Mask assembly and manufacturing method thereof

Abstract

A mask assembly for a thin film process may include: a metal sheet including a mesh-shaped frame region and a plurality of opening forming regions disposed inside the mesh and each forming a plurality of opening portions therein; the mask frame is arranged to correspond to the frame areas at the two ends of the metal sheet, the thickness of the frame areas is larger than that of the opening forming areas, and the thickness of the frame areas is larger than that of the opening forming areas in the thickness direction of the metal sheet. The neutral surface of the metal sheet may be located inside the opening formation region or between a position 50% of the thickness of the metal sheet and the surface of the opening formation region.

Description

Technical Field

[0001] The invention relates to a mask assembly and a method for manufacturing the same. Background Art

[0002] Currently produced organic light-emitting display devices (OLED, Organic Light-Emitting Diode) are widely used as display devices installed in televisions, personal computers (PCs), tablet computers, smart phones, smart watches, and car dashboards. The organic light-emitting display device can be a thin film light-emitting diode whose light-emitting layer is composed of organic compounds.

[0003] Manufacturing an organic light-emitting display device may require a thin film process, in which multiple thin film layers (e.g., electrode layers, organic light-emitting layers, insulating films, etc.) are laminated and / or patterned. The thin film process uses a mask assembly, each mask assembly is equipped with a corresponding pattern, such as chemical vapor deposition (CVD), sputtering, ion plating, or vacuum evaporation.

[0004] In particular, among mask assemblies used in a process of manufacturing an organic light-emitting display device, a fine metal mask assembly may be a mask for laminating a thin film layer in a region corresponding to a pixel.

[0005] The mask assembly as described above may have a structure in which a metal sheet provided with a plurality of opening portions is attached to a mask frame.

[0006] In addition, a fine metal mask assembly for manufacturing a high-resolution display panel may use an ultra-thin metal sheet. However, the ultra-thin metal sheet has weak rigidity, which may cause a problem in the handling of the mask assembly. Summary of the invention

[0007] Technical issues

[0008] The present invention is made to solve the above-mentioned problems of the prior art. One of the purposes of the present invention is to provide a mask assembly and a manufacturing method thereof that can enhance the rigidity of an ultra-thin metal sheet.

[0009] Technical Solution

[0010] According to one aspect of the present invention, a mask assembly is used for a thin film process, which may include: a metal sheet, which includes a grid-shaped frame area and a plurality of opening forming areas, wherein the opening forming areas are arranged inside the grid and each of which forms a plurality of opening portions; and a mask frame, which is configured to correspond to the frame areas at both ends of the metal sheet, wherein the thickness of the frame area is greater than the thickness of the opening forming area, and in the thickness direction of the metal sheet, the neutral plane of the metal sheet may be located inside the opening forming area or between a position of 50% of the thickness of the metal sheet and a surface of the opening forming area.

[0011] In one embodiment of the present invention, in the thickness direction of the frame area, the opening forming area can be connected to one of the upper end and the lower end of the frame area, and in the thickness direction of the metal sheet, the neutral plane of the metal sheet can be located between a position at a distance of 30% of the thickness of the metal sheet from the surface of the opening forming area and the surface of the opening forming area.

[0012] In one embodiment of the present invention, in the thickness direction of the frame area, the opening forming area can be connected between the upper end and the lower end of the frame area, and in the thickness direction of the metal sheet, the neutral plane of the metal sheet can be located inside the opening forming area.

[0013] In one embodiment of the present invention, it may further include at least one dummy area, which is arranged inside the grid, has a thickness that is the same as that of the frame area, and does not form the opening portion, wherein the opening forming area and the dummy area are arranged in a matrix form, and the opening forming area and the dummy area can be arranged alternately.

[0014] In an embodiment of the present invention, the opening forming regions and the dummy regions may be arranged alternately with each other in each row and each column.

[0015] In an embodiment of the present invention, the opening forming region may be arranged in one of the adjacent rows, and the dummy region may be arranged in the other row.

[0016] In one embodiment of the present invention, the thickness of the frame region may be 8um to 100um, and the thickness of the opening forming region may be 0.5um to 8um.

[0017] In one embodiment of the present invention, the thickness of the opening forming region may be 2 um to 6 um.

[0018] According to an aspect of the present invention, a method for manufacturing a mask assembly is provided for a thin film process, which may include: preparing a metal sheet, wherein the metal sheet is divided into a grid-shaped frame area and an opening forming area arranged inside the grid; removing part of the thickness of the opening forming area; forming a plurality of openings in the opening forming area; stretching the metal sheet with the openings formed therein; and arranging a mask frame corresponding to the frame area at both ends of the metal sheet, wherein the thickness of the frame area is greater than the thickness of the opening forming area, and in the thickness direction of the metal sheet, the neutral plane of the metal sheet may be located inside the opening forming area or between a position at 50% of the thickness of the metal sheet and a surface of the opening forming area.

[0019] In one embodiment of the present invention, in the thickness direction of the frame area, at one of the upper end and the lower end where the opening forming area is connected to the frame area, in the thickness direction of the metal sheet, the neutral plane of the metal sheet may be located between a position at a distance of 30% of the thickness of the metal sheet from the surface of the opening forming area and the surface of the opening forming area, and the step of removing part of the thickness of the opening forming area may include: arranging a photosensitive film on one side of the metal sheet; exposing and developing the photosensitive film to expose the opening forming area; and removing part of the thickness of the opening forming area by etching the photosensitive film that exposes the opening forming area as a mask.

