Metal mask and production method of same

Abstract

Provided is a metal mask comprising at least one perforated region and a peripheral region. The overall outline of the at least one perforated region has two short sides in the width direction and two long sides in the longitudinal direction. When Xn is the length of the outline in the longitudinal direction of the perforated region at an arbitrary position n when the two short sides are divided into N in the width direction (where 1≤n≤N+1) and Ym is the length of the outline in the width direction of the perforated region at an arbitrary position m when the two long sides are divided into M in the longitudinal direction (where 1≤m≤M+1), Xn and Ym satisfy the following expressions (1) and (2). (1): Xn≤Xn+1; (2): Ymax-Ymin≤12.5 μm, where Ymax is the maximum value of Ym (1≤m≤M+1) and Ymin is the minimum value of Ym (1≤m≤M+1).

Description

Metal mask and its manufacturing method

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

[0002] The pixels of each color of an organic EL display device are formed by depositing a pixel-forming material on a substrate by vapor deposition using a metal mask. When a vapor deposition material is deposited on a substrate using a metal mask, it is necessary to deposit the vapor deposition material on the substrate with high precision. For example, Patent Document 1 discloses a method for determining the quality of a vapor deposition mask, which can improve the positional accuracy of through holes when the metal mask is tensioned and placed on a frame.

[0003] WO2020 / 012862

[0004] As the size of organic EL display devices has increased from relatively small displays such as those used in smartphones to relatively large displays such as those used in tablets and mobile PCs, the metal masks used to manufacture these displays have also become longer and wider. Such large metal masks require positional accuracy of the through holes over a wider range when the metal mask is tensioned and mounted on a frame.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a metal mask having excellent positional accuracy of through holes when stretched, and a method for manufacturing the same.

[0006] A metal mask according to an embodiment of the present disclosure has one or more perforated regions and a peripheral region, wherein the overall outline of the one or more perforated regions has two short sides in the width direction and two long sides in the longitudinal direction, wherein when the two short sides are divided into N in the width direction, the length of the outline of the perforated region in the longitudinal direction at any position n (where 1≦n≦N+1) is defined as Xn, and when the two long sides are divided into M in the longitudinal direction, the length of the outline of the perforated region in the width direction at any position m (where 1≦m≦M+1) is defined as Ym, where Xn and Ym satisfy the following formulas (1) and (2): Xn≦Xn+1 (1) Ymax-Ymin≦12.5 μm (2) Ymax: maximum value of Ym (1≦m≦M+1) Ymin: minimum value of Ym (1≦m≦M+1)

[0007] A method for manufacturing a metal mask according to one embodiment of the present disclosure includes: a step of preparing a metal plate; and an etching step of forming the metal mask by etching the metal plate, the metal mask having one or more perforated regions and a surrounding region, wherein the overall outline of the one or more perforated regions has two short sides in the width direction and two long sides in the longitudinal direction, and when the two short sides are divided into N in the width direction, the length of the outline of the perforated region in the longitudinal direction at any position n (where 1≦n≦N+1) is defined as Xn, and when the two long sides are divided into M in the longitudinal direction, the length of the outline of the perforated region in the width direction at any position m (where 1≦m≦M+1) is defined as Ym, where Xn and Ym satisfy the following formulas (1) and (2). Xn≦Xn+1 (1) Ymax-Ymin≦12.5 μm (2) Ymax: Maximum value of Ym (1≦m≦M+1) Ymin: Minimum value of Ym (1≦m≦M+1)

[0008] At least one embodiment of the present disclosure aims to provide a metal mask that is relatively large but has excellent positional accuracy of through holes when stretched, and a method for manufacturing the same.

