JP2008293841A - Mask alignment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a relative position between a glass substrate and a mask at high precision in a mask alignment device for aligning positions between the glass substrate and metal mask in order to manufacture an organic EL display. <P>SOLUTION: Two sets of lighting devices as a coaxial vertical lighting device 22 and slant lighting device 23 are arranged. The slant lighting device 23 can turn on and off by using a shutter 32. A pattern of an alignment mark 16 at a substrate side is photographed at timing wherein the slant lighting is turned off, and a pattern of an alignment mark 17 at a mask side is photographed at timing wherein the slant lighting is turned on. Thus, an image with greater contrast can be photographed, and the relative position between the glass substrate 11 and metal mask 12 can be detected at high precision. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mask alignment apparatus for aligning a glass substrate and a metal mask in order to manufacture an organic EL (Electro Luminescence) display.

  In the organic EL display manufacturing apparatus, as shown in Patent Documents 1 to 3, it is necessary to precisely align the glass substrate and the metal mask and form the organic EL material in a desired pattern by vacuum deposition. . For this reason, alignment marks are formed on the glass substrate and the metal mask, and the alignment mark positions provided on the glass substrate and the metal mask are imaged by a CCD (Charge Coupled Device) camera. The alignment mark of the glass substrate is formed by a metal thin film such as chromium, and the alignment mark of the metal mask is generally formed by a through hole.

  The optical system for photographing this alignment mark is a coaxial epi-illumination in which the optical axis of the CCD camera and the illumination direction of the illumination light are arranged coaxially because the alignment mark on the glass substrate is a mirror-like reflector with a smooth surface. A method is used.

  There are various variations of the surface roughness of the metal mask depending on the material and manufacturing method. In particular, in the case of a metal mask with a large surface roughness, when shooting with coaxial epi-illumination, the illumination light is scattered by unevenness on the mask surface, so the contrast between the metal mask surface and the through hole (mask side alignment mark) It becomes small and it becomes difficult to recognize the position with high accuracy.

On the other hand, in order to improve the contrast between the metal mask and the through-hole, in addition to the coaxial epi-illumination, a ring-shaped illumination for irradiating from the oblique direction with respect to the optical axis of the CCD camera may be used as an auxiliary. .
JP 2006-12597 A JP 2004-264404 A JP 2004-303559 A

  However, this method improves the contrast of light and dark, but the average brightness on the surface of the metal mask approaches the brightness of the alignment mark on the glass substrate, and the unevenness of the brightness caused by the unevenness on the surface of the metal mask overlaps. The problem arises that it becomes difficult to recognize.

  In view of the above-described problems, an object of the present invention is to provide a mask alignment apparatus that can detect a relative position between a glass substrate and a metal mask with high accuracy.

  In order to solve the above-described problems, the present invention images a substrate-side alignment mark formed on a glass substrate and a mask-side alignment mark formed on a mask, and images the substrate-side alignment mark and the mask-side alignment mark. In a mask alignment apparatus that calculates a relative positional relationship between the glass substrate and the mask from an image and aligns the glass substrate and the mask based on the calculated relative positional relationship, the substrate-side alignment mark and the mask side Imaging means for imaging the alignment mark, coaxial epi-illumination means for irradiating illumination light coaxially with the optical axis of the imaging means, and oblique illumination for illuminating illumination light from an oblique direction with respect to the optical axis of the imaging means Means, oblique illumination control means for controlling turning on / off of the oblique illumination means, and imaging by the imaging means. The position of the mask-side alignment mark and the position of the substrate-side alignment mark are detected using the obtained image, and based on the detection position of the substrate-side alignment mark and the detection position of the mask-side alignment mark, the glass Control means for calculating a shift amount between the substrate and the mask, and substrate moving means for aligning the glass substrate and the mask based on the calculated shift amount.

  According to this invention, alignment of the glass substrate and the metal mask is performed by using two illuminations of coaxial incident illumination and oblique illumination. When such two illuminations are used, the reflected light from the substrate side alignment mark and the mask side alignment mark can be captured in a larger contrast image, and the substrate side alignment mark and the mask side alignment mark can be captured. The relative position can be detected with high accuracy.

