Mask assembly and method for manufacturing the mask assembly

Abstract

A mask assembly and a method of manufacturing the mask assembly are provided. The mask assembly includes: a mask frame having a first opening at its center and including an outer frame surrounding the first opening and having at least one recess; a mask body disposed corresponding to the first opening and having a plurality of second openings having an area smaller than the first opening in a plane; a first sub-mask disposed on the upper part of the mask body, having a plurality of third openings having an area smaller than each of the second openings in a plane on its entire surface, and formed using a metallic material; a second sub-mask disposed on the upper part of the first sub-mask, having a plurality of fourth openings having an area smaller than each of the third openings in a plane on its entire surface, and formed using a polymer material; and a welding portion disposed inside the at least one recess on the upper part of the second sub-mask, thereby providing a large mask assembly with low weight.

Description

Technical Field

[0001] The present invention relates to a mask assembly and a method for manufacturing the mask assembly, and more specifically, to a mask assembly including a polyimide layer and a method for manufacturing the mask assembly. Background Technology

[0002] The display panel comprises multiple pixels. Each pixel includes driving elements such as transistors and display elements such as organic light-emitting diodes. Display elements can be formed by stacking electrodes and light-emitting patterns on a substrate.

[0003] The luminescent pattern is patterned using a mask with defined through-holes to form a predetermined area. The luminescent pattern can be formed in the area exposed by the through-holes. The shape of the luminescent pattern can be controlled according to the shape of the through-holes. Recently, to improve the production yield of display panels including luminescent patterns, technologies related to materials and manufacturing methods for manufacturing large-area masks are being developed. Summary of the Invention

[0004] The purpose of this invention is to provide a mask assembly that can achieve both low weight and large size, and a method for manufacturing the mask assembly.

[0005] One embodiment provides a mask assembly comprising: a mask frame having a first opening at its center and including an outer frame surrounding the first opening and having at least one recess; a mask body disposed corresponding to the first opening and having a plurality of second openings having an area smaller than the first opening in a plane; a first sub-mask disposed on the upper part of the mask body, having a plurality of third openings having an area smaller than each of the second openings in a plane on its entire surface, and being formed of a metallic material; a second sub-mask disposed on the upper part of the first sub-mask, having a plurality of fourth openings having an area smaller than each of the second openings in a plane on its entire surface, and being formed of a polymeric material; and a welding portion disposed on the upper part of the second sub-mask inside the at least one recess.

[0006] The second submask may include polyimide.

[0007] The coefficient of thermal expansion of the second sub-mask can be below 2 ppm / ℃.

[0008] Each of the fourth openings can be defined in correspondence with each of the third openings.

[0009] Each of the second openings may overlap with one of the third openings.

[0010] The first submask may include: a plurality of first metal lines extending along a first direction and arranged along a second direction perpendicular to the first direction; and a plurality of second metal lines extending along the second direction and arranged along the first direction, wherein each of the first metal lines and each of the second metal lines may intersect each other.

[0011] The vertical relationship between each of the first metal wires and the second metal wires can be alternating, and the vertical relationship between each of the second metal wires and the first metal wires can be alternating.

[0012] On a plane, the area of ​​each of the third openings can be greater than or equal to the area of ​​each of the fourth openings.

[0013] The thickness of the first sub-mask can be greater than 2μm and less than 5μm.

[0014] The thickness of the second sub-mask can be greater than 5 μm and less than 30 μm.

[0015] The depth of the recess along the thickness direction of the outer frame can be greater than the sum of the thicknesses of the first sub-mask, the second sub-mask, and the welded portion.

[0016] The recess may include a curved section in cross-section.

[0017] One embodiment provides a mask assembly comprising: a mask frame having a first opening at its center and including an outer frame surrounding the first opening and having at least one recess; a mask body disposed corresponding to the first opening and having a plurality of second openings having an area smaller than the first opening in a plane; a first sub-mask disposed on the upper part of the mask body, having a plurality of third openings having an area smaller than the second openings in a plane on its entire surface and being formed of a metallic material; a second sub-mask disposed on the upper part of the first sub-mask, having a plurality of fourth openings having an area smaller than the third openings in a plane on its entire surface and being formed of a polymeric material; and at least one weldment disposed on the upper part of the second sub-mask, wherein the outer frame includes: a first portion overlapping the first sub-mask, the second sub-mask, and the weldment; and a second portion overlapping the first sub-mask and the second sub-mask but not overlapping the weldment, wherein the thickness of the first portion is less than the thickness of the second portion.

[0018] The at least one recess can be a plurality of recesses, and the at least one welded portion can be a plurality of welded portions. The first portion can be defined with the plurality of recesses recessed along the thickness direction, and each of the welded portions can overlap with each of the recesses.