[0020] In one embodiment of the present invention, in the thickness direction of the frame area, the opening forming area can be connected between the upper end and the lower end of the frame area, and in the thickness direction of the metal sheet, the neutral plane of the metal sheet can be located inside the opening forming area, and the step of removing part of the thickness of the opening forming area may include: a first process, which removes part of the thickness of the opening forming area through one side of the metal sheet; and a second process, which removes part of the thickness of the opening forming area through the other side of the metal sheet, wherein the first process and the second process include: forming a photosensitive film on the metal sheet, the photosensitive film exposing the opening forming area; and removing part of the thickness of the opening forming area by etching the photosensitive film exposing the opening forming area as a mask.

[0021] Beneficial Effects

[0022] The mask assembly and the manufacturing method thereof according to the present invention can enhance the rigidity of the ultra-thin metal sheet.

[0023] Therefore, handling of the mask assembly can be facilitated. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1is a cross-sectional view for describing a mask assembly according to an embodiment of the present invention.

[0025] Figure 2 is a cross-sectional view for describing the formation of a thin film using a mask assembly according to an embodiment of the present invention.

[0026] Figure 3 Is used to describe Figure 1 and Figure 2 A plan view of the mask assembly shown.

[0027] Figures 4 to 6 is along Figure 3 The cross-sectional view along line II' is shown.

[0028] Figures 7 to 10 is a cross-sectional view for describing a method for manufacturing a mask assembly according to an embodiment of the present invention.

[0029] Fig.11 is a diagram for describing a method of applying a tensile force to a metal sheet.

[0030] Fig. 12A , Fig.13A as well as Fig.14A is used to describe Figure 4 and Figure 6 Graph showing the deflection of the metal sheet when tensile forces of 0N, 10N and 30N are applied.

[0031] Fig. 12B , Fig. 13B as well as Fig. 14B is used to describe Figure 5 Graph showing the deflection of the metal sheet when tensile forces of 0N, 10N and 30N are applied.

[0032] Fig.11 is a diagram for describing a method of applying a tensile force to a metal sheet.

[0033] Fig. 12A , Fig.13A as well as Fig.14A is used to describe Figure 4 and Figure 6 Graph showing the deflection of the metal sheet when tensile forces of 0N, 10N and 30N are applied.

[0034] Fig. 12B , Fig. 13B as well as Fig. 14B is used to describe Figure 5 Graph showing the deflection of the metal sheet when tensile forces of 0N, 10N and 30N are applied.

[0035] Fig.15A , Fig.16A as well as Fig.17A is used to describe Figure 4 and Figure 6 The graph shows the change in internal stress when tensile forces of 0N, 10N and 30N are applied to the metal sheet.

[0036] Fig. 15B , Fig. 16B as well as Fig. 17B is used to describe Figure 5 The graph shows the change in internal stress when tensile forces of 0N, 10N and 30N are applied to the metal sheet.

[0037] Fig.18 FIG. 1 is a diagram for describing the configuration of an opening forming region in a metal sheet according to an embodiment of the present invention.

[0038] Fig.19A , Fig. 20A as well as Fig.21A Is used to describe Fig.18 Figure 1. Diagram of the configuration of the opening forming area in which the metal sheet moves.

[0039] Fig.19B , Fig. 20B as well as Fig.21B is through according to Fig.18 FIG. 1 is a diagram of a deposition area in which a metal sheet is moved to form an opening configuration to describe a deposition area for a deposited thin film.

[0040] Fig. 22 FIG. 1 is a diagram for describing the configuration of an opening forming region in a metal sheet according to an embodiment of the present invention.

[0041] Fig.23A Is used to describe Fig. 22 Figure 1. Diagram of the configuration of the opening forming area in which the metal sheet moves.

[0042] Fig. 23B is through according to Fig. 22 FIG. 1 is a diagram of a deposition area in which a metal sheet is moved to form an opening configuration to describe a deposition area for a deposited thin film. DETAILED DESCRIPTION

[0043] The objects, advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the accompanying drawings. In this specification, when reference numerals are assigned to the constituent elements of each drawing, the same reference numerals are assigned to the same constituent elements even if they are shown on different drawings. In addition, when a detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, its detailed description will be omitted.

[0044] In addition, the drawings are used to help understand the embodiments disclosed in this specification, the technical concept disclosed in this specification is not limited to the drawings, and the present invention includes all modifications, equivalents and substitutes to the concept and technical scope of the present invention.

[0045] In addition, terms such as first, second, etc. including ordinal numbers may be used to describe various components, but the components are not limited to the above terms. The above terms are only used to distinguish one component from other components.

[0046] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the accompanying drawings.

[0047] Figure 1 is a cross-sectional view for describing a mask assembly according to an embodiment of the present invention.

[0048] See also Figure 1 The mask assembly MA according to an embodiment of the present invention may be a fine metal mask (FMM) and may be a mask for forming a thin film layer on a pixel of a unit display panel. In particular, the mask assembly MA according to an embodiment of the present invention may be used as a deposition mask for manufacturing a display panel with extremely high resolution (e.g., a display panel for augmented reality or virtual reality).

[0049] The mask assembly MA as described above may include a mask frame 100 and a metal sheet 200 .

[0050] The mask frame 100 is arranged on one side of the metal sheet 200 to support the metal sheet 200. Figure 1 As shown, the mask frame 100 can be arranged on the upper surface of the metal sheet 200, but is not limited thereto. For example, the mask frame 100 can be arranged on the lower surface of the metal sheet 200. This is related to the deposition direction of the deposition material, and the mask frame 100 can be provided on the surface arranged in the deposition direction of the metal sheet 200.

[0051] The mask frame 100 may be made of materials such as SUS300 series, SUS400 series, Ni alloy (Invar), etc. This is to minimize deformation of the mask frame 100 in a high temperature environment of various deposition processes.

[0052] The metal sheet 200 may include a plurality of opening portions 210 provided to correspond to regions where a thin film pattern (eg, an organic film pattern) is formed.

