Metal plate for manufacturing a deposition mask, method for manufacturing a metal plate, deposition mask, method for manufacturing a deposition mask, and deposition mask device including a deposition mask

Abstract

To provide a metal plate constituting a vapor deposition mask capable of suppressing formation of a deformation part caused by reduction of strength of the metal plate during a manufacturing process of the vapor deposition mask.SOLUTION: A metal plate used for manufacturing a vapor deposition mask has a thickness of 30 μm or less. An average cross-sectional area of a crystal grain 51 that is obtained by measuring a crystal gain appearing on a cross-sectional plane of the metal plate using the EBSD method and calculating a measurement result through analysis is 0.5 μm2 or more and 50 μm2 or less. The average cross-sectional area is calculated by analyzing a measurement result obtained by the EBSD method using an area method under a condition that a part with a crystal orientation difference of 5 degrees or more is recognized as a grain boundary 52.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present disclosure relates to a metal plate for manufacturing a deposition mask, a method for manufacturing a metal plate, a deposition mask, a deposition mask manufacturing method, and a deposition mask device including the deposition mask. [Background technology]

[0002] In recent years, there has been a growing demand for high resolution, such as a pixel density of 500 ppi or higher, in display devices used in portable devices like smartphones and tablet PCs. Furthermore, there is increasing demand for support for ultra-high definition (UHD) in portable devices, in which case a pixel density of 800 ppi or higher is preferable for the display device.

[0003] Among display devices, organic EL displays are attracting attention due to their excellent responsiveness, low power consumption, and high contrast. One known method for forming pixels in organic EL displays is to use a deposition mask with through-holes arranged in a desired pattern, thereby forming pixels in the desired pattern. Specifically, first, the deposition mask is placed in close contact with a substrate for the organic EL display device, and then the attached deposition mask and substrate are placed together in a deposition apparatus to perform a deposition process in which organic material is deposited onto the substrate. This makes it possible to form pixels containing organic material on the substrate in a pattern corresponding to the pattern of the through-holes in the deposition mask.

[0004] A known method for manufacturing a deposition mask involves forming through-holes in a metal plate by etching using photolithography. For example, a first resist pattern is first formed on a first surface of the metal plate by exposure and development, and a second resist pattern is then formed on a second surface of the metal plate by exposure and development. Next, areas of the first surface of the metal plate that are not covered by the first resist pattern are etched to form first recesses on the first surface of the metal plate. Thereafter, areas of the second surface of the metal plate that are not covered by the second resist pattern are etched to form second recesses on the second surface of the metal plate. By performing the etching so that the first recesses and the second recesses communicate with each other, through-holes can be formed through the metal plate. Metal plates for manufacturing deposition masks are typically produced by rolling a base material made of a metal such as an iron alloy containing nickel.

[0005] Another known method for manufacturing a deposition mask is to manufacture a deposition mask using a plating process. For example, first, a conductive substrate is prepared. Next, a resist pattern is formed on the substrate with a predetermined gap. This resist pattern is provided at a position where the through-holes of the deposition mask are to be formed. Then, a plating solution is supplied into the gaps in the resist pattern, and a metal layer is deposited on the substrate by electroplating. Then, the metal layer is separated from the substrate, thereby obtaining a deposition mask with a plurality of through-holes formed therein. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5382259 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-234385 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to deposit a deposition material onto a substrate in a desired pattern with high precision, it is preferable that the thickness of the deposition mask is small. On the other hand, if the thickness of the deposition mask is small, the strength of the metal plate constituting the deposition mask decreases, and the metal plate is likely to undergo plastic deformation during the manufacturing process of the deposition mask or during use of the deposition mask.

[0008] The embodiments of this disclosure aim to provide a metal plate that can effectively solve the aforementioned problems. [Means for solving the problem]

[0009] One embodiment of the present disclosure is a metal plate used for manufacturing a deposition mask, the metal plate being made of a rolled material of an iron alloy containing at least nickel and having a thickness of 30 μm or less, wherein crystal grains appearing in a cross section of the metal plate that forms an angle of −10° or more and +10° or less with respect to a plane orthogonal to a rolling direction of the metal plate are measured by an EBSD method and the measurement results are analyzed to calculate an average cross-sectional area of ​​the crystal grains of 0.5 μm or less. 2 More than 50μm 2 The average cross-sectional area is calculated by analyzing the measurement results obtained by the EBSD method using an area method under conditions in which portions where the difference in crystal orientation is 5 degrees or more are recognized as grain boundaries. The total content of nickel and cobalt in the rolled material may be 30 mass% or more and 38 mass% or less.

[0010] One embodiment of the present disclosure is a metal plate used for manufacturing a vapor deposition mask, the metal plate being made of a plating film of an iron alloy containing at least nickel and having a thickness of 30 μm or less, wherein crystal grains appearing in a cross section of the metal plate that forms an angle of −10° or more and +10° or less with respect to a plane orthogonal to a longitudinal direction of the plating film are measured by an EBSD method and the measurement results are analyzed to calculate an average cross-sectional area of ​​the crystal grains of 0.5 μm or more. 2 More than 50μm 2The metal plate may have a nickel and cobalt content of 38% by mass or more and 54% by mass or less, and the average cross-sectional area is calculated by analyzing measurement results obtained by EBSD using an area method under conditions in which portions where the difference in crystal orientation is 5 degrees or more are recognized as grain boundaries.

[0011] In a metal plate according to one embodiment of the present disclosure, the average cross-sectional area of ​​the crystal grains is 2.0 μm 2 It may be more than that.

[0012] The metal plate according to one embodiment of the present disclosure may have a thickness of 13 μm or more.

[0013] One embodiment of the present disclosure is a vapor deposition mask comprising a metal plate and through holes formed in the metal plate, the metal plate being made of a rolled material of an iron alloy containing at least nickel and having a thickness of 30 μm or less, wherein crystal grains appearing in a cross section of the metal plate that forms an angle of −10° or more and +10° or less with respect to a plane orthogonal to a rolling direction of the metal plate are measured by an EBSD method and the measurement results are analyzed to calculate an average cross-sectional area of ​​the crystal grains of 0.5 μm 2 More than 50μm 2 The average cross-sectional area is calculated by analyzing the measurement results obtained by EBSD using an area method under conditions in which a portion where the difference in crystal orientation is 5 degrees or more is recognized as a grain boundary. The total content of nickel and cobalt in the rolled material may be 30 mass % or more and 38 mass % or less.

[0014] One embodiment of the present disclosure is a vapor deposition mask comprising a metal plate and through holes formed in the metal plate, the metal plate being made of a plating film of an iron alloy containing at least nickel and having a thickness of 30 μm or less, wherein crystal grains appearing in a cross section of the metal plate that forms an angle of −10° or more and +10° or less with respect to a plane orthogonal to a longitudinal direction of the plating film are measured by an EBSD method, and the average cross-sectional area of ​​the crystal grains calculated by analyzing the measurement results is 0.5 μm 2 More than 50μm2 The following describes a vapor deposition mask, the average cross-sectional area of ​​which is calculated by analyzing the measurement results obtained by the EBSD method using the area method under the condition that portions with a difference of 5 degrees or more in crystal orientation are recognized as grain boundaries. The total content of nickel and cobalt in the plating film may be 38% by mass or more and 54% by mass or less.

[0015] In a deposition mask according to one embodiment of the present disclosure, the average cross-sectional area of ​​the crystal grains is 2.0 μm 2 It may be more than that.

[0016] In a deposition mask according to one embodiment of the present disclosure, the metal plate may have a thickness of 10 μm or more.

[0017] One embodiment of the present disclosure is a vapor deposition mask apparatus comprising the vapor deposition mask described above and a frame to which the vapor deposition mask is welded.

[0018] One embodiment of the present disclosure is a method for manufacturing a vapor deposition mask, comprising the steps of: preparing the metal plate described above; transporting the metal plate along its longitudinal direction; and processing the metal plate to form through holes.

[0019] One embodiment of the present disclosure is a method for manufacturing a metal plate used to manufacture a vapor deposition mask, comprising a manufacturing step of obtaining a rolled material by a rolling method a metal plate made of an iron alloy containing nickel and having a thickness of 30 μm or less, wherein the crystal grains appearing in the cross-section of the metal plate that forms an angle of -10° to +10° with respect to a plane perpendicular to the rolling direction of the rolled material are measured by the EBSD method, and the average cross-sectional area of ​​the crystal grains calculated by analyzing the measurement results is 0.5 μm 2 More than 50μm 2and the average cross-sectional area is calculated by analyzing the measurement results obtained by the EBSD method using an area method under conditions in which a portion where the difference in crystal orientation is 5 degrees or more is recognized as a grain boundary. The manufacturing process may include a rolling process of rolling a base material, and an annealing process of annealing the rolled base material at a temperature in the range of 500°C to 600°C for 30 to 90 seconds while transporting the rolled base material.

[0020] One embodiment of the present disclosure is a method for manufacturing a metal plate used to manufacture a vapor deposition mask, the method comprising: a manufacturing step of obtaining a plating film from the metal plate made of an iron alloy containing at least nickel and having a thickness of 30 μm or less by a plating method; measuring crystal grains appearing in a cross section of the metal plate that forms an angle of −10° or more and +10° or less with respect to a plane orthogonal to a longitudinal direction of the plating film by an EBSD method; and analyzing the measurement results to calculate an average cross-sectional area of ​​the crystal grains of 0.5 μm or less. 2 More than 50μm 2 and the average cross-sectional area is calculated by analyzing the measurement results obtained by the EBSD method using an area method under conditions in which a portion where the difference in crystal orientation is 5 degrees or more is recognized as a grain boundary. The manufacturing process may include a step of forming a plating film on the surface of a drum while rotating a drum partially immersed in a plating solution, and a step of peeling the plating film from the drum to obtain the metal sheet made of the long plating film. [Effects of the Invention]

[0021] According to the embodiments of the present disclosure, the strength and weldability of a metal plate having a thickness of 30 μm or less are improved. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram showing a vapor deposition apparatus including a vapor deposition mask device according to an embodiment of the present disclosure. [Figure 2] 2 is a cross-sectional view showing an organic EL display device manufactured using the deposition mask device shown in FIG. [Figure 3] This is a plan view showing a vapor deposition mask apparatus according to one embodiment of the present disclosure. [Figure 4] Figure 3 is a partial plan view showing the effective area of ​​the deposition mask. [Figure 5] This is a cross-sectional view along the VV line in Figure 4. [Figure 6] 1A to 1C are diagrams showing a process of rolling a base material to obtain a metal plate having a desired thickness. [Figure 7] FIG. 1 is a diagram showing a process of annealing a metal plate obtained by rolling. [Figure 8] This figure shows a sample containing test pieces extracted from a metal plate. [Figure 9] 10A to 10C are diagrams illustrating an example of a process for adjusting the tilt angle of a sample including a test piece. [Figure 10] This figure shows an example of crystal grains appearing in the cross-section of a test specimen, analyzed based on the measurement results of the EBSD method. [Figure 11] 1A to 1C are schematic diagrams for explaining an example of a method for manufacturing a deposition mask overall. [Figure 12] This figure shows the process of forming a resist pattern on a metal plate. [Figure 13] FIG. 10 is a diagram showing a first surface etching step. [Figure 14] This diagram shows the second surface etching process. [Figure 15] 10A to 10C are diagrams showing steps of removing the resin and the resist pattern from the metal plate. [Figure 16] This figure shows an example of a localized deformation occurring in a metal plate. [Figure 17] 17 is a diagram showing an example of a cross-sectional shape of a deformed portion of the metal plate of FIG. 16. FIG. [Figure 18] 10A to 10C are diagrams illustrating an example of a tensioning step of adjusting the position of the deposition mask with respect to the frame while tension is applied to the deposition mask. [Figure 19A] 10A and 10B are diagrams illustrating a welding process for welding a deposition mask to a frame. [Figure 19B] This figure shows a welded joint formed by the welding process. [Figure 20]FIG. 10 is a diagram showing an example of an undesirable welded portion. [Figure 21] FIG. 21 is an enlarged view of the welded portion of FIG. 20. [Figure 22] FIG. 10 is a diagram showing an example of a preferred welded portion. [Figure 23] FIG. 23 is an enlarged view of the welded portion of FIG. 22. [Figure 24] FIG. 1 is a diagram showing an example of a method for measuring the welding strength of a welded portion. [Figure 25] FIG. 1 is a diagram showing the evaluation results of metal plates according to Examples 1 to 16. [Figure 26] 1 is a scatter diagram showing the thicknesses of the metal plates and the area-average cross-sectional areas of the crystal grains according to Examples 1 to 16. FIG. [Figure 27] FIG. 10 is a diagram showing an example of the distribution of the average cross-sectional area of ​​crystal grains in a plurality of selected metal plates. [Figure 28] FIG. 10 is a diagram showing an example of the distribution of the average cross-sectional area of ​​crystal grains in a plurality of selected metal plates. [Figure 29] FIG. 10 is a diagram showing an example of the distribution of the average cross-sectional area of ​​crystal grains in a plurality of selected metal plates. [Figure 30] 1 is a scatter diagram showing the thicknesses of the metal plates and the number average cross-sectional areas of the crystal grains according to Examples 1 to 16. FIG. [Figure 31] 1 is a diagram showing the correlation between the area-average cross-sectional area and the number-average cross-sectional area of ​​crystal grains in metal plates according to Examples 1 to 16. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] In this specification and these drawings, unless otherwise specified, terms such as "plate," "sheet," and "film" are not distinguished from each other solely on the basis of their names. For example, "plate" is a concept that includes components that could also be called sheets or films. Furthermore, "surface (sheet surface, film surface)" refers to the surface that coincides with the planar direction of the plate-like (sheet-like, film-like) component in question when viewed holistically and broadly. Also, the normal direction used for plate-like (sheet-like, film-like) components refers to the normal direction to the surface (sheet surface, film surface) of the component. Moreover, in this specification and these drawings, unless otherwise specified, terms such as "parallel" and "orthogonal," as well as values ​​of length and angle, which specify shape, geometric conditions, and their degree, shall not be strictly interpreted, but shall include a range that allows for the expectation of similar functionality.

