JP4712358B2 - Mask frame combination body, substrate using the same, and mask alignment method - Google Patents

Description

  The present invention relates to a mask frame combination, and more particularly to a mask frame combination including auxiliary alignment means and a method of aligning a substrate using the mask frame combination.

  Various display devices are used for displaying images. Recently, various flat panel display devices that replace a conventional cathode ray tube, that is, a cathode ray tube (CRT), are used. Such flat panel display devices can be classified into self-luminous type and non-self-luminous type according to the light emission type. The self-luminous display device includes a flat cathode ray tube, a plasma display device (PDP), and a vacuum fluorescent display device. There are a field emission display device (FED), an electroluminescent display device (ELD), etc., and a non-self light emitting display device is a liquid crystal display device (Liquid Crystal Display). LCD).

  Among these, ELD, especially organic ELD, recombines electrons and holes injected into the organic thin film through the cathode and anode to form excitons, and light of a specific wavelength is generated by the energy from the formed excitons. This is a self-luminous display device that utilizes the phenomenon. The organic ELD can be driven at a low voltage, is light and thin, has a wide viewing angle, and has a high response speed.

  Such an organic EL device of organic ELD is composed of an anode, an organic film layer, and a cathode formed by being laminated on a substrate. As the substrate, a glass plate is usually used, but an elastic plastic plate or film may be used. As the anode, ITO (Indium Tin Oxide) is used, which is formed by vacuum deposition or sputtering. As the cathode, magnesium (Mg), lithium (Li) or the like having a small work function is mainly used. The organic film layer may be formed of various organic materials, but may be doped with a fluorescent dye or a phosphorescent dye in order to improve luminous efficiency. The organic film layer includes an organic light emitting layer (hereinafter referred to as EML), and holes and electrons are recombined in the organic EML to form excitons and light is generated. In order to further increase the luminous efficiency, holes and electrons must be transported more smoothly to the organic EML. For this reason, an electron transport layer (Electron Transport Layer: ETL) is disposed between the cathode and the organic EML. In addition, a hole transport layer (HTL) may be disposed between the anode and the organic EML, and a hole injection layer (Hole Injection Layer) may be disposed between the anode and the HTL. : HIL) may be disposed, and an electron injection layer (EIL) may be disposed between the cathode and the ETL.

  The process for forming the organic electroluminescent element is usually composed of a pre-process, a post-process, and a sealing process. The pre-process is a process of forming an ITO electrode on a substrate, for example, a glass substrate through, for example, a sputtering process, and the post-process is a process of forming an organic EML and a metal electrode by, for example, an evaporation method in a high vacuum state. Yes, it is performed using deposition equipment consisting of chamber, material evaporation source, thickness monitor, metal mask and so on. The sealing step is a step of sealing the organic light emitting device by inserting a desiccant in a vacuum or nitrogen atmosphere, for example, in order to extend the durability of the organic light emitting device that is very sensitive to moisture and oxygen in the air. It is.

  On the other hand, it is important to deposit an organic material or a metal material on the substrate at a high speed while maintaining a high vacuum in the chamber during the subsequent process. At this time, when an undesirable bend occurs between the metal mask and the substrate, the organic material or the metal material cannot be deposited on the substrate at a desired position. Therefore, the metal mask is warped due to thermal expansion and the substrate is warped due to its own weight. Must be maximally suppressed. Conventionally, various methods for reducing the warpage of the substrate due to such dead weight have been tried. In Patent Document 1, several masks are arranged on a mask frame, and the support points on the substrate are supported by using several alignment pins arranged in a cross shape on the mask frame. There has been proposed a method for decreasing the warpage of the substrate by increasing the resistance. However, maintaining the same flatness of several masks makes the process itself difficult, and when using such a method, the substrate and the mask are not in close contact with each other, and a total pitch error occurs. In particular, it has the disadvantage of causing poor deposition and increasing costs due to complicated manufacturing processes.

