Frame manufacturing method and frame

Abstract

The invention relates to a frame manufacturing method and a frame. A frame manufacturing method according to the present invention is used in a connector of a mask for OLED pixel formation and a frame, the method comprising the steps of: (a) adhering a first surface of a metal sheet to a moving plate; (b) forming a plurality of mask cell regions on a second surface opposite to the first surface of the metal sheet and manufacturing a cell sheet portion; (c) connecting the unit sheet portion to an edge frame portion, the edge frame portion including a hollow region, after which the unit sheet portion is stretched in a lateral direction in a state of clamping an edge of the unit sheet portion and connected to the edge frame portion as a comparative example, the unit sheet portion is stretched in the lateral direction, and the edge frame portion is connected to the edge frame portion. The maximum value of the residual stress value left in any point of the edge of the unit sheet part is smaller than the maximum value of the residual stress value left in any point of the edge of the unit sheet part of the comparison example.

Description

Technical Field

[0001] The present invention relates to a frame manufacturing method and a frame. More specifically, the frame is used in a mask-frame connector, wherein the connector includes a mask formed with a high-resolution mask pattern, can stably form a mask without deformation, and can accurately align each mask unit. Background Art

[0002] As a technology for forming pixels in the OLED (Organic Light Emitting Diode) manufacturing process, the FMM (Fine Metal Mask) method is mainly used. In this method, a thin film metal mask (Shadow Mask) is closely attached to a substrate and organic matter is deposited at a desired position.

[0003] In the existing OLED manufacturing process, after the mask is manufactured into a strip shape, a plate shape, etc., the mask is welded and fixed to the OLED pixel evaporation frame and used. One mask can have multiple units corresponding to one display. In addition, in order to manufacture large-area OLEDs, multiple masks can be fixed to the OLED pixel evaporation frame. During the process of fixing them to the frame, each mask is stretched to make it flat. Adjusting the stretching force to make the entire part of the mask flat is a very difficult task. In particular, in order to flatten each unit while aligning the mask pattern with a size of several to tens of μm, the following difficult task is required: while finely adjusting the stretching force applied to each side of the mask, the alignment status is confirmed in real time.

[0004] Despite this, the process of securing multiple masks to a single frame still presents problems with poor alignment between masks and between mask units. Furthermore, during the process of welding the masks to the frame, the mask film is too thin and has a large surface area, causing the mask to sag or twist under the load. Furthermore, wrinkles and burrs generated at the welded portions during welding can lead to misalignment of the mask units.

[0005] In ultra-high-definition OLEDs, existing QHD image quality is 500-600 PPI (pixels per inch), with pixel sizes reaching approximately 30-50 μm. 4K UHD and 8K UHD have even higher resolutions, such as -860 PPI and -1600 PPI. Given the pixel size of ultra-high-definition OLEDs, alignment errors between units must be reduced to a few μm. Exceeding this error will result in defective products, potentially leading to extremely low yields. Therefore, it is necessary to develop technologies that prevent mask deformation, such as sagging or twisting, and ensure precise alignment, as well as technologies for securing the mask to the frame. Summary of the Invention

[0006] Technical issues

[0007] Therefore, the present invention is proposed to solve the many problems of the prior art as described above, and its purpose is to provide a frame manufacturing method and a frame, which is used in a connector between the mask and the frame, can support and move the mask stably without deformation, prevent deformation such as sagging or twisting of the mask, and can accurately align it.

[0008] Another object of the present invention is to provide a frame manufacturing method that can clearly perform alignment between mask units and more clearly form a frame edge portion.

[0009] However, these technical problems are only exemplary and are not intended to limit the scope of the present invention.

[0010] Technical Solution

[0011] The above-mentioned object of the present invention can be achieved through a frame manufacturing method, wherein the frame is used in a connector between a mask and a frame for forming OLED pixels, and the method includes the following steps: (a) bonding the first side of a metal sheet to a movable plate; (b) forming a plurality of mask unit areas on the second side opposite to the first side of the metal sheet and manufacturing a unit sheet portion; (c) connecting the unit sheet portion to an edge frame portion, wherein the edge frame portion includes a hollow area, and when the process of stretching the unit sheet portion in a side direction and connecting the unit sheet portion to the edge frame portion in a state of clamping the edge of the unit sheet portion is used as a comparative example, after the step (c), the maximum value of the residual stress value remaining at any point on the edge of the unit sheet portion is less than the maximum value of the residual stress value remaining at any point on the edge of the unit sheet portion of the comparative example.

[0012] In the step (a), the movable plate and the metal sheet may be bonded together by interposing a dry film resist layer (DFR layer).

[0013] The step of applying a tensile force to the side direction of the unit sheet portion may include the following steps: (1) contacting the movable plate and the metal sheet at a temperature at least higher than room temperature; (2) bonding the movable plate and the metal sheet during the process of the temperature decreasing to room temperature.

[0014] The step (1) may include sandwiching a temporary bonding portion between the movable plate and the metal sheet, and raising the process temperature to at least a level where the bonding strength (push-pull strength) of the temporary bonding portion reaches 0 to 5 kgf / cm 2The step (2) includes lowering the process temperature to at least a temperature where the bonding strength of the temporary bonding portion is greater than 5 kgf / cm 2 and bonding the metal sheet to the moving plate.

[0015] The movable plate may include at least one material selected from the group consisting of glass, silica, quartz, alumina (Al2O3), borosilicate glass, zirconia, silicate ceramic, titanium (Ti), molybdenum (Mo), silver (Ag), copper (Cu), platinum (Pt), gold (Au), polyimide, and polymer, or a material obtained by coating at least one of titanium (Ti), molybdenum (Mo), silver (Ag), copper (Cu), platinum (Pt), gold (Au), polyimide, and polymer on the surface of any one of Invar alloy, super Invar alloy, and stainless steel (SUS). The width × length of the movable plate may be greater than 1500 mm × 900 mm.

[0016] In the step (b), the unit sheet portion may include: an edge sheet portion; a plurality of first grid sheet portions, which are formed extending along a first direction and connected to the edge sheet portion at both ends; and a plurality of second grid sheet portions, which are formed extending along a second direction perpendicular to the first direction and intersecting with the first grid sheet portion and connected to the edge sheet portion at both ends. In the step (c), at least a portion of the edge sheet portion may be connected to the edge frame portion.

[0017] The step of applying a tensile force to the side direction of the unit sheet portion may include the following steps: (1) a suction cup provides heat to the movable plate and the metal sheet, and the suction cup is used to adsorb one side of the movable plate and move the movable plate; (2) the movable plate and the metal sheet are bonded during the process of the suction cup interrupting or reducing the heat supply.

[0018] The metal sheet can be bonded to the movable plate in a state elongated compared to its original length.

[0019] The unit sheet portion may have a quadrilateral planar shape, with a tensile force applied to all sides in a radial direction.

[0020] After the step (c), the deviation of the residual stress acting along any mask unit region may be smaller than the deviation of the residual stress acting along any mask unit region of the comparative example.

[0021] After the step (c), the residual stress value acting on the corner of any mask unit region may be smaller than the residual stress value acting on the corner of any mask unit region of the comparative example.

[0022] The difference between the maximum and minimum values ​​of the residual stress acting along any mask unit area in the comparative example can be 1.7 to 4.63 times greater than the difference between the maximum and minimum values ​​of the residual stress acting along any mask unit area after step (c).

[0023] The step (b) includes the following steps: (b1) forming a patterned first insulating portion on the second surface of the metal sheet; (b2) forming a first unit pattern of a first depth on the second surface of the metal sheet by wet etching; (b3) filling a second insulating portion in at least the first unit pattern; (b4) retaining only the second insulating portion located vertically below the first insulating portion; (b5) forming a second unit pattern of a second depth on the first unit pattern on the second surface of the metal sheet by wet etching; (b6) filling a third insulating portion in at least the second unit pattern; (b7) retaining only the third insulating portion located vertically below the second insulating portion; (b8) forming a third unit pattern of a third depth on the second unit pattern on the second surface of the metal sheet by wet etching.

[0024] In addition, the above-mentioned purpose of the present invention can be achieved through a frame, which is used in a connector between a mask and a frame for forming OLED pixels, and the frame is made by the following steps, including: (a) bonding the first side of a metal sheet to a movable plate; (b) forming a plurality of mask unit areas on the second side opposite to the first side of the metal sheet and manufacturing a unit sheet portion; (c) connecting the unit sheet portion to an edge frame portion, the edge frame portion including a hollow area, and when the process of stretching in a side direction and connecting to the edge frame portion in a state of clamping the edge of the unit sheet portion is used as a comparative example, the maximum value of the residual stress value remaining at any point on the edge of the unit sheet portion may be less than the maximum value of the residual stress value remaining at any point on the edge of the unit sheet portion of the comparative example.

[0025] The variation of the residual stress acting along any mask cell region can be smaller than the variation of the residual stress acting along any mask cell region of the comparative example.

[0026] The residual stress value acting on the corner of any mask unit region may be smaller than the residual stress value acting on the corner of any mask unit region of the comparative example.

[0027] Beneficial effects

[0028] The present invention having the above-described structure has the effect of enabling the mask to be stably supported and moved without deformation, and preventing the mask from being deformed such as sagging or twisting, thereby enabling accurate alignment.

[0029] Furthermore, the present invention has the effect of enabling accurate alignment between mask units and more clearly forming the edge portion of the frame.

[0030] Of course, the scope of the present invention is not limited by the above-mentioned effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 and 2 are a front view and a side cross-sectional view of a connection body between a mask and a frame according to an embodiment of the present invention.

[0032] Figure 2 1 is a front view and a side cross-sectional view of a frame according to an embodiment of the present invention.

[0033] Figure 3 is a schematic diagram of a mask according to an embodiment of the present invention.

[0034] Figure 4 It is a schematic diagram of the existing mask manufacturing process.

[0035] Figures 5 to 7 FIG. 1 is a schematic diagram of a mask manufacturing process according to an embodiment of the present invention.

[0036] Figure 8 FIG. 4 is a schematic diagram showing the degree of mask etching according to a comparative example of the present invention.

[0037] Figure 9 FIG. 4 is a schematic diagram of the mask etching degree according to an embodiment of the present invention.

[0038] Figure 10 FIG. 4 is a schematic diagram of adjusting the cone angle according to an embodiment of the present invention.

[0039] Figures 11 to 15 is a schematic diagram of a frame manufacturing process according to an embodiment of the present invention.

[0040] Figure 16 FIG. 1 is a schematic diagram of the stretched state of the unit sheet portion and the movable plate based on the change of process temperature according to an embodiment of the present invention.

[0041] Figures 17 and 18 FIG. 1 is a schematic diagram of a manufacturing process of a unit sheet portion according to an embodiment of the present invention.

[0042] Figure 19 FIG. 1 is a schematic diagram of a unit pattern of a unit sheet portion according to an embodiment of the present invention.

[0043] Figure 20FIG. 1 is a schematic diagram of a unit sheet portion connected to a mask according to an embodiment of the present invention.

[0044] Figure 21 FIG. 1 is an electron microscope photograph of a unit pattern according to an embodiment of the present invention.

[0045] Figure 22 FIG. 1 is a schematic diagram showing an alignment state of a mask cell region of a unit sheet portion according to a comparative example.

[0046] Figure 23 Based on the comparative example Figure 22 Schematic diagram of the edge position values ​​of each mask unit area.

[0047] Figure 24 is a schematic diagram of a process of connecting a unit sheet portion to an edge frame portion according to a comparative example.

