Mask metal film and manufacturing method thereof

Abstract

The invention relates to a mask metal film and a manufacturing method thereof. The method for manufacturing a mask metal film according to the present invention is used for manufacturing a mask for OLED pixel formation, and comprises the steps of: (a) preparing a mask metal film manufactured based on a rolling process; (b) carrying out surface defect removal and thickness reduction on the first surface of the mask metal film; in the step (b), a defect having a length of 1 [mu] m to 100 [mu] m and a depth of more than 0 and less than 5 [mu] m in at least one direction on the first surface of the mask metal film is defined as a surface defect, and the surface defect is removed by thinning the thickness of the mask metal film by 3 [mu] m to 13 [mu] m.

Description

Technical Field

[0001] The present invention relates to a mask metal film and a method for manufacturing the same, and more particularly to a mask metal film capable of realizing high-resolution OLED pixels by forming a fine mask pattern and a method for manufacturing the same. Background Art

[0002] As a technology for forming pixels in an OLED (Organic Light Emitting Diode) manufacturing process, a fine metal mask (FMM) method is mainly used, in which a metal mask (Shadow Mask) in the form of a thin film is closely attached to a substrate and an organic substance is deposited at a desired position.

[0003] In the existing OLED manufacturing process, after the mask is manufactured into strips, plates, etc., the mask is welded and fixed to the OLED pixel deposition frame and used. A mask can have multiple units corresponding to one display. In addition, in order to manufacture large-area OLEDs, multiple masks can be fixed to the OLED pixel deposition frame, and in the process of fixing them to the frame, each mask is stretched to make it flat. Adjusting the stretching force to make the entire part of the mask flat is a very difficult task. In particular, in order to make all the units flat and align the mask pattern with a size of only a few μm to tens of μm, it is necessary to fine-tune the stretching force applied to each side of the mask and confirm the alignment status in real time, which is a difficult task.

[0004] Nevertheless, in the process of fixing multiple masks to a frame, there is still the problem of poor alignment between masks and between mask units. In addition, in the process of welding the mask to the frame, the thickness of the mask film is too thin and the area is large, so there is a problem that the mask sags or twists due to the load; wrinkles and burrs generated in the welding part during the welding process lead to the problem of misalignment of the mask unit, etc.

[0005] In ultra-high-definition OLEDs, the existing QHD image quality is 500 to 600 PPI (pixel per inch), and the pixel size is about 30 to 50 μm, while 4K UHD and 8K UHD high-definition images have higher resolutions such as -860 PPI and -1600 PPI. In this way, considering the pixel size of ultra-high-definition OLEDs, the alignment error between units needs to be reduced to about a few μm. Exceeding this error will result in defective products, so the yield may be extremely low. Therefore, it is necessary to develop technologies that can prevent deformation such as sagging or twisting of the mask and make the alignment precise, as well as technologies that fix the mask to the frame.

[0006] In addition to preventing mask deformation and accurate alignment, a technology that can clearly form a mask pattern on a mask metal film is also required. Defects on the surface or inside of the mask metal film may have an adverse effect on the process of forming the mask pattern. Therefore, in addition to the process of finely forming the mask pattern, it is particularly important to use a mask metal film without defects such as impurities and inclusions. Summary of the invention

[0007] Technical issues

[0008] Therefore, the present invention is proposed to solve the above-mentioned problems in the prior art, and an object of the present invention is to provide a mask metal film capable of forming a fine mask pattern on a mask and a method for manufacturing the same.

[0009] Another object of the present invention is to provide a mask metal film and a method for manufacturing the same, wherein the surface and internal quality characteristics of the mask metal film do not adversely affect the formation of a mask pattern.

[0010] Another object of the present invention is to provide a mask and frame connection body and a method for manufacturing the same, which can stably support and move a mask without deformation, prevent the mask from deforming such as sagging or twisting, and accurately align the mask.

[0011] Furthermore, an object of the present invention is to provide a mask and frame connection body and a method for manufacturing the same, which can significantly reduce manufacturing cost and manufacturing time and significantly improve productivity.

[0012] However, the above technical problems are for illustrative purposes, and the scope of the present invention is not limited thereto.

[0013] Technical Solution

[0014] The above-mentioned object of the present invention is achieved through a method for manufacturing a mask metal film, which is used to manufacture a mask for forming OLED pixels. The method includes the following steps: (a) preparing a mask metal film made based on a rolling process; (b) removing surface defects and reducing the thickness on the first surface of the mask metal film; defects on the first surface of the mask metal film with a length of 1μm to 100μm along at least one direction and a depth of less than 5μm (greater than 0) are defined as surface defects. In the step (b), the surface defects are removed by reducing the thickness of the mask metal film by 3μm to 13μm.

[0015] The method further includes the following steps: (c) removing surface defects and reducing thickness on the second surface opposite to the first surface of the mask metal film; defects on the second surface of the mask metal film with a length of 1 μm to 100 μm along at least one direction and a depth of less than 5 μm (greater than 0) are defined as surface defects. In the step (c), the surface defects are removed by reducing the thickness of the mask metal film by 3 μm to 13 μm.

[0016] After the step (b), the surface defects on the first surface are completely removed or only the surface defects with a length of less than 1 μm and a depth of less than 1 μm along at least one direction remain.

[0017] The step (b) is performed by wet etching.

[0018] The step (b) is performed by further utilizing at least one of lapping, polishing, and buffing based on the etching method.

[0019] The thickness of the mask metal film in the step (a) is 35 μm to 45 μm.

[0020] The thickness of the mask metal film in the step (a) is 35 μm to 45 μm, and after the step (c), the thickness of the mask metal film is 15 μm to 30 μm.

[0021] Before the step (b), any 1 cm 2 The number of the surface defects present in the region is greater than 0 and less than 50.

[0022] The surface defects include dent type, line type, and scratch type. In the step (b), if the thickness of the mask metal film is reduced by 3 μm, the surface defects of the dent type, line type, and scratch type will be removed.

[0023] The mask metal film is at least any one of invar, super invar, nickel (Ni), nickel-cobalt (Ni-Co), cobalt (Co), titanium (Ti), chromium (Cr), tungsten (W), and molybdenum (Mo), and the surface defects include inclusions, and the inclusions contain at least any one of carbon, aluminum oxide, and manganese sulfide.

[0024] Taking the thickness direction of the mask metal film as a reference, a defect having a length of 1 μm to 5 μm along at least one direction and a depth of less than 2 μm (greater than 0) in a deeper region than the portion thinned in the step (b) is defined as an internal defect. After the step (b), any 1 cm on the first surface of the mask metal film 2 The number of said internal defects present in the region is less than 15.

[0025] The mask metal film is at least one material selected from the group consisting of invar, super invar, nickel (Ni), nickel-cobalt (Ni-Co), cobalt (Co), titanium (Ti), chromium (Cr), tungsten (W), and molybdenum (Mo), and the internal defects contain at least one component selected from the group consisting of oxide and manganese sulfide of the material of the mask metal film.

[0026] In addition, the above-mentioned purpose of the present invention is achieved by a mask metal film, which is used to manufacture a mask for forming OLED pixels. The mask metal film is made based on a rolling process, and a thickness thinning of 3μm to 13μm is performed on the first surface of the mask metal film to remove surface defects. The surface defects are defined as defects with a length of 1μm to 100μm along at least one direction and a depth of less than 5μm (greater than 0) on the first surface of the mask metal film, so that the surface defects on the first surface are completely removed or surface defects with a length of less than 1μm and a depth of less than 1μm along at least one direction remain.

[0027] The thickness of the mask metal film is 15 μm to 30 μm. When a defect having a length of 1 μm to 5 μm in at least one direction and a depth of less than 2 μm (more than 0) in a deeper region compared to the portion with a reduced thickness in the thickness direction of the mask metal film is defined as an internal defect, any 1 cm on the first surface of the mask metal film 2 The number of said internal defects present in the region is less than 15.

[0028] In addition, the above-mentioned object of the present invention is achieved by a mask metal film, which is used to manufacture a mask for forming OLED pixels, the mask metal film is made based on a calendering process, the thickness of the mask metal film is 15 μm to 30 μm, and when a defect with a length of 1 μm to 5 μm along at least one direction and a depth of less than 2 μm (greater than 0) is defined as an internal defect, any 1 cm on at least one side of the mask metal film 2 The number of said internal defects present in the region is less than 15.

[0029] Beneficial Effects

[0030] According to the present invention having the above-described structure, there is an effect that a fine mask pattern can be formed on the mask.

[0031] Furthermore, according to the present invention, there is provided a mask metal film having surface and internal quality characteristics that does not adversely affect the formation of a mask pattern.

[0032] Furthermore, according to the present invention, there are effects that the mask can be supported and moved stably without deformation, and that deformation such as sagging or twisting of the mask can be prevented and alignment can be performed accurately.

[0033] Furthermore, according to the present invention, there is an effect that the manufacturing cost and the manufacturing time can be significantly reduced and the productivity can be significantly improved.

[0034] Of course, the scope of the present invention is not limited by the above-mentioned effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic diagram of the process of attaching an existing mask to a frame.

[0036] Figure 2 1 is a front view and a side cross-sectional view of a connection body of a mask and a frame according to an embodiment of the present invention.

[0037] Figure 3 1 is a schematic top view and a side cross-sectional view of a mask according to an embodiment of the present invention.

[0038] Figures 4 to 8 1 is a schematic diagram of a manufacturing process of a stack of a mask and a moving plate according to an embodiment of the present invention. In each step, the upper figure is a schematic side cross-sectional view, and the lower figure is a schematic top view.

[0039] Fig. 9 and Fig.10 FIG. 4 is a schematic diagram of a manufacturing process of a stack of a mask and a moving plate according to another embodiment of the present invention.

[0040] Fig.11 It is a schematic side cross-sectional view of a mask pattern forming process according to a comparative example.

