Metal plate for manufacturing vapor deposition mask, method for manufacturing metal plate, vapor deposition mask and method for manufacturing vapor deposition mask

Abstract

To provide a metal plate used for a vapor deposition mask and capable of enhancing accuracy in a shape of a formed open hole.SOLUTION: A metal plate used for manufacturing a vapor deposition mask, including a first surface and a second surface positioned on a side opposite to the first surface and including iron and nickel may include particles including an element except iron and nickel as a main component. A sample of the metal plate including the first and second surfaces may satisfy following conditions (1) and (2): (1) the number of particles having a circle equivalent diameter of 1 μm or more and included per volume 1 mm3 of the sample is 50 pieces or more and 3000 pieces or less; and (2) the number of particles having a circle equivalent diameter of 3 μm and included per volume 1 mm3 of the sample is 50 pieces or less.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] FIELD Embodiments of the present disclosure relate to a metal plate for manufacturing a deposition mask, a method for manufacturing a metal plate, a deposition mask, and a method for manufacturing a deposition mask. [Background technology]

[0002] In recent years, there has been a market demand for high-definition display devices for electronic devices such as smartphones, tablet PCs, etc. Display devices have a pixel density of, for example, 500 ppi or more, or 800 ppi or more.

[0003] Organic EL display devices have been attracting attention due to their good response and / or low power consumption. A method of attaching a material constituting the pixel to a substrate by vapor deposition is known as a method of forming pixels of an organic EL display device. In this case, a vapor deposition mask including a through hole is first prepared. Next, in a vapor deposition device, with the vapor deposition mask in close contact with the substrate, organic materials and / or inorganic materials are vapor deposited to form organic materials and / or inorganic materials on the substrate.

[0004] As a method for producing a deposition mask, for example as disclosed in Patent Document 1, a method is known in which through holes are formed in a metal plate by etching the metal plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5382259 Summary of the Invention [Problem to be solved by the invention]

[0006] An embodiment of the present disclosure aims to improve the accuracy of the shape of a through hole formed in a metal plate. [Means for solving the problem]

[0007] In one embodiment of the present disclosure, a metal plate used for manufacturing a deposition mask, which includes a first surface and a second surface opposite to the first surface, and which includes iron and nickel, may include particles containing an element other than iron and nickel as a main component. In a sample including the first surface and the second surface of the metal plate, the following conditions (1) and (2) may be satisfied. (1) Sample volume 1 mm 3 The number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 50 to 3,000. (2) Sample volume 1 mm 3 The number of particles having an equivalent circle diameter of 3 μm or more contained per unit area is 50 or less. Effect of the Invention

[0008] According to the embodiments of the present disclosure, the precision of the shape of a through hole formed in a metal plate can be improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a deposition apparatus including a deposition mask device according to an embodiment of the present disclosure. [Diagram 2] 2 is a cross-sectional view showing an organic EL display device manufactured using the deposition mask device shown in FIG. [Diagram 3] FIG. 1 is a plan view showing a deposition mask apparatus according to an embodiment of the present disclosure. [Figure 4] 4 is a partial plan view showing an effective area of ​​the deposition mask shown in FIG. 3. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 2 is a cross-sectional view showing an example of a metal plate provided with particles. [Figure 7] 7 is a cross-sectional view showing a step of providing a resist pattern on the metal plate shown in FIG. 6. [Figure 8] 7 is a cross-sectional view showing a step of forming a first recess by etching the metal plate shown in FIG. 6 from the first surface side. FIG. [Figure 9] FIG. 11 is a cross-sectional view showing a step of covering the first recess with resin. [Figure 10] 7 is a cross-sectional view showing a step of forming a second recess by etching the metal plate shown in FIG. 6 from the second surface side. FIG. [Figure 11] 10A to 10C are cross-sectional views showing a step of removing the resin and the resist pattern. [Figure 12] FIG. 2 is a cross-sectional view showing an example of a metal plate provided with particles. [Figure 13] 13 is a cross-sectional view showing a step of forming a first recess by etching the metal plate shown in FIG. 12 from the first surface side. FIG. [Figure 14] 13 is a cross-sectional view showing a step of forming a first recess by etching the metal plate shown in FIG. 12 from the first surface side. FIG. [Figure 15] FIG. 11 is a cross-sectional view showing a step of covering the first recess with resin. [Figure 16] 13 is a cross-sectional view showing a step of forming a second recess by etching the metal plate shown in FIG. 12 from the second surface side. FIG. [Figure 17] 10A to 10C are cross-sectional views showing a step of removing the resin and the resist pattern. [Figure 18] FIG. 2 is a cross-sectional view showing an example of a metal plate provided with particles. [Figure 19] 19 is a cross-sectional view showing a step of forming a first recess by etching the metal plate shown in FIG. 18 from the first surface side. [Figure 20] 19 is a cross-sectional view showing a step of forming a first recess by etching the metal plate shown in FIG. 18 from the first surface side. [Figure 21] FIG. 11 is a cross-sectional view showing a step of covering the first recess with resin. [Figure 22] 19 is a cross-sectional view showing a step of forming a second recess by etching the metal plate shown in FIG. 18 from the second surface side. [Figure 23] 19 is a cross-sectional view showing a step of forming a second recess by etching the metal plate shown in FIG. 18 from the second surface side. [Figure 24]10A to 10C are cross-sectional views showing a step of removing the resin and the resist pattern. [Diagram 25] 1 is a plan view showing a plurality of types of through holes formed in a metal plate as viewed from a first surface side. FIG. [Figure 26] FIG. 1 is a diagram showing a process for cutting a sample from a metal plate. [Figure 27] FIG. 13 is a diagram showing a process for punching out a plurality of sample pieces from a sample. [Figure 28] FIG. 13 is a diagram showing a process of dissolving a sample piece. [Figure 29] FIG. 2 is a plan view showing a number of particles distributed on a filter paper. [Diagram 30] FIG. 1 is a diagram for explaining a step of adjusting the contrast and / or brightness of a scanning electron microscope. [Diagram 31] FIG. 1 is a diagram for explaining a step of adjusting the contrast and / or brightness of a scanning electron microscope. [Diagram 32] FIG. 13 is a diagram for explaining a process for adjusting a brightness threshold value of analysis software. [Diagram 33] FIG. 13 is a diagram for explaining a process for adjusting a brightness threshold value of analysis software. [Diagram 34] FIG. 13 is a diagram for explaining the observation range of the filter paper. [Diagram 35] FIG. 1 is a diagram showing a process for analyzing the composition of particles. [Diagram 36] FIG. 1 shows an ingot of an iron alloy. [Figure 37] FIG. 1 is a diagram showing a process of removing a surface portion of an ingot. [Figure 38] FIG. 2 is a diagram showing a process for rolling a base material to obtain a metal plate having a desired thickness. [Figure 39] FIG. 2 is a diagram showing a process of annealing a metal plate obtained by rolling. [Diagram 40] 1A to 1C are schematic diagrams for generally explaining an example of a method for manufacturing a deposition mask. [Diagram 41] 1A to 1C are diagrams illustrating a process of forming a resist pattern on a metal plate. [Diagram 42] FIG. 11 is a diagram showing a first surface etching step. [Diagram 43] FIG. 11 is a diagram showing a second surface etching step. [Diagram 44] 11A to 11C are schematic views for explaining a first modified example of the method for manufacturing a deposition mask. [Diagram 45] 13A to 13C are views for explaining a second modified example of the method for manufacturing a deposition mask. [Diagram 46] 13A to 13C are views for explaining a second modified example of the method for manufacturing a deposition mask. [Figure 47] 13A to 13C are views for explaining a second modified example of the method for manufacturing a deposition mask. [Figure 48] FIG. 13 is a diagram showing the results of observing particles contained in each sample obtained from the first mask to the seventeenth mask. [Figure 49] FIG. 1 is a diagram showing the results of analyzing the composition of particles. [Figure 50] FIG. 13 shows the results of observing particles contained in each sample obtained from multiple locations on the roll in supplementary evaluation 1. [Figure 51] FIG. 13 shows the results of analyzing the particle composition in Supplementary Evaluation 1. [Figure 52] FIG. 13 shows the results of analyzing the particle composition in Supplementary Evaluation 2. [Figure 53] FIG. 13 shows the results of analyzing the particle composition in Supplementary Evaluation 2. [Figure 54] FIG. 2 is a cross-sectional view showing an example of a metal plate provided with particles. [Figure 55] 55 is a cross-sectional view showing a step of forming a first recess by etching the metal plate shown in FIG. 54 from the first surface side. FIG. [Figure 56] 55 is a cross-sectional view showing a step of forming a first recess by etching the metal plate shown in FIG. 54 from the first surface side. FIG. [Figure 57] FIG. 11 is a cross-sectional view showing a step of covering the first recess with resin. [Figure 58] 55 is a cross-sectional view showing a step of forming a second recess by etching the metal plate shown in FIG. 54 from the second surface side. FIG. [Figure 59]10A to 10C are cross-sectional views showing a step of removing the resin and the resist pattern. [Figure 60] FIG. [Figure 61] 1A to 1C are diagrams showing a process of removing a surface portion of a metal plate. [Figure 62] 13 is a diagram for explaining a method for evaluating the relative value of the area of ​​a through hole. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In this specification and the drawings, unless otherwise specified, terms that mean a material that is the basis of a certain configuration, such as "substrate", "base material", "plate", "sheet", and "film", are not distinguished from each other based only on the difference in name. In this specification and the drawings, unless otherwise specified, terms that specify shapes and geometric conditions and their degrees, such as "parallel" and "orthogonal", and values ​​of lengths and angles, are not bound by strict meanings, but are interpreted to include a range within which similar functions can be expected.

[0011] In this specification and drawings, unless otherwise specified, when a certain configuration such as a certain member or a certain region is described as being "on" or "under", "upper" or "lower" or "above" or "below" another configuration such as another member or another region, this includes the case where the certain configuration is in direct contact with the other configuration. It also includes the case where another configuration is included between a certain configuration and the other configuration, that is, where the configuration is indirectly in contact. Furthermore, unless otherwise specified, the words "on", "upper side", "upper", or "lower", "lower side", and "lower" may be used in the up-down direction.

[0012] In this specification and drawings, unless otherwise specified, the same or similar parts or parts having similar functions are denoted by the same or similar symbols, and repeated explanations may be omitted. In addition, the dimensional ratios of the drawings may differ from the actual ratios for the convenience of explanation, and some components may be omitted from the drawings.

[0013] In this specification and drawings, unless otherwise specified, the embodiments of the present disclosure may be combined with other embodiments or modifications as long as no contradictions arise. In addition, other embodiments may be combined with each other, or other embodiments and modifications may be combined as long as no contradictions arise. In addition, modifications may be combined as long as no contradictions arise.

[0014] In this specification and drawings, unless otherwise specified, when a plurality of steps are disclosed in a method such as a manufacturing method, other steps that are not disclosed may be performed between the disclosed steps. In addition, the order of the disclosed steps is arbitrary within the range that does not cause contradiction.

[0015] In this specification and drawings, unless otherwise specified, a range expressed by the symbol "to" includes the numerical values ​​and elements placed 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". For example, the range defined by the expression "through holes 25A to 25E" includes through holes 25A, 25B, 25C, 25D, and 25E.

[0016] In one embodiment of the present specification, an example related to a deposition mask used for patterning an organic material on a substrate in a desired pattern when manufacturing an organic EL display device and a manufacturing method thereof will be described. However, the present embodiment can be applied to deposition masks used for various purposes without being limited to such applications. For example, the deposition mask of the present embodiment may be used to manufacture a device for displaying or projecting images or videos for expressing virtual reality, so-called VR, or augmented reality, so-called AR.

[0017] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the embodiment described below is an example of the present disclosure, and the present disclosure is not to be interpreted as being limited to only these embodiments.

[0018] A first aspect of the present disclosure is a metal plate used for manufacturing a deposition mask, the metal plate including a first surface and a second surface located opposite to the first surface, the metal plate including iron and nickel, The particle includes an element other than iron and nickel as a main component, In a sample including the first surface and the second surface of the metal plate, the following conditions (1) and (2) are satisfied: (1) The volume of the sample is 1 mm 3 the number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 50 to 3,000; (2) The volume of the sample is 1 mm 3 the number of said particles having an equivalent circle diameter of 3 μm or more contained per unit area is 50 or less; It is a metal plate.

[0019] In a second aspect of the present disclosure, in the metal plate according to the above-mentioned first aspect, the following condition (3) may be satisfied. (3) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 1000 or less.

[0020] A third aspect of the present disclosure is such that, in the metal plate according to the first aspect or the second aspect described above, the following condition (4) may be satisfied. (4) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 3 μm or more contained per unit area is 20 or less.

[0021] A fourth aspect of the present disclosure may be such that, in the metal plate according to each of the first aspect to the third aspect described above, the following condition (5) is satisfied. (5) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 5 μm or more contained per unit area is 20 or less.

[0022] A fifth aspect of the present disclosure may be such that, in the metal plate according to each of the first to third aspects described above, the following condition (6) is satisfied. (6) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 5 μm or more contained per unit area is 2 or less.

[0023] A sixth aspect of the present disclosure may be such that, in the metal plate according to each of the first aspect to the fifth aspect described above, a first ratio of the metal plate is 70% or more. The first ratio is a ratio of the first quantity to the total quantity of the particles having an equivalent circle diameter of 1 μm or more. The total quantity is calculated based on the volume of the sample. 3 This is the number of particles having an equivalent circle diameter of 1 μm or more contained per unit area. The first quantity is equal to 1 mm of volume of the sample. 3 This is the number of particles having an equivalent circle diameter of 1 μm or more and less than 3 μm contained per unit area.

[0024] A seventh aspect of the present disclosure is a metal plate according to each of the first to sixth aspects described above, wherein the metal plate has a thickness of 70 μm or less.

[0025] An eighth aspect of the present disclosure is a metal plate according to each of the first to sixth aspects described above, wherein the metal plate has a thickness of 50 μm or less.

[0026] A ninth aspect of the present disclosure is a metal plate according to each of the first to sixth aspects described above, wherein the metal plate has a thickness of 30 μm or less.

[0027] A tenth aspect of the present disclosure is a method for producing a metal plate used for producing a deposition mask, the metal plate including a first surface and a second surface located on an opposite side to the first surface, the method comprising: A preparation step of preparing a base material having an iron alloy containing nickel; and rolling the base material to produce the metal plate. The metal plate includes particles containing an element other than iron and nickel as a main component, In a sample including the first surface and the second surface of the metal plate, the following conditions (1) and (2) are satisfied: (1) The volume of the sample is 1 mm 3 the number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 50 to 3,000; (2) The volume of the sample is 1 mm 3 the number of said particles having an equivalent circle diameter of 3 μm or more contained per unit area is 50 or less; A method for manufacturing a metal plate.

[0028] An eleventh aspect of the present disclosure is a method for manufacturing a metal plate according to the tenth aspect described above, wherein the manufacturing method may include a surface treatment step of removing a surface portion of the base material or the metal plate.

[0029] A twelfth aspect of the present disclosure is a method for manufacturing a metal plate according to the eleventh aspect described above, wherein the surface treatment process includes a base material surface treatment process for removing the surface portion of the base material, and the thickness of the surface portion may be 10 mm or more.

[0030] A thirteenth aspect of the present disclosure is a method for manufacturing a metal plate according to the eleventh aspect described above, wherein the surface treatment step includes a metal plate surface treatment step of removing the surface portion of the metal plate, and the thickness of the surface portion may be 5 μm or more.

[0031] A fourteenth aspect of the present disclosure is a method for manufacturing a metal plate according to the eleventh aspect described above, wherein the surface treatment step may include a step of removing the surface portion by contacting a surface treatment liquid with the surface of the base material or the metal plate.

[0032] A fifteenth aspect of the present disclosure may include, in the method for manufacturing a metal plate according to each of the tenth to fourteenth aspects described above, a sorting step of selecting the metal plate that satisfies the following conditions (1) and (2). (1) The volume of the sample is 1 mm 3 The number of the particles having an equivalent circle diameter of 1 μm or more contained per unit area is 50 to 3,000. (2) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 3 μm or more contained per unit area is 50 or less.

[0033] A sixteenth aspect of the present disclosure is such that, in the method for manufacturing a metal sheet according to each of the tenth aspect to the fifteenth aspect described above, the following condition (3) may be satisfied. (3) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 1000 or less.

[0034] A seventeenth aspect of the present disclosure is such that, in the method for manufacturing a metal sheet according to each of the tenth to sixteenth aspects described above, the following condition (4) may be satisfied. (4) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 3 μm or more contained per unit area is 20 or less.

[0035] An eighteenth aspect of the present disclosure is a method for manufacturing a metal sheet according to any one of the tenth to seventeenth aspects described above, wherein the following condition (5) is satisfied. (5) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 5 μm or more contained per unit area is 20 or less.

[0036] A nineteenth aspect of the present disclosure is a method for manufacturing a metal sheet according to any one of the tenth to eighteenth aspects described above, wherein the following condition (6) is satisfied. (6) The volume of the sample is 1 mm 3 The number of particles having an equivalent circle diameter of 5 μm or more contained per unit area is 2 or less.

[0037] A twentieth aspect of the present disclosure may be such that, in the method for manufacturing a metal plate according to each of the tenth aspect to the nineteenth aspect described above, a first ratio of the metal plate is 70% or more. The first ratio is a ratio of the first quantity to the total quantity of the particles having an equivalent circle diameter of 1 μm or more. The total quantity is calculated based on the volume of the sample. 3 This is the number of particles having an equivalent circle diameter of 1 μm or more contained per unit area. The first quantity is equal to 1 mm of volume of the sample. 3 This is the number of particles having an equivalent circle diameter of 1 μm or more and less than 3 μm contained per unit area.

[0038] A twenty-first aspect of the present disclosure is directed to the method for manufacturing a metal plate according to each of the tenth to twentieth aspects described above, wherein the metal plate has a thickness of 70 μm or less.

[0039] A twenty-second aspect of the present disclosure is directed to the method for manufacturing a metal plate according to each of the tenth to twentieth aspects described above, wherein the metal plate has a thickness of 50 μm or less.

[0040] A twenty-third aspect of the present disclosure may be such that, in the method for manufacturing a metal plate according to each of the tenth to twentieth aspects described above, the metal plate has a thickness of 30 μm or less.

[0041] A twenty-fourth aspect of the present disclosure is a deposition mask, comprising: a metal plate including a first surface and a second surface opposite the first surface, the metal plate comprising iron and nickel; A plurality of through holes formed in the metal plate, The metal plate includes particles containing an element other than iron and nickel as a main component, In a sample including the first surface and the second surface of the metal plate, the following conditions (1) and (2) are satisfied: (1) The volume of the sample is 1 mm 3the number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 50 to 3,000; (2) The volume of the sample is 1 mm 3 the number of said particles having an equivalent circle diameter of 3 μm or more contained per unit area is 50 or less; This is a deposition mask.

[0042] A twenty-fifth aspect of the present disclosure is a method for manufacturing a deposition mask, comprising: providing a metal plate comprising a first surface and a second surface opposite the first surface, the metal plate comprising iron and nickel; A processing step of forming a plurality of through holes in the metal plate, The metal plate includes particles containing an element other than iron and nickel as a main component, In a sample including the first surface and the second surface of the metal plate, the following conditions (1) and (2) are satisfied: (1) The volume of the sample is 1 mm 3 the number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 50 to 3,000; (2) The volume of the sample is 1 mm 3 the number of said particles having an equivalent circle diameter of 3 μm or more contained per unit area is 50 or less; This is a method for manufacturing a deposition mask.

[0043] First, a deposition apparatus 90 for performing a deposition process for depositing a deposition material on a target object will be described with reference to FIG. 1. As shown in FIG. 1, the deposition apparatus 90 may include therein a deposition source 94, a heater 96, and a deposition mask device 10. The deposition apparatus 90 further includes an exhaust means for creating a vacuum atmosphere inside the deposition apparatus 90. The deposition source 94 is, for example, a crucible. The deposition source 94 contains a deposition material 98 such as an organic light-emitting material. The heater 96 heats the deposition source 94 to evaporate the deposition material 98 under a vacuum atmosphere. The deposition mask device 10 may be disposed to face the deposition source 94.

[0044] The deposition mask device 10 will be described below. As shown in FIG. 1, the deposition mask device 10 may include at least one deposition mask 20 and a frame 15 that supports the deposition mask 20. The frame 15 may support the deposition mask 20 in a state in which the deposition mask 20 is pulled in the direction of its surface so that the deposition mask 20 does not bend. As shown in FIG. 1, the deposition mask device 10 may be disposed in a deposition device 90 such that the deposition mask 20 faces a substrate, for example, an organic EL substrate 92, which is an object to which the deposition material 98 is to be attached. In the following description, of the surfaces of the deposition mask 20, a surface on the organic EL substrate 92 side is referred to as a first surface 20a, and a surface located opposite to the first surface 20a is referred to as a second surface 20b.

