Metal plate, method for manufacturing the same, and method for manufacturing metal mask

Abstract

To provide a metal plate that can improve the positional accuracy of through-holes when a metal mask is installed on a frame, a method for manufacturing the metal plate, as well as the metal mask and a method for manufacturing the metal mask through use of the metal plate.SOLUTION: Provided is a metal plate to be used for manufacturing a metal mask. In a graph in which an arbitrary position n in a width direction of the metal plate is plotted on a horizontal axis and in which a differential expansion rate En in a unit length L0 in a longitudinal direction is plotted on a vertical axis, a maximum inclination of the differential expansion rate E in a central portion in the width direction is 1.8×10 -3 / m or less, and the central portion is a portion that occupies 80% in the width direction excluding both side portions that each occupy 10% in the width direction.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to a metal plate, a method for manufacturing the same, and a method for manufacturing a metal mask.

Background Art

[0002] In recent years, display devices used in portable devices such as smartphones and tablet PCs are required to have high definition, for example, a pixel density of 500 ppi or more. Also, in portable devices, the demand for supporting ultra-high definition (UHD) is increasing. In this case, it is preferable that the pixel density of the display device is, for example, 800 ppi or more.

[0003] Among display devices, organic EL display devices have attracted attention due to their good responsiveness, low power consumption, and high contrast. As a method for forming pixels of an organic EL display device, a method is known in which a metal mask having through holes formed in a desired pattern is used to form pixels in a desired pattern. Specifically, first, a metal mask is adhered to a substrate for an organic EL display device. Next, both the adhered metal mask and the substrate are put into a vapor deposition apparatus, and a vapor deposition process for vapor-depositing an organic material on the substrate is performed. Thereby, pixels containing an organic material can be formed on the substrate in a pattern corresponding to the pattern of the through holes of the metal mask.

[0004] As a method for manufacturing a metal mask, a method of forming through holes in a metal plate by etching using photolithography technology is known. For example, first, a first resist pattern is formed on the first surface of the metal plate by exposure and development processing, and a second resist pattern is formed on the second surface of the metal plate by exposure and development processing. Next, the region of the first surface of the metal plate that is not covered by the first resist pattern is etched to form a first recess on the first surface of the metal plate. Then, the region of the second surface of the metal plate that is not covered by the second resist pattern is etched to form a second recess on the second surface of the metal plate. At this time, by etching so that the first recess and the second recess communicate with each other, a through hole penetrating the metal plate can be formed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, a metal plate for manufacturing a metal mask is manufactured, for example, by rolling a base material made of an iron alloy containing nickel. The thinner the metal plate is rolled, the higher the dimensional accuracy of the through holes of the obtained metal mask becomes. However, on the other hand, a wavy shape appears in the metal plate to some extent due to rolling.

[0007] Since the wavy shape of the metal plate also affects the metal mask to some extent, in the vapor deposition process, a metal mask device in which the metal mask is pulled in the plane direction to be in a state without waves and fixed to a frame is used. Therefore, in order to precisely manufacture an organic EL display device having a high pixel density, the positional accuracy of the through holes when the metal mask is installed on the frame is important.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a metal plate capable of improving the positional accuracy of through holes when a metal mask is installed on a frame, a method for manufacturing the same, and a method for manufacturing a metal mask using the metal plate.

Means for Solving the Problems

[0009] A metal plate according to an embodiment of the present disclosure is a metal plate used for manufacturing a metal mask, in a graph having an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at the unit length L0 in the longitudinal direction as the vertical axis, the maximum slope of the elongation difference rate E at the central portion in the width direction is 1.8×10 -3 / m or less, and the central portion is a portion occupying 80% of the width direction, excluding both side portions occupying 10% of the width direction.

[0010] A method for manufacturing a metal plate according to an embodiment of the present disclosure is a method for manufacturing a metal plate used for manufacturing a metal mask, including a rolling step of rolling a base material to obtain a metal plate, wherein the metal plate in a graph having an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at the unit length L0 in the longitudinal direction as the vertical axis, the maximum slope of the elongation difference rate E at the central portion in the width direction is 1.8×10 -3 / m or less, and the central portion is a portion occupying 80% of the width direction, excluding both side portions occupying 10% of the width direction.

[0011] A method for manufacturing a metal mask according to an embodiment of the present disclosure is a method for manufacturing a metal mask, including a rolling step of rolling a base material to prepare a metal plate, and an etching step of forming the metal mask by etching the metal plate. The metal plate In a graph with an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at the unit length L0 in the longitudinal direction as the vertical axis, The maximum slope of the elongation difference rate E at the central portion in the width direction is 1.8×10 -3 / m or less, The central portion is a portion that occupies 80% of the width direction, excluding both side portions that occupy 10% of the width direction.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a metal plate and a method for manufacturing the same, which can improve the positional accuracy of through holes when a metal mask is installed on a frame, and a method for manufacturing a metal mask using the metal plate.

Brief Description of the Drawings

[0013]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 1E

Figure 1F

Figure 1G

Figure 1H

Figure 1I

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 4E

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings attached to this specification, for the convenience of illustration and easy understanding, the scale, the aspect ratio of the vertical and horizontal dimensions, etc. may be changed and exaggerated appropriately from those of the actual object.

[0015] In this specification and / or in these drawings, unless otherwise specified, the following interpretation shall apply.

[0016] Terms that denote substances that form the basis of a certain configuration do not necessarily have to be distinguished only by different names. For example, terms such as "substrate", "base material", "plate", "sheet", or "film" fall under the above description.

[0017] Terms and / or numerical values that denote shapes and / or geometric conditions do not have to be bound by strict meanings and may be interpreted to include ranges to the extent that similar functions can be expected. For example, "parallel" and / or "orthogonal" etc. fall under the above terms. Also, "length values" and / or "angle values" etc. fall under the above numerical values.

[0018] When a certain configuration is expressed as being "on", "under", "above", "below", "over", or "beneath" another configuration, it may include the mode in which a certain configuration is in direct contact with another configuration and the mode in which another configuration is included between a certain configuration and another configuration. In other words, the mode in which another configuration is included between a certain configuration and another configuration may also be expressed as a certain configuration being in indirect contact with another configuration. Also, the expressions "up", "upper side", or "above" are interchangeable with the expressions "down", "lower side", or "below". In other words, the up-down direction may be reversed.

[0019] When attaching the same reference numeral or similar reference numerals to the same part and / or parts having similar functions, repeated descriptions may be omitted in some cases. Also, the dimensional ratios in the drawings may be different from the actual ratios. Also, a part of the configuration of the embodiment may be omitted from the drawings in some cases.

[0020] One or more forms of the embodiment and one or more forms of the modification may be combined within a range where no contradiction occurs. Also, one or more forms of the embodiment may be combined with each other within a range where no contradiction occurs. Also, one or more forms of the modification may be combined with each other within a range where no contradiction occurs.

[0021] When disclosing a plurality of steps with respect to a method such as a manufacturing method, other steps not disclosed may be carried out between the disclosed steps. Also, within a range where no contradiction occurs, the order of the steps is not limited.

[0022] A numerical range expressed by the symbols “~” and / or “-” includes the numerical values placed before and after the symbols “~” and / or “-”. For example, the numerical range expressed as “34~38 mass%” is the same as the numerical range expressed as “34 mass% or more and 38 mass% or less”.

[0023] Regarding the numerical values described in the present disclosure, a numerical range may be defined by combining any one of a plurality of candidate upper limit values and any one of a plurality of candidate lower limit values. In addition, without particular mention, a numerical range may be defined by combining any two of the plurality of candidate upper limit values, or a numerical range may be defined by combining any two of the plurality of candidate lower limit values.

[0024] One embodiment of the present disclosure is described in the following paragraphs. One embodiment of the present disclosure is an example of the embodiments of the present disclosure. The present disclosure is not construed as being limited to only one embodiment of the present disclosure.

[0025] The metal plate of the present disclosure is a long metal plate used for manufacturing a metal mask. The metal mask can be used for various applications. Although not particularly limited, for example, the metal mask can be used as a metal mask for patterning an organic material on a substrate in a desired pattern in the manufacture of an organic EL display device. The metal mask is also referred to as an evaporation mask. In addition, the metal mask of the present disclosure can enable patterning with a high pixel density. Manufacturable organic EL display devices include displays such as smartphones and televisions, as well as devices for displaying or projecting images and videos for expressing virtual reality (VR) and augmented reality (AR).