[0048] Figure 25 Graphs showing the tensile forces measured when tensile forces are applied outward at various points of the unit sheet portion connected to the edge frame portion according to a comparative example and an embodiment of the present invention. Figure 26 yes Figure 25 Enlarged view of the data portion marked in .

[0049] [Description of Reference Numerals]

[0050] 10: Connector between mask and frame

[0051] 80: Suction Cup

[0052] 90: Mobile board

[0053] 95: Temporary adhesive part, dry film resist layer

[0054] 100: Mask

[0055] 110: Mask film, metal sheet

[0056] 200: Framework

[0057] 210: Edge frame

[0058] 220: Unit sheet

[0059] 220': Metal sheet for manufacturing unit sheet

[0060] 221: Edge sheet part

[0061] 223: First grid sheet portion

[0062] 225: Second grid sheet portion

[0063] 1000: OLED pixel deposition device

[0064] C: unit, mask unit

[0065] Ca, Cb, Cc: first unit pattern, second unit pattern, third unit pattern

[0066] CP: Cell Pattern

[0067] CR: Mask cell region

[0068] Ma, Mb, Mc: first insulating part

[0069] R: Hollow area of ​​edge frame

[0070] P: mask pattern

[0071] P1, P1-1, P1-2: first mask pattern

[0072] P2, P2-1, P2-2: second mask pattern DETAILED DESCRIPTION

[0073] For the detailed description of the present invention described below, reference may be made to the accompanying drawings which illustrate specific embodiments in which the present invention may be implemented. In order to enable those skilled in the art to implement the present invention, these embodiments are described in detail below. These embodiments are described in sufficient detail so that a person with ordinary knowledge in the art can implement the present invention. The various embodiments of the present invention should be understood to be different from each other but not mutually exclusive. For example, the specific shapes, structures and characteristics described herein can be implemented as other embodiments of one embodiment without exceeding the spirit and scope of the present invention. In addition, the position or arrangement of the individual components in each disclosed embodiment should be understood to be subject to change without exceeding the spirit and scope of the present invention. Therefore, the following detailed description is not intended to limit the present invention. As long as it can be properly described, the scope of the present invention is limited only by the appended claims and all equivalents thereof. Similar figure numbers in the drawings refer to the same or similar functions in various aspects. For convenience, length, area, thickness, etc. and their forms may also be exaggerated.

[0074] Hereinafter, in order to enable those skilled in the art to easily implement the present invention, preferred embodiments according to the present invention are described in detail with reference to the accompanying drawings.

[0075] Figure 1 This is a front view of a frame-integrated mask according to an embodiment of the present invention. Figure 1 (a)] and side cross-sectional view [ Figure 1 (b)]. Figure 2 is a main view of a frame according to an embodiment of the present invention. Figure 2 (a)] and side cross-sectional view [ Figure 2 (b)].

[0076] Below, although this specification describes the structure of the mask and frame connection body (or frame-integrated mask), the structure and manufacturing process of the mask and frame connection body can be understood as including the entire content of Korean Patent Application No. 2018-0016186.

[0077] Reference Figure 1 as well as Figure 2 The mask-frame connector 10 (or frame-integrated mask) can include multiple masks 100 and a frame 200. In other words, multiple masks 100 are individually connected to the frame 200. Below, for ease of explanation, a square mask 100 is used as an example. However, before the mask 100 is attached to the frame 200, it can be a strip-shaped mask with protrusions on both sides for clamping. After attachment to the frame 200, the protrusions can be removed.

[0078] A plurality of mask patterns P are formed on each mask 100, and one cell C may be formed on one mask 100. One mask cell C may correspond to one display of a smartphone or the like.

[0079] The mask 100 may also be made of materials such as invar, superinvar, nickel (Ni), nickel-cobalt (Ni-Co), etc. The mask 100 may be made of a metal sheet produced by rolling or electroforming.

[0080] The frame 200 can be formed to connect multiple masks 100. Considering thermal deformation, the frame 200 is preferably formed from a material such as Invar, Super Invar, nickel, or nickel-cobalt, which has a thermal expansion coefficient equal to that of the masks. The frame 200 can include a roughly quadrangular or square edge frame portion 210. The interior of the edge frame portion 210 can be hollow.

[0081] In addition, the frame 200 has a plurality of mask unit regions CR and may include a unit sheet portion 220 connected to the edge frame portion 210. The unit sheet portion 220 may be composed of an edge sheet portion 221, a first grid sheet portion 223, and a second grid sheet portion 225. The edge sheet portion 221, the first grid sheet portion 223, and the second grid sheet portion 225 are sections divided on the same sheet and are integrally formed with each other.

[0082] The thickness of the edge frame portion 210 can be greater than that of the unit sheet portion 220, and can be formed with a thickness of several millimeters to several centimeters. Although thinner than the edge frame portion 210, the unit sheet portion 220 is thicker than the mask 100, and can be approximately 0.1 mm to 1 mm. The width of the first grid sheet portion 223 and the second grid sheet portion 225 can be approximately 1-5 mm.

[0083] In addition to the areas occupied by the edge sheet portion 221, the first grid sheet portion 223, and the second grid sheet portion 225, a plurality of mask unit regions CR (CR11-CR56) can be provided in the planar sheet. This specification uses the example of forming a 6×5 mask unit region CR (CR11-CR56). There can be five first grid sheet portions 223 and four second grid sheet portions 225.

[0084] The frame 200 has multiple mask cell regions CR, and each mask 100 can be attached so that each mask cell C corresponds to each mask cell region CR. The mask cells C correspond to the mask cell regions CR of the frame 200, and part or all of the dummy portion can be attached to the frame 200 (cell sheet portion 220). Thus, the mask 100 and frame 200 can form an integrated structure.

[0085] The specific manufacturing process of the frame 200 will be described in detail in Figures 11 to 15 The process of forming the mask unit region CR of the unit sheet portion 220 will be described in Figure 17 Described in.

[0086] Figure 3 is a schematic diagram of a mask 100 according to an embodiment of the present invention.

[0087] Each mask 100 may include a mask cell C formed with a plurality of mask patterns P and a dummy portion (equivalent to the portion of the mask film 110 excluding the cell C) surrounding the mask cell C. The dummy portion may comprise only the mask film 110, or may comprise the mask film 110 formed with a predetermined dummy portion pattern having a similar form to the mask pattern P. The mask cell C corresponds to the mask cell region CR of the frame 200, and part or all of the dummy portion may be attached to the frame 200 (cell sheet portion 220). Thus, the mask 100 and the frame 200 may form an integrated structure.

[0088] On the other hand, according to another embodiment, the frame is not manufactured by attaching the unit sheet portion 220 to the edge frame portion 210. Instead, a grid frame (equivalent to the grid sheet portions 223 and 225) can be directly formed in the hollow region R of the edge frame portion 210 to be integrated with the edge frame portion 210. This type of frame also includes at least one mask unit region CR, and the mask 100 can be aligned with the mask unit region CR to manufacture the mask-frame connection body 10.

[0089] Next, a process of manufacturing the mask 100 will be described.

[0090] Figure 4 It is a schematic diagram of the existing mask manufacturing process.

[0091] Reference Figure 4 , the existing mask manufacturing process only performs wet etching.

[0092] First, if Figure 4 As shown in (a), a patterned photoresist M may be formed on the planar film 110' (sheet). Then, as shown in Figure 4 (b) Wet etching WE can be performed through the spaces between the patterned photoresist M. After wet etching WE, some of the spaces between the film 110' are penetrated, thereby forming a mask pattern P'. Then, if the photoresist M is cleaned, the film 110' having the mask pattern P' formed thereon is completed, thereby completing the manufacture of the mask 100'.

[0093] like Figure 4 As shown in (b), the existing mask 100' has the problem of non-constant size of the mask pattern P'. Since the wet etching WE is performed isotropically, the shape after etching is roughly arc-shaped. Moreover, since it is difficult to keep the etching speed of each part consistent during the wet etching WE process, the widths R1', R1", and R1"' of the through pattern after penetrating the film 110' are different. In particular, in patterns where undercuts UC occur more frequently, not only the lower width R1" but also the upper width R2" of the mask pattern P' will be wider, while in patterns where undercuts UC occur less frequently, the lower widths R1', R1"' and the upper widths R2', R2"' are relatively narrow.

[0094] As a result, the existing mask 100' suffers from uneven dimensions of each mask pattern P'. For ultra-high-definition OLEDs, current QHD resolution is 500-600 PPI (pixels per inch), with pixel sizes reaching approximately 30-50 μm. 4K UHD and 8K UHD resolutions reach even higher resolutions, such as -860 PPI and -1600 PPI. Therefore, even slight dimensional differences can lead to product defects.

[0095] Therefore, a feature of the present invention is to improve the pattern accuracy of the insulating mask during the wet etching process by performing wet etching twice.

[0096] Figures 5 to 7 FIG. 1 is a schematic diagram of a mask manufacturing process according to an embodiment of the present invention.

[0097] Reference Figure 5 In step (a), a metal sheet 110 for mask manufacturing may be provided. As described above, the material of the metal sheet 110 may be invar, superinvar, nickel (Ni), nickel-cobalt (Ni-Co), or the like.

[0098] Then, a patterned first insulating portion M1 may be formed on one side (upper side) of the metal sheet 110. The first insulating portion M1 may be formed of a photoresist material by a printing method or the like.

[0099] The first insulating portion M1 may be a black matrix photoresist or a photoresist material with a metal coating formed on the top. The black matrix photoresist may be a material comprising a black matrix resin (resin black matrix), which is used to form the black matrix of the display panel. The black matrix photoresist has a better light-shielding effect than a general photoresist. In addition, the photoresist with a metal coating formed on the top can enhance the light-shielding effect of light irradiated from above by the metal coating liquid.

[0100] Then, refer to Figure 5 In step (b), a first mask pattern P1 having a predetermined depth can be formed on one side (the upper side) of the metal sheet 110 by wet etching WE1. When wet etching WE1 is performed, the first mask pattern P should not penetrate the metal sheet 110. Therefore, the first mask pattern P can be formed generally in an arc shape and not penetrate the metal sheet 110. In other words, the depth of the first mask pattern P1 can be less than the thickness of the metal sheet 110.

[0101] Because the wet etching process WE1 has isotropic etching characteristics, the width R2 of the first mask pattern P1 differs from the spacing R3 between patterns in the first insulating portion M1 and can be wider than the spacing R3 between patterns in the first insulating portion M1. In other words, because undercuts UC are formed below both sides of the first insulating portion M1, the width R2 of the first mask pattern P1 can be wider than the spacing R3 between patterns in the first insulating portion M1 by a width sufficient to form the undercuts UC.

[0102] Then, refer to Figure 5(c) A second insulating portion M2 can be formed on one side (top) of the metal sheet 110. The second insulating portion M2 can be formed from a photoresist material by printing or the like. Since the second insulating portion M2 needs to be retained in the space for forming the undercut UC described later, a positive photoresist material is preferably used.

[0103] Since the second insulating portion M2 is formed on one side (upper side) of the metal sheet 110 , a portion of the second insulating portion M2 is formed on the first insulating portion M1 , and the other portion is filled inside the first mask pattern P1 .

[0104] The second insulating portion M2 can be made of a photoresist diluted in a solvent. If a high-concentration photoresist solution is formed on the metal sheet 110 and the first insulating portion M1, it will react with the photoresist in the first insulating portion M1, potentially dissolving a portion of the first insulating portion M1. Therefore, to minimize the effect on the first insulating portion M1, the second insulating portion M2 can be made of a photoresist with a reduced concentration after dilution in a solvent.