[0019] The second submask may include polyimide.

[0020] The mask frame and the mask body may comprise the same metal.

[0021] The metal may be Invar steel.

[0022] One embodiment provides a method for manufacturing a mask assembly, the method comprising the following steps: providing a mask frame having a first opening defined at its center and including an outer frame surrounding the first opening and having a recess defined therearound; arranging a mask body having a plurality of second openings with an area smaller than the first opening on a plane corresponding to the first opening of the mask frame; arranging a first sub-mask on the upper part of the mask body having a plurality of third openings with an area smaller than the second openings on a plane on its entire surface; arranging a second sub-mask on the upper part of the first sub-mask having a plurality of fourth openings with an area smaller than the third openings on a plane on its entire surface; arranging a metal rod on the second sub-mask inside the recess; and welding the mask frame, the first sub-mask, the second sub-mask, and the metal rod in a region overlapping with the recess.

[0023] The step of arranging the first sub-mask may include the following steps: stretching the first sub-mask so that the recess overlaps with the first sub-mask.

[0024] The step of arranging the second sub-mask may include the following steps: stretching the second sub-mask such that the recess overlaps with the second sub-mask, and each of the third openings overlaps with each of the fourth openings.

[0025] The step of arranging the second sub-mask on top of the first sub-mask may include the following steps: providing a glass substrate; providing a polymer layer on top of the glass substrate; patterning the polymer layer to form the fourth opening to form the second sub-mask; arranging the second sub-mask on top of the first sub-mask in a manner that exposes the glass substrate to the outside; and removing the exposed glass substrate.

[0026] The step of forming the second sub-mask may include the following steps: patterning the polymer layer using laser etching or dry etching.

[0027] One embodiment of the mask assembly includes a mask formed from a polymer material and a mask formed from a metallic material, thereby enabling the provision of a large, lightweight mask assembly.

[0028] One embodiment of the method for manufacturing a mask assembly includes the step of arranging a mask formed of a polymer material on top of a mask formed of a metallic material, thereby enabling the provision of a method for manufacturing large, lightweight mask assemblies. Attached Figure Description

[0029] Figure 1 This is a plan view of a mask assembly according to one embodiment.

[0030] Figure 2 This is an exploded perspective view of a mask assembly according to one embodiment.

[0031] Figure 3 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken by the I-I' line is shown.

[0032] Figure 4 Observe from below Figure 3 A diagram of the mask assembly is shown.

[0033] Figure 5 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken from line II-II' is shown.

[0034] Figure 6 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken from line III-III' is shown.

[0035] Figure 7 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken from line III-III' is shown.

[0036] Figure 8 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken from line II-II' is shown.

[0037] Figure 9 This is a flowchart of a method for manufacturing a mask assembly according to one embodiment.

[0038] Figure 10 This is a diagram schematically illustrating one step of a method for manufacturing a mask assembly.

[0039] Figure 11 This is a diagram schematically illustrating one step of a method for manufacturing a mask assembly.

[0040] Figure 12 This is a diagram schematically illustrating one step of a method for manufacturing a mask assembly.

[0041] Figure 13 This is a diagram schematically illustrating one step of a method for manufacturing a mask assembly.

[0042] Figure 14 This is a diagram schematically illustrating one step of a method for manufacturing a mask assembly.

[0043] Figure 15 This is a flowchart illustrating in detail the steps of arranging a second sub-mask on top of a first sub-mask according to one embodiment.

[0044] Figure 16 It is shown schematically. Figure 15 A flowchart of one step.

[0045] Figure 17 It is shown schematically. Figure 15 A flowchart of one step.

[0046] Figure 18 It is shown schematically. Figure 15 A flowchart of one step.

[0047] Explanation of reference numerals in the attached figures:

[0048] MA: Mask Component; FR: Mask Frame

[0049] O-FR: Outer frame; OP-FR: First opening

[0050] MK: Mask body OP-MK: Second opening

[0051] ML: First submask H-ML: Third opening

[0052] RL: Second submask H-RL: Fourth opening

[0053] MS: Welding Section Detailed Implementation

[0054] This invention can be modified in various ways and can have many forms. Therefore, specific embodiments are shown in the accompanying drawings and described in detail herein. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of this invention.

[0055] In this specification, when it is mentioned that a certain component (or region, layer, part, etc.) is "above" another component or "connected" or "combined" with another component, it means that it can be directly arranged on or directly connected / combined with another component, or a third component can be arranged between them.

[0056] In addition, in this application, "direct arrangement" can mean that there is no additional layer, film, region, plate, etc. between one part of a layer, film, region, plate, etc. and another part. For example, "direct arrangement" can mean that it is arranged between two layers or two parts without the use of additional parts such as adhesive parts.