Further, in the prior art related to the alignment of the substrate and the mask, after the substrate is placed on the mask, the substrate or the mask is moved, and at the same time, a CCD (Charged Coupled Device) is used on the substrate and the mask. It is confirmed whether or not the formed alignment mark matches, and the substrate and the mask are aligned by completing the alignment process of the substrate and the mask. However, there is a possibility that an arrangement error of the substrate and the mask may occur in the process of closely arranging the substrate and the mask after the alignment confirmation, and it is difficult to precisely align the substrate and the mask. In the technique described in Patent Document 1, when the alignment pins are made of a shrinkable resin and pressure is applied on the substrate, the alignment pins can be slightly displaced in the longitudinal direction. In order to complete the alignment process, the alignment pins cannot actively move in a direction perpendicular to the longitudinal direction of the alignment pins while supporting the substrate. After placing the substrate on the pins, when the alignment between the substrate and the mask is not within the error range and realignment is required, the substrate must be raised and the alignment process must be re-executed from the beginning. When realignment is performed without raising the substrate, not only the surface of the substrate is damaged, but also precise alignment is difficult to be performed due to friction between the pins and the substrate during realignment. Therefore, as described above, the alignment apparatus and the alignment method according to the related art have a disadvantage that the alignment process must be performed again from the beginning after the substrate is lifted when realignment of the substrate and the mask is required. .
JP 2003-033086 A

  It is an object of the present invention to provide a mask frame combination having an improved structure so that alignment between the substrate and the mask is more easily performed.

  It is another object of the present invention to provide a method for aligning a substrate and a mask using a mask frame combination having the improved structure.

  According to one aspect of the present invention for achieving the above object, in addition to having a plurality of evaporation openings, a mask having one or more pinholes between the plurality of evaporation openings, A mask frame disposed on one side of the mask, and alignment assisting means disposed on one side of the mask frame on the opposite side of the surface on which the mask is disposed, the alignment assisting means being A plurality of openings corresponding to the plurality of vapor deposition openings formed in the mask and a length longer than the penetrating length of the pinhole formed at a position corresponding to one or more pinholes formed in the mask. A mask frame combination that is movable so that the one or more pins penetrate the one or more pinholes.

  According to another aspect of the present invention, the one or more pins are disposed between vertices of openings adjacent to each other among the openings of the alignment assisting means. Provide a combined body.

  According to still another aspect of the present invention, the one or more pins are further disposed between sides of openings adjacent to each other among the openings of the alignment assisting means. A frame combination is provided.

  According to still another aspect of the present invention, there is provided a mask frame combination wherein the shape of each pinhole corresponds to the shape of a cross section of the pin.

  According to still another aspect of the present invention, there is provided a mask frame combination in which each pinhole has a circular shape.

  According to yet another aspect of the present invention, there is provided a mask frame combination wherein the maximum cross-sectional area size of each pin is smaller than the pin hole cross-section size corresponding to each pin.

  According to still another aspect of the present invention, there is provided a mask frame combination wherein the end portions of the one or more pins are hemispherical and formed of an elastic material.

  According to still another aspect of the present invention, there is provided a mask frame combination wherein the alignment assisting means is capable of linear movement in a direction perpendicular to a longitudinal direction of the one or more pins.

  According to still another aspect of the present invention, there is provided a mask frame combination in which the alignment assisting means is capable of rotating with respect to one point on the alignment assisting means.

  According to still another aspect of the present invention, the alignment assisting means includes a protruding portion that forms a recessed groove portion along an outer end portion, and the recessed groove portion of the protruding portion can mesh with a lower end portion of the mask frame. A featured mask frame combination is provided.

  According to still another aspect of the present invention, it further includes fixing means for fixing and mounting the mask frame in the chamber, and when the concave groove portion of the protruding portion and the lower end portion of the mask frame mesh with each other, The lower plane is disposed on substantially the same plane as the lower plane of the alignment assisting means, thereby providing a mask frame combination.

  According to still another aspect of the present invention, there is provided a mask frame combination, wherein a cross-sectional area between the pins of the alignment assisting means is narrowed in a direction away from the substrate.