[0026] The first aspect of the present disclosure is A metal plate used for manufacturing a metal mask, In a graph with an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at a unit length L0 in the longitudinal direction as the vertical axis, The maximum slope of the elongation difference rate E at the central portion in the width direction is 1.8×10 -3 / m or less, The central portion is a portion occupying 80% of the width direction, excluding both side portions each occupying 10% of the width direction. It is a metal plate.

[0027] A second aspect of the present disclosure is the metal plate according to the first aspect described above, The maximum value of the elongation difference rate En at the central portion in the width direction is 2.5×10 -5 or less.

[0028] A third aspect of the present disclosure is the metal plate according to the first aspect or the second aspect described above, The maximum value of the elongation difference rate En at the side portion is 2.5×10 -5 or more.

[0029] A fourth aspect of the present disclosure is the metal plate according to any one of the first aspect to the third aspect described above, The thickness is 50 μm or less.

[0030] A fifth aspect of the present disclosure is the metal plate according to any one of the first aspect to the fourth aspect described above, wherein the unit length in the longitudinal direction of the metal plate is 0.5 m or more and 3.0 m or less.

[0031] A sixth aspect of the present disclosure is A method for manufacturing a metal plate used for manufacturing a metal mask, including A rolling step of rolling a base material to obtain a metal plate, The metal plate is In a graph with an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at a unit length L0 in the longitudinal direction as the vertical axis, The maximum slope of the elongation difference rate E at the central portion in the width direction is 1.8×10-3 is less than / m, The central part is a part that occupies 80% of the width direction excluding both side parts that occupy 10% of the width direction.

[0032] The seventh aspect of the present disclosure is a rolling process of rolling a base material to prepare a metal plate, an etching process of forming the metal mask by etching the metal plate, and the metal plate In a graph with an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at the unit length L0 in the longitudinal direction as the vertical axis, the maximum slope of the elongation difference rate E in the central part in the width direction is 1.8×10 -3 is less than / m, the central part is a part that occupies 80% of the width direction excluding both side parts that occupy 10% of the width direction, which is a method for manufacturing a metal mask.

[0033] As a premise for explaining the configuration of the metal plate of the present disclosure, first, FIGS. 1A to 1F show an outline of the process of manufacturing the metal mask device 10 from the metal plate 100.

[0034] As shown in FIG. 1A, assume a rolled metal plate 100 that may at least partially have a wavy shape. From the viewpoint of improving the dimensional accuracy of the through holes, the thinner the metal plate is rolled, the more a wavy shape appears in the metal plate due to rolling. Such a wavy shape is caused by the fact that the length of the metal plate 100 in the longitudinal direction D2 varies depending on the position in its width direction D1. Note that the metal plate 100 may have two sides 131 parallel to the width direction D1 and two side edges 130 parallel to the longitudinal direction D2.

[0035] FIG. 1B is a cross-sectional view of the metal plate 100 in FIG. 1A in the longitudinal direction D2. Each cross-sectional view (a) to (d) in FIG. 1B is a cross-sectional view along the a-a line, b-b line, c-c line, and d-d line in FIG. 1A. The a-a line, b-b line, c-c line, and d-d line are all lines parallel to the longitudinal direction D2.

[0036] In the embodiment shown in FIG. 1B, the cross-sectional view (d) passing near the side edge 130 has the largest waves. And as can be seen from the comparison of cross-sectional views (b) to (d), as approaching the center from the side edge 130 in the width direction D1, the waves gradually become smaller. Also, as can be seen from the comparison between cross-sectional view (b) and cross-sectional view (a), the waves are slightly larger in cross-sectional view (a).

[0037] For such a metal plate 100, as shown in FIG. 1C, a first resist film 53a is formed on the first surface 110 of the metal plate 100, and a second resist film 53b is formed on the second surface 120, and then exposed. In this exposure process, the exposure mask is adhered to the first resist pattern 53c and the second resist pattern 53d on the metal plate 100 by means of vacuum adsorption or the like. Therefore, as shown in FIG. 1C, in the exposure process, the wavy shape of the metal plate 100 is compressed, and the metal plate 100 becomes substantially flat.

[0038] In this flattened state, an exposure process is performed and a development process is passed through, so that a predetermined resist pattern is formed so as to define the outer shape of the metal mask 20 at the portion indicated by the dashed line in FIG. 1C. The portion corresponding to the metal mask in the resist pattern may be formed at the central portion 140 where the wavy shape is relatively small. In the present disclosure, the range of ±40% from the center position in the width direction D1 is referred to as the central portion 140, and the range from the end of the central portion 140 to the side edge 130 is referred to as the side portion 150. That is, the central portion 140 is the portion excluding both side portions 150 that occupy 10% of the width direction D1 of the metal plate 100, and the central portion 140 is the portion that occupies 80% of the width direction D1.

[0039] Next, FIG. 1D shows a schematic perspective view of the etching process through the resist pattern. In the etching process, the exposure mask is removed from the metal plate 100, and the corrugated shape is restored to the extent shown in FIG. 1A. Therefore, by performing etching in a state where the corrugated shape is restored as shown in FIG. 1D, the outer shape 27 of the metal mask 20 obtained as shown in FIG. 1E also has a shape that reflects the corrugated shape. Specifically, the outer shape 27 of the metal mask 20 is likely to curve toward the side having a larger corrugated shape (the side closer to the side edge 130).

[0040] Due to the reflection of the distortion caused by the corrugated shape in this way, variations occur in the size of the obtained metal mask 20. As shown in FIG. 1E, such variations can be evaluated by the total pitch mark 28.

[0041] The total pitch mark 28 may be arranged at the corners of each perforated region 22 or in the surrounding region 23 near the corners of each perforated region 22. In the etching process, the total pitch mark 28 may be formed in a concave shape by half-etching at a desired position on the first surface 20a or the second surface 20b, or may be formed as a through-hole. Also, the planar shape of the total pitch mark 28 is not particularly limited, and for example, it may be circular, rectangular, or the like.

[0042] Taking two total pitch marks 28 spaced apart in the longitudinal direction D2 of this total pitch mark 28 as reference points, the linear distance between the two total pitch marks 28 is measured. In this way, by measuring the linear distances TP1 and TP2 of the total pitch marks 28 in the longitudinal direction D2 and obtaining the difference, the distortion of the metal mask 20 can be quantified.

[0043] FIG. 1F shows a schematic view just before the metal mask 20 is installed on the frame 15. As shown in FIG. 1F, when the metal mask 20 is installed on the frame 15, a tension in the longitudinal direction D2 is applied by a clamp 86 or the like. At this time, the tension is applied so that the linear distances TP1 and TP2 of the total pitch marks 28 in the longitudinal direction D2 become substantially the same. Thereby, the metal mask 20 is installed on the frame 15 in a flat state.

[0044] However, the more the shape of each metal mask 20 differs greatly, the more finely the tension adjustment needs to be performed for each metal mask 20 to ensure the positional accuracy. Therefore, even if it has a wavy shape, it is preferable that the variation in the wavy shape is suppressed. Thereby, the positional accuracy of the through holes when the metal mask 20 is installed on the frame 15 can be improved.

[0045] Therefore, in the present disclosure, in a graph having an arbitrary position n in the width direction D1 of the metal plate 100 as the horizontal axis and the elongation difference rate En in the unit length L0 in the longitudinal direction D2 as the vertical axis, the maximum slope of the elongation difference rate E in the central portion 140 in the width direction D1 is 1.8×10 -3 / m or less.

[0046] Thereby, the change in the elongation difference rate En at an arbitrary position n in the width direction D1 of the metal plate 100 becomes small. Thereby, even when a metal mask 20 having an arbitrary width is cut out from the metal plate 100 as shown in FIG. 1E, the difference in the outer shape of each metal mask 20 becomes small, and the quality uniformity is improved. In other words, the metal mask 20 obtained in this way has good positional accuracy of the through holes when installed on the frame 15.

[0047] The maximum slope of the elongation difference rate E of the present disclosure is 1.8×10 -3 / m or less, preferably 1.7×10 -3 / m or less, 1.6×10 -3 / m or less, and may be 1.5×10 -3 / m or less. Also, the maximum slope of the elongation difference rate E is not particularly limited, but is 0 / m or more, and 0.1×10-3 / m or more, 0.2×10 -3 / m or more, 0.3×10 -3 / m or more, 0.4×10 -3 / m or more, 0.5×10 -3 / m or more, 0.6×10 -3 / m or more, 0.7×10 -3 / m or more, 0.8×10 -3 / m or more, 0.9×10 -3 / m or more, 1.0×10 -3 / m or more may be sufficient.

