Frame manufacturing method

Abstract

The invention relates to a frame manufacturing method. A frame manufacturing method according to the present invention, which is used in a connector of a mask for OLED pixel formation and a frame, comprises 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; and (c) connecting the unit sheet portion to an edge frame portion including a hollow region.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a frame. More specifically, the method relates to a method for manufacturing a frame used in a mask-frame connector, wherein the connector includes a mask formed with a high-resolution mask pattern, can stably form the 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 parts 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 to 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 various problems of the prior art as described above, and its purpose is to provide a frame manufacturing method, which is used in a connector between a mask and a frame. The connector can prevent the mask from being deformed and can be stably supported and moved. It can also prevent the mask from being deformed such as sagging or twisting, and can accurately align it.

[0008] In addition, an object of the present invention is to provide a frame manufacturing method that can accurately align mask units and more clearly form a frame edge portion.

[0009] However, the above technical problems are only exemplary, and the scope of the present invention is not limited thereto.

[0010] Technical Solution

[0011] The above-mentioned object of the present invention is achieved through a frame manufacturing method, which is used in a connector between a mask and a frame for forming OLED pixels. 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, which is 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 including a hollow area.

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

[0013] The movable plate may be made of borosilicate glass.

[0014] The width×length dimensions of the movable plate may be at least greater than 1500 mm×900 mm.

[0015] 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), part of the edge sheet portion may be connected to the edge frame portion.

[0016] In the step (c), the unit sheet portion and the edge frame portion are connected using welding beads as a medium.

[0017] In the step (c), the unit sheet portion and the edge frame portion are connected using a metal connection portion made of at least one material selected from Cu, Ni, Au, Ag, Al, Sn, In, Bi, Zn, Sb, Ge, and Cd.

[0018] 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 having a first depth on the second surface of the metal sheet by wet etching; (b3) filling the second insulating portion at least within 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 from the first unit pattern on the second surface of the metal sheet by wet etching; (b6) filling the third insulating portion at least within 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 from the second unit pattern on the second surface of the metal sheet by wet etching.

[0019] After the step (b8), the mask unit area is formed by opening the first surface of the metal sheet, and the metal sheet is provided as the unit sheet portion having a plurality of the mask unit areas formed along a first direction and a second direction perpendicular to the first direction.

[0020] The step (b4) may include the following steps: (b4-1) volatilizing at least a portion of the second insulating portion by baking; (b4-2) exposing above the first insulating portion and retaining only the second insulating portion located vertically below the first insulating portion.

[0021] The region on the first face of the metal sheet of the third unit pattern is provided as the mask unit region for a connection mask.

[0022] An area of ​​the third unit pattern exposed on the first surface of the metal sheet is larger than an area of ​​the plurality of mask patterns formed on the mask.

[0023] The thickness of the first unit pattern is 60% to 70% of the thickness of the unit sheet portion, the thickness of the second unit pattern is 20% to 30% of the thickness of the unit sheet portion, and the thickness of the third unit pattern is 10% to 20% of the thickness of the unit sheet portion. The sum of the thicknesses of the first unit pattern, the second unit pattern, and the third unit pattern corresponds to the thickness of the unit sheet portion.

[0024] The thickness of the unit sheet portion may be 70 μm to 200 μm.

[0025] The first depth and the second depth may be equal.

[0026] A difference between the widths of the first unit pattern and the second unit pattern may be greater than a difference between the widths of the second unit pattern and the third unit pattern.

[0027] Technical Effects

[0028] The present invention 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 and 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 and 2 are front and side cross-sectional views of a frame according to an embodiment of the present invention.

[0033] Figure 3 FIG. 1 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. 4 is a schematic diagram of a mask manufacturing process according to an embodiment of the present invention.

[0036] Figure 8 Schematic diagram of the mask etching degree of 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 Schematic diagram of a frame manufacturing process according to an embodiment of the present invention.

[0040] Figures 16 and 17 FIG. 1 is a schematic diagram of a manufacturing process of a unit sheet portion according to an embodiment of the present invention.

[0041] Figure 18 FIG. 1 is a schematic diagram of a unit pattern of a unit sheet portion according to an embodiment of the present invention.

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

[0043] Figure 20 This is an electron microscope photograph of a unit pattern according to one embodiment of the present invention.