  According to still another aspect of the present invention, in the method for aligning a mask and a deposition substrate, an alignment assisting means including one or more pins each penetrating through one or more pinholes provided in the mask. Is moved in the longitudinal direction of the pins so that the one or more pins can support the deposition target substrate through the pin holes, and then the alignment assist on a plane perpendicular to the longitudinal direction of the pins. A method of aligning a mask and a deposition substrate is provided, wherein means is moved to align the deposition substrate and the mask.

  According to still another aspect of the present invention, the alignment of the mask and the deposition target substrate using the alignment assisting unit is further performed after the deposition target substrate is moved and the deposition target substrate is aligned with the mask. A method of aligning a mask and a deposition substrate is provided.

  The mask frame combination according to the present invention includes an alignment assisting means that is formed with one or more pins and can be moved up and down, and uses the alignment assisting means that is movable while the substrate is disposed. The combination can be aligned smoothly and easily.

  In addition, according to the method for aligning a substrate and a mask using the mask frame combination according to the present invention, the number of alignment steps can be greatly reduced, thereby shortening the work process and drastically reducing the cost.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a mask frame combination composed of a mask 10, alignment assisting means 20, and mask frame 30. The mask 10 includes a plurality of vapor deposition openings 13 so that a plurality of patterns of organic electric field elements can be vapor-deposited collectively on a large area substrate. Each of the vapor deposition openings 13 is maintained in an open state or a plurality of slits may be formed, but an organic material or a metal material from a vapor deposition source is formed in each vapor deposition opening 13. Is deposited on the substrate. Pinholes 11 are formed in portions between the respective vapor deposition openings 13. In FIG. 1, pinholes 11 are formed between the apexes of the vapor deposition openings 13 exemplarily formed in a square shape, but are additionally formed between the sides of the vapor deposition openings 13. Sometimes.

  Although the pinhole 11 can be formed to have various shapes, the pinhole 11 has a shape corresponding to the pin 21 so that a pin 21 (see FIG. 2B) described later can be smoothly inserted into the pinhole 11. It is desirable that both the pinhole 11 and the pin 21 are circular. The larger the number of pins 21 and corresponding pinholes 11, the more support points for supporting the substrate 40 (see FIG. 5) are desirable. However, it can be limited to an appropriate number depending on the design specifications. The position, number, and shape of the pinhole are not limited to the type shown in FIG.

3A and 3B show the relationship between the amount of warpage of the member and the support point. In FIG. 3A, a beam having a length L is supported at both ends, and in FIG. 3B, a beam having a length 2L is supported at both ends and the position of the center length L. Uniform distribution load per length due to the weight of the beam is w _o, flexural modulus of the beam is _EI, v A, _B represents a warp displacement (warp amount) in each case FIGS. 3A and 3B. If the moment curvature radius relationship is used in consideration of the boundary condition for each case and the distributed load due to the weight of the beam, the following formula can be obtained. That is, for the case of FIG. 3A _(v indicated by _A) and FIG. 3B _(v indicated by _B),

  A formula for the amount of warping is obtained. Here, the function indicated by <> is a singular function. In each case, the warpage amount and the maximum warpage amount at the position of 1/2 L from the end are as follows.

  In the case of FIG. 3B, compared with the case of FIG. 3A, the warpage amount at the position of 1/2 L from the end portion is reduced by about 60%, and the maximum warpage amount is reduced by about 58%. That is, the area of the substrate is increased in order to improve work production efficiency, but a structure in which support points that can support the substrate are arranged at appropriate positions despite the increase in the size of the substrate. By adopting, the warpage of the substrate due to the distributed load due to the increased weight can be significantly reduced. Therefore, as the number of pins 21 (see FIG. 2) supporting the substrate 40 (see FIG. 5) is increased between the openings, the error during deposition caused by the warpage of the substrate can be improved.

  However, there is a certain limitation on the number of pins 21, that is, the number of pinholes 11. As shown in FIG. 1, the mask 10 is fixedly attached to the mask frame 30 in a state where a tensile force is applied in the direction of the arrow using a method such as spot welding or seam welding. As shown in FIG. 2A, the mask frame 30 on which the mask 10 is mounted is placed on a mask holder 50 as a fixing unit having a fixing unit 51. The mask holder 50 is fixed to a vapor deposition apparatus (not shown) in a vapor deposition chamber (not shown). An organic material or a metal material is vapor-deposited in such a vapor deposition chamber. If the number of pinholes 11 exceeds an appropriate line, the mask 10 under a tensile force is being vapor-deposited. May be deformed by heat applied to the. Therefore, in order to prevent the mask 10 from being deformed during the process, the numbers of the pins 21 and the pinholes 11 are appropriately set.