[0053] The metal sheet 200 may be made of materials such as SUS300 series, SUS400 series, Ni alloy (Invar), etc. This is to minimize deformation of the metal sheet 200 in a high temperature environment of various deposition processes.

[0054] In addition, the mask frame 100 and the metal sheet 200 may be made of metal materials with very small thermal expansion coefficients, such as Invar. If the mask frame 100 and the metal sheet 200 are made of materials with large thermal expansion coefficients, the value of the opening 210 may change, making it difficult to perform accurate thin film deposition.

[0055] In addition, the mask frame 100 and the metal sheet 200 may be composed of materials with the same thermal expansion coefficient. This is to prevent the mask frame 100 and the metal sheet 200 from deforming due to different expansion rates caused by the difference in thermal expansion coefficients in the high-temperature process. In particular, the deposition process using the mask assembly MA is mostly performed at high temperatures. If the difference in thermal expansion coefficients between the mask frame 100 and the metal sheet 200 is large, the mask assembly MA will deform due to the difference in thermal expansion coefficients itself.

[0056] In addition, the metal sheet 200 should be evenly attached to the substrate, and thus needs to be kept flat. To this end, the thickness of the mask frame 100 may be greater than the thickness of the metal sheet 200 .

[0057] In addition, in order to prevent the central portion of the metal sheet 200 from being bent, the metal sheet may be fixed to the mask frame 100 by spot welding or the like in a state in which the central portions of four sides extend outward.

[0058] Figure 2 1 is a cross-sectional view for describing the formation of a thin film using a mask assembly according to an embodiment of the present invention. Figure 2 In the embodiment, an example of forming an organic film pattern OL using a mask assembly MA is used for description.

[0059] See also Figure 2 , a mask assembly MA is arranged on a substrate SUB. The substrate SUB may be a mother substrate for forming a plurality of unit display panels. That is, the substrate SUB may be in a state where a region capable of forming a unit display panel is preset.

[0060] In addition, although not shown, a thin film transistor, a planarization layer, a first electrode of an organic light emitting device, a pixel definition film, etc. may be formed in advance on a unit display panel formation region in the substrate SUB.

[0061] The mask assembly MA may include a mask frame 100 and a metal sheet 200. The opening portion 210 of the metal sheet 200 may be configured to correspond to a formation region of the organic film pattern OL, wherein the formation region of the organic film pattern OL may correspond to a pixel region of the display panel.

[0062] After the mask assembly MA is disposed on the substrate SUB, an organic film pattern OL may be formed by depositing an organic substance, wherein the organic film pattern OL may be formed on the substrate SUB through the opening 210 and may be a light emitting layer of a display device.

[0063] In addition, in one embodiment of the present invention, the use of the mask assembly MA to form the organic film pattern OL is exemplified, but the invention is not limited thereto. For example, in one embodiment of the present invention, the mask assembly MA can be used to deposit a substance that can be formed on each pixel by a deposition process such as PVD, such as a metal film or an inorganic film.

[0064] In addition, Figure 2 In the embodiment, the deposition process is performed by placing the mask assembly MA on the substrate SUB, but the present invention is not limited thereto. For example, the mask assembly MA may be located below the substrate (where the deposition surface on which the thin film may be formed faces downward), and the deposition material may rise and pass through the opening 210 to form a thin film on the deposition surface of the substrate SUB.

[0065] In addition, Figure 2 In the embodiment, the mask assembly MA and the substrate SUB are arranged separately, but the present invention is not limited thereto. For example, the deposition process can be performed in a state where the mask assembly MA and the substrate SUB are attached to each other.

[0066] See below Figures 3 to 6 The above-mentioned mask assembly MA is described in further detail.

[0067] Figure 3 Is used to describe Figure 1 and Figure 2 A plan view of the mask assembly shown, Figures 4 to 6 is along Figure 3 The cross-sectional view along line II' is shown.

[0068] See also Figure 3 and Figure 6 , a mask assembly MA according to an embodiment of the present invention may include a mask frame 100 and a metal sheet 200 .

[0069] The mask frame 100 is arranged on one side of the metal sheet 200 to support the metal sheet 200. The mask frame 100 is arranged on one side of the metal sheet 200 to support the metal sheet 200. Figure 3 As shown, the mask frame 100 can be arranged on the upper surface of the metal sheet 200, but is not limited thereto. For example, the mask frame 100 can be arranged on the lower surface of the metal sheet 200. This is related to the deposition direction of the deposition material, and the mask frame 100 can be provided on the surface arranged in the deposition direction of the metal sheet 200.

[0070] The mask frame 100 may be made of materials such as SUS300 series, SUS400 series, Ni alloy (Invar), etc. This is to minimize deformation of the mask frame 100 in a high temperature environment of various deposition processes.

[0071] The metal sheet 200 may include a plurality of openings 210 provided to correspond to regions where thin film patterns (eg, organic film patterns) are formed. The metal sheet 200 is combined with the mask frame 100 in a stretched state, and the mask frame 100 may fix the stretched metal sheet 200.

[0072] The metal sheet 200 as described above may include a frame region 220F and an opening forming region 2200 .

[0073] The frame region 220F is a region for maintaining the rigidity of the metal sheet 200, and its thickness may be greater than the thickness of the opening forming region 2200. The thickness of the frame region 220F may be 8 um to 100 um.

[0074] The frame region 220F is used to prevent the rigidity of the metal sheet 200 from decreasing due to the extremely thin opening forming region 220O. The frame region 220F can make the metal sheet 200 according to an embodiment of the present invention have the same rigidity as a common thin metal sheet.

[0075] In addition, the frame area 220F may have a grid shape including a plurality of inner areas.