[0044] Reference numerals:

[0045] 10: Connector between mask and frame

[0046] 90: Mobile board

[0047] 95: Temporary adhesive part, dry film resist layer

[0048] 100: Mask

[0049] 110: Mask film, metal sheet

[0050] 200: Framework

[0051] 210: Edge frame

[0052] 220: Unit sheet

[0053] 220′: Metal sheet for manufacturing unit sheet

[0054] 221: Edge sheet part

[0055] 223: First grid sheet portion

[0056] 225: Second grid sheet portion

[0057] 1000: OLED pixel deposition device

[0058] C: unit, mask unit

[0059] Ca, Cb, Cc: first unit pattern, second unit pattern, third unit pattern

[0060] CP: Cell Pattern

[0061] CR: Mask cell region

[0062] Ma, Mb, Mc: first insulating part

[0063] R: Hollow area of ​​edge frame

[0064] P: mask pattern

[0065] P1, P1-1, P1-2: first mask pattern

[0066] P2, P2-1, P2-2: second mask pattern DETAILED DESCRIPTION

[0067] 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.

[0068] Hereinafter, in order to enable those skilled in the art to easily implement the present invention, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0069] 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 This is a front view of a frame according to an embodiment of the present invention. Figure 2 (a)] and side cross-sectional view [ Figure 2 (b)].

[0070] 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.

[0071] 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.

[0072] 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.

[0073] The mask 100 may also be made of materials such as invar, super invar, nickel (Ni), nickel-cobalt (Ni-Co), etc. The mask 100 may be made of a metal sheet produced by rolling or electroforming.

[0074] 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.

[0075] 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.

[0076] The thickness of the edge frame portion 210 can be greater than that of the unit sheet portion 220, and can be formed to a thickness of several millimeters to several ems. 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 mm to 5 mm.

[0077] 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 to CR56) can be provided in the planar sheet. This specification uses the example of forming a 6×5 mask unit region CR (CR11 to CR56). There can be five first grid sheet portions 223 and four second grid sheet portions 225.

[0078] 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.

[0079] 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 16 Described in.

[0080] Figure 3 FIG. 1 is a schematic diagram of a mask 100 according to an embodiment of the present invention.

[0081] 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.

[0082] 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.

[0083] Next, a process of manufacturing the mask 100 will be described.

[0084] Figure 4 It is a schematic diagram of the existing mask manufacturing process.

[0085] Reference Figure 4 , the existing mask manufacturing process only performs wet etching.

[0086] 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′.

[0087] 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.

[0088] As a result, the existing mask 100′ suffers from uneven dimensions across the mask patterns 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, respectively. Therefore, even slight dimensional differences can lead to product defects.

[0089] 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.

[0090] Figures 5 to 7 FIG. 4 is a schematic diagram of a mask manufacturing process according to an embodiment of the present invention.

[0091] 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, super invar, nickel (Ni), nickel-cobalt (Ni-Co), or the like.

[0092] 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.

[0093] 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, which is used to form a black matrix of a 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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 .

[0098] 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.

[0099] 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, like a coated film. The remaining thickness of the second insulating portion M2′ is preferably less than several μm, 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.

[0100] 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 parts M2′ will be exposed to L.

[0101] Then, refer to Figure 6 (f), if the exposure L is followed by development, the portion of the second insulating portion M2 ″ that 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] The mask pattern P is formed by combining the connected first mask pattern P1 and the second mask pattern P2 .

[0107] 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.

[0108] Figure 8 Schematic diagram of the mask etching degree of a comparative example of the present invention.

[0109] 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.

[0110] Figure 9 FIG. 4 is a schematic diagram of the mask etching degree according to an embodiment of the present invention.

[0111] Figure 9 The process up to (a) Figure 5 The process is the same as described in (a) to (b). 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.

[0112] 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.

[0113] Then, refer to Figure 9 (b), it can be confirmed that Figure 5 (c)~ Figure 6After 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 may be equal to correspond to the pattern width R3 of the first insulating part M1.

[0114] 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 thickness of the remaining metal sheet 110 is wet-etched for the second time, the pattern widths of the second insulating portions M2″-1 and M2″-2 that are wet-etched for the second time are substantially equal to the pattern widths of the first insulating portion M1 that is wet-etched for the first time.

[0115] 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.

[0116] Figure 10 2 is a schematic diagram of adjusting the cone angles a1 and a2 according to an embodiment of the present invention.

[0117] 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.