[0041] Fig.12 is based on Fig.11 A partially enlarged side cross-sectional view of a mask pattern of a mask according to a comparative example.

[0042] Figure 13 to Figure 14 is a schematic side cross-sectional view of a mask pattern forming process according to an embodiment of the present invention.

[0043] Fig.15 is a partially enlarged side cross-sectional view of a mask pattern of a mask according to an embodiment of the present invention.

[0044] Fig.16FIG. 1 is a schematic diagram of a process of loading a stack of a mask and a moving plate into a frame according to an embodiment of the present invention.

[0045] Fig.17 2 is a schematic diagram of a state in which a moving plate is loaded onto a frame and a mask is matched to a unit area of ​​the frame according to an embodiment of the present invention.

[0046] Fig.18 FIG. 1 is a partially enlarged side cross-sectional view showing a state in which a welding bead is formed in a notch portion according to an embodiment of the present invention.

[0047] Fig.19 2 is a schematic diagram of a process of separating the mask from the moving plate after the mask is connected to the frame according to an embodiment of the present invention.

[0048] Fig. 20 FIG. 4 is a schematic diagram of a state where a mask is connected to a frame according to an embodiment of the present invention.

[0049] Fig.21 FIG. 1 is a schematic diagram of an OLED pixel deposition apparatus using a connector of a mask and a frame according to an embodiment of the present invention.

[0050] Fig. 22 is a schematic diagram of a mask metal film according to an embodiment of the present invention.

[0051] Fig.23 FIG. 4 is a schematic diagram of surface defects of a mask metal film according to an embodiment of the present invention.

[0052] Fig.24 FIG. 4 is a schematic diagram of surface defect types of a mask metal film according to an embodiment of the present invention.

[0053] Fig.25 FIG. 4 is a schematic diagram of a process for manufacturing a mask metal film according to an embodiment of the present invention.

[0054] Fig.26 1 and 2 are optical microscope photos and focused ion beam (FIB) photos of surface defect types of a mask metal film according to an embodiment of the present invention.

[0055] Fig. 27 1 and 2 are optical microscope photographs and focused ion beam photographs of internal defect types of a mask metal film according to an embodiment of the present invention.

[0056] Fig.28 It is an analysis curve diagram of surface defects and internal defects in any three regions of the mask metal film according to an embodiment of the present invention.

[0057] Fig.29 FIG. 4 is a schematic diagram of surface defect removal based on the thickness reduction degree of the mask metal film according to an embodiment of the present invention.

[0058] [Description of Reference Numerals]

[0059] 10: Connector of mask and frame 20: Lamination of mask and moving plate

[0060] 50: moving plate 55: dry film resist layer

[0061] 100: Mask 110: Mask film, mask metal film

[0062] 115": Central part of the mask metal film 200: Frame

[0063] 210: Edge frame portion 220: Mask unit sheet portion

[0064] 221: Edge sheet portion 223: First grid sheet portion

[0065] 225: Second grid sheet section C: unit section, mask unit section

[0066] CR: Mask cell region DM: Dummy portion, mask dummy portion

[0067] L: Laser M1, M2: First insulating part, second insulating part

[0068] P: mask pattern P1, P2: first mask pattern, second mask pattern

[0069] PS1, PS2: Thickness reduction process RC: Notch

[0070] WB: Weld Bead WP: Welding Part DETAILED DESCRIPTION

[0071] The present invention will be described in detail below with reference to the accompanying drawings, which exemplarily illustrate specific embodiments that can implement the present invention. These embodiments are described in sufficient detail so that those skilled in the art can implement the present invention. It should be understood that the various embodiments of the present invention, although different from each other, do not necessarily exclude each other. For example, the specific shapes, structures and characteristics recorded herein are related to an embodiment and can be implemented as other embodiments without departing from the spirit and scope of the present invention. In addition, it should be understood that the position or configuration of individual constituent elements in each disclosed embodiment can be changed without departing from the spirit and scope of the present invention. Therefore, the detailed description described below should not be regarded as having a limiting meaning. As long as it is properly explained, the scope of the present invention is limited only by the attached claims and all scopes equivalent thereto. Similar reference numerals in the figure represent the same or similar functions from many aspects, and for convenience, length, area, thickness and shape thereof can be exaggerated.

[0072] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

[0073] Figure 1 It is a schematic diagram of the existing process of attaching the mask 1 to the frame 2.

[0074] The existing mask 1 is a stick-type or a plate-type. Figure 1 The rod-type mask 10 can be used by welding both sides of the rod to the OLED pixel deposition frame. The body (Body) of the mask 1 [or the mask film 1a] has a plurality of display unit parts C. One unit part C can correspond to a display of a smartphone, etc. A pixel pattern corresponding to each pixel of the display is formed on the unit part C.

[0075] Reference Figure 1 (a), the rod-shaped mask 1 is loaded onto the frame 2 of a quadrilateral frame shape in an unfolded state by applying a tensile force F1-F2 along the long axis direction of the rod-shaped mask 1. The cells C1-C6 of the rod-shaped mask 1 will be located in the blank area inside the frame 2.

[0076] Reference Figure 1 (b), after fine-tuning the tensile force F1-F2 applied to each side of the rod-shaped mask 1 and aligning it, the rod-shaped mask 1 and the frame 2 are connected to each other by welding W to a part of the side surface of the rod-shaped mask 10. Figure 1 (c) illustrates a side section of the rod-shaped mask 1 and the frame connected to each other.

[0077] Despite the fine adjustment of the tensile force F1-F2 applied to each side of the rod-shaped mask 1, the problem of poor alignment between the mask units C1-C6 still occurs. The distances between the patterns of the units C1-C6 are different from each other or the pixel patterns are not aligned. This is an example. Since the rod-shaped mask 1 includes multiple units C1-C6 and has a large area and a very thin thickness of tens of μm, it is easy to sag or twist due to the load. In addition, in order to make all the units C1-C6 in a flat state, it is a very difficult task to adjust the tensile force F1-F2 while observing the alignment state between the units C1-C6 through a microscope. In order to prevent the pixel pattern (or mask pattern) with a size of several μm to tens of μm from having an adverse effect on the pixel process of the ultra-high-quality OLED, the alignment error is preferably not more than 3μm. This alignment error between adjacent units is called pixel position accuracy (PPA).

[0078] In addition, multiple rod-shaped masks 1 are respectively connected to a frame 2, and confirming the alignment status between multiple rod-shaped masks 1 and multiple units C1-C6 of the rod-shaped masks 1 is also a very difficult task. The alignment operation will increase the process time and become a major reason for reducing production efficiency.

[0079] Furthermore, after the rod-shaped mask 1 is connected and fixed to the frame 2, the tensile force F1-F2 applied to the rod-shaped mask 1 can react as tension to the frame 2. This tension can slightly deform the frame 2 and distort the alignment state between the plurality of cells C1-C6.

[0080] Therefore, the present invention provides a mask and frame connector 10 that enables the mask 100 and the frame 200 to form an integrated structure. The mask 100 formed integrally with the frame 200 can prevent deformation such as sagging and twisting, and can be accurately aligned on the frame 200.

[0081] Figure 2 is a front view of a mask and frame connector 10 according to an embodiment of the present invention. Figure 2 (a)] and side cross-sectional view [ Figure 2 (b)].

[0082] In this specification, the configuration of the connector 10 of the mask and frame will be briefly described below, but the structure and manufacturing process of the connector 10 of the mask and frame can be understood to include the entire content of Korean Patent Application No. 2018-0016186.

[0083] Reference Figure 2 The connector 10 of the mask and the frame may include a plurality of masks 100 and a frame 200. In other words, the plurality of masks 100 are connected to the frame 200 one by one. For the sake of convenience, the following description takes a quadrilateral mask 100 as an example, but the shape of the mask 100 is not limited as long as it can be connected to the frame 200.

[0084] A plurality of mask patterns P are formed on each mask 100 , and one unit portion C may be formed on one mask 100 . One mask unit portion C may correspond to a display of a smartphone, etc. Alternatively, a small number of unit portions C may be formed on the mask 100 .

[0085] The material of the mask 100 may also be invar, super invar, nickel (Ni), nickel-cobalt (Ni-Co), cobalt (Co), titanium (Ti), chromium (Cr), tungsten W, manganese (Mo), etc. The mask 100 may use a metal sheet generated by a rolling process or electroforming.

[0086] The frame 200 is formed to connect a plurality of masks 100. For thermal deformation considerations, the frame 200 is preferably made of the same material as the mask. The frame 200 may include an edge frame portion 210 that is substantially quadrilateral or quadrilateral frame-shaped. The interior of the edge frame portion 210 may be hollow.

[0087] In addition, the frame 200 has a plurality of mask unit regions CR, and may include a mask unit sheet portion 220 connected to the edge frame portion 210. The mask unit sheet portion 220 may be composed of an edge sheet portion 221 and a first grid sheet portion 223 and a second grid sheet portion 225. The edge sheet portion 221 and the first grid sheet portion 223 and the second grid sheet portion 225 refer to portions divided on the same sheet, and they are integrated with each other.

[0088] The thickness of the edge frame portion 210 is greater than that of the mask unit sheet portion 220 and is formed by a thickness of several mm to several cm. The thickness of the mask unit sheet portion 220 may be less than the thickness of the edge frame portion 210 but greater than the thickness of the mask 100, and is about 0.1 mm to 1 mm. The width of the first grid sheet portion 223 and the second grid sheet portion 225 is about 1 to 5 mm.

[0089] In the planar sheet, excluding the region occupied by the edge sheet portion 221 and the first and second grid sheet portions 223 and 225 , a plurality of mask unit regions CR ( CR11 - CR56 ) may be provided.

