Metal plate for producing vapor deposition masks

Abstract

To provide a metal plate suitable for producing vapor deposition masks.SOLUTION: When a plurality of samples of a metal plate are evaluated, a correlation coefficient in a case where a correction distance is 0.2 μm is higher than a correlation coefficient in a case where the correction distance is 0.1 μm, and is also higher than a correlation coefficient in a case where the correction distance is 0.3 μm; and when a plurality of samples of the metal plate are evaluated, a pit-corrected volume density in a case where the correction distance is 0.2 μm is equal to or less than 12000 μm3 / mm2.SELECTED DRAWING: Figure 14

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a metal plate for manufacturing a vapor deposition mask.

Background Art

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

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

[0004] As a method for manufacturing an evaporation mask, a method of forming through holes in a metal plate by etching using photolithography technology is known. For example, first, a first resist pattern is formed on the first surface of the metal plate by exposure and development processing, and a second resist pattern is formed on the second surface of the metal plate by exposure and development processing. Next, the region of the first surface of the metal plate that is not covered by the first resist pattern is etched to form a first recess on the first surface of the metal plate. Thereafter, the region of the second surface of the metal plate that is not covered by the second resist pattern is etched to form a second recess on the second surface of the metal plate. At this time, by performing etching so that the first recess and the second recess communicate with each other, a through hole penetrating the metal plate can be formed. The metal plate for manufacturing the evaporation mask is manufactured, for example, by rolling a base material made of an iron alloy containing nickel.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] An embodiment of the present disclosure aims to provide a metal plate suitable for manufacturing an evaporation mask.

[0007] An embodiment of the present disclosure is a metal plate for manufacturing an evaporation mask, when a plurality of samples of the metal plate are evaluated by the following evaluation method, the correlation coefficient when the correction distance is 0.2 μm is higher than the correlation coefficient when the correction distance is 0.1 μm, and is also higher than the correlation coefficient when the correction distance is 0.3 μm, when a plurality of samples of the metal plate are evaluated by the following evaluation method, the depression correction volume density when the correction distance is 0.2 μm is 12000 μm 3 / mm 2 or less, the evaluation method is A step of calculating a correlation coefficient between a plurality of dent-corrected volume densities calculated based on a plurality of correction distances and a standard deviation of the width of the rib portion, the rib portion is a portion of the surface of the metal plate that is located between a plurality of recesses formed by etching the metal plate and remains unetched; the metal plate has a plurality of depressions located on a surface of the metal plate; The surface is 0.1 mm 2 a test area having an area of ​​at least one of the plurality of recesses, each of the plurality of dent-corrected volume densities is calculated by dividing a dent-corrected volume corresponding to each of the plurality of corrected distances by an area of ​​the inspection region; the dent correction volume is a sum of volumes of portions of the part of the plurality of dents located in the inspection area that are apart from the surface in a thickness direction of the metal plate by the correction distance or more, The volume is calculated based on a result of measuring the depth of the part of the plurality of recesses by a laser microscope, the metal plate.

[0008] According to an embodiment of the present disclosure, a metal plate suitable for manufacturing a deposition mask can be efficiently obtained. [Brief description of the drawings]

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings attached to this specification, for the convenience of illustration and easier understanding, the scale, the aspect ratio of the vertical and horizontal dimensions, etc. are appropriately changed and exaggerated from those of the actual object.

[0011] Note that the embodiments of the present disclosure can be combined with other embodiments and modification examples within a range where no contradiction occurs. Also, other embodiments can be combined with each other, and other embodiments and modification examples can be combined with each other within a range where no contradiction occurs. Further, modification examples can be combined with each other within a range where no contradiction occurs.

[0012] Also, in the embodiments of the present disclosure, when disclosing a plurality of steps regarding a method such as a manufacturing method, other steps not disclosed may be implemented between the disclosed steps. Also, the order of the disclosed steps is arbitrary within a range where no contradiction occurs.

[0013] Also, the problems to be solved by the embodiments of the present disclosure will be described.

[0014] On the surface of the rolled metal plate, depressions such as oil pits may be formed. The state of the depressions on the surface of the metal plate affects the dimensional accuracy and positional accuracy of the through holes formed in the metal plate. For example, when the depth of the depressions on the surface of the metal plate increases, the dimensions of the through holes formed in the metal plate become larger than the design values. Therefore, a technique for inspecting the state of the depressions on the surface of the metal plate is important.

[0015] As a technique for inspecting undulations such as depressions on the surface of a metal plate, a technique for calculating the arithmetic mean roughness Ra or the maximum height Ry of the surface is known. The arithmetic mean roughness Ra is a value obtained by measuring the position of the surface of the metal plate in the thickness direction (hereinafter also referred to as the height position) at a plurality of points on a predetermined straight line and calculating the average thereof. The maximum height Ry is the difference between the maximum value and the minimum value of the measurement results when the height position of the surface of the metal plate is measured at a plurality of points on a predetermined straight line.

[0016] As a result of intensive research by the inventors of the present application, it has been found that the correlation between the surface undulation index such as the arithmetic mean roughness Ra in the prior art and the dimensional accuracy of the through holes formed in the metal plate is not necessarily high. Therefore, when determining the quality of a metal plate based on the arithmetic mean roughness Ra, it is necessary to make the pass / fail judgment threshold stricter than necessary in order to prevent misjudgment. As a result, the yield of the metal plate decreases.

[0017] An embodiment of the present disclosure aims to provide a metal plate, a method for manufacturing a metal plate, a vapor deposition mask, and a method for manufacturing a vapor deposition mask that can effectively solve such problems.

[0018] FIGS. 1 to 28 are diagrams for explaining an embodiment of the present disclosure. In the following embodiments and modifications thereof, a method for manufacturing a vapor deposition mask used for patterning an organic material on a substrate in a desired pattern when manufacturing an organic EL display device will be described as an example. However, the embodiments of the present disclosure can be applied to vapor deposition masks used for various applications without being limited to such applications.

[0019] In this specification, the terms "plate", "sheet", and "film" are not distinguished from each other based only on the difference in name. For example, the "plate" is a concept including members that can be called sheets or films.

[0020] Further, the "plate surface (sheet surface, film surface)" refers to the surface that coincides with the planar direction of the target plate-like (sheet-like, film-like) member when the target plate-like (sheet-like, film-like) member is viewed as a whole and globally. Also, the normal direction used for the plate-like (sheet-like, film-like) member refers to the normal direction with respect to the plate surface (sheet surface, film surface) of the member.

[0021] Furthermore, regarding the terms used in this specification to specify the shape, geometric conditions, physical properties, and their degrees, such as "parallel", "orthogonal", "identical", "equivalent", etc., as well as the lengths, angles, and values of physical properties, they shall be interpreted without being restricted to a strict meaning and including a range to the extent that similar functions can be expected.

[0022] First, a vapor deposition apparatus 90 for performing a vapor deposition process of vapor-depositing a vapor deposition material on an object will be described with reference to FIG. 1. As shown in FIG. 1, the vapor deposition apparatus 90 may include a vapor deposition source (for example, crucible 94), a heater 96, and a vapor deposition mask device 10 inside thereof. Further, the vapor deposition apparatus 90 may further include an exhaust means for making the inside of the vapor deposition apparatus 90 a vacuum atmosphere. The crucible 94 accommodates a vapor deposition material 98 such as an organic light-emitting material. The heater 96 heats the crucible 94 to evaporate the vapor deposition material 98 under a vacuum atmosphere. The vapor deposition mask device 10 is arranged to face the crucible 94.

[0023] Hereinafter, the vapor deposition mask device 10 will be described. As shown in FIG. 1, the vapor deposition mask device 10 may include a vapor deposition mask 20 and a frame 15 for supporting the vapor deposition mask 20. The frame 15 supports the vapor deposition mask 20 in a state of pulling it in its surface direction so that the vapor deposition mask 20 does not bend. As shown in FIG. 1, the vapor deposition mask device 10 is arranged in the vapor deposition apparatus 90 such that the vapor deposition mask 20 faces a substrate, for example, an organic EL substrate 92, which is an object to which the vapor deposition material 98 is to be attached. In the following description, among the surfaces of the vapor deposition mask 20, the surface on the organic EL substrate 92 side is referred to as the first surface 20a, and the surface located on the opposite side of the first surface 20a is referred to as the second surface 20b.

[0024] As shown in FIG. 1, the evaporation mask apparatus 10 may include a magnet 93 disposed on the surface of the organic EL substrate 92 opposite to the evaporation mask 20. By providing the magnet 93, the evaporation mask 20 can be attracted toward the magnet 93 by magnetic force, and the evaporation mask 20 can be brought into close contact with the organic EL substrate 92.

[0025] FIG. 3 is a plan view showing the case where the evaporation mask apparatus 10 is viewed from the first surface 20a side of the evaporation mask 20. As shown in FIG. 3, the evaporation mask apparatus 10 may include a plurality of evaporation masks 20. Each evaporation mask 20 may include a pair of long sides 26 and a pair of short sides 27. For example, each evaporation mask 20 may have a rectangular shape. Each evaporation mask 20 may be fixed to the frame 15, for example, by spot welding, at a pair of short sides 27 or a portion in the vicinity thereof.

[0026] The evaporation mask 20 may include a plate-like base material made of metal, in which a plurality of through holes 25 penetrating the evaporation mask 20 are formed. The evaporation material 98 evaporated from the crucible 94 and reaching the evaporation mask apparatus 10 adheres to the organic EL substrate 92 through the through holes 25 of the evaporation mask 20. Thereby, the evaporation material 98 can 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 evaporation mask 20.

[0027] FIG. 2 is a cross-sectional view showing an organic EL display device 100 manufactured using the vapor deposition apparatus 90 of FIG. 1. The organic EL display device 100 includes at least an organic EL substrate 92 and pixels including a vapor deposition material 98 provided in a pattern. Although not shown, the organic EL display device 100 further includes an electrode electrically connected to the pixels including the vapor deposition material 98. The electrode is provided in advance on the organic EL substrate 92, for example, before the vapor deposition material 98 is deposited on the organic EL substrate 92 by a vapor 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 vapor deposition material 98 from the outside. Therefore, it can be said that the organic EL display device 100 in FIG. 2 is an intermediate body of the organic EL display device generated in the intermediate stage of manufacturing the organic EL display device.

[0028] Incidentally, when color display using a plurality of colors is desired, a vapor deposition apparatus 90 equipped with a vapor deposition mask 20 corresponding to each color is prepared, and the organic EL substrate 92 is sequentially loaded into each vapor deposition apparatus 90. Thereby, for example, an organic light-emitting material for red, an organic light-emitting material for green, and an organic light-emitting material for blue can be sequentially deposited on the organic EL substrate 92.

[0029] By the way, the vapor deposition process may be performed inside the vapor deposition apparatus 90 where a high-temperature atmosphere is present. In this case, during the vapor deposition process, the vapor deposition mask 20, the frame 15, and the organic EL substrate 92 held inside the vapor deposition apparatus 90 are also heated. At this time, the vapor deposition mask 20, the frame 15, and the organic EL substrate 92 will exhibit behaviors of dimensional changes based on their respective coefficients of thermal expansion. In this case, if the coefficients of thermal expansion of the vapor deposition mask 20 or the frame 15 and the organic EL substrate 92 are significantly different, misalignment will occur due to the difference in their dimensional changes. As a result, the dimensional accuracy and positional accuracy of the vapor deposition material deposited on the organic EL substrate 92 will deteriorate.

[0030] To solve such problems, it is preferable that the thermal expansion coefficients of the vapor deposition mask 20 and the frame 15 are equal to the thermal expansion coefficient of the organic EL substrate 92. For example, when a glass substrate is used as the organic EL substrate 92, an iron alloy containing nickel can be used as the main material of the vapor deposition mask 20 and the frame 15. For example, an iron alloy containing 30% by mass or more and 54% by mass or less of nickel can be used as the material of the base material constituting the vapor deposition mask 20. Specific examples of the iron alloy containing nickel include an Invar material containing 34% by mass or more and 38% by mass or less of nickel, a Super Invar material containing cobalt in addition to 30% by mass or more and 34% by mass or less of nickel, and a low thermal expansion Fe-Ni-based plating alloy containing 38% by mass or more and 54% by mass or less of nickel.