[0076] The opening forming area 220O may be arranged corresponding to the inner area formed by the frame area 220F of the grid shape. That is, the opening forming area 220O may be an area surrounded by the frame area 220F, and a plurality of opening forming areas 220O may be provided in the metal sheet 200. The number of the opening forming areas 220O may correspond to the number of unit display panels generated on one motherboard. That is, when N (N is a natural number) unit display panels are produced using one motherboard, the metal sheet 200 may include N opening forming areas 220O.

[0077] The thickness of the opening forming region 220O may be smaller than the thickness of the frame region 220F. For example, the ratio of the thickness of the opening forming region 220O to the thickness of the frame region 220F may be 1 / 200 to 1 / 1. Preferably, the ratio of the thickness of the opening forming region 220O to the thickness of the frame region 220F may be 1 / 50 to 3 / 4.

[0078] In addition, the thickness of the opening formation region 220O may be 0.5 um to 8 um. Preferably, the thickness of the opening formation region 220O may be 2 um to 6 um.

[0079] In the thickness direction of the frame region 220F, the opening forming region 220O may be connected to one of the lower end, the middle end, and the upper end of the frame region 220F, wherein the lower end, the middle end, and the upper end may be relative distances from the ground.

[0080] For example, Figure 4 As shown, the opening forming region 220O may be connected to the lower end of the frame region 220F. Due to the difference in thickness between the frame region 220F and the opening forming region 220O, the opening forming region 220O may be provided with an upper concave portion, which may be arranged above the metal sheet 200.

[0081] In addition, if Figure 6 As shown, the opening forming region 220O may be connected to the upper end of the frame region 220F. Due to the difference in thickness between the frame region 220F and the opening forming region 220O, the opening forming region 220O may be provided with a concave portion, which may be arranged below the metal sheet 200.

[0082] Since the thickness of the opening forming region 220O is smaller than the thickness of the frame region 220F, the neutral plane NP of the metal sheet 200 can be arranged adjacent to the opening forming region 220O on the metal sheet 200 rather than in the center of the metal sheet 200. That is, Figure 4 and Figure 6 The neutral plane NP of the metal sheet 200 shown may be located between a position of 50% of the thickness of the metal sheet 200 in the thickness direction of the metal sheet 200 and a surface of the opening forming region 220O.

[0083] In particular, the closer the neutral plane NP of the metal sheet 200 is to the opening forming region 220O, the more the rigidity of the metal sheet 200 is improved. For example, the neutral plane NP of the metal sheet 200 may be located between a position at a distance of 30% of the thickness of the metal sheet 200 from the surface of the opening forming region 220O in the thickness direction of the metal sheet 200 and the surface of the opening forming region 220O.

[0084] like Figure 5 As shown, the opening forming area 220O can be connected to the middle end of the frame area 220F, that is, between the upper end and the lower end. Wherein, due to the difference in thickness between the frame area 220F and the opening forming area 220O, the opening forming area 220O can be equipped with an upper concave portion and a lower concave portion, the upper concave portion is arranged above the metal sheet 200, and the lower concave portion is arranged below the metal sheet 200. That is, the upper and lower parts of the metal sheet 200 of the opening forming area 220O can be equipped with concave portions.

[0085] Since the opening forming region 220O is located between the upper end and the lower end of the frame region 220F, the neutral plane NP of the metal sheet 200 may be located within the opening forming region 220O in the thickness direction of the metal sheet 200. Therefore, the rigidity of the metal sheet 200 provided in the mask assembly MA according to an embodiment of the present invention is improved.

[0086] In the mask assembly MA as described above, the metal sheet 200 may include the frame region 220F and the opening forming region 220O, and the frame region 220F has a structure with enhanced rigidity due to being thicker than the opening forming region 220O. Therefore, the mask assembly MA can be easily handled.

[0087] See below Figures 7 to 10 A method for manufacturing the above-mentioned mask assembly MA is described in detail.

[0088] Figures 7 to 10 is a cross-sectional view for describing a method for manufacturing a mask assembly according to an embodiment of the present invention.

[0089] First, see Figure 7 , prepare a thin metal sheet 200. The thickness of the metal sheet 200 may be 8um to 100um.

[0090] In addition, the metal sheet 200 may include a frame region 220F and an opening forming region 2200. The frame region 220F is in a grid shape with an inner region, and the opening forming region 220O may be arranged corresponding to the inner region formed by the frame region 220F. That is, the frame region 220F may have a shape surrounding the opening forming region 220O.

[0091] The metal sheet 200 may be made of materials such as SUS300 series, SUS400 series, and Ni alloy (Invar).

[0092] refer to Figure 8 , a portion of the thickness of the opening forming region 220O of the metal sheet 200 may be removed. Thus, the thickness of the opening forming region 220O of the metal sheet 200 may be smaller than the thickness of the frame region 220F.

[0093] The mask assembly MA according to an embodiment of the present invention is a fine metal mask assembly (FMMAssembly) for manufacturing a high-resolution display panel of an augmented reality (AR) display panel or a virtual reality (VR) display panel, so the remaining thickness of the opening forming area 2200 may be 0.5um to 8um. Preferably, the remaining thickness of the opening forming area 2200 may be 1um to 4um.

[0094] For example, the ratio of the thickness of the opening forming region 2200 to the thickness of the frame region 220F may be 1 / 1 to 1 / 200.

[0095] In addition, a portion of the thickness of the opening forming area 2200 can be removed by various methods. For example, a photosensitive film PRF such as a dry film resist (DFR) can be arranged on one side of the metal sheet 200. Then, the opening forming area 2200 can be exposed by exposing and developing the photosensitive film PRF. The opening forming area 2200 is wet-etched or dry-etched by using the photosensitive film PRF that exposes the opening forming area 2200 as a mask. A portion of the thickness of the opening forming area 2200 is removed by wet etching or dry etching, thereby making it possible to produce an opening. Figure 4 and Figure 6 The metal sheet 200 is shown.