[0045] 1, the deposition mask device 10 may include a magnet 93 arranged on the surface 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 side by magnetic force, and the deposition mask 20 can be closely attached to the organic EL substrate 92. Although not shown, the deposition mask 20 may be closely attached to the organic EL substrate 92 using an electrostatic chuck that utilizes electrostatic force (Coulomb force).

[0046] Fig. 3 is a plan view showing the deposition mask device 10 as viewed from the first surface 20a side of the deposition mask 20. As shown in Fig. 3, the deposition mask device 10 includes a plurality of deposition masks 20. Each deposition mask 20 includes a pair of long sides 26 and a pair of short sides 27, and has, for example, a rectangular shape. Each deposition mask 20 is fixed to a frame 15 at the pair of short sides 27 or portions in the vicinity thereof, for example, by welding.

[0047] The deposition mask 20 includes a metal plate in which a plurality of through holes 25 are formed penetrating the deposition mask 20. The deposition material 98 that evaporates from the deposition source 94 and reaches the deposition mask device 10 passes through the through holes 25 of the deposition mask 20 and adheres to the organic EL substrate 92. This allows the deposition material 98 to be formed into a film 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.

[0048] FIG. 2 is a cross-sectional view showing an organic EL display device 100 manufactured using the deposition apparatus 90 of FIG. 1. The organic EL display device 100 may include an organic EL substrate 92 and pixels including a deposition material 98 arranged in a pattern. Although not shown, the organic EL display device 100 may further include electrodes electrically connected to the pixels including the deposition material 98. The electrodes are provided in advance on the organic EL substrate 92, for example, before the deposition material 98 is attached to the organic EL substrate 92 by the deposition process. The organic EL display device 100 may further include other components, such as a sealing member that seals the space around the pixels including the deposition material 98 from the outside. Therefore, the organic EL display device 100 of FIG. 2 can also be said to be an organic EL display device intermediate generated at an intermediate stage in manufacturing an organic EL display device.

[0049] When a color display using a plurality of colors is desired, deposition apparatuses 90 equipped with deposition masks 20 corresponding to the respective colors are prepared, and the organic EL substrates 92 are sequentially placed in each deposition apparatus 90. In this way, for example, a red organic light-emitting material, a green organic light-emitting material, and a blue organic light-emitting material can be sequentially deposited on the organic EL substrate 92.

[0050] The deposition process may be performed inside a deposition apparatus 90 in a high-temperature atmosphere. In this case, the deposition mask 20, the frame 15, and the organic EL substrate 92 held inside the deposition apparatus 90 are also heated during the deposition process. At this time, the deposition mask 20, the frame 15, and the organic EL substrate 92 exhibit dimensional change behavior based on their respective thermal expansion coefficients. Therefore, it is preferable that the thermal expansion coefficients of the deposition mask 20 and the frame 15 are equal to the thermal expansion coefficient of the organic EL substrate 92. This can prevent a difference in the dimensional change rates of the deposition mask 20, the frame 15, and the organic EL substrate 92 based on the thermal expansion coefficients from occurring. Therefore, it can prevent the dimensional accuracy and positional accuracy of the deposition material attached to the organic EL substrate 92 from decreasing due to the thermal expansion of the deposition mask 20, the frame 15, the organic EL substrate 92, and the like.

[0051] For example, when a glass substrate is used as the organic EL substrate 92, an iron alloy containing nickel may be used as a main material of 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 nickel and cobalt in total of 28% by mass or more and 54% by mass or less and containing cobalt in total of 0% by mass or more and 6% by mass or less may be used as a material of the metal plate constituting the deposition mask 20. The total content of nickel and cobalt in the metal plate may be 28% by mass or more and 38% by mass or less. In this case, specific examples of the iron alloy containing nickel or nickel and cobalt include Invar, Super Invar, and Ultra Invar. Invar is an iron alloy containing 34% by mass or more and 38% by mass or less of nickel, the balance being iron and unavoidable impurities. Super Invar is an iron alloy containing 30% by mass or more and 34% by mass or less of nickel, cobalt, and the balance being iron and unavoidable impurities. Ultra Invar is an iron alloy containing 28% by mass or more and 34% by mass or less of nickel, 2% by mass or more and 7% by mass or less of cobalt, 0.1% by mass or more and 1.0% by mass or less of manganese, 0.10% by mass or less of silicon, 0.01% by mass or less of carbon, and the balance being iron and unavoidable impurities. The total content of nickel and cobalt in the metal sheet may be 38% by mass or more and 54% by mass or less. In this case, a specific example of the iron alloy containing nickel or nickel and cobalt is a low thermal expansion Fe-Ni-based plated alloy. The low thermal expansion Fe-Ni-based plated alloy is an iron alloy containing 38% by mass or more and 54% by mass or less of nickel, with the balance being iron and unavoidable impurities.

[0052] If the temperatures of the deposition mask 20, the frame 15, and the organic EL substrate 92 do not reach high temperatures during deposition processing, there is no particular need to set the thermal expansion coefficients of the deposition mask 20 and the frame 15 to values ​​equivalent to the thermal expansion coefficient of the organic EL substrate 92. In this case, a material other than the above-mentioned iron alloy may be used as a material constituting the deposition mask 20. For example, an iron alloy other than the above-mentioned iron alloy containing nickel, such as an iron alloy containing chromium, may be used. As the iron alloy containing chromium, for example, an iron alloy so-called stainless steel may be used. An alloy other than an iron alloy, such as nickel or a nickel-cobalt alloy, may be used.

[0053] Next, the deposition mask 20 will be described in detail. As shown in Fig. 3, the deposition mask 20 may include a first end portion 17a and a second end portion 17b that face each other in a first direction D1 of the deposition mask 20, and an intermediate portion 18 located between the pair of ends 17a, 17b.

[0054] First, the ends 17a and 17b will be described in detail. The ends 17a and 17b are regions that extend from the ends of the deposition mask 20 in the first direction D1. The ends 17a and 17b have an area that allows a sample to be cut out, which will be described later. The ends 17a and 17b may be at least partially fixed to the frame 15. In this embodiment, the ends 17a and 17b are integrally formed with the intermediate portion 18. The ends 17a and 17b may be formed of a member different from the intermediate portion 18. In this case, the ends 17a and 17b are joined to the intermediate portion 18 by, for example, welding.

[0055] Next, the intermediate portion 18 will be described. The intermediate portion 18 includes 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 surrounding 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.

[0056] 3, the intermediate portion 18 includes a plurality of effective areas 22 arranged at predetermined intervals along the long side 26 of the deposition mask 20. One effective area 22 corresponds to the display area of ​​one organic EL display device 100. Therefore, the deposition mask device 10 shown in FIG. 1 allows deposition on multiple surfaces of the organic EL display device 100. One effective area 22 may correspond to a plurality of display areas. Although not shown, a plurality of effective areas 22 may also be arranged at predetermined intervals in the second direction D2 of the deposition mask 20.

[0057] 3, the effective area 22 has, for example, a substantially quadrangular shape in plan view, and more precisely, a substantially rectangular shape in plan view. Although not shown, each effective area 22 may have a contour of various shapes depending on the shape of the display area of ​​the organic EL substrate 92. For example, each effective area 22 may have a circular contour. Each effective area 22 may have a contour that is the same as the outer shape of a display device such as a smartphone.

[0058] Hereinafter, the effective area 22 will be described in detail. Fig. 4 is an enlarged plan view showing the effective area 22 from the second surface 20b side of the deposition mask 20. As shown in Fig. 4, in the illustrated example, the multiple through holes 25 formed in each effective area 22 may be arranged at a predetermined pitch in the effective area 22 along two directions perpendicular to each other.

[0059] FIG. 5 is a cross-sectional view along the VV direction of the effective area 22 of FIG. 4. As shown in FIG. 5, the through holes 25 penetrate from the first surface 20a, which is one side along the normal direction N of the deposition mask 20, to the second surface 20b, which is the other side along the normal direction N of the deposition mask 20. In the illustrated example, as described in detail later, the first recess 30 is formed by etching on the first surface 64a of the metal plate 64, which is one side in the normal direction N of the deposition mask 20, and the second recess 35 is formed on the second surface 64b of the metal plate 64, which is the other side in the normal direction N of the deposition mask 20. The first recess 30 is connected to the second recess 35, and the second recess 35 and the first recess 30 are formed so as to 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. In the example shown in Fig. 4 and 5, 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.

[0060] As shown in FIG. 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 the two adjacent second recesses 35. In the following description, the part of the effective area 22 of the second surface 64b of the metal plate 64 that remains without being etched is also referred to as a top portion 43. By producing the deposition mask 20 so that such a top portion 43 remains, it is possible to provide the deposition mask 20 with sufficient strength. This makes it possible to suppress damage to the deposition mask 20, for example, during transportation. If the width β of the top portion 43 is too large, a shadow may be generated in the deposition process, which may reduce the utilization efficiency of the deposition material 98. Therefore, it is preferable that the deposition mask 20 is fabricated so that the width β of the top portion 43 does not become excessively large.

[0061] When the deposition mask device 10 is accommodated in the deposition device 90 as shown in FIG. 1, 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 is located on the deposition source 94 side 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 from the second surface 20b side to the first surface 20a in FIG. 5, the deposition material 98 not only moves from the deposition source 94 toward the organic EL substrate 92 along the normal direction N of the organic EL substrate 92, but also moves in a direction greatly inclined with respect to the normal direction N of the organic EL substrate 92. At this time, 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, and as a result, the ratio of the deposition material 98 that cannot pass through the through-hole 25 increases. Therefore, in order to increase 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. That is, it can be said that it is preferable to use, as the metal plate 64 for constituting the deposition mask 20, a metal plate 64 having a thickness t as small as possible within a range in which the strength of the deposition mask 20 can be ensured. The thickness t is the thickness of the surrounding region 23, that is, the thickness of the part of the deposition mask 20 where the first recess 30 and the second recess 35 are not formed. Therefore, it can also be said that the thickness t is the thickness of the metal plate 64. The thickness t of the metal plate 64 may be, for example, 100 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, or 18 μm or less.

[0062] On the other hand, if the thickness t of the metal plate 64 is too small, the strength of the deposition mask 20 decreases and the deposition mask 20 is easily damaged or deformed. In consideration of this, the thickness t of the metal plate 64 may be, for example, 8 μm or more, 10 μm or more, 13 μm or more, or 15 μm or more.

[0063] The range of the thickness t of the metal plate 64 may be determined by a first group consisting of 8 μm, 10 μm, 13 μm, and 15 μm, and / or a second group consisting of 18 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, and 100 μm. The range of the thickness t of the metal plate 64 may be determined by a combination of any one of the values ​​included in the first group described above and any one of the values ​​included in the second group described above. The range of the thickness t of the metal plate 64 may be determined by a combination of any two of the values ​​included in the first group described above. The range of the thickness t of the metal plate 64 may be determined by a combination of any two of the values ​​included in the second group described above.For example, it may be 8 μm or more and 100 μm or less, 8 μm or more and 80 μm or less, 8 μm or more and 70 μm or less, 8 μm or more and 60 μm or less, 8 μm or more and 50 μm or less, 8 μm or more and 40 μm or less, 8 μm or more and 30 μm or less, 8 μm or more and 25 μm or less, 8 μm or more and 20 μm or less, 8 μm or more and 18 μm or less, or 8 μm or less. or less than 15 μm, or more than 8 μm and less than 13 μm, or more than 8 μm and less than 10 μm, or more than 10 μm and less than 30 μm, or more than 10 μm and less than 25 μm, or more than 10 μm and less than 20 μm, or more than 10 μm and less than 18 μm, or more than 10 μm and less than 15 μm, or more than 10 μm and less than 13 μm, or more than 13 μm and less than 30 μm, or more than 13 μm and less than 2 It may be 5 μm or less, it may be 13 μm or more and 20 μm or less, it may be 13 μm or more and 18 μm or less, it may be 13 μm or more and 15 μm or less, it may be 15 μm or more and 30 μm or less, it may be 15 μm or more and 25 μm or less, it may be 15 μm or more and 20 μm or less, it may be 15 μm or more and 18 μm or less, it may be 18 μm or more and 30 μm or less, it may be 18 μm or more and 25 μm or less, it may be 18 μm or more and It may be 20 μm or less, may be 20 μm or more and 30 μm or less, may be 20 μm or more and 25 μm or less, may be 25 μm or more and 30 μm or less, may be 30 μm or more and 100 μm or less, may be 40 μm or more and 100 μm or less, may be 50 μm or more and 100 μm or less, may be 60 μm or more and 100 μm or less, 70 μm or more and 100 μm or less, or may be 80 μm or more and 100 μm or less.

[0064] A contact-type measuring method is adopted as a method for measuring the thickness of the metal plate 64 and the deposition mask 20. For the contact-type measuring method, a length gauge "MT1271" of HEIDENHAIN-METRO manufactured by HEIDENHAIN AG, which is equipped with a ball bush guide type plunger, is used.

[0065] The metal plate 64 used in manufacturing the deposition mask 20 may be sold or transported in a state of being wound around a core, for example. In this case, the above-mentioned range for the thickness t of the metal plate 64 may be satisfied in the metal plate 64 in the wound state. When the manufacturing method of the deposition mask 20 includes a step of processing the metal plate 64 so as to reduce the thickness of the metal plate 64, the above-mentioned range for the thickness t of the metal plate 64 may be satisfied in the metal plate 64 in a state in which the thickness has been reduced by processing. The step of processing the metal plate 64 so as to reduce the thickness of the metal plate 64 includes, for example, a step of etching at least a portion of the first surface 64a or the second surface 64b of the metal plate 64 that corresponds to the effective region 22 of the deposition mask 20 over the entire area. Hereinafter, etching at least a portion of the metal plate 64 that corresponds to the effective region 22 over the entire area is also referred to as slimming.

[0066] When thinning the metal plate 64 by etching, if the reduction in thickness of the metal plate 64 is large, the thickness of the metal plate 64 after thinning is likely to vary. In consideration of this, even when thinning the metal plate 64, it is preferable that the thickness t of the metal plate 64 in a rolled state is small to a certain extent. For example, the thickness t of the metal plate 64 may be 50 μm or less, 45 μm or less, 40 μm or less, or 35 μm or less. The candidate upper limit value in this paragraph may be combined with the multiple candidate lower limit values ​​and the multiple candidate upper limit values ​​described above.

[0067] 5, the minimum angle that a straight line M1 passing through the connection portion 41 constituting the through portion 42 of the through hole 25 and any other position on the wall surface 36 of the second recess 35 forms with respect to the normal direction N of the deposition mask 20 is denoted by θ1. In order to allow the deposition material 98 moving obliquely 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 order to increase the angle θ1, it is also effective to reduce the width β of the top portion 43 described above, in addition to reducing the thickness t of the deposition mask 20.

[0068] 5, the symbol α represents the width of the portion (hereinafter also referred to as the rib portion) that remains unetched within the effective area 22 of the first surface 64a of the metal plate 64. The width α of the rib portion and the dimension r of the through portion 42 are appropriately determined according to the dimensions of the organic EL display device and the number of display pixels. 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.

[0069] The width α of the rib portion may be, for example, 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more. The width α of the rib portion may be, for example, 45 μm or less, 50 μm or less, 55 μm or less, or 60 μm or less. The range of the width α of the rib portion may be determined by a first group consisting of 5 μm, 10 μm, 15 μm, and 20 μm, and / or a second group consisting of 45 μm, 50 μm, 55 μm, and 60 μm. The range of the width α of the rib portion may be determined by a combination of any one of the values ​​included in the first group described above and any one of the values ​​included in the second group described above. The range of the width α of the rib portion may be determined by a combination of any two of the values ​​included in the first group described above. The range of the width α of the rib portion may be determined by a combination of any two of the values ​​included in the second group described above. For example, it may be 5 μm or more and 60 μm or less, 5 μm or more and 55 μm or less, 5 μm or more and 50 μm or less, 5 μm or more and 45 μm or less, 5 μm or more and 20 μm or less, 5 μm or more and 15 μm or less, 5 μm or more and 10 μm or less, 10 μm or more and 60 μm or less, 10 μm or more and 55 μm or less, 10 μm or more and 50 μm or less, 10 μm or more and 45 μm or less, 10 μm or more and 20 μm or less, 10 μm or more and 15 μm or less, 15 μm or more and 60 μm or less, or 1 It may be 5 μm or more and 55 μm or less, or 15 μm or more and 50 μm or less, or 15 μm or more and 45 μm or less, or 15 μm or more and 20 μm or less, or 20 μm or more and 60 μm or less, or 20 μm or more and 55 μm or less, or 20 μm or more and 50 μm or less, or 20 μm or more and 45 μm or less, or 45 μm or more and 60 μm or less, or 45 μm or more and 55 μm or less, or 45 μm or more and 50 μm or less, or 50 μm or more and 60 μm or less, or 50 μm or more and 55 μm or less, or 55 μm or more and 60 μm or less.

[0070] The dimension r of the through portion 42 may be, for example, 10 μm or more, 15 μm or more, 20 μm or more, or 25 μm or more. The dimension r of the through portion 42 may be, for example, 40 μm or less, 45 μm or less, 50 μm or less, or 55 μm or less. The range of the dimension r of the through portion 42 may be determined by a first group consisting of 10 μm, 15 μm, 20 μm, and 25 μm, and / or a second group consisting of 40 μm, 45 μm, 50 μm, and 55 μm. The range of the dimension r of the through portion 42 may be determined by a combination of any one of the values ​​included in the first group described above and any one of the values ​​included in the second group described above. The range of the dimension r of the through portion 42 may be determined by a combination of any two of the values ​​included in the first group described above. The range of the dimension r of the through portion 42 may be determined by a combination of any two of the values ​​included in the second group described above. For example, it may be 10 μm or more and 55 μm or less, 10 μm or more and 50 μm or less, 10 μm or more and 45 μm or less, 10 μm or more and 40 μm or less, 10 μm or more and 25 μm or less, 10 μm or more and 20 μm or less, 10 μm or more and 15 μm or more and 15 μm or more and 55 μm or less, 15 μm or more and 50 μm or less, 15 μm or more and 45 μm or less, 15 μm or more and 40 μm or less, 15 μm or more and 25 μm or less, 15 μm or more and 20 μm or more and 20 μm or more and 55 μm or less. Alternatively, it may be 20 μm or more and 50 μm or less, 20 μm or more and 45 μm or less, 20 μm or more and 40 μm or less, 20 μm or more and 25 μm or less, 25 μm or more and 55 μm or less, 25 μm or more and 50 μm or less, 25 μm or more and 45 μm or less, 25 μm or more and 40 μm or less, 40 μm or more and 55 μm or less, 40 μm or more and 50 μm or less, 40 μm or more and 45 μm or less, 45 μm or more and 55 μm or less, 45 μm or more and 50 μm or less, 50 μm or more and 55 μm or less.

[0071] 4 and 5 show an example in which the second surface 64b of the metal plate 64 remains between two adjacent second recesses 35, but the present invention 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 a place between two adjacent second recesses 35 where the second surface 64b of the metal plate 64 does not remain.

[0072] As a result of repeated research, the present inventors have found that as the pixel density of the deposition mask 20 increases, a plurality of particles contained in the metal plate 64 tends to adversely affect the accuracy of the shape of the through-holes 25 of the deposition mask 20. The cause will be considered below. Note that the cause of the above-mentioned phenomenon is not limited to the following consideration, and other considerations may be adopted.

[0073] First, the multiple particles contained in the metal plate 64 will be described. The inventors of the present invention conducted intensive research and found that multiple particles exist in the metal plate 64 made of an iron alloy containing iron and nickel, which is used in the manufacture of the deposition mask 20. The particles in the metal plate 64 are generated due to additives such as aluminum and silicon that are added to remove impurities during the melting process for preparing the base material of the metal plate 64. The particles contain elements other than iron and nickel as main components. Such particles are sometimes called inclusions. The "main component" refers to the element that has the highest weight % of the elements contained in the particles. The particles may be composed of a single element or a compound containing multiple elements. The "base material" refers to the form of the iron alloy before it is rolled. Examples of the base material are the first ingot, the second ingot, and the third ingot, which will be described later. The "metal plate" refers to the form of the iron alloy after the hot rolling process or the cold rolling process.

[0074] When the number of particles contained in the metal plate 64 is large or when the dimensions of the particles contained in the metal plate 64 are large, the shape of the through holes 25 formed in the metal plate 64 by etching may deviate from the design, as described below. Below, while describing part of the process of manufacturing the deposition mask 20 using the metal plate 64, the influence of the particles 64d in the metal plate 64 on the manufacturing process of the deposition mask 20 will be described.