[0009] 3A is a plan view showing a metal mask according to an embodiment of the present disclosure. FIG. 1B is a schematic diagram showing the overall outline of the perforated region of the metal mask of FIG. 1A. FIG. 1C is a schematic diagram showing the outline of each perforated region of the metal mask of FIG. 1A. FIG. 2D is a top view showing one aspect of the perforated region when viewed from the second surface side. FIG. 2A is a cross-sectional view taken along line II' in FIG. 2A. FIG. 2D is a cross-sectional view taken along line II-II' in FIG. 2A. FIG. 2D is a cross-sectional view taken along line III-III' in FIG. 2A. FIG. 2D is a perspective view showing one aspect of the perforated region when viewed from the second surface side. FIG. 3A is a perspective view of a metal plate used in fabricating a metal mask. FIG. 3B is a perspective view of an exposure step for the metal plate shown in FIG. 3A. FIG. 3C is a perspective view of an etching step for the metal plate shown in FIG. 3A. FIG. 3D is a top view of a metal mask in which distortion due to a corrugated shape is reflected. FIG. 3E is a top view of a state in which tension is applied to the metal mask in the longitudinal direction. FIG. 3F is a schematic diagram for explaining an example of a method for manufacturing a metal mask. FIG. 3G is a view showing an example of a step of forming a resist film on a metal plate. FIG. 3H is a view showing an example of a step of patterning the resist film. FIG. 3I is a view showing an example of a first surface etching step in the perforated region. FIG. 3II is a view showing an example of a second surface etching step in the perforated region. 1 is a diagram illustrating a metal mask apparatus according to an embodiment of the present disclosure; 2 is a cross-sectional view illustrating a vapor deposition apparatus according to an embodiment of the present disclosure;

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that in the drawings attached to this specification, the scale and aspect ratios may be appropriately changed and exaggerated from those of the actual objects for the sake of convenience in illustration and understanding.

[0011] In this specification and / or drawings, unless otherwise specified, the following interpretations shall be made.

[0012] Terms that refer to a material that is the basis of a certain structure do not necessarily need to be distinguished by differences in name alone. For example, terms such as "substrate," "base material," "plate," "sheet," or "film" fall under the above description.

[0013] Terms and / or numerical values ​​that represent shapes and / or geometric conditions need not be bound by strict meanings and may be interpreted as including a range within which similar functions may be expected. For example, "parallel" and / or "orthogonal" fall under the above terms. Also, "length value" and / or "angle value" fall under the above numerical values.

[0014] When a certain configuration is expressed as being "above," "below," "upper," "lower," "above," or "below" another configuration, this may include a configuration in which the certain configuration is in direct contact with the other configuration, and a configuration in which another configuration is included between the certain configuration and the other configuration. In other words, a configuration in which another configuration is included between the certain configuration and the other configuration may be expressed as a configuration indirectly in contact with the other configuration. Furthermore, the expressions "above," "upper side," or "above" are interchangeable with the expressions "below," "lower side," or "below." In other words, the up-down direction may be reversed.

[0015] When the same or similar symbols are used to denote identical parts and / or parts having similar functions, repeated descriptions may be omitted. Also, the dimensional ratios in the drawings may differ from the actual ratios. Also, some of the configurations of the embodiments may be omitted from the drawings.

[0016] One or more embodiments may be combined with one or more modified embodiments as long as no contradictions arise. Also, one or more embodiments may be combined with each other as long as no contradictions arise. Also, one or more modified embodiments may be combined with each other as long as no contradictions arise.

[0017] When a plurality of steps are disclosed for a method such as a manufacturing method, other steps that are not disclosed may be performed between the disclosed steps. Furthermore, the order of the steps is not limited to the extent that no contradiction occurs.

[0018] Numerical ranges expressed with the symbols "to" and / or "-" include the numerical values ​​before and after the symbols "to" and / or "-". For example, a numerical range expressed as "34 to 38% by mass" is the same as a numerical range expressed as "34% by mass or more and 38% by mass or less".

[0019] For the numerical values ​​described in this disclosure, a numerical range may be defined by combining any one of a plurality of upper limit candidate values ​​with any one of a plurality of lower limit candidate values. In addition, even if not specifically mentioned, a numerical range may be defined by combining any two of a plurality of upper limit candidate values, or a numerical range may be defined by combining any two of a plurality of lower limit candidate values.