[0057] The same reference numerals refer to the same constituent elements. Furthermore, in the drawings, the thickness, proportions, and dimensions of the constituent elements are exaggerated for the purpose of effectively illustrating the technical content.

[0058] "And / or" includes all combinations of more than one that can be defined in relation to the related composition.

[0059] The terms "first," "second," etc., can be used to describe various constituent elements, but the constituent elements should not be limited by the terms. The terms are used only to distinguish one constituent element from another. For example, without departing from the scope of the invention, a first constituent element can be named a second constituent element, and similarly, a second constituent element can be named a first constituent element. Singular expressions include plural expressions unless the context explicitly indicates a different meaning.

[0060] Furthermore, terms such as "below," "lower side," "above," and "upper side" are used to describe the relationships between the components shown in the accompanying drawings. These terms are relative concepts and are described based on the directions indicated in the drawings. In this description, "arranged above" can refer to the case where it is arranged above or below any component.

[0061] Unless otherwise defined, all terms (including technical and scientific terms) used in this specification shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, terms identical to those defined in commonly used dictionaries shall be interpreted as having the same meaning as in the context of the relevant art, and shall be interpreted as expressly defined herein, unless interpreted as having an ideal or overly formal meaning.

[0062] Terms such as “including” or “having” should be understood as: used to specify the presence of features, figures, steps, operations, constituent elements, components or combinations thereof described in the specification, rather than precluding the presence or possibility of one or more other features or figures, steps, operations, constituent elements, components or combinations thereof.

[0063] Hereinafter, with reference to the accompanying drawings, a mask assembly and a method for manufacturing the mask assembly according to an embodiment will be described.

[0064] Figure 1 This is a plan view of a mask assembly MA according to one embodiment. Figure 2 This is an exploded perspective view of a mask assembly MA according to one embodiment.

[0065] Reference Figure 1 and Figure 2 One embodiment of the mask assembly MA includes a mask frame FR, a mask body MK, a first sub-mask ML, a second sub-mask RL, and a welding part MS.

[0066] The mask frame FR may have a first opening OP-FR defined at its center in the plane, extending along the thickness direction (i.e., the third direction DR3), and may include an outer frame O-FR surrounding the first opening OP-FR (see reference). Figure 5 The outer frame O-FR can have a quadrilateral shape, and the shape of the first opening OP-FR can be defined according to the shape of the outer frame O-FR. The length of the side of the outer frame O-FR extending along the first direction DR1 can be less than the length of the side extending along the second direction DR2. Although Figure 2 The illustration shows the outer frame O-FR as having a quadrilateral shape when viewed in a plane; however, this is merely exemplary, and embodiments are not limited thereto. For example, the shape of the outer frame O-FR may include a curved surface.

[0067] In the mask frame FR, at least one recess CU-FR may be defined on one side of the outer frame O-FR. The recess CU-FR may be a recessed portion that is recessed from one side of the outer frame O-FR along the thickness direction. The shape of the recess CU-FR in the plane may be a rectangular shape in which the length of the side extending along the first direction DR1 is greater than the length of the side extending along the second direction DR2. However, this is only exemplary, and the present invention is not limited thereto. The shape of the recess CU-FR in the plane may be a square shape in which the length of the side extending along the first direction DR1 is the same as the length of the side extending along the second direction DR2, or it may be a rectangular shape in which the length of the side extending along the second direction DR2 is less than the length of the side extending along the first direction DR1, or it may be a shape including a curved surface.

[0068] The mask frame FR can be formed using Invar steel. However, this is merely exemplary, and the embodiments are not limited as long as the material is capable of accommodating the mask body MK and supporting the first sub-mask ML and the second sub-mask RL arranged on the upper part of the mask frame FR.

[0069] Furthermore, in this specification, the directions indicated by the first direction axis to the third direction axis DR1, DR2, DR3 are relative concepts and can be converted to other directions. Hereinafter, the directions from the first direction to the third direction are the directions indicated by the first direction axis to the third direction axis DR1, DR2, DR3, and will be referred to with reference to the same reference numerals.

[0070] The mask body MK can be arranged corresponding to the first opening OP-FR defined in the mask frame FR. That is, the shape of the mask body MK in the plane can correspond to the shape of the first opening OP-FR defined in the mask frame FR. The width of the mask body MK in the first direction DR1 and the width of the mask body MK in the second direction DR2 can be smaller than the width of the outer frame O-FR in the first direction DR1 and the width of the outer frame O-FR in the second direction DR2. The length of the side of the mask body MK extending along the first direction DR1 can be smaller than the length of the side extending along the second direction DR2. However, this is only exemplary, and the embodiment is not limited thereto.