[0048] Furthermore, the maximum slope of the elongation difference ratio E may be determined by any combination of any one of the plurality of lower limit candidate values described above and any one of the plurality of upper limit candidate values described above. As an example of this, the range of the maximum slope of the elongation difference ratio E is 0.1×10 -3 / m or more and 1.8×10 -3 / m or less, 0.2×10 -3 / m or more and 1.7×10 -3 / m or less, 0.3×10 -3 / m or more and 1.6×10 -3 / m or less may be sufficient.

[0049] Hereinafter, with reference to FIGS. 1G to 1I, the “graph with the arbitrary position n in the width direction D1 on the horizontal axis and the elongation difference ratio En at the unit length L0 in the longitudinal direction D2 on the vertical axis” and the “maximum slope of the elongation difference ratio E” will be described in more detail.

[0050] In the present disclosure, the elongation difference ratio En at the unit length L0 in the longitudinal direction D2 with respect to an arbitrary position n in the width direction D1 of the metal plate 100 is measured. That is, the elongation difference ratio En is measured from the wavy shape at an arbitrary position n in the width direction D1, such as the cross-sectional views (a) to (d) shown in FIG. 1B. For example, in FIGS. 1B(a) to (d), as an example, two waves represented by the periods La1 to Ld1, La2 to Ld2 and the heights Ha1 to Hd1, Ha2 to Hd2 are shown for the unit length L0. The number of waves per unit length L0 is not particularly limited and may be one or three or more.

[0051] In the present disclosure, the "unit length L0" represents the length in the longitudinal direction D2 when measuring the elongation difference ratio En of the present disclosure. From the perspective of considering the influence of the elongation difference ratio En on the metal mask 20, the unit length L0 may be approximately the same as the length in the longitudinal direction of the metal mask 20. For example, the unit length L0 may preferably be 0.5 m or more and 3.0 m or less, or may be 1.0 m or more and 1.8 m or less. Further, the unit length L0 may be, for example, 500 mm, 750 mm, 980 mm, 1280 mm, 1648 mm, or 3000 mm. Note that the unit length L0 is the length when the metal plate 100 is viewed in a plan view.

[0052] Note that values related to each elongation difference ratio, such as the maximum slope of the elongation difference ratio E of the present disclosure, the maximum value of the elongation difference ratio En at the central portion, and the maximum value of the elongation difference ratio at both side portions, are preferably satisfied with the above unit length L0, and are preferably satisfied with 750 mm, 1280 mm, and 3000 mm.

[0053] FIG. 1G is a top view of the metal plate 100 of FIG. 1A viewed in a plan view. When viewed from the top view, the metal plate 100 having the unit length L0 actually has a wavy shape as shown in cross-sectional views (a) to (d) of FIG. 1B. Therefore, the length on the surface of the metal plate 100 along the wavy shape is longer than the unit length L0.

[0054] FIG. 1H is a conceptual diagram showing the relationship of the length when the first surface 110 of the metal plate 100 of FIG. 1G is measured in the longitudinal direction D2 at each position n in the width direction. FIG. 1H shows the length Ln on the surface of the metal plate 100 along the wavy shape when measured in the longitudinal direction D2 at the position n in the width direction. The length Ln on the surface of the metal plate 100 along the wavy shape can be said to be the length of the metal plate 100 in the longitudinal direction D2 when the waves are flattened by pulling the metal plate 100 in the longitudinal direction D2.

[0055] Here, the "elongation difference rate" of the present disclosure is a value obtained by the following formula from the minimum value L(min) of Ln and the difference ΔLn between L(min) and Ln. The degree of the wavy shape can be evaluated by the elongation difference rate En. Elongation difference rate En at position n = ΔLn / L(min)

[0056] For example, assume a sample of a metal plate 100 with a width of 500 mm and a length of 1280 mm (unit length L0) in the longitudinal direction. When the surface of this sample is measured in the longitudinal direction D2, assume that the minimum value L(min) is 1280.1352 mm at a position +75 mm from the center. At this time, assume that L is 1280.1612 mm and ΔL is 26.0 μm at a position +0 mm from the center. On this premise, the elongation difference rate E at a position +0 mm from the center is 2.0×10 -5 (= 26.0 μm / 1280.1352 mm) is calculated. Note that the above example is a numerical illustration for explaining the elongation difference rate of the present disclosure and has no relation to the examples of the metal plate and the like of the present disclosure.

[0057] Fig. 1I shows a graph with an arbitrary position n in the width direction D1 on the horizontal axis and the elongation difference rate En at the unit length L0 in the longitudinal direction D2 on the vertical axis. In Fig. 1I, the horizontal axis indicates the position in the width direction D1 of the metal plate 100. From this graph, the elongation difference rate En at each position n in the width direction of the metal plate can be grasped.

[0058] In Fig. 1I, for the metal plate 100 with a width of 500 mm, the horizontal axis shows the center position in the width direction D1 as 0 mm (0%), and the side edges 130 are shown with coordinates of ±250 mm (±50%). Points a to d in Fig. 1I respectively indicate the positions of lines a-a, b-b, c-c, and d-d in the width direction D1. Fig. 1I can illustrate the change in the elongation difference rate En in the width direction D1 of the metal plate 100. As shown in Fig. 1I, a graph showing the change in the elongation difference rate En in the width direction D1 of the metal plate 100, or data showing the change, is also referred to as the "elongation difference rate profile" in the present disclosure.

[0059] Note that point a is located at the center (0 mm [0%]) in the width direction D1 of the metal plate 100. Point d is located on the side edge 130 side (-225 mm [-45%]) in the width direction D1 of the metal plate 100. Also, points b and c are located at the internal division points (-75 mm [-15%], -150 mm [-30%]) that divide the distance between point a and point d into three equal parts. Note that the width of the metal plate 100 in FIG. 1I is merely an example, and the metal plate 100 may have a wider width or a narrower width.

[0060] In the present disclosure, the range from the center position in the width direction D1 ± 40% is referred to as the central portion 140, and the range from the end of the central portion 140 to the side edge 130 is referred to as the side portion 150. That is, the central portion 140 is the portion excluding both side portions 150 that each occupy 10% of the width direction D1 of the metal plate 100, and the central portion 140 is the portion that occupies 80% of the width direction D1. Also, the vertical axis indicates the elongation difference rate En at an arbitrary position n in the width direction D1 of the metal plate 100.

[0061] As one tendency of the elongation difference rate profile, as shown in FIG. 1I, a maximum value of the elongation difference rate En appears near the central portion 140 in the width direction of the metal plate 100 (point a). Also, a minimum value of the elongation difference rate En appears at a position slightly away from the central portion 140 in the width direction of the metal plate 100 to the side edge 130 (point b). Also, as it goes from point b toward the side edge 130 in the width direction D1, the elongation difference rate En increases (point c), and the value of the elongation difference rate En becomes maximum at the side edge 130 in the width direction D1 (point d). However, the shape of the elongation difference rate profile is not limited to this.

[0062] The "maximum slope of the elongation difference rate E" in the present disclosure is the maximum value among the slopes of the central portion 140 of the graph as shown in FIG. 1I. The smaller the maximum slope of the elongation difference rate E, the smaller the change in the large elongation difference rate E in the central portion 140, which means that even when a metal mask 20 of an arbitrary width is cut out from the central portion 140 of the metal plate 100, the difference in the outer shape of each metal mask 20 becomes smaller, and the quality uniformity is improved. In other words, the metal mask 20 obtained in this way has good positional accuracy of the through holes when installed in the frame 15.

[0063] Also, the maximum value of the elongation difference ratio En in the central portion 140 in the width direction D1 is preferably 2.5×10 -5 or less, 2.4×10 -5 or less, 2.3×10 -5 or less, 2.2×10 -5 or less may be sufficient. Note that the position where the elongation difference ratio En is maximum in the central portion 140 in the width direction is not particularly limited. As an example, in the example shown in FIG. 1G, it may be located at point a (0 mm [0%]) or at the boundary between the central portion 140 and the side portion 150 (±200 mm [±40%]).