[0105] Then, refer to Figure 6 (d) The second insulating portion M2 can be partially volatilized by baking. After the solvent in the second insulating portion M2 is volatilized by baking, only the photoresist component remains. As a result, a thin portion of the second insulating portion M2' remains in the exposed portion of the first mask pattern P1 and on the surface of the first insulating portion M1, resembling a coated film. The remaining second insulating portion M2' is preferably less than a few μm thick, so as not to affect the pattern width R3 of the first insulating portion M1 or the pattern width R2 of the first mask pattern P1.

[0106] Then, refer to Figure 6 (e) can be exposed on one side (top) of the metal sheet 110. When the exposure L is performed above the first insulating portion M1, the first insulating portion M1 can act as an exposure mask. Since the first insulating portion M1 is a black matrix photoresist or a photoresist material with a metal coating formed on the upper portion, it has an excellent light shielding effect. Therefore, the second insulating portion M2 "[refer to Figure 6 (f)] will not be exposed to L, while the other insulating portion M2' will be exposed to L.

[0107] Then, refer to Figure 6(f), if the exposure L is followed by development, the portion of the second insulating portion M2' which is not exposed to the exposure L will remain, while the other second insulating portions M2' will be removed. Since the second insulating portion M2' is a positive photoresist, the portion exposed to the exposure L will be removed. The space left for the second insulating portion M2' can form an undercut UC below both sides of the first insulating portion M1 [refer to Figure 5 (b) step] corresponds to the space.

[0108] Then, refer to Figure 7 (g) Wet etching WE2 can be performed on the first mask pattern P1 of the metal sheet 110. The wet etching liquid penetrates the spaces between the patterns of the first insulating portion M1 and the spaces of the first mask pattern P1, and wet etching WE2 is performed. The second mask pattern P2 can be formed through the metal sheet 110. In other words, it is formed by penetrating from the lower end of the first mask pattern P1 to the other side of the metal sheet 110.

[0109] At this time, a second insulating portion M2" is left on the first mask pattern P1. The remaining second insulating portion M2" can act as a mask for wet etching. That is, the second insulating portion M2" masks the etching liquid and prevents the etching liquid from etching toward the side of the first mask pattern P1, and etches toward the lower surface of the first mask pattern P1.

[0110] Since the second insulating portion M2" is arranged in the undercut UC space vertically below the first insulating portion M1, the pattern width of the second insulating portion M2" substantially corresponds to the pattern width R3 of the first insulating portion M1. Therefore, the second mask pattern P2 is equivalent to wet etching WE2 on the spacing R3 between the patterns of the first insulating portion M1. Therefore, the width R1 of the second mask pattern P2 can be smaller than the width R2 of the first mask pattern P1.

[0111] Because the width of the second mask pattern P2 defines the width of the pixel, its width is preferably less than 35 μm. If the second mask pattern P2 is too thick, it becomes difficult to control its width R1, and the uniformity of width R1 decreases, potentially resulting in the mask pattern P not having an overall tapered / inverted tapered shape. Therefore, the thickness of the second mask pattern P2 is preferably less than that of the first mask pattern P1. The thickness of the second mask pattern P2 is preferably close to zero. Considering the pixel size, for example, the thickness of the second mask pattern P2 is preferably approximately 0.5 to 3.0 μm, more preferably 0.5 to 2.0 μm.

[0112] The mask pattern P is formed by combining the connected first mask pattern P1 and the second mask pattern P2 .

[0113] Then, refer to Figure 7(h) The mask 100 can be manufactured by removing the first insulating portion M1 and the second insulating portion M2. The first mask pattern P1 includes an inclined surface, and the height of the second mask pattern P2 is very low. Therefore, if the shapes of the first mask pattern P1 and the second mask pattern P2 are combined, the overall shape is tapered or inverted tapered.

[0114] Figure 8 FIG. 4 is a schematic diagram showing the degree of mask etching according to a comparative example of the present invention.

[0115] Reference Figure 8 , since the wet etching WE is performed isotropically, the shape after etching is roughly in the shape of a circular arc. Moreover, during the wet etching process, it is difficult for the etching speeds of each part to be exactly the same. If only one wet etching is performed to penetrate the metal sheet 110 to form the mask pattern, the deviation will be greater. For example, although the wet etching speeds of the mask pattern 111 and the mask pattern 112 are different, the difference in the upper width (bottom cut) is not very large. However, the difference between the lower penetration width PD1 of the metal sheet 110 caused by the formation of the mask pattern 111 and the lower penetration width PD2 of the metal sheet 110 caused by the formation of the mask pattern 112 is much larger than the upper width difference. This is a result of the isotropic wet etching. In other words, it is the lower widths PD1 and PD2 of the mask patterns 111 and 112, rather than the upper width, that determine the width of the pixel size. Therefore, compared to one wet etching, it is easier to control the lower widths PD1 and PD2 if two wet etchings are performed. Below, Figure 9 The present invention will be further described by taking an embodiment of the present invention as an example.

[0116] Figure 9 FIG. 4 is a schematic diagram of the mask etching degree according to an embodiment of the present invention.

[0117] Figure 9 The process up to (a) Figure 5 The process is the same as described in (a) to (b) of Figure 9 In (a), the first mask pattern P1-1 and the first mask pattern P1-2 showing different etching degrees in the wet etching WE1 of the first insulating portion M1 are compared and described.

[0118] Reference Figure 9 In (a), even with the same wet etching process WE1-1 and WE1-2, different etching degrees can occur depending on the etched portion, as shown in the first mask pattern P1-1 and the first mask pattern P1-2. The pattern width R2-1 of the first mask pattern P1-1 is smaller than the pattern width R2-2 of the first mask pattern P1-2. This difference in pattern widths R2-1 and R2-2 can adversely affect pixel resolution.

[0119] Then, refer to Figure 9 (b), it can be confirmed that when executing Figure 5 (c) to Figure 6 After the process described in (f), the second insulating parts M2"-1 and M2"-2 are respectively formed in the space vertically below the first insulating part M1. Depending on the size of the undercut space below the first insulating part, the sizes of the second insulating parts M2"-1 and M2"-2 will be different. Although the size of the second insulating part M2"-1 is smaller than the size of the second insulating part M2"-2, the pattern widths of the second insulating parts M2"-1 and M2"-2 will be equal. The pattern widths of the second insulating parts M2"-1 and M2"-2 can be equal to correspond to the pattern width R3 of the first insulating part M1.

[0120] Then, refer to Figure 9 (c) The second insulating portions M2″-1 and M2″-2 are respectively used as masks for wet etching and a second wet etching WE2 is performed, thereby penetrating the metal sheet 110. As a result, the deviations of the widths R1-1 and R1-2 of the formed second mask patterns P2-1 and P2-2 are significantly smaller than the deviations of the widths R2-1 and R2-2 of the first mask patterns P1-1 and P1-2. This is because, after the metal sheet 110 is first wet-etched at the depth of the first mask patterns P1-1 and P1-2, and then the remaining thickness of the metal sheet 110 is wet-etched for a second time, the pattern widths of the second insulating portions M2″-1 and M2″-2 subjected to the second wet etching are substantially equal to the pattern widths of the first insulating portion M1 subjected to the first wet etching.

[0121] As described above, the mask manufacturing method of the present invention can effectively form a mask pattern P with the desired dimensions by performing two wet etching steps. In particular, since a portion of the second insulating portion M2″ is left, the second wet etching step allows the second mask pattern P2 to be etched narrower and thinner than the first wet etching step, thereby making it easier to control the width R1 of the second mask pattern P2. Furthermore, since the wet etching step can form an inclined surface, it is possible to form a mask pattern P that prevents shadowing.

[0122] Figure 10 FIG. 1 is a schematic diagram of adjusting the cone angles a1 and a2 according to an embodiment of the present invention.

[0123] In addition, the mask manufacturing method of the present invention has the advantage that the mask pattern P composed of the first mask pattern P1 and the second mask pattern P2 is easy to form a tapered angle. Moreover, the present invention has the effect of easily adjusting the tapered angles a1 and a2. Figure 10(a), if the thickness T1 of the second mask pattern P2 is thinner, the taper angle a1 will become larger. In other words, if the thickness of the first mask pattern P1 is thick and the thickness T1 of the second mask pattern P2 is thinner, the taper angle a1 will become larger as a result of isotropic wet etching (R1 is the radius). On the contrary, referring to Figure 10 (b), if the thickness T2 of the second mask pattern P2 becomes thicker, the taper angle a2 will become smaller. In other words, compared to Figure 10 In (a), if the thickness of the first mask pattern P1 is thin and the thickness T2 of the second mask pattern P2 is thicker, the tapered angle a2 will increase as a result of isotropic wet etching (R1 is the radius). Therefore, the present invention has the advantage of being able to adjust the tapered angles a1 and a2 by adjusting the thickness of the second mask pattern P2.

[0124] Hereinafter, the manufacturing process of the mask and frame connection body 10 of the present invention will be further described.

[0125] Figures 11 to 15 is a schematic diagram of a frame manufacturing process according to an embodiment of the present invention.

[0126] To manufacture a connected body of the mask 100 and the frame 200 (or a frame-integrated mask), the frame 200 may be provided. First, the unit sheet portion 220 is manufactured and then the frame 200 is manufactured by connecting the unit sheet portion 220 to the edge frame portion 210. Alternatively, the unit sheet portion 220 may be manufactured and then connected to the edge frame portion 210 after the edge frame portion 210 is prepared.

[0127] Reference Figure 11 , a metal sheet 220' for manufacturing the unit sheet portion 220 of the frame 200 can be prepared. The material of the metal sheet 220' is similar to the metal sheet 110 for mask manufacturing [refer to Figure 5 (a)], it can be invar, superinvar, nickel (Ni), nickel-cobalt (Ni-Co), etc.

[0128] The metal sheet 220' is used as the unit sheet portion 220 for supporting the mask 100 and may be thicker than the mask 100. The thickness of the metal sheet 220' may be greater than that of the mask 100 and be approximately 70 μm to 200 μm.

[0129] In addition, a movable plate 90 may be provided. The movable plate 90 is a medium that can adhere to the first surface (lower surface) of the metal sheet 220' and support it while moving. To fully support the metal sheet 220', the movable plate 90 is a flat plate with an area greater than or equal to that of the metal sheet 220'.

[0130] As an example, the width×length of 6G can be about 1500mm×1800mm, and half of 6G can be about 1500mm×900mm. Figure 1 The size of the plurality of masks 100 excluding the edge frame portion 210 and the unit sheet portion 220 to which the plurality of masks 100 are attached can be half the size of the 6G. In view of this, the size of the movable plate 90 for supporting the unit sheet portion 220 is preferably about 1500 mm in width × 900 mm in length or more.

[0131] The movable plate 90 may be made of a material that is transparent to the laser light L. Examples of materials that may be used include glass, silica, quartz, alumina (Al 2 O 3 ), borosilicate glass, zirconia, and silicate ceramics.

[0132] According to one embodiment, the movable plate 90 has a large area corresponding to half of the 6G, and is preferably made of a glass material that is easy to form, easy to process, and low in cost, and more preferably a silicate glass or borosilicate glass material. In particular, borosilicate glass having excellent heat resistance, chemical resistance, mechanical strength, transparency, etc. can be used. 33 materials. In addition, The thermal expansion coefficient of 33 is about 3.3, which is not much different from the thermal expansion coefficient of the Invar alloy metal sheet 220 ′, and has the advantage of being easy to control the metal sheet 220 ′.