[0096] In addition, the photosensitive film PRF is used as an example according to an embodiment of the present invention, but is not limited thereto. For example, instead of the photosensitive film PRF, the same process may be performed by coating a photosensitive material on the metal sheet 200 .

[0097] In addition, instead of the above-mentioned photosensitive film PRF, a polymer film (e.g., a polyimide film) is arranged on one side of the metal sheet 200 to expose the opening forming area 2200 by patterning, and a laser is irradiated on the opening forming area 2200. When the laser is irradiated to the opening forming area 2200, part of the thickness of the opening forming area 2200 is removed, such as LLO (Laser-Lift-Off), thereby making it possible to manufacture a film such as Figure 4 and Figure 6 The metal sheet 200 is shown.

[0098] In addition, after performing a first process of removing a portion of the thickness of the opening forming region 2200 through one side of the metal sheet 200, a second process of removing a portion of the thickness of the opening forming region 2200 through the other side of the metal sheet 200 is performed, thereby manufacturing an inlet and outlet Figure 5 The metal sheet 200 shown. The first process may be a process of forming a photosensitive film PRF or a polymer film on one side of the metal sheet 200 and removing a portion of the thickness of the opening forming area 2200 by etching or laser, wherein the photosensitive film PRF or the polymer film exposes the opening forming area 2200. The second process may be a process of removing a portion of the thickness of the opening forming area 2200 by etching or laser after arranging the photosensitive film PRF or the polymer film on the other side of the metal sheet 200.

[0099] See also Fig. 9, the photosensitive film PRF can be removed after removing part of the thickness of the opening forming area 2200, and the opening portion 210 for depositing a thin film can be formed by processing the opening forming area 2200. Among them, the opening portion 210 can be formed by laser. Specifically, the laser used to form the opening portion 210 can be an ultra-short pulsed laser, such as a picosecond laser or a femtosecond laser.

[0100] Among ultrashort pulse lasers, the pulse duration of a femtosecond laser is extremely short, about femtoseconds (10 -15 Femtosecond lasers are a type of laser processing equipment used in recent years, and are used in many fields such as displays, printed electronic circuit boards, biology and medicine, semiconductors, solar cells, etc., and have gradually developed from existing expensive equipment to equipment that can be used in the ultra-precision processing industry.

[0101] If the above-mentioned femtosecond laser is used for the opening 210 of the metal sheet 200, the surface of the processed object does not melt and directly vaporizes into particles, so the processing is completed before the heat is transferred to the surroundings. Therefore, the processing method using the femtosecond laser can process in a manner that does not generate heat to the processed object. Therefore, when using the femtosecond laser, a fine opening 210 can be formed without causing unnecessary damage to the opening 210 of the metal sheet 200.

[0102] In one embodiment of the present invention, the mask assembly MA is a fine metal mask assembly, and thus the opening 210 may correspond to a pixel of a unit display panel.

[0103] The opening 210 may be deformed in shape or moved in position due to the subsequent stretching of the metal sheet 200. Therefore, the opening 210 formed by laser light may be formed in consideration of the deformation caused by the subsequent stretching of the metal sheet 200.

[0104] As described in further detail below, the opening 210 may be formed as follows.

[0105] First, a first opening region for forming the opening 210 may be set in the metal sheet 200. After the first opening region is set, the deformation amount of the first opening region due to stretching may be calculated. The deformation amount may be the deformation amount of the first opening region caused by the stretching of the metal sheet 200 and the positional movement thereof.

[0106] Then, the first opening region may be modified by using the deformation amount, thereby setting the second opening region. After the second opening region is set, the opening 210 may be formed by patterning the second opening region using a laser.

[0107] After the opening portion 210 is formed, clamps (not shown) are provided at the frame regions 220F at both ends of the metal sheet 200 , and the metal sheet 200 may be stretched by moving the clamps.

[0108] The opening 210 of the metal sheet 200 stretched by the clamp movement can be arranged at a position corresponding to a pixel of a unit display panel. That is, as the metal sheet 200 is stretched, the shape and position of the opening 210 are modified, thereby being arranged at a position corresponding to a pixel of a unit display panel.

[0109] See also Fig.10 After the metal sheet 200 is stretched, a mask frame 100 may be disposed on one side of the metal sheet 200 (eg, the upper surface of the metal sheet 200 ).

[0110] The mask frame 100 can fix the metal sheet 200 in a stretched state.

[0111] The mask frame 100 is arranged corresponding to the frame area 220F at both ends of the metal sheet 200 and can support the metal sheet 200. The mask frame 100 can be made of SUS300 series, SUS400 series, Ni alloy (Invar), etc. This is to minimize the deformation of the mask frame 100 in the high temperature environment of various deposition processes.

[0112] See below Figure 11 to Figure 1 7. Describe the change in deflection of the metal sheet after stretching and the change in stress inside the metal sheet.

[0113] Fig.11 is a diagram used to describe a method of applying a tensile force to a metal sheet. Fig. 12A , Fig.13A as well as Fig.14A is used to describe Figure 4 and Figure 6 The figure shows the deflection of the metal sheet when 0N, 10N and 30N tensile forces are applied. Fig. 12B , Fig. 13B as well as Fig. 14B is used to describe Figure 5 The figure shows the deflection of the metal sheet when 0N, 10N and 30N tensile forces are applied. Fig.15A , Fig.16A as well as Fig.17A is used to describe Figure 4 and Figure 6The graph shows the change of internal stress when 0N, 10N and 30N tensile forces are applied to the metal sheet. Fig. 15B , Fig. 16B as well as Fig. 17B is used to describe Figure 5 The graph shows the change in internal stress when tensile forces of 0N, 10N and 30N are applied to the metal sheet.