  The mask frame 30 needs to be as thin as possible so as not to prevent the organic material or the metal material from being deposited on the substrate, and must have a strength enough to maintain the tensile force applied to the mask 10. Although the mask frame 30 may have a shape corresponding to the mask 10, it is usually desirable to have a frame shape that supports only the outer portion of the mask.

  2B and 2C show the alignment assisting means 20. The alignment assisting means 20 is disposed on the opposite side of the surface of the mask frame 30 on which the mask 10 is disposed. The alignment assisting means 20 includes a plurality of openings 23 at positions corresponding to the plurality of vapor deposition openings 13 (see FIG. 1) formed in the mask 10. It is desirable that the area of the opening 23 formed in the alignment assisting unit 20 is larger than the area of the vapor deposition opening 13 so that vapor deposition on the substrate is smooth. One or more pins 21 are formed at predetermined positions on one surface of the alignment assisting means 20 corresponding to the positions of the one or more pinholes 11. When the substrate 40 (see FIG. 5A) is disposed on the one or more pins 21, the end of the pin 21 is manufactured in a hemispherical shape to prevent the pins 21 from damaging the substrate 40. It is desirable that the resin be made of an elastic resin.

  Each cross-sectional area of one or more pins 21 needs to be smaller than each area of one or more pinholes 11. For example, when the shape of the one or more pins 21 and the pinhole 11 is circular, it is desirable that the diameter of the pinhole 11 is about 1 mm larger than the diameter of the pin 21. Actually, in the alignment process between the substrate 40 and the mask 10, the relative movement distance between them is about ± 100 μm. However, a sufficient tolerance at the time of the initial setting in consideration of the mounting error of the mask 10. It is desirable to leave

  1, 2B, 2C, 4, 5A, and 5B, the alignment assisting means 20 is arranged along the longitudinal direction of one or more pins 21 by operating means (not shown) that is an alignment means. In addition to being movable, the linear motion is possible in the plane perpendicular to the longitudinal direction of the one or more pins 21, and the rotational motion is centered on one point of the plane perpendicular to the longitudinal direction of the one or more pins 21. You can also. The length of the pin 21 must be longer than the penetration length of the pinhole 11 so that the pin 21 penetrates the pinhole 11 formed in the mask 10 and supports the substrate 40. Several protrusions 22 are formed at the outer end of the alignment assisting means 20. The alignment assisting means 20 includes, for example, a concave groove portion 24 inside the discharge portion 22, and when the alignment auxiliary means 20 is raised and lowered (see FIG. 5), the lower end portion of the mask frame 30 is placed in the concave groove portion 24. . The mask holder 50 may guide the protruding portion 22 when the alignment assisting means 20 is raised and lowered, and may guide the protruding portion 22 into the space formed between the mask holders 50, that is, the guide portion 35. As shown in FIG. 5A, when the alignment assisting means 20 is raised to the maximum extent possible, the lower end of the mask frame 30 meshes with the concave groove 24 of the protrusion 22, and at this time, the mask frame 30 is fixedly maintained. The lower plane of the mask holder 50, which is a fixing means, and the lower plane of the alignment assisting means 20 are located on the same plane.

  In addition, when the organic material and the metal material are vapor-deposited on the substrate 40, the alignment assisting unit 20 may block a traveling direction of the vapor deposition material so that a shadow effect that prevents uniform vapor deposition of the vapor deposition material on the substrate 40 does not occur. The shape of the alignment assisting means 20 is formed. For example, as shown in FIG. 2C, the cross-sectional area of the alignment assisting means 20 corresponding to the portion between the deposition openings 13 of the mask 10 is formed narrower in the direction away from the substrate 40, that is, the pin The cross-sectional area of the portion closest to the substrate 40 or the mask 10 as viewed from the plane perpendicular to the longitudinal direction of 21 is formed larger than the cross-sectional area of the other portions.