[0024] In this specification and these drawings, when a certain component or region is described as being "on top of (or below)," "upwards (or downwards)," or "upwards (or downwards)" another component or region, unless otherwise specified, this interpretation shall include not only cases where one component is directly in contact with another, but also cases where another component is included between the two components. Furthermore, unless otherwise specified, the terms "up" (or "upwards" or "upper") or "down" (or "downwards" or "downward") may be used, but the direction of up and down may be reversed.

[0025] In this specification and these drawings, unless otherwise specified, identical or similarly functioning parts are denoted by the same or similar reference numerals, and repeated descriptions may be omitted. Furthermore, the dimensional ratios in the drawings may differ from the actual ratios for illustrative purposes, and some components may be omitted from the drawings.

[0026] Unless otherwise specified in this specification and drawings, the present invention may be combined with other embodiments and modifications to the extent that no contradictions arise. Furthermore, other embodiments may be combined with each other, or other embodiments may be combined with modifications to the extent that no contradictions arise. Furthermore, modifications may be combined with each other to the extent that no contradictions arise.

[0027] In this specification and these drawings, unless otherwise specified, when disclosing multiple steps in a method such as a manufacturing method, other steps not disclosed may be performed between the disclosed steps. Furthermore, the order of the disclosed steps is arbitrary as long as it does not create a contradiction.

[0028] In this specification and drawings, unless otherwise specified, a numerical range expressed by the symbol "to" includes the numerical values ​​before and after the symbol "to." For example, the numerical range defined by the expression "34 to 38 mass%" is the same as the numerical range defined by the expression "34 mass% or more and 38 mass% or less."

[0029] In one embodiment of the present specification, an example relating to a deposition mask used to pattern an organic material into a desired pattern on a substrate when manufacturing an organic EL display device and a method for manufacturing the same will be described. However, the application is not limited to this, and the present embodiment can be applied to deposition masks used for various purposes.

[0030] Hereinafter, one embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the embodiment described below is merely one example of the embodiments of the present disclosure, and the present disclosure is not construed to be limited to these embodiments only.

[0031] First, a vapor deposition apparatus 90 for performing a vapor deposition process of depositing a vapor deposition material on a target object will be described with reference to FIG. 1. As shown in FIG. 1, the vapor deposition apparatus 90 may include therein a vapor deposition source (e.g., a crucible 94), a heater 96, and a vapor deposition mask device 10. The vapor deposition apparatus 90 may further include an exhaust means for creating a vacuum atmosphere inside the vapor deposition apparatus 90. The crucible 94 contains a vapor deposition material 98 such as an organic light-emitting material. The heater 96 heats the crucible 94 to evaporate the vapor deposition material 98 under a vacuum atmosphere. The vapor deposition mask device 10 is disposed opposite the crucible 94.

[0032] The deposition mask device 10 will be described below. As shown in FIG. 1, the deposition mask device 10 may include a deposition mask 20 and a frame 15 that supports the deposition mask 20. The frame 15 supports the deposition mask 20 in a state where it is pulled in the direction of its surface to prevent the deposition mask 20 from bending. As shown in FIG. 1, the deposition mask device 10 is placed in a deposition device 90 so that the deposition mask 20 faces a substrate, for example, an organic EL substrate 92, which is an object to which a deposition material 98 is to be attached. In the following description, of the surfaces of the deposition mask 20, the surface facing the organic EL substrate 92 is referred to as a first surface 20a, and the surface opposite the first surface 20a is referred to as a second surface 20b.

[0033] As shown in Figure 1, the deposition apparatus 90 may be equipped with a magnet 93 positioned on the side of the organic EL substrate 92 opposite to the deposition mask 20. By providing the magnet 93, the deposition mask 20 can be attracted to the magnet 93 by magnetic force, allowing the deposition mask 20 to be brought into close contact with the organic EL substrate 92.

[0034] Figure 3 is a plan view showing the deposition mask apparatus 10 as seen from the first surface 20a side of the deposition mask 20. As shown in Figure 3, the deposition mask apparatus 10 may comprise a plurality of deposition masks 20. Each deposition mask 20 may include a pair of long sides 26 and a pair of short sides 27. For example, each deposition mask 20 may have a rectangular shape. Each deposition mask 20 may be fixed to the frame 15, for example, by welding, at the pair of short sides 27 or a portion near them.

[0035] The deposition mask 20 may include a metal plate-shaped substrate having a plurality of through-holes 25 formed therein. The deposition material 98 that evaporates from the crucible 94 and reaches the deposition mask apparatus 10 adheres to the organic EL substrate 92 through the through-holes 25 of the deposition mask 20. This allows the deposition material 98 to be deposited on the surface of the organic EL substrate 92 in a desired pattern corresponding to the positions of the through-holes 25 of the deposition mask 20.

[0036] Figure 2 is a cross-sectional view showing an organic EL display device 100 manufactured using the deposition apparatus 90 of Figure 1. The organic EL display device 100 comprises an organic EL substrate 92 and pixels containing a deposition material 98 arranged in a pattern.

[0037] Furthermore, if it is desired to display multiple colors, separate deposition apparatuses 90 equipped with deposition masks 20 corresponding to each color are prepared, and the organic EL substrate 92 is sequentially fed into each deposition apparatus 90. This allows, for example, the deposition of red organic light-emitting material, green organic light-emitting material, and blue organic light-emitting material onto the organic EL substrate 92 in sequence.

[0038] Incidentally, the vapor deposition process may be performed inside a vapor deposition apparatus 90, which is in a high-temperature atmosphere. In this case, the vapor deposition mask 20, the frame 15, and the organic EL substrate 92 held inside the vapor deposition apparatus 90 are also heated during the vapor deposition process. At this time, the vapor deposition mask 20, the frame 15, and the organic EL substrate 92 exhibit dimensional change behavior based on their respective thermal expansion coefficients. In this case, if the thermal expansion coefficients of the vapor deposition mask 20 or the frame 15 and the organic EL substrate 92 differ significantly, misalignment occurs due to the difference in dimensional change, resulting in a decrease in the dimensional accuracy and positional accuracy of the vapor deposition material deposited on the organic EL substrate 92.

[0039] To solve this problem, it is preferable that the thermal expansion coefficients of the deposition mask 20 and the frame 15 are equivalent to that of the organic EL substrate 92. For example, when a glass substrate is used as the organic EL substrate 92, an iron alloy containing nickel can be used as the main material for the deposition mask 20 and the frame 15. The iron alloy may further contain cobalt in addition to nickel. For example, an iron alloy containing 30% to 54% by mass of nickel and cobalt in total and 0% to 6% by mass of cobalt can be used as the material for the substrate constituting the deposition mask 20. Specific examples of iron alloys containing nickel or nickel and cobalt include Invar material containing 34% to 38% by mass of nickel, Super Invar material containing 30% to 34% by mass of nickel and further containing cobalt, and a low-thermal expansion Fe—Ni-based plating alloy containing 38% to 54% by mass of nickel.

[0040] If the temperatures of the deposition mask 20, frame 15, and organic EL substrate 92 do not reach high temperatures during the deposition process, it is not necessary to make the thermal expansion coefficients of the deposition mask 20 and frame 15 the same as those of the organic EL substrate 92. In this case, materials other than the iron alloys mentioned above may be used as the material constituting the deposition mask 20. For example, iron alloys other than the nickel-containing iron alloys mentioned above, such as chromium-containing iron alloys, may be used. As an example of a chromium-containing iron alloy, an iron alloy commonly referred to as stainless steel can be used. In addition, alloys other than iron alloys, such as nickel or nickel-cobalt alloys, may be used.

[0041] Next, the deposition mask 20 will be described in detail. As shown in Fig. 3, the deposition mask 20 may include a pair of ears (a first ear 17a and a second ear 17b) including a pair of short sides 27 of the deposition mask 20, and a middle portion 18 located between the pair of ears 17a and 17b.

[0042] First, the ear portions 17a and 17b will be described in detail. The ear portions 17a and 17b are parts of the deposition mask 20 that are fixed to the frame 15. In this embodiment, the ear portions 17a and 17b are integrally formed with the intermediate portion 18. Note that the ear portions 17a and 17b may be made of a different material from the intermediate portion 18. In this case, the ear portions 17a and 17b are joined to the intermediate portion 18, for example, by welding.

[0043] (middle part) Next, the intermediate portion 18 will be described. The intermediate portion 18 may include at least one effective area 22 in which a through-hole 25 extending from the first surface 20a to the second surface 20b is formed, and a peripheral area 23 surrounding the effective area 22. The effective area 22 is an area of ​​the deposition mask 20 that faces the display area of ​​the organic EL substrate 92.

[0044] In the example shown in Figure 3, the intermediate section 18 includes a plurality of effective regions 22 arranged at predetermined intervals along the long side 26 of the deposition mask 20. Each effective region 22 corresponds to the display area of ​​one organic EL display device 100. Therefore, the deposition mask apparatus 10 shown in Figure 1 enables multi-face deposition of organic EL display devices 100. In some cases, one effective region 22 may correspond to multiple display areas.

[0045] As shown in Figure 3, the effective region 22 may have, for example, a roughly rectangular shape in a plan view, or more precisely, a roughly rectangular outline in a plan view. Although not shown, each effective region 22 can have various shapes of outlines depending on the shape of the display area of ​​the organic EL substrate 92. For example, each effective region 22 may have a circular outline.

[0046] The effective region 22 will be described in detail below. Figure 4 is a plan view showing an enlarged view of the effective region 22 from the second surface 20b side of the deposition mask 20. As shown in Figure 4, in the illustrated example, the multiple through holes 25 formed in each effective region 22 are arranged at a predetermined pitch along two mutually orthogonal directions within the effective region 22.

[0047] FIG. 5 is a cross-sectional view of the effective area 22 of FIG. 4 along the VV direction. As shown in FIG. 5, a plurality of through holes 25 penetrate from a first surface 20a, which is one side of the deposition mask 20 in the normal direction N, to a second surface 20b, which is the other side of the deposition mask 20 in the normal direction N. In the illustrated example, as will be described in detail later, a first recess 30 is formed by etching on a first surface 64a of a metal plate 64, which is one side of the deposition mask 20 in the normal direction N, and a second recess 35 is formed on a second surface 64b of the metal plate 64, which is the other side of the deposition mask 20 in the normal direction N. The first recess 30 is connected to the second recess 35, so that the second recess 35 and the first recess 30 communicate with each other. The through hole 25 is composed of the second recess 35 and the first recess 30 connected to the second recess 35. 4 and 5, the wall surface 31 of the first recess 30 and the wall surface 36 of the second recess 35 are connected via a circumferential connecting portion 41. The connecting portion 41 defines a through portion 42 in which the opening area of ​​the through hole 25 is minimized in a plan view of the deposition mask 20.

[0048] As shown in Figure 5, on the first surface 20a side of the deposition mask 20, two adjacent through holes 25 are spaced apart from each other along the first surface 64a of the metal plate 64. On the second surface 20b side of the deposition mask 20, two adjacent second recesses 35 may also be spaced apart from each other along the second surface 64b of the metal plate 64. That is, the second surface 64b of the metal plate 64 may remain between two adjacent second recesses 35. In the following description, the portion of the effective area 22 of the second surface 64b of the metal plate 64 that remains unetched will also be referred to as the top portion 43. By manufacturing the deposition mask 20 so that such a top portion 43 remains, the deposition mask 20 can be given sufficient strength. This makes it possible to suppress damage to the deposition mask 20, for example, during transport. However, if the width β of the top portion 43 is too large, shadows may occur during the deposition process, which may reduce the utilization efficiency of the deposition material 98. Therefore, it is preferable that the deposition mask 20 be manufactured so that the width β of the top portion 43 does not become excessively large. Shadow refers to the phenomenon in which the deposition material adheres to the region of the deposition target object, such as the organic EL substrate 92, that overlaps with the through-holes of the deposition mask 20, and this adhesion is inhibited by the second surface 20b or the walls of the deposition mask 20.