[0031] In addition, during the vapor deposition process, when the temperatures of the vapor deposition mask 20, the frame 15, and the organic EL substrate 92 do not reach a high temperature, there is no particular need to make the thermal expansion coefficients of the vapor deposition mask 20 and the frame 15 equal 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 the material constituting the vapor 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 called so-called stainless steel can be used. Also, an alloy other than an iron alloy, such as nickel or a nickel-cobalt alloy, may be used.

[0032] Next, the vapor deposition mask 20 will be described in detail. As shown in FIG. 3, the vapor deposition mask 20 may include a pair of ear portions (a first ear portion 17a and a second ear portion 17b) including a pair of short sides 27 of the vapor deposition mask 20, and an intermediate portion 18 located between the pair of ear portions 17a and 17b.

[0033] First, the ear portions 17a and 17b will be described in detail. The ear portions 17a and 17b are the portions of the vapor deposition mask 20 that are fixed to the frame 15. In the present embodiment, the ear portions 17a and 17b are integrally formed with the intermediate portion 18. Note that the ear portions 17a and 17b may be formed of a member different from the intermediate portion 18. In this case, the ear portions 17a and 17b are joined to the intermediate portion 18 by, for example, welding.

[0034] Next, the intermediate portion 18 will be described. The intermediate portion 18 may include at least one effective region 22 in which a through hole 25 extending from the first surface 20a to the second surface 20b is formed, and a peripheral region 23 surrounding the effective region 22. The effective region 22 is a region of the vapor deposition mask 20 that faces the display region of the organic EL substrate 92.

[0035] In the example shown in FIG. 3, the intermediate portion 18 includes a plurality of effective regions 22 arranged at a predetermined interval along the long side 26 of the vapor deposition mask 20. One effective region 22 corresponds to the display region of one organic EL display device 100. Therefore, according to the vapor deposition mask device 10 shown in FIG. 1, multi-sided vapor deposition of the organic EL display device 100 is possible. Note that one effective region 22 may correspond to a plurality of display regions.

[0036] As shown in FIG. 3, the effective region 22 may have, for example, a substantially rectangular shape in plan view, and more precisely, a substantially rectangular contour in plan view. Although not shown, each effective region 22 can have various shaped contours according to the shape of the display region of the organic EL substrate 92. For example, each effective region 22 may have a circular contour. Also, each effective region 22 may have the same contour as the outer shape of a display device such as a smartphone.

[0037] Hereinafter, the active region 22 will be described in detail. FIG. 4 is a plan view showing an enlarged view of the active region 22 from the second surface 20b side of the vapor deposition mask 20. As shown in FIG. 4, in the illustrated example, the plurality of through holes 25 formed in each active region 22 may be arranged at a predetermined pitch along two directions orthogonal to each other in the active region 22. An example of the through hole 25 will be described in more detail mainly with reference to FIGS. 5 to 7. FIGS. 5 to 7 are cross-sectional views along the V-V direction to the VII-VII direction of the active region 22 in FIG. 4, respectively.

[0038] As shown in FIGS. 5 to 7, the plurality of through holes 25 penetrate from the first surface 20a on one side along the normal direction N of the vapor deposition mask 20 to the second surface 20b on the other side along the normal direction N of the vapor deposition mask 20. In the illustrated example, as will be described in detail later, a first recess 30 is formed by etching on the first surface 21a of the metal plate 21 on one side in the normal direction N of the vapor deposition mask 20, and a second recess 35 is formed on the second surface 21b of the metal plate 21 on the other side in the normal direction N of the vapor deposition mask 20. The first recess 30 is connected to the second recess 35, and thus the second recess 35 and the first recess 30 are formed to communicate with each other. The through hole 25 is constituted by the second recess 35 and the first recess 30 connected to the second recess 35.

[0039] As shown in FIGS. 5 to 7, from the side of the second surface 20b of the vapor deposition mask 20 toward the side of the first surface 20a, the opening area of each second recess 35 in the cross section along the plate surface of the vapor deposition mask 20 at each position along the normal direction N of the vapor deposition mask 20 gradually decreases. Similarly, the opening area of each first recess 30 in the cross section along the plate surface of the vapor deposition mask 20 at each position along the normal direction N of the vapor deposition mask 20 gradually decreases from the side of the first surface 20a of the vapor deposition mask 20 toward the side of the second surface 20b.

[0040] As shown in FIGS. 5 to 7, the wall surface 31 of the first recess 30 and the wall surface 36 of the second recess 35 are connected via a circumferential connecting portion 41. The connecting portion 41 is defined by the ridge line of the protruding portion where the wall surface 31 of the first recess 30 inclined with respect to the normal direction N of the vapor deposition mask 20 and the wall surface 36 of the second recess 35 inclined with respect to the normal direction N of the vapor deposition mask 20 merge. And the connecting portion 41 defines a through portion 42 where the opening area of the through hole 25 is minimized in the plan view of the vapor deposition mask 20.

[0041] As shown in FIGS. 5 to 7, on the other side surface along the normal direction N of the vapor deposition mask 20, that is, on the first surface 20a of the vapor deposition mask 20, two adjacent through holes 25 are separated from each other along the plate surface of the vapor deposition mask 20. That is, when the first recess 30 is formed by etching the metal plate 21 from the first surface 21a side of the metal plate 21 corresponding to the first surface 20a of the vapor deposition mask 20 as in the manufacturing method described later, the first surface 21a of the metal plate 21 remains between two adjacent first recesses 30.

[0042] Similarly, as shown in FIGS. 5 to 7, on one side along the normal direction N of the vapor deposition mask 20, that is, on the side of the second surface 20b of the vapor deposition mask 20, two adjacent second recesses 35 are spaced apart from each other along the plate surface of the vapor deposition mask 20. That is, the second surface 21b of the metal plate 21 remains between two adjacent second recesses 35. In the following description, the portion of the effective region 22 of the second surface 21b of the metal plate 21 that remains without being etched is also referred to as the top portion 43. By manufacturing the vapor deposition mask 20 so that such a top portion 43 remains, the vapor deposition mask 20 can be given sufficient strength. Thereby, for example, it is possible to suppress the vapor deposition mask 20 from being damaged during transportation or the like. If the width β of the top portion 43 is too large, a shadow may occur in the vapor deposition process, which may reduce the utilization efficiency of the vapor deposition material 98. Therefore, it is preferable that the vapor deposition mask 20 is manufactured so that the width β of the top portion 43 does not become excessively large. For example, it is preferable that the width β of the top portion 43 is 2 μm or less. Note that the width β of the top portion 43 generally varies depending on the direction in which the vapor deposition mask 20 is cut. For example, the widths β of the top portions 43 shown in FIGS. 5 to 7 may be different from each other. In this case, the vapor deposition mask 20 may be configured such that the width β of the top portion 43 is 2 μm or less when the vapor deposition mask 20 is cut in any direction. A shadow is a phenomenon in which the adhesion of the vapor deposition material to the region overlapping the through hole of the vapor deposition mask 20 in the vapor deposition object such as the organic EL substrate 92 is inhibited by the second surface 20b and the wall surface of the vapor deposition mask 20.

[0043] When the vapor deposition mask device 10 is accommodated in the vapor deposition device 90 as shown in FIG. 1, as shown by the two-dot chain line in FIG. 5, the first surface 20a of the vapor deposition mask 20 faces the organic EL substrate 92, and the second surface 20b of the vapor deposition mask 20 is located on the side of the crucible 94 holding the vapor deposition material 98. Therefore, the vapor deposition material 98 adheres to the organic EL substrate 92 through the second recess 35 whose opening area gradually decreases. As shown by the arrow from the second surface 20b side to the first surface 20a in FIG. 5, the vapor deposition material 98 not only moves along the normal direction N of the organic EL substrate 92 from the crucible 94 toward the organic EL substrate 92, but may also move 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 vapor deposition mask 20 is large, the vapor deposition material 98 moving obliquely is likely to be caught by the top portion 43, the wall surface 36 of the second recess 35, or the wall surface 31 of the first recess 30. As a result, the ratio of the vapor deposition material 98 that cannot pass through the through hole 25 increases. Therefore, in order to increase the utilization efficiency of the vapor deposition material 98, it is considered preferable to reduce the thickness t of the vapor 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, as the metal plate 21 for constituting the vapor deposition mask 20, it can be said that it is preferable to use a metal plate 21 with as small a thickness t as possible within the range where the strength of the vapor deposition mask 20 can be ensured. Considering this point, in the present embodiment, the thickness t of the vapor deposition mask 20 is, for example, 30 μm or less, preferably 25 μm or less, and more preferably 20 μm or less. The thickness t of the vapor deposition mask 20 may be 18 μm or less, or may be 15 μm or less. On the other hand, if the thickness of the vapor deposition mask 20 becomes too small, the strength of the vapor deposition mask 20 decreases, and the vapor deposition mask 20 is likely to be damaged or deformed. Considering this point, the thickness t of the vapor deposition mask 20 may be 5 μm or more, may be 7 μm or more, may be 10 μm or more, may be 13 μm or more, or may be 15 μm or more. The thickness t is the thickness of the peripheral region 23, that is, the thickness of the portion of the vapor 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 21.

[0044] The range of the thickness t of the vapor deposition mask 20 may be determined by any combination of any one of the plurality of candidate upper limit values described above and any one of the plurality of candidate lower limit values described above. For example, the thickness t of the vapor deposition mask 20 may be 5 μm or more and 30 μm or less, may be 7 μm or more and 25 μm or less, may be 10 μm or more and 20 μm or less, or may be 13 μm or more and 18 μm or less. Further, the range of the thickness t of the vapor deposition mask 20 may be determined by any combination of any two of the plurality of candidate upper limit values described above. For example, the thickness t of the vapor deposition mask 20 may be 25 μm or more and 300 μm or less. Further, the range of the thickness t of the vapor deposition mask 20 may be determined by any combination of any two of the plurality of candidate lower limit values described above. For example, the thickness t of the vapor deposition mask 20 may be 5 μm or more and 7 μm or less.

[0045] In FIG. 5, the minimum angle formed by a straight line L1 passing through the connection portion 41 that becomes the portion having the minimum opening area of the through hole 25 and any other position on the wall surface 36 of the second recess 35 with respect to the normal direction N of the vapor deposition mask 20 is represented by the symbol θ1. In order to allow the vapor deposition material 98 moving obliquely to reach the organic EL substrate 92 as much as possible without reaching the wall surface 36, it is advantageous to increase the angle θ1. In increasing the angle θ1, in addition to reducing the thickness t of the vapor deposition mask 20, it is also effective to reduce the width β of the top portion 43 described above.

[0046] In FIG. 7, the symbol α represents the width of the portion (hereinafter also referred to as the rib portion) that remains without being etched in the effective region 22 of the first surface 21a of the metal plate 21. The width α of the rib portion and the dimension r2 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 r2 of the through portion 42 is 10 μm or more and 60 μm or less.

[0047] The width α of the rib portion may be 10 μm or more, may be 15 μm or more, or may be 20 μm or more. Also, the width α of the rib portion may be 35 μm or less, may be 30 μm or less, or may be 25 μm or less. The range of the width α of the rib portion may be determined by a combination of any one of the plurality of candidate upper limit values described above and any one of the plurality of candidate lower limit values described above. For example, the width α of the rib portion may be 10 μm or more and 35 μm or less, may be 15 μm or more and 30 μm or less, or may be 20 μm or more and 25 μm or less. Also, the range of the width α of the rib portion may be determined by a combination of any two of the plurality of candidate upper limit values described above. For example, the width α of the rib portion may be 35 μm or more and 40 μm or less. Also, the range of the width α of the rib portion may be determined by a combination of any two of the plurality of candidate lower limit values described above. For example, the width α of the rib portion may be 5 μm or more and 10 μm or less.