[0071] The mask body MK can be defined with multiple second openings OP-MK extending along the thickness direction. The area of ​​each second opening OP-MK on the plane can be smaller than the area of ​​the first opening OP-FR on the plane. Multiple second openings OP-MK can overlap with the first opening OP-FR. Although Figure 2 The illustration shows a case where the second opening OP-MK has a rectangular shape when viewed in a plane; however, this is merely exemplary, and the embodiments are not limited thereto. For example, when viewed in a plane, the shape of the second opening OP-MK can be circular, square, or polygonal.

[0072] The mask body MK can be formed using the same material as the mask frame FR. The mask body MK can be formed using Invar steel. However, this is merely exemplary, and the embodiments are not limited thereto. In one embodiment, the mask body MK and the mask frame FR can be formed using different materials with similar coefficients of thermal expansion. Having similar coefficients of thermal expansion for the mask body MK and the mask frame FR can reduce the risk of damage to the mask assembly MA during the stretching process of the first sub-mask ML or the second sub-mask RL, described later.

[0073] The first sub-mask ML can be arranged on the upper part of the mask body MK. The width of the first sub-mask ML in the second direction DR2 can be smaller than the width of the mask frame FR in the second direction DR2. The first sub-mask ML can be formed using a metallic material. For example, the first sub-mask ML can be formed using Invar steel.

[0074] In the first sub-mask ML, multiple third openings H-MLs extending along the thickness direction can be defined across the entire surface of the first sub-mask ML. The area of ​​each third opening H-ML on the plane can be smaller than the area of ​​each second opening OP-MK on the plane. Multiple third openings H-MLs can overlap with one second opening OP-MK. Although Figure 2 The illustration shows a case where the third opening H-ML has a quadrilateral shape when viewed in a plane, but this is merely exemplary and the embodiments are not limited thereto.

[0075] The second submask RL can be disposed above the first submask ML. The width of the second submask RL in the second direction DR2 can be smaller than the width of the mask frame FR in the second direction DR2. The second submask RL can be formed using a polymer material. The coefficient of thermal expansion of the polymer material can be below 2 ppm / ℃. For example, the second submask RL can include polyimide.

[0076] In the second sub-mask RL, multiple fourth openings H-RL extending along the thickness direction can be defined across the entire surface of the second sub-mask RL. The area of ​​each fourth opening H-RL on the plane can be smaller than the area of ​​each third opening H-ML on the plane. Although Figure 2 The illustration shows the fourth opening H-RL having an octagonal shape when viewed in a plane; however, this is merely exemplary, and the embodiments are not limited thereto. For example, in one embodiment, the fourth opening H-RL may have a circular, quadrilateral, or polygonal shape when viewed in a plane.

[0077] In the case where the mask assembly only includes a second sub-mask RL formed of polymer, the vertical movement of the magnet portion arranged above the second sub-mask RL is restricted during the deposition process, thus limiting its application in the deposition process. Although not illustrated, in one embodiment of the mask assembly MA, a first sub-mask ML formed of metal is arranged below the second sub-mask RL formed of polymer. Therefore, during the deposition process, the second sub-mask RL moves together with the first sub-mask ML, which moves vertically via the magnet arranged above the second sub-mask RL, thereby increasing its applicability in the deposition process.

[0078] The weldment MS can be positioned on top of the second sub-mask RL. The weldment MS can overlap with the first sub-mask ML, the second sub-mask RL, and the outer frame O-FR. The weldment MS can be positioned at the overlap of the recess CU-FR between the second sub-mask RL and the outer frame O-FR. The weldment MS can be formed using Invar steel.

[0079] Figure 3 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken by the I-I' line is shown. Figure 4 Observe from below Figure 3 A diagram of the mask assembly is shown.

[0080] Reference Figure 3 and Figure 4In one embodiment, the first sub-mask ML may include a plurality of first metal lines ML1 extending along a first direction DR1 and arranged along a second direction DR2, and a plurality of second metal lines ML2 extending along the second direction DR2 and arranged along the first direction DR1. Each first metal line ML1 may extend along the first direction DR1 in an alternating vertical relationship with the second metal lines ML2, and each second metal line ML2 may extend along the second direction DR2 in an alternating vertical relationship with the first metal lines ML1. That is, the first metal lines ML1 and the second metal lines ML2 may intersect each other to form a lattice structure. A third opening H-ML may be defined in the space formed by the intersection of the metal lines extending along the first direction DR1 and the metal lines extending along the second direction DR2.