[0133] According to another embodiment, the movable plate 90 may be made of materials such as titanium (Ti), molybdenum (Mo), silver (Ag), copper (Cu), platinum (Pt), and gold (Au), which are resistant to etching solutions such as F2Cl3.

[0134] According to another embodiment, movable plate 90 can be made of Invar, Super Invar, or stainless steel (SUS) coated with the aforementioned corrosion-resistant metals, such as Ti, Mo, Ag, Cu, Pt, and Au, or coated with polyimide or a polymer such as plastic. Furthermore, polyimide or a hard polymer such as plastic can be used directly as movable plate 90. This advantageously allows movable plate 90 to be easily formed into the aforementioned half-6G or 6G sizes.

[0135] A temporary adhesive portion 95 may be provided between the movable plate 90 and the metal sheet 220'. The temporary adhesive portion 95 may be a device that provides an adhesive force for bonding the metal sheet 220' to the movable plate 90. In particular, a dry film resist layer 95 (DFR layer) may be provided as the temporary adhesive portion 95. A thin film of photoresist may be provided as the dry film resist layer 95. As an example, a soft bake (baking) may be performed at a temperature of approximately 60°C for 60 seconds and a lamination process may be performed directly. While peeling off the protective film of the DFR, the photoresist layer of the DFR may be laminated on the first surface (lower surface) of the metal sheet 220'. Lamination may be performed with a predetermined roller pressure and a low-temperature process below approximately 60°C. Lamination is preferably performed under a vacuum state. Lamination under a vacuum state can prevent bubbles from being trapped at the interface between the dry film resist layer 95 and the metal sheet 220' / movable plate 90.

[0136] The present invention utilizes a dry film resist layer 95 to perform bonding and photolithography processes at low temperatures below approximately 60°C, thereby preventing heat-induced deformation of the metal sheet 200' during the process steps. Furthermore, the use of dry film resist 95 significantly reduces baking and exposure times compared to liquid photoresist. While the degassing baking and exposure process with liquid photoresist takes approximately one hour, using dry film resist only requires approximately two minutes, significantly reducing process time.

[0137] According to Korean Patent Application No. 2020-0043485 Figure 11 The prior art uses liquid wax to bond the mask metal film to the substrate for supporting the mask metal film. The liquid wax layer is baked at a temperature of about 100 to 160°C in order to vaporize the solvent during use, and the lamination process is also carried out at a temperature of about 110°C. Therefore, in the high temperature range above 100°C, the mask metal film or metal sheet may have the problem of thermal deformation. In addition, liquid wax is also used in addition to liquid photoresist to form the etching pattern. That is, in the prior art, a liquid wax layer and a liquid photoresist layer are used between the mask metal film and the substrate for supporting the mask metal film.

[0138] In contrast, the present invention utilizes a dry film resist layer 95, enabling bonding processes at temperatures below approximately 60°C. Furthermore, the dry film resist layer 95 alone achieves both bonding and etching pattern formation, eliminating the need for separate layers of liquid wax and liquid photoresist. Furthermore, as will be described later, the dry film resist layer 95 even provides corrosion resistance and adhesion to the metal sheet 220' during the formation of the third unit pattern Cc.

[0139] in addition, Figure 11 Although not shown, it can also be found in Figure 11 The steps will be as follows Figure 14 The components such as the suction cup 80 shown in FIG. 8 are adsorbed on the moving plate 90 to control the movement of the moving plate 90 .

[0140] Then, refer to Figure 12 , a patterned insulating portion MM may be formed on the metal sheet 220 ′. The insulating portion MM may be formed of a photoresist material using a printing method or the like.

[0141] Next, the metal sheet 220' can be etched EC. Etching can be performed using dry etching, wet etching, or other methods, without particular limitation. As a result, the exposed portion of the metal sheet 220' between the insulating portions MM is etched. The etched portion of the metal sheet 220' can be sized to the size of the mask unit region CR, the size of the mask 100, or the size of the display on which the OLED pixel is formed.

[0142] Then, refer to Figure 13 , the insulating portion MM can be removed. After etching EC, the metal sheet 220' can be a metal sheet portion 220 formed with an edge sheet portion 221, a first grid sheet portion 223, and a second grid sheet portion 225. The movable plate 90 can be provided in a form in which the unit sheet portion 220 is bonded thereto with a temporary bonding portion 95 (or dry film resist layer 95) interposed therebetween. The unit sheet portion 220 is formed with an edge sheet portion 221, a first grid sheet portion 223, and a second grid sheet portion 225.

[0143] Then, refer to Figure 14 The movable plate 90, to which the unit sheet portion 220 is bonded and supported, can be loaded onto the edge frame portion 210. The movable plate 90 can be transferred by a vacuum suction cup (not shown). For example, the movable plate 90 can be transferred by suctioning the surface opposite to the surface to which the unit sheet portion 220 is bonded using the vacuum suction cup 80.

[0144] The unit sheet portion 220 can contact and correspond to the edge frame portion 210. That is, the edge sheet portion 221 of the unit sheet portion 220 can contact and correspond to the upper surface of the edge frame portion 210. By loading the movable plate 90 onto the edge frame portion 210, the unit sheet portion 220 can be aligned with the edge frame portion 210. Since the movable plate 90 presses the unit sheet portion 220, the unit sheet portion 220 and the edge frame portion 210 can be closely abutted.

[0145] Next, laser light L is irradiated between the unit sheet portion 220 (or the edge sheet portion 221) and the edge frame portion 210, and the unit sheet portion 220 can be connected to the edge frame portion 210 by laser welding. A weld bead WB is generated between the laser-welded edge sheet portion 221 and the edge frame portion 210, and the edge sheet portion 220 can be connected to the edge frame portion 210 through the weld bead WB.

[0146] Then, refer to Figure 15 After the unit sheet portion 220 and the edge frame portion 210 are connected, the movable plate 90 can be separated (debonded) from the unit sheet portion 220. The unit sheet portion 220 and the movable plate 90 can be separated by heating, chemically treating, applying ultrasound, or applying UV to the temporary adhesive portion 95 [or the dry film resist layer 95]. By heating, chemically treating, applying ultrasound, or applying UV to the temporary adhesive portion 95, the bonding force between the unit sheet portion 220 and the movable plate 90 is weakened, thereby separating the movable plate 90 from the unit sheet portion 220. After separating the movable plate 90, the temporary adhesive portion 95 remaining in the unit sheet portion 220 can be removed by cleaning or other methods.

[0147] Therefore, if Figure 15 (a) [side cross-sectional view], Figure 15 As shown in (b) [front view] of FIG, the unit sheet portion 220 is connected to the edge frame portion 210 . This can be provided as the frame 200 .

[0148] According to another embodiment, the edge sheet portion 221 and the edge frame portion 210 may be connected by metal connecting portions instead of laser welding. Figure 14 As shown, the movable plate 90, to which the unit sheet portion 220 is bonded and supported, can be loaded onto the edge frame portion 210. In this case, a metal connection portion (not shown) can be interposed between the unit sheet portion 220 (or the edge sheet portion 221) and the edge frame portion 210. The metal connection portion (not shown) can be formed on the lower surface of the edge sheet portion 221 facing the edge frame portion 210. Alternatively, the metal connection portion (not shown) can be formed on the upper surface of the edge frame portion 210 facing the edge sheet portion 221.

[0149] The metal connection portion may include at least one material selected from the group consisting of Cu, Ni, Au, Ag, Al, Sn, In, Bi, Zn, Sb, Ge, and Cd. The metal connection portion is preferably formed by sputtering or soldering, which are not limited to any material and can easily form a thin film.

[0150] Next, at least one of heat and pressure may be applied to the metal connection portion. The unit sheet portion 220 and the metal connection portion, i.e., the edge frame portion 210, may be heated to perform a heat treatment. Alternatively, by simultaneously heating the unit sheet portion 220, the metal connection portion, and the edge frame portion 210 while applying pressure, a heat treatment can be performed with minimal heat.

[0151] The heat treatment by applying heat and pressure can be performed within the range where the metal connection portion can connect the unit sheet portion 220 and the edge frame portion 210. As an example, the metal of the metal connection portion can be melted during the heat treatment and then resolidified to connect the unit sheet portion 220 and the edge frame portion 210. As another example, the interface state of the unit sheet portion 220 and the edge frame portion 210 can be changed and connected by the diffusion of metal components of the metal connection portion into the unit sheet portion 220 and the edge frame portion 210, or conversely, by the diffusion of components of the unit sheet portion 220 and the edge frame portion 210 into the metal connection portion, or by mutual diffusion of components.

[0152] The heat treatment may be performed at a temperature of about 200°C to 800°C, and more preferably, at a low temperature range of about 200°C to 400°C.

[0153] After the unit sheet portion 220 and the edge frame portion 210 are connected, the movable plate 90 may be separated from the unit sheet portion 220. The above-described separation process of the movable plate 90 may be directly employed.

[0154] Figure 16 FIG. 1 is a schematic diagram of the stretched state of the unit sheet portion and the movable plate based on the change of process temperature according to an embodiment of the present invention.

[0155] In the prior art, when aligning the unit sheet portion 220 with the edge frame portion 210, all sides of the unit sheet portion 220 are first stretched to flatten the unit sheet portion 220, and then the edge sheet portion 221 is aligned with the edge frame portion 210. Next, the edge sheet portion 221 is connected to the edge frame portion 210. Furthermore, after the planar sheet is stretched and attached to the edge frame portion 210, the mask unit regions CR can be removed by laser scribing, etching, or the like, to form the unit sheet portion 220. However, because the conventional method directly stretches the side surfaces of the unit sheet portion 220 by connecting a clamping device such as a jig, there is a problem of increased alignment error between the mask unit regions CR.

[0156] On the contrary, the present invention forms the mask unit area CR in a state where the metal sheet 220' is bonded and supported on the movable plate 90, without stretching the manufactured unit sheet portion 220. The supporting unit sheet portion 220 is connected to the edge frame portion 210 in a state where it is bonded and supported by the movable plate 90, thereby having the effect of reducing alignment errors.

[0157] The present invention does not use a clamping device such as a clamp directly connected to the side of the unit sheet portion 220 to perform stretching. Instead, it utilizes the difference in thermal expansion coefficient between the movable plate 90 and the metal sheet 220' to control the temperature and apply internal tensile force to the metal sheet 220' on the movable plate 90. The large-area metal sheet 220' can apply uniform tensile force in all directions or along the radial direction on the large-area movable plate 90. Figure 16 The operation of the metal sheet 220 ′ in the process of contacting the moving plate 90 will be described.

[0158] According to one embodiment, Figure 16 As shown, the degree of stretching or the stretching force IT of the metal sheet 220 ′ can be controlled by controlling the process temperature. Figure 16 In (a), in order to compare the extent of expansion and contraction of the metal sheet 220 ′ and the movable plate 90 , the initial lengths are the same, but the movable plate 90 may be greater than or equal to the length of the metal sheet 220 ′, and vice versa.

[0159] Reference Figure 16 (a) A movable plate 90 and a metal sheet 220 ′ (or a unit sheet portion 220 having a mask unit region CR formed thereon) are prepared at a room temperature RT (Room Temperature) of approximately 25° C. Figure 16Taking the example of metal sheet 220' being made of Invar and movable plate 90 being made of quartz, which has a lower thermal expansion coefficient than Invar, as an example, temporary adhesive portion 95 (or dry film resist 95) may be formed on one side of movable plate 90 or / and metal sheet 220'.