[0048] The dimension r2 of the through portion 42 may be 15 μm or more, may be 20 μm or more, may be 25 μm or more, or may be 30 μm or more. Also, the lower limit of the dimension r2 of the through portion 42 may be smaller than the above-described 10 μm. For example, the dimension r of the through portion 42 may be 5 μm or more. Further, the dimension r2 of the through portion 42 may be 55 μm or less, may be 50 μm or less, may be 45 μm or less, may be 40 μm or less, or may be 35 μm or less. The range of the dimension r2 of the through portion 42 may be determined by a combination of any one of the above-described plurality of candidate upper limit values and any one of the above-described plurality of candidate lower limit values. For example, the dimension r2 of the through portion 42 may be 15 μm or more and 55 μm or less, may be 20 μm or more and 50 μm or less, may be 25 μm or more and 45 μm or less, may be 30 μm or more and 40 μm or less, or may be 30 μm or more and 35 μm or less. Also, the range of the dimension r2 of the through portion 42 may be determined by a combination of any two of the above-described plurality of candidate upper limit values. For example, the dimension r2 of the through portion 42 may be 55 μm or more and 60 μm or less. Further, the range of the dimension r2 of the through portion 42 may be determined by a combination of any two of the above-described plurality of candidate lower limit values. For example, the dimension r2 of the through portion 42 may be 5 μm or more and 10 μm or less.

[0049] In FIGS. 4 to 7, an example is shown in which the second surface 21b of the metal plate 21 remains between two adjacent second recesses 35, but the present invention is not limited thereto. As shown in FIG. 8, depending on the location, etching may be performed so that two adjacent second recesses 35 are connected. That is, there may be a location where the second surface 21b of the metal plate 21 does not remain between two adjacent second recesses 35. Also, although not shown, etching may be performed so that two adjacent second recesses 35 are connected over the entire area of the second surface 21b. FIG. 9 is a cross-sectional view taken along the IX-IX direction of the effective region 22 of FIG. 8.

[0050] Although not limited, the vapor deposition mask 20 according to the present embodiment is particularly effective when manufacturing an organic EL display device having a pixel density of 450 ppi or more. Hereinafter, with reference to FIG. 10, an example of the dimensions of the vapor deposition mask 20 required for manufacturing an organic EL display device having such a high pixel density will be described. FIG. 10 is a cross-sectional view showing an enlarged view of the through hole 25 of the vapor deposition mask 20 shown in FIG. 5 and a region in the vicinity thereof.

[0051] In FIG. 10, as a parameter related to the shape of the through hole 25, the distance in the direction along the normal direction N of the vapor deposition mask 20 from the first surface 20a of the vapor deposition mask 20 to the connection portion 41, that is, the height of the wall surface 31 of the first recess 30 is represented by the symbol r1. Further, the dimension of the first recess 30 at the portion where the first recess 30 is connected to the second recess 35, that is, the dimension of the through portion 42 is represented by the symbol r2. Also in FIG. 10, the angle formed by the straight line L2 connecting the connection portion 41 and the leading edge of the first recess 30 on the first surface 21a of the metal plate 21 with respect to the normal direction N of the metal plate 21 is represented by the symbol θ2.

[0052] When manufacturing an organic EL display device having a pixel density of 450 ppi or more, the dimension r2 of the through portion 42 is preferably set to 10 μm or more and 60 μm or less. Thereby, it is possible to provide a vapor deposition mask 20 capable of manufacturing an organic EL display device having a high pixel density. Preferably, the height r1 of the wall surface 31 of the first recess 30 is set to 6 μm or less.

[0053] Next, the above-described angle θ2 shown in FIG. 10 will be described. The angle θ2 corresponds to the maximum value of the inclination angle of the vapor deposition material 98 that flies while being inclined with respect to the normal direction N of the metal plate 21 and passes through the through-hole 42 in the vicinity of the connection portion 41 and can reach the organic EL substrate 92. This is because the vapor deposition material 98 that flies through the connection portion 41 at an inclination angle larger than the angle θ2 adheres to the wall surface 31 of the first recess 30 before reaching the organic EL substrate 92. Therefore, by reducing the angle θ2, it is possible to suppress the vapor deposition material 98 that flies at a large inclination angle and passes through the through-hole 42 from adhering to the organic EL substrate 92, and thereby suppress the vapor deposition material 98 from adhering to a portion outside the portion of the organic EL substrate 92 that overlaps the through-hole 42. That is, reducing the angle θ2 leads to suppression of variations in the area and thickness of the vapor deposition material 98 adhering to the organic EL substrate 92. From such a viewpoint, for example, the through-hole 25 is formed such that the angle θ2 is 45 degrees or less. In FIG. 10, an example is shown in which the dimension of the first recess 30 in the first surface 21a, that is, the opening dimension of the through-hole 25 in the first surface 21a, is larger than the dimension r2 of the first recess 30 in the connection portion 41. That is, an example in which the value of the angle θ2 is a positive value is shown. However, although not shown, the dimension r2 of the first recess 30 in the connection portion 41 may be larger than the dimension of the first recess 30 in the first surface 21a. That is, the value of the angle θ2 may be a negative value.

[0054] Next, a method for manufacturing the vapor deposition mask 20 will be described.

[0055] First, a method for manufacturing a metal plate used for manufacturing the vapor deposition mask will be described. In the present embodiment, an example in which the metal plate is made of a rolled material of an iron alloy containing nickel will be described. The rolled material may have a thickness of 30 μm or less. Further, the rolled material may contain 30 mass% or more and 38 mass% or less of nickel, 0 mass% or more and 6 mass% or less of cobalt, the balance being iron, and inevitable impurities.

[0056] First, prepare iron, nickel, and other raw materials. For example, prepare each raw material such that the ratio of iron and the ratio of nickel to the total raw materials are approximately 64% by weight and approximately 36% by weight, respectively. Subsequently, after pulverizing each raw material as necessary, perform a melting process of melting each raw material in a melting furnace. For example, utilize gas discharge such as arc discharge to melt and mix each raw material. Thereby, a base material for a metal plate can be obtained.

[0057] The temperature during melting is set according to the raw materials, but is, for example, 1500 °C or higher. The melting process may include a process of introducing aluminum, manganese, silicon, etc. into the melting furnace for deoxidation, dehydration, denitrification, etc. Further, the melting process may be carried out in a low-pressure state lower than atmospheric pressure under an atmosphere of an inert gas such as argon gas.

[0058] After taking out the base material from the melting furnace, a grinding process of scraping the surface of the base material may be performed. Thereby, a film of oxides such as scale can be removed. The specific grinding method is not particularly limited, but for example, a so-called grinding method of rotating a grinding wheel to scrape the surface of the base material, or a so-called pushing method of pushing the base material into a cutting tool to scrape the surface of the base material can be adopted. The grinding process may be carried out so that the thickness of the base material becomes uniform.

[0059] Subsequently, as shown in FIG. 11, perform a rolling process of rolling a base material 60 composed of an iron alloy containing nickel. For example, convey it while applying a tensile stress in the direction indicated by arrow D1 toward a rolling device 66 including a pair of rolling rolls 66a, 66b (work rolls). The base material 60 that has reached between the pair of rolling rolls 66a, 66b is rolled by the pair of rolling rolls 66a, 66b. As a result, the thickness of the base material 60 is reduced and it is stretched along the conveyance direction. Thereby, a metal plate 64 with a thickness T0 can be obtained. As shown in FIG. 11, a wound body 62 may be formed by winding the metal plate 64 around a core 61.

[0060] Note that FIG. 11 only 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 is processed at a temperature equal to or higher than the temperature at which the crystal arrangement of the ferroalloy constituting the base material 60 changes, or a cold rolling process in which the base material is processed at a temperature equal to or lower than the temperature at which the crystal arrangement of the ferroalloy changes. Also, the direction in which the base material 60 or the metal plate 64 passes between the pair of rolling rolls 66a and 66b is not limited to one direction. For example, in FIGS. 11 and 12, the base material 60 or the metal plate 64 may be gradually rolled by repeatedly passing it between the pair of rolling rolls 66a and 66b in the direction from the left side to the right side of the paper surface and in the direction from the right side to the left side of the paper surface.

[0061] In the rolling process, the surface roughness of the metal plate 64 can be adjusted by adjusting the diameters of the rolling rolls 66a and 66b that contact the base material 60. For example, by reducing the diameters of the rolling rolls 66a and 66b, the volume of the depressions described below that exist on the surface of the metal plate 64 can be reduced. Thereby, for example, the depression correction volume density described below can be made 15000 μm 3 / mm 2 or less.

[0062] The diameter of the rolling roll is preferably 28 mm or more. The diameter of the rolling roll may be 40 mm or more, or may be 50 mm or more. Also, the diameter of the rolling roll is preferably 150 mm or less. The diameter of the rolling roll may be 120 mm or less, may be 100 mm, or may be 80 mm or less. The range of the diameter of the rolling roll may be determined by any combination of any one of a plurality of candidate upper limit values and any one of a plurality of candidate lower limit values. For example, the diameter of the rolling roll may be 28 mm or more and 150 mm or less, or may be 40 mm or more and 120 mm or less. Further, the range of the diameter of the rolling roll may be determined by any combination of any two of the plurality of candidate upper limit values. For example, the diameter of the rolling roll may be 120 mm or more and 150 mm or less. Further, the range of the diameter of the rolling roll may be determined by any combination of any two of the plurality of candidate lower limit values. For example, the diameter of the rolling roll may be 28 mm or more and 40 mm or less. The diameter of the rolling roll is preferably 28 mm or more and 150 mm or less, more preferably 40 mm or more and 120 mm or less, more preferably 50 mm or more and 100 mm or less, and still more preferably 50 mm or more and 80 mm or less.

[0063] In the rolling process, the pressure of the rolling actuator may be adjusted to adjust the shape of the metal plate 64. In addition to the rolling rolls (work rolls) 66a and 66b, the shape of the backup roll may be appropriately adjusted, and the position of the backup roll may be appropriately adjusted in the plate width direction.

[0064] In the rolling process, the rolling speed, that is, the conveyance speed of the base material, may be adjusted. From the viewpoint of making the depression correction volume density smaller, it is preferable to slow down the rolling speed. By slowing down the rolling speed, the amount of coolant such as rolling oil entrained between the base material 60 and the rolling rolls 66a and 66b can be reduced. Thereby, the number, area, etc. of the oil pits formed on the surface of the metal plate 64 can be reduced.

[0065] The rolling speed is preferably 30 m / min or more. The rolling speed may be 50 m / min or more, may be 70 m / min or more, or may be 100 m / min or more. Also, the rolling speed is preferably 200 m / min or less. The rolling speed may be 150 m / min or less, may be 100 m / min or less, or may be 80 m / min or less. The rolling speed may be determined by any combination of any one of a plurality of upper limit candidate values and any one of a plurality of lower limit candidate values. For example, the rolling speed may be 30 m / min or more and 200 m / min or less, or may be 50 m / min or more and 150 m / min or less. Also, the range of the rolling speed may be determined by any combination of any two of a plurality of upper limit candidate values. For example, the rolling speed may be 150 m / min or more and 200 m / min or less, or may be 100 m / min or more and 150 m / min or less. Also, the range of the rolling speed may be determined by any combination of any two of a plurality of lower limit candidate values. For example, the range of the rolling speed may be 30 m / min or more and 50 m / min or less, or may be 50 m / min or more and 70 m / min or less. The rolling speed is preferably 30 m / min or more and 200 m / min or less, more preferably 30 m / min or more and 150 m / min or less, more preferably 30 m / min or more and 100 m / min or less, and even more preferably 30 m / min or more and 80 m / min or less.

[0066] In the cold rolling process, a coolant such as kerosene or neat oil may be supplied between the base material 60 and the rolling rolls 66a, 66b. Thereby, the temperature of the base material can be controlled. From the viewpoint of making the depression correction volume density smaller, it is preferable to reduce the supply amount of the coolant.

[0067] Also, by appropriately selecting the coolant, it is also possible to adjust the number, area, etc. of oil pits and rolling streaks formed on the surface of the metal plate 64. For example, neat oil can be used as the coolant. Neat oil has the property that the increase in viscosity during rolling is unlikely to occur. Therefore, by using neat oil as the coolant, the amount of coolant entrained between the base material 60 and the rolling rolls 66a, 66b can be reduced. Thereby, it is possible to suppress the formation of oil pits on the surface of the metal plate 64.