[0081] In one embodiment of the mask assembly MA, the second opening OP-MK, the third opening H-ML, and the fourth opening H-RL can overlap each other. One second opening OP-MK can overlap with multiple third openings H-ML and multiple fourth openings H-RL. Each fourth opening H-RL is defined in a region of the second sub-mask RL corresponding to a third opening H-ML. That is, a third opening H-ML can be defined in a one-to-one correspondence with a fourth opening H-RL. The area of ​​each third opening H-ML can be greater than or equal to the area of ​​each fourth opening H-RL. That is, on a plane, the fourth opening H-RL can be entirely exposed through the third opening H-ML.

[0082] Figure 5 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken from line II-II' is shown. Figure 6 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken from line III-III' is shown.

[0083] Reference Figure 5 and Figure 6 In one embodiment, the thickness T1 of the first sub-mask ML can be less than the thickness T2 of the second sub-mask RL. The thickness T1 of the first sub-mask ML can be 2 μm or more and 5 μm or less. The thickness T2 of the second sub-mask RL can be 5 μm or more and 30 μm or less.

[0084] The depth T4 of the recess CU-FR, defined recessed along the thickness direction of the outer frame O-FR, can be greater than the sum of the thickness T1 of the first sub-mask ML, the thickness T2 of the second sub-mask RL, and the thickness T3 of the weldment MS. Since the depth T4 of the recess CU-FR is greater than the sum of the thickness T1 of the first sub-mask ML, the thickness T2 of the second sub-mask RL, and the thickness T3 of the weldment MS, the weldment MS, located on the upper part of the second sub-mask RL, does not need to protrude along the thickness direction. That is, the weldment MS can be located inside the recess CU-FR.

[0085] In one embodiment, the outer frame O-FR may include a first portion PA1 that overlaps with the weldment MS and a second portion PA2 that does not overlap with the weldment MS. The thickness T5 of the first portion PA1 may be less than the thickness T6 of the second portion PA2. Due to the thickness difference between the first portion PA1 and the second portion PA2, a recess CU-FR may be defined in the first portion PA1. In one embodiment, the outer frame O-FR may define a recess CU-FR, and a weldment MS may be arranged corresponding to the recess CU-FR. However, this is merely exemplary, and the embodiments are not limited thereto. For example, in one embodiment, multiple weldments may be arranged corresponding to one recess CU-FR.

[0086] Figure 7 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken along line III-III' is shown below. Refer to the following... Figure 7 A mask assembly according to one embodiment will be described in detail. Further descriptions and references will not be provided. Figures 1 to 6 For content that is the same as above, the explanation will focus on the differences.

[0087] and Figures 1 to 6 A mask assembly MA (shown in one embodiment) Figure 1 Different, Figure 7 The mask assembly MA-1 of one embodiment shown has a plurality of recesses CU1-FR-1, CU2-FR-1 defined on the outer frame O-FR-1, and a plurality of weld portions MS1, MS2 are arranged inside each of the plurality of recesses CU1-FR-1, CU2-FR-1.

[0088] Reference Figure 7 In one embodiment, the mask assembly MA-1 may define multiple recesses CU1-FR-1, CU2-FR-1 on the outer frame O-FR-1. Multiple welding portions MS1, MS2 may be arranged inside each of the multiple recesses CU1-FR-1, CU2-FR-1. Although Figure 7Two recesses CU1-FR-1 and CU2-FR-1 and two welded portions MS1 and MS2 are shown, but this is only exemplary and the embodiments are not limited thereto. For example, in one embodiment, more than three recesses may be defined on the outer frame and more than three welded portions may be arranged in each recess.

[0089] Figure 8 It is a mask assembly of one embodiment along Figure 2 The cross-sectional view taken along line II-II' is shown below. Refer to the following... Figure 8 A mask assembly according to one embodiment will be described in detail. The descriptions referenced above will not be repeated. Figures 1 to 6 For content that is the same, focus on the differences in the explanation.

[0090] and Figures 1 to 6 A mask assembly MA (shown in one embodiment) Figure 1 Different, Figure 8 When viewed in a plane, the mask assembly MA-2 of one embodiment shown has a curved shape in the recess CU-FR-2 defined by the outer frame O-FR-2.

[0091] Reference Figure 8 In one embodiment, the mask assembly MA-2 may have a recess CU-FR-2 defined on the outer frame O-FR-2, having a curved surface CP and recessed along the thickness direction. The curved surface CP may be connected to the first opening OP-FR in the outer frame O-FR-2. Figure 2 Adjacent surfaces are adjacent. Since the recess CU-FR-2 includes a curved surface CP, damage to the first sub-mask ML and the second sub-mask RL can be reduced compared to cases with angled shapes.

