JP5525866B2 - Mask member cleaning device - Google Patents

Description

  The present invention relates to a mask member cleaning apparatus for cleaning a metal mask member after vacuum deposition on a substrate surface.

    For example, in manufacturing an organic EL display, a pattern of light emitting elements that emit R, G, and B is formed on the surface of a panel substrate. Each color light emitting element is formed of an organic material, and the pattern is generally formed by a vacuum deposition method. A mask member is used for this vacuum deposition. The mask member is composed of a mask plate and a mask frame. The mask plate is made of a nickel-cobalt alloy or the like and is formed of a metal thin plate having a thickness of about several tens of μm. The mask pattern has a large number of minute through holes at minute pitch intervals. The mask plate is made of a rectangular member, and a mask frame is attached to prevent the deformation and damage of the mask plate at the time of handling in order to maintain its shape.

  When performing vacuum deposition on the panel substrate, the mask member is disposed oppositely in a vacuum chamber with the mask member aligned on the surface of the panel substrate, and vapor deposition material is evaporated from the evaporation source. A predetermined thin film light emitting element pattern is formed on the surface of the panel substrate. Therefore, in the case of configuring an organic EL display, a pattern of thin film light emitting elements of three colors of R, G, and B is formed on the surface of the panel substrate.

  During vacuum deposition, the deposition material adheres not only to the panel substrate but also to the mask member. When vapor deposition is performed a plurality of times using the same mask member, the vapor deposition material attached to the surface of the mask member grows in a laminated state, resulting in an increase in thickness. As described above, when the thickness of the vapor deposition material is increased, the quality of the product is deteriorated, for example, the pattern shape due to the through holes is changed. Therefore, when vacuum deposition is performed a predetermined number of times using a mask member, the mask member is cleaned or washed to remove the deposited material adhering to the surface and perform regeneration.

  As a cleaning method of the mask member, there is a wet type ultrasonic cleaning performed by immersing the mask member in a cleaning tank storing a solvent. However, if the mask member is immersed in the cleaning liquid for a long time, the mask plate may be damaged due to the influence of heat from the ultrasonic wave, and the cleaning tank may be damaged, increasing the burden of the drainage treatment. There are problems such as.

  As another cleaning method for the mask member, a dry cleaning method has been conventionally known, as is apparent from the description of Patent Document 1, for example. That is, by irradiating the mask plate constituting the mask member with a pulse of laser light, the vapor deposition material that is in the form of a film and adheres to the surface of the mask plate is peeled off and collected. This peeling from the mask plate is caused by the vibration of the laser beam acting on the mask plate. In order to make the pulse of the laser beam irradiated to the mask plate a minute spot, the spot diameter is reduced by a condenser lens. The entire surface of the mask plate is dry cleaned by moving it in the X and Y directions along the surface of the mask plate.

JP 2006-192426 A

  The mask plate has a large number of minute through holes, and these minute through holes are arranged vertically and horizontally with a predetermined pitch interval. Therefore, when the mask plate is irradiated with the laser beam, the irradiation position is determined by the mask at the part where the minute through hole exists, the part where the minute through hole does not exist, and the boundary part between the minute through hole and the part without the through hole. The energy of the laser beam acting on the plate changes. Therefore, even if there is no change in the power of the irradiated laser light, the peeling efficiency of the vapor deposition material from the mask plate changes depending on the irradiation position. In particular, when the laser beam is irradiated to the minute through holes, the peeling efficiency is lowered. That is, peeling unevenness may occur due to the relationship between the irradiation spot of the laser beam and the position of the minute through hole of the mask plate.

  By the way, when cleaning the mask member, the vapor deposition material is also attached to the boundary between the mask plate and the mask frame and the surface of the mask frame. For this reason, the cleaning liquid was used after the dry cleaning as well as the dry cleaning. Wet cleaning will be performed. Therefore, even if there is some decrease in peeling efficiency or uneven peeling during dry cleaning, there is no particular problem from the viewpoint of cleaning the mask member. However, if there is any peeling residue of the vapor deposition material on the mask plate, it will be carried over to the wet cleaning process, resulting in a decrease in the recovery rate of the vapor deposition material and a high degree of contamination of the cleaning liquid. Even if wet cleaning is performed at a later stage, it is desirable to maximize cleaning efficiency as long as dry cleaning is performed.