[0068] Also, by appropriately selecting the surface roughness of the rolling rolls, it is also possible to adjust the number, area, etc. of oil pits and rolling streaks formed on the surface of the metal plate 64. For example, by reducing the surface roughness Ra of the rolling rolls, it is possible to suppress the formation of rolling streaks on the surface of the metal plate 64. The surface roughness Ra of the rolling rolls is preferably 0.2 μm or less. The surface roughness Ra of the rolling rolls may be 0.15 μm or less, may be 0.1 μm or less, or may be 0.05 μm or less. The surface roughness Rz of the rolling rolls is preferably 2.0 μm or less. The surface roughness Rx of the rolling rolls may be 1.5 μm or less, may be 1.0 μm or less, or may be 0.5 μm or less. Also, the surface roughness Rz of the rolling rolls is preferably 2.0 μm or less. The surface roughness Rz of the rolling rolls may be 1.5 μm or less, may be 1.0 μm or less, or may be 0.5 μm or less. The surface roughness Ra and Rz are measured based on JIS B 0601:2013.

[0069] Also, an analysis step of analyzing the quality and characteristics of the base material 60 or the metal plate 64 before and after the rolling process or during the rolling process may be performed. For example, the composition may be analyzed by irradiating the base material 60 or the metal plate 64 with fluorescent X-rays. Also, the thermal expansion amount of the base material 60 or the metal plate 64 may be measured by thermomechanical analysis (TMA: Thermomechanical Analysis).

[0070] Thereafter, in order to remove the residual stress accumulated in the metal plate 64 by rolling, as shown in FIG. 12, an annealing process may be performed to anneal the metal plate 64 using an annealing device 67. The annealing process may be performed while pulling the metal plate 64 in the transport direction (longitudinal direction), as shown in FIG. 12. That is, the annealing process may be performed as continuous annealing while transporting, rather than so-called batch annealing. In this case, it is preferable to set the temperature and transport speed so as to suppress deformation such as buckling and warping in the metal plate 64. By performing the annealing process, a metal plate 64 with some of the residual strain removed can be obtained. In FIG. 12, an example is shown in which the metal plate 64 is transported in the horizontal direction during the annealing process, but it is not limited to this, and the metal plate 64 may be transported in other directions such as the vertical direction during the annealing process.

[0071] The conditions of the annealing process are appropriately set according to the thickness and reduction ratio of the metal plate 64. For example, the annealing process is performed within a range of 500°C or higher and 600°C or lower for 30 seconds or more and 90 seconds or less. The above seconds represent the time required for the metal plate 64 to pass through a space adjusted to a predetermined temperature in the annealing device 67. The temperature of the annealing process may be set so that softening of the metal plate 64 does not occur.

[0072] The lower limit of the temperature of the annealing process may be lower than the above-mentioned 500°C. For example, the temperature of the annealing process may be 400°C or higher, or may be 450°C or higher. Also, the upper limit of the temperature of the annealing process may be higher than the above-mentioned 600°C. For example, the temperature of the annealing process may be 700°C or lower, or may be 650°C or lower. Further, the temperature range of the annealing process may be determined by any combination of any one of the above-mentioned plurality of candidate values for the upper limit and any one of the above-mentioned plurality of candidate values for the lower limit. For example, the temperature of the annealing process may be 400°C or higher and 700°C or lower, or may be 450°C or higher and 650°C or lower. Also, the temperature range of the annealing process may be determined by any combination of any two of the above-mentioned plurality of candidate values for the upper limit. For example, the temperature of the annealing process may be 650°C or higher and 700°C or lower. Also, the temperature range of the annealing process may be determined by any combination of any two of the above-mentioned plurality of candidate values for the lower limit. For example, the temperature of the annealing process may be 400°C or higher and 450°C or lower.

[0073] The time of the annealing process may be 40 seconds or more, and may also be 50 seconds or more. Also, the lower limit of the time of the annealing process may be shorter than the above-mentioned 30 seconds. For example, the time of the annealing process may be 10 seconds or more, and may also be 20 seconds or more. Also, the time of the annealing process may be 80 seconds or less, may also be 70 seconds or less, and may also be 60 seconds or less. Also, the upper limit of the time of the annealing process may be longer than the above-mentioned 90 seconds. For example, the time of the annealing process may be 100 seconds or less. Also, the range of the time of the annealing process may be determined by any combination of any one of the above-mentioned plurality of candidate values for the upper limit and any one of the above-mentioned plurality of candidate values for the lower limit. For example, the time of the annealing process may be 10 seconds or more and 100 seconds or less, may also be 20 seconds or more and 90 seconds or less, may also be 30 seconds or more and 80 seconds or less, may also be 40 seconds or more and 70 seconds or less, and may also be 50 seconds or more and 60 seconds or less. Also, the range of the time of the annealing process may be determined by any combination of any two of the above-mentioned plurality of candidate values for the upper limit. For example, the time of the annealing process may be 90 seconds or more and 100 seconds or less. Also, the range of the time of the annealing process may be determined by any combination of any two of the above-mentioned plurality of candidate values for the lower limit. For example, the time of the annealing process may be 10 seconds or more and 20 seconds or less.

[0074] Preferably, the annealing process described above is carried out in a non-reducing atmosphere or an inert gas atmosphere. Here, the non-reducing atmosphere means an atmosphere that does not contain a reducing gas such as hydrogen. "Not containing a reducing gas" means that the concentration of a reducing gas such as hydrogen is 10% or less. In the annealing process, the concentration of the reducing gas may be 8% or less, 6% or less, 4% or less, 2% or less, or 1% or less. Also, the inert gas atmosphere means an atmosphere in which the concentration of an inert gas such as argon gas, helium gas, or nitrogen gas is 90% or more. In the annealing process, the concentration of the inert gas may be 92% or more, 94% or more, 96% or more, 98% or more, or 99% or more. By carrying out the annealing process in a non-reducing atmosphere or an inert gas atmosphere, it is possible to suppress the formation of nickel compounds such as nickel hydroxide on the surface layer of the metal plate 64. The annealing apparatus 67 may have a mechanism for monitoring the concentration of the inert gas and a mechanism for adjusting the concentration of the inert gas.

[0075] Before the annealing process, a cleaning process for cleaning the metal plate 64 may be carried out. Thereby, it is possible to suppress the adhesion of foreign substances to the surface of the metal plate 64 during the annealing process. As the cleaning liquid for cleaning, for example, a hydrocarbon-based liquid can be used.

[0076] Also, in FIG. 12, an example in which the annealing process is carried out while pulling the metal plate 64 in the longitudinal direction is shown, but it is not limited to this, and the annealing process may be carried out with the metal plate 64 wound around the core 61. That is, batch annealing may be carried out. When the annealing process is carried out with the metal plate 64 wound around the core 61, the metal plate 64 may develop a warp habit according to the winding diameter of the winding body 62. Therefore, depending on the winding diameter of the winding body 62 and the material constituting the base material 60, it is advantageous to carry out the annealing process while pulling the metal plate 64 in the longitudinal direction.

[0077] Thereafter, a slitting process may be performed to cut off both ends in the width direction of the metal plate 64 obtained by the rolling process 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 at both ends of the metal plate 64 due to rolling. By performing such a slitting process, it is possible to prevent a phenomenon in which the metal plate 64 breaks, so-called plate breakage, from occurring starting from the cracks.

[0078] The width of the portion cut off in the slitting process may be adjusted so that the shape of the metal plate 64 after the slitting process is symmetric in the width direction. Also, the slitting process may be performed before the above-described annealing process.

[0079] Note that a long metal plate 64 with a predetermined thickness may be manufactured by repeating at least two of the above-described rolling process, annealing process, and slitting process a plurality of times.

[0080] Also, an appearance inspection process for inspecting the appearance of the metal plate 64 may be performed after the rolling process or after the annealing process. The appearance inspection process may include a process of inspecting the appearance of the metal plate 64 using an automatic inspection machine. Also, the appearance inspection process may include a process of visually inspecting the appearance of the metal plate 64.

[0081] Also, a shape inspection process for inspecting the shape of the metal plate 64 may be performed after the rolling process or after the annealing process. For example, using a three-dimensional measuring instrument, 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.

[0082] Incidentally, as a result of intensive research by the inventors of the present invention, it has been found that there are many depressions on the surface of the rolled metal plate 64. FIG. 13 is a diagram showing a state in which a plurality of depressions 64c exist, for example, on the first surface 64a of the surface of the metal plate 64 obtained by rolling. The depressions 64c are, for example, oil pits 64e and rolling streaks 64f. The oil pit 64e is a recess formed on the surface of the metal plate 64 due to the oil existing between the base material 60 and the rolling rolls 66a and 66b. In the present embodiment, the depression 64c means a recess having a depth of 0.2 μm or more among the recesses such as the oil pit 64e existing on the surface of the metal plate 64. The density of the depressions 64c existing on the surface of the metal plate 64 is, for example, 3 pieces / mm 2 or more and 500 pieces / mm 2 or less. The numerical value of 0.2 μm is a preferable value of the correction distance dC described later. Further, the dimension of the depression 64c in the plane direction of the metal plate 64 is, for example, 1 μm or more and 60 μm or less.

[0083] As a technique for inspecting the undulations such as the depressions 64c on the surface of the metal plate 64, a technique of calculating the arithmetic mean roughness Ra and the maximum height Ry of the surface is known. In both the arithmetic mean roughness Ra and the maximum height Ry, the position of the surface of the metal plate 64 in the thickness direction is measured at a plurality of points on a predetermined straight line such as the straight line R1 and the straight line R2 shown in FIG. 13. On the other hand, as shown in FIG. 13, the density of the depressions 64c may vary depending on the location. As a result, as shown in FIG. 13, the density of the depressions 64c located on the straight line R2 can be significantly lower than the density of the depressions 64c located on the straight line R1. Thus, in techniques such as the arithmetic mean roughness Ra and the maximum height Ry, the variation in the inspection results can be relatively large.

[0084] Further, in techniques such as the arithmetic mean roughness Ra and the maximum height Ry, it is considered that sufficient information regarding the shape and volume of the depression 64c cannot be obtained. Such problems of the arithmetic mean roughness Ra and the maximum height Ry will be described with reference to FIG. 14. FIG. 14 is a diagram showing an example of a cross section of the metal plate 64.

[0085] FIG. 14 shows three types of depressions. The depression 64c_1 located on the left side and the depression 64c_2 located in the center have the same opening diameter A. The wall surface of the depression 64c_1 has a shape that protrudes toward the metal plate. On the other hand, the wall surface of the depression 64c_2 has a shape that protrudes outward, contrary to the depression 64c_1. The two depressions 64c_3 located on the right side have an opening diameter of A / 2. That is, the sum of the opening diameters of the two depressions 64c_3 is the same as the opening diameter of the depression 64c_1 and the opening diameter of the depression 64c_2. The depths of the three types of depressions 64c_1, 64c_2, and 64c_3 are all B. When measuring the surface roughness caused by the three types of depressions 64c_1, 64c_2, and 64c_3 with a measuring instrument, the arithmetic mean roughness Ra is expressed by the following formula. Ra = ∫A×B / 2dx Therefore, the influence of the three types of depressions 64c_1, 64c_2, and 64c_3 on the measured value of the arithmetic mean roughness Ra is the same. On the other hand, as shown in FIGS. 15 to 17, the dimensions of the through holes 25, the first recesses 30, the second recesses 35, the top portions 43, the rib portions, etc. formed by etching the metal plate 64 are affected not only by the depth of the depression 64c but also by the volume of the depression 64c. As will be described later, in this embodiment, the surface roughness is evaluated based on the volume of the depression. In this case, the degrees of influence of the three types of depressions 64c_1, 64c_2, and 64c_3 on the depression correction volume density described later are different. Specifically, the degree of influence of the depression 64c_1 on the depression correction volume density is the largest. Also, the degree of influence of one depression 64c_2 on the depression correction volume density is smaller than the degree of influence of the two depressions 64c_3 on the depression correction volume density.