[0092] Figure 9 This is a flowchart of a method for manufacturing a mask assembly according to one embodiment. Figures 10 to 14 This diagram schematically illustrates the steps involved in manufacturing a mask assembly. The following refers to... Figures 9 to 14 A method for manufacturing a mask assembly according to one embodiment will be described in detail. Further descriptions and references will not be provided. Figures 1 to 8 The structural features of the mask assembly are described, and the characteristics of the manufacturing method of the mask assembly are described in detail.

[0093] Reference Figure 9One embodiment of the mask assembly manufacturing method includes the following steps: providing a mask frame (S100); arranging a mask body corresponding to a first opening of the mask frame (S300); arranging a first sub-mask on the upper part of the mask body (S500); arranging a second sub-mask on the upper part of the first sub-mask (S700); arranging a metal rod on the upper part of the second sub-mask (S900); and welding the mask frame, the first sub-mask, the second sub-mask, and the metal rod (S1100).

[0094] Figure 10 This is a diagram schematically illustrating the steps of providing the mask frame (S100). Figure 11 This diagram schematically illustrates the steps of arranging the mask body (S300) corresponding to the first opening of the mask frame. (Refer to...) Figure 10 and Figure 11 One embodiment of the method for manufacturing a mask assembly may include the step of arranging a mask body MK (S300) corresponding to a first opening OP-FR of a mask frame FR.

[0095] Figure 12 This diagram schematically illustrates the steps of arranging the first sub-mask (S500) on the upper part of the mask body. (Refer to...) Figure 12 The step of arranging the first sub-mask ML on the upper part of the mask body MK can be a step of arranging the first sub-mask ML to overlap with the entire mask body MK. Alternatively, the step of arranging the first sub-mask ML on the upper part of the mask body MK can be a step of arranging the first sub-mask ML to partially overlap with the outer frame O-FR.

[0096] The step of arranging the first sub-mask ML on the upper part of the mask body MK may include stretching the first sub-mask ML so that the recess CU-FR defined in the outer frame O-FR overlaps with the first sub-mask ML. Stretching the first sub-mask ML may be a step of stretching the first sub-mask ML along a first direction DR1 and a second direction DR2 so that the first sub-mask ML overlaps with the entire surface of the mask body MK. Although not illustrated, stretching the first sub-mask ML may be a step of stretching the first sub-mask ML by heating. However, this is merely exemplary, and the method of stretching the first sub-mask ML is not limited thereto.

[0097] The step of stretching the first sub-mask ML can be a step of stretching the first sub-mask ML to align the first sub-mask ML with the mask body MK and the mask frame FR in order to perform a welding step as a subsequent process.

[0098] Figure 13 This diagram schematically illustrates the steps of arranging the second sub-mask on top of the first sub-mask. (Refer to...) Figure 13 And refer again Figure 4The step of arranging the second sub-mask RL on the upper part of the first sub-mask ML can be the step of arranging each of the plurality of third openings H-ML defined in the first sub-mask ML in correspondence with each of the fourth openings H-RL defined in the second sub-mask RL.

[0099] The step of arranging the second sub-mask RL on top of the first sub-mask ML may include stretching the second sub-mask RL such that the recesses CU-FR of the mask frame FR overlap with the second sub-mask RL and each of the third openings H-ML overlaps with each of the fourth openings H-RL. Stretching the second sub-mask RL may be a step of stretching the second sub-mask RL completely along the first direction DR1 and the second direction DR2 so that the second sub-mask RL overlaps with the entire surface of the mask body MK. Although not illustrated, stretching the second sub-mask RL may be a step of stretching the second sub-mask RL by applying heat. However, this is merely exemplary, and the method of stretching the second sub-mask RL is not limited thereto.

[0100] In order to perform the welding step as a subsequent process, the second sub-mask RL can be stretched to align the second sub-mask RL with the mask body MK, the mask frame FR and the first sub-mask ML.

[0101] Will refer again Figure 5 The steps for arranging a metal rod (S900) on the upper part of the second sub-mask are explained.

[0102] Refer again Figure 5 One embodiment of the mask assembly manufacturing method may include the step of arranging a metal rod W-MS on the upper part of a second sub-mask RL. For example... Figure 13 As shown, the first sub-mask ML and the second sub-mask RL are not arranged inside the recess CU-FR, but a metal rod W-MS is arranged on the upper part of the second sub-mask RL, so that the first sub-mask ML, the second sub-mask RL and the metal rod W-MS can be arranged inside the recess CU-FR.

[0103] Figure 14 This is a schematic diagram illustrating the steps of welding the mask frame, the first sub-mask, the second sub-mask, and the metal rod (S1100).