[0090] The frame 200 has a plurality of mask unit regions CR [refer to Fig.17 ], each mask 100 can be attached in a manner that each mask unit portion C corresponds to the mask unit region CR. The mask unit portion C corresponds to the mask unit region CR of the frame 200, and part or all of the dummy portion can be attached to the frame 200 [mask unit sheet portion 220]. Thus, the mask 100 and the frame 200 can form an integrated structure.

[0091] Figure 3 1 is a schematic top view and a side cross-sectional view of a mask 100 according to an embodiment of the present invention.

[0092] Reference Figure 3, the mask 100 may include a mask unit portion C formed with a plurality of mask patterns P and a dummy portion DM located around the mask unit portion C. The mask 100 may be made of a metal sheet produced by a rolling process, electroforming, etc., and one unit portion C or a plurality of unit portions C may be formed on the mask 100. The dummy portion DM corresponds to a portion of the mask film 110 [mask metal film 110] other than the unit portion C, and may include only the mask film 110, or may include a mask film 110 formed with a predetermined dummy portion pattern similar to the mask pattern P. The dummy portion DM corresponds to an edge of the mask 100, and a portion or all of the dummy portion DM may be attached to the frame 200 [mask unit sheet portion 220].

[0093] The width of the mask pattern P may be less than 40 μm, and the thickness of the mask 100 may be about 5 to 30 μm, preferably 15 to 30 μm. Since the frame 200 has a plurality of mask unit regions CR (CR11 to CR56), it may also have a plurality of masks 100 having mask unit portions C (C11 to C56) corresponding to the respective mask unit regions CR (CR11 to CR56).

[0094] The mask 100 may provide a first surface 101 and a second surface 102 which is the opposite surface of the first surface 101. The opening width of the mask pattern P [or the second mask pattern P2] opened toward the first surface 101 may be smaller than the opening width of the mask pattern P [or the first mask pattern P1] opened toward the second surface 102. When viewed from another angle, the shape of the mask pattern P may be a cone / inverted cone shape as a whole.

[0095] Figures 4 to 8 1 is a schematic diagram of a manufacturing process of a stacked body 20 of a mask 100 and a moving plate 50 according to an embodiment of the present invention. In each step, the upper figure is a schematic side cross-sectional view, and the lower figure is a schematic top view.

[0096] First, refer to Figure 4 (a) A mask metal film 110 may be provided, and the second surface 102 of the mask metal film 110 is bonded to the transfer substrate 40. The transfer substrate 40 is temporarily used in the manufacturing process of the mask 100, but is not used to support the mask 100 and load the mask 100 onto the frame 200, that is, it is not used as the moving plate 50. The transfer substrate 40 may be made of glass, quartz, etc., and may be in a flat plate shape with an area larger than the mask metal film 110, so as to perform the process of forming the notch portion RC of the mask metal film 110.

[0097] An adhesive portion 45 may be sandwiched between the transfer substrate 40 and the mask metal film 110. The adhesive portion 45 may be made of the same material as the dry film resist 55 described later. Alternatively, since the transfer substrate 40 will be separated from the mask metal film 110 in a subsequent process, the adhesive portion 45 may also be made of a material that can be removed and cleaned after temporarily providing adhesive force. Figure 4 The recessed portion RC formed in step (b) plays a bonding role so that the mask metal film 110 does not move on the transfer substrate 40 .

[0098] In addition, before forming the recessed portion RC / mask pattern P, other pattern forming processes such as etching may be used to form the first alignment hole AH1 and the second alignment hole AH2 on the mask metal film 110 .

[0099] The first alignment hole AH1 can be used to align the positions of the second mask pattern P2 and the first mask pattern P1 on the mask metal film 110, and can also be used to align the insulating parts M1 and M2, which are used to form the second mask pattern P2 and the first mask pattern P1. The second alignment hole AH2 can be used to align the mask metal film 110 and the moving plate 50 [refer to Figure 5 (d)] position.

[0100] The mask metal film 110 may include a region for forming the mask pattern P (P1, P2), namely, the mask unit portion C and dummy portions DM1, DM2 around the mask unit portion C. The first alignment hole AH1 and the second alignment hole AH2 may be formed in the dummy portions DM1, DM2 of the mask metal film 110, and the dummy portions DM1, DM2 are preferably formed in the second dummy portion DM2. The first dummy portion DM1, as a region for forming the notch portion RC and the welding portion WP, is included within the range of the mask 100, and the second dummy portion DM2 may be a portion that is cut or removed during or after the manufacturing process of the mask 100. That is, the second dummy portion DM2 may be a portion that corresponds only to the movable plate 50 [refer to Figure 5 (d)] area.

[0101] Then, refer to Figure 4 (b), a recess portion RC may be formed on the mask metal film 110 bonded to the transfer substrate 40. The recess portion RC may be formed on the first surface 101 of the mask metal film 110. The recess portion RC may be formed at a depth that does not penetrate the mask metal film 110 from the first surface 101 of the mask metal film 110.

[0102] First, a dry film resist layer 55 (DFR layer) can be formed on the first surface 101 of the mask metal film 110. The dry film resist layer 55 can be provided as a thin film photoresist. As an example, the lamination process can be performed immediately after soft baking at about 60°C for 60 seconds. The photoresist layer of DFR can be laminated to the first surface 101 of the mask metal film 110 while stripping off the protective film of DFR. Lamination can be performed in a low-temperature process of about 60°C or less with a preset roller pressure. Lamination is preferably performed in a vacuum state. Lamination in a vacuum state can prevent the occurrence of bubbles on the interface between the dry film resist layer 55 and the mask metal film 110 / movable plate 50.

[0103] The present invention utilizes the dry film resist layer 55 to perform bonding, lithography, etc. in a low temperature region below about 60°C, thereby having the effect of preventing the mask metal film 110 [or, mask 100] from being deformed due to heat during the process steps. In addition, due to the use of the dry film resist layer 55, the baking time and exposure processing time are significantly reduced compared to the use of liquid photoresist. Compared to liquid photoresist, it takes about 1 hour to bake and expose for outgassing, but only about 2 minutes if a dry film resist is used, thereby significantly reducing the process time.

[0104] After the dry film resist layer 55 is exposed and developed, the recess pattern 56 can be formed. Next, by wet etching, dry etching, etc., the space between the recess patterns 56, the recess portion RC can be formed.

[0105] The notch portion RC may be formed in a welding region WR for arranging the welding portion WP later. The welding region WR may correspond to the first dummy portion DM1 included in the mask 100 in the dummy portion other than the mask unit portion C. The welding region WR may correspond to an edge of the mask unit region CR of the frame 200.

[0106] Step difference WS [reference Fig.18 ] is a space for forming the notch RC, which is used to prevent the welding bead WB [or welding burr] from protruding upward and contacting the target substrate 1900 [refer to Fig.18 and Fig.21 Due to the step WS of the notch RC, even if the weld bead WB protrudes upward, it can be prevented from protruding above the upper surface of the mask 100.

[0107] Then, refer to Figure 5(c) A movable plate 50 may be provided. The movable plate 50 is a medium that can be transferred in a state where the mask 100 is attached thereto and supports the mask 100. The movable plate 50 is used in the manufacturing process of the mask 100, and can be used to attach the mask 100, support it, and transfer it to the frame 200, and is used to load the mask 100 onto the frame 200.

[0108] The movable plate 50 may be made of a material that is transparent to the laser L. The movable plate 50 may be made of glass, silica, quartz, alumina (Al2O3), borosilicate glass, zirconia, and the like.

[0109] The movable plate 50 is preferably made of a glass material that is easy to process and inexpensive, and more preferably a borosilicate glass material. In particular, borosilicate glass having excellent heat resistance, chemical resistance, mechanical strength, and transparency can be used. 33 materials. In addition, The thermal expansion coefficient of 33 is about 3.3, which has a small difference in thermal expansion coefficient with the mask metal film 110 made of Invar material, which is beneficial to control the mask metal film 110.

[0110] Next, the transfer substrate 40 may be moved onto the moving plate 50. The transfer substrate 40 may be turned over so that the first surface 101 of the mask metal film 110 faces the moving plate 50. The first surface 101 of the mask metal film 110 having the notch RC formed thereon faces the upper surface of the moving plate 50.

[0111] Then, refer to Figure 5 (d), the first surface 101 of the mask metal film 110 can be bonded to the moving plate 50. Figure 5 The dry film resist layer 550 used to form the notch RC in step (c) provides adhesive force while maintaining the original state. Therefore, it is possible to flip the transfer substrate 40 and directly bond the first surface 101 of the mask metal film 110 to the movable plate 50 without using other bonding components. The movable plate 50 and the mask metal film 110 can be bonded to each other by sandwiching the dry film resist layer 55.

[0112] Optionally, in order to strengthen the adhesion between the moving plate 50 and the mask metal film 110 , a dry film resist layer 55 may be further formed.

[0113] According to Korean Patent Application No. 2020-0043485 Fig.11The prior art uses liquid wax to bond the mask metal film to the substrate supporting the mask metal film. The liquid wax layer is baked at a temperature of about 100 to 160°C in order to vaporize the solvent during use, and the lamination process is also carried out at a temperature of about 110°C. Therefore, in the high temperature region above 100°C, the mask metal film may have the problem of thermal deformation. In addition, in order to form the etching pattern, liquid wax also uses liquid photoresist. That is, in the prior art, a liquid wax layer and a liquid photoresist layer are used between the mask metal film and the substrate supporting the mask metal film.

[0114] On the contrary, the present invention can have the following characteristics by using the dry film resist layer 55: Figure 4 The bonding process can be performed in a low temperature region below about 60°C as described in (a). In addition, there is no need to use a liquid wax layer and a liquid photoresist layer separately, and only the dry film resist layer 55 can achieve two purposes, namely bonding and forming an etching pattern. Figure 4 As shown in (a), the recess pattern 56 can be formed, and the purpose of combining the mask metal film 110 and the moving plate 50 can be achieved. In addition, as described later, the dry film resist layer 55 can even provide etching resistance and adhesion to the mask metal film 110 during the formation of the second mask pattern P2.