[0064] The lower limit of the maximum value of the elongation difference ratio En in the central portion 140 in the width direction is not particularly limited, and the smaller the better. As an example, the elongation difference ratio En is 0 or more, 1.0×10 -8 or more, 2.5×10 -8 or more, 5.0×10 -8 or more, 7.5×10 -8 or more, 1.0×10 -7 or more, 2.5×10 -7 or more, 5.0×10 -7 or more, 1.0×10 -6 or more, 2.5×10 -6 or more, 7.5×10 -6 or more, 1.0×10 -5 or more may be sufficient.

[0065] The range of the maximum value of the elongation difference ratio En in the central portion 140 in the width direction may be determined by any combination of any one of the plurality of candidate lower limit values described above and any one of the plurality of candidate upper limit values described above. As such an example, the maximum value of the elongation difference ratio En in the central portion 140 in the width direction is preferably 0 or more and 2.5×10 -5 or less, 1.0×10 -8 or more and 2.4×10 -5 or less, 2.5×10 -8 or more and 2.3×10 -5 or less, 5.0×10 -8 or more and 2.2×10 -5 or less may be sufficient.

[0066] Furthermore, it is preferable that the maximum value of the elongation difference rate En of the two side portions 150 in the width direction D1 is larger than the maximum value of the elongation difference rate En of the central portion 140 in the width direction D1, respectively. As shown in FIG. 1C, it is assumed that the metal plate 100 with a resist film is sandwiched between two exposure masks, and the exposure masks are brought into close contact with the first resist pattern 53c and the second resist pattern 53d on the metal plate 100 by vacuum suction or the like. In this case, since the maximum value of the elongation difference rate En of the side portion 150 is larger than the maximum value of the elongation difference rate En of the central portion 140, an escape path for the air existing in the vicinity of the central portion 140 of the metal plate 100 can be surely secured, and the exposure masks can be sufficiently brought into close contact with the first resist pattern 53c and the second resist pattern 53d over the entire area. Also, when being conveyed, there is a tendency that buckling breakage in which the metal plate 100 bends along its longitudinal direction or deviation such as shifting from the conveyance direction hardly occurs.

[0067] Also, the maximum value of the elongation difference rate En of the two side portions 150 in the width direction D1 is preferably 2.5×10 -5 or more, 3.0×10 -5 or more, 3.5×10 -5 or more, 4.0×10 -5 or more, 4.5×10 -5 or more. Also, the maximum value of the elongation difference rate En of the two side portions 150 is preferably 8.0×10 -5 or less, 7.5×10 -5 or less, 7.0×10 -5 or less, 6.5×10 -5 or less, 6.0×10 -5 or less.

[0068] The range of the maximum value of the elongation difference rate En of the two side portions 150 in the width direction D1 may be determined by any combination of any one of the above-mentioned plurality of lower limit candidate values and any one of the above-mentioned plurality of upper limit candidate values. As such an example, the maximum value of the elongation difference rate En of the two side portions 150 in the width direction D1 is preferably 2.5×10 -5 or more and 8.0×10 -5 or less, 3.0×10-5 7.5×10 or less -5 and 3.5×10 or more -5 7.0×10 or less -5 and 4.0×10 or more -5 6.5×10 or less -5 and 4.5×10 or more -5 6.0×10 or less -5 may be sufficient

[0069] The maximum value of the elongation difference ratio En of the two side portions 150 is preferably 1.8 times or more, 1.9 times or more, 2.0 times or more, 2.1 times or more, 2.2 times or more, 2.3 times or more with respect to the maximum value of the elongation difference ratio En of the central portion 140.

[0070] The maximum value of the elongation difference ratio En of the two side portions 150 is preferably 3.2 times or less, 3.1 times or less, 3.0 times or less, 2.9 times or less, 2.8 times or less, 2.7 times or less with respect to the maximum value of the elongation difference ratio En of the central portion 140.

[0071] Also, the ratio of the maximum value of the elongation difference ratio En of the side portion 150 to the maximum value of the elongation difference ratio En of the central portion 140 may be determined by any combination of any one of the plurality of lower limit candidate values described above and any one of the plurality of upper limit candidate values described above. As such an example, the maximum value of the elongation difference ratio En of the two side portions 150 is preferably 1.8 times or more and 3.2 times or less, 1.9 times or more and 3.1 times or less, 2.0 times or more and 3.0 times or less, 2.1 times or more and 2.9 times or less, 2.2 times or more and 2.8 times or less, 2.3 times or more and 2.7 times or less with respect to the maximum value of the elongation difference ratio En of the central portion 140.

[0072] It is preferable that at least one of the elongation difference ratios En of the two side portions 150 satisfies the above range, and it is more preferable that both satisfy the above range.

[0073] The size in the width direction D1 and the longitudinal direction D2 of the metal plate 100 and the thickness are not particularly limited. The metal plate 100 may be a long metal plate or a short metal plate formed by cutting a long metal plate to a predetermined length or the like.

[0074] The length of the metal plate 100 in the width direction D1 is preferably 200 mm or more, 300 mm or more, 350 mm or more, 400 mm or more, 450 mm or more, and may be 500 mm or more. Also, the length of the metal plate 100 in the width direction D1 is preferably 800 mm or less, 750 mm or less, 700 mm or less, 650 mm or less, 600 mm or less, and may be 550 mm or less. The length of the metal plate 100 in the width direction D1 is preferably 300 mm to 800 mm, 350 mm to 750 mm, 400 mm to 700 mm, and may be 450 mm to 650 mm.

[0075] When the metal plate 100 is short, the total length in the longitudinal direction D2 is preferably 0.5 m or more, 1.0 m or more, and may be 1.2 m or more. When the metal plate 100 is short, the total length in the longitudinal direction D2 is preferably 5.0 m or less, 4.0 m or less, 3.0 m or less, and may be 2.0 m or less. When the metal plate 100 is short, the total length in the longitudinal direction D2 is preferably 0.5 m to 5.0 m, may be 0.5 m to 3.0 m, and may be 1.0 m to 1.8 m.

[0076] When the metal plate 100 is long, the total length in the longitudinal direction D2 is preferably 50 m or more, 100 m or more, 150 m or more, 200 m or more, 300 m or more, 400 m or more, and may be 500 m or more. When the metal plate 100 is long, the total length in the longitudinal direction D2 is preferably 1200 m or less, 1000 m or less, 800 m or less, 700 m or less, 600 m or less. When the metal plate 100 is long, the total length in the longitudinal direction D2 is preferably 50 m to 1200 m, 50 m to 1000 m, 50 m to 800 m, and may be 100 m to 800 m.

[0077] The thickness of the metal plate 100 is preferably 100 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, or 20 μm or less. The thickness of the metal plate 100 is preferably 2.5 μm or more, 5 μm or more, 10 μm or more, or 15 μm or more. The thickness of the metal plate 100 is preferably 2.5 to 100 μm, 5 to 50 μm, or 10 to 40 μm. By reducing the thickness, the porous region 22 of the metal mask 20 described later can be made thinner, and there is a tendency to suppress the adhesion of the vapor deposition material 98 to the second wall surface 36 of the second recess 35 in the vapor deposition process. By increasing the thickness, the strength of the metal mask 20 tends to be further improved. As a result, for example, deformation and breakage of the porous region 22 tend to be more suppressed.

[0078] When reducing the thickness, it is conceivable to increase the rolling ratio in the rolling process of the manufacturing method of the metal plate 100. However, simply increasing the rolling ratio tends to increase the degree of non-uniformity of deformation due to rolling and tends to generate a wavy shape.

[0079] The material constituting the metal plate 100 is not particularly limited, and examples thereof include iron alloys containing nickel, iron alloys containing chromium such as stainless steel, nickel, and nickel-cobalt alloys.

[0080] Among these, iron alloys containing nickel are preferred. By using an iron alloy containing nickel, the thermal expansion coefficient of the metal mask 20 obtained by the metal plate 100 can be made equal to the thermal expansion coefficients of the frame 15 and the substrate 92 (see FIG. 6). As a result, during the vapor deposition process, the occurrence of misalignment due to differences in dimensional changes of the metal mask 20, the frame 15, and the substrate 92 can be suppressed. Therefore, it is possible to suppress a decrease in the dimensional accuracy and positional accuracy of the vapor deposition material 98 adhering to the substrate 92 due to misalignment.

[0081] The ferroalloy containing nickel is not particularly limited. For example, a super-invar material containing cobalt in addition to 30% by mass or more and 34% by mass or less of nickel, an invar material containing 34% by mass or more and 38% by mass or less of nickel, a low thermal expansion Fe-Ni based plating alloy containing 48% by mass or more and 54% by mass or less of nickel, etc., ferroalloys containing 30% by mass or more and 54% by mass or less of nickel can be mentioned.