[0160] Next, refer to Figure 16 (b) The process temperature can be raised to a level where the push-pull strength of the temporary adhesive portion 95 becomes 0 to 5 kgf / cm 2 The first process temperature TS1 may be about 50 to 70° C. At the first process temperature TS1, the temporary adhesive portion 95 may be 0 to 5 kgf / cm 2 , it is as if the temporary adhesive portion 95 does not have the adhesive force for bonding the metal sheet 220' and the movable plate 90. That is, the temporary adhesive portion 95 is in a non-sticky state, that is, the metal sheet 220' and the movable plate 90 are not easily bonded. It can be understood that the metal sheet 220' can be easily separated from the movable plate 90 even without load or external force. As a result, the metal sheet 220' and the movable plate 90 are only in a state of contact with each other with the temporary adhesive portion 95 [and the first insulating portion 23] sandwiched between them, and are not bonded. The metal sheet 220' can be linearly stretched as the temperature rises without being hindered by the temporary adhesive portion 95. Moreover, the thermal expansion coefficient of the movable plate 90 is lower than the thermal expansion coefficient of the metal sheet 220'. Therefore, at the first process temperature TS1, the stretching degree L1 of the metal sheet 220' can be greater than the stretching degree L2 of the movable plate 90.

[0161] Next, refer to Figure 16 (c), with the metal sheet 220' in contact with the movable plate 90, the process temperature can be lowered to a level where the bonding strength of the temporary bonding portion 95 is at least greater than 5 kgf / cm 2 The second process temperature TS2 is approximately 40 to 60°C lower than the first process temperature TS1 and may be higher than room temperature. At the second process temperature TS2, the temporary adhesive portion 95 exhibits adhesive strength, allowing the metal sheet 220' to bond to the movable plate 90. As the temperature decreases, the movable plate 90 contracts (L2 -> L3), and the metal sheet 220' also contracts accordingly.

[0162] However, the process temperature Figure 16When the process from step (b) to step (c) is decreased (TS1->TS2), the temporary bonding portion 95 cools and hardens first, while the temperature of the metal sheet 220' decreases at a slower rate than that of the temporary bonding portion 95. As a result, the metal sheet 220' can be bonded to the movable plate 90 in a stretched state. In other words, compared to directly increasing the temperature to the second process temperature TS2 at room temperature RT and then bonding the metal sheet 220' to the movable plate 90, Figure 16 As shown, by adding a step of increasing the temperature to the first process temperature TS1 between room temperature RT and the second process temperature TS2, the metal sheet 220' can be bonded to the movable plate 90 in a further stretched state. After directly increasing the temperature from room temperature RT to the second process temperature TS2, when the metal sheet 220' is bonded to the movable plate 90, the temporary bonding portion 95 has a considerable adhesive force. Therefore, the metal sheet 220' is hindered by the temporary bonding portion 95 and may not experience linear stretching as the temperature rises. The further stretching of the metal sheet 220' corresponds to a further increase in the tensile force IT contained in the metal sheet 220' supported on the movable plate 90, which means that after the unit sheet portion 220 is aligned with / attached to the edge frame portion 210 in the subsequent process, the unit sheet portion 220 may be in a further expanded state.

[0163] However, it should be noted that this does not exclude the process of directly raising the temperature from room temperature RT to the second process temperature TS2 and then bonding the metal sheet 220 ′ to the movable plate 90 .

[0164] Next, refer to Figure 16 (e) The process temperature can be raised to room temperature RT. As the temperature drops, the movable plate 90 can shrink (equivalent to L3), and the metal sheet 220' also shrinks accordingly. The movable plate 90 can be restored to Figure 16 The length of the metal sheet 220' in the initial state at room temperature (RT) is obtained by bonding and fixing the metal sheet 220' to the movable plate 90 in a state stretched by L5 compared to the initial state at room temperature (RT). The degree of stretching L5 and the tensile force IT contained in the metal sheet 220' are greater than those in the process of bonding the metal sheet 220' to the movable plate 90 after directly raising the temperature from room temperature (RT) to the second process temperature TS2.

[0165] In addition, Figure 16 Between steps (c) and (e), a process of lowering the process temperature to a process temperature TS3 lower than the room temperature RT may be performed. Then, the temperature may be raised back to the room temperature RT. As the temperature drops to the process temperature TS3, the movable plate 90 further contracts by L4 compared to the room temperature state, and the metal sheet 220' may contract accordingly. The process temperature TS3 may be approximately 5 to 15°C. Moreover, the maintenance time of the process temperature TS3 may be at least equal to or greater than Figure 16The maintenance time of process temperature TS1 and TS2 of (b) and (c) is determined. For example, if the maintenance time of TS1 is 1 minute and the maintenance time of TS2 is 1 minute, the maintenance time of TS3 can be more than 2 minutes. As described above, by rapidly decreasing rather than slowly decreasing, the viscosity of temporary adhesive portion 95 can be increased, and the bonding strength can also be increased. As the viscosity of temporary adhesive portion 95 is maximized, metal sheet 220' is more firmly bonded to movable plate 90, Figure 16 The length of the metal sheet 220 ′ further stretched in step (b) can still be maintained after the temperature drops.

[0166] described Figure 16 This is based on an embodiment of providing an internal tensile force IT to the metal sheet 220 ′ on the movable plate 90 through temperature control, but is not limited thereto. Other temperature control methods may also be used to provide the internal tensile force IT to the metal sheet 220 ′.

[0167] According to another embodiment, the metal sheet 220' can be made of an Invar alloy sheet, and the moving plate 90 can be made of a material having a thermal expansion coefficient greater than that of the Invar alloy. 33. In this case, compared to Figure 16 In the embodiment, the temperature control can be performed in the reverse direction. First, the process temperature can be lowered to a temperature at least lower than room temperature (20±5°C). The temperature lower than room temperature can include a range from sub-zero to room temperature.

[0168] In the next step, the metal sheet 220 ′ and the moving plate 90 are bonded to each other by sandwiching a temporary bonding portion 95 made of a dry film resist material.

[0169] Next, the process temperature can be raised to room temperature. During this process, due to the high coefficient of thermal expansion of movable plate 90, the metal sheet 220' is stretched to a greater degree. Since metal sheet 220' is bonded to movable plate 90, movable plate 90 is stretched further than metal sheet 220', thus applying tensile forces to all sides of metal sheet 220'. Metal sheet 220' can be bonded and supported on movable plate 90 while being subjected to lateral tensile forces.

[0170] According to another embodiment, if the metal sheet 220' is directly stretched and then bonded to the movable plate 90, the large area of ​​the movable plate 90 may bend due to the tensile force of the large area of ​​the metal sheet 220'. If the metal sheet 220' [or the unit sheet portion 220] is bonded to the movable plate 90, there is a possibility that it will bend in a concave shape toward the metal sheet 220'. In other words, there is a possibility that the movable plate 90 located at the bottom will bend downward. In this case, after the movable plate 90 is turned over and aligned with the edge frame portion 210, the upwardly bent movable plate 90 is flattened due to its own weight and pressurizes the bonded metal sheet 220' [or the unit sheet portion 220] to flatten the bent portion together. As a result, the metal sheet 220' [or the unit sheet portion 220] can be connected to the edge frame portion 210 in a taut state.

[0171] On this basis, Figure 14 The suction cup 80 may further include a heating device. The suction cup 80 generates heat, which is transferred to the metal sheet 220' and the moving plate 90. Figure 16 As described in , the metal sheet 220 ′ can also be stretched based on temperature control.

[0172] In addition, unlike the above-mentioned process of forming the mask pattern P with a tiny size, in the unit sheet portion 220, more emphasis is placed on the accurate alignment of multiple mask unit areas CR along the X-axis and Y-axis directions. The OLED pixel-forming organic matter that passes through one mask unit area CR constitutes a pixel of a display after passing through multiple mask patterns P of the mask 100. In other words, different mask unit areas CR can correspond to different displays. In order to ensure the mass production quality of OLED pixels, the X-axis and Y-axis length error range between the mask unit areas CR should be below about ±30 to 40μm. With the development of OLED technology, minimizing the frame has become a trend. In order to minimize the frame width, the edge width of the mask unit area CR, the peripheral portion of the mask 100 through which the pixel-forming organic matter passes, needs to be more constant.

[0173] In addition, if wet etching is performed during the process of forming the mask unit region CR in the unit sheet portion 220, Figure 8 As described in the above, when etching liquid enters the surface and the opposite surface based on isotropic etching, the size difference of the mask unit region CR will inevitably become larger. Based on the consideration of minimizing the frame, the dead space at the edge of the mask unit region CR where wet etching is performed needs to be minimized.

[0174] Therefore, a manufacturing method capable of reducing edge errors between mask unit regions CR and minimizing dead zones will be described below.

[0175] Figures 17 and 18FIG. 1 is a schematic diagram of a manufacturing process of a unit sheet portion according to an embodiment of the present invention. Figure 19 FIG. 1 is a schematic diagram of a unit pattern of a unit sheet portion according to an embodiment of the present invention.

[0176] For convenience of description, the following description will be made by taking the formation of one mask unit region CR in the unit sheet portion 220 as an example. However, it can also be understood that a plurality of mask unit regions CR need to be formed simultaneously.

[0177] Reference Figure 17 (a), first, a metal sheet 220' for manufacturing the unit sheet portion 220 of the frame 200 may be prepared. Figure 11 As described above, the metal sheet 220 ′ may be bonded to the movable plate 90 with a temporary bonding portion 95 (or dry film resist layer 95 ) interposed therebetween.

[0178] The metal sheet 220' serves as the unit sheet portion 220 for supporting the mask 100, and its thickness may be greater than that of the mask 100. According to one embodiment, the thickness of the metal sheet 220' may be approximately 70 μm to 200 μm. The thickness of the metal sheet 220' may be at least twice the thickness of the mask 100. In addition, within a thickness range that is greater than or more than twice the thickness of the mask 100, the thickness of the metal sheet 220' may also be determined to be approximately 50 μm to 200 μm. As an example, when the thickness of the mask 100 is approximately 2 μm to 50 μm, the thickness of the metal sheet 220' is several to dozens of times greater, and the width of the mask unit region CR [or, unit pattern CP] is tens to hundreds of mm, which is also much greater than the width of the mask pattern P of approximately tens of μm. Therefore, the wet etching process also needs to be performed in a different manner to form the mask unit region CR [or, unit pattern CP]. Thus, a process for forming at least three unit patterns Ca, Cb, and Cc is used for the unit sheet portion 220. Below, an example of forming the mask unit region CR using three unit patterns Ca, Cb, and Cc will be described, given a thickness of approximately 150 μm. However, depending on the thickness of the unit sheet portion 220, the mask unit region CR can also be formed using at least four unit patterns by adding an etching process.

[0179] A patterned first insulating portion Ma may be formed on one side (top) of the metal sheet 220'. The first insulating portion Ma may be formed of a photoresist material by a printing method or the like. The material and forming method of the first insulating portion Ma may be Figure 5 (a) Formation process of the first insulating portion M1.

[0180] Then, refer to Figure 17(b) A first unit pattern Ca having a predetermined depth can be formed on one side (top) of the metal sheet 220 by a first wet etching process WEA. When the first wet etching process WEA is performed, the metal sheet 220 should not be penetrated. Therefore, the first unit pattern Ca can be formed so as not to penetrate the metal sheet 220'a and to have a generally arc shape.