[0115] Next, the transfer substrate 40 may be separated (debonded) from the mask metal film 110. The separation of the mask metal film 110 and the transfer substrate 40 may be performed by performing at least one of heating ET, chemical treatment CM, application of ultrasonic wave US, and application of ultraviolet light UV on the adhesive portion 45. If at least one of heating ET, chemical treatment CM, application of ultrasonic wave US, and application of ultraviolet light UV is performed on the adhesive portion 45, the adhesive force between the mask metal film 110 and the transfer substrate 40 is weakened, so that the mask metal film 110 and the transfer substrate 40 can be separated. After the transfer substrate 40 is separated, the adhesive portion 45 remaining in the mask metal film 110 may be removed by washing or the like.

[0116] Then, refer to Figure 6(e), a planarization process PS can be performed on the second surface 102 of the mask metal film 110. The planarization PS refers to the process of reducing the thickness by mirroring the second surface 102 (upper surface) of the mask metal film 110 while removing a portion of the upper portion of the mask metal film 110. The planarization PS can be performed using a CMP (Chemical Mechanical Polishing) method, and any known CMP method can be used. In addition, the thickness of the mask metal film 110 can also be reduced by a chemical wet etching method or a dry etching method. In addition, any planarization process that can reduce the thickness of the mask metal film 110 can be used.

[0117] The mask metal film 110 manufactured by the rolling process can be thinned by the planarization process PS. In addition, in order to control the surface characteristics and thickness, the mask metal film 110 manufactured by the electroforming process can also be subjected to the planarization process PS. By thinning the thickness of the mask metal film 110, the thickness of the mask metal film 110 can be about 5 μm to 30 μm.

[0118] The thickness reduction may be performed on the area for forming the first mask pattern P1 and the second mask pattern P2 in the mask unit part C. On the contrary, for the area where the notch portion RC is formed, it is necessary to ensure the thickness of the mask metal film 110 so that sufficient weld beads WB can be formed during the subsequent welding. Therefore, for the dummy part DM, especially the area where the notch portion RC is formed, i.e., the first dummy part DM1, it is preferred not to perform the thickness reduction. The thickness of the portion that is not subjected to the thickness reduction is greater than the thickness of the remaining portion and can be provided as the area for laser welding, i.e., the welding part WP.

[0119] The mask metal film 110 is bonded to the moving plate 50 with the dry film resist layer 55 interposed therebetween, so that the mask metal film 110 can also maintain a constant position during the planarization process PS.

[0120] Then, refer to Figure 6 (f), a first mask pattern P1 may be formed on the second surface 102 of the mask metal film 110 .

[0121] The first mask pattern P1 can be formed by forming a patterned first insulating portion M1 on the second surface 102 of the mask metal film 110 and etching in the space between the patterns of the first insulating portion M1. The first mask pattern P1 can be formed in the mask unit portion C region of the mask metal film 110. The first insulating portion M1 can be formed of a photoresist material using a printing method, etc., and etching can use, but is not limited to, dry etching and wet etching.

[0122] As an example, when wet etching is used, undercut occurs due to isotropic etching, and therefore, the width PA' of the first mask pattern P1 may be larger than the inter-pattern width PA of the first insulating portion M1. In view of this, it is preferred to set the inter-pattern width of the first insulating portion M1. In addition, due to isotropic etching, the lower surface width of the first mask pattern P1 is not easy to control, and therefore, preferably, the first mask pattern P1 is formed so that its thickness is less than the thickness of the mask metal film 110. That is, preferably, the first mask pattern P1 is formed without penetrating the mask metal film 110. According to one embodiment, the thickness of the mask metal film 110 is about 20 μm, and the first mask pattern P1 can be formed with a thickness of about 15 to 18 μm. The width PA' of the first mask pattern P1 may be about 30 to 40 μm, but is not limited thereto.

[0123] In addition, the first mask pattern P1 may penetrate the mask metal film 110 . However, in this case, the penetrated portion can be readjusted to the form of the second mask pattern P2 in the process of forming the second mask pattern P2 described later.

[0124] Then, refer to Figure 7 (g) A second mask pattern P2 may be formed on the second surface 102 of the mask metal film 110. The second mask pattern P2 may be formed to penetrate from the first mask pattern P1 to the first surface 101 of the mask metal film 110.

[0125] The second mask pattern P2 can be formed by forming a patterned second insulating portion M2 on the second surface 102 of the mask metal film 110 and the first mask pattern P1, and etching in the pattern space of the second insulating portion M2. The second mask pattern P2 can be formed in the mask unit portion C region of the mask metal film 110. The second insulating portion M2 can be formed of a photoresist material using a printing method, etc., and etching can use, but is not limited to, dry etching and wet etching methods.

[0126] As an example, when wet etching is used, undercut occurs due to isotropic etching, so the width PB' of the second mask pattern P2 may be larger than the width PB between patterns of the second insulating portion M2. Therefore, preferably, the second mask pattern P2 is formed with a very thin thickness compared to the thickness of the mask metal film 110. Only by forming the second mask pattern P2 with a very thin thickness can the error between the width PB between patterns of the isotropically etched second insulating portion M2 and the width PB' of the second mask pattern P2 be minimized. According to one embodiment, the thickness of the mask metal film 110 is about 20 μm, then the first mask pattern P1 can be formed with a thickness of about 15 to 18 μm, and the second mask pattern P2 is formed with a thickness of about less than 5 μm, preferably, with a thickness of about less than 2 μm. The width PB' of the second mask pattern P2 may be about 10 to 25 μm.

[0127] By forming the second mask pattern P2 , the mask metal film 110 may be penetrated, and the mask pattern P may be formed by the sum of the first mask pattern P1 and the second mask pattern P2 . By forming a plurality of mask patterns P, the mask metal film 110 may be provided as the mask 100 .

[0128] Then, refer to Figure 8 (h), after removing the second insulating portion M2, subsequent processes such as cleaning may be performed. Then, the mask 100 may sandwich a dry film resist layer 55 on the movable plate 50, and the manufacture of the laminated body 20 (20-1) of the mask and the movable plate for bonding support is completed.

[0129] The second mask pattern P2 of the mask 100 in the stacked body 20 of the mask and the moving plate has a smaller thickness and width than the first mask pattern P1. Therefore, the shape of the mask pattern P as a whole may be a cone / inverted cone shape like the first mask pattern P1. However, the organic source 1600 [refer to Fig.21 ] The pixel 1700 of the OLED is substantially formed based on the width PB' of the second mask pattern P2, so that the size of the pixel can be determined according to the width PB' of the second mask pattern P2.

[0130] In the present invention, the formation of the first mask pattern P1 and the second mask pattern P2 can be performed on the same second surface 102 of the mask metal film 110. The mask metal film 110 can continuously form the first mask pattern P1 and the second mask pattern P2 on the same second surface 102 without being transferred to other substrates in a state of being bonded to the movable plate 50. Therefore, the position of the mask metal film 110 remains fixed, which is conducive to reducing the error in the formation position of the first mask pattern P1 and the second mask pattern P2. In addition, the present invention forms the first mask pattern P1 and the second mask pattern P2 in a state where the mask metal film 110 is bonded to the movable plate 50, so that the mask pattern P can be finally formed. While the mask pattern P is formed, the mask 100 is in a state of being supported on the movable plate 50, so that the movable plate 50 can be directly loaded onto the frame 200. It is further conducive to directly using the movable plate 50 in the process of attaching the mask 100 to the frame 200.

[0131] Fig. 9 and Fig.10 FIG. 4 is a schematic diagram of a manufacturing process of a stack of a mask and a moving plate according to another embodiment of the present invention.

[0132] According to Korean Patent Application No. 2019-0146163 Figure 5 and Figure 6 In the prior art, the mask is manufactured in a state where the template is inserted into the template support portion. After the mask is manufactured, the template is separated from the template support portion so that the mask is made to have the same size as the template. However, when the template is inserted into the template support portion, if the gap is inaccurate or the height step difference is inaccurate, there is a problem that an additional alignment process is required. In addition, due to inaccurate gaps and height step differences, the mask cannot be evenly attached to the template and the template support portion, resulting in a problem of poor formation position of the mask pattern.

[0133] Therefore, in the present invention, the template support and the template are not used separately, but only the moving plate 50 is used, the entire surface of the mask metal film 110 is bonded to the moving plate 50, and the mask pattern P is formed, thereby solving the above-mentioned problem.

[0134] In the above Figure 8 During the manufacturing process of the stacked body 20 (20-1) of the mask 100 and the movable plate 50, the movable plate 50 is prepared as a mask unit region CR having an area larger than that of the frame 200. Manufacturing the mask 100 on the movable plate 50 is advantageous in simplifying the process. However, if the movable plate 50 is too large, interference may occur between adjacent movable plates 50 or between components of other frames 200 during the process of aligning the mask 100 to the mask unit region CR of the frame 200.

[0135] Reference Fig. 9, the movable plate 50 can be cut SC in the stacked body 20 (20-1) of the mask 100 and the movable plate 50. By cutting SC, the size of the unit portion C and the dummy portion DM [first dummy portion DM1] of the mask 100 can be obtained. When the movable plate 50 is cut SC, the mask 100 and the dry film resist layer 55 can also be cut SC together.

[0136] The moving plate 50 is made of a material such as borosilicate glass, and can be easily cut SC by using a known scribing method.

[0137] Reference Fig. 9 Referring to the lower figure of FIG. 1 , after SC cutting, a stacked body 20 (20-2) of the mask 100 and the movable plate 50 can be provided, and the size of the mask 100 corresponds to the size of the mask unit region CR. The mask 100 and the movable plate 50 may have the same size and shape. Alternatively, the movable plate 50 and the mask 100 may be cut by the SC process separately, and the size of the movable plate 50 may be larger than the size of the mask 100. However, in order to prevent interference between the above-mentioned movable plates 50, one side needs to have a size larger than the mask 100 by a few mm or less.