  The present invention has been made in view of the above points, and an object of the present invention is to improve the cleaning efficiency by dry cleaning using laser light and to suppress the occurrence of uneven cleaning.

In order to achieve the above-mentioned object, the present invention removes the vapor deposition material adhering to the vapor deposition mask member composed of a mask plate having a lattice-like mask plate by drilling minute through holes with a predetermined pattern. In order to accomplish this, an apparatus for irradiating a laser beam from a laser beam irradiating means and scanning the surface of the mask plate with the laser beam to remove the vapor deposition material and clean the mask member, An alignment mark recognizing unit for recognizing an alignment mark provided at a predetermined position of the mask member, and depending on the position of the mask member detected by the alignment mark recognizing unit, the laser beam irradiation unit applies the mark to the mask member. that the irradiation position of the laser light is configured to include a control means for controlling such that the intersections of the grid of the mask plate It is an aspect of the.

  In irradiating the mask plate with laser light, the irradiation position is set to a position where the vapor deposition material can be peeled off as efficiently as possible from the mask plate. A large number of minute through holes are formed in the mask plate, and these minute through holes are regularly arranged. Therefore, in order to irradiate the laser beam to the position with the highest peeling efficiency, it is necessary to appropriately set the irradiation start position of the laser beam and the interval between the irradiation pulses. For this reason, alignment is performed between the mask member and the laser beam irradiation means before dry cleaning. Generally, when manufacturing an organic EL display, thin film light emitting elements of R, G, and B colors are formed on a panel substrate so as to have a predetermined pattern. The mask members are stacked on the panel substrate. In order to align between the panel substrate and the mask member, each color mask member is provided with an alignment mark at a predetermined position. In the present invention, this alignment mark is used as a clue to recognize the position of the mask member.

  The alignment mark is detected, and the laser beam irradiation means and the mask member are aligned. For this purpose, alignment mark recognizing means is provided, and the alignment mark recognizing means recognizes an image of the alignment mark of the mask member. The alignment between the laser light irradiation means and the mask member can be optically performed by the laser light irradiation means, and the position of at least one of the mask member and / or the laser light irradiation means can be adjusted. For example, the mask member is supported by a support member, and the support member is provided with a position adjustment mechanism composed of two orthogonal axes. If the alignment mark is deviated from the reference position, the position adjustment mechanism is operated to Adjustments can be made. In this case, the mask member to be cleaned can be arranged at a preset reference position. The support member can be configured to support the mask member in a horizontal state, or may be configured to support the mask member in an upright state such as a vertical state.

  The irradiation position of the laser beam to the mask member by the laser beam irradiation means is a position where the vapor deposition material adhering to the mask plate is efficiently peeled and peeling unevenness is minimized. The mask plate is provided with minute through holes for transferring the mask pattern to the panel substrate with a predetermined pitch interval. For this purpose, the mask plate is generally in a lattice shape. When the laser beam is irradiated to the grating portion, the energy of the laser beam does not escape from the through-hole, but almost the whole acts on the mask plate. By irradiating the lattice part as much as possible, the peeling efficiency is increased and quick dry cleaning is possible. Because of the relationship between the spot diameter of the laser beam and the size of the micro-penetration hole, the laser beam is irradiated at each crossing portion of the lattice. It is more desirable to irradiate one or more places with laser light.

  The panel substrate is vapor-deposited by using three types of mask members for each color of R, G, and B. For these three types of mask members, the positions of the minute through holes in each mask plate are different. Therefore, when performing dry cleaning of each mask member, the irradiation position of the laser beam must be adjusted. In view of this, the control device holds data on the laser beam irradiation position and interval for these various mask members, reads out this data in accordance with the type of the mask member, and outputs the laser beam by the laser beam irradiation means. The irradiation position is controlled.