  In the above invention, the control means includes: first mark detection means for detecting a position of the substrate-side alignment mark from an image taken by the imaging means in a state where the oblique illumination is turned off; Second mark detection means for detecting the position of the mask side alignment mark from an image picked up by the image pickup means in a state where illumination is turned on, and the position of the substrate side alignment mark detected by the first mark detection means And based on the detection position of the mask side alignment mark detected by the second mark detection means, to calculate the amount of deviation between the glass substrate and the mask, based on the calculated amount of deviation, And a first alignment processing means for aligning the glass substrate and the mask.

  According to this invention, the substrate-side alignment mark pattern and the mask are captured by capturing the pattern of the substrate-side alignment mark at the timing when the oblique illumination is turned off and capturing the pattern of the mask-side alignment mark at the timing when the oblique illumination is turned on. The reflected light from the side alignment mark can be captured with a larger contrast image, and the relative position between the glass substrate and the metal mask can be detected with higher accuracy.

  In the above invention, the control means detects the position of both the substrate side alignment mark and the mask side alignment mark from the image picked up by the image pickup means with the oblique illumination turned on. And calculating the amount of deviation between the glass substrate and the mask based on the detection position of the substrate side alignment mark and the mask side alignment mark detected by the third mark detection means, Based on the second alignment processing means for aligning the glass substrate and the mask, and after the alignment by the first alignment processing means, the second alignment processing means It is characterized by the fact that the position alignment is performed.

  According to this invention, in the first position detection, the oblique illumination is switched on and off, and the substrate side alignment mark and the mask side alignment mark are separately detected. By detecting the substrate side alignment mark and the mask side alignment mark process at the same time while the illumination is turned on, the processing speed can be increased.

  According to the present invention, the substrate-side alignment mark pattern and the mask are captured by capturing the pattern of the substrate-side alignment mark at the timing when the oblique illumination is turned off and capturing the pattern of the mask-side alignment mark at the timing when the oblique illumination is turned on. The reflected light from the side alignment mark can be captured with a larger contrast image, and the relative position between the glass substrate and the metal mask can be detected with high accuracy. Even with an inexpensive metal mask having a large surface roughness, the positions of the glass substrate and the metal mask can be correctly aligned.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
FIG. 1 shows the configuration of a vapor deposition apparatus for an organic EL display incorporating the mask alignment apparatus of the present invention. In FIG. 1, a glass substrate 11 and a metal mask 12 are stacked in a vacuum container 10. The metal mask 12 has a plurality of openings 13 corresponding to the pixel pattern of the display. The metal mask 12 is fixed in the vacuum container 10 by a holding mechanism (not shown). On the other hand, the glass substrate 11 is movable with respect to the metal mask 12 by the substrate moving mechanism 42. A vapor deposition source 15 for forming an organic EL material on the glass substrate 11 is provided in the vacuum container 10.

  A substrate-side alignment mark 16 is formed at a predetermined position on the glass substrate 11. The substrate-side alignment mark 16 is a substantially specular reflective material made of a metal thin film such as chromium. A mask side alignment mark 17 is formed at a predetermined position of the metal mask 12. The mask side alignment mark 17 is a through hole. The substrate side alignment mark 16 and the mask side alignment mark 17 are formed at positions corresponding to each other.

  A window 18 is formed on the upper surface of the vacuum vessel 10. The window 18 is formed at a position where the substrate side alignment mark 16 and the mask side alignment mark 17 can be irradiated with irradiation light when the glass substrate 11 and the metal mask 12 are arranged in the vacuum vessel 10.

  An optical device 20 is disposed on the upper side outside the vacuum vessel 10 at a position corresponding to the window 18. The optical device 20 includes an imaging device 21, a coaxial incident illumination device 22, and an oblique illumination device 23.

  The coaxial epi-illumination device 22 irradiates irradiation light in a direction coaxial with the optical axis of the imaging device 21. The oblique illumination device 23 irradiates irradiation light from an oblique direction with respect to the optical axis of the imaging device 21. The imaging device 21 images reflected light from the substrate side alignment mark 16 and the mask side alignment mark 17.