[0086] FIG. 15 is a cross-sectional view showing a process of etching the metal plate 64 shown in FIG. 14 from the first surface 64a side using the first resist pattern 65a as a mask to form the first recess 30. The volume of the left depression 64c_1 is larger than the volume of the right depression 64c_2. For this reason, at the location where the left depression 64c_1 exists, etching proceeds in the thickness direction and the plane direction of the metal plate 64 earlier than at the location where the right depression 64c_2 exists. For this reason, the dimensions of the first recess 30_1 formed at the location where the left depression 64c_1 exists are larger than the dimensions of the first recess 30_2 formed at the location where the right depression 64c_2 exists.

[0087] FIG. 16 is a cross-sectional view showing a process of etching the metal plate 64 shown in FIG. 15 from the second surface 64b side using the second resist pattern 65b as a mask to form the second recess 35 communicating with the first recesses 30_1 and 30_2 on the second surface 64b side of the metal plate 64. Since the dimensions of the left first recess 30_1 are larger than the dimensions of the right first recess 30_2, the dimensions of the contour of the connection portion 41 where the left first recess 30_1 and the second recess 35 are connected are also larger than the dimensions of the contour of the connection portion 41 where the right first recess 30_2 and the second recess 35 are connected.

[0088] FIG. 17 is a diagram for explaining a state in which the accuracy of the opening dimension of the through hole 25 on the first surface 20a side decreases due to the depression 64c of the metal plate 64. In a portion where there is a depression 64c with a large volume, at the start of the etching process, the etching solution can penetrate into the depression 64c. For this reason, in a portion where there is a depression 64c with a large volume, etching can proceed in the thickness direction and the surface direction of the metal plate 64 earlier than in other portions. Therefore, for example, when a depression 64c with a large volume exists near the end of the opening of the first resist pattern 65a or near the end of the opening of the second resist pattern 65b in the metal plate 64, in the portion where the depression 64c exists, the dimension of the through hole 25 in the surface direction of the metal plate 64 can become larger. As a result, as indicated by reference numeral 30_1 in FIG. 17, in a place where there is a depression 64c with a large volume, variations in the dimension r3 of the first recess 30 constituting the through hole 25 on the first surface 20a can occur. Further, variations in the dimension r2 of the through portion 42 formed by the connection portion 41 connecting the first recess 30 and the second recess 35 can also occur. As a result, it is considered that the dimensional accuracy and the positional accuracy of the vapor deposition material attached to the organic EL substrate 92 will decrease. Such variations in the opening dimension can also occur in the second recess 35 on the second surface 20b side.

[0089] As described above, whether or not the through hole 25 can be precisely formed in the metal plate 64 depends not only on the depth of the depression 64c formed on the surface of the metal plate 64 but also greatly on the volume of the depression 64c. On the other hand, a technique based on the conventional arithmetic mean roughness Ra or the like cannot appropriately obtain information regarding the volume of the depression 64c. For this reason, when inspecting the metal plate 64 using the arithmetic mean roughness Ra, in order to prevent a metal plate 64 inappropriate for manufacturing the vapor deposition mask 20 from passing the inspection, it is necessary to make the pass / fail judgment threshold stricter than necessary. As a result, it is considered that the yield of the metal plate 64 will decrease.

[0090] To solve such problems, in this embodiment, it is proposed to perform the inspection of the metal plate 64 in consideration of the volume of the recess 64c. Thereby, the degree of reduction in the dimensional accuracy of the through hole 25 of the vapor deposition mask 20 caused by the recess 64c can be predicted more accurately. For this reason, the inspection of the metal plate 64 can be performed without making the pass / fail determination threshold stricter than necessary, and the yield of the metal plate 64 can be increased. Hereinafter, an example of the inspection process considering the volume of the recess 64c will be described with reference to FIGS. 18 and 19.

[0091] FIG. 18 is a plan view showing a partially enlarged view of the first surface 64a of the metal plate 64. A plurality of recesses 64c are formed in the first surface 64a. In FIG. 19, the symbol D1 represents the conveyance direction of the metal plate 64 during the rolling process (hereinafter, also referred to as the first direction). The symbol D2 represents a direction orthogonal to the first direction D1 (hereinafter, also referred to as the second direction).

[0092] In the inspection process, the quality of the metal plate 64 is determined based on the volumes of the plurality of recesses 64c located in the inspection region 711 of the first surface 64a shown in FIG. 18. The area U1 of the inspection region 711 is, for example, 0.1 mm 2 or more and 1.5 mm 2 or less. By setting the area U1 of the inspection region 711 to 0.1 mm 2 or more, it is possible to suppress variations in the inspection results based on the position of the inspection region 711. Also, by setting the area U1 of the inspection region 711 to 1.5 mm 2 or less, it is possible to suppress an excessive increase in the time required for the inspection.

[0093] The inspection process includes a calculation process S1 and a determination process S2. In the calculation process S1, a recess correction volume density is calculated. The recess correction volume density is an index having a high correlation with the dimensional accuracy of the components of the vapor deposition mask 20, as supported in the examples described later. In the determination process, when the recess correction volume density is equal to or less than a predetermined threshold value, the metal plate 64 is determined to be good.

[0094] First, the calculation step S1 will be described. The calculation step S1 includes a measurement step S11 and a processing step S12. In the measurement step S11, first, as shown in FIG. 18, imaging is performed in each of a plurality of unit regions 712, and the depth of the depression 64c is measured from the obtained image. The unit region 712 is, for example, a rectangular region having a side of length W1 and a side of length W2 as shown in FIG. 18. The unit region 712 corresponds to the range of an image that can be acquired in one imaging. In the example shown in FIG. 18, the side of length W1 is parallel to the first direction D1, and the side of length W2 is parallel to the second direction D2. For example, W1 is 270 μm and W2 is 202 μm. Note that the side of length W1 being parallel to the first direction D1 means that the angle formed by the side of length W1 and the first direction D1 is within the range of -10° to +10°. Similarly, the side of length W2 being parallel to the second direction D2 means that the angle formed by the side of length W2 and the second direction D2 is within the range of -10° to +10°.

[0095] As shown in FIG. 18, the plurality of imaging operations are performed such that two adjacent unit regions 712 in the first direction D1 partially overlap, and two adjacent unit regions 712 in the second direction D2 also partially overlap. By connecting the plurality of obtained images using image connection software or the like, an image of a region wider than one unit region 712 can be obtained. Then, from the image obtained by the connection, for example, the region indicated by reference numeral 711 in FIG. 18 is extracted as an inspection region. For example, the inspection region 711 is defined so as to surround one unit region 712 located at the center among the nine unit regions 712 shown in FIG. 18 and partially include each of the eight unit regions 712 located around it. The length of the inspection region 711 in the first direction D1 is, for example, 700 μm, and the length of the inspection region 711 in the second direction D2 is, for example, 500 μm.

[0096] In FIG. 18, reference numeral 713 indicates a pixel corresponding to the resolution of the inspection device. One pixel 713 corresponds to, for example, one spot of the laser that the inspection device irradiates on the metal plate 64. The length W3 and the length W4 of the pixel 713 in the first direction D1 and the second direction D2 are preferably 0.1 μm or more and 0.4 μm or less. Also, the area U2 of the pixel 713 is preferably 0.01 μm 2 or more and 0.2 μm 2 or less. When the area of the unit region 712 is 270 μm × 202 μm and the resolution of the unit region 712 in the first direction D1 and the second direction D2 is 1024 × 768, the length W3 and the length W4 of the pixel 713 in the first direction D1 and the second direction D2 are both 0.263 μm. Also, the area U2 of the pixel 713 is 0.069 μm 2 in this case.

[0097] FIG. 19 is a cross-sectional view showing a case where the metal plate 64 in which the depression 64c is formed is cut parallel to the first direction D1. In FIG. 19, reference numeral d(k) represents the distance from the first surface 64a to the bottom surface of the depression 64c in the pixel 713 located at the coordinate x(k) in the first direction D1. k is an integer, and the range that k can take is determined by the resolution of the image.

[0098] In addition, on the first surface 64a of the metal plate 64, in addition to the distinct depression 64c as shown in FIG. 19, there may be fine irregularities and undulations. For this reason, when measuring the depth of the depression 64c with reference to the first surface 64a, variations may occur in the measurement result of the depth of the depression 64c due to the state of the first surface 64a around the depression 64c. Considering such problems, in the measurement step S11 and the processing step S12, the position of a reference plane RP, which is a virtual plane, may be adopted as the position of the first surface 64a in the thickness direction of the metal plate 64. Hereinafter, the reference plane RP will be described.

[0099] The reference plane RP of the first surface 64a is, for example, a plane estimated by the least squares method. Specifically, first, the position of the inspection region 711 in the thickness direction of the surface of the first surface 64a of the metal plate 64 is measured using a laser microscope described later. Subsequently, a predetermined plane is temporarily set as the reference plane RP, and the square of the distance from the position of the surface of the first surface 64a to the reference plane RP is calculated for each pixel 713. In this case, a plane with the minimum sum of the squares of the distances can be adopted as the reference plane RP.

[0100] In the measurement step S11, as shown in FIG. 19, the depth d(k) of the depression 64c is measured at each pixel 713 of the inspection region 711. The measured value of the depth is the value of the distance from the measured value of the position in the thickness direction of the surface of the first surface 64a of the metal plate 64 to the reference plane RP estimated by the least squares method.

[0101] As the inspection device used in the measurement step S11, for example, a laser microscope can be used. In the measurement using a laser microscope, first, the inspection region 711 of the first surface 64a of the metal plate 64 is irradiated with laser light. Subsequently, the laser light reflected by the inspection region 711 is photographed as a two-dimensional reflected image of the inspection region 711 using an image sensor such as a CCD or a CMOS. Also, based on the principle of a confocal microscope, the two-dimensional reflected image is analyzed to measure the position of each pixel 713 of the inspection region 711 in the thickness direction of the surface of the first surface 64a of the metal plate 64. As the laser microscope, for example, the laser microscope VK-X200 series manufactured by Keyence Corporation can be used.

[0102] In the processing step S12, information regarding the volume of the depression 64c within the inspection region 711 is calculated based on the depth of the depression 64c measured at each pixel 713 within the inspection region 711.

[0103] In the present embodiment, first, as shown in FIG. 19, a correction plane CP located on the second surface 64b side by a predetermined correction distance dC from a reference plane RP in the thickness direction of the metal plate 64 is set. Subsequently, the sum of the volumes of the portions of the depressions 64c located in the inspection region 711 and on the second surface 64b side of the correction distance dC in the thickness direction of the metal plate 64 is calculated. For example, for the portions of the depressions 64c located in the inspection region 711 and having a depth greater than the correction distance dC, a value d(k) - dC obtained by subtracting the correction distance dC from the depth d(k) is calculated. Subsequently, the value d(k) - dC is multiplied by the area U2 of the pixel 713. Thereby, in each pixel 713, the volume V(k) of the portion of the depression 64c located on the second surface 64b side of the correction plane CP (={(d(k) - dC)×U2}) is calculated. Subsequently, each volume V(k) is integrated over the entire inspection region 711. Thereby, the sum of the volumes of the portions of the depressions 64c located in the inspection region 711 and on the second surface 64b side of the correction plane CP (hereinafter also referred to as the depression correction volume) V1 can be calculated.

[0104] Subsequently, the depression correction volume V1 is divided by the area U1 of the inspection region 711. Thereby, the depression correction volume per unit area (hereinafter also referred to as the depression correction volume density) V2 can be calculated.

[0105] The above-described correction distance dC is preferably 0.1 μm or more and 0.5 μm or less, and is, for example, 0.2 μm. By appropriately setting the correction distance dC and calculating the depression correction volume density V2, as supported by the examples described later, the correlation between the depression correction volume density V2 and the dimensional accuracy of the components of the vapor deposition mask 20 can be enhanced. In the following description, the depression correction volume V1 and the depression correction volume density V2 obtained when the correction distance dC is set to z μm may be denoted as the depression correction volume V1(z μm) and the depression correction volume density V2(z μm), respectively. For example, when the correction distance dC is 0.2 μm, the notations of the depression correction volume V1(0.2 μm) and the depression correction volume density V2(0.2 μm) may be adopted.