[0049] 1 is housed in the deposition mask device 90, the first surface 20a of the deposition mask 20 faces the organic EL substrate 92, and the second surface 20b of the deposition mask 20 faces the crucible 94 holding the deposition material 98, as indicated by the two-dot chain line in FIG. 5. Therefore, the deposition material 98 passes through the second recess 35, the opening area of ​​which gradually decreases, and adheres to the organic EL substrate 92. As indicated by the arrow pointing from the second surface 20b toward the first surface 20a in FIG. 5, the deposition material 98 moves from the crucible 94 toward the organic EL substrate 92 not only along the normal direction N of the organic EL substrate 92 but also in a direction significantly inclined relative to the normal direction N of the organic EL substrate 92. In this case, if the thickness of the deposition mask 20 is large, the deposition material 98 moving obliquely is likely to get caught on the top portion 43, the wall surface 36 of the second recess 35, and the wall surface 31 of the first recess 30. As a result, a large proportion of the deposition material 98 does not pass through the through-holes 25. Therefore, in order to improve the utilization efficiency of the deposition material 98, it is preferable to reduce the thickness t of the deposition mask 20, thereby reducing the height of the wall surface 36 of the second recess 35 and the wall surface 31 of the first recess 30. In other words, it is preferable to use a metal plate 64 having as small a thickness t as possible as long as the strength of the deposition mask 20 can be ensured as a metal plate 64 for forming the deposition mask 20. In consideration of this, in this embodiment, the thickness t of the deposition mask 20 is, for example, 30 μm or less, preferably 25 μm or less, and more preferably 20 μm or less. The thickness t of the deposition mask 20 may be 18 μm or less, or may be 15 μm or less. On the other hand, if the thickness of the deposition mask 20 is too small, the strength of the deposition mask 20 decreases, and the deposition mask 20 becomes more susceptible to damage or deformation. In consideration of this, the thickness t of the deposition mask 20 may be 5 μm or more, 7 μm or more, 10 μm or more, 13 μm or more, or 15 μm or more. The thickness t is the thickness of the peripheral region 23, that is, the thickness of the portion of the deposition mask 20 where the first recesses 30 and the second recesses 35 are not formed. Therefore, it can also be said that the thickness t is the thickness of the metal plate 64.

[0050] The thickness t of the deposition mask 20 may be determined by any combination of one of the above-mentioned upper limit candidate values ​​and any one of the above-mentioned lower limit candidate values. For example, the thickness t of the deposition mask 20 may be 5 μm or more and 30 μm or less, 7 μm or more and 25 μm or less, 10 μm or more and 20 μm or less, or 13 μm or more and 18 μm or less. Alternatively, the thickness t of the deposition mask 20 may be determined by any combination of two of the above-mentioned upper limit candidate values. For example, the thickness t of the deposition mask 20 may be 25 μm or more and 300 μm or less. Alternatively, the thickness t of the deposition mask 20 may be determined by any combination of two of the above-mentioned lower limit candidate values. For example, the thickness t of the deposition mask 20 may be 5 μm or more and 7 μm or less.

[0051] In Figure 5, the minimum angle that a straight line L1 passing through the connection portion 41, which is the part of the through-hole 25 with the smallest opening area, and any other arbitrary position on the wall surface 36 of the second recess 35, makes with respect to the normal direction N of the deposition mask 20 is represented by the symbol θ1. In order to allow the diagonally moving deposition material 98 to reach the organic EL substrate 92 as far as possible without reaching the wall surface 36, it is advantageous to increase the angle θ1. In addition to reducing the thickness t of the deposition mask 20, it is also effective to reduce the width β of the top portion 43 as described above in order to increase the angle θ1.

[0052] In Figure 5, the symbol α represents the width of the portion of the first surface 64a of the metal plate 64 that remains unetched (hereinafter also referred to as the rib portion). The width α of the rib portion and the dimension r of the through portion 42 are appropriately determined according to the dimensions and number of display pixels of the organic EL display device. For example, the width α of the rib portion is 5 μm or more and 40 μm or less, and the dimension r of the through portion 42 is 10 μm or more and 60 μm or less.

[0053] The width α of the rib portion may be 10 μm or more, 15 μm or more, or 20 μm or more. Furthermore, the width α of the rib portion may be 35 μm or less, 30 μm or less, or 25 μm or less. The range of the width α of the rib portion may be determined by any combination of one of the above-mentioned upper limit candidate values ​​and any one of the above-mentioned lower limit candidate values. For example, the width α of the rib portion may be 10 μm or more and 35 μm or less, 15 μm or more and 30 μm or less, or 20 μm or more and 25 μm or less. Furthermore, the range of the width α of the rib portion may be determined by any combination of two of the above-mentioned upper limit candidate values. For example, the width α of the rib portion may be 35 μm or more and 40 μm or less. Furthermore, the range of the width α of the rib portion may be determined by any combination of two of the above-mentioned lower limit candidate values. For example, the width α of the rib portion may be 5 μm or more and 10 μm or less.

[0054] The dimension r of the through-hole 42 may be 15 μm or more, 20 μm or more, 25 μm or more, or 30 μm or more. The lower limit of the dimension r of the through-hole 42 may be less than the 10 μm mentioned above. For example, the dimension r of the through-hole 42 may be 5 μm or more. The dimension r of the through-hole 42 may also be 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, or 35 μm or less. The range of the dimension r of the through-hole 42 may be determined by any one of the above-mentioned upper limit candidate values ​​and any one of the above-mentioned lower limit candidate values. For example, the dimension r of the through-hole 42 may be 15 μm or more and 55 μm or less, 20 μm or more and 50 μm or less, 25 μm or more and 45 μm or less, 30 μm or more and 40 μm or less, or 30 μm or more and 35 μm or less. Furthermore, the range of the dimension r of the through-hole 42 may be determined by any two combinations of the above-mentioned multiple upper limit candidate values. For example, the dimension r of the through-hole 42 may be 55 μm or more and 60 μm or less. Also, the range of the dimension r of the through-hole 42 may be determined by any two combinations of the above-mentioned multiple lower limit candidate values. For example, the dimension r of the through-hole 42 may be 5 μm or more and 10 μm or less.

[0055] In Figures 4 and 5, examples are shown in which the second surface 64b of the metal plate 64 remains between two adjacent second recesses 35, but the process is not limited to this. Although not shown, etching may be performed so that two adjacent second recesses 35 are connected. In other words, there may be areas between two adjacent second recesses 35 where the second surface 64b of the metal plate 64 does not remain.

[0056] Next, a method for manufacturing the deposition mask 20 will be described.

[0057] First, a method for manufacturing a metal plate used to manufacture a deposition mask will be described. In this embodiment, an example will be described in which the metal plate is made of a rolled material of an iron alloy containing nickel. The rolled material may have a thickness of 30 μm or less. The rolled material may also contain 30 mass % or more and 38 mass % or less of nickel, 0 mass % or more and 6 mass % or less of cobalt, the balance being iron and unavoidable impurities.

[0058] First, iron, nickel, and other raw materials are prepared. For example, the raw materials are prepared so that the iron and nickel ratios relative to the total raw materials are approximately 64% by weight and approximately 36% by weight, respectively. Next, the raw materials are crushed as needed, and then a melting process is carried out in which the raw materials are melted in a melting furnace. For example, the raw materials are melted and mixed using gas discharge such as arc discharge. This process allows the base material for the metal plate to be obtained.

[0059] The melting temperature is set depending on the raw materials, but is, for example, 1500°C or higher. The melting step may include a step of introducing aluminum, manganese, silicon, etc. into the melting furnace for deoxidation, dehydration, denitrification, etc. The melting step may also be carried out under a low-pressure state lower than atmospheric pressure and in an inert gas atmosphere such as argon gas.

[0060] After removing the base material from the melting furnace, a grinding step may be carried out to scrape off the surface of the base material. This allows oxide coatings such as scale to be removed. The specific grinding method is not particularly limited, but may be a so-called grinding method in which the surface of the base material is scraped by rotating a grinding wheel, or a so-called pushing method in which the surface of the base material is scraped by forcing the base material into a cutting tool. The grinding step may be carried out so that the thickness of the base material is uniform.

[0061] Next, as shown in FIG. 6, a rolling process is performed to roll a base material 60 made of an iron alloy containing nickel. For example, the base material 60 is conveyed toward a rolling mill 66 including a pair of rolling rolls (work rolls) 66a, 66b while applying a tensile force in the direction indicated by arrow D1. The base material 60 that arrives between the pair of rolling rolls 66a, 66b is rolled by the pair of rolling rolls 66a, 66b. As a result, the thickness of the base material 60 is reduced and the base material 60 is stretched along the conveying direction. This allows a metal plate 64 having a predetermined thickness to be obtained. As shown in FIG. 6, the metal plate 64 may be wound around a core 61 to form a wound body 62.

[0062] Note that FIG. 6 merely illustrates an outline of the rolling process, and the specific configuration and procedures for performing the rolling process are not particularly limited. For example, the rolling process may include a hot rolling process in which the base material 60 is processed at a temperature equal to or higher than the temperature at which the crystal orientation of the iron alloy constituting the base material 60 changes, or a cold rolling process in which the base material is processed at a temperature lower than the temperature at which the crystal orientation of the iron alloy changes. Furthermore, the direction in which the base material 60 or the metal plate 64 is passed between the pair of rolling rolls 66a, 66b is not limited to one direction. For example, in FIGS. 6 and 7, the base material 60 or the metal plate 64 may be gradually rolled by repeatedly passing the base material 60 or the metal plate 64 between the pair of rolling rolls 66a, 66b from left to right and from right to left on the paper.

[0063] In the rolling process, the size of the crystal grains contained in the metal plate 64 can be adjusted by adjusting the reduction rate. For example, by increasing the reduction rate, the size of the crystal grains contained in the metal plate 64 can be reduced. In order to reduce the size of the crystal grains, it is preferable to set the reduction rate to the maximum value. Furthermore, by decreasing the reduction rate, the size of the crystal grains contained in the metal plate 64 can be increased.

[0064] The rolling reduction is calculated by the following formula. Rolling reduction rate (%)=((T1-T2) / T1)×100 T1 is the thickness of the metal plate 64 before the rolling process is performed, and T2 is the thickness of the metal plate 64 after the rolling process is performed.

[0065] The rolling reduction of the metal plate 64 in the rolling process is preferably 70% or more. As a result, as will be described later, the average cross-sectional area of ​​the crystal grains of the metal plate 64 is reduced to 50 μm 2 The following is possible: The reduction ratio of the metal sheet 64 in the rolling process may be 75% or more, 80% or more, or 85% or more. Furthermore, the reduction ratio of the metal sheet 64 in the rolling process is preferably 95% or less. This allows the average cross-sectional area of ​​the crystal grains of the metal sheet 64 to be 50 μm², as will be described later. 2 The reduction ratio of the metal plate 64 in the rolling process may be 90% or less, or may be 85% or less.

[0066] The range of the reduction rate of the metal sheet 64 in the rolling process may be determined by a combination of any one of a plurality of upper limit candidate values ​​and any one of a plurality of lower limit candidate values. For example, the reduction rate may be 70% or more and 95% or less, 75% or more and 90% or less, or 80% or more and 85% or less. The range of the reduction rate of the metal sheet 64 in the rolling process may also be determined by a combination of any two of a plurality of upper limit candidate values. For example, the reduction rate may be 90% or more and 95% or less. The range of the reduction rate of the metal sheet 64 in the rolling process may also be determined by a combination of any two of a plurality of lower limit candidate values. For example, the reduction rate may be 70% or more and 75% or less.

[0067] In the rolling process, the rolling speed, i.e., the conveying speed of the metal sheet 64, may be adjusted. For example, increasing the rolling speed increases the amount of rolling oil caught between the metal sheet 64 and the rolling rolls 66a and 66b. This suppresses the formation of oil pits on the surface of the metal sheet 64. In this way, by adjusting the conveying speed of the metal sheet 64, the density of oil pits on the surface of the metal sheet 64 can be controlled. The rolling speed may be 50 m / min or more, 70 m / min or more, or 100 m / min or more. Preferably, the rolling speed is 200 m / min or less. The rolling speed may be 150 m / min or less, 100 m / min or less, or 80 m / min or less.

[0068] The rolling speed may be determined by any combination of one of several candidate upper limits and any one of several candidate lower limits. For example, the rolling speed may be 30 m / min or more and 200 m / min or less, or 50 m / min or more and 150 m / min or less. The range of the rolling speed may also be determined by any combination of two of several candidate upper limits. For example, the rolling speed may be 150 m / min or more and 200 m / min or less, or 100 m / min or more and 150 m / min or less. The range of the rolling speed may also be determined by any combination of two of several candidate lower limits. For example, the range of the rolling speed may be 30 m / min or more and 50 m / min or less, or 50 m / min or more and 70 m / min or less. The rolling speed is preferably 30 m / min or more and 200 m / min or less, more preferably 30 m / min or more and 150 m / min or less, more preferably 30 m / min or more and 100 m / min or less, and more preferably 30 m / min or more and 80 m / min or less.