[0114] First, see Fig.11 , a metal sheet 200 having a rectangular shape, a horizontal length of 200mm, a vertical length of 200mm, a thickness of 40um in the frame area 220F, and a thickness of 5um in the opening forming area 2200 is applied with tensile force in the horizontal and vertical directions, thereby observing the stress according to the deflection of the metal sheet 200 and the tensile force inside the metal sheet 200. Among them, the opening forming area 2200 can be provided in the center of the metal sheet 200, and has a rectangular shape with a horizontal length of 50mm and a vertical length of 50mm. In addition, the acceptable deflection of the metal sheet 200 having the above shape can be within 300μm, and the acceptable yield strength can be within 530MPa.

[0115] like Fig. 12A , Fig. 12B , Fig.13A , Fig. 13B , Fig.14A as well as Fig. 14B As shown, the deflection of the metal sheet 200 decreases with the increase of the tensile force, and is within 300um. In particular, it can be seen that when the tensile force of 10N and 30N is applied to the metal sheet 200, the deflection is greatly reduced compared with when the tensile force of 0N is applied to the metal sheet 200.

[0116] In addition, it can be seen that when the same tensile force is applied to the metal sheet 200, compared with Figure 4 and Figure 6 The deflection of the metal sheet 200 shown, as Figure 5 The metal sheet 200 is shown to have a small deflection.

[0117] Furthermore, when a tensile force is applied to the metal sheet 200 , the metal sheet 200 may be prevented from being flexed, but stress (eg, von-Mises Stress) may be concentrated at the corners of the opening forming area 2200 at the boundary between the frame area 220F and the opening forming area 2200 .

[0118] In particular, since the equivalent stress is concentrated at the corners of the opening forming area 2200, the tensile force applied to the metal sheet 200 should be limited to generate an amount less than the yield strength acceptable to the equivalent stress occurring locally.

[0119] like Fig.15A , Fig. 15B , Fig.16A , Fig. 16B , Fig.17A , Fig. 17B As shown, it can be seen that the more the tensile force of the metal sheet 200 increases, the more the concentrated equivalent stress (von-Mises Stress) increases, but they are all less than or equal to 530MPa. However, it can be seen that when a tensile force of 0N is applied to the metal sheet 200, the stress may be concentrated in the center of the outer periphery of the metal sheet 200, but when a tensile force of 10N and 30N is applied to the metal sheet 200, the stress is concentrated at the boundary of the frame area 220F and the opening forming area 2200. In particular, it can be seen that when a tensile force of 10N and 30N is applied to the metal sheet 200, the stress is concentrated at the corners of the opening forming area 2200 at the boundary of the frame area 220F and the opening forming area 2200.

[0120] In addition, it can be seen that when the same tensile force is applied to the metal sheet 200, compared with Figure 4 and Figure 6 The magnitude of the local concentrated equivalent stress in the metal sheet 200 shown is locally concentrated to Figure 5 The magnitude of the equivalent stress within the metal sheet 200 is shown to be greater.

[0121] Fig.18 is a diagram for describing the configuration of an opening forming region in a metal sheet according to an embodiment of the present invention, Fig.19A , Fig. 20A as well as Fig.21A Is used to describe Fig.18 Figure 1 shows the configuration of the openings formed by the movement of the metal sheet. Fig.19B , Fig. 20B as well as Fig.21B is through according to Fig.18 FIG. 1 is a diagram of a deposition area in which a metal sheet is moved to form an opening configuration to describe a deposition area for a deposited thin film.

[0122] See also Fig.18 , 19A , 19B, 20A, 20B, 21A and 21B, the metal sheet 200 may have a shape corresponding to the mother substrate MS for producing a unit display panel.

[0123] The metal sheet 200 may include a frame region 220F in a grid shape, an opening forming region 2200 located in an inner region of the grid, and a dummy region 220D, wherein the opening forming region 2200 and the dummy region 220D may be arranged in a matrix shape.

[0124] The opening forming region 2200 is a region where the opening portion 210 corresponding to the pixel of the unit display panel is formed, and the dummy region 220D may be a region where the opening portion 210 is not formed. The thickness of the dummy region 220D may be the same as the thickness of the frame region 220F. That is, the dummy region 220D may be an inner region formed by the grid-shaped frame region 220F, and a region where a portion of the thickness of the metal sheet 200 is not removed during the formation of the opening forming region 2200.

[0125] Therefore, the metal sheet 200 including the dummy region 220D may have higher rigidity than the metal sheet 200 not including the dummy region 220D and including only the opening forming region 2200 .

[0126] The opening forming regions 2200 and the dummy regions 220D may be arranged alternately. For example, the opening forming regions 2200 and the dummy regions 220D may be arranged alternately with each other in each row and each column.

[0127] The following are the Fig.18 A thin film deposition method using the mask assembly MA of the metal sheet 200 is described.

[0128] First, equip Fig.18 The mask assembly MA of the metal sheet 200 is arranged on the motherboard MS, and the first thin film deposition process is performed. The deposition area DR where the thin film is formed by the first thin film deposition process can be arranged to correspond to the opening formation area 2200. In addition, the area corresponding to the dummy area 220D can be a non-deposition area NDR. Among them, the deposition area DR can be an area on the motherboard MS where a unit display panel is formed.

[0129] Like the configuration of the opening forming region 2200 and the dummy region 220D of the metal sheet 200 , the deposition regions DR and the non-deposition regions NDR formed by the first thin film deposition process may be alternately arranged with each other in rows and columns.