[0106] Subsequently, a determination step S2 is performed to determine that the metal plate 64 is good when the depression correction volume density V2 is equal to or less than a predetermined threshold value TH1. As a result, it is possible to select a metal plate 64 that can accurately form components of the vapor deposition mask 20 such as the through holes 25.

[0107] The threshold value TH1 is appropriately determined based on the dimensional accuracy required for the components of the vapor deposition mask 20, the setting of the correction distance dC, and the like. For example, when the error in the opening dimension of the through hole 25 of the vapor deposition mask 20 such as r3 of the first recess 30 and r2 of the dimension of the through portion 42 described above is required to be ±1.0 μm or less, and the correction distance dC is 0.2 μm, the threshold value TH1 can be set to 15000 μm 3 / mm 2 It can be determined to. The threshold value TH1 may be 12000 μm 3 / mm 2 It may be, 10000 μm 3 / mm 2 It may be, 9000 μm 3 / mm 2 It may be, 6000 μm 3 / mm 2 It may be, 5000 μm 3 / mm 2 It may be, 3000 μm 3 / mm 2 It may be, 1000 μm 3 / mm 2 It may be.

[0108] In the determination step S2, the metal plate 64 may be determined to be good when the depression correction volume density V2 is equal to or greater than the threshold value TH2 and equal to or less than the threshold value TH1. That is, in the determination step S2, in addition to the threshold value TH1 that defines the upper limit of the depression correction volume density V2, a threshold value TH2 that defines the lower limit of the depression correction volume density V2 may be used. Since the metal plate 64 has a depression correction volume density V2 equal to or greater than the threshold value TH2, the adhesion of the resist film to the surface of the metal plate 64 can be enhanced. The upper threshold value TH1 may be referred to as a first threshold value, and the lower threshold value TH2 may be referred to as a second threshold value. The threshold value TH2 may be 10 μm 3 / mm 2 It may be, 100 μm3 / mm 2 may be, 500 μm 3 / mm 2 may be, 1000 μm 3 / mm 2 may be, 3000 μm 3 / mm 2 may be, 4000 μm 3 / mm 2 may be, 5000 μm 3 / mm 2 may be acceptable.

[0109] The range of the depression correction volume density V2 of the metal plate 64 determined to be good in the determination step S2 may be determined by any combination of any one of the plurality of upper threshold candidates TH1 and any one of the plurality of lower threshold candidates TH2 described above. For example, the depression correction volume density V2 of the metal plate 64 determined to be good, that is, the selected metal plate 64, may be 10 μm 3 / mm 2 or more and 15000 μm 3 / mm 2 or less, may be 100 μm 3 / mm 2 or more and 12000 μm 3 / mm 2 or less, may be 500 μm 3 / mm 2 or more and 10000 μm 3 / mm 2 or less, may be 1000 μm 3 / mm 2 or more and 9000 μm 3 / mm 2 or less, may be 3000 μm 3 / mm 2 or more and 6000 μm 3 / mm 2 or less, may be 4000 μm 3 / mm 2 or more and 6000 μm 3 / mm 2The following may also be applicable. Also, the range of the depression correction volume density V2 of the selected metal plate 64 may be determined by any combination of two of the above-mentioned candidates for the upper limit threshold value TH1. For example, the depression correction volume density V2 of the selected metal plate 64 is 12000 μm 3 / mm 2 or more and 15000 μm 3 / mm 2 or less. Also, the range of the depression correction volume density V2 of the selected metal plate 64 may be determined by any combination of two of the above-mentioned candidates for the lower limit threshold value TH2. For example, the depression correction volume density V2 of the selected metal plate 64 is 10 μm 3 / mm 2 or more and 100 μm 3 / mm 2 or less.

[0110] FIG. 39 is a diagram showing an example of the distribution of the depression correction volume density V2 of a plurality of metal plates 64 selected based on the determination condition for determining a metal plate with a depression correction volume density V2 equal to or less than the threshold value TH1 as a non-defective product. In FIG. 39, the horizontal axis represents the value of the depression correction volume density V2 calculated for each metal plate 64. The vertical axis represents the number of metal plates 64 having the depression correction volume density V2 in the range shown on the horizontal axis. For example, among the plurality of selected metal plates 64, the number of metal plates 64 having a depression correction volume density V2 of 6000 μm 3 / mm 2 or more and 9000 μm 3 / mm 2 or less is 17.

[0111] In the example of FIG. 39, the threshold value TH1 is 15000 μm 3 / mm 2 . In this case, most of the metal plates 64 determined as non-defective products, for example, 95% or more, have a depression correction volume density V2 of 15000 μm 3 / mm 2 or less. As shown in FIG. 39, due to measurement errors or the like, some of the selected metal plates 64 have a value of 15000 μm 3 / mm 2There may also be a case where the depression correction volume density V2 exceeds it.

[0112] FIG. 40 is a diagram showing an example of the distribution of the depression correction volume density V2 of a plurality of metal plates 64 selected based on the determination condition for determining a metal plate having a depression correction volume density V2 equal to or greater than the threshold value TH2 and equal to or less than the threshold value TH1 as a good product. The meanings of the horizontal axis and the vertical axis shown in FIG. 40 are the same as those in the case of FIG. 39. In the example of FIG. 40, the threshold value TH2 is 3000 μm 3 / mm 2 and the threshold value TH1 is 15000 μm 3 / mm 2 . Thus, in the example of FIG. 40, the range of the metal plates 64 selected as good products is narrower than that in the example of FIG. 39. In this case, when the selection shown in FIG. 40 is performed, the selection shown in FIG. 39 is also performed.

[0113] In the above description, an example in which the inspection process for inspecting the metal plate 64 based on the depression correction volume density V2 is used for determining the quality of the metal plate 64, that is, for performing the selection of the metal plate 64, is shown. That is, an example in which the inspection process functions as a selection process for selecting the metal plate 64 in the manufacturing method of the metal plate 64 is shown. However, the inspection process may be used for purposes other than the selection of the metal plate 64 in the manufacturing method of the metal plate 64.

[0114] Note that the selection conditions in the selection process are arbitrary. For example, the selection process may select the metal plate 64 having a depression correction volume density V2 belonging to a range determined by any combination of any one of the plurality of upper threshold value candidates TH1 described above and any one of the plurality of lower threshold value candidates TH2 described above. Further, the selection process may select the metal plate 64 having a depression correction volume density V2 belonging to a range determined by any combination of any two of the plurality of upper threshold value candidates TH1 described above. Further, the selection process may select the metal plate 64 having a depression correction volume density V2 belonging to a range determined by any combination of any two of the plurality of lower threshold value candidates TH2 described above.

[0115] An example of using the inspection process for purposes other than sorting the metal plate 64 in the manufacturing method of the metal plate 64 will be described. For example, the inspection process may be used to optimize the conditions for manufacturing the metal plate 64, such as the rolling ratio and the amount of oil used. Specifically, the metal plate 64 is manufactured with various rolling ratios and amounts of oil used, the depression correction volume density V2 of each obtained metal plate 64 is calculated, and appropriate manufacturing conditions that can lower the depression correction volume density V2 are set. For this operation, the inspection process may be used. In this case, in the manufacturing process of the metal plate 64, it is not necessary to perform sorting based on the inspection process for all the metal plates 64. For example, the inspection process may be performed only on some of the metal plates 64. Or, after the manufacturing conditions are once set, the inspection process may not be performed at all.

[0116] FIG. 41 is a diagram showing an example of the distribution of the depression correction volume density V2 of a plurality of metal plates 64 manufactured based on the manufacturing conditions found using the determination condition for determining a metal plate having a depression correction volume density V2 of a threshold value TH1 or less as a non-defective product. The meanings of the horizontal axis and the vertical axis shown in FIG. 41 are the same as those in the case of FIG. 39. In the example of FIG. 41, the threshold value TH1 is 15000 μm 3 / mm 2 In the example of FIG. 41, even when the sorting process is not performed, the plurality of manufactured metal plates 64 have a depression correction volume density V2 of 15000 μm 3 / mm 2 or less.

[0117] According to the manufacturing method of the metal plate according to the present embodiment, a metal plate 64 having a depression correction volume density V2 that satisfies the above-described determination condition can be obtained. For example, a metal plate 64 having a depression correction volume density V2 of 15000 μm 3 / mm 2 or less can be obtained. Thereby, it is possible to suppress a decrease in the dimensional accuracy of the through hole 25 of the vapor deposition mask 20 due to the depression 64c. As a result, the dimensional accuracy and the positional accuracy of the vapor deposition material attached to the organic EL substrate 92 through the through hole 25 can be improved.

[0118] Next, a method for manufacturing the vapor deposition mask 20 using the metal plate 64 that has passed the above-described inspection process will be described mainly with reference to FIGS. 20 to 28. FIG. 20 is a diagram showing a manufacturing apparatus 70 for manufacturing the vapor deposition mask 20 using the metal plate 64. First, a wound body 62 in which the metal plate 64 is wound around the core 61 is prepared. Then, by rotating the core 61 and unwinding the wound body 62, a metal plate 64 extending in a strip shape is supplied as shown in FIG. 20.

[0119] The supplied metal plate 64 is sequentially conveyed by the conveying roller 75 to the processing device 72 and the separating device 73. The processing device 72 performs a processing step of processing the metal plate 64 that has passed the inspection process to form through holes 25 in the metal plate 64. In the present embodiment, a large number of through holes 25 corresponding to a plurality of vapor deposition masks 20 are formed in the metal plate 64. In other words, a plurality of vapor deposition masks 20 are assigned to the metal plate 64. The separating device 73 performs a separating step of separating a portion of the metal plate 64 in which a plurality of through holes 25 corresponding to one vapor deposition mask 20 are formed from the metal plate 64. In this way, a sheet-like vapor deposition mask 20 can be obtained.

[0120] With reference to FIGS. 20 to 28, the processing step will be described. The processing step includes a step of performing etching using photolithography technology on the long metal plate 64 to form a first recess 30 from the side of the first surface 64a of the metal plate 64, and a step of performing etching using photolithography technology on the metal plate 64 to form a second recess 35 from the side of the second surface 64b of the metal plate 64. Then, the through hole 25 is formed in the metal plate 64 by the first recess 30 and the second recess 35 formed in the metal plate 64 communicating with each other. In the example described below, the step of forming the first recess 30 is performed before the step of forming the second recess 35, and a step of sealing the formed first recess 30 is performed between the step of forming the first recess 30 and the step of forming the second recess 35. Hereinafter, the details of each step will be described.

[0121] First, as shown in FIG. 21, resist films 65c and 65d 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 solution containing a photosensitive resist material such as casein is applied onto the first surface 64a and the second surface 64b of the metal plate 64, and then the coating solution is dried to form the resist films 65c and 65d. Alternatively, the resist films 65c and 65d may be formed by attaching dry films onto the first surface 64a and the second surface 64b of the metal plate 64. The dry film contains, for example, an acrylic-based photocurable resin.

[0122] Next, exposure masks 68a and 68b that prevent light from passing through the regions of the resist films 65c and 65d to be removed are prepared, and the exposure masks 68a and 68b are respectively placed on the resist films 65c and 65d as shown in FIG. 22. At this time, an alignment process for adjusting the relative positional relationship between the exposure mask 68a on the first surface 64a side and the exposure mask 68b on the second surface 64b side may be performed. As the exposure masks 68a and 68b, for example, glass dry plates that prevent light from passing through the regions of the resist films 65c and 65d to be removed are used. Then, the exposure masks 68a and 68b are sufficiently adhered to the resist films 65c and 65d by vacuum adhesion. Note that a positive photosensitive resist material may be used as the photosensitive resist material. In this case, as the exposure mask, an exposure mask that allows light to pass through the regions of the resist film to be removed is used.