  FIG. 2 illustrates the configuration of the optical device 20 according to the first embodiment of the present invention. In FIG. 2, the imaging device 21 includes a CCD camera 24 and a lens 25. The imaging device 21 photographs the glass substrate 11 and the metal mask 12 from substantially vertically above. A coaxial incident illumination device 22 and an oblique illumination device 23 are attached to the lens 25.

  The coaxial epi-illumination device 22 includes a halogen light source 26 and a light guide 27. Illumination light emitted from the halogen light source 26 through the light guide 27 is bent by a half mirror 28 in the lens 25 and coaxial with the lens optical axis. The glass substrate 11 and the metal mask 12 are irradiated.

  On the other hand, the oblique illumination device 23 includes a halogen light source 29, a light guide 30, and a ring illumination head 31, and irradiates illumination light obliquely with respect to the lens optical axis. In addition, the oblique illumination device 23 is provided with a shutter 32. By opening and closing the shutter 32, the oblique illumination can be switched on and off at high speed. The opening / closing of the shutter 32 is switched by a control signal from the image processing control device 40 (shown in FIG. 1).

  Further, as shown in FIG. 1, when aligning the glass substrate 11 and the metal mask 12, coaxial epi-illumination and oblique illumination are emitted from the coaxial epi-illumination device 22 and the oblique illumination device 23 of the optical device 20. The The reason why the two types of illumination, coaxial epi-illumination and oblique illumination, are used as illumination and the opening / closing timing thereof will be described later. This illumination light is irradiated through the window 18 toward the substrate side alignment mark 16 and the mask side alignment mark 17 of the glass substrate 11 and the metal mask 12. Then, the reflected light from the substrate side alignment mark 16 and the mask side alignment mark 17 is imaged by the CCD camera 24 that constitutes the imaging device 21.

  3 shows an imaging screen of the CCD camera 24, FIG. 3A shows an image when the positions of the glass substrate 11 and the metal mask 12 are shifted, and FIG. 3B shows the glass substrate. 11 shows an image when the positions of 11 and the metal mask 12 match. The substrate side alignment mark 16 is a substantially mirror-like reflector made of chromium or the like. For this reason, when the substrate side alignment mark 16 is imaged by the CCD camera 24, the substrate side alignment mark 16 is recognized as a white pattern P1 in the image as shown in FIGS. 3 (A) and 3 (B). . On the other hand, the mask alignment mark 17 is a through hole. For this reason, the illumination light is not reflected by the mask side alignment mark 17, and the light reflected by the surface of the metal mask 12 around the mask side alignment mark 17 is detected. For this reason, as shown in FIGS. 3A and 3B, the mask-side alignment mark 17 has a black pattern P2 in the image as compared with the surroundings.

  The image processing control device 40 performs image recognition processing such as normalized correlation pattern matching on the image from the CCD camera 24, and the relative position between the substrate side alignment mark 16 and the mask side alignment mark 17 is detected. The amount of movement of the substrate moving mechanism 42 is calculated. Based on this movement amount, the glass substrate 11 is moved by the actuator control device 41 via the substrate moving mechanism 42 so that the pattern P1 of the substrate side alignment mark 16 and the pattern P2 of the mask side alignment mark 17 coincide. Is done.

  When the glass substrate 11 is adjusted to the correct position with respect to the metal mask 12, the EL element is deposited by the deposition source 15. Since the metal mask 12 is provided with the opening 13 corresponding to the image pattern of the display, the organic EL film pattern having the same pattern as the opening 13 is transferred to the glass substrate 11.

  As described above, in the first embodiment of the present invention, the optical device 20 is provided with the coaxial epi-illumination device 22 and the oblique illumination device 23, and uses two illuminations of the coaxial epi-illumination and the oblique illumination. Then, alignment between the glass substrate 11 and the metal mask 12 is performed. When such two illuminations are used, reflected light from the substrate-side alignment mark 16 and the mask-side alignment mark 17 can be captured in a larger contrast image, and the glass substrate 11 and the metal mask 12 can be captured. The relative position can be detected with high accuracy. Thereby, even with an inexpensive metal mask 12 having a large surface roughness, the positions of the glass substrate 11 and the metal mask 12 can be correctly aligned. This will be described below.