[0181] Due to the isotropic etching characteristics of the first wet etch process WEA, the width Rb of the first unit pattern Ca is not equal to the width of the spacing Ra between the patterns of the first insulating portion Ma, and is larger than the spacing Ra between the patterns of the first insulating portion Ma. In other words, due to the undercuts formed at the lower portions of both sides of the first insulating portion Ma, the width Rb of the first unit pattern Ca can be greater than the spacing Ra between the patterns of the first insulating portion M1 by the width of the undercut UC. The spacing Ra between the patterns can roughly correspond to the width of the mask unit region CR (or, the unit pattern CP), which is equivalent to tens to hundreds of millimeters.

[0182] The first unit pattern Ca may be formed to a depth of approximately 60% to 70% of the thickness of the metal sheet 220'. For example, when a metal sheet 220' having a thickness of approximately 150 μm is used, the first unit pattern Ca may be formed to a depth of approximately 90 to 105 μm. Therefore, the difference between the width Rb of the first unit pattern Ca due to the undercut and the spacing Ra between the patterns of the first insulating portion Ma may be equal to or less than the formation depth of the first unit pattern Ca.

[0183] Then, refer to Figure 17 (c) The second insulating portion Mb may be formed at least in the first unit pattern Ca. In the state where the first unit pattern Ca is formed, the process of forming the second insulating portion Mb may be performed by Figure 5 (c) and Figure 6 After forming the second insulating portion Mb on one side (top) of the metal sheet 220'c and baking and volatilizing a portion of the second insulating portion Mb, exposure L is performed from above so that the first insulating portion Ma can be used as an exposure mask. Since the second insulating portion Mb is a positive photoresist, the portion exposed L will be removed. The space left for the second insulating portion Mb can correspond to the space for forming the undercut at the lower part of both sides of the first insulating portion Ma [refer to Figure 5 (b) step]. The interval Ra between the patterns of the second insulating portion Mb may be equal to the interval Ra between the patterns of the first insulating portion Ma.

[0184] Then, refer to Figure 18(d) A second wet etching process WEb can be performed on the first unit pattern Ca of the metal sheet 220'b. The wet etching solution can penetrate the spaces between the first insulating portion Ma patterns and the spaces between the first unit patterns Ca, and the second wet etching process WEb can be performed. The second wet etching process WEb can form the second unit pattern Cb to a predetermined depth. When the second wet etching process WEb is performed, the metal sheet 220'a should not be penetrated. Therefore, the second unit pattern Cb can be formed so as not to penetrate the metal sheet 220'b and to have a generally arc shape.

[0185] Because the second wet etch process WEb has isotropic etching characteristics, the width Rc of the second unit pattern Cb is not equal to the spacing Ra between the second insulating portion Mb patterns, and is larger than the spacing Ra between the second insulating portion Mb patterns. In other words, because undercuts are formed at the lower portions of both sides of the second insulating portion Mb, the width Rc of the second unit pattern Cb can be greater than the spacing Ra between the second insulating portion Mb patterns by a width sufficient to form the undercuts.

[0186] The second unit pattern Cb may be formed to a depth of approximately 20% to 30% of the thickness of the metal sheet 220'. For example, when a metal sheet 220' having a thickness of approximately 150 μm is used, the second unit pattern Cb may be formed to a depth of approximately 30 to 45 μm. Therefore, the difference between the width Rc of the second unit pattern Cb due to undercutting and the spacing Ra between the patterns of the second insulating portion Mb may be equal to or less than the formation depth of the second unit pattern Cb.

[0187] In addition, the formation depth of the first unit pattern Ca is greater than the formation depth of the second unit pattern Cb, and the difference between the width Rb of the first unit pattern and the spacing Ra between the first insulating part Ma or the second insulating part Mb pattern may be greater than the difference between the width Rc of the second unit pattern and the spacing Ra between the first insulating part Ma or the second insulating part Mb pattern.

[0188] Then, refer to Figure 18 (e) A third insulating portion Mc may be formed at least in the second unit pattern Cb. In a state where the second unit pattern Cb is formed, the process of forming the third insulating portion Mc may be the same as that of Figure 17 The formation process of the second insulating portion Mb described in (c) is the same. The space left for the third insulating portion Mc can correspond to the space used to form undercuts at the lower portions of both sides of the second insulating portion Mb. The spacing Ra between the patterns of the third insulating portion Mc can be equal to the spacing Ra between the patterns of the first insulating portion Ma.

[0189] Then, refer to Figure 18(f) A third wet etch process WEc can be performed on the second unit patterns Cb of the metal sheet 220'b. The wet etching solution can penetrate the spaces between the third insulating portion Mc patterns and the spaces between the second unit patterns Cb, and the third wet etch process WEb can be performed. The third wet etch process WEc penetrates the metal sheet 220'b to form the third unit pattern Cc. Specifically, the third unit pattern Cc can be formed by forming an opening from the lower end of the second unit pattern Cb through the other side of the metal sheet 220'c.

[0190] Furthermore, when using liquid wax or photoresist to bond the movable plate 90 to the metal sheet 220', as in the prior art, the metal sheet 220'c surrounding the third unit pattern Cc loses contact with the liquid wax / photoresist layer during the third wet etching process WEc, resulting in a warped portion. Due to the weak adhesion between the liquid wax / photoresist layer, the warped portion can further warp. In this case, if the third wet etching solution intrudes between the warped portions, the desired third unit pattern Cc may not be formed.

[0191] However, in the present invention, the dry film resist layer 95 used to bond the movable plate 90 to the metal sheet 220' exhibits superior adhesion and corrosion resistance compared to conventional liquid wax / photoresist layers. The metal sheet 220' adheres tightly to the dry film resist layer 95 with strong adhesion, resulting in no raised portions of the metal sheet 220'c surrounding the third unit pattern Cc. This absence of raised portions allows for the clear formation of the desired third unit pattern Cc.

[0192] Because the third wet etch process WEc has isotropic etching characteristics, the width Rd of the third mask pattern Cd is not equal to the spacing Ra between the patterns of the third insulating portion Mc, and is larger than the spacing Ra between the patterns of the third insulating portion Mc. In other words, because undercuts are formed below both sides of the third insulating portion Mc, the width Rd of the third unit pattern Cc can be greater than the spacing Ra between the patterns of the third insulating portion Mc by a width sufficient to form the undercuts.

[0193] The third unit pattern Cc may be formed to a depth of approximately 10% to 20% of the thickness of the metal sheet 220 ′. For example, when the metal sheet 220 ′ is approximately 150 μm thick, the third unit pattern Cc may be formed to a depth of approximately 15 μm to 30 μm.

[0194] In addition, since the formation depth of the second unit pattern Cb is greater than the formation depth of the third unit pattern Cc, the difference between the width Rc of the second unit pattern and the spacing Ra between the patterns of the first insulating part Ma, the second insulating part Mb and the third insulating part Mc can be greater than the difference between the width Rd of the third unit pattern and the spacing Ra between the patterns of the first insulating part Ma, the second insulating part Mb and the third insulating part Mc.

[0195] Because the lower width of the third cell pattern Cc defines the width of the mask cell region CR, the smaller the difference between the width Rd of the third cell pattern and the spacing Ra between the patterns of the first insulating portion Ma, the second insulating portion Mb, and the third insulating portion Mc, the smaller the X-axis or Y-axis width error range between the mask cell regions CR. Therefore, the difference between the width Rd of the third cell pattern and the spacing Ra between the patterns of the first insulating portion Ma, the second insulating portion Mb, and the third insulating portion Mc is preferably approximately 30 μm or less.

[0196] Then, refer to Figure 19 By removing the first insulating portion Ma, the second insulating portion Mb, and the third insulating portion Mc, the production of the unit sheet portion 220 is completed. The shapes of the connected first unit pattern Ca, the second unit pattern Cb, and the third unit pattern Cc are combined to form the unit pattern CP (or the mask unit region CR).

[0197] As described above, the thickness Tc of the first unit pattern Ca may be approximately 60% to 70% of the thickness T of the unit sheet portion 220, the thickness Tb of the second unit pattern Cb may be approximately 20% to 30% of the thickness T of the unit sheet portion 220, and the thickness Ta of the third unit pattern Cc may be approximately 10% to 20% of the thickness of the unit sheet portion 220. The sum of the thicknesses of the first unit pattern Ca, the second unit pattern Cb, and the third unit pattern Cc may correspond to the thickness T of the unit sheet portion 220.

[0198] In addition, according to another embodiment, the thickness T of the first unit pattern Ca may be equal to the thickness Tb of the second unit pattern Cb. In this case, the thickness Ta of the third unit pattern Cc is also less than or equal to the thickness Tc of the first unit pattern Ca or the thickness Tb of the second unit pattern Cb, which is more beneficial for reducing the error range of the width of the opening (mask unit region CR).

[0199] The two side surfaces of the unit pattern CP (mask unit region CR) are curved. The side surfaces of the first unit pattern Ca, the second unit pattern Cb, and the third unit pattern Cc can be curved or concave. Overall, the two side surfaces of the unit pattern CP can be inclined.

[0200] More specifically, the inclination between a horizontal plane and any straight line L1 extending from the upper corner Cal of the first unit pattern Ca to the upper corner Cb1 of the second unit pattern Cb, and the inclination between a horizontal plane and any straight line L2 extending from the upper corner Cb1 of the second unit pattern Cb to the upper corner Cc1 of the third unit pattern Cc, can be non-perpendicular. Furthermore, because the thickness of the first unit pattern Ca is greater than that of the second unit pattern Cb, and due to the isotropic etching morphology, the inclination between a horizontal plane and any straight line L2 extending from the upper corner Cb1 of the second unit pattern Cb to the upper corner Cc1 of the third unit pattern Cc can be greater than the inclination between a horizontal plane and any straight line L1 extending from the upper corner Cal of the first unit pattern Ca to the upper corner Cb1 of the second unit pattern Cb.

[0201] Figure 20 FIG. 1 is a schematic diagram illustrating a state in which the mask 100 is connected to the unit sheet portion 220 according to an embodiment of the present invention.

[0202] Reference Figure 20 , the unit sheet portion 220 is welded on the edge frame portion 210 to form a weld bead WB1 and connected. In addition, the mask 100 is welded on each mask unit region CR of the unit sheet portion 220 to form a weld bead WB2, so that the mask 100 can be connected to the unit sheet portion 220. Figure 20 As a reference, the mask 100 may be connected to the upper portion of the third unit pattern Cc. That is, the opening width on the third unit pattern Cc may substantially provide the mask unit region CR.

[0203] The mask 100 may completely cover the mask cell region CR. In addition, only when the cells C of the plurality of mask patterns P of the mask 100 are formed [refer to Figure 3 ] is within the width of the mask cell region CR, the dummy portion of the mask 100 can be supported on the mask cell region CR. Therefore, the exposed area [opening width] of the third cell pattern Cc can be larger than the area of ​​the multiple mask patterns P formed on the mask 100, that is, the cell C.

[0204] The width of the mask unit region CR (or unit pattern CP) along the X-axis or Y-axis is from tens to hundreds of millimeters. Therefore, the organic matter deposited during the OLED pixel deposition process that enters from the center of the mask unit region CR has a high degree of uniformity. However, there is also the possibility that the organic matter may enter from the edge of the mask unit region CR. According to one embodiment, the inclination a3 between any straight line L1 from the upper corner Ca1 of the first unit pattern Ca to the upper corner Cb1 of the second unit pattern Cb and the horizontal plane [refer to Figure 19] can be 50° or less. That is, during the OLED pixel deposition process, deposited organic matter can enter the first unit pattern Ca, which it passes through first, along the surface with a smaller inclination of less than 50° and a wider area (arrows indicate the direction of entry of the organic matter). This reduces the amount of organic matter that scatters from the inner walls of the first unit pattern Ca and enters the center. Conversely, the amount of organic matter that enters from the corners of the unit pattern CP increases, allowing the organic matter to enter more evenly throughout the entire mask unit region CR before passing through the mask pattern P of the mask 100.