[0075] First, a case will be described in which the influence of the particles in the metal plate 64 on the accuracy of the shape of the through-hole 25 of the deposition mask 20 is negligibly small. FIG. 6 is a cross-sectional view showing an example of a metal plate 64 including particles 64d. The metal plate 64 includes a main phase 64c and a plurality of particles 64d present in the main phase 64c. The main phase 64c includes a plurality of crystal grains made of an iron alloy including iron and nickel, for example. The iron alloy constituting the main phase 64c may include other elements such as cobalt in addition to iron and nickel. The range of the content of nickel and cobalt in the main phase 64c may be the same as the range described above for the material of the metal plate constituting the deposition mask 20.

[0076] The particles 64d are, for example, objects that are poorly soluble in nitric acid. The particles 64d contain elements other than iron and nickel as main components. For example, the particles 64d have aluminum, magnesium, silicon, phosphorus, sulfur, chromium, or zirconium, or compounds containing these elements. The compounds are, for example, oxides, sulfides, carbides, nitrides, intermetallic compounds, and the like. The shape of the particles 64d is arbitrary, but is, for example, granular.

[0077] 6, the particles 64d may be located inside the main phase 64c or on the surface of the main phase 64c. "Located on the surface of the main phase 64c" means that the particles 64d are at least partially exposed to the first surface 64a or the second surface 64b of the metal plate 64.

[0078] When the particles 64d are located inside the main phase 64c, the particles 64d may be located in a surface layer of the main phase 64c or in a bulk layer of the main phase 64c. The surface layer is a portion that is within 5 μm away from the first surface 64a or the second surface 64b of the metal plate 64 in the thickness direction. The bulk layer is a portion that is more than 5 μm away from the first surface 64a and the second surface 64b of the metal plate 64 in the thickness direction.

[0079] The plurality of particles 64d may be uniformly distributed in both the surface layer and the bulk layer of the main phase 64c. The plurality of particles 64d may be more distributed in the surface layer than in the bulk layer of the main phase 64c. The plurality of particles 64d may be more distributed in the bulk layer than in the surface layer of the main phase 64c.

[0080] 7, in the process of manufacturing the deposition mask 20, a first resist pattern 65c including a first resist film 65a is formed on a first surface 64a of a metal plate 64, and a second resist pattern 65d including a second resist film 65b is formed on a second surface 64b of the metal plate 64. Hereinafter, the process of forming the resist patterns 65c and 65d will be described.

[0081] First, resist films 65a, 65b containing a negative photosensitive resist material are 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 first surface 64a and the second surface 64b of the metal plate 64. The coating liquid is then dried to form the resist films 65a, 65b. Alternatively, the resist films 65a, 65b may be formed by attaching a dry film to the first surface 64a and the second surface 64b of the metal plate 64. The dry film contains, for example, an acrylic photocurable resin.

[0082] Next, an exposure mask that does not transmit light to the regions of the resist films 65a and 65b to be removed is prepared, and the exposure mask is placed on the resist films 65a and 65b. At this time, an alignment process may be performed to adjust the relative positional relationship between the exposure mask on the first surface 64a side and the exposure mask on the second surface 64b side. As the exposure mask, for example, a glass dry plate that does not transmit light to the regions of the resist films 65a and 65b to be removed is used. After that, the exposure mask may be sufficiently adhered to the resist films 65a and 65b by vacuum adhesion. The photosensitive resist material may be a positive type, in which case an exposure mask is used that allows light to pass through the area of ​​the resist film that is to be removed.

[0083] Thereafter, an exposure process is performed in which the resist films 65a, 65b are exposed through an exposure mask. Furthermore, a development process is performed in which the resist films 65a, 65b are developed to form an image on the exposed resist films 65a, 65b. In this manner, as shown in FIG. 7, a first resist pattern 65c including a first resist film 65a is formed on the first surface 64a of the metal plate 64, and a second resist pattern 65d including a second resist film 65b is formed on the second surface 64b of the metal plate 64. After the development process, a resist heat treatment process may be performed in which the resist films 65a, 65b are heated. This can increase the hardness of the resist films 65a, 65b and increase the adhesion of the resist films 65a, 65b to the metal plate 64. The resist heat treatment process may be performed at, for example, 25° C. or higher and 400° C. or lower. The resist heat treatment process for heating the resist films 65a, 65b may be carried out before the development process for developing the resist films 65a, 65b, in addition to or instead of the heat treatment process after the development process for developing the resist films 65a, 65b.

[0084] When the particles 64d are exposed on the surface of the metal plate 64, the resist films 65a, 65b contact not only the surface of the main phase 64c but also the particles 64d. Therefore, the contact area between the resist films 65a, 65b and the metal plate 64 can be increased compared to when the resist films 65a, 65b contact only the surface of the main phase 64c. This can contribute to improving the adhesion between the resist films 65a, 65b and the metal plate 64. The anchor effect of the particles 64d on the resist films 65a, 65b can also contribute to improving the adhesion between the resist films 65a, 65b and the metal plate 64.

[0085] Next, as shown in FIG. 8, a first surface etching step is performed in which the area of ​​the first surface 64a of the metal plate 64 that is not covered by the first resist film 65a is etched using a first etching liquid E1. For example, the first etching liquid E1 is sprayed toward the first surface 64a of the metal plate 64 from a nozzle disposed on the side facing the first surface 64a of the metal plate 64. As a result, as shown in FIG. 8, the area of ​​the metal plate 64 that is not covered by the first resist film 65a is eroded by the first etching liquid E1. By etching the area of ​​the first surface 64a of the metal plate 64 that is not covered by the first resist film 65a, a large number of first recesses 30 can be formed on the first surface 64a of the metal plate 64. As the first etching liquid E1, for example, one containing a ferric chloride solution and hydrochloric acid may be used.

[0086] 9, the first recess 30 is covered with a resin 69 having resistance to a second etching liquid used in a subsequent second surface etching step. For example, the first recess 30 is sealed with the resin 69 having resistance to the second etching liquid. As shown in FIG. 9, the film of the resin 69 may cover the first recess 30 as well as the first surface 64a and the first resist pattern 65c.

[0087] Next, as shown in FIG. 10, a second surface etching step is performed in which the second recesses 35 are formed on the second surface 64b by etching the area of ​​the second surface 64b of the metal plate 64 that is not covered by the second resist film 65b. For example, the second etching liquid E2 is sprayed toward the second surface 64b of the metal plate 64 from a nozzle disposed on the side facing the second surface 64b of the metal plate 64. As a result, as shown in FIG. 10, the area of ​​the metal plate 64 that is not covered by the second resist film 65b is eroded by the second etching liquid E2. By etching the area of ​​the second surface 64b of the metal plate 64 that is not covered by the second resist film 65b, a large number of second recesses 35 can be formed on the second surface 64b of the metal plate 64. The second surface etching step is performed until the first recesses 30 and the second recesses 35 communicate with each other, thereby forming the through holes 25. As the second etching liquid E2, for example, one containing a ferric chloride solution and hydrochloric acid may be used.

[0088] Next, as shown in Fig. 11, resin 69 is removed from metal plate 64. Resin 69 can be removed by using, for example, an alkaline stripper. When an alkaline stripper is used, resist films 65a, 65b may be removed simultaneously with resin 69, as shown in Fig. 11. After resin 69 is removed, resist films 65a, 65b may be removed separately from resin 69 using a stripper different from the stripper for stripping resin 69.

[0089] In this manner, a plurality of through holes 25 can be formed in the metal plate 64. In the following description, the through holes 25 formed without being affected by the particles 64d in the metal plate 64 are also referred to as standard through holes, and are denoted by the symbol 25A.

[0090] Next, a case will be described in which the dimension of the through hole 25 becomes smaller than that of the standard through hole 25A due to the influence of the particles 64d in the metal plate 64. In the following description of the manufacturing process of the deposition mask 20, duplicated descriptions of parts configured or implemented in the same manner as in the above-described embodiment shown in Figs.

[0091] FIG. 12 is a cross-sectional view showing an example of a metal plate 64 including a plurality of particles 64d. The metal plate 64 shown in FIG. 12 further includes particles having a circle equivalent diameter of 3 μm or more in addition to relatively small particles, for example, particles having a circle equivalent diameter of less than 3 μm. In the following description, particles 64d having a circle equivalent diameter of 3 μm or more may be specifically represented by the reference symbol 64e. In the example shown in FIG. 12, the particles 64e are present in the bulk layer of the metal plate 64. The particles 64e may also be present in the surface layer of the metal plate 64.

[0092] After forming resist films 65a, 65b on the first surface 64a and the second surface 64b of the metal plate 64, a first surface etching step is performed in which the area of ​​the first surface 64a of the metal plate 64 that is not covered by the first resist film 65a is etched using a first etching liquid E1, as shown in Fig. 13. As a result, as shown in Fig. 13, erosion by the first etching liquid E1 progresses in the area of ​​the metal plate 64 that is not covered by the first resist film 65a. Fig. 14 is a diagram showing a state in which erosion by the first etching liquid E1 has progressed further.

[0093] In the first surface etching step, when etching progresses to a location where the particles 64e are present, the particles 64e are exposed on the wall surface of the first recess 30 as shown in FIG. 13. When etching progresses from the state shown in FIG. 13, the particles 64e exposed on the wall surface may fall off the metal plate 64. In this case, a recess is formed in the wall surface of the first recess 30 where the particles 64e were present. In the recess, etching progresses deeper in the thickness direction of the metal plate 64 than in other parts. As a result, as shown on the right side of FIG. 14, it is considered that the first recess 30 formed by etching from the first surface 64a side of the metal plate 64 reaches the second surface 64b. Or, as shown on the left side of FIG. 14, it is considered that the first recess 30 formed by etching from the first surface 64a side of the metal plate 64 does not reach the second surface 64b but reaches a position close to the second surface 64b.

[0094] Thereafter, as shown in FIG. 15, the first recess 30 is covered with a resin 69 that is resistant to a second etching liquid used in a subsequent second surface etching step.

[0095] When the first recess 30 reaches the second surface 64b as shown in the right side of Fig. 14 described above, it is considered that the resin 69 penetrates the metal plate 64 and reaches the second surface 64b side as shown in the right side of Fig. 15. In this case, as shown in the right side of Fig. 15, a phenomenon may occur in which a layer of the resin 69 is formed in the gap between the second resist films 65b on the second surface 64b, that is, a part of the second surface 64b is covered with the layer of the resin 69.

[0096] Next, as shown in Fig. 16, a second surface etching step is performed in which a region of the second surface 64b of the metal plate 64 that is not covered by the second resist film 65b is etched to form a second recess 35 on the second surface 64b. As a result, as shown in Fig. 16, erosion by the second etching liquid E2 progresses in the region of the metal plate 64 that is not covered by the second resist film 65b.

[0097] As shown on the right side of Fig. 16, when a layer of resin 69 is formed in the gap between the second resist films 65b, etching of the second surface 64b is inhibited by the layer of resin 69. For this reason, as shown on the right side of Fig. 16, there may be a portion of the second surface 64b that is not covered by the second resist film 65b but is not etched at all. Alternatively, the layer of resin 69 may inhibit etching of the second surface 64b, so that the dimensions of the second recess 35 may become smaller than those of the standard through hole 25A.

[0098] 15 and 16, even if the resin 69 does not penetrate the metal plate 64 and reach the second surface 64b side, if an excess of the resin 69 is provided in the recess of the first recess 30, the flow of the second etching liquid E2 may be obstructed by the resin 69. In this case, the position of the connection portion 41 that connects the first recess 30 and the second recess 35 may be located closer to the second surface 64b than in the case of the standard through hole 25A.

[0099] 17, the resin 69 and the resist films 65a, 65b are removed from the metal plate 64. In this manner, a plurality of through holes 25 can be formed in the metal plate 64. In the following description, the through holes 25 having dimensions smaller than the standard through holes 25A due to the influence of particles in the metal plate 64 are also referred to as reduced through holes, and are represented by the reference numerals 25B and 25C.

[0100] 17, the through portion 42 where the opening area of ​​the reduced through hole 25B is the smallest is defined by the outline of the first recess 30 formed on the second surface 64b by the first-surface etching step reaching the second surface 64b. For this reason, the dimension SB of the through portion 42 of the reduced through hole 25B is significantly smaller than the dimension SA of the through portion 42 of the standard through hole 25A.

[0101] In the example on the left side of Fig. 17, the through portion 42 where the opening area of ​​the reduced through hole 25C is the smallest is formed by a connection portion 41 that connects the first recess 30 and the second recess 35. The position of the connection portion 41 of the reduced through hole 25C shown on the left side of Fig. 17 is located closer to the second surface 64b than in the case of the standard through hole 25A. Therefore, the dimension SC of the through portion 42 of the reduced through hole 25C is smaller than the dimension SA of the through portion 42 of the standard through hole 25A.

[0102] Next, a case will be described in which the dimension of the through hole 25 becomes larger than that of the standard through hole 25A due to the influence of particles in the metal plate 64. In the following description of the manufacturing process of the deposition mask 20, duplicated descriptions of parts configured or implemented in the same manner as in the above-described embodiment shown in Figs.

[0103] Fig. 18 is a cross-sectional view showing an example of a metal plate 64 containing a plurality of particles. The metal plate 64 shown in Fig. 18 contains more particles 64d than the metal plate 64 shown in Fig. 6. In the example shown in Fig. 18, some of the particles 64d are present close to each other.

[0104] After forming resist films 65a, 65b on the first surface 64a and the second surface 64b of the metal plate 64, a first surface etching step is performed in which the area of ​​the first surface 64a of the metal plate 64 that is not covered by the first resist film 65a is etched using a first etching liquid E1, as shown in FIG. 19. As a result, as shown in FIG. 19, the area of ​​the metal plate 64 that is not covered by the first resist film 65a is eroded by the first etching liquid E1. FIG. 20 is a diagram showing a state in which the erosion by the first etching liquid E1 has progressed further. In the example shown on the right side of FIG. 20, the particles 64d exposed on the wall surface fall off the metal plate 64, and a recess is formed on the wall surface of the first recess 30.

[0105] Thereafter, as shown in FIG. 21, the first recess 30 is covered with a resin 69 that is resistant to a second etching liquid used in a subsequent second surface etching step.

[0106] Next, as shown in FIG. 22, a second surface etching step is performed in which a region of the second surface 64b of the metal plate 64 that is not covered by the second resist film 65b is etched to form a second recess 35 on the second surface 64b. As a result, as shown in FIG. 22, erosion by the second etching liquid E2 progresses in the region of the metal plate 64 that is not covered by the second resist film 65b. FIG. 23 is a diagram showing a state in which erosion by the second etching liquid E2 has progressed further. In the example shown on the left side of FIG. 23, a plurality of particles 64d exposed on the wall surface have fallen off the metal plate 64. As a result, depressions corresponding to the particles 64d are formed on the wall surface of the second recess 35.

[0107] 24, the resin 69 and the resist films 65a, 65b are removed from the metal plate 64. In this manner, a plurality of through holes 25 can be formed in the metal plate 64. In the following description, a through hole 25 having a larger dimension than the standard through hole 25A due to the influence of particles in the metal plate 64 is also referred to as an enlarged through hole, and is represented by the symbol 25D or the symbol 25E.

[0108] 24, a part of through portion 42 where the opening area of ​​enlarged through hole 25D is the smallest is not formed by connecting portion 41 where first recess 30 and second recess 35 are connected, but by the outline of a recess formed in first recess 30. For this reason, dimension SD of through portion 42 of enlarged through hole 25D is larger than dimension SA of through portion 42 of standard through hole 25A.

[0109] In the example on the left side of FIG. 24, the erosion by the second etching liquid E2 progresses deeper in the portion of the second recess 35 where the recess is formed. Therefore, a part of the connection portion 41 where the first recess 30 and the second recess 35 are connected is located closer to the first surface 64a than in the case of the standard through hole 25A. As a result, the dimension SE of the through portion 42 of the enlarged through hole 25E is larger than the dimension SA of the through portion 42 of the standard through hole 25A. In the example on the left side of FIG. 24, the recess formed by the falling off of a plurality of particles 64d that were located close to each other affects the through portion 42 of the through hole 25. Therefore, the dimension SE of the through portion 42 of the enlarged through hole 25E may be larger than the dimension SD of the through portion 42 of the enlarged through hole 25D.

[0110] 25 is a plan view showing the above-mentioned multiple types of through holes 25A-25E as viewed from the first surface 64a side. The dimensions SB and SC of reduced through holes 25B and 25C are smaller than the dimension SA of standard through hole 25A. The dimension SB of reduced through hole 25B is smaller than the dimension SC of reduced through hole 25C. The dimensions SD and SE of enlarged through holes 25D and 25E are larger than the dimension SA of standard through hole 25A. The dimension SE of enlarged through hole 25E is larger than the dimension SD of enlarged through hole 25D.

[0111] Next, a case will be described in which the through-holes 25 are not formed in the metal plate 64 due to the influence of particles in the metal plate 64. In the following description of the manufacturing process of the deposition mask 20, duplicated descriptions of parts that are configured or implemented in the same manner as in the embodiment shown in Figs.

[0112] Fig. 54 is a cross-sectional view showing an example of a metal plate 64 including a plurality of particles 64d. The metal plate 64 shown in Fig. 54 includes particles having a circle-equivalent diameter of 5 µm or more. In the following description, the particles 64d having a circle-equivalent diameter of 5 µm or more may be represented by the symbol 64f. In the example shown in Fig. 55, the particles 64f are present in the bulk layer of the metal plate 64. The particles 64f may also be present in the surface layer of the metal plate 64.

[0113] As shown in Fig. 55, the area of ​​the first surface 64a that is not covered by the first resist film 65a is etched using a first etching liquid E1. The area that is not covered by the first resist film 65a is eroded by the first etching liquid E1. As a result, a first recess 30 is formed in the first surface 64a. Fig. 56 is a diagram showing a state where the erosion by the first etching liquid E1 has progressed further.

[0114] In the example shown on the left side of Fig. 56, the particles 64f are located near the first surface 64a. In this case, the flow of the first etching liquid E1 may be obstructed by the particles 64f. Therefore, as shown in Fig. 56, the first recess 30 may be smaller than that in the case of the standard through hole 25A.

[0115] 57, the first recess 30 is covered with a resin 69. The resin 69 may be in contact with the particles 64f. In this case, depressions corresponding to the particles 64f are formed on the surface of the resin 69.

[0116] 58, the area of ​​the second surface 64b that is not covered by the second resist film 65b is etched using the second etching liquid E2. The area that is not covered by the second resist film 65b is eroded by the second etching liquid E2. As a result, the second recess 35 is formed on the second surface 64b.

[0117] 58, since the first recess 30 is small, the etching of the second surface 64b may not reach the first recess 30. In other words, the second recess 35 may not be connected to the first recess 30.

[0118] In the example shown on the right side of Fig. 58, particles 64f have fallen off from the metal plate 64 and the resin 69. When the particles 64f fall off, the flow of the second etching liquid E2 may be promoted. Therefore, in the example on the right side of Fig. 58, the second recess 35 may be larger than in the case of the standard through hole 25A. In this case, the position of the connection part 41 may be located closer to the first surface 64a than in the case of the standard through hole 25A.

[0119] Next, as shown in Fig. 59, resin 69 and resist films 65a, 65b are removed from metal plate 64. In the example shown on the left side of Fig. 58, second recess 35 is not connected to first recess 30, so there is no through hole 25. In the following description, the portion where first recess 30 and second recess 35 are not connected is also referred to as a non-through portion.

[0120] In the example shown on the right side of Fig. 59, through-hole 42 is configured with connecting portion 41. The position of connecting portion 41 is located closer to first surface 64a than in the case of standard through-hole 25A. Therefore, dimension SF of through-hole 25F is larger than dimension SA of standard through-hole 25A. That is, through-hole 25F in the example shown on the right side of Fig. 59 is an enlarged through-hole.

[0121] As described above, when the metal plate 64 contains particles having a circle equivalent diameter of 5 μm or more, non-penetrating portions or enlarged through holes may occur. Although not shown, reduced through holes may also occur, as in the example on the right side of FIG. Particles having an equivalent circle diameter of 5 μm or more can cause various defects. Therefore, the probability that one particle having an equivalent circle diameter of 5 μm or more causes a defective deposition mask is higher than the probability that one particle having an equivalent circle diameter of 3 μm or more causes a defective deposition mask.

[0122] The particles 64d, 64e, and 64f contained in the metal plate 64 may adversely affect the accuracy of the shape of the through-hole 25 of the deposition mask 20. The decrease in the dimensional accuracy of the through-hole 25 may be particularly noticeable when the thickness of the metal plate 64 is small. This is because the ratio of the dimensions of the particles 64d, 64e, and 64f to the thickness of the metal plate 64 is large.

[0123] In order to solve such problems, this embodiment proposes to use a metal plate 64 that satisfies the following conditions (1) and (2): A sample is taken out from the metal plate 64. (1) Sample volume 1 mm 3 The number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 50 to 3,000. (2) Sample volume 1 mm 3 The number of particles having an equivalent circle diameter of 3 μm or more contained per unit area is 50 or less.