[0104] Reference Figure 14 The mask frame FR, the first sub-mask ML, the second sub-mask RL, and the metal rod W-MS are welded to the upper part of the metal rod W-MS using a welding unit WU emitting a welding beam WB. Since the second sub-mask RL may be formed using a polymer material, there is a problem of damage during direct welding. Because the mask assembly manufacturing method according to one embodiment includes the metal rod W-MS, the welding strength can be improved compared to welding the upper part of the second sub-mask RL.

[0105] Figure 15 This is a flowchart illustrating in detail the step of arranging a second sub-mask (S700) on top of a first sub-mask in a method for manufacturing a mask assembly according to an embodiment. Figures 16 to 18 It is shown schematically. Figure 15 A flowchart showing each step of the process.

[0106] Reference Figure 15 According to one embodiment of the method for manufacturing a mask assembly, the step of arranging a second sub-mask on top of a first sub-mask (S700) may include the following steps: providing a glass substrate (S710); providing a polymer layer on top of the glass substrate (S720); forming a second sub-mask by patterning the polymer layer to form a fourth opening (S730); arranging the second sub-mask on top of the first sub-mask (S740); and removing the glass substrate (S750).

[0107] Figure 16 This diagram schematically illustrates the steps of forming a second sub-mask (S730) by patterning a polymer layer to form a fourth opening. Figure 17 It is a schematic diagram showing the patterning of polymer layers.

[0108] Reference Figure 16 and Figure 17 The step of forming a second sub-mask by patterning a polymer layer to form a fourth opening (S730) may include irradiating a laser beam LB onto a polymer layer W-RL disposed on the upper part of a glass substrate GL using a laser unit LU. The polymer layer W-RL may include polyimide. Although... Figure 16 Only the step of patterning the polymer layer W-RL using laser etching is shown, but this is merely exemplary and the embodiments are not limited thereto. Although not illustrated, in one embodiment, the step of forming the second sub-mask RL by patterning the polymer layer W-RL (S730) may include the step of patterning the polymer layer W-RL using dry etching.

[0109] Figure 18 This diagram schematically illustrates the step of placing the second sub-mask on top of the first sub-mask (S740). See reference. Figure 18 This may include the step of placing the second sub-mask RL on top of the first sub-mask ML in a manner that exposes the glass substrate GL to the outside (S740). If the step of removing the glass substrate (S750) is performed after the step of placing the second sub-mask on top of the first sub-mask (S740), then as follows... Figure 3 As shown, the second sub-mask RL can be arranged on top of the first sub-mask ML without a glass substrate GL.

[0110] One embodiment can provide a lightweight large mask assembly including a mask body, a first sub-mask disposed on the upper part of the mask body and formed of metal, and a second sub-mask disposed on the upper part of the first sub-mask and formed of polymer.

[0111] One embodiment provides a method for manufacturing a large mask assembly with low weight, including the steps of arranging a first sub-mask formed of metal on the upper part of a mask body and arranging a second sub-mask formed of polymer on the upper part of the first sub-mask.

[0112] While the above description has been made with reference to preferred embodiments of the present invention, it will be understood by those skilled in the art or those with ordinary knowledge of the art that various modifications and alterations can be made to the present invention without departing from the spirit and technical scope of the invention as set forth in the claims.

[0113] Therefore, the technical scope of this invention should not be limited to the contents described in the detailed specification, but should be determined by the scope of the claims.

Claims

1. A mask assembly comprising: a mask frame defining a first opening portion at a center, and including an outer frame portion surrounding the first opening portion and defining at least one recess portion; a mask body arranged corresponding to the first opening portion, and defining a plurality of second opening portions having areas smaller than the first opening portion on a plane; a first sub-mask arranged on an upper portion of the mask body, defining a plurality of third opening portions having areas smaller than each of the second opening portions on a plane on an entire surface, and formed of a metallic substance; a second sub-mask arranged on an upper portion of the first sub-mask, defining a plurality of fourth opening portions on an entire surface, and formed of a high molecular substance; and a welding portion arranged on an upper portion of the second sub-mask inside the at least one recess portion, wherein an inner side surface of the outer frame portion defining the first opening portion and the recess portion are spaced apart from each other by a portion of the mask frame.

2. The mask assembly according to claim 1, wherein the second sub-mask includes polyimide.

3. The mask assembly according to claim 1, wherein a coefficient of thermal expansion of the second sub-mask is 2 ppm / °C or less.

4. The mask assembly according to claim 1, wherein each of the fourth opening portions is defined corresponding to each of the third opening portions.

5. The mask assembly according to claim 1, wherein each of the second opening portions overlaps a plurality of the third opening portions.