  Further, in the same dry cleaning apparatus, not only the three types of mask members R, G, and B are dry cleaned, but also mask members of different types and sizes may be cleaned. In the case where the sizes and pitch intervals of the minute through holes are different, it is necessary to change the interval of the laser light irradiation positions. The frequency of the irradiation pulse itself can be controlled, but the scanning speed can be changed with the pulse frequency kept constant. That is, when the laser beam irradiation interval is increased, the laser beam scanning speed is increased, and when the laser beam irradiation interval is decreased, the laser beam scanning speed is decreased.

  In performing dry cleaning by irradiating the mask plate with laser light by the laser light irradiation means on the mask member, by controlling the irradiation position of the laser light on the mask plate, the separation efficiency is high and the unevenness of the separation is achieved. Can be minimized.

In this invention, it is a top view of the mask member used as the object of cleaning. It is a principal part expanded sectional view which shows the state which mounts | wears with a mask member and vacuum-deposits on the substrate surface. It is a schematic block diagram of a dry cleaning apparatus. It is explanatory drawing which shows the relationship between a mask board and the spot of the laser beam to this mask board.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, in FIG. 1, reference numeral 1 denotes a mask member, and the mask member 1 is composed of a rectangular mask plate 2 and a mask frame 3 made of a frame provided around the mask plate 2. The mask plate 2 has a mask pattern region 4 in which a large number of minute through holes 4a are arranged vertically and horizontally with a predetermined pitch interval. Therefore, the mask plate 2 has vertical and horizontal lattices 4b that define the minute through holes 4a. Have.

  As shown in FIG. 2, the mask member 1 is used to form a predetermined pattern on the surface of the panel substrate 5 made of transparent thin glass, and constitutes an organic EL display. It is used to form a pattern of light emitting elements that emit light in R, G, and B. Each color light-emitting element is formed of an organic material, and the pattern is formed by a vacuum deposition method. The panel substrate 5 is disposed opposite to the heated evaporation source in the vacuum evaporation chamber, thereby evaporating the evaporation material from the evaporation source and forming the evaporation film 6 on the surface of the panel substrate 5. . The mask member 1 is used to form a film formation pattern on the panel substrate 5.

  The mask member 1 has its mask plate 2 superimposed on the panel substrate 5. When vacuum deposition is performed, the vapor deposition film 6 made of a vapor deposition material adheres to the entire mask member 1 including the mask frame 3 as well as the mask plate 2. The deposition of the vapor deposition material is deposited every time the number of vapor depositions is repeated, and when the vapor deposition material is deposited to a certain extent, the pattern shape by the minute through holes 4a is changed, and the pattern transfer accuracy is lowered. Therefore, the vapor deposition material film 7 adhering to the surface of the mask member 1 must be removed by performing cleaning before the pattern shape by the minute through holes 4a is changed. The vapor deposition material adheres to the entire surface 1a facing the evaporation source during vacuum vapor deposition, including the wall surface of the minute through hole 4a in the mask plate 2, and the vapor deposition material film 7 also adheres to the mask frame 3. . In addition, some vapor deposition material may adhere to the back side 1 b of the mask member 1.

  Here, in order to remove the vapor deposition material film 7 adhering to the surface of the mask plate 2, dry cleaning is performed by laser light irradiation. The overall schematic configuration of this dry cleaning apparatus is shown in FIG. In this dry cleaning apparatus, dry cleaning is performed by irradiating the mask pattern region 4 of the mask plate 2 constituting the mask member 2 with laser light in a state where the mask member 2 is set in the vertical direction.