[0118] Hereinafter, the manufacturing process of the mask and frame connection body 10 of the present invention will be further described.

[0119] Figures 11 to 15 Schematic diagram of a frame manufacturing process according to an embodiment of the present invention.

[0120] 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.

[0121] 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 Like (a)], it can be invar, super invar, nickel (Ni), nickel-cobalt (Ni-Co), etc.

[0122] The metal sheet 220' is used as the unit sheet portion 220 for supporting the mask 100, and its thickness may be greater than that of the mask 100. The thickness of the metal sheet 220' is greater than that of the mask 100 and is approximately 70 μm to 200 μm.

[0123] 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 support the metal sheet 220' as a whole, the movable plate 90 is a flat plate with an area greater than or equal to that of the metal sheet 220'.

[0124] As an example, the width×height of 6G can be about 1500mm×1800mm, and half of 6G can be about 1500mm×900mm. Figure 1The 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.

[0125] The movable plate 90 may be made of a material that is transparent to the laser light L. Examples of materials that can be used include glass, silica, quartz, aluminum oxide (Al 2 O 3 ), borosilicate glass, and zirconium oxide.

[0126] 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 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'.

[0127] 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) of 60 seconds may be performed at a temperature of approximately 60°C 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.

[0128] The present invention utilizes a dry film resist 95 to perform bonding and photolithography processes at low temperatures below approximately 60°C, effectively preventing heat-induced deformation of the metal sheet 200' during the process. Furthermore, the use of dry film resist 95 significantly reduces baking and exposure times compared to liquid photoresist. While degassing and baking with liquid photoresist takes approximately one hour, using dry film resist only requires approximately two minutes, significantly reducing process time.

[0129] 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 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 to form a pattern for etching. 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 supporting the mask metal film.

[0130] 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 etching resistance and adhesion to the metal sheet 220′ during the formation of the third unit pattern Cc.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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 a vacuum suction cup (not shown).

[0135] 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.

[0136] 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.

[0137] Then, refer to Figure 15 After connecting the unit sheet portion 220 and the edge frame portion 210, the movable plate 90 is separated from the unit sheet portion 220 (debonding). The unit sheet portion 220 and the movable plate 90 can be separated by heating, chemically treating, applying ultrasound, or applying ultraviolet light to the temporary adhesive portion 95 [or the dry film resist layer 95]. By heating, chemically treating, applying ultrasound, or applying ultraviolet light 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.

[0138] Therefore, if Figure 15 (a) [lateral cross-sectional view], Figure 15As 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 .

[0139] 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, with the unit sheet portion 220 bonded and supported thereon, can be loaded onto the edge frame portion 210. At this time, 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.

[0140] 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 materials and can easily form thin films, but is not limited thereto.

[0141] 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.

[0142] 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.

[0143] The heat treatment can be performed at a temperature of about 200°C to 800°C, and more preferably at a temperature of about 200°C to 400°C, which is a low temperature range.

[0144] 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.

[0145] 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 side surfaces of the unit sheet portion 220 are directly stretched, this prior art method suffers from a problem of increased alignment errors between the mask unit regions CR.

[0146] 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.

[0147] 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 a 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 error range of the X-axis and Y-axis lengths between the mask unit areas CR should be below about ±30 to 40 μm. With the development of OLED technology, minimizing the border has become a trend. In order to minimize the border 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.

[0148] 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.

[0149] Therefore, a manufacturing method capable of reducing edge errors between mask unit regions CR and minimizing dead zones will be described below.

[0150] Figures 16 and 17FIG. 1 is a schematic diagram of a manufacturing process of a unit sheet portion according to an embodiment of the present invention. Figure 18 FIG. 1 is a schematic diagram of a unit pattern of a unit sheet portion according to an embodiment of the present invention.

[0151] 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.

[0152] Reference Figure 16 (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 the temporary bonding portion 95 (or dry film resist layer 95 ) interposed therebetween.

[0153] The metal sheet 220' is used 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 times to dozens of times greater, and the width of the mask unit region CR [or, unit pattern CP] is in the range of tens of mm 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 employed in the unit sheet portion 220. Below, an example of forming the mask unit region CR using the 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.

[0154] 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.

[0155] Then, refer to Figure 16(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.

[0156] Because the first wet etch process WEA has isotropic etching characteristics, 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, because undercuts are 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 patterns can roughly correspond to the width of the mask cell region CR (or, the unit pattern CP), equivalent to tens to hundreds of millimeters.