[0069] The diameter of the rolling roll may also be adjusted. For example, increasing the diameter of the rolling roll increases the number of oil pits formed on the surface of the metal sheet 64. In this way, by adjusting the diameter of the rolling roll, it is possible to control the density of oil pits on the surface of the metal sheet 64. The diameter of the rolling roll is preferably 28 mm or more. The diameter of the rolling roll may be 40 mm or more, or may be 50 mm or more. The diameter of the rolling roll is preferably 150 mm or less. The diameter of the rolling roll may be 120 mm or less, 100 mm, or 80 mm or less.

[0070] The range of the diameter of the mill roll may be determined by a combination of any one of a plurality of upper limit candidate values ​​and any one of a plurality of lower limit candidate values. For example, the diameter of the mill roll may be 28 mm or more and 150 mm or less, or 40 mm or more and 120 mm or less. The range of the diameter of the mill roll may also be determined by a combination of any two of a plurality of upper limit candidate values. For example, the diameter of the mill roll may be 120 mm or more and 150 mm or less. The range of the diameter of the mill roll may also be determined by a combination of any two of a plurality of lower limit candidate values. For example, the diameter of the mill roll may be 28 mm or more and 40 mm or less. The diameter of the mill roll is preferably 28 mm or more and 150 mm or less, more preferably 40 mm or more and 120 mm or less, more preferably 50 mm or more and 100 mm or less, and more preferably 50 mm or more and 80 mm or less.

[0071] In the rolling process, the pressure of the rolling actuator may be adjusted to adjust the shape of the metal sheet 64. In addition to the rolling rolls (work rolls) 66a, 66b, the shape of the backup rolls may be adjusted as appropriate, and the position of the backup rolls may be adjusted as appropriate in the sheet width direction.

[0072] In the cold rolling process, a coolant such as kerosene or neat oil may be supplied between the base material 60 and the rolling rolls 66a, 66b, thereby controlling the temperature of the base material.

[0073] Furthermore, by appropriately selecting the coolant, the number and area of ​​oil pits and rolling lines formed on the surface of the metal sheet 64 can be adjusted. For example, neat oil can be used as the coolant. Neat oil has the characteristic of not causing a significant increase in viscosity during rolling. Therefore, by using neat oil as the coolant, the amount of coolant caught between the metal sheet 64 and the rolling rolls 66a and 66b can be reduced. This suppresses the formation of oil pits on the surface of the metal sheet 64.

[0074] Furthermore, by appropriately selecting the surface roughness of the rolling rolls, the number and area of ​​oil pits and rolling lines formed on the surface of the metal sheet 64 can be adjusted. For example, by reducing the surface roughness Ra of the rolling rolls, the formation of rolling lines on the surface of the metal sheet 64 can be suppressed. The surface roughness Ra of the rolling rolls is preferably 0.2 μm or less. The surface roughness Ra of the rolling rolls may be 0.15 μm or less, 0.1 μm or less, or 0.05 μm or less. The surface roughness Rz of the rolling rolls is preferably 2.0 μm or less. The surface roughness Rx of the rolling rolls may be 1.5 μm or less, 1.0 μm or less, or 0.5 μm or less. Also, the surface roughness Rz of the rolling rolls is preferably 2.0 μm or less. The surface roughness Rz of the rolling rolls may be 1.5 μm or less, 1.0 μm or less, or 0.5 μm or less. The surface roughness Ra and Rz are measured based on JIS B 0601:2013.

[0075] Furthermore, an analysis process may be carried out before, during, or after the rolling process to analyze the quality and properties of the base material 60 or metal sheet 64. For example, the composition may be analyzed by irradiating the base material 60 or metal sheet 64 with fluorescent X-rays. Alternatively, the amount of thermal expansion of the base material 60 or metal sheet 64 may be measured by thermomechanical analysis (TMA).

[0076] (Annealing process) Thereafter, in order to remove residual stress accumulated in the metal sheet 64 due to rolling, an annealing process may be performed using an annealing device 67, as shown in FIG. 7. The annealing process may be performed while pulling the metal sheet 64 in the conveying direction (longitudinal direction), as shown in FIG. 7. That is, the annealing process may be performed as continuous annealing while conveying, rather than so-called batch annealing. In this case, it is preferable to set the temperature and conveying speed so as to prevent deformation such as buckling of the metal sheet 64. By performing the annealing process, it is possible to obtain a metal sheet 64 from which residual strain has been removed to a certain extent. Note that FIG. 7 shows an example in which the metal sheet 64 is conveyed horizontally during the annealing process, but this is not limited thereto, and the metal sheet 64 may be conveyed in other directions, such as vertically, during the annealing process.

[0077] The conditions for the annealing step are appropriately set depending on the thickness and reduction rate of the metal plate 64, but for example, the annealing step is performed at a temperature in the range of 500°C to 600°C for 30 to 90 seconds. Note that the number of seconds above represents the time required for the metal plate 64 to pass through a space adjusted to a predetermined temperature in the annealing device 67. The temperature for the annealing step may be set so as not to soften the metal plate 64.

[0078] The lower limit of the annealing process temperature may be lower than the 500°C mentioned above. For example, the annealing process temperature may be 400°C or higher, or 450°C or higher. The upper limit of the annealing process temperature may be higher than the 600°C mentioned above. For example, the annealing process temperature may be 700°C or lower, or 650°C or lower. The range of the annealing process temperature may also be determined by any combination of one of the above-mentioned candidate upper limit values ​​and any one of the above-mentioned candidate lower limit values. For example, the annealing process temperature may be 400°C or higher and 700°C or lower, or 450°C or higher and 650°C or lower. The range of the annealing process temperature may also be determined by any combination of two of the above-mentioned candidate upper limit values. For example, the annealing process temperature may be 650°C or higher and 700°C or lower. The range of the annealing process temperature may also be determined by any combination of two of the above-mentioned candidate lower limit values. For example, the annealing process temperature may be 400°C or higher and 450°C or lower.

[0079] The duration of the annealing process may be 40 seconds or more, or 50 seconds or more. The lower limit of the annealing process duration may be shorter than the 30 seconds mentioned above. For example, the duration of the annealing process may be 10 seconds or more, or 20 seconds or more. The duration of the annealing process may also be 80 seconds or less, 70 seconds or less, or 60 seconds or less. The upper limit of the annealing process duration may also be longer than the 90 seconds mentioned above. For example, the duration of the annealing process may be 100 seconds or less. The range of the annealing process duration may also be determined by any combination of one of the above-mentioned candidate upper limit values ​​and any one of the above-mentioned candidate lower limit values. For example, the duration of the annealing process may be 10 seconds or more and 100 seconds or less, 20 seconds or more and 90 seconds or less, 30 seconds or more and 80 seconds or less, 40 seconds or more and 70 seconds or less, or 50 seconds or more and 60 seconds or less. The range of the annealing process duration may also be determined by any combination of two of the above-mentioned candidate upper limit values. For example, the annealing time may be 90 seconds or more and 100 seconds or less. The range of the annealing time may also be determined by a combination of any two of the above-mentioned multiple lower limit candidate values. For example, the annealing time may be 10 seconds or more and 20 seconds or less.

[0080] The time for the annealing step may be determined depending on the temperature for the annealing step. For example, if the temperature for the annealing step is high, the growth of the crystal grains proceeds quickly, and if the time for the annealing step is too long, the average cross-sectional area of ​​the crystal grains will be 50 μm , as described later. 2 In consideration of this, the upper limit of the annealing time may be determined depending on the temperature of the annealing process so that the average cross-sectional area of ​​the crystal grains does not exceed the second threshold. Examples of the upper limit of the annealing time determined depending on the temperature of the annealing process are shown below. ·Over 350℃ and below 400℃: 12 hours or less ·Over 400℃ and below 450℃: 30 minutes or less ·Over 450℃ and below 500℃: 10 minutes or less ·Over 500℃ and below 550℃: 5 minutes or less ·Over 550℃ and below 600℃: 3 minutes or less ·Over 600℃ and below 650℃: 1 minute or less

[0081] Preferably, the annealing step is performed in a non-reducing atmosphere or an inert gas atmosphere. Here, a non-reducing atmosphere refers to an atmosphere that does not contain a reducing gas such as hydrogen. "Does not contain a reducing gas" means that the concentration of a reducing gas such as hydrogen is 10% or less. In the annealing step, the concentration of the reducing gas may be 8% or less, 6% or less, 4% or less, 2% or less, or 1% or less. Furthermore, an inert gas atmosphere refers to an atmosphere in which the concentration of an inert gas such as argon gas, helium gas, or nitrogen gas is 90% or more. In the annealing step, the concentration of the inert gas may be 92% or more, 94% or more, 96% or more, 98% or more, or 99% or more. Performing the annealing step in a non-reducing atmosphere or an inert gas atmosphere can prevent nickel compounds such as nickel hydroxide from being formed on the surface layer of the metal plate 64. The annealing device 67 may have a mechanism for monitoring the inert gas concentration or a mechanism for adjusting the inert gas concentration.

[0082] Before the annealing step, a cleaning step may be performed to clean the metal plate 64. This makes it possible to prevent foreign matter from adhering to the surface of the metal plate 64 during the annealing step. As a cleaning liquid for cleaning, for example, a hydrocarbon-based liquid can be used.

[0083] Furthermore, while Figure 7 shows an example in which the annealing process is carried out while the metal sheet 64 is pulled in the longitudinal direction, the process is not limited to this, and the annealing process may also be carried out with the metal sheet 64 wound on the core 61. In other words, batch-type annealing may be performed. However, when the annealing process is carried out with the metal sheet 64 wound on the core 61, the metal sheet 64 may develop a warp corresponding to the winding diameter of the winding body 62. Therefore, depending on the winding diameter of the winding body 62 and the material constituting the base material 60, it may be advantageous to carry out the annealing process while the metal sheet 64 is pulled in the longitudinal direction.

[0084] Subsequently, a slitting process may be performed to cut off both ends of the metal sheet 64 obtained by the rolling process in the width direction, within a predetermined range, so that the width of the metal sheet 64 is within a predetermined range. This slitting process is performed to remove cracks that may occur at both ends of the metal sheet 64 due to rolling. By performing such a slitting process, it is possible to prevent the phenomenon of the metal sheet 64 breaking, so-called sheet breakage, from occurring starting from cracks.

[0085] The width of the portion cut off in the slitting step may be adjusted so that the shape of the metal plate 64 after the slitting step is symmetrical in the width direction. The slitting step may also be performed before the above-mentioned annealing step.

[0086] Note that the long metal plate 64 having a predetermined thickness may be manufactured by repeating at least two of the above-described rolling, annealing, and slitting steps multiple times.

[0087] After the annealing step, a crystal grain inspection step is carried out to inspect the dimensions of crystal grains appearing in the cross section of the metal plate 64. Specifically, it is inspected whether the average cross-sectional area of ​​the crystal grains is equal to or larger than a first threshold value and equal to or smaller than a second threshold value. The background to carrying out such an inspection will be explained below.

[0088] As a result of extensive research, the present inventors have found that as the thickness of the metal plate 64 decreases, specific deformed portions are more likely to be formed in the metal plate 64 or in the deposition mask 20 manufactured from the metal plate 64. The deformed portions are, for example, localized protrusions or depressions. The deformed portions are generated, for example, when the metal plate 64 is transported in the manufacturing process of the deposition mask 20 or when the deposition mask 20 manufactured from the metal plate 64 is handled. The smaller the thickness of the metal plate 64, the more likely the deformed portions are to be generated. For example, the deformed portions are more likely to be generated when the thickness of the metal plate 64 is 30 μm or less, even more likely to be generated when the thickness of the metal plate 64 is 25 μm or less, and even more likely to be generated when the thickness of the metal plate 64 is 20 μm or less.

[0089] A possible reason why deformation occurs more easily when the thickness of the metal plate 64 is small is a decrease in the strength of the metal plate 64. On the other hand, a possible method for ensuring the strength of the metal plate 64 even when the thickness of the metal plate 64 is small is to reduce the size of the crystal grains of the metal plate 64.

[0090] Possible indicators of the size of crystal grains include the grain size, cross-sectional area, and volume of the crystal grains. The present inventors have conducted extensive research and found that a method for quantitatively determining the size of crystal grains in a metal plate 64 having a thickness of 30 μm or less, in which the average cross-sectional area of ​​the crystal grains is calculated based on electron backscatter diffraction (hereinafter also referred to as EBSD (Electron Backscatter Diffraction Patterns) method), is superior in terms of accuracy. Therefore, in this embodiment, it is proposed to inspect whether the average cross-sectional area of ​​the crystal grains in the metal plate 64 is equal to or less than a second threshold value. The second threshold value is determined depending on the strength required for the metal plate 64, and may be, for example, 50 μm. 2 The second threshold is 45 μm 2 may be 40 μm 2 may be 35 μm 2 may be 30 μm 2 may be 25 μm 2 may be 20 μm 2This may also be the case. If the thickness of the metal plate 64 is smaller, a smaller second threshold may be adopted. For example, if the thickness of the metal plate 64 is 20 μm or less, for example less than 20 μm or 15 μm or less, the second threshold may be, for example, 20 μm. 2 And, 15 μm 2 It may also be 10 μm 2 This is also acceptable. Details of the measurement method using the EBSD method will be described later.