  FIG. 4A schematically shows an image when the substrate-side alignment mark 16 and the mask-side alignment mark 17 are detected by the coaxial epi-illumination, and FIG. 4B is an oblique view in addition to the coaxial epi-illumination. An image when lighting is turned on is shown typically.

  As described above, since the substrate-side alignment mark 16 of the glass substrate 11 is a substantially mirror-like reflector, the coaxial epi-illumination from the coaxial epi-illumination device 22 is regularly reflected by the substrate-side alignment mark 16 and applied to the lens 25. Return. Therefore, when the substrate-side alignment mark 16 is imaged by irradiating the coaxial incident illumination, the substrate-side alignment mark 16 is recognized as a white pattern P1 in the image as shown in FIG. On the other hand, since the oblique illumination from the oblique illumination device 23 has a reflection angle, it does not enter the lens 25 even if it is reflected by the substrate side alignment mark 16. For this reason, the presence or absence of oblique illumination hardly affects the brightness of the pattern P1 of the substrate side alignment mark 16. Therefore, even if the oblique illumination is turned on in addition to the coaxial incident illumination, the brightness of the pattern P1 hardly changes as shown in FIG. 4B. However, when the oblique illumination is turned on, the overall brightness L1 increases. Therefore, as shown in FIG. 4B, when the oblique illumination is turned on, the contrast of the pattern P1 of the substrate side alignment mark 16 is lowered by the increase in the overall brightness L1.

  On the other hand, in the case of the mask side alignment mark 17, since the mask side alignment mark 17 is a through hole, the mask side alignment mark 17 does not reflect illumination, and the surface of the metal mask 12 around the mask side alignment mark 17. The light reflected by the lens reaches the lens 25. For this reason, as shown in FIG. 4A, the mask-side alignment mark 17 has a black pattern P2 in the image as compared with the surroundings. In the case of the metal mask 12, since the surface of the metal mask 12 is not mirror-like, the coaxial epi-illumination from the coaxial epi-illumination device 22 is scattered and the amount of light reaching the lens 25 is small. Therefore, with only the coaxial epi-illumination, as shown in FIG. 4A, the image on the mask surface is relatively dark and the contrast of the pattern P2 of the mask side alignment mark 17 is small. Here, in addition to the coaxial epi-illumination, when the oblique illumination is further turned on, as shown in FIG. 4B, the amount of reflected light on the mask surface increases and the overall brightness L1 increases. , The contrast increases.

  The following table shows the above relationship in a table.

  As can be seen from this table, for the image pattern P1 of the substrate side alignment mark 16, the contrast is large when the oblique illumination is turned off, and the contrast is reduced when the oblique illumination is turned on. For this reason, when detecting the pattern P1 of the image of the substrate side alignment mark 16, the position detection accuracy increases when the oblique illumination is turned off.

  On the other hand, the image pattern P2 of the mask side alignment mark 17 has a small contrast when the oblique illumination is turned off, and a contrast when the oblique illumination is turned on. For this reason, when detecting the pattern P2 of the image of the mask side alignment mark 17, the position detection accuracy increases when the oblique illumination is turned on.

  FIG. 5 is a flowchart for aligning the glass substrate 11 and the metal mask 12 in the first embodiment of the present invention. In this embodiment, the pattern P1 of the substrate side alignment mark 16 is imaged at the timing when the oblique illumination from the oblique illumination device 23 is turned off, and the pattern P2 of the mask side alignment mark 17 is imaged at the timing when the oblique illumination is turned on. This enables highly accurate position detection. It should be noted that when alignment is performed, the halogen light sources 26 and 29 of the coaxial incident illumination device 22 and the oblique illumination device 23 are always turned on, and the oblique illumination is turned on and off by opening and closing the shutter 32. Shall be controlled.

  In FIG. 5, when aligning the glass substrate 11 and the metal mask 12, first, the image processing control device 40 closes the shutter 32 and turns off the oblique illumination (step S1). As shown in FIG. 4A, when the oblique illumination is turned off, the image pattern P1 of the substrate side alignment mark 16 can be detected with a large contrast. Then, the image processing control device 40 inputs the image of the CCD camera 24 to the image processing control device 40 (step S2), and detects the position of the substrate side alignment mark 16 from the pattern P1 of the image of the CCD camera 24 (step S2). S3).