[0205] In addition, if Figure 19 As described in the foregoing, the inclination between an arbitrary straight line L2 from the upper corner Cb1 of the second unit pattern Cb to the upper corner Cc1 of the third unit pattern Cc and the horizontal plane is greater than the inclination between an arbitrary straight line L1 from the upper corner Ca1 of the first unit pattern Ca to the upper corner Cb1 of the second unit pattern Cb and the horizontal plane, so that the deposited organic matter can start to enter along a wider surface in the first unit pattern Ca and gradually concentrate toward the edge portion of the mask unit region CR. Therefore, before passing through the mask pattern P of the mask 100, the organic matter can enter the entire area of ​​the mask unit region CR more uniformly.

[0206] Figure 21 FIG. 1 is an electron microscope photograph of a unit pattern according to an embodiment of the present invention.

[0207] Reference Figure 21 As can be seen, the thickness of mask 100 is approximately 140μm. The first, second, and third unit patterns Ca, Cb, and Cc are isotropically etched, resulting in curved side surfaces. The darker layers above unit pattern CP correspond to the first, second, and third insulating portions Ma, Mb, and Mc. The angle a3 of any straight line L1 from the upper corner Ca1 of first pattern Ca to the upper corner Cb1 of second unit pattern Cb is approximately 47.8°, with a greater inclination in the lower portion. This allows organic matter entering from the corners of first unit pattern Ca to be more uniformly concentrated toward third unit pattern Cc. Organic matter that passes through third unit pattern Cc (or, mask unit region CR) can pass through mask pattern P of mask 100 and form OLED pixels on the target substrate where they are to be formed.

[0208] Figure 22 Schematic diagram of a manufacturing process of a unit sheet portion and a frame according to a comparative example. Figure 23 Based on the comparative example Figure 22 A partially enlarged schematic diagram of . Figure 23 yes Figure 22 (b) is a partially enlarged view of the upper right portion.

[0209] Reference Figure 22(a) According to the frame manufacturing process of the comparative example, first, an edge frame portion 210 is provided. The edge frame portion 210 may have a quadrangular frame shape including a hollow region R.

[0210] Then, refer to Figure 22 (b) The unit sheet portion 220' is manufactured. The unit sheet portion 220' is formed by fabricating a planar sheet using electroforming or other film-forming processes, and then removing portions of the mask unit regions CR (or, alternatively, forming unit patterns CP). For example, in the case of a 6×5 mask unit region CR (CR11-CR56), five first grid sheet portions 223 and four second grid sheet portions 225 are formed.

[0211] Then, the unit sheet portion 220' can be aligned with the edge frame portion 210. In the alignment process, by stretching the sides of the unit sheet portions F1-F4 220', the unit sheet portion 220' can be aligned with the edge sheet portion 221' of the edge frame portion 210 in a flat and unfolded state.

[0212] Then, refer to Figure 22 (b) and Figure 23 After the unit sheet portion 220' is aligned with the edge frame portion 210, the edge sheet portion 221' of the unit sheet portion 220' can be welded to form a connection. The welded portion forms a weld bead WB. The weld bead WB is made of the same material as the unit sheet portion 220' and serves as a medium for integrally connecting the edge frame portion 210 and the unit sheet portion 220'.

[0213] The comparative example does not use a component that is bonded and supported on the movable plate 90 to support the unit sheet portion 220'. After the unit sheet portion 220' is manufactured, a clamping device GP such as a gripper is connected to the side or edge of the unit sheet portion 220' and stretching F1-F4 is directly performed. In particular, in order to facilitate the application of a tensile force to the entire unit sheet portion 220', it is generally adopted to connect the clamping device GP to the ends of the first grid sheet portion 223' and the second grid sheet portion 225' and stretch them. Figure 22 As a reference, the clamping device GP can be connected to the left and right ends of the first grid sheet portion 223' and apply tensile forces F1 and F2 in the left-right direction. In addition, the clamping device GP can be connected to the upper and lower ends of the second grid sheet portion 225' and apply tensile forces F3 and F4 in the vertical direction. That is, the first tensile force F1 and the second tensile force F2 can be applied in a direction parallel to the edge of the mask unit area (the left-right direction), and the third tensile force F3 and the fourth tensile force F4 can be applied in a direction perpendicular to the edge of the mask unit area (the vertical direction). Figure 22 The arrow positions of the intermediate tensile forces F1 and F2 can be understood as the points where the tensile forces are directly applied.

[0214] As described above, by applying tensile forces F1-F4 to the respective ends of the first grid sheet portion 223' and the second grid sheet portion 225' and controlling the tensile forces of the unit sheet portion 220', the tensile forces are distributed across the entire unit sheet portion 220'. Specifically, since the tensile forces F1-F4 are adjusted at the ends (or tensile axis) of the first grid sheet portion 223' and the second grid sheet portion 225', relative to the center position of the mask cell region CR, the center of the mask cell region CR can be kept constant (uniform position over a large area). However, since the tensile forces F1-F4 are adjusted locally at the respective ends (or tensile axis) of the first grid sheet portion 223' and the second grid sheet portion 225', distortion or jagged distortion can easily occur from the perspective of each mask cell region CR (non-uniform position over a small area). It is preferable that the deviation of each side of the mask cell region CR in the actual production be maintained within a predetermined range compared to the originally designed sides at any point on the mask cell region CR.

[0215] In addition, according to the comparative example or the prior art, although the unit sheet portion 220' can be connected to the edge frame portion 210, the side of the unit sheet portion 220' needs to be stretched, and therefore a portion is required to clamp and stretch the unit sheet portion 220'. When the sides of the unit sheet portion 220' are stretched F1-F4, the clamping device GP needs a portion for clamping. As the portion clamped by the clamping device GP, the unit sheet portion 220' needs a portion that can be removed after connecting itself to the edge frame portion 210. This portion can be provided in the form of a protrusion PT. Alternatively, this portion can be provided in the form of an outer edge portion of the edge sheet portion 221', and the outer edge portion is provided with a width that exceeds the edge sheet portion 221' that is ultimately connected to the edge frame portion 210. Then, after the unit sheet portion 220' is connected to the edge frame portion 210, the portion that exceeds the width can be removed.

[0216] Figure 22 (b) and Figure 23 The first grid sheet portion 223' and the second grid sheet portion 225' of the unit sheet portion 220' are extended, and an example of a protrusion PT protruding toward the outside of the edge sheet portion 221' is shown. The protrusion PT is clamped by a clamping device GP such as a clamp, and tensile forces F1-F4 are applied. As an example, for a unit sheet portion 220' corresponding to half the size of 6G, 100 mask unit regions CR can be provided in a state of 6 first grid sheet portions 223' and 20 second grid sheet portions 225'. When a protrusion PT is formed between two mask unit regions CR, a total of 44 protrusions PT are formed in a 4×11 pattern on the outside of the edge sheet portion 221'.

[0217] After the protrusions PT are clamped on the four sides of the overall quadrilateral unit sheet portion 220' (or the four sides of the edge sheet portion 221'), tensile forces F1-F4 are applied. By applying the tensile force to the protrusions PT, the edge sheet portion 221', the first grid sheet portion 223', and the second grid sheet portion 225' are stretched, so that the unit sheet portion 220' is connected to the edge frame portion 210 in a taut state.

[0218] Figure 24 This is a schematic diagram illustrating the process of connecting a unit sheet portion to an edge frame portion according to a comparative example. The following describes the process of connecting a unit sheet portion 220' having a protrusion PT to an edge frame portion 210. For ease of explanation, the figure illustrates a portion of the edge sheet portion 221' and the mask unit region CR, while omitting the first and second grid sheet portions 223', 225', and the edge frame portion 210.

[0219] First, refer to Figure 24 (a), as mentioned above Figure 22 As shown in (a) and (b), a unit sheet portion 220' having an edge frame portion 210 and a mask unit region CR is prepared. Next, a clamp is used to clamp the protruding portion PT protruding to the outside of the edge sheet portion 221' and a tensile force F is applied. Next, as shown in Figure 24 As shown in (b), the edge sheet portion 221' is aligned with the appropriate position of the edge frame portion 210 and then welded to form a weld bead WB. The edge sheet portion 221' is connected to the edge frame portion 210 through the weld bead WB. The tensile force F should be maintained until the welding process is completed.

[0220] Next, if Figure 24 As shown in (c), the protrusion PT is removed. A cutting line CL is provided between the protrusion PT and the outer edge of the edge sheet portion 221'. The protrusion PT can be removed by physical cutting, mechanical cutting or laser cutting. The protrusion PT can be removed in a one-time process or as Figure 24 As shown in the enlarged portion of (c), a half undercut NC is first formed, and then a re-cutting process is performed along the cutting line CL or the protrusion PT is pulled outward based on the half undercut NC.

[0221] Next, if Figure 24As shown in (d), after the protrusion PT is removed, the cut surface CS1 is located at the portion of the edge sheet portion 221' where the protrusion PT was connected. Since the cut surface CS1 (or the outer edge side surface of the unit sheet portion 220') is formed by physical cutting, mechanical cutting, or laser cutting, its shape may be irregular. Specifically, while the shape of half of the undercut NC in the cut surface CS1 is maintained to a certain extent, the remaining portion is broken, resulting in an irregular shape of the cut surface CS1, and the cut surface CS1 may even remain in an upward extension.

[0222] One embodiment of the present invention adopts Figures 11 to 16 The unit sheet portion 220 [or metal sheet 220'] is bonded and supported on the movable plate 90 as described above. Instead of directly stretching the unit sheet portion 220 using a clamping device, an internal tensile force is applied by temperature control. Therefore, the unit sheet portion 220 [or metal sheet 220'] can uniformly apply tensile force IT (or internal tensile force IT, see the example of the embodiment of the present invention) in all directions or along the radial direction on the large area of ​​the movable plate 90. Figure 16 ). From another perspective, the unit sheet portion 220 can apply a more uniform tensile force IT (or include a tensile force IT) in all directions or along the radial direction based on the mask unit region CR, regardless of the first grid sheet portion 223 and the second grid sheet portion 225. In this regard, the present invention is different from Figure 22 In the comparative example, the actual tensile force exerted on the edge frame portion by the unit sheet portion 220 tightly connected to the edge frame portion 210 is uniform at all positions, regardless of the position of the protrusion PT or the clamping device GP.

[0223] Therefore, the present invention has an effect of facilitating the distribution of tensile force (uniform position within a small range) not only from the perspective of the entire unit sheet portion 220 but also from the perspective of each mask unit region CR.

[0224] Figure 25 Graphs showing the tensile forces measured when tensile forces are applied outward at various points of the unit sheet portion connected to the edge frame portion according to a comparative example and an embodiment of the present invention. Figure 26 yes Figure 25 Enlarged view of the data portion marked in .

[0225] According to the comparative example, the tensile forces applied outward from points 1 to 41 were measured after the first grid sheet portion 223' and the second grid sheet portion 225' of the F1-F4 unit sheet portion 220' were clamped and stretched at both ends by a clamping device GP and welded to the edge frame portion 210. Furthermore, according to an embodiment of the present invention, the tensile forces applied outward from points 1 to 41 were measured after the unit sheet portion 220 was bonded and supported on a movable plate 90, and the movable plate 90 was moved so that the unit sheet portion 220 was aligned with the edge frame portion 210 and welded. Because the unit sheet portions 220 and 220' were already connected to the edge frame portion 210, the 'tensile force' can be referred to as the 'residual stress' of the unit sheet portions 220 and 220'. The residual stress measurement data for the comparative example is represented by a dashed line, while the residual stress measurement data for the embodiment of the present invention is represented by a solid line.