[0123] Thereafter, the resist films 65c and 65d are exposed through the exposure masks 68a and 68b (exposure step). Further, the resist films 65c and 65d are developed to form images on the exposed resist films 65c and 65d (development step). As described above, as shown in FIG. 23, the first resist pattern 65a can be formed on the first surface 64a of the metal plate 64, and the second resist pattern 65b can be formed on the second surface 64b of the metal plate 64. The development step may include a resist heat treatment step for increasing the hardness of the resist films 65c and 65d or for more firmly adhering the resist films 65c and 65d to the metal plate 64. The resist heat treatment step can be carried out, for example, at a temperature of room temperature or higher and 400°C or lower.

[0124] Next, as shown in FIG. 24, a first surface etching step is performed in which a region of the first surface 64a of the metal plate 64 that is not covered by the first resist pattern 65a is etched using a first etching solution. For example, the first etching solution is sprayed from a nozzle disposed on the side facing the first surface 64a of the conveyed metal plate 64 through the first resist pattern 65a toward the first surface 64a of the metal plate 64. As a result, as shown in FIG. 24, corrosion by the first etching solution progresses in the region of the metal plate 64 that is not covered by the first resist pattern 65a. Thereby, a large number of first recesses 30 are formed in the first surface 64a of the metal plate 64. As the first etching solution, for example, one containing ferric chloride solution and hydrochloric acid is used.

[0125] Thereafter, as shown in FIG. 25, the first recesses 30 are covered with a resin 69 having resistance to the second etching solution used in the subsequent second surface etching step. That is, the first recesses 30 are sealed with the resin 69 having resistance to the second etching solution. In the example shown in FIG. 25, the film of the resin 69 is formed so as to cover not only the formed first recesses 30 but also the first surface 64a (first resist pattern 65a).

[0126] Next, as shown in FIG. 26, an area of the second surface 64b of the metal plate 64 that is not covered by the second resist pattern 65b is etched to perform a second surface etching process for forming a second recess 35 in the second surface 64b. The second surface etching process is carried out until the first recess 30 and the second recess 35 communicate with each other, thereby forming a through hole 25. As the second etching solution, similar to the above-described first etching solution, for example, a solution containing ferric chloride solution and hydrochloric acid is used.

[0127] Note that the erosion by the second etching solution progresses in the portion of the metal plate 64 that is in contact with the second etching solution. Therefore, the erosion does not only progress in the normal direction N (thickness direction) of the metal plate 64, but also progresses in the direction along the plate surface of the metal plate 64. Here, preferably, the second surface etching process ends before the two second recesses 35 formed at positions facing two adjacent holes 67b of the second resist pattern 65b merge on the back side of the bridge portion 67a located between the two holes 67b. Thereby, as shown in FIG. 27, the above-described top portion 43 can be left on the second surface 64b of the metal plate 64.

[0128] Thereafter, as shown in FIG. 28, the resin 69 is removed from the metal plate 64. The resin 69 can be removed, for example, by using an alkaline stripping solution. When an alkaline stripping solution is used, as shown in FIG. 28, the resist patterns 65a and 65b are also removed simultaneously with the resin 69. Note that after removing the resin 69, the resist patterns 65a and 65b may be removed separately from the resin 69 by using a stripping solution different from the stripping solution for stripping the resin 69.

[0129] Thereafter, the vapor deposition mask 20 can be obtained by separating a portion of the metal plate 64 in which a plurality of through holes 25 corresponding to one vapor deposition mask 20 are formed from the metal plate 64.

[0130] Next, a method for manufacturing the vapor deposition mask apparatus 10 by combining the vapor deposition mask 20 and the frame 15 will be described. First, the frame 15 is prepared. Subsequently, the second surface 20b of the vapor deposition mask 20 is fixed to the frame 15 by welding or the like. For example, first, with the frame 15 and the vapor deposition mask 20 overlapped, the vapor deposition mask 20 is photographed from the first surface 20a side using a camera or the like. At this time, tension may be applied to the vapor deposition mask 20. Subsequently, based on the image obtained by the photographing, the position of the vapor deposition mask 20 with respect to the frame 15 is detected. For example, the position of the contour of the vapor deposition mask 20 in the longitudinal direction D1 is detected. Subsequently, the position of the vapor deposition mask 20 is adjusted so that the position of the vapor deposition mask 20 with respect to the frame 15 becomes a predetermined position.

[0131] Next, a vapor deposition method for vapor-depositing the vapor deposition material 98 onto a substrate such as the organic EL substrate 92 using the vapor deposition mask 20 will be described. First, the vapor deposition mask apparatus 10 is arranged so that the vapor deposition mask 20 faces the organic EL substrate 92. Also, the vapor deposition mask 20 is brought into close contact with the organic EL substrate 92 using the magnet 93. In this state, by evaporating the vapor deposition material 98 and causing it to fly onto the organic EL substrate 92 through the vapor deposition mask 20, the vapor deposition material 98 can be attached to the organic EL substrate 92 in a pattern corresponding to the through holes 25 of the vapor deposition mask 20.

[0132] In the method for manufacturing the vapor deposition mask 20 according to the present embodiment, the vapor deposition mask 20 is manufactured using the metal plate 64 that has passed the inspection process carried out based on the total volume of the depressions 64c formed on the surface of the metal plate 64. Therefore, it is possible to suppress a decrease in the dimensional accuracy of the through holes 25 of the vapor deposition mask 20 due to the depressions 64c. As a result, the dimensional accuracy and the position accuracy of the vapor deposition material attached to the organic EL substrate 92 through the through holes 25 can be improved.

[0133] It should be noted that various modifications can be made to the above-described embodiments. Hereinafter, modification examples will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, for parts that can be configured in the same manner as those in the above-described embodiments, the same reference numerals as those used for the corresponding parts in the above-described embodiments will be used, and duplicate descriptions will be omitted. Further, when it is clear that the operational effects obtained in the above-described embodiments can also be obtained in the modification examples, the description thereof may be omitted.

[0134] In the above-described embodiment, in the inspection process, an example was shown in which the first surface 64a of the metal plate 64 where the first recess 30 is formed is the inspection target. However, the present invention is not limited to this, and in the inspection process, the second surface 64b of the metal plate 64 where the second recess 35 is formed may be the inspection target. Further, both the first surface 64a and the second surface 64b of the metal plate 64 may be the inspection targets.

[0135] In the above-described embodiment, an example was shown in which the inspection process of the metal plate 64 is carried out by equipment different from the equipment for implementing the manufacturing method of the vapor deposition mask 20 such as the above-described processing process and separation process. In other words, an example was shown in which the inspection process of the metal plate 64 is one process of the manufacturing method of the metal plate 64. However, the present invention is not limited to this, and the inspection process of the metal plate 64 may be carried out in the equipment for implementing the manufacturing method of the vapor deposition mask 20. In other words, the inspection process of the metal plate 64 may be one process of the manufacturing method of the vapor deposition mask 20.

[0136] Further, in the above-described present embodiment, the depression correction volume density on the surface of the metal plate 64 before the through hole 25 is formed is 15000 μm 3 / mm 2 The following example was shown. In the metal plate 64 after the through hole 25 is formed, that is, in the metal plate 21 of the vapor deposition mask 20, similarly, the depression correction volume density on the surface is 15000 μm 3 / mm 2The following may be the case. As described above, during the etching process, the portion of the metal plate 64 where the through holes 25 are not formed is covered by the resist pattern. Therefore, in the portion of the metal plate 21 of the vapor deposition mask 20 that is located in the ear portions 17a, 17b and the peripheral region 23, there may be a depression 64c equivalent to the metal plate 64 before the through holes 25 are formed. Accordingly, by setting a part of the surface of the metal plate 21 of the vapor deposition mask 20 in the ear portions 17a, 17b and the peripheral region 23 as the inspection region and performing the above-described inspection process in consideration of the volume of the depression 64c, it is possible to calculate the depression correction volume density on the surface of the metal plate 21 of the vapor deposition mask 20.

[0137] Another aspect of the present disclosure will be described.

[0138] One embodiment of the present disclosure is a method for manufacturing a metal plate for manufacturing a vapor deposition mask, the metal plate having a plurality of depressions located on the surface of the metal plate, the manufacturing method including an inspection step of determining the quality of the metal plate based on the total volume of the plurality of depressions located in a part of the surface.

[0139] In the method for manufacturing a metal plate according to one embodiment of the present disclosure, the inspection step may include a calculation step of calculating a depression correction volume density by dividing the total volume of the portions of the plurality of depressions that are separated from the surface by a correction distance or more in the thickness direction of the metal plate by the area of the part of the surface, and a determination step of determining that the metal plate is good when the depression correction volume density is equal to or less than a first threshold value. In this case, the determination step may determine that the metal plate is good when the depression correction volume density is equal to or more than a second threshold value and equal to or less than the first threshold value.

[0140] In the method for manufacturing a metal plate according to an embodiment of the present disclosure, the inspection step may include a calculation step of calculating a depression correction volume density by dividing the total volume of portions of the plurality of depressions that are separated from the surface by a correction distance or more in the thickness direction of the metal plate by the area of the part of the surface, and a sorting step of sorting the metal plates for which the depression correction volume density is equal to or less than a first threshold value. In this case, the sorting step may sort the metal plates for which the depression correction volume density is equal to or greater than a second threshold value and equal to or less than the first threshold value.

[0141] In the method for manufacturing a metal plate according to an embodiment of the present disclosure, the correction distance may be 0.2 μm.

[0142] In the method for manufacturing a metal plate according to an embodiment of the present disclosure, the first threshold value may be 15000 μm 3 / mm 2 Also, the second threshold value may be 10 μm 3 / mm 2

[0143] In the method for manufacturing a metal plate according to an embodiment of the present disclosure, the calculation step may include a measurement step of measuring the depth of the depression at each position of the part of the surface.

[0144] In the method for manufacturing a metal plate according to an embodiment of the present disclosure, the depth of the depression may be measured by a laser microscope in the measurement step.

[0145] In the method for manufacturing a metal plate according to an embodiment of the present disclosure, the area of the part of the surface may be 0.1 mm 2 or more.

[0146] ​One embodiment of the present disclosure is a metal plate for manufacturing a vapor deposition mask. The metal plate has a plurality of depressions located on the surface of the metal plate. When the sum of the volumes of the portions of the plurality of depressions located on a part of the surface and separated from the surface by 0.2 μm or more in the thickness direction of the metal plate is referred to as the depression correction volume, the depression correction volume density calculated by dividing the depression correction volume by the area of the part of the surface is 15000 μm 3 / mm 2 or less. The depression correction volume is calculated based on the results of measuring the depth of the depressions at each position of the part of the surface with a laser microscope, and the area of the part of the surface is 0.1 mm 2 or more. It is a metal plate.

[0147] In the metal plate according to one embodiment of the present disclosure, the depression correction volume density may be 10 μm 3 / mm 2 or more.

[0148] In the metal plate according to one embodiment of the present disclosure, the metal plate may be made of an iron alloy containing nickel.

[0149] One embodiment of the present disclosure is a method for manufacturing a vapor deposition mask in which a plurality of through holes are formed. The method includes a step of preparing a metal plate manufactured by the method for manufacturing a metal plate described above, or the metal plate described above, and a processing step of etching the metal plate to form the through holes in the metal plate. It is a method for manufacturing a vapor deposition mask.

[0150] One embodiment of the present disclosure is a vapor deposition mask, which includes a metal plate having a plurality of depressions located on the surface, and a plurality of through holes formed in the metal plate. When the sum of the volumes of the portions of the plurality of depressions located on a part of the surface and separated from the surface by 0.2 μm or more in the thickness direction of the metal plate is referred to as the depression correction volume, the depression correction volume density calculated by dividing the depression correction volume by the area of the part of the surface is 15000 μm 3 / mm 2It is as follows, and the depression correction volume is calculated based on the result of measuring the depth of the depression at each position of the part of the surface with a laser microscope. The area of the part of the surface is 0.1 mm 2 or more, and it is an evaporation mask.

[0151] In the evaporation mask according to an embodiment of the present disclosure, the depression correction volume density may be 10 μm 3 / mm 2 or more.