[0082] Next, the method for manufacturing the metal plate of the present disclosure will be described. The method for manufacturing the metal plate of the present disclosure is a method for manufacturing a metal plate having the maximum value of the slope of the elongation difference rate En, and includes a rolling step of rolling a base material to obtain a metal plate 100, and, if necessary, a slitting step of cutting both ends of the metal plate 100 and an annealing step of heat-treating the metal plate 100 may be included.

[0083] The rolling step is a step of rolling a base material 55 to obtain a metal plate 100. The rolling method is not particularly limited. For example, a method of rolling using a pair of rolling rolls 56a and 56b for rolling the base material 55 in the thickness direction N can be mentioned. The base material 55 is not particularly limited. For example, a ferroalloy containing nickel can be mentioned.

[0084] FIG. 2A shows a schematic cross-sectional view of the rolling step. First, the base material 55 is conveyed in the direction D4 with respect to the rolling rolls 56a and 56b. The base material 55 is rolled by a pair of rolling rolls 56a and 56b. As a result, the thickness of the base material 55 is reduced and it is stretched along the conveyance direction. Thereby, a metal plate 100 is obtained. The metal plate 100 may form a wound body 62 by being wound around a core 61.

[0085] Note that Fig. 2A only shows an overview of the rolling process, and the specific configuration and procedure for implementing the rolling process are not particularly limited. For example, the rolling process may include a hot rolling process of processing the base material at a temperature above the recrystallization temperature of the Invar material constituting the base material 55, or a cold rolling process of processing the base material at a temperature below the recrystallization temperature of the Invar material. Also, in Fig. 2A, it is illustrated that the base material 55 is conveyed in the right direction of the paper surface, but the conveying direction of the base material during rolling is not limited to this, and it may be conveyed in the left direction of the paper surface. Further, the base material 55 may be conveyed back and forth left and right between the rolling rolls 56a and 56b, and rolling may be performed in the process.

[0086] Also, in the rolling process, it may be rolled to the desired thickness at once, or it may be rolled to the desired thickness by performing a plurality of rolling processes at a predetermined rolling ratio. Also, during rolling, rolling oil or the like may be used as necessary.

[0087] From the viewpoint of adjusting the maximum value of the slope of the elongation difference ratio En of the metal plate 100 of the present disclosure and the maximum value of the elongation difference ratio En of the central portion 140 in the width direction, the uniformity of the pressing force fluctuation and the uniformity of the pressing force distribution may be adjusted.

[0088] From the viewpoint of obtaining the metal plate 100 in which the wavy shape is suppressed, it is preferable that the pressing force does not fluctuate and the pressing force is constant. However, the base material may have a partially hard metal structure or a partially thick thickness. Therefore, the pressing force applied to the roll for rolling the base material fluctuates as the base material passes. In order to suppress such a fluctuation of the pressing force, methods such as increasing the number of rolls or providing an adjustment mechanism for keeping the pressing force constant can be mentioned. By maintaining the uniformity of the pressing force fluctuation in this way, there is a tendency that the wavy shape is suppressed.

[0089] From the perspective of obtaining the metal plate 100 with the wavy shape suppressed, the pressing force applied by the roll to the base material is uniform in the width direction, and it is preferable that the pressing force does not vary depending on the location where the roll contacts the base material. However, the base material may have a partially hard metal structure or may be partially thick. Therefore, the pressing force applied to the roll for rolling the base material may become non-uniform in the width direction. In order to suppress such non-uniformity of the pressing force, a method such as providing an adjustment mechanism for keeping the pressing force constant at both ends of the roll can be mentioned. By maintaining the uniformity of the pressing force distribution in this way, the wavy shape tends to be suppressed.

[0090] The slitting process is a process of cutting both ends of the metal plate 100. Thereby, cracks that may occur at both ends of the metal plate 100 due to rolling can be removed. By performing such a slitting process, breakage of the metal plate 100 starting from the cracks, so-called sheet breakage, is suppressed. Further, the slitting process may include cutting off both ends in the width direction of the metal plate 100 over a predetermined range, thereby adjusting the width of the metal plate 100 to a desired width.

[0091] For example, by rolling the base material 55, a metal plate 100 having an overall width exceeding 500 mm, for example, an overall width of 700 mm, may be produced, and then, by cutting both ends in the width direction of the metal plate 100, a metal plate 100 having a width of 500 mm may be produced. At this time, both ends of the metal plate 100 may be cut evenly by 100 mm each, or may be cut unevenly so that the total width of the cut is 200 mm.

[0092] For example, when there is a region with a relatively large elongation difference ratio on one end side of the metal plate 100, the one end side of the metal plate 100 having an overall width of 700 mm may be cut wider than the other end side. Further, when a region with a relatively small elongation difference ratio is shifted from the center to one end side of the metal plate 100, both ends may be cut so that the portion with the small elongation difference ratio becomes the central portion 140 of the 700 mm-wide metal plate 100 after the slitting process.

[0093] The annealing process is a process of heat-treating the metal plate 100. Thereby, the residual stress (internal stress) accumulated by rolling in the metal plate 100 is removed. Although the heat treatment method is not particularly limited, for example, as shown in FIG. 2B, while the metal plate 100 is being conveyed in the direction D5 by roll-to-roll, the metal plate 100 may be heat-treated using the annealing device 57 in the process. Further, at that time, the heat treatment may be performed while pulling the metal plate 100 in the conveying direction (longitudinal direction D2). In addition, in addition, the heat treatment may be performed batchwise in a state where the metal plate 100 is wound around the core 61.

[0094] The annealing process may be carried out in a non-reducing atmosphere or an inert gas atmosphere. Here, the non-reducing atmosphere means an atmosphere substantially free of reducing gases such as hydrogen. "Substantially free of reducing gases" means that the concentration of reducing gases such as hydrogen is 4% or less. The inert gas atmosphere means an atmosphere in which 90% or more of inert gases such as argon gas, helium gas, and nitrogen gas are present. By carrying out the annealing process in a non-reducing atmosphere or an inert gas atmosphere, the formation of nickel hydroxide or the like on the first surface 110 and the second surface 120 of the metal plate 100 can be suppressed.

[0095] The processing conditions of the annealing process can be appropriately set according to the thickness and rolling ratio of the metal plate 100. For example, the processing conditions of the annealing process may be 500°C and 60 seconds.

[0096] The rolling process, the slitting process, and the annealing process may be repeated a plurality of times. Also, at that time, these processes may be performed in any order. According to the method for manufacturing a metal plate of the present disclosure, there is a tendency to obtain a metal plate 100 having high homogeneity over a wider range. In addition, a short metal plate 100 may be produced by cutting the long metal plate 100 configured as described above.

[0097] The metal mask of the present disclosure will be described. In the present specification and drawings, unless otherwise specified, as an embodiment of the present invention, an example of a metal mask used in manufacturing an organic EL display device and a method for manufacturing the same will be described.

[0098] The metal mask 20 of the present disclosure has a perforated region 22 and a peripheral region 23. The perforated region 22 is a region in which a plurality of through-holes 25 are formed. The peripheral region 23 is a region located around the perforated region 22.

[0099] FIG. 3A shows a plan view of the second surface 20b side of the metal mask 20 according to an embodiment of the present disclosure. As shown in FIG. 1, the metal mask 20 may have a substantially rectangular contour in plan view. In the present disclosure, "plan view" means viewing the metal mask 20 from a plane along the plate surface of the metal mask 20.

[0100] FIG. 3B shows an example of a perspective view of the perforated region 22 viewed from the second surface 20b side. FIG. 3C shows a cross-sectional view of the I-I cross section shown in FIG. 3B. FIGS. 3B and 3C are examples in which the second wall surfaces 36 of the second recesses 35 of adjacent through-holes 25 merge on the second surface 20b.

[0101] As shown in FIGS. 3B and 3C, the through-hole 25 has a first recess 30 formed in the first surface 20a, a second recess 35 formed in the second surface 20b, and a circumferential connecting portion 41 connecting the first recess 30 and the second recess 35. The through-hole 25 is such that the first recess 30 on the first surface 20a side and the second recess 35 on the second surface 20b side communicate with each other. And the portion where the first recess 30 and the second recess 35 communicate is the connecting portion 41. The first wall surface 31 of the first recess 30 and the second wall surface 36 of the second recess 35 are connected via the circumferential connecting portion 41.