  5A and 5B show a plan view of the state in which the mask 10, the mask frame 30, and the alignment auxiliary means 20 are assembled and their operating states, and FIGS. 6A and 6B show the state of the present invention. An alignment process of the substrate 40 and the mask 10 according to an embodiment is illustrated.

  The substrate 40 is put into a vapor deposition chamber (not shown) by an arrangement means (not shown) (S101, S201). The step of putting the substrate 40 into the vapor deposition chamber is performed by an operation mechanism (not shown), for example, a device such as a robot arm. For example, the robot arm pre-aligns the substrate 40 put in the deposition chamber to a preset position so that the substrate 40 is moved to a position where the position alignment pin 21 is sensed (S102, S202). When the pre-alignment of the substrate 40 is completed, the alignment assisting means 20 that has been lowered is raised (S103, S203). A substrate holding means (not shown) of an operation mechanism such as a robot arm is used to lower the substrate 40 and bring one end of the alignment assisting means 20 raised, that is, one end of the pin 21 into contact with the substrate 40 to hold the substrate. By releasing the holding of the substrate by the means, the substrate 40 is placed on the alignment assisting means 20 (S104, S204).

  Here, according to the embodiment illustrated in FIG. 6A, which is also referred to as an “on contact” method, the substrate 40 and the mask 10 come into contact with each other by lowering the alignment assisting means 20 after step S104 (S105). . When the mask 10 and the substrate 40 come into contact with each other, an alignment observation device such as a CCD camera 61 is used to detect positional errors between the through holes 63 formed in the mask 10 and the alignment marks 62 and 64 formed on the substrate 40 and the mask frame 30. Etc., the alignment error between the substrate 40 and the mask frame (30) is measured (S106). After raising the alignment assisting means (20) (S107), the alignment error measured in step S106 is corrected by moving the alignment assisting means 20 in a direction to reduce the alignment error (S108). After correcting the alignment error, the alignment assisting means 20 is lowered and the substrate 40 is rearranged so as to contact the mask 10, and then the alignment error is measured again using the CCD camera 61 or the like (S110). If the remeasured alignment error satisfies a preset error range, the magnet unit (not shown) is lowered to bring the magnet unit and the substrate 40 into contact with each other (S111). If the set error range cannot be satisfied, the steps after step S107 are performed again. After the magnet unit is lowered and contacts the substrate 40, an alignment error may occur in this process. Therefore, the alignment error is measured using the CCD camera 61 or the like. If the re-measured alignment error satisfies the preset value, the deposition process is performed (S114). If the alignment error does not satisfy the preset value, the magnet unit is raised (S113) and then the steps after S107. Repeat the stage.

  On the other hand, according to another embodiment as illustrated in FIG. 6B, which is referred to as an “off contact” method, alignment assistance to a position where a sensing distance is maintained between the substrate 40 and the mask 10 after step S204. The means 40 is lowered (S205), and an alignment observation device 61 such as a CCD camera is used to observe a positional error between the alignment marks 62 and 64 formed on the substrate 40 and the mask frame 30 (S206). The sensing distance is a distance that the alignment observation device 61 such as a CCD camera can sense the alignment marks 62 and 64, and is determined by the resolution of the CCD camera 61 and the like. If the observed alignment error does not satisfy the preset alignment error (S207), the alignment assisting means 20 is moved to correct the alignment error (S208), and the steps after step S206 are performed again. In some cases, the method further includes a step (S209) of gradually lowering the alignment assisting means (S208) during the process of correcting the alignment error. If the observed alignment error satisfies a preset alignment error (S207), after the alignment assisting means 20 is completely lowered (S210), the magnet unit (not shown) is lowered to lower the magnet unit and the substrate. 40, and the alignment error is measured again using the CCD camera 61 or the like (S211). If the re-measured alignment error does not satisfy the preset value, the magnet unit is raised (S213), and the alignment auxiliary means 20 is raised at least by the sensing distance (S214), and the steps after step S206 are performed again. To do. On the other hand, if the alignment error satisfies the preset value, the deposition process is performed (S215). Such an alignment error correction by the off-contact method may reduce an operation error that may occur during the alignment process.