[0130] After performing the first thin film deposition process, the mask assembly MA is moved to the first position. The first position movement is performed within the plane of the metal sheet 200, and can be performed in one direction of the left direction, the right direction, the upper direction, and the lower direction, for example, the left direction. Due to the first position movement of the mask assembly MA, the opening forming area 2200 can correspond to a portion of the non-deposition area NDR.

[0131] After the mask assembly MA is moved to the first position, a second thin film deposition process is performed. The deposition region DR formed by the second thin film deposition process may be arranged to correspond to the opening formation region 2200 moved to the first position. The deposition region DR and the non-deposition region NDR formed by the first thin film deposition process and the second thin film deposition process may be arranged as shown in FIG. Fig.19B Arrange as shown.

[0132] After performing the second thin film deposition process, the mask assembly MA is moved to the second position. The second position movement is performed within the plane of the metal sheet 200, and can be performed in one direction of the left direction, the right direction, the upper direction, and the lower direction, for example, the lower direction. Due to the second position movement of the mask assembly MA, the opening forming area 2200 can correspond to the remaining part of the non-deposition area NDR.

[0133] After the mask assembly MA is moved to the second position, a third thin film deposition process is performed. The deposition region DR formed by the third thin film deposition process may be arranged to correspond to the opening formation region 2200 moved to the second position. The deposition region DR and the non-deposition region NDR formed by the first thin film deposition process to the third thin film deposition process may be arranged as shown in FIG. Fig. 20B Arrange as shown.

[0134] After performing the third thin film deposition process, the mask assembly MA is moved to the third position. The third position movement is performed within the plane of the metal sheet 200, and can be performed in one direction of the left direction, the right direction, the upper direction, and the lower direction, for example, the right direction. Due to the third position movement of the mask assembly MA, the opening forming area 2200 can correspond to the remaining non-deposition area NDR.

[0135] After the mask assembly MA is moved to the third position, a fourth thin film deposition process is performed. The deposition region DR formed by the fourth thin film deposition process may be arranged to correspond to the opening formation region 2200 moved to the third position. In the fourth thin film deposition process, the opening formation region 2200 corresponds to the non-deposition region NDR remaining after the first thin film deposition process to the third thin film deposition process, so after the fourth thin film deposition process, the non-deposition region NDR may not exist on the mother substrate MS.

[0136] As described above, the thin film deposition method using the mask assembly MA includes the first thin film deposition process to the fourth thin film deposition process, whereby a deposition area DR where a thin film is deposited can be formed on the motherboard MS, wherein the mask assembly MA has a structure in which the opening forming area 2200 and the dummy area 220D are alternately arranged in each row and each column. The position of the opening forming area 2200 moves in each thin film deposition process, so through the first thin film deposition process to the fourth thin film deposition process, a thin film can be formed in each area where a unit display panel is formed in the motherboard MS.

[0137] Fig. 22 is a diagram for describing the configuration of an opening forming region in a metal sheet according to an embodiment of the present invention, Fig.23A Is used to describe Fig. 22 Figure 1 shows the configuration of the openings formed by the movement of the metal sheet. Fig. 23B is through according to Fig. 22 FIG. 1 is a diagram of a deposition area in which a metal sheet is moved to form an opening configuration to describe a deposition area for a deposited thin film.

[0138] See also Fig. 22 , Fig.23A as well as Fig. 23B The metal sheet 200 may include a frame region 220F in a grid shape, an opening forming region 2200 and a dummy region 220D arranged in an inner region of the grid, wherein the opening forming region 2200 and the dummy region 220D may be arranged in a matrix shape.

[0139] The opening forming region 2200 is a region where the opening 210 corresponding to the pixel of the unit display panel is formed, and the dummy region 220D may be a region where no opening 210 is formed. The thickness of the dummy region 220D may be the same as that of the frame region 220F.

[0140] Only the opening forming region 2200 may be arranged in one of the adjacent rows, and only the dummy region 220D may be arranged in the other row. That is, the row where the opening forming region 2200 is arranged and the row where the dummy region 220D is arranged may be arranged alternately.

[0141] The following are the Fig. 22 A thin film deposition method using the mask assembly MA of the metal sheet 200 is described.

[0142] First, equip Figure 2 The mask assembly MA of the metal sheet 200 shown is arranged on the motherboard MS, and the first thin film deposition process is performed. The deposition area DR where the thin film is formed by the first thin film deposition process can be arranged to correspond to the opening forming area 2200. In addition, the area corresponding to the dummy area 220D can be a non-deposition area NDR. Therefore, as in the configuration of the opening forming area 2200 and the dummy area 220D, the row where the deposition area DR is arranged and the row where the non-deposition area NDR is arranged can be arranged alternately. That is, the deposition area DR can be formed on one of the rows adjacent to each other, and the non-deposition area NDR can be arranged on the other row.

[0143] After performing the first thin film deposition process, the position of the mask assembly MA is moved. The position movement of the mask assembly MA is performed within the plane of the metal sheet 200, and may be performed in one of the upper and lower directions, for example, the lower direction. Due to the position movement of the mask assembly MA, the opening forming area 2200 may correspond to the non-deposition area NDR of the mother substrate MS.

[0144] After the position of the mask assembly MA is moved, a second thin film deposition process is performed. The deposition area DR formed by the second thin film deposition process can be arranged to correspond to the opening formation area 2200 moved in position. If the second thin film deposition process is performed, the area forming the unit display panel in the motherboard MS can be the deposition area DR, and there is no non-deposition area NDR.

[0145] As described above, the thin film deposition method using the mask assembly MA includes a first thin film deposition process and a second thin film deposition process, whereby a deposition region DR where a thin film is deposited can be formed on the motherboard MS, wherein the mask assembly MA has a structure in which a row in which the opening forming region 2200 is arranged and a row in which the dummy region 220D is arranged are alternately arranged. The position of the opening forming region 2200 moves in each thin film deposition process, so that through the first thin film deposition process and the second thin film deposition process, a thin film can be formed in all regions in which a unit display panel is formed in the motherboard MS.