[0102] The area of the first recess 30 in plan view may gradually decrease from the first surface 20a toward the second surface 20b. Also, the area of the second recess 35 in plan view may gradually decrease from the second surface 20b toward the first surface 20a. Further, the first recess 30 may be configured as a recess having a smaller diameter than the second recess 35.

[0103] Also, in the connecting portion 41, the direction in which the wall surface of the through-hole 25 spreads changes discontinuously. Generally, in the connecting portion 41, the opening area of the through-hole 25 in plan view is minimized.

[0104] Also, FIG. 3D shows another example of a perspective view of the perforated region 22 as viewed from the second surface 20b side. FIG. 3D is an example in which the second wall surfaces 36 of the second recesses 35 of adjacent through-holes 25 do not merge on the second surface 20b.

[0105] The metal mask 20 of the present disclosure has a first surface 20a and a second surface 20b as front and back surfaces. In the present disclosure, the first surface 20a and the second surface 20b of the metal mask 20 are distinguished by the diameters of the through-holes 25 on the front and back surfaces of the perforated region 22. Specifically, as shown in FIG. 3D, the first surface 20a refers to the surface where the opening area of the through-hole 25 is small in the perforated region 22, and the second surface 20b refers to the surface where the range S3 of the through-hole 25 is large. Also, as shown in FIGS. 3B and 3C, etc., when the second wall surfaces 36 of the second recesses 35 of adjacent through-holes 25 merge on the second surface 20b, the range S3 closed by the ridge portion 33 surrounding one through-hole 25 may be regarded as the opening of the through-hole 25. In this case, the range closed by the ridge portion 33 becomes the opening area.

[0106] Also, from the viewpoint of the vapor deposition process, the first surface 20a may be the surface of the metal mask 20 facing the substrate 92 when the metal mask device 10 is accommodated in the vapor deposition device 90 (see FIG. 6). Also, the second surface 20b may be the surface of the metal mask 20 located on the crucible 94 side holding the vapor deposition material 98 when the metal mask device 10 is accommodated in the vapor deposition device 90 (see FIG. 6).

[0107] In the metal mask 20 of the present disclosure, one perforated region 22 may be configured to correspond to one organic EL display device. For example, as shown in FIG. 3A, the metal mask 20 may have a plurality of perforated regions 22 arranged in a row at a predetermined interval along the longitudinal direction D7. Further, it may have a plurality of rows of perforated regions 22 in the width direction D6. In FIG. 3A, the peripheral region 23 is located around each perforated region 22. By using such a metal mask 20, it becomes possible to deposit a plurality of organic EL display devices on a substrate 92 described later.

[0108] The perforated region 22 of the metal mask 20 may have a total pitch mark 28. The total pitch mark 28 is a mark provided for evaluating the positional accuracy and the like between a plurality of through holes 25 in the metal mask 20.

[0109] For example, the total pitch mark 28 may be arranged near the corner of each perforated region 22 and outside the perforated region 22 (that is, in the peripheral region 23), or may be arranged inside the perforated region 22. The total pitch mark 28 may be formed in a concave shape by half etching at a desired position on the first surface 20a or the second surface 20b in the first surface etching step or the second surface etching step described later. Alternatively, a through hole extending from the first surface 20a to the second surface 20b may be formed and used as the total pitch mark 28. Further, in FIG. 3A, an example in which the planar shape of the total pitch mark 28 is circular is shown, but it is not limited thereto, and it may have an arbitrary shape such as a rectangle.

[0110] Note that the "distance TP" shown in FIG. 3A is the distance between the total pitch marks 28 and is the distance between both ends of the perforated regions 22 arranged in the longitudinal direction D7.

[0111] As described later, the metal mask 20 of the present disclosure is obtained by the method for manufacturing a metal mask according to an embodiment of the present disclosure, and thus the positional accuracy and dimensional accuracy of the through holes 25 tend to be good.

[0112] Next, a method for manufacturing a metal mask according to an embodiment of the present disclosure will be described.

[0113] The method for manufacturing a metal mask according to an embodiment of the present disclosure includes a preparation step of preparing a metal plate 100 having a first surface 110 and a second surface 120 located on the opposite side of the first surface 110, and an etching step of forming the metal mask 20 by etching the metal plate 100. As the metal plate 100, the above-described metal plate 100 is used.

[0114] In the following, a method for manufacturing the metal mask 20 by etching will be described. However, the metal mask 20 may be formed by etching or by laser processing.

[0115] The method for manufacturing the metal mask 20 according to an embodiment of the present disclosure will be mainly described with reference to FIGS. 4A to 4F. FIG. 4A is a schematic diagram showing a manufacturing apparatus 70 for manufacturing the metal mask 20 using the metal plate 100 together with its processing sequence. FIG. 4A shows an example in which the metal plate 100 is continuously supplied from a resist film forming apparatus 71 to a peeling apparatus 74. However, the method for manufacturing the metal mask 20 of the present disclosure is not limited thereto. For example, the metal plate 100 may be wound up after being processed by each apparatus to be in a wound state. Further, when supplying the metal plate 100 to each apparatus, the metal plate 100 may be unwound from the wound body and supplied.

[0116] Hereinafter, each step of the method for manufacturing the metal mask 20 will be described in detail.

[0117] First, a metal plate 100 having a desired thickness is prepared (preparation step). The metal plate 100 may be in a state of a wound body 62 wound around a core 61. The method for producing the metal plate 100 having a desired thickness is not particularly limited, and examples thereof include the above-described rolling method and plating film forming method.

[0118] Subsequently, using a resist film forming apparatus 71, resist films 53a and 53b are formed on the first surface 110 and the second surface 120 of the metal plate 100 (FIG. 4B). Specifically, the resist films 53a and 53b may be formed by attaching a dry film resist to the first surface 110 and the second surface 120. Further, the resist films 53a and 53b may be formed by applying a coating solution containing a photosensitive resist material to the first surface 110 and the second surface 120 and drying it.

[0119] The dry film resist and the coating solution are not particularly limited, and conventionally known ones can be used. Further, the resist films 53a and 53b thus formed may be negative resists or positive resists. Among them, a negative resist is preferably used.

[0120] The thickness of the resist films 53a and 53b is preferably 15 μm or less, 10 μm or less, 6 μm or less, and may be 4 μm or less. Further, the thickness of the resist films 53a and 53b is preferably 1 μm or more, 3 μm or more, 5 μm or more, and may be 7 μm or more. The range of the thickness of the resist films 53a and 53b may be determined by any combination of any one of the above-mentioned plurality of upper limit candidate values and any one of the above-mentioned plurality of lower limit candidate values.

[0121] Subsequently, using an exposure and development apparatus 72, the resist films 53a and 53b are exposed and developed. As a result, as shown in FIG. 4C, a first resist pattern 53c can be formed on the first surface 110, and a second resist pattern 53d can be formed on the second surface 120. For example, when a negative resist film is used, a photomask that prevents light from passing through the region to be removed in the resist film may be placed on the resist film, the resist film may be exposed through the photomask, and the resist film may be further developed.

[0122] Subsequently, using the etching apparatus 73, the metal plate 100 is etched using the first resist pattern 53c and the second resist pattern 53d as masks (etching step). The etching step may include a first surface etching step and a second surface etching step.

[0123] Fig. 4D shows a schematic diagram illustrating an example of the first surface etching step in the perforated region 22. In the first surface etching step, the region of the first surface 110 that is not covered by the first resist pattern 53c is etched using an etching solution. At this time, the second surface 120 may be covered with a resin or the like having resistance to the etching solution.

[0124] Erosion progresses on the first surface 110 that is not covered by the first resist pattern 53c by the etching solution (Fig. 4D). As a result, a large number of first recesses 30 are formed on the first surface 110. Note that the etching of the metal plate 100 can proceed isotropically in various directions from the holes of the resist pattern. Therefore, the cross-sectional areas of the first recesses 30 and the second recesses 35 at each position along the thickness direction N of the metal mask 20 become a shape that gradually decreases as it progresses in the thickness direction N from the surface.

[0125] Fig. 4E shows a schematic diagram illustrating an example of the second surface etching step in the perforated region 22. In the second surface etching step, the region of the second surface 120 that is not covered by the second resist pattern 53d is etched using an etching solution. At this time, a film or the like that covered the second surface 120 in the first surface etching step may be peeled off in advance. Also, the first surface 110 may be covered with a resin 54 or the like having resistance to the etching solution.