Example

[0152] 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 descriptions of the following examples as long as the gist thereof is not exceeded.

[0153] (First inspection example) First, a base material made of a ferroalloy containing 36% by mass of nickel and the balance of iron and inevitable impurities was prepared. Next, by performing the above-described rolling process, slitting process, and annealing process on the base material, two types of coils (hereinafter also referred to as the first sample and the second sample) in which a long metal plate having a thickness of 15 μm was wound were manufactured. Similarly, seven types of coils (hereinafter also referred to as the third sample to the tenth sample) in which a long metal plate having a thickness of 20 μm was wound were manufactured.

[0154] Subsequently, the above-described inspection process for inspecting the undulating state of the surface of each sample was performed. First, the sample was cut out at the center in the width direction of each sample to prepare a test piece having a square shape with a side of 5 cm. Subsequently, a measurement process of measuring the surface position at each pixel 713 of the inspection region 711 of the test piece was performed using a laser microscope. As the laser microscope, a laser microscope VK-X200 series manufactured by Keyence Corporation was used.

[0155] The settings of the laser microscope when measuring the surface position of the test piece were as follows. · Laser light: Blue (wavelength 408 nm) · Objective lens: 50x · Optical zoom: 1.0x · Measurement mode: Surface shape · Measurement size: Standard (1024 × 768) · Measurement quality: High speed · RPD: Yes · Test piece fixing method: Place on a KOKUYO magnetic sheet RPD is the abbreviation of Real Peak Detection. "RPD Yes" means that the method of measuring the position of the surface of the test piece by detecting the peak of the reflected light of the laser beam is adopted.

[0156] The area of the inspection area 711 will be described. Regarding the first to fourth samples and the seventh to tenth samples, nine regions (images) measured under the above-mentioned setting of "standard (1024 × 768)" were connected to form the inspection area 711. In this case, the area U1 of the inspection area 711 was 0.35 mm 2 It was. Also, regarding the fifth and sixth samples, four regions (images) measured under the above-mentioned setting of "standard (1024 × 768)" were connected to form the inspection area 711. In this case, the area U1 of the inspection area 711 was 0.175 mm 2 It was.

[0157] Subsequently, based on the measurement results, a processing step of calculating the depression correction volume V1 and the depression correction volume density V2 on the surface of the test piece was performed. First, using the function of [reference plane setting] of the laser microscope, the above-mentioned reference plane RP was calculated based on the least squares method. At this time, the entire area was targeted without specifying a region. Other settings of the laser microscope are as follows. [Surface shape correction] Yes, correction method: waviness removal, correction strength: 5 [Smoothing] Size: 3 × 3, type: simple average [Height cut-off level] Medium

[0158] Subsequently, based on the measurement results of the surface positions of the test pieces obtained from the samples and the calculation results of the reference plane RP, the depression correction volume V1 and the depression correction volume density V2 of each test piece were calculated. At this time, the correction distance dC between the reference plane RP and the correction plane CP was set to 0.2 μm. The calculation results of the depression correction volume density V2 are shown in FIG. 29.

[0159] Next, the dimensional accuracy of the pattern when the sheet-like metal plates 21 cut out from each of the above samples were etched to form the patterns of the concave portions and the rib portions on each metal plate 21 was evaluated. FIG. 30 is a plan view showing an example of the patterns of the concave portions 81 and the rib portions 82 formed on each metal plate 21. Further, FIG. 31 is a cross-sectional view of the metal plate 21 shown in FIG. 30. In the example shown in FIGS. 30 and 31, the metal plate 21 was etched to form the concave portions 81 so that the rib portions 82 extending along the first direction D1 remained on the metal plate 21. The design values of the dimension Z1 of the concave portion 81 and the dimension Z2 of the rib portion 82 in the direction orthogonal to the direction in which the rib portion 82 extends (here, the rolling direction D1) (here, the width direction D2) were each 30 μm.

[0160] Subsequently, the width of the rib portion 82 formed on each metal plate 21 was measured using a laser microscope. Specifically, the width of the rib portion 82 was measured at a total of 25 locations at intervals of 2 μm along the direction in which the rib portion 82 extends (here, the first direction D1). Further, a value obtained by multiplying the standard deviation of the measurement results of the width of the rib portion 82 at 25 locations by 3 (hereinafter, also referred to as 3σ(D1)) was calculated. The values of 3σ(D1) for the metal plates 21 cut out from each sample are shown together with FIG. 29 described above.

[0161] As the laser microscope, a laser microscope manufactured by Keyence Corporation having a measurement unit and a control unit was used. The model number of the measurement unit is VK-X160, and the model number of the control unit is VK-X150.

[0162] The settings of the laser microscope when measuring the width of the rib portion 82 were as follows. · Brightness: 7140 · Measurement mode: Surface shape · Measurement size: High definition (2048×1536) ·Measurement quality: High precision ·APERTURE SHUTTER: Open ·LASER SUTTER: Open ·Objective lens: 100x ·Optical zoom: 1.0x ·Measurement: Reflection measurement ·Width measurement repeatability accuracy: 3σ = 0.03 μm

[0163] Next, the sheet-like metal plates 21 cut out from each of the above samples were etched in a pattern different from the example shown in FIG. 30 to form the patterns of the concave portions 81 and the rib portions 82 on each metal plate 21. Specifically, as shown in FIG. 32, the metal plate 21 was etched to form the concave portions 81 so that the rib portions 82 extending along the second direction D2 remained on the metal plate 21. Subsequently, the widths of the rib portions 82 formed on each metal plate 21 were measured using a laser microscope. Specifically, the widths of the rib portions 82 were measured at a total of 25 locations at intervals of 2 μm along the direction in which the rib portions 82 extend (here, the second direction D2). Also, a value obtained by multiplying the standard deviation of the width measurement results of the rib portions 82 at 25 locations by 3 (hereinafter, also referred to as 3σ(D2)) was calculated. The values of 3σ(D2) in the metal plates 21 cut out from each sample are shown together with FIG. 29 described above.

[0164] Also, for the metal plates 21 cut out from each sample, the average value 3σ(ave) of the above-mentioned 3σ(D1) and 3σ(D2) was calculated. The values of 3σ(ave) in the metal plates 21 cut out from each sample are shown together with FIG. 29 described above.

[0165] Subsequently, the correlation coefficient R 2 between the depression correction volume density V2(0.2 μm) calculated for each sample and 3σ(ave) of the width of the rib portion 82 2 was obtained. As a result, the correlation coefficient R

[0166] (Second to fifth inspection examples) Except for changing the correction distance dC between the reference plane RP and the correction plane CP, in the same manner as in the case of the first inspection example described above, the undulating state of the surfaces of the first to tenth samples described above was inspected based on the depression correction volume density V2. Specifically, in the second inspection example, the correction distance dC was set to 0.1 μm to calculate the depression correction volume density V2(0.1 μm). Also, in the third inspection example, the correction distance dC was set to 0.3 μm to calculate the depression correction volume density V2(0.3 μm). Also, in the fourth inspection example, the correction distance dC was set to 0.4 μm to calculate the depression correction volume density V2(0.4 μm). Also, in the fifth inspection example, the correction distance dC was set to 0.5 μm to calculate the depression correction volume density V2(0.5 μm). The calculation results of the depression correction volume densities V2(0.1 μm), V2(0.3 μm), V2(0.4 μm), and V2(0.5 μm) for each sample are shown in FIG. 34 together with the above-described depression correction volume density V2(0.2 μm).

[0167] Subsequently, the correlation coefficient R between the depression correction volume density V2(0.1 μm) calculated for each sample and 3σ(ave) of the width of the rib portion 82 2 was determined. As a result, the correlation coefficient R 2 was 0.0136. FIG. 35 is a scatter diagram showing the correlation between the depression correction volume density V2(0.1 μm) and 3σ(ave) of the width of the rib portion 82.

[0168] Also, the correlation coefficient R between the depression correction volume density V2(0.3 μm) calculated for each sample and 3σ(ave) of the width of the rib portion 82 2 was determined. As a result, the correlation coefficient R 2 was 0.6653. FIG. 36 is a scatter diagram showing the correlation between the depression correction volume density V2(0.3 μm) and 3σ(ave) of the width of the rib portion 82.

[0169] Also, the correlation coefficient R between the depression correction volume density V2(0.4 μm) calculated for each sample and 3σ(ave) of the width of the rib portion 82 2 was determined. As a result, the correlation coefficient R 2It was 0.4811. FIG. 37 is a scatter diagram showing the correlation between the recess correction volume density V2(0.4 μm) and the 3σ(ave) of the width of the rib portion 82.

[0170] Also, the correlation coefficient R between the recess correction volume density V2(0.5 μm) and the 3σ(ave) of the width of the rib portion 82, calculated for each sample 2 was obtained. As a result, the correlation coefficient R 2 was 0.3791. FIG. 38 is a scatter diagram showing the correlation between the recess correction volume density V2(0.5 μm) and the 3σ(ave) of the width of the rib portion 82.

[0171] According to the first inspection example, by inspecting the undulating state of the surface of the metal plate based on the volume of the recesses, an index having a high correlation with the dimensional accuracy of the rib portion 82 formed by etching could be obtained.

[0172] Also, as can be seen from the comparison between the above-described first inspection example and the second to fifth inspection examples, according to the first inspection example, by setting the correction distance dC between the reference plane RP and the correction plane CP to 0.2 μm, an index having a high correlation with the dimensional accuracy of the rib portion 82 formed by etching could be obtained.

[0173] In the second inspection example where the correction distance dC was set to 0.1 μm, since the correction distance dC was too small, not only specific recesses that had a large impact on the dimensional accuracy of the rib portion 82 but also recesses that had almost no impact on the dimensional accuracy of the rib portion 82 were detected. As a result, it is considered that the correlation coefficient decreased. In the third to fifth inspection examples where the correction distance dC was set to 0.3 μm or more, since the correction distance dC was too large, when evaluating a relatively smooth metal plate with a small density of recesses, the density and dimensional differences of the recesses were not appropriately reflected in the recess correction volume density V2. As a result, it is considered that the correlation coefficient decreased.

Explanation of Signs

[0174] 10 Evaporation mask device 15 Frame 20 Evaporation mask 21 Metal plate 22 Effective area 23 Peripheral area 25 Through-hole 30 First recess 31 Wall surface 35 Second recess 36 Wall surface 41 Connection part 41a Chip part 43 Top part 50 Intermediate product 64 Long metal plate 64c Depression 65a First resist pattern 65b Second resist pattern 65c First resist film 65d Second resist film 711 Inspection area 712 Unit area 713 Pixel 72 Processing device 73 Separation device 80 Sample 81 Recess 82 Rib part 90 Evaporation device 92 Organic EL substrate 98 Evaporation material

Claims

[Claim 1] A metal plate for manufacturing a deposition mask, When a plurality of samples of the metal plate are evaluated by the following evaluation method, the correlation coefficient when the corrected distance is 0.2 μm is higher than the correlation coefficient when the corrected distance is 0.1 μm and is also higher than the correlation coefficient when the corrected distance is 0.3 μm; When a plurality of samples of the metal plate are evaluated by the following evaluation method, the dent-corrected volume density when the correction distance is 0.2 μm is 12000 μm ３ / mm ２ is as follows: The evaluation method includes: A step of calculating a correlation coefficient between a plurality of dent-corrected volume densities calculated based on a plurality of correction distances and a standard deviation of the width of the rib portion, the rib portion is a portion of the surface of the metal plate that is located between a plurality of recesses formed by etching the metal plate and remains unetched; the metal plate has a plurality of depressions located on a surface of the metal plate; The surface is 0.1 mm ２ a test area having an area of ​​at least one of the plurality of recesses, the test area being located in the test area; each of the plurality of dent-corrected volume densities is calculated by dividing a dent-corrected volume corresponding to each of the plurality of corrected distances by an area of ​​the inspection region; the dent correction volume is a sum of volumes of portions of the part of the plurality of dents located in the inspection area that are apart from the surface in a thickness direction of the metal plate by the correction distance or more, The volume is calculated based on a result of measuring a depth of the part of the plurality of recesses using a laser microscope.

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