[0124] As shown in the above-mentioned Figs. 18 to 24, when the number of particles 64d contained in the metal plate 64 increases, depressions due to the falling off of the particles 64d are likely to be formed on the wall surface of the first recess 30 and / or the wall surface of the second recess 35. As a result, the dimensions of the through hole 25 are likely to deviate from the design values. For example, enlarged through holes 25D, 25E ​​having dimensions larger than the standard through hole 25A are likely to be formed. In contrast, when the volume of the sample is 1 mm as in the above-mentioned condition (1), 3By setting the upper limit of the number of particles having a circle equivalent diameter of 1 μm or more per hole to 3000, it is possible to prevent the size of through hole 25 from deviating from the design value, as supported by the examples described later. In particular, it is possible to prevent the size of through hole 25 from becoming larger than the design value.

[0125] On the other hand, the particles exposed on the surface of the metal plate 64 may contribute to improving the adhesion between the resist films 65a and 65b and the metal plate 64, as described above. For this reason, as in the above-mentioned condition (1), 3 By setting the lower limit of the number of particles having a circular equivalent diameter of 1 μm or more per particle to 50, it is possible to prevent the resist films 65a, 65b of the resist patterns 65c, 65d from peeling off from the metal plate 64 during the manufacturing process of the deposition mask 20, such as the etching process.

[0126] As the pixel density of the display device increases, the arrangement period of the through holes 25 of the deposition mask 20 becomes shorter, and the dimensions of the resist films 65a, 65b of the resist patterns 65c, 65d, such as the width, become smaller. On the other hand, the resist films 65a, 65b have smaller dimensions, such as the width, and therefore, the smaller the area of ​​the resist films 65a, 65b, the more likely they are to peel off from the metal plate 64 during the manufacturing process of the deposition mask 20. According to this embodiment, the adhesion between the resist films 65a, 65b and the metal plate 64 can be improved, making it easier to adopt the resist films 65a, 65b with smaller dimensions. As a result, the arrangement period of the through holes 25 of the deposition mask 20 can be made shorter, and a display device having a high pixel density can be manufactured.

[0127] As shown in the above-mentioned Figs. 12 to 17, when the size of the particles 64e contained in the metal plate 64 becomes large, it is considered that the first recess 30 formed in the first surface 64a by the first surface etching process reaches the second surface 64b, or the resin 69 provided in the first recess 30 reaches the vicinity of the second surface 64b. In this case, the second surface etching process performed from the second surface 64b side may be hindered by the resin 69. This makes it easier to form reduced through holes 25B, 25C having dimensions smaller than the standard through hole 25A, for example. In contrast, as in the above-mentioned condition (2), when the volume of the sample is 1 mm 3 By setting the upper limit of the number of particles having a circle equivalent diameter of 3 μm or more per hole to 50, it is possible to prevent the size of through hole 25 from deviating from the design value, as supported by the examples described later. In particular, it is possible to prevent the size of through hole 25 from becoming smaller than the design value.

[0128] As described above, the adverse effects caused by the particles 64d and 64e are more likely to occur as the thickness of the metal plate 64 becomes thinner. Here, by using the embodiment of the present disclosure, as supported by the examples, it becomes possible to manufacture the deposition mask 20 having the through-holes 25 with the desired dimensional accuracy, even when using a relatively thin metal plate 64 having a thickness of 30 μm or less or 20 μm or less.

[0129] The metal plate 64 may be one that satisfies the following condition (3). (3) Sample volume 1 mm 3 The number of particles having an equivalent circle diameter of 1 μm or more contained per unit area is 1,000 or less. By the metal plate 64 satisfying the condition (3), it is possible to prevent the plurality of particles 64d from being close to each other in the metal plate 64. This makes it possible to prevent the plurality of particles 64d from falling off the wall surface of one first recess 30 or the wall surface of one second recess 35. This makes it possible to prevent a depression with a larger volume, for example a depression corresponding to the volume of the plurality of particles 64d, from being formed on the wall surface of the first recess 30 or the wall surface of the second recess 35. This makes it possible to prevent the dimensions of the through hole 25 from deviating from the design value. In particular, it is possible to prevent the dimensions of the through hole 25 from becoming larger than the design value.

[0130] Under conditions (1) and (3), the sample volume was 1 mm 3 The above describes examples of the upper and lower limits of the number of particles having a circular equivalent diameter of 1 μm or more per 1 mm of sample volume, but other upper and lower limits may also be used. 3 The number of particles having a circular equivalent diameter of 1 μm or more contained per mm of sample may be, for example, 50 or more, 100 or more, 200 or more, or 300 or more. 3 The number of particles having an equivalent circle diameter of 1 μm or more contained per unit area may be, for example, 3000 or less, 2000 or less, 1000 or less, or 500 or less.

[0131] Sample volume 1mm 3 The number of particles having a circular equivalent diameter of 1 μm or more contained per mm of sample may be, for example, 50 or more, 100 or more, 200 or more, or 300 or more. 3 The number of particles having a circular equivalent diameter of 1 μm or more contained per mm of the sample may be, for example, 500 or less, 1000 or less, 2000 or less, or 3000 or less. 3The range of the number of particles having an equivalent circle diameter of 1 μm or more contained per mm of sample volume may be defined by a first group consisting of 50, 100, 200 and 300, and / or a second group consisting of 500, 1000, 2000 and 3000. 3 The range of the number of particles having an equivalent circular diameter of 1 μm or more per mm of sample volume may be defined by a combination of any one of the values ​​in the first group described above with any one of the values ​​in the second group described above. 3 The range of the number of particles having a circular equivalent diameter of 1 μm or more per 1 mm of sample volume may be determined by a combination of any two of the values ​​in the first group described above. 3The range of the number of particles having a circle equivalent diameter of 1 μm or more per unit area may be determined by a combination of any two of the values ​​included in the second group described above. For example, it may be 50 to 3000, 50 to 2000, 50 to 1000, 50 to 500, 50 to 300, 50 to 200, 50 to 100, 100 to 3000, 100 to 2000, 100 to 1000, 100 to 500, 100 to 300, 100 to 200, 200 to 3000, 200 to 3000, 200 to 3000, 200 to 4000, 200 to 500, 200 to 4000, 200 to 500, 200 to 500, 200 to 3000, 200 to 200, 200 to 3000, 200 to 3000, 200 to 3000, 200 to 4 ... It may be at least 2000 or less, it may be 200 or more and 1000 or less, it may be 200 or more and 500 or less, it may be 200 or more and 300 or less, it may be 300 or more and 3000 or less, it may be 300 or more and 2000 or less, it may be 300 or more and 1000 or less, it may be 300 or more and 500 or less, it may be 500 or more and 3000 or less, it may be 500 or more and 2000 or less, it may be 500 or more and 1000 or less, it may be 1000 or more and 3000 or less, it may be 1000 or more and 2000 or less, it may be 2000 or more and 3000 or less.

[0132] The metal plate 64 may be one that satisfies the following condition (4). (4) Sample volume 1 mm 3 The number of particles having an equivalent circle diameter of 3 μm or more contained per unit area is 20 or less. By making the metal plate 64 satisfy the condition (4), it is possible to further prevent the first recess 30 formed in the first surface 64a by the first surface etching step from reaching the second surface 64b, and to further prevent the resin 69 provided in the first recess 30 from reaching the vicinity of the second surface 64b. This makes it possible to prevent the second surface etching step performed from the second surface 64b side from being hindered by the resin 69. This makes it possible to further prevent the reduced through holes 25B and 25C from being formed.

[0133] Under conditions (2) and (4), the sample volume was 1 mm 3 Although the above is an example of the upper limit value for the number of particles having a circular equivalent diameter of 3 μm or more contained per 1 mm of sample volume, other upper limit values ​​can also be used. 3 The number of particles having an equivalent circle diameter of 3 μm or more contained per unit area may be, for example, 50 or less, 40 or less, 30 or less, 20 or less, 15 or less, 10 or less, or 5 or less.

[0134] The metal plate 64 may be one that satisfies the following condition (5). (5) Sample volume 1 mm 3 The number of particles having an equivalent circle diameter of 5 μm or more contained per unit area is 20 or less. When the metal plate 64 satisfies the condition (5), for example, it is possible to prevent the flow of the etching solution from being blocked by particles, thereby preventing the occurrence of non-penetrating portions.

[0135] Sample volume 1mm 3 The number of particles having an equivalent circle diameter of 5 μm or more contained per unit area may be, for example, 15 or less, 10 or less, 5 or less, or 2 or less. For example, the metal plate 64 may be one that satisfies the following condition (6). (6) Sample volume 1 mm 3The number of particles having an equivalent circle diameter of 5 μm or more contained per unit area is 2 or less.

[0136] The metal plate 64 may be one that satisfies the following condition (7). (7) Sample volume 1 mm 3 The number of particles with an equivalent circle diameter of 10 μm or more contained per unit area is zero. The probability that one particle having a circle equivalent diameter of 10 μm or more causes a defective deposition mask is higher than the probability that one particle having a circle equivalent diameter of 5 μm or more causes a defective deposition mask. When the metal plate 64 satisfies the condition (7), the probability of defective products can be reduced.

[0137] The above conditions (1) to (7) may represent the configuration of the metal plate 64 after it has been processed into a deposition mask. Alternatively, the above conditions (1) to (7) may represent the configuration of the metal plate 64 before it is processed into a deposition mask. The metal plate 64 includes a sampling portion from which a sample satisfying one or more of the above conditions (1) to (7) can be extracted. The sampling portion includes a first surface 64a and a second surface 64b of the metal plate 64. That is, the sampling portion extends in the thickness direction of the metal plate 64 from the first surface 64a to the second surface 64b.

[0138] In the present embodiment, one of the problems to be solved is to suppress the adverse effect of particles present in the bulk layer of the metal plate 64 on the accuracy of the shape of the through-hole 25 of the deposition mask 20. In order to solve such a problem, it is required to appropriately measure the number and dimensions of particles present in the entire area in the thickness direction of the metal plate 64, including the bulk layer. Hereinafter, a method for measuring particles present in the metal plate 64 will be described.

[0139] First, a first sampling step is performed to extract a sample having a predetermined volume from the base material or metal plate 64. For example, as shown in FIG. 26, the metal plate 64 unwound from the roll is cut in the thickness direction of the metal plate 64 to obtain a sample 81 having a square shape in a plan view. The length K1 of one side of the square sample 81 is, for example, 60 mm. The sample 81 includes the first surface 64a and the second surface 64b of the metal plate 64. Thus, the sample 81 includes the above-mentioned surface layer and bulk layer of the metal plate 64. For example, scissors may be used as a tool for cutting out the sample 81 from the metal plate 64.

[0140] Next, a second sampling step is performed in which sample pieces 81a are cut out from the sample 81. For example, as shown in FIG. 27, a plurality of sample pieces 81a, for example three, are obtained by punching the sample 81. For example, the sample piece 81a has a circular shape with a diameter K2 in a plan view. The diameter K2 is, for example, 20 mm. The sample piece 81a includes the first surface 64a and the second surface 64b of the metal plate 64. Therefore, the sample piece 81a includes the above-mentioned surface layer and bulk layer of the metal plate 64. As a tool for reproducibly and accurately cutting out the sample pieces 81a from the sample 81, for example, a punching device may be used.

[0141] Next, a sample washing step is performed to wash the sample piece 81a. This makes it possible to remove foreign matter that has adhered to the sample piece 81a due to the first and second sampling steps. As a washing method, ultrasonic washing can be used in which ultrasonic waves are applied to pure water while the sample piece 81a is immersed in the pure water.

[0142] Next, a particle extraction step is performed to extract particles from the sample 81. For example, first, a sample dissolving step is performed to dissolve the sample pieces 81a taken out from the sample 81 in an aqueous solution. For example, as shown in FIG. 28, three sample pieces 81a are put into a container 82 containing 100 ml of an aqueous solution 83, and the sample pieces 81a are dissolved in the aqueous solution 83. As the aqueous solution 83, a solution that easily dissolves iron alloys but does not easily dissolve particles is used. For example, 100 ml of an aqueous solution containing nitric acid is used as the aqueous solution 83. This allows the particles contained in the sample that are poorly soluble in nitric acid to be separated from the iron alloy. The temperature of the aqueous solution 83 is, for example, 50° C. The aqueous solution 83 is prepared by mixing, for example, a stock solution containing nitric acid at a concentration of 60% by weight with pure water having the same volume as the stock solution.

[0143] The sample dissolving step may take, for example, 30 minutes. The first 15 minutes may be performed while the aqueous solution 83 is being shaken by hand, and the next 15 minutes may be performed while the aqueous solution 83 is left standing. The sample dissolving step may take 30 minutes or more.

[0144] Next, a filtration step is performed in which particles are extracted from the aqueous solution 83 in which the sample pieces 81a are dissolved, using a suction filtration device. The suction filtration device has filter paper and a pressure reducing section that reduces the pressure in the space downstream of the filter paper. The filter paper is made of a material that is resistant to acid, such as Teflon. The filter paper is configured to at least not allow particles of 1 μm or more to pass through. For example, the roughness of the filter paper, i.e., the pore size, is 0.45 μm. Therefore, as shown in FIG. 29, particles 64d and 64e having a size of at least 1 μm or more remain on the filter paper 84.

[0145] In the filtering step, first, an aqueous solution 83 in which sample pieces 81a are dissolved is poured from a container 82 onto the filter paper 84 through a cylindrical member placed on the filter paper 84. Then, a rinsing step for rinsing the container 82 is carried out three times. In the rinsing step, first, 100 ml of pure water is poured into the emptied container 82, and then the pure water is poured from the container 82 onto the filter paper 84 through the cylindrical member. Then, a pressure reducing unit such as a pump is used to reduce the pressure in the space downstream of the filter paper.

[0146] Next, a particle drying step is performed to dry the particles 64d, 64e on the filter paper 84. Specifically, after removing the above-mentioned cylindrical member from the filter paper 84, the filter paper 84 is covered from above with a wrap film, and the space below the filter paper is continuously depressurized using a pressure reducing unit such as a pump. By placing a cover such as a wrap film above the filter paper 84 so as not to come into contact with the filter paper 84, it is possible to prevent foreign matter in the ambient atmosphere from adhering to the filter paper 84 while the particles 64d, 64e on the filter paper 84 are dried. The time for the particle drying step is not particularly limited, but is, for example, 4 hours or more and 6 hours or less.

[0147] Next, a preparation step is performed for observing the particles 64d, 64e on the filter paper 84 with a scanning electron microscope (hereinafter also referred to as SEM). First, the peripheral portion of the filter paper 84 is fixed to a pedestal with carbon tape or the like. Next, in order to ensure conductivity during observation with the SEM, a platinum film is formed on the filter paper 84 by sputtering. The sputtering time is, for example, 10 seconds. Next, a jig is attached to the pedestal as necessary, and then the pedestal is attached to the SEM.

[0148] Next, an observation step is performed to observe the particles 64d on the filter paper 84 using an SEM. In the observation step, first, an observation condition adjustment step is performed to adjust the observation conditions of the SEM. An identification condition adjustment step is performed to adjust the identification conditions for identifying the particles 64d from the image obtained by the SEM. An observation range setting step is performed to set the observation range of the filter paper 84.

[0149] The SEM may be a JSM7800FPRIME manufactured by JEOL Ltd. The settings of the SEM are as follows: Detector: Backscattered electron detector LVBED-C Observation magnification: 1000x Acceleration voltage: 15 kV Working distance: 10mm Irradiation current: 15

[0150] The observation condition adjustment step will be described with reference to FIG. 30 and FIG. 31. In the observation condition adjustment step, the contrast and / or brightness of the SEM is adjusted so that the particles 64d stand out more than the fibers of the filter paper 84. FIG. 30 is an example of an SEM image obtained before the contrast and / or brightness of the SEM is adjusted. FIG. 31 is an example of an SEM image obtained after the contrast and / or brightness of the SEM is adjusted. In the observation condition adjustment step, while checking the SEM image, the contrast of the SEM is adjusted to an appropriate value within the range of 3000 to 4000, and the brightness of the SEM is adjusted to an appropriate value within the range of 200 to 400. At this time, the contrast and / or brightness of the SEM is adjusted to an extent that part of the fibers of the filter paper 84 is also visible. This makes it possible to prevent part of the particles 64d from disappearing from the image.

[0151] The identification condition adjustment step will be described with reference to Fig. 32 and Fig. 33. As an analysis means for identifying particles from an image obtained by SEM, automatic particle analysis software Particle Phaze Analysis version 6.53 attached to an energy dispersive X-ray spectrometer (hereinafter also referred to as an EDX device) may be used. As the EDX device, an Octane Elect EDX device manufactured by Ametech Co., Ltd. may be used.

[0152] In the identification condition adjustment step, particles 64d in the SEM image are identified using particle analysis software. Specifically, the brightness threshold in the automatic particle analysis software is adjusted. Then, the automatic particle analysis software recognizes an object in the image that has a brightness equal to or greater than the threshold and a maximum dimension of 0.8 μm or greater as a particle 64d.

[0153] Fig. 32 is an example of an image before the brightness threshold of the automatic particle analysis software is adjusted. Fig. 33 is an example of an image after the brightness threshold of the automatic particle analysis software is adjusted. The brightness threshold of the automatic particle analysis software can be adjusted within a range of 0 to 255. In the identification condition adjustment step, the brightness threshold of the automatic particle analysis software is adjusted to, for example, 120 while checking the image. At this time, the contrast and / or brightness of the SEM is adjusted to such an extent that part of the fibers of the filter paper 84 can be visually recognized. This makes it possible to prevent part of the multiple particles 64d from disappearing from the image.

[0154] The observation range setting step will be described with reference to FIG. 34. In FIG. 34, a frame with a reference symbol 85 indicates an area of ​​an image 85 that can be acquired in one observation using an SEM. In the observation range setting step, as shown in FIG. 34, an observation range 86 is set so as to acquire 15 images 85 arranged in a first observation direction A1 and acquire 10 images 85 arranged in a second observation direction A2 perpendicular to the first observation direction A1. The observation range 86 composed of a plurality of images 85 may or may not include the center part of the filter paper 84 as shown in FIG. 34. In the example shown in FIG. 34, the number of images 85 acquired for one filter paper 84 is 150. Images 85 may be acquired in two or more observation ranges 86 for one filter paper 84. For example, 150 images 85 may be acquired in an observation range 86 including the center part of the filter paper 84, and 150 images 85 may be acquired in an observation range 86 including an edge part of the filter paper 84. This makes it possible to confirm whether or not there is a difference in the number of particles 64d detected between the center portion of the filter paper 84 and the edge portion of the filter paper 84.

[0155] The settings of the automatic particle analysis software are as follows: Number of pixels in image: 1024 (first observation direction A1) x 800 (second observation direction A2) Time constant: 1.92μs Preset (analysis time per particle): 1 second Scan Mode: Core 50% Handling particles on image boundaries: Recognize them as particles The dimension K4 of the image 85 in the first observation direction A1 on the filter paper 84 is 114 μm, and the dimension K5 of the image 85 in the second observation direction A2 on the filter paper 84 is 89 μm.

[0156] As shown in FIG. 34, a gap is provided between two adjacent images 85 in the first observation direction A1. A dimension K6 of the gap between two adjacent images 85 in the first observation direction A1 is 1 / 10 of the dimension K4. Similarly, a gap is provided between two adjacent images 85 in the second observation direction A2. A dimension K7 of the gap between two adjacent images 85 in the second observation direction A2 is 1 / 10 of the dimension K5. This makes it possible to prevent one particle 64d from being detected in multiple images 85 in a duplicated manner.

[0157] After carrying out the above-mentioned observation condition adjustment process, identification condition adjustment process, and observation range setting process, the observation range 86 on the filter paper 84 is observed using an SEM, whereby particles 64d located in the observation range 86 and having a maximum dimension of 0.8 μm or more can be detected.

[0158] Next, an analysis step is performed to analyze the detected particles 64d. Specifically, a composition analysis step is performed to analyze the main components of the particles 64d. A diameter calculation step is performed to calculate the circle-equivalent diameters of the particles 64d. An extraction step is performed to extract particles 64d that contain a predetermined component and have a circle-equivalent diameter of 1 μm or more based on the results of the analysis step and the composition analysis step.

[0159] The composition analysis step will be described with reference to FIG. 35. In the composition analysis step, as shown in FIG. 35, composition analysis is performed at a plurality of analysis points 87 in the particle 64d using energy dispersive X-ray spectroscopy (hereinafter also referred to as EDX method). The composition analysis is performed on all the detected particles 64d. As an EDX device for performing the EDX method, the above-mentioned Octane Elect EDX device manufactured by Ametech Co., Ltd. may be used. It is possible to simultaneously perform composition analysis at a plurality of analysis points 87 in one particle 64d. When the above-mentioned scan mode is set to "core 50%", the plurality of analysis points 87 are determined to be distributed over 50% of the area of ​​one particle 64d. When the above-mentioned preset is set to "1 second", the time required for composition analysis of one particle 64d is 1 second. The average value of the data of the composition analysis at the plurality of analysis points 87 is adopted as the data of the composition of one particle 64d. By performing the composition analysis, information on the main component and other components constituting the particle 64d can be obtained.