  When the position of the substrate alignment mark 16 is detected in step S3, the image processing control device 40 then opens the shutter 32 and turns on the oblique illumination (step S4). As shown in FIG. 4B, when the oblique illumination is turned on, the image pattern P2 of the mask side alignment mark 17 can be detected with a large contrast. Then, the image processing control device 40 inputs the image of the CCD camera 24 to the image processing control device 40 (step S5), and detects the position of the mask side alignment mark 17 from the pattern P2 of the image of the CCD camera 24 (step S5). S6).

  When the position of the mask-side alignment mark 17 is detected, the image processing control device 40 determines from the position of the substrate-side alignment mark 16 detected in step S3 and the position of the mask-side alignment mark 17 detected in step S6. A displacement amount between the glass substrate 11 and the metal mask 12 is calculated (step S7), and it is determined whether the displacement amount is within an allowable range (step S8).

  If the positional deviation amount is not within the allowable range, the image processing control device 40 calculates a corrected movement amount from the positional deviation amount, and transmits the corrected movement amount to the actuator control device 41 (step S9). The actuator control device 41 moves the substrate moving mechanism 42 based on the received movement amount (step S10), and returns to step S1.

  By repeating Steps S1 to S10, the amount of positional deviation between the glass substrate 11 and the metal mask 12 approaches the allowable range. If it is determined in step S8 that the positional deviation amount is within the allowable range, the process is ended.

  As described above, in the embodiment of the present invention, the pattern P1 of the substrate side alignment mark 16 is imaged with the oblique illumination turned off, and the pattern P2 of the mask side alignment mark 17 is imaged with the oblique illumination turned on. By doing so, the reflected light from the substrate-side alignment mark 16 and the mask-side alignment mark 17 can be captured in an image with a larger contrast, and the relative position between the glass substrate 11 and the metal mask 12 can be accurately determined. It can be detected.

  Note that the problem that the contrast of the pattern P2 of the mask-side alignment mark 17 in the through hole decreases due to the light being scattered only by the coaxial incident illumination depends on the surface roughness of the metal mask 12. In the case of a general iron-based alloy as the material of the metal mask 12, it is experimentally confirmed that the effect of improving the contrast by using oblique illumination is remarkable when the average surface roughness Ra is 0.2 μm or more. Has been. In addition, since this problem becomes more prominent as the distance (operating distance) between the metal mask 12 and the lens becomes longer, in the embodiment of the present invention, both are arranged inside and outside the vacuum vessel as in the organic EL vapor deposition apparatus. This is particularly effective when an operating distance of 100 mm or more is required.

  In addition, in an alignment apparatus to which the present invention is applied, focus adjustment by autofocus may be performed before taking an image for detecting the position of an alignment mark (for example, described in JP-A-2004-264404). ). In such an apparatus, focus adjustment is performed based on a differential signal of an image and a contrast value. In the embodiment of the present invention, since the contrast of the image increases, not only the position detection accuracy of the alignment mark can be improved, but also the accuracy and reliability of the autofocus can be improved.

<Second Embodiment>
In the first embodiment described above, the positions of the substrate-side alignment mark 16 and the mask-side alignment mark 17 are detected from images captured at different timings. For this reason, the operation time of the entire alignment operation becomes longer due to an increase in the number of times of imaging and switching time between turning on and off oblique illumination. In addition, when the imaging device 21 or the like vibrates and the captured image fluctuates, an error occurs in the relative position between the substrate-side alignment mark 16 and the mask-side alignment mark 17 calculated from images captured at different timings. The alignment accuracy may decrease.

  The second embodiment solves the above-described problem. In addition, since the structure of an apparatus is the same as 1st Embodiment, only a different part is demonstrated below.