[0138] Reference Fig.10 In the upper figure, the movable plate 50' can be prepared as a plurality of mask unit regions CR having an area larger than the frame 200. In this case, a plurality of mask metal films 110 are bonded to the movable plate 50' with a large area at intervals, and the above Figure 5 (d) to Figure 8 (h) process.

[0139] In the stacked body of the plurality of masks 100 and the large-area moving plate 50', the moving plate 50' can be SC cut. When the SC moving plate 50 is cut, the SC masks 100 and the dry film resist layer 55 can also be cut.

[0140] Reference Fig.10 , after cutting SC, the dummy portion of the movable plate 52' between the mask 100 is discarded, and the stacked body 20 (20-2) of the mask 100 and the movable plate 50 can be made of multiple parts, and the size of the mask 100 corresponds to the mask unit region CR.

[0141] According to Korean Patent Application No. 2018-0016186, in the prior art, a through hole for the laser to pass through is processed on a template made of quartz material. The through hole has a smaller diameter for the laser to pass through, so the problem of template breakage may occur during the processing of the through hole. In addition, the holes punched in the quartz material are smaller than a few mm, so the processing difficulty is high and there is a problem of requiring more processing time and processing costs. On the contrary, the movable plate 50 in the present invention uses a material such as borosilicate glass, which allows the laser to pass through without the need to form a through hole separately, and has the effect of significantly reducing processing time and cost. In addition, the movable plate 50 is cut SC by a simple scribing method, which is helpful in solving the breakage problem. In addition, the movable plate 50 is inexpensive, so even if the remaining part is removed by cutting SC, it is also beneficial to save costs compared to the existing process.

[0142] Fig.11 2 is a schematic side cross-sectional view of a process of forming a mask pattern P" (P1", P2") according to a comparative example. Fig.12 is based on Fig.11 A partially enlarged side cross-sectional view of a mask pattern of a mask 100 ″ of a comparative example.

[0143] According to Korean Patent Application No. 2020-0043485, etc. Fig.11 In a comparative example, a liquid wax layer 55" and a photoresist layer 23" may be used on the template 50" and a mask metal film 110" may be bonded. Fig.11 (a) and Fig.11 (b), after the first mask pattern P1" is formed by wet etching for the first time and the second insulating portion M2" is formed, the second mask pattern P2" is formed by wet etching for the second time. A hole SN may be present in a portion of the first mask pattern P1", which penetrates the mask metal film 110" and exposes the underlying photoresist layer 23".

[0144] Reference Fig.11 (a) shows an enlarged portion of the thin mask metal film 110" around the hole SN during the second wet etching WE2. The thin mask metal film 110" around the hole SN cannot be in close contact with the photoresist layer 23" and may have a warped portion FP. The warped portion FP may further warp due to insufficient adhesion of the photoresist layer 23". The wet etching solution WE2' penetrates between the warped portions FP, and the thin portion is removed first. The side of the removed portion is exposed and its side may be further etched. Thus, Fig.11 As shown in (b), the lower portion of the second mask pattern P2" is further etched toward the inner side than the upper portion. Observed from another angle, the side of the second mask pattern P2" may have a positive inclination and a negative inclination. When an arbitrary normal line is generated along the side surface of the second mask pattern P2", the normal line may have a positive slope and a negative slope.

[0145] Reference Fig.12 , the upper width D1" of the first mask pattern P1" is greater than the lower width D2" of the second mask pattern P2". In addition, the lower width D3" of the first mask pattern P1" [or, the upper width D3" of the second mask pattern P2"] is smaller than the lower width D2" of the second mask pattern P2". Therefore, the side surface shape of the mask pattern P" may present a shape similar to the shape of water drops falling on the floor.

[0146] The two side surfaces of the first mask pattern P1" are concave curves, and the two side surfaces of the second mask pattern P2" are convex curves. The lower portion of the second mask pattern P2" is further etched inwardly of the side surface, and the height tc" of the most protruding portion PT" on the side surface of the second mask pattern P2" is at a relatively high position. Assuming that the thickness tb" of the second mask pattern P2" is 1, the height position of the protruding portion PT" is at least greater than 1 / 2 and less than 1.

[0147] The lower portion of the second mask pattern P2" is further etched inwardly of the side surface, and the horizontal distance da" from the lower surface of the second mask pattern P2" to the protruding portion PT" at the end is also relatively large. The angle ta" formed by the virtual straight line connecting the upper corner of the first mask pattern P1" to the protruding portion PT" and the lower surface of the second mask pattern P2" may be approximately less than 60°.

[0148] Figure 13 to Figure 14 FIG. 4 is a schematic side cross-sectional view of a process of forming a mask pattern P according to an embodiment of the present invention. Fig.15 FIG. 1 is a partially enlarged side cross-sectional view of a mask pattern of a mask according to an embodiment of the present invention. Fig.12 The mask pattern P" of the mask 100" of the comparative example is Fig.15 The mask pattern P of the mask 100 of the present invention is compared. Figure 13 to Figure 14 and Figure 6 (f) to Figure 8 This corresponds to the formation process of the mask pattern P described in detail in (h).

[0149] like Fig.13 As shown in (a), a patterned first insulating portion M1 may be formed in the mask metal film 110 .

[0150] Next, if Fig.13 As shown in (b), a mask pattern P1 having a predetermined depth may be formed on the upper portion of the mask metal film 110 by a first wet etching WE1. The first mask pattern P1 may be substantially formed in an arc shape.

[0151] The wet etching WE1 has an isotropic etching characteristic, so the width PA' of the first mask pattern P1 has a different width from the pitch PA between the patterns of the first insulating portion M1, and can have a width greater than the pitch PA between the patterns of the first insulating portion M1. In other words, undercuts (UC) are formed at the lower portions of both sides of the first insulating portion M1, so the width PA' of the first mask pattern P1 can be greater than the pitch PA between the patterns of the first insulating portion M1 by a width equivalent to the formation of the undercut UC.

[0152] Next, if Fig.13 As shown in (c), a second insulating portion M2 may be formed on the mask metal film 110 and the first mask pattern P1.

[0153] Next, if Fig.14 As shown in (d), a second mask pattern P2 penetrating from the first mask pattern P1 to the lower surface of the mask metal film 110 can be formed on the upper portion of the mask metal film 110 by a second wet etching WE2.

[0154] The wet etching WE2 has an isotropic etching characteristic, so the width PB' of the second mask pattern P2 has a different width from the spacing PB between the patterns of the second insulating portion M2, and may have a width greater than the spacing PB between the patterns of the second insulating portion M2. However, the thickness of the second mask pattern P2 is less than 25% of the thickness of the first mask pattern P1, and the degree of side etching during the isotropic etching process is less than that of the first mask pattern P1.

[0155] In addition, the adhesion and etching resistance of the dry film resist 55 of the present invention are better than Fig.11 The liquid wax layer 55" and the photoresist layer 23" of the comparative example. The mask metal film 110 is closely attached to the dry film resist layer 55 by strong adhesive force, so that there is no warping portion FP. Since there is no warping portion FP, the wet etching liquid WE2' can be prevented from entering the interface between the mask metal film 110 and the dry film resist layer 55. Therefore, further side etching can be prevented from occurring at the lower part of the second mask pattern P2. Fig.14 As shown in the enlarged portion of (d), the lower portion of the second mask pattern P2 does not show a further etching toward the inner side of the side surface compared to the upper portion. When viewed from another angle, the side surface of the second mask pattern P2 has a positive slope. When an arbitrary normal line is generated along the side surface of the second mask pattern P2, the normal line has a positive slope.

[0156] Next, if Fig.14 As shown in (e), the process of forming the mask pattern P can be completed by removing the second insulating portion M2.

[0157] Reference Fig.15, the upper width D1 of the first mask pattern P1 is greater than the lower width D2 of the second mask pattern P2. In addition, since the side of the second mask pattern P2 has a positive slope, the lower width of the first mask pattern P1 [or, the upper width of the second mask pattern P2] may be greater than the lower width D2 of the second mask pattern P2.

[0158] Reference Fig.15 In the magnified part on the left side, the two side surfaces of the first mask pattern P1 are concave curves, and the two side surfaces of the second mask pattern P2 (P2-1) are convex curves, close to a straight line, or a straight line. The lower part of the second mask pattern P2 (P2-1) is in a form that is not further etched toward the inner side of the side surface. Therefore, on the side surface of the second mask pattern P2 (P2-1), the height of the most protruding part PT1 may correspond to the lower surface 101 of the second mask pattern P2 (P2-1) (the height is 0). The angle ta formed by the virtual straight line connecting the upper corner of the first mask pattern P1 to the lower corner of the first mask pattern P1 and the lower surface 101 of the second mask pattern P2 (P2-1) is approximately less than 55°, preferably, approximately 45° to 55°.

[0159] Reference Fig.15 In the right enlarged portion, the two side surfaces of the first mask pattern P1 are concave curves, and the two side surfaces of the second mask pattern P2 (P2-2) are convex curves. In this case, the lower portion of the second mask pattern P2 (P2-2) is slightly etched toward the inner side of the side surface. Nevertheless, the mask metal film 110 is tightly attached to the dry film resist layer 55 with a strong adhesive force, thereby significantly reducing the degree of side etching of the lower portion of the second mask pattern P2 (P2-2). Compared with Fig.12 In the comparative example, the height tc of the most protruding portion PT on the side of the second mask pattern P2 (P2-2) is relatively low. Based on the thickness tb of the second mask pattern P2 (P2-2), the height of the protruding portion PT is at least less than 1 / 3 of the thickness tb.