6. The mask assembly according to claim 1, wherein the first sub-mask includes: a plurality of first metal lines extending in a first direction and arranged in a second direction perpendicular to the first direction; and a plurality of second metal lines extending in the second direction and arranged in the first direction, wherein each of the first metal lines and each of the second metal lines cross each other.

7. The mask assembly according to claim 6, wherein an up-and-down relationship of each of the first metal lines and the second metal lines alternates, an up-and-down relationship of each of the second metal lines and the first metal lines alternates.

8. The mask assembly according to claim 1, wherein an area of each of the third opening portions is greater than or equal to an area of each of the fourth opening portions on a plane.

9. The mask assembly according to claim 1, wherein a thickness of the first sub-mask is 2 μm or more and 5 μm or less.

10. The mask assembly according to claim 1, wherein a thickness of the second sub-mask is 5 μm or more and 30 μm or less.

11. The mask assembly according to claim 1, wherein a depth of the recess portion in a thickness direction of the outer frame portion is greater than a sum of thicknesses of the first sub-mask, the second sub-mask, and the welding portion.

12. The mask assembly according to claim 1, wherein the recess portion includes a curved portion on a cross section.

13. A mask assembly comprising: a mask frame defining a first opening portion at a center, and including an outer frame portion surrounding the first opening portion and defining at least one recess portion; ​ a mask body arranged corresponding to the first opening portion and defined with a plurality of second opening portions having an area in a plane smaller than the first opening portion; a first sub-mask arranged on an upper portion of the mask body and defined with a plurality of third opening portions having an area in a plane smaller than the second opening portions over an entire surface and formed of a metal substance; a second sub-mask arranged on an upper portion of the first sub-mask and defined with a plurality of fourth opening portions having an area in a plane smaller than the third opening portions over an entire surface and formed of a high molecular substance; and at least one weld portion arranged on an upper portion of the second sub-mask, wherein the outer frame includes: a first portion overlapping the first sub-mask, the second sub-mask, and the weld portion; and a second portion overlapping the first sub-mask and the second sub-mask and not overlapping the weld portion, a thickness of the first portion is smaller than a thickness of the second portion, wherein an inner side surface of the outer frame defining the first opening portion and the recess are spaced apart from each other by a portion of the mask frame.

14. The mask assembly of claim 13, wherein: the at least one recess is a plurality of recesses, and the at least one weld portion is a plurality of weld portions, the plurality of recesses are defined in the first portion as being recessed in a thickness direction, and each of the weld portions overlaps each of the recesses.

15. The mask assembly of claim 13, wherein: the second sub-mask includes polyimide.

16. The mask assembly of claim 13, wherein: the mask frame and the mask body include the same metal.

17. The mask assembly of claim 16, wherein: the metal is invar.

18. A method of manufacturing a mask assembly, comprising the steps of: providing a mask frame defined with a first opening portion at a center and including an outer frame surrounding the first opening portion and defined with a recess; arranging a mask body defined with a plurality of second opening portions having an area in a plane smaller than the first opening portion corresponding to the first opening portion of the mask frame; arranging a first sub-mask defined with a plurality of third opening portions having an area in a plane smaller than the second opening portions over an entire surface on an upper portion of the mask body; arranging a second sub-mask defined with a plurality of fourth opening portions having an area in a plane smaller than the third opening portions over an entire surface on an upper portion of the first sub-mask; arranging a metal rod on the second sub-mask inside the recess; and welding the mask frame, the first sub-mask, the second sub-mask, and the metal rod in a region overlapping the recess, wherein an inner side surface of the outer frame defining the first opening portion and the recess are spaced apart from each other by a portion of the mask frame.

19. The method of manufacturing a mask assembly of claim 18, wherein: the step of arranging the first sub-mask includes the step of: stretching the first sub-mask such that the recess overlaps the first sub-mask.

20. The method of manufacturing a mask assembly of claim 18, wherein: ​ ​ The step of arranging the second sub-mask includes the steps of: stretching the second sub-mask so that the recesses overlap the second sub-mask and each of the third opening portions overlaps each of the fourth opening portions.

21. The method of manufacturing a mask assembly according to claim 18, wherein The step of arranging the second sub-mask on the upper portion of the first sub-mask includes the steps of: providing a glass substrate; providing a polymer layer on an upper portion of the glass substrate; patterning the polymer layer to form the fourth opening portions to form a second sub-mask; and arranging the second sub-mask on the upper portion of the first sub-mask in a manner that exposes the glass substrate to the outside; and removing the exposed glass substrate.

22. The method of manufacturing a mask assembly according to claim 21, wherein The step of forming the second sub-mask includes the steps of patterning the polymer layer by a laser etching method or a dry etching method.

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