[0126] Erosion progresses on the second surface 120 that is not covered by the second resist pattern 53d by the etching solution (Fig. 4E). As a result, second recesses 35 are formed on the second surface 120. Then, the first recesses 30 and the second recesses 35 communicate with each other, thereby forming through-holes 25.

[0127] The etching solution is not particularly limited as long as it is a conventionally known one. For example, those containing a ferric chloride solution and hydrochloric acid can be mentioned.

[0128] In the second surface etching step, as shown in FIG. 4E, etching may proceed until the adjacent second recesses 35 are connected. At the location where the adjacent second recesses 35 are connected, the adjacent second recesses 35 merge to form a ridge portion 33. Further, the ridge portion 33 is separated from the second resist pattern 53d, and at the top of the ridge portion 33, erosion by etching also proceeds in the thickness direction N of the metal plate 100. Thereby, the second resist pattern 53d peels off from the metal plate 100. Note that a part of the second surface 120 may remain between the adjacent second recesses 35.

[0129] Furthermore, using a peeling device 74, a resist pattern, a resin 54 having resistance to an etching solution, etc. are peeled off from the metal plate 100. Then, using a separating device 75, a separating step of separating the metal mask 20 made of a sheet-like metal plate from the metal plate 100 by cutting the long metal plate 100 is performed. In this way, the metal mask 20 can be obtained. According to such a manufacturing method of the metal mask 20, since the above-described metal plate 100 is used, there is a tendency to obtain a metal mask excellent in the positional accuracy and dimensional accuracy of the through holes.

[0130] The metal mask device 10 according to an embodiment of the present disclosure includes a frame 15 and the above-described metal mask 20 installed on the frame 15. The metal mask 20 may be installed on the frame 15 with the second surface 20b in contact with the frame 15. FIG. 5 shows a plan view of the metal mask device 10 as viewed from the first surface 20a side of the metal mask 20. FIG. 6 shows a cross-sectional view representing a vapor deposition device.

[0131] The metal mask device 10 of the present disclosure may have a plurality of metal masks 20 attached to one frame (FIG. 5). In this case, the plurality of metal masks 20 may be arranged in the width direction D1 intersecting the longitudinal direction D2 of the metal mask 20. Further, each metal mask 20 may be fixed to the frame 15 at both end portions 23a in the longitudinal direction D2 of the metal mask 20.

[0132] The method of fixing to the frame 15 is not particularly limited, and examples thereof include welding.

[0133] The metal mask device 10 may include a member that is fixed to the frame 15 and partially overlaps the metal mask 20 in the thickness direction N of the metal mask 20. Examples of such a member are not particularly limited, and include, for example, a member that extends in a direction intersecting the longitudinal direction of the metal mask 20 and supports the metal mask 20, a member that overlaps the gap between two adjacent metal masks, and the like.

[0134] Next, a method for manufacturing an organic EL display device using the metal mask 20 according to the present disclosure will be described with reference to FIG. 6. The organic EL display device may be provided in a state where a substrate 92 and a vapor deposition layer including a vapor deposition material 98 provided in a pattern are laminated.

[0135] The method for manufacturing an organic EL display device according to an embodiment of the present disclosure is not particularly limited, and includes, for example, a vapor deposition step of vapor-depositing a vapor deposition material 98 on a substrate such as the substrate 92 using the metal mask 20.

[0136] In the vapor deposition step, first, the metal mask device 10 is arranged so that the metal mask 20 faces the substrate 92. At this time, as shown in FIG. 6, the first surface 20a of the metal mask 20 may face the substrate 92. Here, the substrate 92 is a vapor deposition object such as a glass substrate.

[0137] When the metal mask device 10 is accommodated in the vapor deposition device 90 as shown in FIG. 6, the surface of the metal mask 20 facing the substrate 92 is the first surface 20a, and the surface of the metal mask 20 located on the side of the crucible 94 holding the vapor deposition material 98 is the second surface 20b. Inside the vapor deposition device 90, the metal mask 20 is disposed on the surface of the substrate 92 on the side of the crucible 94. Here, the metal mask 20 and the substrate 92 may be adhered by magnetic force.

[0138] Inside the vapor deposition device 90, a crucible 94 for accommodating the vapor deposition material 98 and a heater 96 for heating the crucible 94 may be disposed below the metal mask device 10. Here, the vapor deposition material 98 may be, for example, an organic light-emitting material. The vapor deposition material 98 in the crucible 94 is vaporized or sublimated by heating from the heater 96. The vaporized or sublimated vapor deposition material 98 adheres to the substrate 92 through the through holes 25 of the metal mask 20. Thereby, the vapor deposition material 98 is formed into a film on the surface of the substrate 92 in a desired pattern corresponding to the positions of the through holes 25 of the metal mask 20. In the vapor deposition process, the inside of the vapor deposition device 90 may be in a vacuum atmosphere.

[0139] When it is desired to deposit different types of vapor deposition materials according to pixels such as RGB, the vapor deposition material 98 may be formed into a film on the surface of the substrate 92 using different metal masks 20 according to the color of the vapor deposition material 98. For example, the vapor deposition material 98 for red, the vapor deposition material 98 for green, and the vapor deposition material 98 for blue may be sequentially deposited on the substrate 92. Further, the metal mask 20 (metal mask device 10) and the substrate 92 may be relatively moved little by little along the arrangement direction (the aforementioned one direction) of the through holes 25, and the vapor deposition material 98 for red, the vapor deposition material 98 for green, and the vapor deposition material 98 for blue may be sequentially deposited.

[0140] In addition to the deposition step of depositing the deposition material 98 on a substrate such as the substrate 92 using the metal mask 20, the method for manufacturing an organic EL display device may include various other steps. For example, the method for manufacturing an organic EL display device may include a step of forming a first electrode on the substrate. The deposition layer is formed on the first electrode. Further, the method for manufacturing an organic EL display device may include a step of forming a second electrode on the deposition layer. Additionally, the method for manufacturing an organic EL display device may include a sealing step of sealing the first electrode, the deposition layer, and the second electrode provided on the substrate 92.

[0141] The deposition layer formed on a substrate such as the substrate 92 using the metal mask 20 is not limited to the light-emitting layer formed by depositing the above-described organic light-emitting material, and may include other layers. For example, the deposition layer may include, in order from the first electrode side, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and the like. In this case, a deposition step using the metal mask 20 corresponding to each layer may be performed. According to the method for manufacturing an organic EL display device of the present disclosure, since the above-described metal mask 20 is used, there is a tendency to obtain an organic EL display device excellent in pixel dimension accuracy and position accuracy.

Example

[0142] Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is not limited by the following examples.

[0143] (First Sample) First, by performing the above-described rolling step, slitting step, and annealing step on a base material composed of an Invar material, a plurality of wound bodies in which a long metal plate was wound were manufactured.

[0144] Specifically, first, a first rolling step of performing a first hot rolling step and a first cold rolling step in this order was carried out. Next, a first slitting step of cutting off both ends in the width direction of the long metal plate over a range of 3 to 5 mm each was performed. Then, a first annealing step of continuously annealing the long metal plate at 500 °C for 60 seconds was carried out.

[0145] Furthermore, a second rolling process including a second cold rolling process was performed on the long metal plate that had undergone the first annealing process. Next, a second slitting process was performed in which both ends in the width direction of the long metal plate were each cut off over a range of 3 to 5 mm, and then, a second annealing process was performed in which the long metal plate was continuously annealed at 500 °C for 60 seconds.

[0146] As a result, a metal plate with a width of 600 mm and having a desired thickness was obtained. Thereafter, both ends in the width direction of the metal plate were each cut off over a predetermined range, and thereby, a slitting process was performed to finally adjust the width of the metal plate to a desired width, specifically, a width of 500 mm.

[0147] Note that the cold rolling process was performed while cooling the metal plate using rolling oil. After the cold rolling process, a cleaning process was performed in which the long metal plate was cleaned with a hydrocarbon-based cleaning agent. After the cleaning process, the above-described slitting process, annealing process, and slitting process were performed. Thereafter, a first sample made of a long metal plate with a width of 500 mm and a length of 600 m was obtained by cutting off the tip of the coil.

[0148] In the measurement, first, as indicated by the arrow in FIG. 1G, a distance measuring device using a laser beam was relatively moved along the longitudinal direction D2 with respect to the first sample, and the height position of the surface of the first sample in the longitudinal direction was continuously measured. By performing this while shifting in the width direction, the height profile of the wavy shape of the first sample was acquired. Then, based on the height profile, a profile of the elongation difference rate En in the unit length L0 in the longitudinal direction with respect to an arbitrary position n in the width direction of the metal plate was obtained.

