and the light receiving element 18 are not limited to two, and may be one or three or more.

  An alignment method between the substrate 11 and the mask 12 in the method for manufacturing an organic EL display device of the present invention will be described with reference to the apparatus shown in FIG. First, the mask 12 is fixed to a mask holding means (not shown) in the vacuum chamber 10, and then the substrate 11 is held on the substrate holding means 13 above the mask by a substrate transport mechanism (not shown). At this point, the film formation surface of the substrate 11 and the mask 12 are arranged to face each other with a predetermined distance. Then, illumination light is emitted from the irradiation device 17, reflected by the substrate 11 and the mask 12, and received by the imaging device 15. The light reception information obtained by the imaging device 15 is sent to the vibration detection means 20 as image information. Then, based on the image information, the vibration detection unit 20 calculates the amplitude of vibration of the substrate 11 based on the horizontal position detection error of the alignment mark 31 of the substrate 11 caused by the vibration of the substrate 11 in the gravity direction.

  FIG. 2 is a conceptual diagram showing the vibration in the gravity direction of the substrate 11 detected by the vibration detecting means 20. The vertical axis is the displacement of the substrate 11 and the horizontal axis is the time, and it can be seen that the vibration gradually converges after the substrate 11 is held. In the time until the vibration state is converged and the substrate 11 is settled, the stationary position (A) of the substrate 11 is predicted from the amplitude of the vibration of the substrate 11, and a predetermined value represented by T1 to T5. Image information captured within the time interval is used for alignment mark position information detection. Since the stationary position of the substrate 11 is near the amplitude center of the substrate 11, the displacement of the substrate 11 to be used for imaging and its time interval are determined from the error accuracy (z) of the alignment mark position allowed.

  In addition, an offset may be used with respect to the stationary position in consideration of bending and warping of the substrate 11 used in advance. Further, the substrate 11 to be used may be subjected to feedback by learning the vibration amplitude of the substrate and the position after stabilization from the position information of the substrate 11 after the alignment is completed. Further, the optical path used for detection in the vibration detection of the substrate 11 may not be coaxial with the imaging device 15, and the illumination for detecting the light amount fluctuation may use light from the illumination device 17 for imaging with the CCD, Another illumination mechanism may be provided. For example, it is desirable to reduce the depth of focus using a short wavelength laser or a high NA lens in order to detect the displacement of the substrate vibration with high accuracy.

  In the present invention, an existing technique can be used as means for detecting the vibration of the substrate 11. For example, the light reflected from the substrate 11 may be calculated from the balance of the light amounts by the divided light receiving elements. In addition, the image information captured by the CCD camera in a state where the predicted position of the substrate is in focus may be calculated from the contrast ratio of the image, but is not limited thereto.

  After the vibration of the substrate 11 is converged, the alignment marks provided on the substrate 11 and the mask 12 are aligned. First, the image information obtained by the imaging device 15 is subjected to image recognition processing such as pattern matching by an image processing control device (not shown), and the relative position between the alignment mark on the substrate 11 and the alignment mark on the mask 12 is determined. Detected. Then, the amount of displacement in the horizontal direction between the substrate 11 and the mask 12 is calculated, and at least one of the substrate 11 and the mask 12 is moved in the horizontal direction so that the alignment mark is at a predetermined relative position based on the calculated amount of displacement. . Imaging is performed again after the substrate 11 or the mask 12 is moved. If the alignment mark is not at a predetermined relative position, imaging and alignment are performed again. If the alignment mark is at the predetermined position, alignment of the alignment mark is completed. Thereafter, the substrate 11 and the mask 12 are brought into close contact with each other, and the alignment mark is imaged again. If the alignment mark is not at a predetermined position, the substrate 11 and the mask 12 are separated again, and the alignment is performed again. If it is confirmed that the substrate 11 and the mask 12 are in close contact with each other and the alignment mark is in a predetermined position, the alignment is completed. When the alignment is completed, vapor deposition according to the mask pattern is performed by the vapor deposition source 16.

  By aligning the alignment marks of the substrate 11 and the mask 12 as described above, the substrate 11 and the mask 12 can be aligned with high accuracy and high speed without waiting for the vibration of the substrate 11 to converge. It becomes.

(Example)
In the organic EL display device manufacturing apparatus having the configuration illustrated in FIG. 1, the substrate 11 and the mask 12 are aligned. A glass substrate of 460 mm × 365 mm × 0.5 mm was used as the substrate 11, the distance from the mask 12 was 4.5 mm, and the distance from the substrate 11 to the image sensor 15 was 200 mm. The alignment mark of the substrate 11 is a chromium film having a diameter of 0.3 mm, and the alignment mark of the mask 12 is a through hole having a diameter of 0.5 mm.

  The value of the amplitude in which the vibration in the gravity direction of the substrate 11 is allowed during alignment was 200 μm, and the alignment of the substrate 11 and the mask 12 was performed 10 times. As a result, the average alignment accuracy was ± 3.9 μm, and the required time from completion of substrate loading to completion of alignment was 13 seconds on average. In the 2-minute tact assumption, the average tact was a result satisfying the tact in 1 minute 55 seconds.

(Comparative example)
The alignment of the substrate 11 and the mask 12 was performed 10 times in the same manner as in the example except that the vibration in the gravity direction of the substrate 11 was not detected. As a result, the alignment accuracy was 4.8 μm on average, and the time required from completion of substrate loading to completion of alignment was 25 seconds on average. In the 2-minute tact assumption, the average tact could not satisfy the tact at 2 minutes 15 seconds. The reason why the time required for completion of alignment in this example is longer than that in the example is that the alignment between the substrate 11 and the mask 12 was performed without predicting the stationary position of the substrate, and the number of re-alignments increased. is there.

  11: substrate, 12: mask, 13: substrate holding means, 20: vibration detecting means, 31, 33: alignment mark

Claims (4)

An alignment method between a substrate and a mask,
Fixing the mask to the mask holding means;
Holding the substrate on the substrate holding means;
A vibration detection step of detecting vibration in the gravitational direction of the substrate in a state where the substrate and the mask are arranged to face each other at a predetermined distance;
Based on the vibration information detected in the vibration detection step, a position information detection step of predicting a position where the substrate is stabilized and detecting alignment mark position information from image information at the predicted stabilization position;
Based on the alignment mark position information detected in the position information detection step, a calculation step for calculating a horizontal shift amount in the horizontal direction between the substrate and the mask;
A moving step of moving at least one of the substrate and the mask in the horizontal direction based on the amount of deviation calculated in the calculating step;
An alignment method comprising: An alignment apparatus for aligning a substrate and a mask,
Vibration detecting means for detecting the amplitude of vibration in the gravitational direction of the substrate;
The relative positions of the alignment marks provided on the substrate and the mask are imaged from the gravitational direction of the substrate, and at least one of the substrate and the mask is moved in the horizontal direction so that the alignment mark is at a predetermined relative position. Alignment means
An alignment apparatus comprising:   The manufacturing method of the organic electroluminescence display which has the vapor deposition process which vapor-deposits an organic material through the mask on the film-forming surface of a board | substrate, Comprising: Alignment of the said board | substrate and mask in the said vapor deposition process is described in Claim 1. An organic EL display device manufacturing method, which is performed by an alignment method.   An apparatus for manufacturing an organic EL display device that performs a vapor deposition process in which an organic material emitted from a vapor deposition source in a vacuum vapor deposition chamber is vapor-deposited on a film formation surface of a substrate via a mask. An apparatus for manufacturing an organic EL display device, comprising:

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