[0160] The lower portion of the second mask pattern P2 (P2-2) is relatively less etched toward the inner side, so the horizontal distance da from the end of the lower surface 101 of the second mask pattern P2 (P2-2) to the protruding portion PT2 is also relatively small. The angle ta" formed by the virtual straight line connecting the upper corner of the first mask pattern P1 of the comparative example to the protruding portion PT" and the lower surface of the second mask pattern P2" is approximately less than 60°. The angle ta formed by the virtual straight line connecting the upper corner of the first mask pattern P1 to the lower corner of the first mask pattern P1 and the lower surface 101 of the second mask pattern P2 (P2-1) may be approximately less than 55°, and preferably, may be approximately 45° to 55°.

[0161] Fig.161 is a schematic diagram of a process of loading a stacked body 20 of a mask 100 and a moving plate 50 onto a frame 200 according to an embodiment of the present invention.

[0162] Reference Fig.16 , the movable plate 50 can be transferred by the vacuum suction cup 90. The vacuum suction cup 90 can be used to suck the opposite side of the movable plate 50 to which the mask 100 is attached and transfer it. The vacuum suction cup 90 can be connected to a moving means (not shown) that moves in the x, y, z, and θ axes. In addition, the vacuum suction cup 90 can also be connected to a flipping means (not shown) that flips the movable plate 50 by sucking it. Fig.16 As shown in (b), during the process in which the vacuum suction cup 90 absorbs the movable plate 50 and then flips over to transfer the movable plate 50 to the frame 200, the bonding state and alignment state of the mask 100 will not be affected.

[0163] Fig.17 1 is a schematic diagram of a state in which the moving plate 50 is loaded onto the frame 200 and the mask 100 is aligned to the unit region CR of the frame 200 according to an embodiment of the present invention.

[0164] Reference Fig.17 , the mask 100 can correspond to one mask unit region CR of the frame 200. The mask 100 can correspond to the mask unit region CR by loading the movable plate 50 onto the frame 200 [or the mask unit sheet portion 220]. Whether the mask 100 corresponds to the mask unit region CR can be observed using a microscope while controlling the position of the movable plate 50 / vacuum suction cup 90. Since the movable plate 50 presses the mask 100, the mask 100 can be closely attached to the frame 200.

[0165] A plurality of movable plates 50 may be loaded onto the frame 200 [or the mask unit sheet portion 220] sequentially or simultaneously so that each mask 100 corresponds to each mask unit region CR. Since the movable plates 50 and the mask 100 have the same size, the movable plates 50 corresponding to a specific mask unit region CR11 and the movable plates 50 corresponding to the adjacent mask unit regions CR12 and CR21 do not interfere / overlap and have a predetermined spacing. The predetermined spacing may be less than 1 / 2 of the width of the first grid sheet portion 223 and the second grid sheet portion 225.

[0166] In addition, the lower support body 70 may be arranged below the frame 200. The lower support body 70 may press the reverse side of the mask unit region CR in contact with the mask 100. At the same time, since the lower support body 70 and the moving plate 50 press the edge of the mask 100 and the frame 200 [or the mask unit sheet portion 220] in opposite directions to each other, the alignment state of the mask 100 may be maintained without distortion.

[0167] Next, laser L is irradiated to the mask 100, and the mask 100 is connected to the frame 200 by laser welding. The laser L may be irradiated to the welding part WP of the mask 100 through the moving plate 50. The welding part WP of the mask 100 welded by laser will generate a welding bead WB, which may have the same material as the mask 100 / frame 200 and be connected as one.

[0168] Fig.18 1 is a partially enlarged side cross-sectional view showing a state in which a welding bead WB is formed in the notch portion RC according to an embodiment of the present invention.

[0169] Reference Fig.18 The welding portion WP of the mask 100 is thicker than other portions of the mask 100, so it is easy to generate welding beads WB, thereby improving welding adhesion.

[0170] In addition, the portion used to form the recessed portion RC may present a step WS. The step WS may be concave with respect to the surface in contact with the target substrate 1900. As an example, the height TW of the step WS may be approximately 5 to 9 μm. The step WS is concave, and when the frame 200 [or the mask unit sheet portion 221, 223] is welded to the mask 100, the weld bead WB generated upward from the bottom portion of the recessed portion RC will not exceed the upper surface [first surface 101] of the mask 100. In other words, the uppermost end of the weld bead WB is lower than or equal to the upper surface [first surface 101] of the mask 100. Therefore, it is possible to prevent the mask 100 from warping up from the target substrate 1900, so that the mask 100 and the target substrate 1900 are in close contact, which has the effect of improving the uniformity of the size and brightness of the OLED pixel 1700.

[0171] Fig.19 FIG. 2 is a schematic diagram of a process of separating the mask 100 from the moving plate 50 after the mask 100 is connected to the frame 200 according to an embodiment of the present invention.

[0172] Reference Fig.19 After the mask 100 is connected to the frame 200, the mask 100 and the movable plate 50 can be separated (debonding). The separation of the mask 100 and the movable plate 50 can be achieved by heating the dry film resist layer 55 ET, chemically treating CM, applying ultrasonic waves US, and applying ultraviolet rays UV. If the dry film resist layer 55 is heated ET, chemically treated CM, applied ultrasonic waves US, and applied ultraviolet rays UV, the adhesive force between the mask 100 and the movable plate 50 becomes weak, and the mask 100 and the movable plate 50 can be separated. After the movable plate 50 is separated, the dry film resist layer 55 remaining on the mask 100 can be removed by cleaning or the like.

[0173] Fig. 20FIG. 2 is a schematic diagram of a state in which a mask 100 is connected to a frame 200 according to an embodiment of the present invention. Fig. 20 The state in which all the masks 100 are attached to the unit region CR of the frame 200 is shown. The masks 100 may be attached one by one and then the movable plate 50 may be peeled off, or all the masks 100 may be attached and then all the movable plates 50 may be peeled off.

[0174] Existing Figure 1 The mask 10 of the present invention has a longer length because it includes six unit parts C1-C6. On the contrary, the mask 100 of the present invention has a shorter length because it includes one unit part C, so the degree of distortion of pixel position accuracy (PPA) may be reduced. In addition, since the present invention only needs to correspond to one unit part C of the mask 100 and confirm the alignment state, it is compared with the existing method that needs to correspond to multiple unit parts C (C1-C6) at the same time and confirm all the alignment states [refer to Figure 1 ], which can significantly shorten the manufacturing time.

[0175] Fig.21 FIG. 1 is a schematic diagram of an OLED pixel deposition apparatus 1000 using a mask and frame connector 10 according to an embodiment of the present invention.

[0176] Reference Fig.21 The OLED pixel deposition device 1000 includes: a magnetic plate 1300 accommodating a magnet 1310 and arranged with a cooling water pipe 1350 ; and a deposition source supply part 1500 supplying an organic source 1600 from the lower part of the magnetic plate 1300 .

[0177] A target substrate 1900 such as glass for depositing the organic source 1600 may be inserted between the magnetic plate 1300 and the deposition source supply unit 1500. A connector 10 (or FMM) of a mask and a frame for depositing the organic source 1600 according to different pixels may be arranged on the target substrate 1900 in a close or very close manner. The magnet 1310 may generate a magnetic field and be closely attached to the target substrate 1900 through the magnetic field.

[0178] The deposition source supply unit 1500 can reciprocate the left and right paths and supply the organic source 1600, and the organic source 1600 supplied by the deposition source supply unit 1500 can be attached to one side of the target substrate 900 through the mask pattern P formed on the connector 10 of the mask and the frame. The organic source 1600 deposited after passing through the mask pattern P of the connector 10 of the mask and the frame can be used as a pixel 1700 of the OLED.

[0179] In particular, the side surface of the second mask pattern P2 of the mask pattern P has a positive slope, and thus has the effect of better preventing uneven deposition of the pixel 1700 caused by the shadow effect. Fig.21 As shown, the organic source 1600 will not be shadowed by the second mask pattern P2, and the OLED pixel 1700 can be deposited in a shape suitable for the width of the second mask pattern P2, and the deposition of the pixel 1700 can be performed with a uniform thickness as a whole.

[0180] The following is an analysis of the effect of the quality of the mask metal film 110 material on the mask and frame connection body 10. Specifically, the mask metal film 110 capable of forming a fine mask pattern P is analyzed from the perspectives of surface defects and inner defects.

[0181] Fig. 22 FIG. 1 is a schematic diagram of a mask metal film 110 ″ according to an embodiment of the present invention.

[0182] As described above, in order to manufacture the mask 100, a process of forming a mask pattern P on the mask metal film 110 is required. The mask pattern P can be formed by etching, etc. In order to form an OLED with a high resolution above UHD, the mask pattern P needs to be formed with a width less than 40 μm, and considering that the mask pattern P has a tapered shape and an inclined shape, the thickness of the mask metal film used needs to be thinned to less than 30 μm.

[0183] In order to finely form the mask pattern P, the shape and direction of the grains in the mask metal film 110" should be considered and etching should be performed. Since the directionality of the grains causes differences in etching rate, if uneven grains are etched, the mask pattern P of the required width cannot be formed. Even an error of several μm can affect the success or failure of high resolution.

[0184] Generally, in a metal sheet produced by rolling, the morphology and orientation of the crystal grains on the surface, that is, the upper and lower surfaces, are different from those in the central portion of the metal sheet. Fig. 22, there are differences in the characteristics of the grains from the upper surface 111" [or, the first to the portion 117" [upper portion 117"] corresponding to the predetermined thickness of the mask metal film 110" and from the lower surface 112" [or, the second surface] to the portion 119" [lower portion 119"] corresponding to the predetermined thickness, compared with the portion corresponding to the central portion 115" other than the upper portion 117" and the lower portion 119". The upper portion 117" and the lower portion 119" have irregular shapes because rolling can arrange the grains longer along the rolling direction. The grains in the central portion 115" are generally non-directional and spherical.