[0091] On the other hand, the inventors of this invention conducted diligent research and found that if the size of the crystal grains of the metal plate 64 becomes too small, the weldability of the metal plate 64 decreases. For example, they found that when welding a deposition mask 20 made from the metal plate 64 to the frame 15, cracks tend to occur on the surface of the metal plate 64. Taking this into consideration, in this embodiment, we propose checking whether the average cross-sectional area of ​​the crystal grains of the metal plate 64 is greater than or equal to a first threshold. The first threshold is determined according to the required weldability of the metal plate 64, for example, 0.5 μm 2 The first threshold is 2 μm. 2 may be 5 μm 2 may be 10 μm 2 It may also be 15 μm 2 may be 20 μm 2 may be.

[0092] While there are various types of average cross-sectional areas, such as area-average cross-sectional area and number-average cross-sectional area (discussed later), the area-average cross-sectional area is the one for which the preferred range is determined by the first and second thresholds mentioned above. In the following explanation, unless otherwise specified, "average cross-sectional area" refers to "area-average cross-sectional area." When the number-mean cross-sectional area is used as the average cross-sectional area, in a metal plate 64 having a thickness of 30 μm or less, the second threshold is, for example, 3.2 μm. 2 and 3.0 μm 2 may be 2.5 μm 2 may be 2.0 μm 2 may be 1.8 μm 2 may be 1.6 μm 2It may also be 1.4 μm 2 When the thickness of the metal plate 64 is 20 μm or less, for example, less than 20 μm or 15 μm or less, the second threshold value may be, for example, 1.6 μm. 2 And, 1.4 μm 2 It may also be 1.2 μm 2 Even if it is 1.0 μm 2 The first threshold may be, for example, 0.2 μm. 2 And, 0.4 μm 2 It may also be 0.6 μm 2 It may also be 0.8 μm 2 It may also be 1.0 μm 2 It may also be 1.2 μm 2 may be.

[0093] In the inspection process, for example, the average cross-sectional area of ​​the crystal grains is 0.5 μm 2 More than 50μm 2 The metal plate 64 having an average cross-sectional area of ​​the crystal grains of 0.5 μm or less is judged to be acceptable. 2 Less than or equal to 50 μm 2 The metal plate 64 exceeding this value is judged as unacceptable.

[0094] The range of the average cross-sectional area of ​​the crystal grains of the metal plate 64 that is judged to pass the inspection process may be determined by any one of the above-mentioned candidates for the second threshold that defines the upper limit and any one of the above-mentioned candidates for the first threshold that defines the lower limit. For example, the average cross-sectional area of ​​the crystal grains of the metal plate 64 that is judged to pass, i.e., the selected metal plate 64, is 2 μm 2 45μm or more 2 The following may also be acceptable: 5 μm 2 More than 40μm 2 The following may also be acceptable, 10 μm 2 More than 35μm 2 The following may also be used, 15 μm 2 More than 30μm 2 May be less than 20 μm 2 More than 25μm 2The following is also possible. Furthermore, the range of the average cross-sectional area of ​​the crystal grains of the selected metal plate 64 may be determined by any two combinations of the above-mentioned multiple candidate second thresholds that define the upper limit. For example, the average cross-sectional area of ​​the crystal grains of the selected metal plate 64 is 45 μm 2 More than 50μm 2 The following is also possible. Furthermore, the range of the average cross-sectional area of ​​the crystal grains of the selected metal plate 64 may be determined by any two combinations of the above-mentioned multiple candidate first thresholds that define the lower limit. For example, the average cross-sectional area of ​​the crystal grains of the selected metal plate 64 is 0.5 μm². 2 More than 2μm 2 It may be the following:

[0095] The EBSD measurement method will be described below with reference to Figures 8 to 10. The EBSD method is a method of analyzing crystal grains based on the diffraction pattern of an electron beam (hereinafter also called the EBSD pattern) obtained when an electron beam is irradiated onto the sample surface from a direction that is significantly inclined with respect to the sample surface using a scanning electron microscope (hereinafter also called SEM). As a measurement device, for example, a combination of a Schottky field emission scanning electron microscope and an EBSD detector can be used. As an EBSD detector, for example, an OIM (Orientation Imaging Microscopy) detector manufactured by TSL Solutions Co., Ltd. can be used.

[0096] In the measurement using the EBSD method, first, a metal plate 64 is cut in a direction perpendicular to the conveying direction D1 (hereinafter also referred to as the rolling direction) of the metal plate 64 during the rolling process to prepare a test piece 50. The rolling direction D1 is the direction in which linear rolling marks extend that are confirmed when the shiny surface of the metal plate 64 is observed with a metallurgical microscope. A trimming razor, for example, can be used as a cutting tool. The thickness of the test piece 50 is equal to the thickness of the metal plate 64. Next, the test piece 50 is sealed with resin. For example, an epoxy resin is used as the resin. The thickness of the resin is, for example, 1 mm. Next, the test piece is cut together with the resin using a trimming razor along a direction perpendicular to the rolling direction D1 and perpendicular to the surface direction of the test piece. This exposes the cross section 50c of the test piece of the metal plate 64 from the resin. 8, a sample 56 can be obtained, which includes a test piece 50 in which a cross section 50c for measurement is exposed from the resin 55. The sample 56 is configured so that the cross section 50c forms an angle of −10° or more and +10° or less with respect to a plane perpendicular to the rolling direction D1 of the metal plate 64.

[0097] After exposing the cross section 50c for measurement from the resin 55, the cross section 50c of the test piece 50 may be trimmed using a microtome. In this trimming, for example, in order to reduce mechanical distortion of the cross section 50c of the test piece 50, the microtome is used to cut the resin 55 sealing the test piece 50 together with the test piece 50 in a direction perpendicular to the cross section 50c of the test piece 50 by approximately 1 mm. Next, using an ion milling device, a broad argon ion beam is irradiated in a direction perpendicular to the cross section 50c of the test piece 50. Specifically, a shielding plate is placed on the test piece 50, and with the test piece 50 slightly protruding from the shielding plate, accelerated argon ions are irradiated onto the test piece 50 from the shielding plate side to process the test piece 50 and generate the cross section 50c to be observed. In this case, a cross section 50c having a plane direction parallel to the irradiation direction of the argon ions is obtained. These operations are performed to precisely expose the cross section 50c of the test piece 50 so as to minimize mechanical damage to the crystal structure that occurred in the previous process. Note that the "perpendicular direction" does not have to be a direction that forms a 90-degree angle with respect to the target surface or direction, and may include an error of about 10 degrees. For example, a direction perpendicular to the rolling direction D1 is a direction that forms an angle of 80 degrees or more and 100 degrees or less with respect to the rolling direction D1. Furthermore, a direction perpendicular to the surface is a direction that forms an angle of 80 degrees or more and 100 degrees or less with respect to the surface.

[0098] Next, an electron beam E is irradiated from an objective lens 57 of the Schottky field emission scanning electron microscope onto a cross section 50c of the test piece 50 of the sample 56. An EBSD pattern generated from the test piece 50 is detected using an EBSD detector 58.

[0099] An example of the conditions for a scanning electron microscope used in EBSD is as follows: • Magnification: 2000x (The standard magnification used for photography is Polaroid 545) • Acceleration voltage: 15kV • Working distance: 15mm • Sample tilt angle: 70 degrees

[0100] FIG. 9 shows an example of a process for adjusting the tilt angle of a sample 56 including a test piece 50. First, the sample 56 including the test piece 50 is fixed to a sample stage with the surface of the sample 56 on which the test piece 50 is exposed (the observation surface or measurement surface) facing upward, and the sample 56 is inserted into a scanning electron microscope and moved to a position directly below the objective lens 57. Next, the sample 56 is rotated by an angle φ1 toward the EBSD detector 58, centered on the intersection of the electron beam E irradiated from the objective lens 57 and the normal N1 of the EBSD detector 58. The angle φ1 corresponds to the above-mentioned sample tilt angle, which is, for example, 70 degrees. In this case, the angle φ2 formed by the electron beam E incident on the sample 56 from the objective lens 57 with respect to the surface of the sample 56 is 20 degrees.

[0101] Next, the measurement results obtained by the EBSD method, i.e., the EBSD pattern, are analyzed to calculate the average cross-sectional area of ​​the crystal grains 51 appearing in the cross-section 50c of the test specimen 50. An example of the conditions for crystal analysis by the EBSD method is as follows. Step size: 70nm Analysis conditions: The following analysis is performed using the crystal orientation analysis software OIM (Ver. 7.3) manufactured by TSL Solutions Co., Ltd.

[0102] When the average cross-sectional area of ​​the crystal grains is large, the observation magnification with the SEM is set to the first magnification. For example, when the average cross-sectional area of ​​the crystal grains is 2 μm 2 In the above cases, the observation magnification using the SEM is set to a first magnification. The first magnification is, for example, 2000x. Furthermore, if the number of crystal grains appearing in the measurement area to be analyzed is less than 1000, images may be acquired at multiple positions on the cross section of the metal plate 64 while shifting the measurement area, and the acquired images may be joined to generate an image showing 1000 or more crystal grains. In this case, the measurement area is set to the center to both ends in the thickness direction of the test piece 50 of the metal plate 64, and portions of the cross section 50c where resin is attached and portions where an acid-resistant coating is present are excluded from the measurement area.

[0103] If the average cross-sectional area of ​​the crystal grains is small, the observation magnification in the SEM should be set to a second magnification, which is higher than the first magnification. For example, if the average cross-sectional area of ​​the crystal grains is 2 μm 2 If the number of crystal grains is less than 1000, the observation magnification with the SEM is set to the second magnification. The second magnification is, for example, 5000 times. In this case, if necessary, multiple images obtained may be joined to generate an image in which 1000 or more crystal grains appear.

[0104] The analysis is performed by excluding data whose Confidence Index (CI value) is below a certain value, as defined by OIM (Version 7.3), a crystal orientation analysis software from TSL Solutions, Inc. For example, data with a CI value of 0.15 or less is excluded. This makes it possible to eliminate the influence of the resin used in pre-processing on the front and back of sample 56, the grain boundaries present in the cross section of sample 56, and amorphous materials.

[0105] According to this embodiment, by employing the EBSD method, it is possible to obtain information with high accuracy regarding the dimensions of the crystal grains of the metal plate 64. Therefore, the inspection process of the metal plate 64 can be carried out with high accuracy.

[0106] Figure 27 shows the grain size distribution of the crystalline structure with an average cross-sectional area of ​​0.5 μm 2 More than 50μm 2 27 is a diagram showing an example of the distribution of the average cross-sectional area of ​​crystal grains of a plurality of metal plates 64 selected based on the criteria for determining that metal plates that satisfy the following criteria are acceptable. In FIG. 27, the horizontal axis represents the value of the average cross-sectional area of ​​crystal grains calculated for each metal plate 64. The vertical axis represents the number of metal plates 64 having an average cross-sectional area of ​​crystal grains within the range shown on the horizontal axis. For example, among the plurality of selected metal plates 64, 2 More than 30μm 2 The number of metal plates 64 having an average cross-sectional area of ​​crystal grains less than 0.5 μm is 15. As shown in FIG. 27, due to measurement errors, etc., some of the selected metal plates 64 may have an average cross-sectional area of ​​less than 0.5 μm. 2 Less than or 50 μm 2 In some cases, the average cross-sectional area of ​​the crystal grains may exceed a certain value.

[0107] Figure 28 shows that the average cross-sectional area of ​​the crystal grains is 10 μm². 2 More than 40μm 2 This figure shows an example of the distribution of the average cross-sectional area of ​​crystal grains of multiple metal plates 64 selected based on the following criteria for determining whether a metal plate is acceptable. The meaning of the horizontal and vertical axes in Figure 28 is the same as in Figure 27. In the example of Figure 28, the range of metal plates 64 that are determined to be acceptable and selected is narrower compared to the example of Figure 27. In this case, performing the selection shown in Figure 28 is equivalent to performing the selection shown in Figure 27.

[0108] In the above description, an example was shown in which an inspection step, which inspects the metal plate 64 based on the average cross-sectional area of ​​the crystal grains, is performed to determine whether the metal plate 64 is acceptable or not, that is, for the sorting of the metal plate 64. In other words, an example was shown in which the inspection step functions as a sorting step for sorting the metal plate 64 in the manufacturing method of the metal plate 64. However, the inspection step may be used for purposes other than sorting the metal plate 64 in the manufacturing method of the metal plate 64.