  Although the present invention has been described with reference to some exemplary embodiments illustrated in the accompanying drawings, this is merely exemplary, and those skilled in the art will appreciate that various modifications and equivalents can be made. It can be understood that it is possible to adopt the implementation form. Therefore, the true protection scope of the present invention should be determined only by the claims.

  The present invention is used as a mask frame combination that enables simple alignment in a process of patterning a deposit on a substrate by vapor deposition. The mask frame combination may be used in various semiconductor device manufacturing processes including a deposition process as well as a flat display element manufacturing process such as an organic electroluminescent element.

1 is a schematic perspective view of a mask frame combination according to an exemplary embodiment of the present invention. It is sectional drawing of the mask and mask frame which were cut | disconnected along line AA of FIG. It is a sectional side view of the alignment auxiliary | assistance means incised along line BB of FIG. It is a sectional side view of the alignment auxiliary | assistance means incised along line CC of FIG. It is a schematic diagram showing a beam of length per distributed load w _o is applied length L by its own weight. Is a schematic diagram showing a beam of 2L length per distributed load w _o by its own weight is added. It is an assembly sectional view of a mask, a mask frame, and an alignment auxiliary means. It is an operation | movement sectional drawing of a mask frame combination body in case an alignment assistance means exists in a raise state. It is an operation | movement sectional drawing of a mask frame combination body in case an alignment assistance means exists in a descent | fall state. , It is a flowchart which shows the alignment process of a mask and a board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mask 11 Pinhole 13 Evaporation opening 20 Alignment auxiliary means 21 Pin 22 Projection 23 Opening 24 Concave groove 30 Mask frame 35 Guide part 40 Substrate 50 Mask holder

Claims (12)

In addition to having a plurality of deposition openings, a mask having one or more pinholes between the plurality of deposition openings,
A mask frame disposed on one side of the mask;
Alignment assisting means disposed on one side of the mask frame and on the opposite side of the surface on which the mask is disposed,
The alignment assisting means is formed with a plurality of openings corresponding to a plurality of deposition openings formed in the mask and at positions corresponding to one or more pinholes formed in the mask. One or more pins longer than the penetration length of a hole, The mask frame combination body which can move so that the one or more pins may penetrate the one or more pin holes.   The mask frame combination according to claim 1, wherein the one or more pins are disposed between vertices of openings adjacent to each other among the plurality of openings of the alignment assisting means. .   The mask frame combination according to claim 2, wherein the one or more pins are further disposed between sides of the openings adjacent to each other among the plurality of openings of the alignment assisting means. body.   The mask frame combination according to claim 1, wherein the shape of the pinhole corresponds to the shape of a cross section of the pin.   The mask frame combination according to claim 4, wherein the pinhole has a circular shape.   2. The mask frame combination according to claim 1, wherein a size of a maximum cross-sectional area of the pin is smaller than a size of the cross-section of the pin hole corresponding to the pin.   2. The mask frame combination according to claim 1, wherein an end of the pin is hemispherical and is formed of an elastic material.   The mask frame combination according to any one of claims 1 to 7, wherein the alignment assisting means is capable of linear movement in a direction perpendicular to a longitudinal direction of the one or more pins.   9. The mask frame combination according to claim 8, wherein the alignment assisting means is capable of rotating with reference to one point on the alignment assisting means.   8. The alignment assisting means includes a protruding portion that forms a recessed groove portion along an outer end portion, and the recessed groove portion of the protruding portion meshes with a lower end portion of the mask frame. 2. A mask frame combination according to item 1.   And a fixing unit configured to fix and attach the mask frame in the chamber. When the concave groove of the protrusion and the lower end of the mask frame are engaged with each other, the lower plane of the fixing unit is the lower plane of the alignment assisting unit. The mask frame combination according to claim 10, wherein the mask frame combination is arranged on substantially the same plane.   The mask frame combination according to any one of claims 1 to 7, wherein a cross-sectional area between the pins of the alignment assisting means is narrower in a direction away from the substrate.

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