  In FIG. 1, in the alignment of the glass substrate 11 and the metal mask 12, the glass substrate 11 is usually disposed on the side close to the optical device 20, so that the substrate side alignment mark 16 does not cover the mask side alignment mark 17. As described above, the diameter of the substrate side alignment mark 16 is set smaller than the diameter of the mask side alignment mark 17, and the position where the substrate side alignment mark 16 overlaps the mask side alignment mark 17 is set as a target value for alignment. There are many cases. As shown in FIG. 6, the image taken with both the coaxial illumination and the oblique illumination turned on while the substrate side alignment mark 16 is overlaid on the mask side alignment mark 17 is shown in FIG. Both alignment marks 17 have higher contrast than the surroundings. Therefore, with such an image, the position of the substrate-side alignment mark 16 and the mask-side alignment mark 17 can be accurately detected from one image.

  In the initial position detection, since the positional relationship between the substrate-side alignment mark 16 and the mask-side alignment mark 17 is unknown, the oblique illumination is switched on and off, and the substrate-side alignment mark 16 and the mask-side alignment mark 17 are switched. Although it is necessary to perform a separate detection process, the substrate-side alignment mark 16 and the mask-side alignment mark 17 can be expected to be in an overlapping position after the second and subsequent correction movements.

  Therefore, in the second embodiment, in the first position detection, the process of detecting the substrate-side alignment mark 16 and the mask-side alignment mark 17 separately is performed by switching on / off the oblique illumination, and the second and subsequent times. In this position detection, the substrate-side alignment mark 16 and the mask-side alignment mark 17 are detected simultaneously while the oblique illumination is turned on. Thereby, high speed and high accuracy can be realized.

  FIG. 7 shows a flowchart of the second embodiment of the present invention. In FIG. 7, when aligning the glass substrate 11 and the metal mask 12, first, the image processing control device 40 closes the shutter 32 and turns off the oblique illumination (step S101). Then, the image processing control device 40 inputs the image of the CCD camera 24 to the image processing control device 40 (step S102), and detects the position of the substrate side alignment mark 16 from the image of the CCD camera 24 (step S103).

  If the position of the substrate side alignment mark 16 is detected in step S103, the image processing control device 40 then opens the shutter 32 and turns on the oblique illumination (step S104). Then, the image processing control device 40 inputs the image of the CCD camera 24 to the image processing control device 40 (step S105), and detects the position of the mask side alignment mark 17 from the image of the CCD camera 24 (step S106).

  When the position of the mask-side alignment mark 17 is detected, the image processing control device 40 determines from the position of the substrate-side alignment mark 16 detected in step S103 and the position of the mask-side alignment mark 17 detected in step S106. A displacement amount between the glass substrate 11 and the metal mask 12 is calculated (step S107), and it is determined whether the displacement amount is within an allowable range (step S108).

  If the positional deviation amount is not within the allowable range, the image processing control device 40 calculates a corrected movement amount from the positional deviation amount, and transmits the corrected movement amount to the actuator control device 41 (step S109). The actuator control device 41 moves the substrate moving mechanism 42 based on the received movement amount (step S110).

  By the processing in steps S101 to S110, the substrate-side alignment mark 16 and the mask-side alignment mark 17 are overlapped. For this reason, the substrate side alignment mark 16 and the mask side alignment mark 17 can be simultaneously detected with high contrast while the oblique illumination is turned on.

  When the processing of steps S101 to S110 is completed, the image processing control device 40 inputs the image of the CCD camera 24 to the image processing control device 40 with the oblique illumination turned on (step S111), and from the image of the CCD camera 24. Then, both the position of the substrate side alignment mark 16 and the position of the mask side alignment mark 17 are detected (step S112). When the position of the substrate side alignment mark 16 and the position of the mask side alignment mark 17 are detected, the glass substrate 11 and the metal mask 12 are determined from the position of the substrate side alignment mark 16 and the position of the mask side alignment mark 17. (Step S113), the process returns to step S108.

  By repeating Step S108 to Step S113, the amount of positional deviation between the glass substrate 11 and the metal mask 12 approaches the allowable range. If it is determined in step S108 that the amount of positional deviation is within the allowable range, the process ends.