[0157] 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 depth of the first unit pattern Ca.

[0158] Then, refer to Figure 16 (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.

[0159] Then, refer to Figure 17(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 patterns of the first insulating portion Ma and the spaces between the first unit patterns Ca and perform the second wet etching process WEb. 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] Then, refer to Figure 17 (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 16 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.

[0164] Then, refer to Figure 17(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 patterns of the third insulating portion Mc 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 penetrating the other side of the metal sheet 220'c from the lower end of the second unit pattern Cb through the bottom end of the second unit pattern Cb.

[0165] 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.

[0166] 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 etching 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] Then, refer to Figure 18 By removing the first insulating portion Ma, the second insulating portion Mb, and the third insulating portion Mc, 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 a unit pattern CP (or a mask unit region CR).

[0172] 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.

[0173] 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).

[0174] 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.

[0175] More specifically, the inclination between a horizontal plane and any straight line L1 extending from the upper corner Ca1 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 Ca1 of the first unit pattern Ca to the upper corner Cb1 of the second unit pattern Cb.

[0176] Figure 19 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.

[0177] Reference Figure 19 , 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 19 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.

[0178] 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.

[0179] The width of the mask unit region CR (or unit pattern CP) along the X-axis or Y-axis is tens to hundreds of mm. 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 18] 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.

[0180] In addition, if Figure 18 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.

[0181] Figure 20 This is an electron microscope photograph of a unit pattern according to one embodiment of the present invention.

[0182] Reference Figure 20 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.

[0183] 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 of the metal sheet, which is opposite to the first surface, to produce a unit sheet portion; (c) Connecting the unit sheet portion to an edge frame portion including a hollow area.

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 1, wherein: The movable plate is made of borosilicate glass.

4. The frame manufacturing method according to claim 1, wherein: The width×length dimensions of the movable plate are at least greater than 1500 mm×900 mm.

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

6. The frame manufacturing method according to claim 1, wherein: In the step (c), the unit sheet portion and the edge frame portion are connected using welding beads as a medium.

7. The frame manufacturing method according to claim 1, wherein: In the step (c), the unit sheet portion and the edge frame portion are connected using a metal connection portion comprising at least one material of Cu, Ni, Au, Ag, Al, Sn, In, Bi, Zn, Sb, Ge, and Cd as a medium.

8. 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 having a first depth on the second surface of the metal sheet by wet etching; (b3) filling a second insulating portion at least within 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 from 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) forming a third unit pattern having a third depth from the second unit pattern on the second surface of the metal sheet by wet etching.

9. The frame manufacturing method according to claim 8, wherein: After the step (b8), the mask unit area is formed by opening the first surface of the metal sheet, and the metal sheet is provided as the unit sheet portion having a plurality of the mask unit areas formed along a first direction and a second direction perpendicular to the first direction.

10. The frame manufacturing method according to claim 8, wherein: The step (b4) comprises the following steps: (b4-1) volatilizing at least a portion of the second insulating portion by baking; (b4-2) Exposure is performed above the first insulating portion, and only the second insulating portion located vertically below the first insulating portion remains.

11. The frame manufacturing method according to claim 8, wherein: The region on the first face of the metal sheet of the third unit pattern is provided as the mask unit region for a connection mask.

12. The frame manufacturing method according to claim 8, wherein: An area of ​​the third unit pattern exposed on the first surface of the metal sheet is larger than an area of ​​the plurality of mask patterns formed on the mask.

13. The frame manufacturing method according to claim 8, wherein: The thickness of the first unit pattern is 60% to 70% of the thickness of the unit sheet portion, the thickness of the second unit pattern is 20% to 30% of the thickness of the unit sheet portion, and the thickness of the third unit pattern is 10% to 20% of the thickness of the unit sheet portion. The sum of the thicknesses of the first unit pattern, the second unit pattern, and the third unit pattern corresponds to the thickness of the unit sheet portion.

14. The frame manufacturing method according to claim 1, wherein: The thickness of the unit sheet portion is 70 μm to 200 μm.

15. The frame manufacturing method according to claim 8, wherein: The first depth is equal to the second depth.

16. The frame manufacturing method according to claim 8, wherein: A difference between the widths of the first unit pattern and the second unit pattern is greater than a difference between the widths of the second unit pattern and the third unit pattern.

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