[0226] Table 1 below shows the residual stress (tensile force) measured at points 1 to 41 of the unit sheet portions 220 and 220 ′ in the examples of the present invention and comparative examples. The numerical unit is MPa.

[0227] [Table 1]

[0228]

[0229]

[0230] Reference Figure 25 and Figure 26 , which shows a graph of residual stress in the Y-axis direction (vertical direction) along the upper sides of the unit sheet portions 220 , 220 ′ welded to the edge frame portion 210 (or the upper sides of the edge sheet portions 221 , 221 ′). Figure 26 Enlarged image Figure 25 For ease of explanation, Figure 25 The projection PT is shown, while comparing e.g. Figure 24 As described above, the protrusion PT is removed after the unit sheet portion 221' is connected to the edge frame portion 210 by welding. If the protrusion PT is removed, only the cut surface CS1 will remain in the portion of the edge sheet portion 221' to which the protrusion PT is connected.

[0231] The maximum residual stress value in the residual stress data for the comparative example (dashed line) is greater than the maximum residual stress value in the residual stress data for the example of the present invention (solid line). In particular, for the comparative example, larger deviations can be observed near points 1, 9, 17, 25, 33, and 41 compared to other points. The residual stress values ​​at points 1, 9, 17, 25, 33, and 41 are indicated in bold in Table 1 above. Figure 26 The values ​​of the corresponding points are indicated by circles.

[0232] From another perspective, the residual stress data of the comparative example (dashed line) tends to have a larger deviation in residual stress values ​​than the residual stress data of the embodiment of the present invention (solid line).

[0233] Points 1, 9, 17, 25, 33, and 41 correspond to the protrusion PT of the unit sheet 221'. Alternatively, points 1, 9, 17, 25, 33, and 41 correspond to the ends of the first and second grid sheets 223' and 225'. Figure 22 The process in which the gripping device GP grips the protruding portion PT and applies the tensile force F3 has been described in (b). The tensile force due to the tensile force F3 may remain in the unit sheet portion 220' as residual stress.

[0234] On the contrary, the embodiment of the present invention can confirm that the residual stress values ​​near points 1, 9, 17, 25, 33, and 41 are larger than those at other points. In the embodiment of the present invention, since the clamping device GP is not used to clamp and stretch the two ends of the first grid sheet portion 223 and the second grid sheet portion 225 F1-F4, the stretching effect is applied to the entire surface of the unit sheet portion 220. In other words, on the large-area movable plate 90, since the unit sheet portion 220 is subjected to a uniform tensile force IT in all directions or along the radial direction, the residual stress will also appear randomly [refer to Figures 11 to 16 ].

[0235] Table 2 below shows the residual stress differences (MPa) between Zones 1 through 6 (Z1-Z6) in the comparative example and the embodiment of the present invention, based on the residual stress values ​​in Table 1. This is the difference between the maximum and minimum values ​​of the midpoints in each zone. Z1 corresponds to Points 1 through 4, Z2 to Points 6 through 11, Z3 to Points 14 through 20, Z4 to Points 22 through 27, Z5 to Points 30 through 36, and Z6 to Points 38 through 41. In other words, each zone corresponds to the residual stress acting on the upper side of each mask cell region CR.

[0236] [Table 2]

[0237] area Z1 Z2 Z3 Z4 Z5 Z6 Comparative Example 37 43 39 45 51 34 The present invention 16 20 23 19 11 8

[0238] The difference in residual stress at each point in each of the regions Z1-Z6 between the comparative example and the present invention ranged from a minimum of approximately 1.70 times (region Z3) to a maximum of approximately 4.63 times (region Z5). It was confirmed that the straightness of one side of the mask unit region CR was lower in the comparative example than in the present invention, with the upper side of the edge sheet portion 221′ exhibiting an error in the Y-axis direction.

[0239] Compared to the comparative example, the embodiment of the present invention exhibits constant residual stress along the periphery of the unit sheet portion 220, particularly the edge sheet portion 221. However, in the comparative example, the residual stress is greater near the corners of the mask cell regions CR. In particular, for the mask cell regions CR arranged along the edge of the unit sheet portion 220', the residual stress at points 1, 9, 17, 25, 33, and 41 is greater, resulting in a more significant difference compared to the mask cell regions CR arranged inward.

[0240] Referring again to Table 1 above, the residual stresses of the comparative example at points 1, 9, 17, 25, 33, and 41 are 82, 88, 81, 92, and 87, respectively. Compared with the residual stresses of 76, 65, 72, 63, and 66 of the present invention, the values ​​of the comparative example are larger, with the minimum residual stress being approximately 7.9% higher (point 1) and the maximum being approximately 46% higher (point 33).

[0241] The unit sheet portion 220 according to the embodiment of the present invention can align the four sides and four corners of the mask unit region CR. In other words, the present invention can prevent the mask unit region CR from being distorted and maintain a uniform shape.

[0242] As described above, the present invention does not use a clamping device to directly stretch the unit sheet 220. Instead, it applies an internal tensile force through temperature control during the bonding process of the unit sheet 220 (or metal sheet 220') to the movable plate 90. Consequently, the unit sheet 220 (or metal sheet 220') exerts a uniform tensile force in all directions or along the radial direction across the large surface area of ​​the movable plate 90. This allows for accurate alignment of the mask cell region CR when the unit sheet 220 is attached to the edge frame 210.

[0243] As described above, the present invention has been illustrated and described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments. Various modifications and variations can be made by those skilled in the art without departing from the spirit of the present invention. Such modifications and variations should be deemed to fall within the scope of the present invention and the appended claims.

Claims

1. A method for manufacturing a frame used in a connection between a mask for forming an OLED pixel and a frame, the method comprising the following steps: (a) bonding a first side of a metal sheet to a movable plate; (b) forming a plurality of mask unit regions on a second surface, which is opposite to the first surface, of the metal sheet to produce a unit sheet portion; (c) connecting the unit sheet portion to an edge frame portion, the edge frame portion including a hollow area, When the process of holding the edge of the unit sheet portion and stretching it in the side direction and connecting it to the edge frame portion is used as a comparative example, After the step (c), the maximum residual stress remaining at any point on the edge of the unit sheet portion is smaller than the maximum residual stress remaining at any point on the edge of the unit sheet portion of the comparative example.

2. The frame manufacturing method according to claim 1, wherein: In the step (a), the movable plate and the metal sheet are bonded together by interposing a dry film resist layer.

3. The frame manufacturing method according to claim 2, wherein: The step of applying a tensile force to the side direction of the unit sheet portion comprises the following steps: (1) contacting the movable plate and the metal sheet at a temperature at least higher than room temperature; (2) The movable plate and the metal sheet are bonded together while the temperature is decreasing toward room temperature.

4. The frame manufacturing method according to claim 3, wherein: The step (1) comprises sandwiching a temporary bonding portion between the movable plate and the metal sheet, raising the process temperature to at least a level where the bonding strength of the temporary bonding portion is 0 to 5 kgf / cm 2 the temperature, and bringing the metal sheet into contact with the moving plate, The step (2) includes lowering the process temperature to at least a level where the bonding strength of the temporary bonding portion is greater than 5 kgf / cm 2 and bonding the metal sheet to the moving plate.

5. The frame manufacturing method according to claim 1, wherein: The movable plate comprises at least one material selected from the group consisting of glass, silicon dioxide, quartz, aluminum oxide, borosilicate glass, zirconium oxide, silicate ceramics, titanium, molybdenum, silver, copper, platinum, gold, polyimide, and polymer, or a material obtained by coating at least one of titanium, molybdenum, silver, copper, platinum, gold, polyimide, and polymer on the surface of any one of Invar, Super Invar, and stainless steel. The width×length of the movable plate is greater than 1500mm×900mm.

6. The frame manufacturing method according to claim 1, wherein: In the step (b), the unit sheet portion includes: an edge sheet portion; a plurality of first grid sheet portions, which are formed extending along a first direction and connected to the edge sheet portion at both ends; and a plurality of second grid sheet portions, which are formed extending along a second direction perpendicular to the first direction and intersecting with the first grid sheet portion and connected to the edge sheet portion at both ends. In the step (c), at least a portion of the edge sheet portion is connected to the edge frame portion.

7. The frame manufacturing method according to claim 1, wherein: The step of applying a tensile force to the side direction of the unit sheet portion comprises the following steps: (1) A suction cup provides heat to the movable plate and the metal sheet, and the suction cup is used to absorb one side of the movable plate and move the movable plate; (2) The movable plate and the metal sheet are bonded together while the suction cup interrupts or reduces the heat supply.

8. The frame manufacturing method according to claim 3 or 7, wherein: The metal sheet is bonded to the movable plate in a state where the metal sheet is elongated compared to its original length.

9. The frame manufacturing method according to claim 3 or 7, wherein: The unit sheet portion has a quadrilateral planar shape, and a tensile force is applied to all side surfaces in a radial direction.

10. The frame manufacturing method according to claim 1, wherein: After the step (c), the variation of the residual stress acting along any mask cell region is smaller than the variation of the residual stress acting along any mask cell region of the comparative example.

11. The frame manufacturing method according to claim 1, wherein: After the step (c), the residual stress value acting on the corner of any mask unit region is smaller than the residual stress value acting on the corner of any mask unit region of the comparative example.

12. The frame manufacturing method according to claim 1, wherein: The difference between the maximum and minimum values ​​of the residual stress acting along any mask unit area in the comparative example is 1.7 to 4.63 times greater than the difference between the maximum and minimum values ​​of the residual stress acting along any mask unit area after step (c).

13. The frame manufacturing method according to claim 1, wherein: The step (b) comprises the following steps: (b1) forming a patterned first insulating portion on the second surface of the metal sheet; (b2) forming a first unit pattern of a first depth on the second surface of the metal sheet by wet etching; (b3) filling a second insulating portion in at least the first unit pattern; (b4) retaining only the second insulating portion located vertically below the first insulating portion; (b5) forming a second unit pattern with a second depth on the first unit pattern on the second surface of the metal sheet by wet etching; (b6) filling a third insulating portion at least in the second unit pattern; (b7) retaining only the third insulating portion located vertically below the second insulating portion; (b8) On the second surface of the metal sheet, forming a third unit pattern with a third depth on the second unit pattern by wet etching.

14. A frame used in a connection body between a mask for forming an OLED pixel and a frame, wherein: The frame is manufactured by the following steps, including: (a) bonding a first surface of a metal sheet to a movable plate; (b) forming a plurality of mask unit areas on a second surface opposite to the first surface of the metal sheet and manufacturing a unit sheet portion; (c) connecting the unit sheet portion to an edge frame portion, the edge frame portion including a hollow area. When the process of holding the edge of the unit sheet portion and stretching it in the side direction and connecting it to the edge frame portion is used as a comparative example, The maximum value of the residual stress remaining at any point on the edge of the unit sheet portion is smaller than the maximum value of the residual stress remaining at any point on the edge of the unit sheet portion of the comparative example.

15. The frame of claim 14, wherein: The variation of the residual stress acting along any mask cell region is smaller than the variation of the residual stress acting along any mask cell region of the comparative example.

16. The frame of claim 14, wherein: The value of the residual stress acting on the corner of any mask cell region is smaller than the value of the residual stress acting on the corner of any mask cell region of the comparative example.

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