[0185] In order to prevent etching errors caused by differences in the morphology of crystal grains, it is preferred to manufacture the mask 100 by removing the central portion 115" after removing the upper portion 117" and the lower portion 119" of the mask metal film 110". The upper portion 117" and the lower portion 119" may be subjected to thickness reduction processes PS1 and PS2. The thickness reduction processes PS1 and PS2 may also be referred to as planarization processes PS1 and PS2, defect removal processes, and the like. By performing the thickness reduction processes PS1 and PS2, a mask metal film 110 including the central portion 115" may be manufactured. By etching only the central portion 115" where the crystal grains are regularly and evenly arranged and forming a mask pattern P, the width of the mask pattern P can be precisely controlled.

[0186] On this basis, if Fig. 22 When performing the thickness reduction process of the mask metal film 110", surface defects are also carefully considered. The following is explained using the mask metal film of Invar alloy material as an example, and it can also be used on the mask metal film corresponding to the above-mentioned mask material.

[0187] Generally, the manufacturing process of rolled sheet is to first manufacture a raw material ingot [or, raw material Invar alloy] through a melt refining and hot rolling process. The thickness of the Invar alloy sheet can be processed to about 0.5 to 1.0 mm. There are three main factors that cause defects in the raw material Invar alloy. First, the purity of the input raw materials, impurities such as O, C, S, Mn, Cr, etc. in the input raw materials Fe and Ni. Second, impurities such as O, C, N, etc. in the melt refining process are contaminated by the environment of the vacuum melting furnace and the crucible of the melting furnace. Third, internal precipitates formed after high-temperature melting and solidification.

[0188] Then, the raw material Invar alloy can be made into Invar alloy sheets through cold rolling, heat treatment (annealing) and pickling processes. The rolling rate can be controlled at 5 to 20% in each cycle. The thickness of the Invar alloy sheet can be processed from about 0.5 to 1.0 mm to a size of tens of μm, for example, about 20 to 100 μm. There are two causes of defects in the Invar alloy sheet. The first is impurities on the surface of the rolling roller. Impurities on the surface of the superhard alloy roller are adsorbed on the Invar alloy sheet, or exist on the surface in the form of oxides, carbides, nitrides, sulfides, etc. The second is impurities in the rolling process environment. Airborne particles are adsorbed on the Invar alloy sheet and roller.

[0189] Generally, compared with the front-end processes such as melt refining and hot rolling, the back-end processes such as cold rolling, heat treatment and pickling involve more steps, are exposed to the surrounding environment for a longer time, and have a higher possibility of causing defects in the mask metal film.

[0190] Fig.23 FIG. 4 is a schematic diagram of surface defects of a mask metal film according to an embodiment of the present invention. Fig.24 FIG. 4 is a schematic diagram of surface defect types of a mask metal film according to an embodiment of the present invention.

[0191] Reference Fig.23 (a) and Fig.24 ,like Fig.23 (a), the surface of the mask metal film 110' has surface defects SD1 and SD2. Conceptually, surface defects include defects caused by physical damage to the surface due to scratches or corrosion, defects caused by additional formation of particles, impurities, inclusions and other forms of substances, and chemical defects. Most of the defects existing in the above-mentioned Invar alloy sheet are surface defects. As an example, the surface defects may include rolling push marks, scratch defects SD1 (such as dents) and particle defects SD2 (such as oxides, such as SiO2, Al2O3 and foreign particles) caused by the metal film being pushed during the rolling process. Fig.24 Surface defects such as (a) dents, (b) scratches, (c) corrosion, and (d) stains are shown.

[0192] Even after the thickness reduction process of the mask metal film 110', the defects SD1 and SD2 still exist in the central portion 115". Fig.23As shown in (b), when the thickness is thinned by etching WE, there may be a problem of etching along the shape of the scratch defect SD1 (SD1->SD1′->SD1"). In addition, the grain defect SD2 may block the etching WE or cause the etching to be performed at a different ratio and only the periphery of the grain defect SD2 is etched (SD2->SD2'->SD2"->SD2"′). In other words, the surface shapes of the scratch defect SD1 and the grain defect SD2 can be transferred to the center 115" intact.

[0193] In the process of manufacturing the Invar alloy sheet through the above-mentioned cold rolling, annealing and pickling processes, it is difficult to fundamentally prevent the factors causing defects. Therefore, it is necessary to manufacture the mask metal film 110 by performing the thickness reduction process PS1, PS2 [or the flattening process, the defect removal process] for removing these surface defects SD1, SD2.

[0194] Fig.25 FIG. 4 is a schematic diagram of a process for manufacturing a mask metal film according to an embodiment of the present invention.

[0195] Reference Fig.25 (a) The lower surface 112" [second surface] of the mask metal film 110 manufactured by the rolling process can be bonded to the support substrate 40a using the bonding portion 41a. The bonding portion 41a can be made of Figure 4 The adhesive portion 41a may be made of the same material as the adhesive portion 45 described in (a). The adhesive portion 41a may be made of a material such as a dry film resist or liquid wax, which provides temporary adhesion and can be separated by washing.

[0196] After the mask metal film 110" is bonded to the supporting substrate 40a, the thickness reduction process PS1 can be performed while removing surface defects of the upper surface 111" [first surface]. Here, the thickness reduction processes PS1 and PS2 refer to mirroring one side of the mask metal film 110", while removing part of the mask metal film 110" and reducing the thickness. As an example, the thickness reduction processes PS1 and PS2 can be performed using a wet etching method. As another example, the thickness reduction processes PS1 and PS2 can be performed using an etching method such as wet etching and dry etching, and further performed using at least one of lapping, polishing, and buffing. Although lapping, polishing, and buffing have a slower thickness reduction speed, the surface treatment is more refined. Therefore, when used in combination with an etching method with a relatively faster thickness thinning speed, surface defects can be effectively removed and the flatness of the surface of the mask metal film 110" can be improved.

[0197] After the thickness reduction process PS1, the upper layer portion 117" may be removed from the mask metal film 110" while the surface defects may also be removed.

[0198] Then, refer to Fig.25 (b), another support substrate 40b may be prepared, and the upper surface 111" [first surface] of the mask metal film 110' may be bonded to the support substrate 40b using the bonding portion 41b. The support substrate 40b and the bonding portion 41b may be the same as the support substrate 40a and the bonding portion 41a, respectively. Alternatively, the support substrate 40b may correspond to the above-mentioned moving plate 50, and the bonding portion 41b may correspond to the above-mentioned dry film resist layer 55. In this case, Fig.25 Step (b) can also be done with Figure 6 The method is replaced by step (e).

[0199] Then, refer to Fig.25 (c) After the mask metal film 110' is bonded to the support substrate 40b, the support substrate 40a is removed. Next, a thickness reduction process PS2 may be performed on the second surface 112". After the thickness reduction process PS2, the lower layer 119" is removed from the mask metal film 110' and surface defects are also removed.

[0200] Then, refer to Fig.25 (d) When the thickness reduction process PS2 is completed, a mask metal film 110 can be manufactured, and surface defects on both sides of the mask metal film 110 have been removed. The mask metal film 110 includes a central portion 115 ″, and the thickness of the mask metal film 110 can be about 15 μm to 30 μm.

[0201] According to one embodiment, the initial thickness of the mask metal film 110" is approximately 35 to 45 μm, and the thickness of the central portion 115" can be made approximately 15 to 30 μm through thickness thinning processes PS1 and PS2. Assuming that the thickness thinning processes PS1 and PS2 are performed within approximately the same thickness range, the thickness thinned from the upper surface 111" through the thickness thinning process PS1 and the thickness thinned from the lower surface 112" through the thickness thinning process PS2 can be approximately 3 to 13 μm, respectively.

[0202] From another point of view, in order to enable the central portion 115 ″ to use at least a portion of the mask metal film 110 ″ having a thickness between 10% and 90% of the reference thickness, the thickness reduction processes PS1 and PS2 may be performed.

[0203] In addition, it should be noted that Fig.25 The process can not only Figure 4 The process is performed before, but can also be applied to Figure 6 In the planarization process PS described in (e).

[0204] Fig.26The optical microscope photo and the focused ion beam (FIB) photo of the surface defect type of the mask metal film according to one embodiment of the present invention are shown in FIG. The upper part is the optical microscope photo, and the lower part is the focused ion beam photo.

[0205] According to one embodiment, samples of the mask metal film were taken and tested. An Invar sheet with a width of 225 mm was cut on a roller to a size of 205 mm × 205 mm, and samples were prepared. Three areas were sampled and tested. The three areas were the upper left side of the sample (area #1), the middle part (area #2), and the lower right side (area #3), and each area was equivalent to 1 cm × 1 cm. 2 area.

[0206] Fig.26 (a) shows a line type or needle type surface defect with a width of about 3.26 μm. The analysis result of energy dispersive X-ray spectroscopy (EDS) showed that the carbon content was 5.6 wt%. Fig.26 (b) shows a polygonal surface defect with a width of about 4.76 μm. EDS analysis results showed that the defect contained 9 wt% aluminum and 5.4 wt% oxygen. Fig.26 (c) shows an eyeball-shaped or scratch-type surface defect, with a width of about 10.46 μm. EDS analysis results show that the material contains 8.0 wt% manganese and 4.3 wt% sulfur.

[0207] The definition of the surface defects of the mask metal film as described above is a defect on the surface with a length of about 1 μm to 100 μm and a depth of less than 5 μm (greater than 0) along at least one direction. In contrast, surface defects with a smaller length or depth must be removed during the thickness thinning process and will not affect the formation of the mask pattern P. The present invention does not regard such surface defects as surface defects. The surface defects may include inclusions having at least any one of carbon, aluminum oxide, and manganese sulfide. In addition, the surface defects may include inclusions having any one of oxides, carbides, nitrides, and sulfides.