[0146] The present invention is not limited to the above embodiments, but also includes a combination of at least two of the above embodiments as a new embodiment or a combination of at least one of the above embodiments and a known technology.

[0147] The present invention is described in detail above through specific embodiments. These embodiments are used to describe the present invention in detail, but the present invention is not limited thereto. The present invention can be modified or improved by those skilled in the art within the scope of the technical concept.

[0148] Simple modifications or changes to the present invention are all within the scope of the present invention, and the specific protection scope of the present invention becomes clear from the attached claims.

Claims

1. A mask assembly for thin film processing, comprising: a metal sheet including a frame region in a grid shape and a plurality of opening forming regions, the opening forming regions being arranged inside the grid and each of which has a plurality of opening portions formed therein; as well as a mask frame, which is arranged corresponding to the frame areas at both ends of the metal sheet, The thickness of the frame region is greater than the thickness of the opening forming region. In the thickness direction of the metal sheet, the neutral plane of the metal sheet is located inside the opening forming region or between a position of 50% of the thickness of the metal sheet and a surface of the opening forming region.

2. The mask assembly according to claim 1, wherein: The opening forming region is connected to one of an upper end and a lower end of the frame region in a thickness direction of the frame region, In the thickness direction of the metal sheet, the neutral plane of the metal sheet is located between a position at a distance of 30% of the thickness of the metal sheet from the surface of the opening forming region and the surface of the opening forming region.

3. The mask assembly according to claim 1, wherein: The opening forming region is connected between the upper end and the lower end of the frame region in the thickness direction of the frame region, In the thickness direction of the metal sheet, the neutral plane of the metal sheet is located inside the opening forming region.

4. The mask assembly according to claim 1, wherein: The metal sheet further includes at least one dummy area, which is arranged inside the grid, has the same thickness as the frame area, and does not form the opening portion. The opening forming regions and the dummy regions are arranged in a matrix form, and the opening forming regions and the dummy regions are arranged alternately.

5. The mask assembly according to claim 4, wherein: The opening forming regions and the dummy regions are arranged alternately with each other in each row and each column.

6. The mask assembly according to claim 4, wherein: In one of the rows adjacent to each other, the opening forming region is arranged, and in the other row, the dummy region is arranged.

7. The mask assembly according to claim 1, wherein: The thickness of the frame area is 8um to 100um, and the thickness of the opening forming area is 0.5um to 8um.

8. The mask assembly according to claim 7, wherein: The thickness of the opening forming region is 2 um to 6 um.

9. A method for manufacturing a mask assembly, the mask assembly being used in a thin film process, comprising: preparing a metal sheet, the metal sheet being divided into a frame region in a grid shape and an opening forming region arranged inside the grid; removing a portion of the thickness of the opening forming area; forming a plurality of openings in the opening forming region; stretching the metal sheet having the opening formed therein; as well as Arranging mask frames corresponding to the frame areas at both ends of the metal sheet, The thickness of the frame region is greater than the thickness of the opening forming region. In the thickness direction of the metal sheet, the neutral plane of the metal sheet is located inside the opening forming region or between a position of 50% of the thickness of the metal sheet and a surface of the opening forming region.

10. The method for manufacturing a mask assembly according to claim 9, wherein: The opening forming region is connected to one of an upper end and a lower end of the frame region in a thickness direction of the frame region, In the thickness direction of the metal sheet, the neutral plane of the metal sheet is located between a position at a distance of 30% of the thickness of the metal sheet from the surface of the opening forming region and the surface of the opening forming region.

11. The method for manufacturing a mask assembly according to claim 10, wherein: The step of removing part of the thickness of the opening forming area comprises: Arranging a photosensitive film on one side of the metal sheet; exposing and developing the photosensitive film to expose the opening forming area; and The removal is performed by etching a portion of the thickness of the opening formation region using the photosensitive film that exposes the opening formation region as a mask.

12. The method for manufacturing a mask assembly according to claim 9, wherein: The opening forming region is connected between the upper end and the lower end of the frame region in the thickness direction of the frame region, In the thickness direction of the metal sheet, the neutral plane of the metal sheet is located inside the opening forming region.

13. The method for manufacturing a mask assembly according to claim 12, wherein: The step of removing part of the thickness of the opening forming area comprises: A first process of removing a portion of the thickness of the opening forming area from one side of the metal sheet; and A second process of removing a portion of the thickness of the opening forming area from the other side of the metal sheet, Wherein, the first process and the second process include: forming a photosensitive film on the metal sheet, wherein the photosensitive film exposes the opening forming area; and The removal is performed by etching a portion of the thickness of the opening formation region using the photosensitive film that exposes the opening formation region as a mask.

14. The method for manufacturing a mask assembly according to claim 9, wherein: The metal sheet further includes at least one dummy area, which is arranged inside the grid, has the same thickness as the frame area, and does not form the opening portion. The opening forming regions and the dummy regions are arranged in a matrix form, The opening forming regions and the dummy regions are arranged alternately.

15. The method for manufacturing a mask assembly according to claim 14, wherein: The opening forming regions and the dummy regions are arranged alternately with each other in each row and each column.

16. The method for manufacturing a mask assembly according to claim 14, wherein: In one of the rows adjacent to each other, the opening forming region is arranged, and in the other row, the dummy region is arranged.

17. The method for manufacturing a mask assembly according to claim 9, wherein: The thickness of the opening forming region is 2 um to 6 um.

18. The method for manufacturing a substrate according to claim 17, comprising: The thickness of the opening forming region is 2 um to 6 um.

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