<Modification>
The present invention is not limited to the above-described embodiments, and various modifications and applications are possible without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the halogen light sources 26 and 29 are used for the coaxial incident illumination device 22 and the oblique illumination device 23, but other light sources such as LEDs (Light Emitting Diodes) may be used. In this case, it is desirable to switch on / off the oblique illumination device 23 by turning on / off the LED drive current instead of the shutter 32. Thus, it can be seen that the position detection accuracy of the substrate-side alignment mark 16 is improved when the oblique illumination is turned off, and the position detection accuracy of the mask-side alignment mark 17 is improved when the illumination is turned on.

It is a block diagram of the vapor deposition apparatus for organic EL displays incorporating the mask alignment apparatus of the 1st Embodiment of this invention. It is explanatory drawing of the light source in the mask alignment apparatus of the 1st Embodiment of this invention. It is explanatory drawing of the imaging screen of the alignment mark in the mask alignment apparatus of the 1st Embodiment of this invention. In the 1st Embodiment of this invention, it is explanatory drawing of the imaging screen of an alignment mark when oblique illumination is light-extinguished and turned on. It is a flowchart used for operation | movement description of the mask alignment apparatus of the 1st Embodiment of this invention. It is explanatory drawing of the imaging screen of the alignment mark in the mask alignment apparatus of the 2nd Embodiment of this invention. It is a flowchart used for operation | movement description of the mask alignment apparatus of the 2nd Embodiment of this invention.

Explanation of symbols

10: Vacuum container 11: Glass substrate 12: Metal mask 13: Opening 15: Deposition source 16: Substrate side alignment mark 17: Mask side alignment mark 18: Window 20: Optical device 21: Imaging device 22: Coaxial incident illumination device 23: Oblique illumination device 24: CCD camera 25: lens 26: halogen light source 27: light guide 28: half mirror 29: halogen light source 30: light guide 31: ring illumination head 32: shutter 40: image processing control device 41: actuator control device 42 : Substrate moving mechanism

Claims (3)

The substrate side alignment mark formed on the glass substrate and the mask side alignment mark formed on the mask are imaged, and the relative positional relationship between the glass substrate and the mask is determined from the captured images of the substrate side alignment mark and the mask side alignment mark. In a mask alignment apparatus that calculates and aligns the glass substrate and the mask based on the calculated relative positional relationship,
Imaging means for imaging the substrate-side alignment mark and the mask-side alignment mark;
Coaxial epi-illumination means for illuminating illumination light in a direction coaxial with the optical axis of the imaging means;
Oblique illumination means for illuminating illumination light from an oblique direction with respect to the optical axis of the imaging means;
Oblique illumination control means for controlling turning on and off of the oblique illumination means;
Using the image picked up by the image pickup means, the position of the mask side alignment mark and the position of the substrate side alignment mark are detected, and the detection position of the substrate side alignment mark and the detection position of the mask side alignment mark are detected. Based on the control means for calculating the amount of deviation between the glass substrate and the mask;
A mask alignment apparatus comprising: a substrate moving unit configured to align the glass substrate and the mask based on the calculated shift amount. The control means includes
First mark detection means for detecting a position of the substrate side alignment mark from an image taken by the imaging means in a state where the oblique illumination is turned off;
Second mark detection means for detecting a position of the mask side alignment mark from an image picked up by the image pickup means with the oblique illumination turned on;
Based on the position of the substrate-side alignment mark detected by the first mark detection means and the detection position of the mask-side alignment mark detected by the second mark detection means, the glass substrate and the mask A first alignment processing unit that calculates a displacement amount, and performs alignment between the glass substrate and the mask based on the calculated displacement amount;
The mask alignment apparatus according to claim 1, further comprising: The control means includes
Third mark detection means for detecting positions of both the substrate-side alignment mark and the mask-side alignment mark from an image picked up by the image pickup means with the oblique illumination turned on;
Based on the detected positions of the substrate-side alignment mark and the mask-side alignment mark detected by the third mark detection means, a displacement amount between the glass substrate and the mask is calculated, and based on the calculated displacement amount. And a second alignment processing means for aligning the glass substrate and the mask,
The mask alignment apparatus according to claim 2, wherein after the alignment by the first alignment processing unit, the alignment by the second alignment processing unit is performed.

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