[0160] The diameter calculation step will be described with reference to Fig. 35. A particle 64d shown in Fig. 35 is an aggregate of pixels having a brightness equal to or greater than the above-mentioned threshold, for example, equal to or greater than 120. In the diameter calculation step, first, the number of pixels Pn in which the particle 64d appears is calculated. Next, the area Ds of the particle 64d in plan view is calculated by multiplying the number of pixels Pn by the area Ps of the pixel. Ds = Pn × Ps Next, assuming that the particle 64d has a perfect circular shape in a plan view, the diameter of the particle 64d is calculated from the area Ds of the particle 64d. The diameter calculated in this manner is the circle-equivalent diameter Da1 of the particle 64d. Da1 = 2 × (Ds / π) 0.5 The calculation of the circle equivalent diameter is performed for all detected particles 64d.

[0161] In the diameter calculation process, one particle 64d may be erroneously recognized as two or more particles 64d, and the circle equivalent diameter Da1 may be calculated. It is preferable for a person to check whether such erroneous data exists. If erroneous data exists, it is preferable for a person to manually calculate the circle equivalent diameter Da1 and analyze the composition of the erroneously recognized particle 64d. For example, all components at multiple analysis points 87 in the composition analysis results analyzed as two or more particles 64d are added together, and then the total weight percentage of each component is manually corrected to be 100.

[0162] The extraction process will be described. In the extraction process, first, a first exclusion process is carried out to exclude particles 64d having a carbon and fluorine content of 80% by weight or more from among the detected particles 64d. This makes it possible to prevent objects resulting from the filter paper 84 from being recognized as particles 64d. "Exclusion" means excluding from the target when determining whether the above conditions (1) and (2) are satisfied.

[0163] Next, a second exclusion process is performed to exclude particles 64d having an iron content of 10% by weight or more from among the multiple particles 64d that were not excluded by the first exclusion process. Next, a third exclusion process is performed to exclude particles 64d having an iron content greater than the total content of aluminum, magnesium, silicon, phosphorus, sulfur, chromium, and zirconium from among the multiple particles 64d that were not excluded by the first and second exclusion processes. Next, a fourth exclusion process is performed to exclude particles 64d having a circle equivalent diameter of less than 1 μm from among the multiple particles 64d that were not excluded by the first, second, and third exclusion processes. Then, information such as the number, circle equivalent diameter, and components of the particles 64d that were not excluded is organized.

[0164] If there are 100 or more particles 64d with an iron content of 10% by weight or more, or if the ratio of the number of particles 64d with an iron content of 10% by weight or more to the total number of particles 64d is 50% or more, it is expected that the sample was not sufficiently dissolved in the above-mentioned sample dissolution step. In this case, it is preferable to repeat the method of measuring the particles present in the metal plate 64 from the above-mentioned first sampling step.

[0165] Next, based on the information on the number Z1 of particles 64d having a circle equivalent diameter of 1 μm or more obtained in the extraction step, 3 A conversion step is performed to calculate the number Z2 of particles 64d contained per 1 mm 3 The number Z2 of particles 64d having an equivalent circle diameter of 1 μm or more contained per unit area is calculated based on the following formula (1). Z2 = Z1 × (effective area of ​​filter paper 84 / area of ​​SEM observation range) × (1 / dissolution volume) Effective area of ​​filter paper 84 = (R / 2) 2 ×π Area of ​​SEM observation range = area of ​​image 85 × number of images 85 Dissolution volume = (K2 / 2) 2 ×π × thickness of metal plate 64 × number of sample pieces 81a

[0166] R is the diameter of the tubular member placed on the filter paper 84 during the filtration process. When R is 15 mm, the effective area of ​​the filter paper 84 is 176.715 mm 2 It is. When the dimension K4 of the image 85 in the first observation direction A1 is 114 μm, the dimension K5 of the image 85 in the second observation direction A2 is 89 μm, and the number of images 85 in the observation range 86 of the SEM is 150, the area of ​​the observation range of the SEM is 1.5219 mm 2 It is. When the thickness of the metal plate 64 is 20 μm, the diameter K2 of the sample piece 81 a is 20 mm, and the number of the sample pieces 81 a is three, the melting volume is 18.850 mm 3 It is.

[0167] In this way, for particles 64d having a circle equivalent diameter of 1 μm or more, the volume of sample 81 was 1 mm 3 Information such as the number Z2 of particles 64d contained per unit area, their circle equivalent diameter, and their composition can be obtained.

[0168] Particles 64d having a circle-equivalent diameter of 1 μm or more may be circular in plan view. "Particles 64d are circular" means that the aspect of particles 64d is 2.5 or less. The aspect of particles 64d is calculated by the following formula. Aspect = π × (LP / 2) 2 / Ds LP is the longest diameter of the particle 64d, and is also called the longest projection. Ds is the area of ​​the particle 64d, as described above. The aspect, the longest projection LP, and the area Ds are all calculated by analyzing the particle 64d using the automatic particle analysis software Particle Phaze Analysis version 6.53 manufactured by AMETECH.

[0169] In the following description, the ratio of the number of particles 64d having an aspect ratio of 2.5 or less to the total number of particles 64d having a circle-equivalent diameter of 1 μm or more is also referred to as the circularity ratio. The circularity ratio may be, for example, 70% or more, 80% or more, 90% or more, or 95% or more.

[0170] Next, a method for manufacturing a metal plate 64 that satisfies at least the above-mentioned conditions (1) and (2) 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 total content of nickel and cobalt in the rolled material is 30 mass% or more and 38 mass% or less.

[0171] First, a preparation step is carried out to prepare a base material having an iron alloy containing at least nickel. In this embodiment, the base material is a member that will become the above-mentioned metal plate 64 by rolling. The preparation step includes at least a first melting step.

[0172] First, iron, nickel and other raw materials are prepared. For example, each raw material is prepared so that the ratio of iron and the ratio of nickel to the whole raw materials are about 64% by weight and about 36% by weight, respectively. Next, each raw material is crushed as necessary, and then a first melting process is performed in which each raw material is melted in a melting furnace. The first melting process includes, for example, vacuum melting. Vacuum melting is a method of obtaining molten metal by melting raw materials in a vacuum atmosphere. For example, the raw materials may be melted in a vacuum atmosphere by utilizing a gas discharge such as an arc discharge. The raw materials may be melted in an induction furnace installed in a vacuum atmosphere. The vacuum atmosphere is, for example, 1 Pa or less, and may be 0.1 Pa or less. Thereafter, the molten metal is solidified to obtain a first ingot.

[0173] The melting temperature is set according to the raw material, and is, for example, 1500°C or higher. The first melting step may include a step of feeding additives such as aluminum, manganese, and silicon into the melting furnace. The additives may realize functions such as deoxidization, dehydration, and denitrification. The melting step may be performed under an atmosphere of an inert gas such as argon gas at a low pressure state lower than atmospheric pressure. The additives form compounds by reacting with oxygen, etc. Such compounds may constitute the above-mentioned particles. Therefore, by adjusting the amount of the additives, the amount or size of the particles contained in the metal plate can be adjusted. For example, by reducing the amount of the additives, the amount of the particles contained in the metal plate can be reduced. Alternatively, by reducing the amount of the additives, the circle equivalent diameter of the particles contained in the metal plate can be reduced.

[0174] Fig. 36 is an enlarged cross-sectional view of the surface and its periphery of the first ingot 64i removed from the melting furnace. As shown in Fig. 36, particles 64d containing additives such as aluminum are likely to be present on the surface and its periphery of the first ingot 64i. This is thought to be because the specific gravity of the particles 64d is smaller than the specific gravity of the molten metal. However, the reason why the particles 64d are likely to be present on the surface and its periphery is not limited to the above reason.

[0175] The duration of the first dissolution step is preferably set to allow the particles 64d to migrate to or around the surface.

[0176] In order to remove the particles 64d, a first surface treatment step may be performed after the first melting step, in which a surface portion 64s of the first ingot 64i is removed as shown in FIG. 37. Reference symbol X1 indicates the thickness of the surface portion 64s to be removed. By removing the surface portion 64s, the number and density of the particles 64d contained in the metal plate 64 can be reduced. In addition, oxide coatings such as scale can be removed. As will be described later, the number and density of the particles 64d contained in the metal plate 64 can also be reduced by the metal plate surface treatment step of removing the surface portion 64u of the metal plate 64.

[0177] The thickness X2 of the first ingot 64i before the surface portion 64s is removed may be, for example, 100 mm or more, 150 mm or more, or 200 mm or more. The thickness X2 may be, for example, 300 mm or less, 400 mm or less, or 500 mm or less. The range of the thickness X2 may be determined by a first group consisting of 100 mm, 150 mm, and 200 mm, and / or a second group consisting of 300 mm, 400 mm, and 500 mm. The range of the thickness X2 may be determined by a combination of any one of the values ​​included in the above-mentioned first group and any one of the values ​​included in the above-mentioned second group. The range of the thickness X2 may be determined by a combination of any two of the values ​​included in the above-mentioned first group. The range of the thickness X2 may be determined by a combination of any two of the values ​​included in the above-mentioned second group. For example, it may be 100 mm or more and 500 mm or less, 100 mm or more and 400 mm or less, 100 mm or more and 300 mm or less, 100 mm or more and 200 mm or less, 100 mm or more and 150 mm or more and 150 mm or more and 500 mm or less, 150 mm or more and 400 mm or less, 150 mm or more and 300 mm or less, 150 mm or more and 200 mm or less, 200 mm or more and 500 mm or less, 200 mm or more and 400 mm or less, 200 mm or more and 300 mm or less, 300 mm or more and 500 mm or less, 300 mm or more and 400 mm or less, or 400 mm or more and 500 mm or less.

[0178] The thickness X1 of the surface portion 64s to be removed may be, for example, 5 mm or more, 10 mm or more, 12 mm or more, or 15 mm or more. The thickness X1 may be, for example, 20 mm or less, 25 mm or less, 30 mm or less, or 40 mm or less. The range of the thickness X1 may be determined by a first group consisting of 5 mm, 10 mm, 12 mm, and 15 mm, and / or a second group consisting of 20 mm, 25 mm, 30 mm, and 40 mm. The range of the thickness X1 may be determined by a combination of any one of the values ​​included in the above-mentioned first group and any one of the values ​​included in the above-mentioned second group. The range of the thickness X1 may be determined by a combination of any two of the values ​​included in the above-mentioned first group. The range of the thickness X1 may be determined by a combination of any two of the values ​​included in the above-mentioned second group. For example, it may be 5 mm or more and 40 mm or less, 5 mm or more and 30 mm or less, 5 mm or more and 25 mm or less, 5 mm or more and 20 mm or less, 5 mm or more and 15 mm or less, 5 mm or more and 12 mm or less, 5 mm or more and 10 mm or more and 10 mm or more and 10 mm or more and 40 mm or less, 10 mm or more and 30 mm or more and 10 mm or more and 25 mm or less, 10 mm or more and 20 mm or less, 10 mm or more and 15 mm or less, 10 mm or more and 12 mm or less, 12 mm or more and 40 mm or less, 1 It may be 2mm or more and 30mm or less, 12mm or more and 25mm or less, 12mm or more and 20mm or less, 12mm or more and 15mm or less, 15mm or more and 40mm or less, 15mm or more and 30mm or less, 15mm or more and 25mm or less, 15mm or more and 20mm or less, 20mm or more and 40mm or less, 20mm or more and 30mm or less, 20mm or more and 25mm or less, 25mm or more and 40mm or less, 25mm or more and 30mm or less, 30mm or more and 40mm or less.

[0179] By making the thickness X1 5 mm or more, it is possible to reduce the number and density of the particles 64d contained in the metal plate 64. The larger the range X1, the smaller the number of the particles 64d. On the other hand, the larger the range X1, the smaller the amount of the obtained metal plate 64. By making the range X1 40 mm or less, it is possible to suppress an increase in the manufacturing cost of the metal plate 64.

[0180] The thickness X1 of the surface portion 64s may be determined based on a ratio to the thickness X2 of the first ingot 64i before the surface portion 64s is removed. X1 / X2 may be, for example, 0.01 or more, 0.02 or more, 0.03 or more, or 0.05 or more. X1 / X2 may be, for example, 0.10 or less, 0.15 or less, 0.20 or less, or 0.30 or less. The range of X1 / X2 may be determined by a first group consisting of 0.01, 0.02, 0.03, and 0.05, and / or a second group consisting of 0.10, 0.15, 0.20, and 0.30. The range of X1 / X2 may be determined by a combination of any one of the values ​​included in the first group described above and any one of the values ​​included in the second group described above. The range of X1 / X2 may be determined by a combination of any two of the values ​​included in the first group described above. The range of X1 / X2 may be determined by a combination of any two of the values ​​included in the second group described above. For example, it may be 0.01 or more and 0.30 or less, 0.01 or more and 0.20 or less, 0.01 or more and 0.15 or less, 0.01 or more and 0.10 or less, 0.01 or more and 0.05 or less, 0.01 or more and 0.03 or less, 0.01 or more and 0.02 or less, 0.02 or more and 0.30 or less, 0.02 or more and 0.20 or less, 0.02 or more and 0.15 or less, 0.02 or more and 0.10 or less, 0.02 or more and 0.05 or less, 0.02 or more and 0.03 or less, or 0.03 or more and 0.30 or less. Alternatively, the range may be 0.03 or more and 0.20 or less, 0.03 or more and 0.15 or less, 0.03 or more and 0.10 or less, 0.03 or more and 0.05 or less, 0.05 or more and 0.30 or less, 0.05 or more and 0.20 or less, 0.05 or more and 0.15 or less, 0.05 or more and 0.10 or less, 0.10 or more and 0.30 or less, 0.10 or more and 0.20 or less, 0.10 or more and 0.15 or less, 0.15 or more and 0.30 or less, 0.15 or more and 0.20 or less, or 0.20 or more and 0.30 or less.

[0181] Particles 64d having a large equivalent circle diameter may be more likely to exist near the surface of the metal plate 64 than particles 64d having a small equivalent circle diameter. The reason for this is thought to be that the larger the equivalent circle diameter of the particles 64d, the faster the upward movement speed of the particles 64d during the dissolving process. However, the reason why particles 64d having a large equivalent circle diameter are more likely to exist on the surface is not limited to the above reason.

[0182] When particles 64d having a large equivalent circle diameter are likely to be present on the surface, the process of removing the surface portion 64s can particularly contribute to reducing the number and density of particles 64d having a large equivalent circle diameter. Therefore, by adjusting the thickness X1 of the surface portion 64s, it may be possible to adjust the first ratio, second ratio, and third ratio of the particles 64d contained in the metal plate 64. Similarly, by adjusting the thickness X3 of the surface portion 64u, which will be described later, it may be possible to adjust the first ratio, second ratio, and third ratio of the particles 64d contained in the metal plate 64. The first ratio is the ratio of the first quantity to the total quantity of particles having an equivalent circle diameter of 1 μm or more. The first quantity is the ratio of the first quantity to the total quantity of particles having an equivalent circle diameter of 1 mm 3 The second ratio is the number of particles having a circle-equivalent diameter of 1 μm or more and less than 3 μm contained per 1 mm of volume of sample 81. The second ratio is the ratio of the second number to the total number of particles having a circle-equivalent diameter of 1 μm or more. The second number is the number of particles having a circle-equivalent diameter of 1 μm or more contained per 1 mm of volume of sample 81. 3 The third ratio is the number of particles having a circle-equivalent diameter of 3 μm or more and less than 5 μm contained per unit volume of sample 81. The third ratio is the ratio of the third number to the total number of particles having a circle-equivalent diameter of 1 μm or more. The third number is the number of particles having a circle-equivalent diameter of 1 μm or more contained per unit volume of sample 81. 3 The total number is the number of particles with a circular equivalent diameter of 5 μm or more per 1 mm of the volume of sample 81. 3 The second ratio and the third ratio can be reduced by the step of removing the surface portions 64s and 64u.

[0183] On the other hand, as shown in the examples described later, the second ratio and the third ratio of the metal plates showing a small total quantity, for example, a total quantity of less than 100, may be higher than the second ratio and the third ratio of the metal plates showing a large total quantity, for example, a total quantity of 100 or more. In other words, the first ratio of the metal plates showing a small total quantity may be lower than the first ratio of the metal plates showing a large total quantity. For example, see the results of the seventh mask and the eighth mask shown in FIG. 48. Assume that a small total quantity is realized by increasing the range X1. The results of the embodiment suggest that when the range X1 exceeds a certain value, a phenomenon may occur in which the first ratio decreases as the range X1 increases. In other words, a decrease in the first ratio may suggest that an excessive amount of ingots or metal plates is being removed. The first ratio may be one of the useful indicators.

[0184] The first ratio of the metal plate may be, for example, 70% or more, 80% or more, or 90% or more. The first ratio of the metal plate may be, for example, 95% or less, 98% or less, or 100% or less. The range of the first ratio of the metal plate may be determined by a first group consisting of 70%, 80% and 90% and / or a second group consisting of 95%, 98% and 100%. The range of the first ratio of the metal plate may be determined by a combination of any one of the values ​​included in the above-mentioned first group and any one of the values ​​included in the above-mentioned second group. The range of the first ratio of the metal plate may be determined by a combination of any two of the values ​​included in the above-mentioned first group. The range of the first ratio of the metal plate may be determined by a combination of any two of the values ​​included in the above-mentioned second group. For example, it may be 70% or more and 100% or less, 70% or more and 98% or less, 70% or more and 95% or less, 70% or more and 90% or less, 70% or more and 80% or less, 80% or more and 100% or less, 80% or more and 98% or less, 80% or more and 95% or less, 80% or more and 90% or less, 90% or more and 100% or less, 90% or more and 98% or less, 90% or more and 95% or less, 95% or more and 100% or less, 95% or more and 98% or less, or 98% or more and 100% or less.

[0185] The specific method for removing the surface portion 64s is not particularly limited, but may be a so-called grinding method in which a grinding wheel is rotated to grind the surface of the first ingot 64i, or a so-called pushing method in which the first ingot 64i is pushed into a cutting tool to grind the surface of the first ingot 64i. The surface portion 64s may be removed by bringing a surface treatment liquid into contact with the surface of the first ingot 64i. The surface treatment liquid is, for example, an acidic solution such as a sulfuric acid solution or a sulfuric acid peroxide solution. The sulfuric acid peroxide solution is a solution containing sulfuric acid and hydrogen peroxide. The first surface treatment step may include only one of a process of grinding the surface of the first ingot 64i and a process of bringing the surface treatment liquid into contact with the surface of the first ingot 64i, or may include both. The first surface treatment step may be performed so that the thickness of the first ingot 64i is uniform.

[0186] Subsequently, the step of melting the ingot from which the surface portion has been removed in a melting furnace again may be repeated a predetermined number of times. For example, a second melting step may be further performed in which the first ingot is melted in a melting furnace to obtain a second ingot. Also, a third melting step may be further performed in which the second ingot is melted in a melting furnace to obtain a third ingot. The melting step may be repeated four or more times. Also, a surface treatment step may be performed between the melting steps to remove the surface portion of the ingot. For example, after the second melting step, a second surface treatment step may be performed to remove the surface portion of the second ingot. After the third melting step, a third surface treatment step may be performed to remove the surface portion of the third ingot. By repeatedly performing the melting step and the surface treatment step, the number and density of the particles 64d contained in the metal plate 64 can be further reduced.

[0187] The amount or size of particles contained in the metal plate can be adjusted by adjusting the number of times of the dissolving step and the surface treatment step. For example, the amount of particles contained in the metal plate can be reduced by increasing the number of times of the dissolving step and the surface treatment step. Alternatively, the circle equivalent diameter of particles contained in the metal plate can be reduced by increasing the number of times of the dissolving step and the surface treatment step.

[0188] The thickness of the surface portion removed from the ingot in the second surface treatment step and the third surface treatment step may be the same as or different from that in the first surface treatment step. The numerical range of the thickness of the surface portion removed in the second surface treatment step may be the same as or different from the numerical range of the thickness X1 described above. The numerical range of the thickness of the surface portion removed in the third surface treatment step may be the same as or different from the numerical range of the thickness X1 described above.

[0189] The processes for removing the surface portion of the ingot, such as the first surface treatment process, the second surface treatment process, and the third surface treatment process, are also referred to as "base material surface treatment processes."

[0190] The melting method in the second melting step, the third melting step and the subsequent melting steps may be the same as or different from the melting method in the first melting step. For example, vacuum arc melting, electroslag melting, etc. may be adopted. The second melting step and the third melting step are preferably carried out in a vacuum atmosphere.