[0109] The sorting conditions in the sorting process are arbitrary. For example, the sorting process may select metal plates 64 having an average cross-sectional area of ​​crystal grains that falls within a range determined by any one of the above-mentioned candidates for the upper limit of the second threshold and any one of the above-mentioned candidates for the lower limit of the first threshold. Alternatively, the sorting process may select metal plates 64 having an average cross-sectional area of ​​crystal grains that falls within a range determined by any two of the above-mentioned candidates for the upper limit of the second threshold. Alternatively, the sorting process may select metal plates 64 having an average cross-sectional area of ​​crystal grains that falls within a range determined by any two of the above-mentioned candidates for the lower limit of the first threshold.

[0110] An example will be described in which the inspection process is used for purposes other than sorting metal plates 64 in the manufacturing method of metal plates 64. For example, inspection of metal plates 64 based on the average cross-sectional area of ​​crystal grains may be used to optimize the conditions for manufacturing the metal plates 64, such as the conditions for the rolling process and the conditions for the annealing process. Specifically, first, metal plates 64 are manufactured under various rolling conditions and annealing conditions, and the average cross-sectional area of ​​the crystal grains of the obtained metal plates 64 is calculated. Then, the rolling conditions and annealing conditions are compared with the average cross-sectional area of ​​the crystal grains of the obtained metal plates 64. As a result, when the average cross-sectional area of ​​the crystal grains is 0.5 μm 2 More than 50μm 2 It is possible to find rolling conditions, annealing conditions, and the like for manufacturing a metal plate 64 that is equal to or less than the above with a high probability. In this way, inspection of the metal plate 64 based on the average cross-sectional area of ​​the crystal grains may be used to find appropriate rolling conditions and annealing conditions. In this case, it is not necessary to perform the inspection process of calculating the average cross-sectional area of ​​the crystal grains on all of the metal plates 64 obtained in the actual manufacturing process. For example, the inspection process may be performed on only some of the metal plates 64. Alternatively, once manufacturing conditions such as the rolling conditions and annealing conditions have been set, the inspection process of calculating the average cross-sectional area of ​​the crystal grains may not be performed at all.

[0111] Figure 29 shows the average cross-sectional area of ​​the crystal grains is 0.5 μm 2 More than 50μm 2 This figure shows an example of the distribution of the average cross-sectional area of ​​crystal grains in a plurality of metal plates 64 manufactured under manufacturing conditions found using a judgment condition that a metal plate 64 that satisfies the following criteria is accepted. The horizontal and vertical axes shown in FIG. 29 have the same meanings as those in FIG. 27. In the example of FIG. 29, even if a sorting step is not performed, the plurality of manufactured metal plates 64 have a grain size of 0.5 μm or less. 2 More than 50μm 2 The following average cross-sectional areas of the crystal grains are present.

[0112] Furthermore, after the rolling step or the annealing step, a visual inspection step may be performed to inspect the appearance of the metal plate 64. The visual inspection step may include a step of inspecting the appearance of the metal plate 64 using an automatic inspection machine. The visual inspection step may also include a step of visually inspecting the appearance of the metal plate 64.

[0113] Furthermore, after the rolling process or the annealing process, a shape inspection process may be performed to inspect the shape of the metal plate 64. For example, a three-dimensional measuring device may be used to measure the position of the surface of the metal plate 64 in the thickness direction within a predetermined region of the metal plate 64.

[0114] According to the method for manufacturing a metal plate according to this embodiment, it is possible to obtain a metal plate 64 having an average cross-sectional area of ​​crystal grains that satisfies the above-mentioned criteria. 2 More than 50μm 2 A metal plate 64 can be obtained as follows.

[0115] In the above embodiment, an example has been shown in which both the first threshold value defining the lower limit of the average cross-sectional area of ​​the crystal grains and the second threshold value defining the upper limit of the average cross-sectional area of ​​the crystal grains are used in determining whether the metal plate 64 is acceptable or not and in sorting the metal plate 64 in the inspection process. However, this is not limited to this, and only either the first threshold value or the second threshold value may be used in determining whether the metal plate 64 is acceptable or not and in sorting the metal plate 64 in the inspection process. For example, the metal plate 64 having an average cross-sectional area of ​​the crystal grains equal to or greater than a first threshold may be judged as acceptable or selected. When the average cross-sectional area of ​​the crystal grains of the metal plate 64 is equal to or greater than the first threshold, the metal plate 64 can be made weldable. Alternatively, the metal plate 64 having the average cross-sectional area of ​​the crystal grains equal to or less than the second threshold may be judged as acceptable or selected. By having the average cross-sectional area of ​​the crystal grains of the metal plate 64 equal to or less than the second threshold, the metal plate 64 can be made strong.

[0116] In the above embodiment, rolling is used as a method for reducing the thickness of the metal plate 64, but the present invention is not limited to this. For example, the thickness of the metal plate 64 may be reduced by etching the metal plate 64 from the first surface 64a side, the second surface 64b side, or both the first surface 64a side and the second surface 64b side. Such etching may be performed instead of or in addition to the rolling process.

[0117] Even when the thickness of the metal plate 64 is reduced by etching, the metal plate 64 can be welded because the average cross-sectional area of ​​the crystal grains of the metal plate 64 after etching is equal to or greater than the first threshold. Furthermore, the metal plate 64 can be strengthened because the average cross-sectional area of ​​the crystal grains of the metal plate 64 after etching is equal to or less than the second threshold. Note that the cross-sectional area of ​​the crystal grains of the metal plate 64 does not change due to etching.

[0118] Next, using a metal plate 64 in which the average cross-sectional area of ​​the crystal grains is equal to or greater than the first threshold and equal to or less than the second threshold, 2 More than 50μm 2 A method for manufacturing a deposition mask 20 using a metal plate 64 will be described below mainly with reference to FIGS. 11 to 15. Here, a method for manufacturing a deposition mask 20 by etching a metal plate 64 to form through-holes 25 in the metal plate 64 will be described. FIG. 11 is a diagram showing a manufacturing apparatus 59 for manufacturing a deposition mask 20 using a metal plate 64. First, a wound body 62 in which the metal plate 64 is wound around a core 61 is prepared. Then, the core 61 is rotated to unwind the wound body 62, thereby supplying a band-like metal plate 64 as shown in FIG.

[0119] The supplied metal plate 64 is transported by transport rollers 72 to a processing device 70 and a separating device 73 in this order. The processing device 70 performs a processing step of processing the metal plate 64 to form through holes 25 in the metal plate 64. In the present embodiment, a large number of through holes 25 corresponding to a plurality of deposition masks 20 are formed in the metal plate 64. In other words, a plurality of deposition masks 20 are allocated to the metal plate 64. The separating device 73 performs a separating step of separating from the metal plate 64 a portion of the metal plate 64 in which a plurality of through holes 25 corresponding to one deposition mask 20 are formed. In this manner, a sheet-like deposition mask 20 can be obtained.

[0120] The processing steps will be described with reference to FIGS. 12 to 15. First, a resist film containing a photosensitive resist material is formed on the first surface 64a and the second surface 64b of the metal plate 64. For example, a coating liquid containing a photosensitive resist material such as casein is applied to the metal plate 64, and then the coating liquid is dried to form the resist film. Alternatively, the resist film may be formed by attaching a dry film to the metal plate 64. Next, the resist film is exposed to light and developed. As a result, a first resist pattern 65a can be formed on the first surface 64a of the metal plate 64, and a second resist pattern 65b can be formed on the second surface 64b of the metal plate 64, as shown in FIG. 12.

[0121] Next, as shown in FIG. 13 , a first-surface etching process is performed in which regions of the first surface 64a of the metal plate 64 that are not covered by the first resist pattern 65a are etched using a first etching solution. For example, the first etching solution is sprayed toward the first surface 64a of the metal plate 64 through the first resist pattern 65a from a nozzle disposed on the side facing the first surface 64a of the transported metal plate 64. As a result, as shown in FIG. 13 , the first etching solution erodes the regions of the metal plate 64 that are not covered by the first resist pattern 65a. This forms a large number of first recesses 30 on the first surface 64a of the metal plate 64. For example, a first etching solution containing a ferric chloride solution and hydrochloric acid is used.

[0122] Next, as shown in Figure 14, a second surface etching process is performed to etch the area of ​​the second surface 64b of the metal plate 64 that is not covered by the second resist pattern 65b, thereby forming a second recess 35 on the second surface 64b. The second surface etching process is carried out until the first recess 30 and the second recess 35 are connected to each other, thereby forming a through hole 25. As the second etching solution, a solution containing, for example, ferric chloride solution and hydrochloric acid is used, similar to the first etching solution described above. During the second surface etching process, the first recess 30 may be covered with a resin 69 that is resistant to the second etching solution, as shown in Figure 14.

[0123] Subsequently, as shown in Figure 15, the resin 69 is removed from the metal plate 64. The resin 69 can be removed, for example, by using an alkaline stripping solution. When an alkaline stripping solution is used, the resist patterns 65a and 65b are removed at the same time as the resin 69, as shown in Figure 15. After removing the resin 69, the resist patterns 65a and 65b may be removed separately from the resin 69 using a different stripping solution than the one used to remove the resin 69.

[0124] Thereafter, the deposition masks 20 allocated to the metal plate 64 are taken out one by one. For example, a portion of the metal plate 64 in which a plurality of through holes 25 corresponding to one deposition mask 20 are formed is separated from the rest of the metal plate 64. In this way, the deposition masks 20 can be obtained.

[0125] The method for forming the through holes 25 in the metal plate 64 is not limited to etching. For example, the through holes 25 may be formed in the metal plate 64 by laser processing, in which a laser is irradiated onto the metal plate 64. Even in this case, the average cross-sectional area of ​​the crystal grains is 0.5 μm 2 More than 50μm 2 By setting the thickness to 30 μm or less, the metal plate can have strength and weldability, which can prevent local deformations such as dents from being formed in the metal plate during the manufacturing process of the deposition mask 20 or handling of the deposition mask 20.

[0126] Next, a vapor deposition mask inspection step may be performed to inspect the vapor deposition mask 20. In the vapor deposition mask inspection step, for example, the surface of the metal plate 64 constituting the vapor deposition mask 20 is inspected to see if there are any deformed parts such as local protrusions or depressions. Figure 16 shows an example of a deformed part 28 that may be formed on the metal plate 64. In the example shown in Figure 16, the deformed part 28 is a local depression formed on the second surface 64b of the metal plate 64.

[0127] Figure 17 shows an example of the cross-sectional shape of the deformed portion 28 of the metal plate 64 shown in Figure 16. As shown in Figure 17, the deformed portion 28 formed as a local recess on the second surface 64b may appear as a local convex portion on the first surface 64a side. The dimension K1 of the deformed portion 28 in the planar direction of the metal plate 64 is, for example, 0.5 μm to several mm. Also, if the deformed portion 28 is a local recess, the depth K2 of the recess is, for example, 0.5 μm to 10 μm.

[0128] In the vapor deposition mask inspection process, for example, as shown in Figure 17, light L1 is irradiated onto the first surface 64a or the second surface 64b of the metal plate 64 constituting the vapor deposition mask 20, and it is visually confirmed whether or not there are deformed parts 28 on the metal plate 64. If there are no deformed parts 28 on the first surface 64a or the second surface 64b of the metal plate 64 of the vapor deposition mask 20, the vapor deposition mask 20 is deemed acceptable. If even one deformed part 28 is present, the vapor deposition mask 20 may be deemed unacceptable.

[0129] In this embodiment, as described above, the average cross-sectional area of ​​the crystal grains is 50 μm 2 The deposition mask 20 is manufactured using a metal plate 64 as described below. Therefore, even if the thickness of the metal plate 64 is 30 μm or less, the strength of the metal plate 64 can be ensured. Consequently, the formation of deformation portions 28 in the metal plate 64 during the manufacturing process of the deposition mask 20 can be suppressed. Therefore, the proportion of deposition masks 20 that are judged to be unacceptable in the deposition mask inspection process can be reduced.

[0130] Next, a fixing step was performed to fix the deposition mask 20 obtained as described above to the frame 15. This made it possible to obtain a deposition mask apparatus 10 comprising the deposition mask 20 and the frame 15.

[0131] In the fixing step, first, a stretching step was performed to adjust the position of the deposition mask 20 relative to the frame 15 while applying tension to the deposition mask 20. In the stretching step, first, as shown in FIG. 18, ears 17a and 17b of the deposition mask 20 are clamped and held by clamps 15a. In the example shown in FIG. 18, one ear 17a is held by two clamps 15a. The number and arrangement of the clamps 15a are arbitrary. Next, while applying tension to the deposition mask 20 via pullers 15b connected to the clamps 15a, the position and tension of the deposition mask 20 are adjusted so that the difference between the positions of all the through-holes 25 in the deposition mask 20 and the positions of the electrodes on the organic EL substrate 92 (or a substrate simulating the organic EL substrate 92) is equal to or less than a predetermined reference value. The reference value is, for example, 5 μm.