  The dry cleaning stage S is provided with a pair of posts 10 and 10, and an elevating member 11 is provided between the posts 10 and 10. The raising / lowering member 11 is comprised from the side part guide parts 11a and 11a and the bottom receiving part 11b. Slide guides 12 are provided on the side guide portions 11a, and the mask member 1 can be inserted into the slide guides 12 on both the left and right sides of the mask frame 3, and the mask member 1 has a bottom receiving portion 11b. And is supported by the elevating member 11. Therefore, the elevating member 11 serves as a support member that supports the mask member 1 so as to be movable up and down. The side guide portion 11a of the elevating member 11 is engaged with the guide groove 10a of the post 10 and moves up and down along the guide groove 10a. Therefore, the mask member 1 is supported in a vertical state.

  The dry cleaning is performed by spot-rapidly heating the mask member 1 supported by the elevating member 11. For this purpose, a laser oscillator 13 for emitting a pulse of laser light is provided. The optical path of the pulsed laser beam from the laser oscillator 13 is bent by the scanning optical system 14 and irradiated to the mask member 1. Here, the scanning optical system 14 includes, for example, a condenser lens, a galvano mirror, and an actuator for driving the condensing lens. The laser oscillator 13 and the scanning optical system 14 constitute a laser light irradiation unit 15.

  Here, with respect to the mask member 1, at least the entire mask pattern region 4 on the mask plate 2 is dry-cleaned. Since the mask member 1 is mounted in a vertical state, the scanning optical system 14 sets the irradiation position of the laser pulse with respect to the mask plate 1 in the horizontal direction (main scanning direction) and the vertical direction, that is, the sub-direction orthogonal to the main scanning direction. Although scanning is performed in the scanning direction, the movement of the laser spot in the main scanning direction and the sub-scanning direction is performed by the scanning optical system 14.

  The scanning of the laser beam is performed on the surface 1a of the mask member 1, and the deposits on the surface of the mask plate 2 are crushed and released from the mask plate 2, but are thus released. A recovery means for recovering debris and flakes of the deposited vapor deposition material is provided. This recovery means has a long nozzle 17 as a negative pressure suction means for applying a negative pressure suction force so as to cover the entire length of the mask member 1 in the width direction. The long nozzle 17 is a suction nozzle having a slit-like nozzle opening having a length extending over the entire length in the width direction of the mask member 1 held by the elevating member 11.

  The long nozzle 17 may be fixed at a position that does not hinder the laser irradiation of the post 10. Alternatively, a moving mechanism (not shown) may be moved to a position near the lower side of the irradiation position, that is, to a position where the efficiency of collecting the peeled substance is substantially maximized, in accordance with the laser irradiation position.

  By the way, as already described, the mask plate 2 of the mask member 1 has the minute through holes 4a formed in the mask pattern region 4, and the periphery of the minute through holes 4a is a lattice portion 4b. The laser beam applied to the mask plate 2 becomes a minute spot in order to concentrate energy, and the whole or a part of the minute spot S is as shown in FIG. If it irradiates in the area | region of the micro through-hole 4a, the energy for that will not act on the mask board 2. FIG. As a result, the deposited vapor deposition material from the surface of the mask plate 2 cannot be efficiently peeled / removed. On the other hand, as shown in FIG. 4 (b), when the minute spot S is irradiated onto the grating portion 4b of the mask plate 2, especially when the intersection of the vertical and horizontal gratings is irradiated, almost the entire power of the laser beam is obtained. As a result of acting on the mask plate 2, the deposition efficiency of the deposited vapor deposition material is higher than in the case shown in FIG.

  As described above, depending on the irradiation position of the laser light applied to the mask plate 2 from the laser oscillator 13 constituting the laser light irradiation means 15 via the scanning optical system 14, there is a difference in the separation efficiency of the deposited vapor deposition material. become. Further, uneven peeling may occur depending on the irradiation position of the laser beam. Here, from the viewpoint of peeling efficiency and prevention of damage to the mask plate 2, the laser beam is irradiated as much as possible to the intersection of the vertical and horizontal lattices of the mask plate 2.