[0191] The lower the pressure of the atmosphere in the melting process, the faster the upward movement speed of the particles 64d during the melting process may be. Therefore, by adjusting the pressure of the atmosphere, it may be possible to adjust the amount or size of the particles contained in the metal plate. For example, by lowering the pressure of the atmosphere, it is possible to reduce the amount of particles contained in the metal plate. Or, by lowering the pressure of the atmosphere, it is possible to reduce the circle equivalent diameter of the particles contained in the metal plate.

[0192] The times of the second dissolution step, the third dissolution step and any subsequent dissolution steps are also preferably set to allow the particles 64d to migrate to or around the surface.

[0193] Next, as shown in FIG. 38, a rolling process is performed to roll the base material 60 made of the ingot obtained by the melting process and the base material surface treatment process. For example, the base material 60 is conveyed toward a rolling device 66 including a pair of rolling rolls (work rolls) 66a, 66b while applying a tensile force in the direction indicated by the arrow D1. The base material 60 that has arrived between the pair of rolling rolls 66a, 66b is rolled by the pair of rolling rolls 66a, 66b, and as a result, the thickness of the base material 60 is reduced and the base material 60 is stretched along the conveying direction. This makes it possible to obtain a metal plate 64 that extends in the direction D1 and has a predetermined thickness. In the following description, the direction D1 in which the metal plate 64 extends is also referred to as the longitudinal direction D1. When the metal plate 64 is produced by rolling, a rolling streak extending in the longitudinal direction D1 is formed on the surface of the metal plate 64. As shown in FIG. 38, the metal plate 64 may be wound around a core 61 to form a rolled body 62.

[0194] FIG. 38 merely shows an outline of the rolling process, and the specific configuration and procedure for carrying out 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 arrangement of the iron alloy constituting the base material 60 is changed, or a cold rolling process in which the base material 60 is processed at a temperature equal to or lower than the temperature at which the crystal arrangement of the iron alloy is changed. In addition, the direction in which the base material 60 or the metal plate 64 is passed between a pair of rolling rolls 66a, 66b is not limited to one direction. For example, in FIG. 38, 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 a pair of rolling rolls 66a, 66b in a direction from the left side of the paper to the right side and a direction from the right side of the paper to the left side.

[0195] In the rolling process, the pressure of the rolling actuator may be adjusted to adjust the shape of the metal sheet 64. Furthermore, in addition to the rolling rolls (work rolls) 66a, 66b, the shape of the backup roll may be appropriately adjusted.

[0196] In the cold rolling process, a coolant such as kerosene may be supplied between the base material 60 and the rolling rolls 66a, 66b, thereby controlling the temperature of the base material.

[0197] An analysis step may be performed before, after, or during the rolling step to analyze the quality and characteristics of the base material 60 or the metal plate 64. For example, the base material 60 or the metal plate 64 may be irradiated with fluorescent X-rays to analyze the composition. The thermal expansion rate of the base material 60 or the metal plate 64 may be measured by thermomechanical analysis (TMA).

[0198] A metal plate surface treatment step for removing a surface portion of the metal plate 64 may be performed before the rolling step or between the hot rolling step and the cold rolling step. This can reduce the number and density of particles 64d contained in the metal plate 64. In addition, oxide coatings such as scale can be removed. The metal plate surface treatment step may be performed both before the rolling step and between the hot rolling step and the cold rolling step.

[0199] FIG. 60 is an enlarged cross-sectional view of the surface of the metal plate 64 and its surroundings before the surface portion 64u is removed. FIG. 61 is an enlarged cross-sectional view of the surface of the metal plate 64 and its surroundings after the surface portion 64u is removed. Reference symbol X3 indicates the thickness of the surface portion 64u to be removed. Reference symbol X4 indicates the thickness of the metal plate 64 before the surface portion 64u is removed. The specific method for removing the surface portion 64u is not particularly limited, but for example, the surface portion 64u can be removed by contacting the surface of the metal plate 64 with a surface treatment liquid. The surface treatment liquid is, for example, an acidic solution such as a sulfuric acid solution or a sulfuric acid peroxide solution, as in the case of the base material surface treatment process. When the metal plate surface treatment process is performed before the rolling process, the surface portion 64u may be removed by scraping the surface of the metal plate 64, as in the case of the base material surface treatment process. The metal plate surface treatment process may include only one of a process of contacting the surface of the metal plate 64 with a surface treatment liquid and a process of scraping the surface of the metal plate 64, or may include both.

[0200] The thickness X3 of the surface portion 64u removed by the metal plate surface treatment process may be, for example, 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more. The thickness X3 may be, for example, 30 μm or less, 50 μm or less, 70 μm or less, or 100 μm or less. The range of the thickness X3 may be determined by a first group consisting of 5 μm, 10 μm, 15 μm, and 20 μm, and / or a second group consisting of 30 μm, 50 μm, 70 μm, and 100 μm. The range of the thickness X3 may be determined by a combination of any one of the values ​​included in the first group described above and any one of the values ​​included in the second group described above. The range of the thickness X3 may be determined by a combination of any two of the values ​​included in the first group described above. The range of the thickness X3 may be determined by a combination of any two of the values ​​included in the second group described above. For example, it may be 5 μm or more and 100 μm or less, 5 μm or more and 70 μm or less, 5 μm or more and 50 μm or less, 5 μm or more and 30 μm or less, 5 μm or more and 20 μm or less, 5 μm or more and 15 μm or less, 5 μm or more and 10 μm or less, 10 μm or more and 100 μm or less, 10 μm or more and 70 μm or less, 10 μm or more and 50 μm or less, 10 μm or more and 30 μm or less, 10 μm or more and 20 μm or less, 10 μm or more and 15 μm or less, 15 μm or more and 100 μm or less, 15 μm or more and 70 μm or less, optionally 15 μm or more and 50 μm or less, optionally 15 μm or more and 30 μm or less, optionally 15 μm or more and 20 μm or less, optionally 20 μm or more and 100 μm or less, optionally 20 μm or more and 70 μm or less, optionally 20 μm or more and 50 μm or less, optionally 20 μm or more and 30 μm or less, optionally 30 μm or more and 100 μm or less, optionally 30 μm or more and 70 μm or less, optionally 30 μm or more and 50 μm or less, optionally 50 μm or more and 100 μm or less, optionally 50 μm or more and 70 μm or less, or optionally 70 μm or more and 100 μm or less.

[0201] The thickness X3 of the surface portion 64u may be determined based on a ratio to the thickness X4 of the metal plate 64 before the surface portion 64u is removed. X3 / X4 may be, for example, 0.01 or more, 0.02 or more, 0.03 or more, or 0.05 or more. X3 / X4 may be, for example, 0.10 or less, 0.15 or less, 0.20 or less, or 0.30 or less. The range of X3 / X4 may be determined by a first group consisting of 0.01, 0.02, 0.03, and 0.05, and / or a second group consisting of 0.10, 0.15, 0.20, and 0.30. The range of X3 / X4 may be determined by a combination of any one of the values ​​included in the first group described above and any one of the values ​​included in the second group described above. The range of X3 / X4 may be determined by a combination of any two of the values ​​included in the first group described above. The range of X3 / X4 may be determined by a combination of any two of the values ​​included in the second group described above. For example, it may be 0.01 or more and 0.30 or less, 0.01 or more and 0.20 or less, 0.01 or more and 0.15 or less, 0.01 or more and 0.10 or less, 0.01 or more and 0.05 or less, 0.01 or more and 0.03 or less, 0.01 or more and 0.02 or less, 0.02 or more and 0.30 or less, 0.02 or more and 0.20 or less, 0.02 or more and 0.15 or less, 0.02 or more and 0.10 or less, 0.02 or more and 0.05 or less, 0.02 or more and 0.03 or less, or 0.03 or more and 0.30 or less. Alternatively, the range may be 0.03 or more and 0.20 or less, 0.03 or more and 0.15 or less, 0.03 or more and 0.10 or less, 0.03 or more and 0.05 or less, 0.05 or more and 0.30 or less, 0.05 or more and 0.20 or less, 0.05 or more and 0.15 or less, 0.05 or more and 0.10 or less, 0.10 or more and 0.30 or less, 0.10 or more and 0.20 or less, 0.10 or more and 0.15 or less, 0.15 or more and 0.30 or less, 0.15 or more and 0.20 or less, or 0.20 or more and 0.30 or less.

[0202] When a surface treatment liquid is used, the thickness X3 of the surface portion 64u to be removed may be smaller than the above-mentioned thickness. For example, the thickness X3 may be 0.5 μm or more, 1.0 μm or more, 2.0 μm or more, or 3.0 μm or more. When a surface treatment liquid is brought into contact with the surface of the base material, the thickness X1 of the surface portion 64s to be removed may also be smaller than the above-mentioned thickness. For example, the thickness X1 may be 0.5 μm or more, 1.0 μm or more, 2.0 μm or more, or 3.0 μm or more.

[0203] Thereafter, in order to remove residual stress accumulated in the metal plate 64 by rolling, the metal plate 64 may be annealed using an annealing device 67 as shown in FIG. 39. The annealing process may be performed while pulling the metal plate 64 in the conveying direction (longitudinal direction) as shown in FIG. 39. That is, the annealing process may be performed as continuous annealing while conveying, not so-called batch-type annealing. In this case, it is preferable to set the temperature and conveying speed so as to suppress the occurrence of deformation such as buckling and bending in the metal plate 64. By carrying out the annealing process, it is possible to obtain a metal plate 64 from which residual strain has been removed to a certain extent. In FIG. 39, an example in which the metal plate 64 is conveyed in the horizontal direction during the annealing process is shown, but the present invention is not limited to this, and the metal plate 64 may be conveyed in other directions such as the vertical direction during the annealing process.

[0204] Thereafter, a slitting process may be performed in which both ends of the metal plate 64 obtained by the rolling process in the width direction are cut off over a predetermined range so that the width of the metal plate 64 falls within a predetermined range. This slitting process is performed to remove cracks that may occur on both ends of the metal plate 64 due to rolling. By performing such a slitting process, it is possible to prevent the phenomenon in which the metal plate 64 breaks, that is, so-called plate cuts, from occurring starting from the cracks.

[0205] 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 be performed before the above-mentioned annealing step.

[0206] At least two of the above-mentioned rolling, annealing and slitting steps may be repeated multiple times to produce a long metal plate 64 having a predetermined thickness.

[0207] After the rolling step, the annealing step, or the slitting step, an inspection step may be performed to inspect the density and dimensions of the particles 64d contained in the metal plate 64. In the inspection step, the above-mentioned observation step and analysis step are performed to inspect the density and dimensions of the particles 64d contained in the metal plate 64. 3 Information such as the number Z2 of particles 64d having an equivalent circle diameter of 1 μm or more contained per unit area, the equivalent circle diameter, and components is obtained.

[0208] Subsequently, a determination step may be performed to determine whether the metal plate 64 from which the sample 81 was taken out is a non-defective product. For example, when the above conditions (1) and (2) are satisfied, the metal plate 64 from which the sample 81 was taken out is determined to be a non-defective product.

[0209] In the judgment process, the metal plate 64 that satisfies the above conditions (3), (4), etc. in addition to the above conditions (1) and (2) may be judged to be a non-defective product. In the judgment process, the above conditions (1) to (4) may be arbitrarily combined. For example, the metal plate 64 that satisfies all of the judgment conditions (1) to (4) may be judged to be a non-defective product, or the metal plate 64 that satisfies only some of the judgment conditions (1) to (4) may be judged to be a non-defective product. Examples of combinations are shown below. Example 1: A metal plate 64 that satisfies condition (1) is judged to be a non-defective product. Example 2: A metal plate 64 that satisfies the condition (2) is judged to be a non-defective product. Example 3: A metal plate 64 that satisfies conditions (1) and (3) is judged to be a non-defective product. Example 4: A metal plate 64 that satisfies conditions (2) and (4) is judged to be a non-defective product. Example 5: A metal plate 64 that satisfies conditions (1) and (2) is judged to be a non-defective product. Example 6: A metal plate 64 that satisfies conditions (1), (2), and (3) is judged to be a non-defective product. Example 7: A metal plate 64 that satisfies conditions (1), (2), and (4) is judged to be a non-defective product. Example 8: A metal plate 64 that satisfies conditions (1), (2), (3), and (4) is judged to be a non-defective product.

[0210] In the judgment step, the metal plate 64 that further satisfies the above conditions (5), (6), (7), etc. in addition to the conditions shown in the above-mentioned Examples 1 to 8 may be judged as a good product. For example, the metal plate 64 that further satisfies the above condition (5) in addition to the conditions shown in the above-mentioned Examples 1 to 8 may be judged as a good product. For example, the metal plate 64 that further satisfies the above condition (6) in addition to the conditions shown in the above-mentioned Examples 1 to 8 may be judged as a good product. For example, the metal plate 64 that further satisfies the above conditions (5) and (7) in addition to the conditions shown in the above-mentioned Examples 1 to 8 may be judged as a good product. For example, the metal plate 64 that further satisfies the above conditions (6) and (7) in addition to the conditions shown in the above-mentioned Examples 1 to 8 may be judged as a good product. The following Examples 1A to 1D are examples in which the metal plate 64 that further satisfies one or two of the above conditions (5), (6), and (7) in addition to the conditions shown in the above-mentioned Example 1 is judged as a good product. Example 1A: A metal plate 64 that satisfies conditions (1) and (5) is judged to be a non-defective product. Example 1B: A metal plate 64 that satisfies conditions (1) and (6) is judged to be a non-defective product. Example 1C: A metal plate 64 that satisfies conditions (1), (5), and (7) is determined to be a non-defective product. Example 1D: A metal plate 64 that satisfies conditions (1), (6), and (7) is determined to be a non-defective product.

[0211] In the above description, an example has been shown in which the inspection process for inspecting the metal plate 64 based on the number, dimensions, components, etc. of the particles 64d is carried out to determine whether the metal plate 64 is good or bad, that is, to sort the metal plate 64. That is, an example has been shown in which the inspection process functions as a sorting process for sorting the metal plate 64 in the manufacturing method of the metal plate 64. However, the inspection process may be used for a purpose other than sorting the metal plate 64 in the manufacturing method of the metal plate 64.

[0212] An example will be described in which the inspection process is used for a purpose other than sorting the metal plate 64 in the manufacturing method of the metal plate 64. For example, inspection of the metal plate 64 based on the number, dimensions, components, etc. of the particles 64d may be used to optimize conditions of processes for preparing a base material, such as a melting process for melting raw materials in a melting furnace or a surface treatment process, or conditions of processes for manufacturing the metal plate 64, such as a rolling process, a metal plate surface treatment process, and an annealing process.

[0213] For example, first, the metal plate 64 is manufactured under various conditions, and the number and dimensions of the particles 64d contained in the sample 81 taken out of the metal plate 64 are calculated. In addition, the manufacturing conditions of the metal plate 64 are compared with the number and dimensions of the particles 64d contained in the sample 81 taken out of the obtained metal plate 64. This makes it possible to find conditions for manufacturing the metal plate 64 that satisfies the above-mentioned judgment conditions with a high probability. In this way, the inspection of the metal plate 64 based on the number and dimensions of the particles 64d may be used to find appropriate manufacturing conditions. In this case, it is not necessary to perform an inspection process for calculating the number and dimensions of the particles 64d for all of the metal plates 64 obtained in the actual manufacturing process. For example, the inspection process may be performed only on some of the metal plates 64. Or, once the manufacturing conditions are set, the inspection process for calculating the number and dimensions of the particles 64d may not be performed at all.

[0214] (Appearance inspection process) After the rolling step or the annealing step, a visual inspection step may be performed to inspect the visual appearance of the metal plate 64. The visual inspection step may include a step of inspecting the visual appearance of the metal plate 64 using an automatic inspection machine. The visual inspection step may include a step of visually inspecting the visual appearance of the metal plate 64.

[0215] (Shape inspection process) 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, the position of the surface of the metal plate 64 in the thickness direction may be measured within a predetermined region of the metal plate 64 using a three-dimensional measuring device.

[0216] Next, a method for manufacturing the deposition mask 20 using the metal plate 64 that satisfies the above-mentioned determination condition will be described mainly with reference to FIGS. 40 to 43. FIG. 40 is a diagram showing a manufacturing apparatus 70 for manufacturing the deposition mask 20 using the metal plate 64. First, a metal plate 64 extending in a longitudinal direction D1 is prepared. The metal plate 64 is prepared in the state of a roll 62 in which the metal plate 64 is wound around the above-mentioned core 61, for example. Next, the metal plate 64 is transported sequentially to a resist film forming apparatus 71, an exposure / developing apparatus 72, an etching apparatus 73, and a separating apparatus 74 shown in FIG. 40. FIG. 40 shows an example in which the metal plate 64 moves between the apparatuses by being transported in the longitudinal direction D1, but is not limited thereto. After the metal plate 64 is wound in a predetermined apparatus, the metal plate 64 in the state of a roll may be supplied to an apparatus downstream.

[0217] The resist film forming device 71 provides a resist film on the surface of the metal plate 64. The exposure / development device 72 performs exposure processing and development processing on the resist film, thereby patterning the resist film to form a resist pattern.

[0218] The etching device 73 forms the through holes 25 in the metal plate 64 by etching the metal plate 64 using a resist pattern as a mask. 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. For example, a large number of through holes 25 are formed in the metal plate 64 such that a plurality of effective areas 22 are aligned in the width direction D2 of the metal plate 64 and that the effective areas 22 for a plurality of deposition masks 20 are aligned in the longitudinal direction D1 of the metal plate 64.

[0219] The separating device 74 performs a separating step of separating a portion of the metal plate 64 in which a plurality of through holes 25 corresponding to one deposition mask 20 is formed, from the metal plate 64. In this manner, a sheet-like deposition mask 20 can be obtained.

[0220] In the manufacturing process of the deposition mask 20, first, a resist film is provided on the surface of the metal plate 64 using a resist film forming apparatus 71. Then, the resist films 65a, 65b are exposed and developed using an exposure / development apparatus 72. As a result, a first resist pattern 65c can be formed on the first surface 64a of the metal plate 64, and a second resist pattern 65d can be formed on the second surface 64b of the metal plate 64, as shown in FIG.

[0221] Next, the metal plate 64 is etched using an etching device 73 with the resist patterns 65c and 65d as masks. First, as shown in FIG. 42, a region of the first surface 64a of the metal plate 64 that is not covered by the first resist pattern 65c is etched with a first etching solution to form a first recess 30. Next, the first recess 30 is covered with a resin 69. Thereafter, as shown in FIG. 43, a region of the second surface 64b of the metal plate 64 that is not covered by the second resist pattern 65d is etched to form a second recess 35 on the second surface 64b. Thereafter, the resin 69 and the resist patterns 65c and 65d are removed from the metal plate 64.

[0222] 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 is formed is separated from the other portion of the metal plate 64. In this way, the deposition mask 20 can be obtained.

[0223] Next, an inspection process is carried out to check whether the deviation of the area of ​​the through holes 25 formed in the metal plate 64 from a reference value is equal to or less than a predetermined tolerance. The reference value and the tolerance are set according to the pixel density of the display device manufactured using the deposition mask 20, the average value of the dimensions of the through holes 25, and the like. For example, in the case of a deposition mask 20 used to manufacture a WQHD (Wide Quad High Definition) display device, the tolerance is 5 μm 2 Above 400μm 2 In the case of the deposition mask 20 in which the average value of the circle-equivalent diameter of the through holes 25 is 30 μm±3 μm, the tolerance is 5 μm. 2More than 150μm 2 In the through-hole inspection process, if the deposition mask 20 contains even one through-hole 25 whose deviation from the reference area exceeds a tolerance, the deposition mask 20 is rejected as a defective product.

[0224] As a method for measuring the area of ​​the through hole 25, a method using light transmitted through the through hole 25 can be employed. Specifically, parallel light is incident on one of the first surface 20a or the second surface 20b of the deposition mask 20 along the normal direction of the metal plate 64, and is transmitted through the through hole 25 to be emitted from the other of the first surface 20a or the second surface 20b. Then, the area of ​​the region occupied by the emitted light in the surface direction of the metal plate 64 is measured as the area of ​​the through hole 25. In this case, the outline in a plan view of the through portion 42 where the opening area of ​​the through hole 25 is the smallest determines the area of ​​the region occupied by the light emitted from the deposition mask 20 in the surface direction of the metal plate 64.

[0225] If particles 64d, 64e fall off from metal plate 64 during the etching process of etching metal plate 64 to form through hole 25, reduced through holes 25B, 25C smaller than standard through hole 25A and enlarged through holes 25D, 25E ​​larger than standard through hole 25A may be formed as shown in Fig. 25 above. As a result, the dimensions of through portion 42 may partially become dimensions SB, SC smaller than dimension SA of standard through hole 25A and dimensions SD, SE larger than dimension SA. Such deviations in dimensions cause deviations in the area of ​​through hole 25 from the reference value.

[0226] In this embodiment, by using the metal plate 64 that satisfies the above-mentioned conditions (1) and (2), it is possible to prevent the formation of the reduced through holes 25B, 25C and the enlarged through holes 25D, 25E ​​caused by the falling off of the particles 64d, 64e, and thus to prevent the area of ​​the through hole 25 from deviating from the reference value.