[0132] In the welding step, first, as shown in FIG. 19A , the ears 17 of the deposition mask 20 are placed on the frame 15 so that the second surface 20b faces the frame 15. Next, the ears 17 of the deposition mask 20 are heated to weld the ears 17 to the frame 15. As a method for heating the ears 17, for example, a method of irradiating the ears 17 with laser light L2 can be used. As the laser light L2, for example, a YAG laser light generated by a YAG laser device can be used. The spot diameter S of the laser light L2 is, for example, 0.1 mm or more and 0.3 mm or less.

[0133] As a YAG laser device, for example, one equipped with a crystal of YAG (yttrium aluminum garnet) doped with Nd (neodymium) can be used as the oscillation medium. In this case, a laser light with a wavelength of approximately 1064 nm is generated as the fundamental wave. Furthermore, by passing the fundamental wave through a nonlinear optical crystal, a second harmonic with a wavelength of approximately 532 nm is generated. Furthermore, by passing the fundamental wave and the second harmonic through a nonlinear optical crystal, a third harmonic with a wavelength of approximately 355 nm is generated. The third harmonic of the YAG laser light is readily absorbed by iron alloys containing nickel. Therefore, if the metal plate 64 constituting the lug portion 17 has an iron alloy containing nickel, it is preferable that the laser light L2 irradiated onto the lug portion 17 includes the third harmonic of the YAG laser light.

[0134] When the ear portion 17 is irradiated with laser light L2, a portion of the ear portion 17 and a portion of the frame 15 of the deposition mask 20 melt, forming a welded portion 19 that spans the ear portion 17 and the frame 15, as shown in Figure 19B.

[0135] Incidentally, in this embodiment, as described above, the crystal grains of the metal plate 64 are refined. Specifically, the average cross-sectional area of ​​the crystal grains of the metal plate 64 is 50 μm². 2 The following occurs. On the other hand, in the welded portion 19, which is heated and melted before solidifying, new crystal grains are generated by recrystallization. The dimensions of the newly generated crystal grains in the welded portion 19 are generally larger than the dimensions of the crystal grains that originally existed. For this reason, in the metal plate 64 after welding, the dimensions of the crystal grains in the welded portion 19 are likely to be larger than the dimensions of the crystal grains in the surrounding portion of the welded portion 19. If the difference in crystal grain dimensions is large, defects such as cracks are more likely to form in the metal plate 64. Figure 20 is a cross-sectional photograph showing the welded portion 19 formed when the ear portion 17 of a vapor deposition mask 20 made from a metal plate 64 is welded to a member 16. As the member 16, an Invar material with a greater thickness than the ear portion 17 was used. Figure 21 is an enlarged view of the welded portion 19 in Figure 20. In the examples shown in Figures 20 and 21, cracks 54 are formed at the boundary between the welded portion 19 and the surrounding portion of the ear portion 17, and on the surface of the member 16.

[0136] 20 and 21 is performed as follows. First, the ear 17 is welded to the member 16. Then, a portion including the weld 19 is cut out using metal scissors to prepare an object to be observed. Next, the object to be observed is processed using an ion milling device to generate a cross section of the object to be observed.

[0137] As the ion milling device, a cross-section polisher IB-09010CP manufactured by JEOL Ltd. can be used. An example of the processing conditions is as follows. Processing conditions: 6kV, 1.5 hours, protrusion width 100μm

[0138] In normal processing, the object to be observed is embedded in resin before being irradiated with argon ions. However, in this case, if the object to be observed was embedded in resin, it would have been difficult to adjust the position of the cross-section of the object to be observed to the center of the welded portion 19. Therefore, the object to be observed was irradiated with argon ions without embedding it in resin. As a result, as shown in Figure 21 and the area enclosed by the dotted line labeled W1 in Figure 23 (described later), there are streaky processing marks on the surface of the object to be observed on the side of the lug portion 17, caused by damage from argon ions. Also, as shown in Figure 21, the area enclosed by the dotted line labeled W2, a deposit layer of material removed by processing may form in the gap between the lug portion 17 and the member 16. The inventors of this application believe that these processing marks and deposit layers do not particularly adversely affect the observation of the crystalline state or the confirmation of the presence or absence of cracks in the welded portion 19 and its surrounding area.

[0139] Next, the cross section is observed using an SEM. For example, an ULTRA55 manufactured by Carl Zeiss can be used as the SEM. An example of the observation conditions for the SEM is as follows. Acceleration voltage: 5 kV Working distance: 4.5mm Detector: Inlens Aperture: 60μm High Current Magnification: 200x and 1000x (the standard magnification for photography is Polaroid 545)

[0140] 20 and 21 is considered to be caused by a large difference between the size of the crystal grains in the welded portion 19 and the size of the crystal grains in the surrounding area of ​​the welded portion 19. In this embodiment, as described above, the average cross-sectional area of ​​the crystal grains is 0.5 μm 2 The deposition mask 20 is manufactured using the metal plate 64 described above. This makes it possible to prevent the difference between the size of the crystal grains in the welded portion 19 and the size of the crystal grains in the surrounding area of ​​the welded portion 19 from becoming large. This makes it possible to prevent cracks from forming on the surface of the metal plate 64 after the welded portion 19 is formed. FIG. 22 is a cross-sectional photograph of the metal plate 64 and the frame 15 in which no cracks are formed. FIG. 23 is an enlarged view of the welded portion 19 in FIG. 22.

[0141] It should be noted that various modifications can be made to the above-described embodiment. Below, modifications will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described embodiment will be designated by the same reference numerals as those used for the corresponding parts in the above-described embodiment, and duplicated explanations will be omitted. Furthermore, if it is clear that the effects obtained in the above-described embodiment can also be obtained in the modified embodiment, the explanations thereof may be omitted.

[0142] In the above-described embodiment, an example has been shown in which the ear 17 is welded to the frame 15 by irradiating the ear 17 with the laser beam L2. However, the method of heating the ear 17 is not limited to irradiating the ear 17 with the laser beam L2. For example, the ear 17 may be heated by passing a current through the ear 17 and the frame 15.

[0143] In the above-described embodiment, an example has been shown in which the metal sheet 64 is obtained by rolling a base material. However, this is not limited thereto, and a metal sheet 64 having a desired thickness may also be produced by a foil-making process using a plating process. In the foil-making process, for example, a stainless steel drum partially immersed in a plating solution is rotated while a plating film is formed on the surface of the drum, and this plating film is then peeled off, thereby producing a long metal sheet in a roll-to-roll process. When producing a metal sheet made of an iron alloy containing nickel, a mixed solution of a solution containing a nickel compound and a solution containing an iron compound can be used as the plating solution. For example, a mixed solution of a solution containing nickel sulfamate and a solution containing iron sulfamate can be used. The plating solution may also contain additives such as malonic acid or saccharin.

[0144] The metal sheet obtained in this manner may then undergo the annealing process described above. Alternatively, before or after the annealing process, the slitting process described above may be performed to cut off both ends of the metal sheet in order to adjust its width to a desired width.

[0145] Even when a metal plate is manufactured using a plating process, similar to the embodiment described above, the average cross-sectional area of ​​the crystal grains appearing in a cross section that forms an angle of -10° to +10° with respect to a plane perpendicular to the longitudinal direction of the metal plate 64 (plating film) is 0.5 μm². 2 More than 50μm 2 The metal plate 64 is manufactured as follows: For example, the composition of the plating solution and conditions such as temperature and time in the foil manufacturing process are adjusted. The conditions of the annealing process may also be adjusted. The average cross-sectional area of ​​the crystal grains is 0.5 μm². 2 More than 50μm 2By doing the following, even when the thickness of the metal plate is 30 μm or less, the metal plate can be given strength and weldability, similar to the embodiment described above. This makes it possible to suppress the formation of localized deformations such as dents in the metal plate during the manufacturing process of the vapor deposition mask 20 and during handling of the vapor deposition mask 20. In addition, it is possible to suppress the formation of defects such as cracks in the vapor deposition mask 20 or the frame 15 when welding the vapor deposition mask 20 to the frame 15. The longitudinal direction of the plating film is the direction in which the elongated metal plate, formed by depositing a metal film on the surface of the drum by plating while the drum is rotating, extends.

[0146] In the above-described embodiment, an example was shown in which the vapor deposition mask 20 is manufactured by etching or laser processing a metal plate 64 to form through holes 25 in the metal plate 64. However, the invention is not limited to this, and the vapor deposition mask 20 may also be manufactured by forming a plating layer on a substrate in a predetermined pattern corresponding to the through holes 25, and then peeling the plating layer off the substrate. Such a method for manufacturing a vapor deposition mask 20 is disclosed, for example, in Japanese Patent Application Publication No. 2016-148112, so a detailed explanation is omitted here.

[0147] Even when the deposition mask 20 is manufactured by plating, the average cross-sectional area of ​​the crystal grains of the metal plate 64 made of the plating layer that constitutes the deposition mask 20 is 0.5 μm 2 More than 50μm 2 The deposition mask 20 is manufactured so as to satisfy the following conditions. For example, the composition of the plating solution and the conditions of the temperature and time in the plating process are adjusted. The conditions of the annealing process carried out after the plating process may also be adjusted. The average cross-sectional area of ​​the crystal grains is 0.5 μm 2 More than 50μm 2By doing the following, even when the thickness of the metal plate is 30 μm or less, the metal plate can be given strength and weldability, similar to the embodiment described above. This makes it possible to suppress the formation of localized deformations such as dents in the metal plate during the manufacturing process of the vapor deposition mask 20 and during handling of the vapor deposition mask 20. In addition, it is possible to suppress the formation of defects such as cracks in the vapor deposition mask 20 or the frame 15 when welding the vapor deposition mask 20 to the frame 15. [Example]

[0148] Next, embodiments of the present disclosure will be described in more detail by reference to examples, but embodiments of the present disclosure are not limited to the following examples unless they exceed the gist of the disclosure.

[0149] (Example 1) First, a metal sheet 64 with a thickness of 40 μm was prepared by rolling, consisting of an iron alloy containing 36 mass% nickel, the remainder being iron, and unavoidable impurities. The thickness of the metal sheet before rolling was 100 μm. Therefore, the reduction ratio was 60%.

[0150] Next, the EBSD pattern was measured using the EBSD method described above. Furthermore, the average cross-sectional area of ​​the crystal grains appearing in the cross-section of the metal plate 64 was calculated by analyzing the EBSD pattern. The result showed an average cross-sectional area of ​​113.4 μm². 2 It was.

[0151] The measurement conditions using the EBSD method are as follows: Magnification of observation with SEM: 2000x or 5000x (the standard magnification for observation when taking photographs is Polaroid 545) • Acceleration voltage in SEM: 15kV Working distance in SEM: 15 mm • Sample tilt angle φ1: 70 degrees EBSD step size (at 2000x SEM magnification): 70 nm EBSD step size (at SEM magnification of 5000x): 50 nm

[0152] The magnification of the SEM observation is explained in detail below. When the average cross-sectional area of ​​the crystal grains is large, the magnification of the SEM observation is set to 2000 times. Specifically, when the average cross-sectional area of ​​the crystal grains is 2 μm 2 In the cases described above (cases 1 to 8 and 10 to 14 described later), the magnification of the SEM was set to 2000x. When the observation magnification with the SEM is 2000x (the observation magnification standard during imaging is Polaroid 545), the image size is approximately 60 μm × approximately 45 μm. In this case, the cross-section of the metal plate 64 is measured so that the direction of the approximately 45 μm dimension coincides with the thickness direction of the metal plate 64. Therefore, the area of ​​the cross-section of the metal plate 64 that appears in one image (hereinafter referred to as the effective measurement area) is "thickness of the metal plate 64 (13~40 μm) × approximately 60 μm". When the number of crystal grains appearing in the effective measurement area was less than 1,000, images were acquired at multiple positions on the cross section of metal plate 64 while shifting the measurement area by approximately 50 μm, and an image showing more than 1,000 crystal grains was generated by connecting the multiple images obtained.

[0153] When the average cross-sectional area of ​​the crystal grains was small, the magnification for SEM observation was set to 5000x. Specifically, when the average cross-sectional area of ​​the crystal grains was 2 μm 2 In cases less than (as described later in cases 9, 15, and 16), the magnification used for SEM observation was set to 5000x. When the observation magnification with the SEM is 5000 times (the observation magnification standard during photography is Polaroid 545), the size of the image is approximately 24 μm × approximately 18 μm. In this case, the cross section of the metal plate 64 is measured so that the direction of the dimension of approximately 18 μm coincides with the thickness direction of the metal plate 64. The average cross-sectional area of ​​the crystal grains is 2 μm. 2 When the value was less than 1000, it was possible to observe more than 1000 crystal grains in a single measurement (single image), so there was no need to stitch together multiple images.