  Here, the mask plate 2 is fixed at a certain position, the laser beam irradiation start position is set as a reference position of the mask plate 2, the laser beam scanning direction is set, and the laser beam irradiation interval is controlled. Thus, it becomes possible to irradiate the desired position of the mask plate 2 with the laser beam from the laser oscillator 13. For this purpose, it is first necessary to perform alignment between the laser beam irradiation means 15 and the mask member 1 supported by the elevating member 11 by the slide guide 12.

  As shown in FIG. 1, the mask member 1 is provided with alignment marks M at the four corners of the mask frame 3. Therefore, these alignment marks M are photographed by the image pickup means 20 and image processing is performed to detect a deviation of each alignment mark M from the reference position, and the position adjustment means 21 performs fine position adjustment. Can be done. The specific configuration of the position adjusting mechanism of the mask member 1 by the position adjusting means 21 is well known in the art, and illustration and description thereof will be omitted.

  Therefore, the position adjustment means 21 adjusts the position of the mask member 1 by driving the position adjustment means 21 based on a signal related to the position of the alignment mark M by the imaging means 20 to place the mask member 1 at a predetermined position. Can do. As a result, the posture state of the mask plate 2 at the time of dry cleaning becomes constant, and the scanning direction of the laser light is set.

  On the other hand, the mask member 1 is different in the position of the minute through holes 4a depending on the R, G, B use, but the three types of mask members 1 used for the same panel substrate are each of the minute through holes 4a in the vertical and horizontal directions. The pitch interval is generally constant. Therefore, the R, G, B mask members formed on the same panel substrate 5 have different laser beam irradiation start positions, although the laser beam irradiation pulse intervals are constant. In the case of mask members used for panel substrates of different sizes or types, the laser beam irradiation start position and the laser beam irradiation pulse interval are different.

  Here, the scanning optical system 14 is composed of a galvanometer mirror, and scans the laser beam in the main scanning direction. If the initial position of the galvanometer mirror and the rotation speed are changed, the scanning optical system 14 can be moved to an arbitrary position. The laser beam can be irradiated at an arbitrary interval. Therefore, the scanning start position of the laser beam and the irradiation pulse interval by the scanning optical system 14 can be freely adjusted according to the type of the mask member to be dry-cleaned.

  In order to perform dry cleaning of the mask member 1 using the dry cleaning apparatus having the above configuration, the mask frame 3 of the mask member 1 is supported by being inserted into the side guide portion 11a of the elevating member 11, and the mask member 1 is supported. 1 is held at a predetermined height position. In this state, the imaging means 20 images the alignment mark M of the mask member 1. Here, the imaging means 20 can detect the most accurately when all of the four alignment marks M provided on the mask member 1 are photographed, but by detecting at least two alignment marks M, Position detection can be performed. When the position of the alignment mark M is deviated from the reference position, the position adjustment means 21 is driven to adjust the mask member 1 to a predetermined position. As a result, the posture state of the mask plate 2 becomes constant, and the scanning direction of the laser light is set.

  The laser beam irradiation start position varies depending on the type of the mask member 1. Even if it is a mask member used for the same panel board | substrate 5, the position of the micro through-hole 4a differs in the thing for R, G, B. Therefore, in the case of the three types of mask members 1 used on the same panel substrate, only the laser beam irradiation start position is different. For mask members used for panel substrates of different sizes or types, not only the irradiation start position but also the irradiation pulse interval of the laser light is adjusted. For this purpose, not only the initial position of the galvanometer mirror but also the rotational speed is changed. In order to shorten the laser light irradiation interval, the rotational speed of the galvanometer mirror is slowed down. To increase the laser light irradiation interval, the rotational speed of the galvanometer mirror is increased.

  When the position of the mask member 1 is detected and the scanning optical system 14 is controlled to set the scanning start position of the laser light and the rotation speed of the galvano mirror, a laser light pulse is emitted from the laser oscillator 13. By this laser light, a minute region of the mask member 1 is instantaneously heated. As a result, the deposited vapor deposition material can be peeled off from the surface of the mask plate 2, and the vapor deposition material that is peeled off and floats by the action of the long nozzle 17 is collected. Further, by this suction force, it is possible to separate the vapor deposition material partially attached to the mask plate 2 while floating from the mask plate 2. Then, the laser beam spot is moved in the main scanning direction at a predetermined speed by the scanning optical system 14, so that the laser beam is focused on the grating portion 4 b on the mask plate 2, particularly on the part including the intersecting part of the grating. The spot is irradiated, and the vapor deposition material can be uniformly peeled and recovered from the mask plate 2 with high efficiency.