[0227] In the inspection step of the through holes, in addition to or instead of evaluating the absolute value of the area of ​​the through holes 25 as described above, a relative value of the area of ​​the through holes 25 may be evaluated. For example, when the area of ​​one through hole 25 is S1 and the average value of the areas of the through holes 25 surrounding the through hole 25 is S2, it may be evaluated whether the absolute value of (S1-S2) / S2 is equal to or less than a predetermined threshold value. The threshold value in this case is also appropriately set according to the pixel density of the display device manufactured using the deposition mask 20, the average value of the dimensions of the through holes 25, and the like. In this embodiment, by using the metal plate 64 that satisfies the above-mentioned conditions (1) and (2), it is possible to prevent the absolute value of (S1-S2) / S2 from exceeding a predetermined threshold value.

[0228] When the deposition mask 20 is manufactured using the metal plate 64 that satisfies the above-mentioned conditions (1) and (2), the deposition mask 20 may also satisfy the above-mentioned conditions (1) and (2). For example, the through-holes 25 are not formed in the deposition mask 20, such as the ends 17a, 17b and the peripheral region 23 of the middle portion 18, and therefore the portions that are covered with the resist pattern in the manufacturing process of the deposition mask 20 are not contacted with the etching solution in the manufacturing process. Therefore, in the ends 17a, 17b and the peripheral region 23, the distribution state of the particles 64d in the metal plate 64 before the through-holes 25 are formed can be maintained. In other words, in the portions of the deposition mask 20 that do not contact the etching solution, the particles 64d in the metal plate 64 remain without falling off. Therefore, when the sample 81 taken out from the ends 17a, 17b and the peripheral region 23 of the deposition mask 20 is dissolved and the particles 64d are analyzed, the same analysis result as in the case of the metal plate 64 before the through-holes 25 are formed can be obtained. Therefore, by taking out and analyzing samples 81 from the ends 17a, 17b or the surrounding area 23 of the deposition mask 20, information regarding the distribution state of the particles 64d in the metal plate 64 used to manufacture the deposition mask 20 can be obtained.

[0229] In this embodiment, as described above under condition (1), the volume of the sample 81 taken out from the metal plate 64 is 1 mm3 The number of particles having a circle equivalent diameter of 1 μm or more and less than 3 μm per unit area is 50 or more. When the particles 64d are exposed on the surface of the metal plate 64, the particles 64d can contribute to improving the adhesion between the resist films 65a, 65b and the metal plate 64. In addition, the anchor effect of the particles 64d on the resist films 65a, 65b can also contribute to improving the adhesion between the resist films 65a, 65b and the metal plate 64. Therefore, it is possible to suppress the resist films 65a, 65b of the resist patterns 65c, 65d from peeling off from the metal plate 64 during the manufacturing process of the deposition mask 20, such as the etching process. This makes it easier to adopt the resist films 65a, 65b with small dimensions. This makes it easier to shorten the arrangement period of the through holes 25 of the deposition mask 20, and makes it possible to manufacture a display device with high pixel density.

[0230] By carrying out the above-mentioned base material surface treatment step or metal layer surface treatment step, the number and density of particles 64d contained in the metal plate 64 can be reduced. Therefore, the probability of manufacturing a metal plate 64 satisfying condition (1) can be increased. By adjusting the thickness of the surface portion removed by the base material surface treatment step or metal layer surface treatment step, the probability of manufacturing a metal plate 64 satisfying condition (1) can be adjusted. Similarly, by adjusting the thickness of the surface portion removed by the base material surface treatment step or metal layer surface treatment step, the probability of manufacturing a metal plate 64 satisfying other conditions (2) to (7) can be adjusted. Similarly, by adjusting the thickness of the surface portion removed by the base material surface treatment step or metal layer surface treatment step, the first ratio, the second ratio, and the third ratio of the metal plate 64 can be adjusted. Only one of the base material surface treatment step and the metal layer surface treatment step may be carried out, or both may be carried out.

[0231] Next, a fixing step is performed in which the deposition mask 20 obtained as described above is fixed to the frame 15. In this manner, the deposition mask device 10 including the deposition mask 20 and the frame 15 can be obtained. In the fixing step, first, a stretching step is performed in which the position of the deposition mask 20 with respect to the frame 15 is adjusted while tension is applied to the deposition mask 20. In the stretching step, for example, ends 17a and 17b of the deposition mask 20 are clamped and held by clamps (not shown). Next, while applying tension to the deposition mask 20, the position and tension of the deposition mask 20 are adjusted so that the difference between the positions of the through-holes 25 of 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, 3 μm. Next, a welding step is performed in which the end 17 of the deposition mask 20 is heated while the end 17 is in contact with the frame 15, and the end 17 is welded to the frame 15. For example, a pulsed laser beam is irradiated to the end 17, and a plurality of points of the end 17 are welded to the frame 15. In this manner, the deposition mask 20 can be fixed to the frame 15.

[0232] Next, a deposition method for depositing a deposition material 98 on a substrate such as an organic EL substrate 92 using the deposition mask 20 according to the present embodiment will be described. First, the deposition mask device 10 is arranged so that the deposition mask 20 faces the organic EL substrate 92. The deposition mask 20 is brought into close contact with the organic EL substrate 92 using a magnet 93. In this state, the deposition material 98 is evaporated and caused to fly to the organic EL substrate 92 through the deposition mask 20, so that the deposition material 98 can be attached to the organic EL substrate 92 in a pattern corresponding to the through-holes 25 of the deposition mask 20. Here, in the deposition mask 20 according to the present embodiment, as described above, the accuracy of the shape of the through-holes 25 is suppressed from decreasing due to particles. Therefore, the accuracy of the area, shape, thickness, and the like of the deposition material 98 attached to the organic EL substrate 92 can be improved.

[0233] Various modifications can be made to the above-described embodiment. Below, the modified examples will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment will be used for parts configured similarly to the above-described embodiment, and duplicated descriptions will be omitted. If it is clear that the effects obtained in the above-described embodiment can also be obtained in the modified examples, the description may be omitted.

[0234] First, a modified method for manufacturing the metal plate 64 will be described. Fig. 44 is a schematic diagram for explaining an entire modified method for manufacturing the deposition mask 20. The manufacturing apparatus 70 shown in Fig. 44 is different only in that it includes a thinning apparatus 75 located upstream of a resist film forming apparatus 71, and other configurations are the same as the above-mentioned manufacturing apparatus 70 shown in Fig. 40.

[0235] The thinning device 75 is a device that reduces the thickness of the metal sheet 64 unwound from the roll. The thinning device 75 reduces the thickness of the metal sheet 64, for example, by etching at least the entire portion of the metal sheet 64 that corresponds to the effective region 22. By thinning the metal sheet 64, it is possible to obtain a metal sheet 64 having a small thickness even in cases where it is difficult to increase the reduction rate in the rolling process.

[0236] Next, a modified example of the process of forming the through hole 25 in the metal plate 64 in the manufacturing method of the metal plate 64 will be described. In the above-mentioned embodiment, an example has been shown in which the process of forming the through hole 25 in the metal plate 64 includes a first-side etching process of etching the metal plate 64 from the first side 64a side and a second-side etching process of etching the metal plate 64 from the second side 64b side. However, this is not limited to this, and the process of forming the through hole 25 in the metal plate 64 may include laser processing of processing the through hole 25 by irradiating the metal plate 64 with a laser. In this case, the laser processing may be performed instead of the first-side etching process, as described below.

[0237] First, as shown in FIG. 45, a second resist pattern 65d is formed on the second surface 64b of the metal plate 64. Then, as shown in FIG. 46, a second surface etching step is performed in which a region of the second surface 64b of the metal plate 64 that is not covered by the second resist film 65b is etched to form a second recess 35 on the second surface 64b. Thereafter, as shown in FIG. 47, a laser processing step is performed in which a laser L is irradiated onto a part of the portion of the metal plate 64 where the second recess 35 is formed, to form a first recess 30 penetrating from the wall surface of the second recess 35 to the first surface 64a. As shown in FIG. 47, the laser L1 may be irradiated from the second surface 64b side of the metal plate 64.

[0238] 45 to 47, if particles 64d fall off from metal plate 64 in the second-side etching step, the dimensions of through-hole 25 may deviate from the design values ​​or vary in size. For this reason, it is useful to use metal plate 64 that satisfies the above-mentioned conditions (1) and (2) in the examples shown in Fig. 45 to 47 as well.

[0239] 47, the wall surface 31 of the first recess 30 formed by laser processing may be inclined so as to be displaced toward the center of the through hole 25 in a plan view from the second surface 64b toward the first surface 64a. In this case, the end of the first recess 30 on the first surface 64a defines the through portion 42 where the opening area of ​​the through hole 25 is the smallest in a plan view.

[0240] Next, a modified example of the inspection step will be described. In the above-described embodiment, an example has been shown in which the inspection step for inspecting the density and dimensions of the particles 64d contained in the metal plate 64 is performed on the metal plate 64 before the through holes 25 are formed. However, the present invention is not limited to this, and the inspection step for inspecting the particles 64d contained in the metal plate 64 may be performed on the metal plate 64 after the through holes 25 are formed, that is, on the deposition mask 20. In this case, the sample 81 may be taken out from a portion of the metal plate 64 where the through holes 25 are not formed, such as the ends 17a and 17b or the surrounding area 23 of the deposition mask 20, and the particles 64d may be inspected. When the sample 81 is taken out from a portion of the metal plate 64 where the through holes 25 are not formed, the dissolved volume of the sample 81 can be calculated based on the thickness of the metal plate 64 constituting the deposition mask 20, and the area and number of the sample pieces 81a taken out of the sample 81. The sample 81 may be taken out from a portion of the metal plate 64 where the through holes 25 are formed, and the particles 64d may be inspected. In this case, the dissolution volume of the sample 81 may be calculated based on the measured weight of the sample 81 and data on the density of the material that constitutes the sample 81 . EXAMPLES

[0241] Next, the embodiments of the present disclosure will be described more specifically with reference to examples. However, the embodiments of the present disclosure are not limited to the description of the following examples as long as they do not depart from the gist of the disclosure.

[0242] Example 1 First, iron, nickel and other raw materials were prepared so that the ratio of iron and nickel to the total raw materials was about 64% by weight and about 36% by weight, respectively. Next, the raw materials were crushed as necessary, and then the first melting process was carried out in which the raw materials were melted in a melting furnace. In the first melting process, aluminum, manganese and silicon were put into the melting furnace for deoxidization, dehydration, denitrification and the like. The first melting process was carried out in an inert gas atmosphere under a low pressure state lower than atmospheric pressure. Next, a first surface treatment process was carried out in which the surface portion of the first ingot obtained by the first melting process was removed. The thickness of the removed surface portion was 10 mm or more.

[0243] Subsequently, a second melting step was performed in which the first ingot from which the surface portion was removed in the first surface treatment step was melted in a melting furnace to obtain a second ingot, and a second surface treatment step was performed in which the surface portion of the second ingot was removed. The thickness of the removed surface portion was 10 mm or more. In this manner, a base material composed of an iron alloy containing nickel, the remainder being iron, and unavoidable impurities was prepared.

[0244] Next, the base material was subjected to the above-mentioned rolling process, annealing process, and slit process to produce a roll (first roll) in which a metal plate having a thickness of 20 μm was wound. Then, the deposition mask 20 was produced by the manufacturing method shown in FIG. 6 to FIG. 11 using the metal plate 64 of the first roll. The deposition mask 20 produced from the metal plate 64 of the first roll is also referred to as the first mask. Then, a square sample 81 with a side length K1 of 60 mm was cut out from the first end portion 17a of the first mask. The sample 81 includes the first surface 64a and the second surface 64b of the metal plate 64 constituting the first end portion 17a of the first mask. In addition, three circular sample pieces 81a with a diameter K2 of 20 mm were punched out from the sample 81. Then, the sample piece 81a was ultrasonically cleaned with pure water to remove foreign matter adhering to the sample piece 81a. The ultrasonic frequency was set to 28 kHz, and the ultrasonic cleaning time was set to 10 seconds.

[0245] Next, a sample dissolving step was carried out to dissolve the sample pieces 81a in the aqueous solution 83. Specifically, a beaker having a volume of 500 ml was prepared as the container 82, and three sample pieces 81a were placed in the beaker. Next, 100 ml of the aqueous solution 83 at 50° C. was poured into the beaker to dissolve the sample pieces 81a. At this time, the beaker was shaken for the first 15 minutes, and then the beaker was kept stationary for the next 15 minutes, so that the sample pieces 81a were dissolved in the aqueous solution 83 in the beaker for a total of 30 minutes. An aqueous solution containing nitric acid was used as the aqueous solution 83. Specifically, the aqueous solution 83 was prepared by mixing 500 ml of nitric acid solution and 500 ml of pure water. Special grade nitric acid (1.38) manufactured by Hayashi Pure Chemical Industries Co., Ltd. was used as the nitric acid solution. Special grade nitric acid (1.38) is an aqueous solution containing nitric acid at a concentration of 60% by weight.

[0246] Next, a filtration step was carried out to remove particles from the aqueous solution 83 in which the sample pieces 81a were dissolved, using a suction filtration device. As the filter paper, a membrane filter JHWP02500 manufactured by MILLIPORE was used. The diameter of the pores of JHWP02500, i.e., the pore size, was 0.45 μm. Therefore, it is considered that particles having a size of at least 1 μm or more will remain on the JHWP02500. As a pressure reducing section for reducing the pressure in the space downstream of the filter paper, a suction and pressure dual-purpose chemical duty pump WP6110060 manufactured by MILLIPORE was used. In addition, after filtering the aqueous solution in the beaker once with the filter paper, a rinsing step of injecting pure water into the beaker and filtering the pure water with the filter paper was carried out three times.

[0247] The above-mentioned particle drying step was then carried out to dry the filter paper and the particles remaining on the filter paper.

[0248] Next, the above-mentioned observation process was carried out using an SEM to detect particles on the filter paper. As the SEM, a polar scanning electron microscope JSM7800FPRIME manufactured by JEOL Ltd. was used. The SEM settings and the method of adjusting the contrast and / or brightness of the SEM were as described above. Next, the detected particles were analyzed using Particle Phaze Analysis version 6.53, an automatic particle analysis software manufactured by AMETECH Co., Ltd. In addition, a composition analysis of the particles was carried out using an EDX device manufactured by AMETECH Co., Ltd., Octane Elect. As a result, particles containing elements other than iron and nickel as main components and having a circle equivalent diameter of 1 μm or more were extracted. In addition, the volume of sample 81 was measured using a 1 mm2 sample. 3 The number of particles contained per 1 mm and the equivalent circle diameter of each particle were calculated. 3 The number of particles having an equivalent circle diameter of 1 μm or more contained per unit area (hereinafter also referred to as the total number) was 924.

[0249] As shown in Figure 48, sample 81 had a volume of 1 mm 3 Among the particles contained per mask, the number of particles having an equivalent circle diameter of 1 μm or more and less than 3 μm (hereinafter also referred to as the first number) was 912, the number of particles having an equivalent circle diameter of 3 μm or more and less than 5 μm (hereinafter also referred to as the second number) was 12, and the number of particles having an equivalent circle diameter of 5 μm or more (hereinafter also referred to as the third number) was 0. The number of particles having an equivalent circle diameter of 3 μm or more is 12. Therefore, the metal plate of the first mask satisfies the above-mentioned conditions (1), (2), (3), and (4).

[0250] In addition, the ratio of the first quantity (hereinafter also referred to as the first ratio), the ratio of the second quantity (hereinafter also referred to as the second ratio), and the ratio of the third quantity (hereinafter also referred to as the third ratio) to the total quantity of particles having an equivalent circle diameter of 1 μm or more were calculated. As shown in parentheses under the first quantity, second quantity, and third quantity in Figure 48, the first ratio was 98.7%, the second ratio was 1.3%, and the third ratio was 0.0%.

[0251] In addition, the composition of particles having a circle equivalent diameter of 1 μm or more was analyzed using an EDX device. 3 Of the particles contained per unit area, there were 6 particles whose main component was magnesium (hereinafter also referred to as Mg quantity), 770 particles whose main component was aluminum (hereinafter also referred to as Al quantity), 80 particles whose main component was silicon (hereinafter also referred to as Si quantity), 0 particles whose main component was phosphorus (hereinafter also referred to as P quantity), 37 particles whose main component was zirconium (hereinafter also referred to as Zr quantity), and 31 particles whose main component was sulfur (hereinafter also referred to as S quantity).

[0252] Examples 2-4 As in Example 1, iron, nickel and other raw materials were prepared so that the ratio of iron and nickel to the total raw materials was about 64% by weight and about 36% by weight, respectively. Then, each raw material was crushed as necessary, and then the first melting step, the first surface treatment step, the second melting step and the second surface treatment step were performed to prepare a base material. Then, the base material was subjected to a rolling step, an annealing step and a slitting step to produce the second to fourth wound bodies, each of which was wound with a metal plate 64 having a thickness of 20 μm. The manufacturing conditions for the second to fourth wound bodies were roughly the same as those for the first wound body, but differed in detail. Specifically, the manufacturing conditions for the second to fourth wound bodies differ from those for the first wound body in at least one of the following (A) to (D). In addition, the manufacturing conditions for the second to fourth wound bodies differ from each other in at least one of the following (A) to (D). (A) Amount of additive in the first dissolution step (B) Thickness of the surface portion to be removed in the first surface treatment step (C) Number of dissolution steps (D) Atmospheric pressure in the first melting step

[0253] As in the case of Example 1 described above, deposition masks 20 were manufactured by the manufacturing method shown in Figs. 6 to 11 using the metal plates 64 of the second to fourth winding bodies. The deposition masks 20 manufactured from the metal plates 64 of the second to fourth winding bodies are also referred to as the second to fourth masks. Next, particles contained in each sample 81 taken out from the first end portion 17a of the second to fourth masks were observed using an SEM, and the particles per mm2 of the sample 81 were 3 The number of particles contained per unit area and the equivalent circle diameter of each particle were calculated. The results are shown in Figure 48. Furthermore, in the same manner as in Example 1 above, the composition of particles having an equivalent circle diameter of 1 μm or more was analyzed using an EDX device. The results are shown in Figure 49.

[0254] Examples 5-12 As in Example 1, iron, nickel and other raw materials were prepared so that the ratio of iron and the ratio of nickel to the entire raw materials were about 64% by weight and about 36% by weight, respectively. Then, after each raw material was crushed as necessary, the first melting step, the first surface treatment step, the second melting step and the second surface treatment step were carried out to produce a second ingot. Then, the third melting step was carried out in a melting furnace to obtain a third ingot from the second ingot whose surface portion was removed in the second surface treatment step, and the third surface treatment step was carried out to remove the surface portion of the third ingot. The thickness of the removed surface portion was 10 mm or more. In this way, a base material composed of an iron alloy containing nickel, the remaining iron and unavoidable impurities was prepared. Then, the base material was subjected to a rolling step, an annealing step and a slitting step to produce the fifth to twelfth winding bodies, each of which was wound with a metal plate 64 having a thickness of 20 μm. The manufacturing conditions of the fifth to twelfth winding bodies were roughly the same, but the details were different. Specifically, the manufacturing conditions of the fifth to twelfth winding bodies are different from each other in at least one of the following (A) to (D). (A) Amount of additive in the first dissolution step (B) Thickness of the surface portion to be removed in the first surface treatment step (C) Number of dissolution steps (D) Atmospheric pressure in the first melting step

[0255] In the same manner as in Example 1, deposition masks 20 were manufactured by the manufacturing method shown in Figs. 6 to 11 using the metal plates 64 of the fifth to twelfth windings. The deposition masks 20 manufactured from the metal plates 64 of the fifth to twelfth windings are also referred to as the fifth to twelfth masks, respectively. Next, particles contained in each sample taken out from the first end portion 17a of the fifth to twelfth masks were observed using an SEM, and the number of particles and the circle equivalent diameter of each particle were calculated. The results are shown in Fig. 48.

[0256] Moreover, the composition of particles having an equivalent circle diameter of 1 μm or more was analyzed in the same manner as in the above-mentioned Example 1. The results are shown in FIG.

[0257] When the metal plate 64 of the seventh winding body was used, a phenomenon occurred in which the resist film peeled off from the metal plate 64 during the etching process in which the through-holes 25 were formed by etching the metal plate 64. For this reason, it was not possible to manufacture a deposition mask 20 from the metal plate 64 of the seventh winding body. The measurement results shown in the row of "7th Mask" in Figs. 48 and 49 are the results of observing, using an SEM, particles contained in a sample taken out of the metal plate 64 of the seventh winding body, and the results of analyzing the composition of the particles.