[0149] Also, the measurement interval of the height profile was set to 8 mm intervals in the width direction D1 and 10 mm intervals in the longitudinal direction D2. The unit length L0 was measured at two different lengths of 750 mm, 1280 mm, and 3000 mm. Note that this unit length L0 (1280 m or 3000 mm) is assumed for a metal mask with a larger product size.

[0150] (Second sample to fifth sample) In the same manner as in the case of the first wound body, the second to fifth wound bodies were manufactured from a base material composed of an inverter material. Further, in the same manner as in the case of the first wound body, the elongation difference ratios of the second to fifth samples taken from each wound body were measured for the second to fifth wound bodies.

[0151] In the case of the second wound body, in the above hot rolling process and cold rolling process, the pressure was adjusted so that the pressing force did not fluctuate relatively as the base material passed through.

[0152] In the case of the third wound body, the pressure was adjusted so that the fluctuation of the pressing force according to the passage of the base material was suppressed more than when manufacturing the second wound body.

[0153] In the case of the fourth wound body, the suppression of the fluctuation of the pressing force according to the passage of the base material was carried out in the same manner as when manufacturing the third wound body, and further, the pressure was adjusted so that the pressing force applied to the base material was relatively uniform in the width direction.

[0154] In the case of the fifth wound body, the suppression of the fluctuation of the pressing force according to the passage of the base material was carried out in the same manner as when manufacturing the third wound body, and further, the pressure was adjusted so that the uniformity of the pressing force in the width direction applied to the base material was improved more than when manufacturing the fourth wound body.

[0155] By suppressing the fluctuation of the pressing force according to the passage of the base material more than when manufacturing the second wound body, in the manufacture of the third wound body, the elongation difference ratio of the central portion could be suppressed to be small as a whole, and the maximum value of the elongation difference ratio of the central portion also became small.

[0156] (Metal mask) Metal masks were respectively produced from the metal plates 100 of the first to fifth wound bodies using the above-described method for manufacturing a metal mask. That is, through holes were formed to obtain a metal mask. Here, a metal mask having a dimension in the width direction D1 of 67 mm and distances between both ends of the perforated region arranged in the longitudinal direction D2 of 750 mm and 1280 mm was produced.

[0157] As shown in FIG. 1F, while applying tension, a vapor deposition mask device was fabricated by installing a metal mask on a frame as shown in FIG. 5. Then, the first surface of the metal mask of the vapor deposition mask device was brought into close contact with a substrate to be vapor deposited made of non-alkali glass having a planar dimension of 900 mm × 1500 mm and a thickness of 0.5 mm. Thereafter, a vapor deposition material made of an organic light-emitting material was vapor deposited on the substrate to be vapor deposited through through holes formed in each metal mask. After removing the vapor deposition mask from the substrate to be vapor deposited, the positional accuracy of the vapor deposition material at the time of stretching the metal mask was evaluated.

[0158] The positional accuracy of the vapor deposition material at the time of stretching the metal mask was evaluated by a two-dimensional coordinate dimension measuring instrument. In the evaluation of the positional accuracy, those with high positional accuracy of the vapor deposition material in each pixel were evaluated as "A", and those with low positional accuracy of the vapor deposition material in each pixel were evaluated as "C".

[0159] Table 1 shows the maximum value of the slope of the elongation difference rate En at the center of the metal plate, the maximum value of the elongation difference rate at the center, the maximum value of the elongation difference rate at both side portions, and the results of the positional accuracy at the time of the above stretching.

[0160]

Table 1

[0161] In Examples 1 and 2, as shown above, the maximum values of the elongation difference rate En at the two side portions in the width direction D1 were each larger than the maximum value of the elongation difference rate En at the center in the width direction D1.

[0162] In addition, in the examples and comparative examples, with the unit length L0 being 500 mm, the maximum value of the slope of the elongation difference rate En at the center of the metal plate was also measured. As a result, overall, the maximum value of the slope of the elongation difference rate En at the center of the metal plate with the unit length L0 being 500 mm was larger than the maximum value of the slope of the elongation difference rate En at the center of the metal plates with the unit lengths L0 being 750 mm, 1280 mm, or 3000 mm. Also, it could not be said that the maximum value of the slope of the elongation difference rate En at the center of the metal plate with the unit length L0 being 750 mm, 1280 mm, or 3000 mm could be predicted from the maximum value of the slope of the elongation difference rate En at the center of the metal plate with the unit length L0 being 500 mm.

[0163] Furthermore, in the examples and comparative examples, with the unit length L0 being 500 mm, the maximum value of the elongation difference rate at the center was also measured. As a result, the maximum value of the slope of the elongation difference rate En at the center of the metal plate with the unit length L0 being 500 mm was sometimes larger and sometimes smaller than the maximum value of the slope of the elongation difference rate En at the center of the metal plates with the unit lengths L0 being 750 mm, 1280 mm, or 3000 mm. This is presumably because by increasing the unit length L0, the degree of the waves shown in FIG. 1A and FIG. 1B included in that unit length L0 is different. Also in this case, it could not be said that the maximum value of the elongation difference rate at the center with the unit length L0 being 750 mm, 1280 mm, or 3000 mm could be predicted from the maximum value of the elongation difference rate at the center of the metal plate with the unit length L0 being 500 mm.

Industrial Applicability

[0164] The present invention has industrial applicability as a metal plate used for manufacturing a metal mask.

Explanation of Signs

[0165] 10… Metal mask device, 15… Frame, 20… Metal mask, 20a… First surface, 20b… Second surface, 22… Perforated region, 23… Peripheral region, 23a… End portion, 23b… Side, 25… Through hole, 27… Outer shape, 28… Total pitch mark, 30… First recess, 31… First wall surface, 33… Ridge portion, 35… Second recess, 36… Second wall surface, 41… Connection portion, 53a… Resist film, 53b… Resist film, 53c… First resist pattern, 53d… Second resist pattern, 54… Resin, 55… Base material, 56a… Rolling roll, 56b… Rolling roll, 57… Annealing device, 61… Core, 62… Winding body, 70… Manufacturing device, 71… Resist film forming device, 72… Exposure and development device, 73… Etching device, 74… Stripping device, 75… Separation device, 86… Clamp, 90… Evaporation device, 92… Substrate, 94… Crucible, 96… Heater, 98… Evaporation material, 100… Metal plate, 110… First surface, 120… Second surface, 130… Side edge, 131… Side, 140… Central portion, 150… Side portion.

Claims

1. A metal plate used for manufacturing a metal mask, in a graph with an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at a unit length L0 in the longitudinal direction as the vertical axis, The maximum slope of the elongation difference ratio E at the central portion in the width direction is 1.8×10 -3 / m or less, wherein the central portion is a portion occupying 80% of the width direction, excluding both side portions each occupying 10% of the width direction, metal plate.

2. The maximum value of the elongation difference ratio En at the central portion in the width direction is 2.5×10 -5 or less. The metal plate according to Claim 1.

3. The maximum value of the elongation difference rate En of the side part is 2.5×10 -5 or more. The metal plate according to Claim 1.

4. The thickness of which is 50 μm or less, The metal plate according to Claim 1.

5. wherein the unit length in the longitudinal direction of the metal plate is 0.5 m or more and 3.0 m or less, The metal plate according to Claim 1.

6. A method for manufacturing a metal plate used for manufacturing a metal mask, comprising a rolling step of rolling a base material to obtain a metal plate, wherein the metal plate, in a graph with an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at a unit length L0 in the longitudinal direction as the vertical axis, wherein the central portion is a portion occupying 80% of the width direction, excluding both side portions each occupying 10% of the width direction, The maximum slope of the elongation difference rate E at the central portion in the width direction is 1.8×10 -3 / m or less, method for manufacturing a metal plate.

7. A method for manufacturing a metal mask, comprising a rolling step of rolling a base material to prepare a metal plate, and an etching step of forming the metal mask by etching the metal plate, wherein the metal plate, in a graph with an arbitrary position n in the width direction of the metal plate as the horizontal axis and the elongation difference rate En at a unit length L0 in the longitudinal direction as the vertical axis, wherein the central portion is a portion occupying 80% of the width direction, excluding both side portions each occupying 10% of the width direction, method for manufacturing a metal mask. ​ The maximum slope of the elongation difference rate E at the central portion in the width direction is 1.8×10 -3 / m or less, ​ ​

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