[0208] Fig. 27 The optical microscope photo and the focused ion beam photo of the internal defect type of the mask metal film according to one embodiment of the present invention are shown in FIG. The upper part is the optical microscope photo, and the lower part is the focused ion beam photo.

[0209] Internal defects are defects that exist inside the mask metal film in the thickness direction. They are defects that cannot be seen from the surface. From another point of view, internal defects are defects that remain in the central part 115 of the mask metal film after the thickness reduction process PS1 and PS2 [refer to Fig.23 ] defects. Conceptually, internal defects differ from surface defects only in location. Like surface defects, they include defects caused by physical damage inside due to scratches or corrosion, defects caused by additional particles, impurities, inclusions, and chemical defects. Most of the defects in the above-mentioned raw material, i.e., Invar alloy, are internal defects.

[0210] By adopting Fig.26 The same method is used for the inspection of 1cm 2 area for inspection. Fig. 27 (a) shows a seed type internal defect with a width of about 1.9 μm. EDS analysis results show that the defect contains 5.9 wt% of oxygen. Fig. 27 (b) shows an eyeball-shaped or scratch-type internal defect, with a width of about 1.5 μm. EDS analysis results showed that the material contained 9.1 wt% manganese and 3.9 wt% sulfur.

[0211] The definition of the internal defect of the mask metal film as described above is a defect having a length of about 1 μm to 5 μm in at least one direction on the inside and a depth of less than 2 μm (more than 0). The internal defect may include an inclusion whose composition is an element causing a defect in the raw material, i.e., the Invar alloy, such as any one of O, C, S, Mn, Cr or a compound thereof. In addition, an inclusion having a Fe-Ni oxide composition as a precipitate inside the Invar alloy may also be included.

[0212] Fig.28 It is an analysis curve diagram of surface defects and internal defects in any three regions of the mask metal film according to an embodiment of the present invention.

[0213] against Fig.26 The three areas were analyzed for surface defects and internal defects. The analysis of internal defects was conducted on the defects generated inside after etching with a thickness of 10μm and 20μm. The number of defects and unit area (1cm 2 The analysis results of the number and size of defects of ) are shown in the following table [Table 1]. Fig.28 It is a graph of [Table 1].

[0214] [Table 1]

[0215]

[0216] Refer to [Table 1] and Fig.28 It can be seen that the size of surface defects is about 1 to 30 μm, and the size of internal defects is about 1 to 5 μm. Among surface defects, defects with a size less than 1 μm must be removed during the thickness thinning process and will not affect the formation of the mask pattern. Therefore, they are not considered surface defects.

[0217] For the number of defects per unit area, per cm 2 Can have less than about 50 surface defects per cm 2 There may be about 1 to 15 internal defects. Fig.28 It can be seen from the embodiments that the number of defects per unit area is about 15 to 20 ea / cm 2 , internal defects are about 1 to 2ea / cm 2 .

[0218] From the above, it can be seen that the size and number of surface defects in the defects of the mask metal film (rolled Invar alloy sheet) are significantly larger than those of internal defects, and most of the defects exist on the surface.

[0219] Fig.29 FIG. 4 is a schematic diagram of surface defect removal based on the thickness reduction degree of the mask metal film according to an embodiment of the present invention.

[0220] like Fig.29 The thickness reduction process is performed by etching the surface defects of dent type, line type, and scratch type with a thickness of 1μm, 2μm, and 3μm respectively.

[0221] It was confirmed that the dent type and line type were completely removed by etching at 1 μm. It was confirmed that the scratch type could not be removed by etching at 1 μm, could be partially removed by etching at 2 μm, and could be completely removed by etching at 3 μm.

[0222] Therefore, it can be confirmed that a part of the surface defects can be removed by a thickness reduction process of at least 1 μm. In addition, a thickness reduction process of more than 3 μm can remove all the surface defects. That is, the number of surface defects per unit area is reduced from about 15 to 20 ea / cm before the process. 2 Become 0ea / cm after processing 2. Complete removal of surface defects refers to the situation where some surface defects remain, but the size of these surface defects is not large enough to affect the formation process of the mask pattern. Preferably, surface defects with a length of less than 3μm and a depth of less than 1μm along at least one direction may remain, and more preferably, surface defects with a length of less than 1μm and a depth of less than 1μm along at least one direction may remain. When a thickness thinning process is performed on at least one side of the mask metal film by 3μm to 13μm, all surface defects can be removed, and a mask metal film with a thickness of 15μm to 30μm can be finally obtained.

[0223] In addition, a certain amount of internal defects may still remain after the thickness reduction process. Fig.28 As shown, when the internal defects do not exceed about 3ea / cm 2 When the size of the internal defect is about 1 to 5 μm, it is judged that it will not affect the formation of the mask pattern.

[0224] As described above, the present invention can disclose the physical property standard of the mask metal film, under which the mask metal film has surface and internal quality characteristics that do not affect the formation of the mask pattern. In addition, a fine mask pattern can be uniformly formed by a high-quality mask metal film without surface defects.

[0225] As described above, the present invention has been illustrated and described by way of preferred embodiments, but is not limited to the above embodiments, and those skilled in the art can make various modifications and changes without departing from the spirit of the present invention. Such modifications and changes all fall within the scope of the present invention and the appended claims.

Claims

1. A method for manufacturing a mask metal film, wherein the mask metal film is used to manufacture a mask for forming an OLED pixel, the method comprising the following steps: (a) Preparing a mask metal film made by a rolling process; (b) removing surface defects and reducing thickness on the first surface of the mask metal film; A defect on the first surface of the mask metal film having a length of 1 μm to 100 μm along at least one direction and a depth greater than 0 and less than 5 μm is defined as a surface defect. In the step (b), the surface defects are removed by thinning the thickness of the mask metal film by 3 μm to 13 μm.

2. The method for manufacturing a mask metal film according to claim 1, wherein: Further comprising the steps of: (c) removing surface defects and reducing thickness on a second surface of the mask metal film, which is opposite to the first surface; A defect on the second surface of the mask metal film having a length of 1 μm to 100 μm along at least one direction and a depth greater than 0 and less than 5 μm is defined as a surface defect. In the step (c), the surface defects are removed by thinning the thickness of the mask metal film by 3 μm to 13 μm.

3. The method for manufacturing a mask metal film according to claim 1, wherein: After the step (b), the surface defects on the first surface are completely removed or only the surface defects with a length of less than 1 μm and a depth of less than 1 μm along at least one direction remain.

4. The method for manufacturing a mask metal film according to claim 1, wherein: The step (b) is performed by wet etching.

5. The method for manufacturing a mask metal film according to claim 1, wherein: The step (b) is performed by further utilizing at least one of grinding, polishing, and buffing based on the etching method.

6. The method for manufacturing a mask metal film according to claim 1, wherein: The thickness of the mask metal film in the step (a) is 35 μm to 45 μm.

7. The method for manufacturing a mask metal film according to claim 2, wherein: The thickness of the mask metal film in the step (a) is 35 μm to 45 μm, and after the step (c), the thickness of the mask metal film is 15 μm to 30 μm.

8. The method for manufacturing a mask metal film according to claim 1, wherein: Before the step (b), any 1 cm 2 The number of the surface defects present in the region is greater than 0 and less than 50.

9. The method for manufacturing a mask metal film according to claim 1, wherein: The surface defects include dent type, line type, and scratch type. In the step (b), if the thickness of the mask metal film is reduced by 3 μm, the surface defects of the dent type, the line type, and the scratch type will be removed.

10. The method for manufacturing a mask metal film according to claim 1, wherein: The mask metal film is at least any one of Invar alloy, super Invar alloy, nickel, nickel-cobalt, cobalt, titanium, chromium, tungsten, and molybdenum. The surface defects contain inclusions, and the inclusions contain at least any one of carbon, aluminum oxide, and manganese sulfide.

11. The method for manufacturing a mask metal film according to claim 1, wherein: Taking the thickness direction of the mask metal film as a reference, compared with the portion thinned in the step (b), a defect having a length of 1 μm to 5 μm along at least one direction and a depth greater than 0 and less than 2 μm in a deeper region is defined as an internal defect. After the step (b), any 1 cm on the first surface of the mask metal film 2 The number of said internal defects present in the region is less than 15.

12. The method for manufacturing a mask metal film according to claim 11, wherein: The mask metal film is at least one material selected from the group consisting of Invar alloy, super Invar alloy, nickel, nickel-cobalt, cobalt, titanium, chromium, tungsten and molybdenum, and the internal defects contain at least one component selected from the group consisting of oxide and manganese sulfide of the mask metal film material.

13. A mask metal film for manufacturing a mask for forming OLED pixels, wherein: The mask metal film is made based on a rolling process, and a thickness reduction of 3μm to 13μm is performed on the first surface of the mask metal film to remove surface defects. The surface defects are defined as defects with a length of 1μm to 100μm along at least one direction and a depth greater than 0 and less than 5μm on the first surface of the mask metal film, so that the surface defects on the first surface are completely removed or surface defects with a length of less than 1μm and a depth of less than 1μm along at least one direction remain.

14. The method for manufacturing a mask metal film according to claim 13, wherein: The thickness of the mask metal film is 15 μm to 30 μm. When a defect having a length of 1 μm to 5 μm and a depth greater than 0 and less than 2 μm in at least one direction in a deeper region compared to the thinned portion is defined as an internal defect, any 1 cm on the first surface of the mask metal film 2 The number of said internal defects present in the region is less than 15.

15. A mask metal film used for manufacturing a mask for forming OLED pixels, wherein: The mask metal film is made based on a rolling process, the thickness of the mask metal film is 15 μm to 30 μm, and when a defect with a length of 1 μm to 5 μm along at least one direction and a depth greater than 0 and less than 2 μm is defined as an internal defect, any 1 cm on at least one side of the mask metal film 2 The number of said internal defects present in the region is less than 15.

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