[0258] Examples 13-17 As in Example 1, iron, nickel and other raw materials were prepared so that the ratio of iron and nickel to the total raw materials was about 64% by weight and about 36% by weight, respectively. Then, each raw material was crushed as necessary, and then the first melting step and the first surface treatment step were carried out to produce a base material. Then, the base material was subjected to a rolling step, an annealing step and a slitting step to produce the 13th to 17th winding bodies, each of which was wound with a metal plate 64 having a thickness of 20 μm. The manufacturing conditions for the 13th to 17th winding bodies are generally the same but differ in detail. Specifically, the manufacturing conditions for the 13th to 17th winding bodies differ from each other in at least one of the following (A) to (D). (A) Amount of additive in the first dissolution step (B) Thickness of the surface portion to be removed in the first surface treatment step (C) Number of dissolution steps (D) Atmospheric pressure in the first melting step

[0259] As in the case of Example 1 described above, deposition masks 20 were manufactured by the manufacturing method shown in Figs. 6 to 11 using the metal plates 64 of the 13th to 17th windings. The deposition masks 20 manufactured from the metal plates 64 of the 13th to 17th windings are also referred to as the 13th to 17th masks, respectively. Next, particles contained in each sample 81 taken out from the first end portion 17a of the 13th to 17th masks were observed using an SEM, and the particles per mm2 of the sample 81 were 3 The number of particles contained per unit area and the equivalent circle diameter of each particle were calculated. The results are shown in Figure 48. Furthermore, in the same manner as in Example 1 above, the composition of particles having an equivalent circle diameter of 1 μm or more was analyzed using an EDX device. The results are shown in Figure 49.

[0260] Examples 21-22 As in Example 1, iron, nickel and other raw materials were prepared so that the ratio of iron and nickel to the total raw materials was about 64% by weight and about 36% by weight, respectively. Then, each raw material was crushed as necessary, and then the first melting step, the first surface treatment step, the second melting step and the second surface treatment step were carried out to produce a base material. Then, the base material was subjected to a rolling step, an annealing step and a slitting step to produce the 21st winding body and the 22nd winding body in which the metal plate 64 was wound. The metal plate 64 of the 21st winding body had a thickness of 50 μm. The metal plate 64 of the 22nd winding body had a thickness of 80 μm.

[0261] As in the case of Example 1 described above, the deposition mask 20 was manufactured by the manufacturing method shown in Figs. 6 to 11 using the metal plates 64 of the 21st winding and the 22nd winding. The deposition masks 20 manufactured from the metal plates 64 of the 21st winding and the 22nd winding are also referred to as the 21st mask and the 22nd mask. Next, the particles contained in each sample 81 taken out from the first end portion 17a of the 21st mask and the 22nd mask were observed using an SEM, and the particles per mm2 of the sample 81 were measured. 3 The number of particles contained per unit area and the equivalent circle diameter of each particle were calculated. The results are shown in Figure 48. Furthermore, in the same manner as in Example 1 above, the composition of particles having an equivalent circle diameter of 1 μm or more was analyzed using an EDX device. The results are shown in Figure 49.

[0262] Example 23 As in Example 1, iron, nickel and other raw materials were prepared so that the ratio of iron and nickel to the total raw materials was about 64% by weight and about 36% by weight, respectively. Next, each raw material was crushed as necessary, and then the first melting step and the first surface treatment step were carried out to produce a base material. Next, the base material was subjected to a rolling step, an annealing step and a slitting step to produce a 23rd winding body in which a metal plate 64 was wound. The metal plate 64 of the 23rd winding body had a thickness of 70 μm.

[0263] In the same manner as in Example 1 described above, the deposition mask 20 was manufactured by the manufacturing method shown in Figs. 6 to 11 using the metal plate 64 of the 23rd winding body. The deposition mask 20 manufactured from the metal plate 64 of the 23rd winding body is also referred to as the 23rd mask. Next, the particles contained in each sample 81 taken out from the first end portion 17a of the 23rd mask were observed using an SEM, and the particles per mm2 of the sample 81 were 3 The number of particles contained per unit area and the equivalent circle diameter of each particle were calculated. The results are shown in Figure 48. Furthermore, in the same manner as in Example 1 above, the composition of particles having an equivalent circle diameter of 1 μm or more was analyzed using an EDX device. The results are shown in Figure 49.

[0264] Examples 24-25 As in Example 1, iron, nickel and other raw materials were prepared so that the ratio of iron and nickel to the total raw materials was about 64% by weight and about 36% by weight, respectively. Then, after each raw material was crushed as necessary, the first melting step, the first surface treatment step, the second melting step and the second surface treatment step were carried out to produce a second ingot. Then, the second ingot, the surface portion of which was removed in the second surface treatment step, was melted in a melting furnace to obtain a third ingot, and the third surface treatment step was further carried out to remove the surface portion of the third ingot. The thickness of the removed surface portion was 10 mm or more. In this way, a base material composed of an iron alloy containing nickel, the remaining iron and unavoidable impurities was prepared. Then, the base material was subjected to a rolling step, an annealing step and a slitting step to manufacture the 24th winding body and the 25th winding body, each of which had a metal plate 64 wound thereon. The metal plate 64 of the 24th winding body has a thickness of 60 μm. The metal plate 64 of the 25th winding has a thickness of 16 μm.

[0265] In the same manner as in Example 1 described above, deposition masks 20 were manufactured by the manufacturing method shown in Figs. 6 to 11 using the metal plates 64 of the 24th winding and the 25th winding. The deposition masks 20 manufactured from the metal plates 64 of the 24th winding and the 25th winding are also referred to as the 24th mask and the 25th mask. Next, particles contained in each sample 81 taken out from the first end portion 17a of the 24th mask and the 25th mask were observed using an SEM, and the number of particles per mm2 of the sample 81 was calculated. 3 The number of particles contained per unit area and the equivalent circle diameter of each particle were calculated. The results are shown in Figure 48. Furthermore, in the same manner as in Example 1 above, the composition of particles having an equivalent circle diameter of 1 μm or more was analyzed using an EDX device. The results are shown in Figure 49.

[0266] Next, evaluations A and B were performed on the accuracy of the areas of the through-holes 25 of the 1st to 17th masks and the 21st to 25th masks.

[0267] (Accuracy of through hole area rating A) It was evaluated whether the area of ​​the through holes 25 of the deposition mask 20 was within a predetermined allowable range. Specifically, as shown in FIG. 62, the area S1 of one through hole 25X and the average value S2 of the areas of the through holes 25Y surrounding the through hole 25X were measured. In the example shown in FIG. 62, the number of the through holes 25Y is 4. Then, it was evaluated whether the absolute value of (S1-S2) / S2 was equal to or less than a first threshold value. The first threshold value is set according to the pixel density of the display device manufactured using the deposition mask 20, the average value of the dimensions of the through holes 25, and the like. For example, in the case of a deposition mask 20 in which the average value of the circle-equivalent diameter of the through holes 25 is 30 μm, the first threshold value is 0.20.

[0268] The method of measuring the area of ​​the through holes 25 employs a method of using light transmitted through the through holes 25. Specifically, parallel light is incident on one of the first surface 20a or the second surface 20b of the deposition mask 20 along the normal direction of the metal plate 64, and is transmitted through the through holes 25 to be emitted from the other of the first surface 20a or the second surface 20b. Then, the area of ​​the area occupied by the emitted light in the surface direction of the metal plate 64 is measured by photographing the area by a camera. The measurement result is employed as the area of ​​each through hole 25. In this case, the outline of the through portion 42 of the deposition mask 20 in a plan view determines the area of ​​the area occupied by the light emitted from the deposition mask 20 in the surface direction of the metal plate 64.

[0269] The results of the evaluation are shown in the columns "Evaluation A-1" and "Evaluation A-2" in FIG. 48. In the column "Evaluation A-1", "OK" indicates that the absolute value of (S1-S2) / S2 was 0.20 or less in all the through holes 25 of the deposition mask 20, and "NG" indicates that (S1-S2) / S2 exceeded 0.20 in at least some of the through holes 25. In the column "Evaluation A-2", "OK" indicates that the absolute value of (S1-S2) / S2 was 0.20 or less in all the through holes 25 of the deposition mask 20, and "NG" indicates that (S1-S2) / S2 was less than -0.20 in at least some of the through holes 25. Therefore, when the above-mentioned enlarged through holes are generated, NG is likely to appear in the evaluation A-1, and when the above-mentioned reduced through holes are generated, NG is likely to appear in the evaluation A-2. The number of through holes 25 evaluated per one deposition mask 20 was more than 25 million.

[0270] (Evaluation of the accuracy of the area of ​​the through hole B) Whether or not the absolute value of the above-mentioned (S1-S2) / S2 is equal to or less than a second threshold smaller than the first threshold is evaluated. The second threshold is set according to the pixel density of a display device manufactured using the deposition mask 20, the average value of the dimensions of the through holes 25, and the like. For example, in the case of a deposition mask 20 in which the average value of the circle-equivalent diameter of the through holes 25 is 20 μm, the second threshold is 0.15.

[0271] The results of the evaluation are shown in the "Evaluation B-1" and "Evaluation B-2" columns of FIG. 48. In the "Evaluation B-1" column, "OK" indicates that the absolute value of (S1-S2) / S2 was 0.15 or less in all the through holes 25 of the deposition mask 20, and "NG" indicates that (S1-S2) / S2 exceeded 0.15 in at least some of the through holes 25. In the "Evaluation B-2" column, "OK" indicates that the absolute value of (S1-S2) / S2 was 0.15 or less in all the through holes 25 of the deposition mask 20, and "NG" indicates that (S1-S2) / S2 was less than -0.15 in at least some of the through holes 25. Therefore, when the above-mentioned enlarged through holes are generated, NG is likely to appear in the evaluation B-1, and when the above-mentioned reduced through holes are generated, NG is likely to appear in the evaluation B-2. The number of through holes 25 evaluated per one deposition mask 20 was more than 25 million.

[0272] The size of the through hole 25 generally becomes smaller as the pixel density of the display device increases. For example, in the case of a WQHD display device for a smartphone, the pixel density is about 500 ppi, and the diameter of the through hole 25 is about 30 μm. In the case of a UHD display device for a smartphone, the pixel density is about 800 ppi, and the diameter of the through hole 25 is about 20 μm.

[0273] In order to form the through-holes 25 having small dimensions in the metal plate 64 with high accuracy, it is preferable that the thickness of the metal plate 64 is small. For example, the thickness of the metal plate 64 of the deposition mask 20 for producing a smartphone display device having a pixel density of about 500 ppi is preferably 20 μm or less. In contrast, the thickness of the metal plate 64 of the deposition mask 20 for producing a smartphone display device having a pixel density of about 800 ppi is preferably 15 μm or less.

[0274] The results of Evaluations A-1 and A-2, and Evaluations B-1 and B-2 will be explained below.

[0275] As shown in Figure 48, sample 81 had a volume of 1 mm 3Regarding the particles contained per mask, the first to sixth masks, the eighth to twelfth masks, the sixteenth masks, the seventeenth masks, and the twenty-first to twenty-fifth masks, in which the number of particles having a circle equivalent diameter of 1 μm or more is 50 or more and 3000 or less, were rated as OK in the evaluation A-1. On the other hand, the thirteenth to fifteenth masks, in which the number of particles having a circle equivalent diameter of 1 μm or more exceeds 3000, were rated as NG in the evaluation A-1. From this, it can be said that the above-mentioned condition (1) is a useful judgment condition for suppressing the formation of enlarged through holes.

[0276] As shown in Figure 48, sample 81 had a volume of 1 mm 3 Regarding the particles contained per mask, the first to sixth masks, the eighth to thirteenth masks, the sixteenth masks, the seventeenth masks, and the twenty-first to twenty-fifth masks, in which the number of particles having a circle equivalent diameter of 3 μm or more per mask is 50 or less, were rated as OK in the evaluation A-2. On the other hand, the fourteenth and fifteenth masks, in which the number of particles having a circle equivalent diameter of 3 μm or more per mask is more than 50, were rated as NG in the evaluation A-2. From this, it can be said that the above-mentioned condition (2) is a useful judgment condition for suppressing the formation of reduced through holes.

[0277] As described above, when the seventh winding metal plate 64 was used, the resist film peeled off from the metal plate 64 during the etching process for forming the through-holes 25 by etching the metal plate 64. For this reason, it was not possible to manufacture the deposition mask 20 from the seventh winding metal plate 64. As shown in FIG. 48, the deposition mask 20 of the sample 81 with a volume of 1 mm 3 The number of particles having an equivalent circle diameter of 1 μm or more contained per unit area was less than 50. From this, it can be said that the item in the above condition (1) that "the number of particles having an equivalent circle diameter of 1 μm or more is 50 or more" is a useful judgment criterion for suppressing peeling of the resist film.

[0278] As shown in Figure 48, sample 81 had a volume of 1 mm 3With regard to the particles contained per mask, the first mask, the fourth mask to the sixth mask, the eighth mask to the twelfth mask, the twenty-fourth mask, and the twenty-fifth mask, in which the number of particles having a circle equivalent diameter of 1 μm or more is 1000 or less, were rated as OK in the evaluation B-1. On the other hand, the second mask, the third mask, the thirteenth mask to the seventeenth mask, and the twenty-first mask to the twenty-third mask, in which the number of particles having a circle equivalent diameter of 1 μm or more and less than 3 μm exceeds 1000, were rated as NG in the evaluation B-1. From this, it can be said that the above-mentioned condition (3) is a useful judgment condition for more reliably suppressing the formation of enlarged through holes.

[0279] As shown in Figure 48, sample 81 had a volume of 1 mm 3 Regarding the particles contained per mask, the first mask, the fourth mask to the sixth mask, the eighth mask to the twelfth mask, the twenty-first mask, the twenty-second mask, the twenty-fourth mask, and the twenty-fifth mask, in which the number of particles having a circle equivalent diameter of 3 μm or more is 20 or less, were rated as OK in B-2. On the other hand, the second mask, the third mask, the thirteenth mask to the seventeenth mask, and the twenty-third mask, in which the number of particles having a circle equivalent diameter of 3 μm or more is more than 20, were rated as NG in B-2. From this, it can be said that the above-mentioned condition (4) is a useful judgment condition for more reliably suppressing the formation of reduced through holes.

[0280] In the above-mentioned Examples 1 to 6, 8 to 17, and 21 to 25, the observation results of particles contained in the sample taken from the first end 17a of the deposition mask 20 are shown. It is expected that the same observation results as these observation results will be obtained when observing particles contained in the sample taken from the metal plate 64 of the first to sixth windings, the eighth to seventeenth windings, and the twenty-first to twenty-fifth windings. In the first-side etching process and the second-side etching process, the region of the metal plate 64 corresponding to the first end 17a is covered with the first resist film 65a and the second resist film 65b. For this reason, the state of the metal plate 64 constituting the first end 17a is considered to be the same as the state of the metal plate 64 when it constituted the winding in terms of particle distribution.

[0281] (Supplementary Evaluation 1) As in Example 1, iron, nickel, and other raw materials were prepared so that the ratio of iron and nickel to the total raw materials was about 64% by weight and about 36% by weight, respectively. Then, each raw material was crushed as necessary, and then the first melting step, the first surface treatment step, the second melting step, and the second surface treatment step were carried out to produce a base material. Then, the base material was subjected to a rolling step, an annealing step, and a slitting step to produce an 18th roll having a thickness of 20 μm and in which a metal plate 64 was wound into a roll shape.

[0282] Next, a square sample 81 with a side length K1 of 60 mm was cut out at a location located 1 m from the tip of the metal plate of the 18th winding body in the longitudinal direction of the metal plate. Similarly, square samples 81 with a side length K1 of 60 mm were cut out at locations located 100 m, 200 m, 300 m, and 400 m from the tip of the metal plate of the 18th winding body in the longitudinal direction of the metal plate. After samples 81 were cut out at five locations on the metal plate of the 18th winding body in this manner, the particles contained in each sample 81 were observed using an SEM in the same manner as in Example 1 above, and the particles in the sample 81 were observed to have a volume of 1 mm 3 The number of particles contained per unit area and the equivalent circle diameter of each particle were calculated. Furthermore, the composition of particles having an equivalent circle diameter of 1 μm or more was analyzed using an EDX device in the same manner as in Example 1 above. The results are shown in Figures 50 and 51.

[0283] As shown in Figure 50, the cut-out sample 81 has a volume of 1 mm 3 The number of particles with a circular equivalent diameter of 1 μm or more per sample was distributed within the range of 585 to 859, with the average value being 689.0, and the distribution range being 274. The distribution range is the number of particles per 1 mm2 of the sample 81 cut out from five locations. 3 The difference between the maximum and minimum number of particles with a circular equivalent diameter of 1 μm or more per unit area is the difference between the maximum and minimum number of particles with a circular equivalent diameter of 1 μm or more per unit area. The value obtained by dividing the distribution range by the average value was 0.398. Therefore, the distribution range of 81 samples cut out from five locations with a volume of 1 mm 3The number of particles with a circular equivalent diameter of 1 μm or more per unit area was within the range of the midpoint between the maximum and minimum values ​​±20%. The ratio of the maximum value to the minimum value was 1.5 or less. From this, it can be said that the volume of sample 81 cut out from a random location of the rolled body was 1 mm 3 If the number of particles with a circular equivalent diameter of 1 μm or more contained in one roll is, for example, Y, then the volume of sample 81 cut out from another part of the same roll is 1 mm 3 It is highly likely that the number of particles having an equivalent circle diameter of 1 μm or more per unit area is less than 1.5×Y.

[0284] Figure 50 shows the volume of sample 81 cut out at five points, 1 mm 3 The number and ratio of particles of each size per unit area are also shown. The first and second ratios showed the same tendency as the total number. The results of particle composition analysis shown in Figure 51 also showed the same tendency as the total number.

[0285] (Supplementary evaluation 2) As in Example 1, iron, nickel, and other raw materials were prepared so that the ratio of iron and nickel to the total raw materials was about 64% by weight and about 36% by weight, respectively. Then, each raw material was crushed as necessary, and then the first melting step, the first surface treatment step, the second melting step, and the second surface treatment step were carried out to produce a base material. Then, the base material was subjected to a rolling step, an annealing step, and a slitting step to produce a 19th roll having a thickness of 20 μm and in which the metal plate 64 was wound into a roll shape.

[0286] 6 to 11 using the metal plate 64 of the 19th winding body in the same manner as in Example 1. In addition, particles contained in each sample 81 taken out from the first end 17a and the second end 17b of the deposition mask 20 were observed using an SEM, and the number of particles per 1 mm of the sample 81 was 1. 3The number of particles contained per unit area and the equivalent circle diameter of each particle were calculated. The results are shown in Figure 52. Furthermore, in the same manner as in Example 1 above, the composition of particles having an equivalent circle diameter of 1 μm or more was analyzed using an EDX device. The results are shown in Figure 53.

[0287] As shown in Figure 52, the cut-out sample 81 has a volume of 1 mm 3 The number of particles having a circle equivalent diameter of 1 μm or more per unit area was distributed within a range of 833 to 1158, with an average value of 995.5 and a distribution range of 325. The distribution range is defined as the number of particles per unit area within a volume of 1 mm2 of sample 81 cut out at first end 17a. 3 The number of particles having a circle equivalent diameter of 1 μm or more contained per 1 mm 3 The difference between the number of particles having a circle-equivalent diameter of 1 μm or more per unit area is the difference between the number of particles having a circle-equivalent diameter of 1 μm or more per unit area. The value obtained by dividing the distribution range by the average value was 0.326. 3 The number of particles having a circle equivalent diameter of 1 μm or more per unit area was within the range of the midpoint between the maximum and minimum values ​​±20%. The ratio of the number of particles at the first end 17a to the number of particles at the second end 17b was 1.5 or less. From this, it can be concluded that the volume of sample 81 cut out from an arbitrary point of the deposition mask is 1 mm 3 When the number of particles having a circle equivalent diameter of 1 μm or more contained per unit area is, for example, Z, the volume of sample 81 cut out from another part of the same deposition mask is 1 mm 3 It is highly likely that the number of particles having an equivalent circle diameter of 1 μm or more per unit area is less than 1.5 × Z.

[0288] FIG. 52 shows a cross-sectional view of a sample 81 cut out from the first end 17a and the second end 17b of the deposition mask 20, with a volume of 1 mm 3 The number and ratio of particles of each size per unit area are also shown. The first and second ratios showed similar trends to those for the total number. The results of particle composition analysis shown in Figure 53 also showed similar trends to those for the total number.

Claims

[Claim 1] A metal plate used for manufacturing a deposition mask, the metal plate including a first surface and a second surface located opposite to the first surface, the metal plate including iron and nickel, The particle includes an element other than iron and nickel as a main component, In a sample including the first surface and the second surface of the metal plate, the following conditions (1) and (2) are satisfied: (1) The volume of the sample is 1 mm ３ the number of the particles having an equivalent circle diameter of 1 μm or more contained per unit area is 50 to 3,000; (2) The volume of the sample is 1 mm ３ the number of particles having an equivalent circle diameter of 3 μm or more contained per unit area is 50 or less; metal plate.

Images