  When the scanning of the laser beam for one main scanning line is performed, the scanning optical system 14 is moved by one line in the sub scanning direction. At this time, scanning in the main scanning line is performed in the direction opposite to the previous scanning. As a result, the speed of operation is ensured and efficient cleaning is possible.

  When the scanning of the entire area of the mask plate 2 is completed and the dry cleaning for the mask plate 2 is completed, the mask member 1 is taken out from the elevating member 11 and a new mask member 1 is mounted on the elevating member 11. In the mask member 2 after the dry cleaning, the vapor deposition material is still attached to the mask frame 3, and the vapor deposition material may not be completely removed from the mask plate 2. Therefore, it is desirable to perform wet cleaning by immersing in a cleaning solution after dry cleaning is completed. Since most of the vapor deposition material is removed from the mask plate 2 in advance by dry cleaning, the wet cleaning may be performed in a short time, and the degree of contamination of the cleaning liquid with the vapor deposition material is reduced.

  If the size of the mask plate 2 is larger than the range that can be scanned by the scanning optical system 14, the mask plate 2 of the mask member 1 can be divided into a plurality of regions and irradiated as described above. In this case, the mask plate 2 and the scanning optical system 14 may be moved relative to each other. That is, the mask member 1 may be moved in the Z or Y direction in FIG. 3 by the elevating member 11 or a driving mechanism (not shown), and the scanning optical system 14 may be moved in the X and Z directions by a driving mechanism (not shown). Alternatively, both may be moved.

  As described above, the laser beam to the mask plate 2 in the mask member 1 can be efficiently applied, and dry cleaning can be performed efficiently and quickly, and damage to the mask plate 2 is minimized. Therefore, dry cleaning can be performed without causing uneven peeling.

DESCRIPTION OF SYMBOLS 1 Mask member 2 Mask board 3 Mask frame 4 Mask pattern area | region 4a Micro through-hole 4b Grating part 10 Post 11 Lifting member 13 Laser oscillator 14 Scanning optical system 15 Laser beam irradiation means 17 Long nozzle

Claims (5)

In order to remove the vapor deposition material adhering to the vapor deposition mask member composed of the mask plate having the lattice-like mask plate by drilling the fine through holes with a predetermined pattern, the laser light from the laser light irradiation means is used. In an apparatus for irradiating and scanning the surface of the mask plate with this laser light to peel off the vapor deposition material and clean the mask member,
An alignment mark recognition means for recognizing an alignment mark provided at a predetermined position of the mask member;
Control means for controlling the irradiation position of the laser light to the mask member by the laser light irradiation means to be an intersection of the lattices of the mask plate according to the position of the mask member detected by the alignment mark recognition means A cleaning device for a mask member, characterized by comprising: A position adjusting hand for adjusting a position of at least one of the mask member and the laser beam irradiation means, and the control means is configured to adjust the mask member and the laser by the position adjusting means based on image recognition of the alignment mark. washing apparatus of the mask member according to claim 1, characterized in that a configuration in which relatively correcting the position of the light irradiating means. The irradiation position of the laser beam is controlled by the control means, washing apparatus of the mask member according to claim 1 or claim 2, characterized in that a position avoiding the small hole. The laser beam irradiation position is washing apparatus according to claim 3, wherein the mask member, characterized in that a configuration in which a portion of the grid of the mask plate to the mask member by the laser beam irradiation means. 5. The mask according to claim 1, wherein the mask member is supported in a vertical state with respect to the elevating member, and the scanning optical system uses a galvanometer mirror. washing apparatus of the member.

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