[0154] For analyzing the EBSD pattern, we used OIM (Ver7.3), a crystal orientation analysis software manufactured by TSL Solutions Co., Ltd. In the EBSD pattern analysis process, analysis was performed using the area method under the condition that areas with a difference in crystal orientation of 5 degrees or more were recognized as grain boundaries. Furthermore, data with a CI value of 0.15 or less, as defined by the crystal orientation analysis software OIM (Version 7.3), was excluded during the analysis process. This allows for the elimination of the influence of the resin used in pretreatment on the front and back of the sample, as well as the grain boundaries and amorphous regions present in the cross section of the sample. In the area method analysis, the average cross-sectional area of ​​crystal grains with a CI value greater than 0.15 was calculated using the area fraction method, and this was taken as the average cross-sectional area of ​​the crystal grains. In the area fraction method, if the total area of ​​the measurement region containing crystals with cross-sectional areas a, b, c, and d is 100, the average cross-sectional area is calculated taking into account area weighting as shown in the following formula (1). Average cross-sectional area=(a×a / 100)+(b×b / 100)+(c×c / 100)+(d×d / 100)...(1) In the following description, the average cross-sectional area of ​​crystal grains calculated by performing an area method analysis using the Area Fraction method after excluding data with a CI value of 0.15 or less is also referred to as the area-average cross-sectional area. The above-mentioned average cross-sectional area, the preferred range of which is determined by the above-mentioned first threshold, second threshold, etc., is the area-average cross-sectional area.

[0155] The average cross-sectional area of ​​crystal grains calculated by analyzing using the Number method after eliminating data with a CI value of 0.15 or less is also referred to as the number-average cross-sectional area. For the calculation of the number-average cross-sectional area, as with the area-average cross-sectional area, the EBSD pattern was analyzed using the crystal orientation analysis software OIM (Ver. 7.3) from TSL Solutions, Inc. The analysis was also performed by eliminating data with a CI value of 0.15 or less, as defined by the crystal orientation analysis software OIM (Ver. 7.3), under the condition that areas with a difference in crystal orientation of 5 degrees or more were recognized as grain boundaries. The average cross-sectional area of ​​crystal grains with a CI value greater than 0.15, calculated using the Number method, was used as the number-average cross-sectional area of ​​the crystal grains. While the area fraction method calculates the average cross-sectional area by taking into account area weighting, the Number method calculates the average cross-sectional area by considering all crystal grains under analysis with the same weight regardless of area.

[0156] Next, a deposition mask 20 was manufactured using the metal plate 64. Thereafter, the strength of the metal plate 64 constituting the deposition mask 20 was evaluated. Specifically, the deposition mask 20 was irradiated with light L1 as shown in FIG. 17 to observe whether or not a deformed portion 28 such as a dent was present on the surface of the obtained deposition mask 20. As a result, no deformed portion 28 was present.

[0157] The observation conditions for the surface of the deposition mask 20 are as follows. Light L1 brightness: 500lux~2000lux, e.g. 1000lux Light source for light L1: Three-wavelength fluorescent lamp Incident angle of light L1: 15 degrees to 45 degrees Distance from the light source to the surface of the deposition mask: 30cm~100cm, e.g. 50cm Distance from viewpoint to deposition mask surface: 15cm

[0158] Next, the weldability of the vapor deposition mask 20 was evaluated. Specifically, the ear portions 17 of the vapor deposition mask 20 were irradiated with laser light L2 and welded to the frame 15, and the weld strength between the ear portions 17 and the frame 15 was measured. The conditions for welding the ear portions 17 to the frame 15 were as follows. Laser light L2 wavelength: 355nm Laser beam L2 spot diameter: 200 μm Laser light L2 output: 0.3kW Laser light L2 irradiation time: 0.3 ms

[0159] The weld strength is the magnitude of the force required to peel the edge 17 of the deposition mask 20, which is welded to the frame 15 by the weld 19, from the frame 15. FIG. 24 shows an example of a method for measuring the weld strength of the weld 19. In the weld strength measurement process, first, a sample 17S obtained by cutting out a portion of the edge 17 of the deposition mask 20 is welded to the frame 15. Next, as shown in FIG. 24, a tensile force E is applied to an end of the longitudinal direction of the sample 17S in a direction normal to the frame 15. In this case, the tensile force E at which the sample 17S breaks or peels off from the frame 15 is the weld strength of the weld 19. The longitudinal direction of the sample 17S is parallel to the rolling direction D1 of the metal plate 64. The deposition mask 20 is generally manufactured from the metal plate 64 so that the longitudinal direction of the deposition mask 20 is parallel to the rolling direction D1 of the metal plate 64. Therefore, the rolling direction D1 can be recognized based on the longitudinal direction of the deposition mask 20.

[0160] The deposition mask 20 may be manufactured from the metal plate 64 so that the longitudinal direction of the deposition mask 20 is non-parallel to the rolling direction D1 of the metal plate 64. In this case, the rolling direction D1 may be determined based on the direction in which crystal grains of the metal plate 64 extend. This is because, in the metal plate 64 manufactured by rolling, the crystal grains extend parallel to the rolling direction D1.

[0161] Seven samples 17S were prepared from one deposition mask 20, and the weld strength of each sample 17S was measured. The average weld strength was 157 mN. Additionally, cracks were formed at the boundary between the welded area 19 and the surrounding area.

[0162] (Cases 2 to 16) Metal plates 64 according to Examples 2 to 16 were produced by changing at least one of the thickness, composition, or manufacturing conditions of the metal plate from that of Example 1 described above. The thickness of the metal plate 64 in each example is as follows. In Examples 1 to 8 and Examples 10 to 14, the metal plate 64 was produced by rolling an iron alloy base material. On the other hand, in Examples 9, 15, and 16, the metal plate 64 was produced by a foil-making process utilizing a plating treatment. For the examples in which the metal plate 64 was produced by rolling, the thickness T1 of the metal plate before rolling and the rolling reduction are shown below, along with the thickness T2 of the metal plate after rolling. ·Second example: T1=100μm, T2=35μm, reduction rate=65% ·Third example: T1=100μm, T2=30μm, reduction rate=70% ·4th example: T1=75μm, T2=30μm, reduction rate=60% ·5th example: T1=100μm, T2=25μm, reduction rate=75% ·6th example: T1=50μm, T2=20μm, reduction rate=60% ·7th example: T1=80μm, T2=20μm, reduction rate=75% ·8th example: T1=100μm, T2=20μm, reduction rate=80% ·9th example: 20μm ·10th example: T1=37.5μm, T2=15μm, reduction rate=60% ·11th example: T1=50μm, T2=15μm, reduction rate=70% ·12th example: T1=100μm, T2=15μm, reduction rate=85% ·13th example: T1=300μm, T2=15μm, reduction rate=95% ·14th example: T1=100μm, T2=13μm, reduction rate=87% • Examples 15-16: 10 μm

[0163] In addition, in the same manner as in Example 1, the area-average cross-sectional area and number-average cross-sectional area of ​​the crystal grains appearing in the cross section of the metal plate 64 according to Examples 2 to 16 were calculated. The results are summarized in Figure 25. In the "Judgment" column of Figure 25, "OK" indicates that the area-average cross-sectional area of ​​the crystal grains is 0.5 μm or more. 2 More than 50μm 2 This means the following: Also, "NG" indicates that the average cross-sectional area of ​​the crystal grains was 0.5 μm². 2 Less than or equal to 50 μm 2 This means that it exceeded

[0164] Furthermore, in the same manner as in Example 1, deposition masks 20 were produced using the metal plates 64 according to Examples 2 to 16. Then, in the same manner as in Example 1, the surfaces of the obtained deposition masks 20 were observed for the presence of deformed portions 28, such as dents. Furthermore, in the same manner as in Example 1, the ears 17 of the deposition masks 20 were welded to the frame 15, and the weld strength was measured. The results are summarized in FIG. 25.

[0165] In the 9th, 15th, and 16th examples, the area-average cross-sectional area of ​​the crystal grains of the metal plate 64 was 0.5 μm². 2 It was less than 200 mN. As a result, the weld strength was less than 200 mN. In addition, a crack was formed at the boundary between the welded part 19 and the surrounding area.

[0166] In the 4th, 6th, and 10th examples, the area-average cross-sectional area of ​​the crystal grains of the metal plate 64 was 50 μm². 2 It exceeded the limit. As a result, deformed areas 28, such as indentations, were present on the surface of the deposition mask 20.

[0167] In contrast, in the metal plates 64 with a thickness of 10 μm to 30 μm, as in the 3rd, 5th, 7th, 8th, and 11th to 14th examples, the area-average cross-sectional area of ​​the crystal grains is 0.5 μm. 2 More than 50μm 2As a result, the welding strength could be increased to 200 mN or more, more specifically, 220 mN or more. Furthermore, it was possible to prevent the formation of deformed portions 28 such as recesses on the surface of the deposition mask 20. In other words, it was possible to achieve both strength and weldability in the metal plate 64.

[0168] Furthermore, in the metal plate 64 with a thickness of 35 μm or more, as per the first and second examples, the area average cross-sectional area of ​​the crystal grains is 50 μm. 2 Although the thickness of the deposition mask 20 exceeded 50 μm, no deformed portions 28 such as depressions were formed on the surface of the deposition mask 20. It is considered that the thickness of the deposition mask 20 was large, and therefore the deposition mask 20 had a sufficiently high strength, so that no deformed portions 28 such as depressions were formed regardless of the area average cross-sectional area of ​​the crystal grains. Therefore, in this embodiment, when the area average cross-sectional area of ​​the crystal grains is set to 50 μm, 2 This criterion of 35 μm or more is particularly effective when the thickness of the metal plate 64 is 30 μm or less. Note that the metal plate 64 having a thickness of 35 μm or more as shown in the first and second examples is disadvantageous compared to the metal plate 64 having a thickness of 30 μm or less in that the utilization efficiency of the deposition material 98 in the deposition mask 20 made from the metal plate 64 is low.

[0169] FIG. 26 is a scatter plot in which data for the metal plate 64 according to each example is plotted, with the horizontal axis representing the thickness of the metal plate 64 and the vertical axis representing the area-average cross-sectional area of ​​the crystal grains of the metal plate 64. In FIG. 26, the "◯" marker indicates an example in which the welding strength was 200 mN or more and no deformed portion 28 was formed. The "△" marker indicates an example in which the welding strength was less than 200 mN. The "□" marker indicates an example in which the deformed portion 28 was formed. Furthermore, in FIG. 26, the area surrounded by the dotted line indicates an example in which the thickness of the metal plate 64 was 30 μm or less and the area-average cross-sectional area of ​​the crystal grains was 0.5 μm. 2 More than 50μm 2 The region is as follows. As is clear from Figure 26, in the region enclosed by the dotted line, the metal plate 64 was able to be given strength and weldability.

[0170] Figure 30 is a scatter plot of data for the metal plate 64 for each example, with the horizontal axis representing the thickness of the metal plate 64 and the vertical axis representing the number-average cross-sectional area of ​​the crystal grains of the metal plate 64. In Figure 30, the "○" marker indicates an example where the welding strength is 200 mN or more and no deformation portion 28 was formed. The "△" marker indicates an example where the welding strength is less than 200 mN. The "□" marker indicates an example where a deformation portion 28 was formed. Also in Figure 30, the area enclosed by the dotted line represents an example where the thickness of the metal plate 64 is 30 μm or less and the number-average cross-sectional area of ​​the crystal grains is 0.2 μm 2 Above 3.2μm 2 As is clear from Fig. 30, in the area surrounded by the dotted line, the metal plate 64 was able to have strength and weldability.

[0171] In the graph shown in Fig. 31, the horizontal axis and vertical axis respectively represent the area-average cross-sectional area and number-average cross-sectional area of ​​the crystal grains of the metal plates according to Examples 1 to 16. As can be seen from Fig. 31, the area-average cross-sectional area of ​​the crystal grains of the metal plates according to Examples 1 to 16 correlates with the number-average cross-sectional area. [Explanation of symbols]

[0172] 10. Evaporation mask device 15 frames 19 Welded section 20 Vapor deposition masks 22 Effective area 23 Surrounding Area 25 through holes 28 Deformed part 30 First recess 31 Wall surface 35 Second recess 36 Wall 41 Connection part 41a Missing part 43 Top section 50 test specimens 50c cross section 51 Crystal Grains 52. Grain boundaries 54 Crack 55 Resin 56 samples 57 Objective lens 58 EBSD detector 59 Manufacturing equipment 64 Metal plate 65a First resist pattern 65b Second resist pattern 70 Processing equipment 72 Transport roller 73 Separation device 90 Vapor deposition equipment 92 Organic EL board 98 Vapor Deposition Materials

Claims

[Claim 1] A deposition mask device, a deposition mask including a first surface and a second surface; The frame and a welding portion that connects the second surface of the deposition mask and the frame, the deposition mask is a metal plate that forms the first surface and the second surface, and a through hole that penetrates from the first surface to the second surface is formed in the metal plate; The welded portion is located at a central portion of the welded portion in a plan view and does not include a portion protruding from the first surface, The deposition mask device, wherein a welding strength between the deposition mask and the frame is 200 mN or more.

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