[0020] An embodiment of the present disclosure will be described in the following paragraphs. The embodiment of the present disclosure is an example of an embodiment of the present disclosure. The present disclosure is not construed as being limited to only the embodiment of the present disclosure.

[0021] The metal mask of the present disclosure can be used for various applications. For example, without limitation, the metal mask of the present disclosure can be used as a metal mask used to pattern an organic material into a desired pattern on a substrate in the manufacture of an organic electroluminescent (EL) display device. Such a metal mask is also called a deposition mask. Furthermore, the metal mask of the present disclosure can enable high-pixel-density patterning. Organic EL display devices that can be manufactured include displays for smartphones, televisions, and the like, as well as devices for displaying or projecting images and videos to express virtual reality (VR) and augmented reality (AR).

[0022] Unless otherwise specified in the present specification and drawings, an example of a metal mask used in manufacturing an organic EL display device and a manufacturing method thereof will be described as one embodiment of the present disclosure.

[0023] A first aspect of the present disclosure is a metal mask having one or more perforated regions and a surrounding region, wherein the overall outline of the one or more perforated regions has two short sides in the width direction and two long sides in the longitudinal direction, and when the two short sides are divided into N in the width direction, the length of the outline of the perforated region in the longitudinal direction at any position n (where 1≦n≦N+1) is taken as Xn, and when the two long sides are divided into M in the longitudinal direction, the length of the outline of the perforated region in the width direction at any position m (where 1≦m≦M+1) is taken as Ym, where Xn and Ym satisfy the following formulas (1) and (2): Xn≦Xn+1 (1) Ymax - Ymin≦12.5 μm (2) Ymax: maximum value of Ym (1≦m≦M+1) Ymin: minimum value of Ym (1≦m≦M+1).

[0024] A second aspect of the present disclosure is the metal mask according to the first aspect, wherein X1 may be 700 mm or more.

[0025] A third aspect of the present disclosure is the metal mask of the first or second aspect, wherein Ymin may be 200 mm or more.

[0026] A fourth aspect of the present disclosure is the metal mask of any one of the first to third aspects described above, wherein (Ymin / X1) may be 0.3 or more.

[0027] A fifth aspect of the present disclosure is a metal mask according to any one of the first to fourth aspects described above, wherein the metal mask has a plurality of perforated regions, and each of the plurality of perforated regions has an outer shape having two short sides in the width direction and two long sides in the longitudinal direction, and in any one of the perforated regions A, when the two short sides are divided into I parts in the width direction, the length of the outer shape of the perforated region in the longitudinal direction at any position Ai (where 1≦i≦I+1) is taken as AXi, and when the two long sides are divided into J parts in the longitudinal direction, the length of the outer shape of the perforated region in the width direction at any position Aj (where 1≦j≦J+1) is taken as AYj, where AXi and AYj may satisfy the following formulas (3) and (4). AXi≦AXi+1 (3) AYmax-AYmin≦12.5 μm (4) AYmax: maximum value of AYj (1≦j≦J+1) AYmin: minimum value of AYj (1≦j≦J+1)

[0028] A sixth aspect of the present disclosure comprises: a step of preparing a metal plate; and an etching step of forming a metal mask by etching the metal plate, the metal plate having one or more perforated regions and a peripheral region, wherein the overall outline of the one or more perforated regions has two short sides in the width direction and two long sides in the longitudinal direction, and when the two short sides are divided into N in the width direction, the length of the outline of the perforated region in the longitudinal direction at any position n (where 1≦n≦N+1) is taken as Xn, and when the two long sides are divided into M in the longitudinal direction, the length of the outline of the perforated region in the width direction at any position m (where 1≦m≦M+1) is taken as Ym, Xn and Ym satisfy the following formulas (1) and (2): Xn≦Xn+1 (1) Ymax-Ymin≦12.5 μm (2) Ymax: maximum value of Ym (1≦m≦M+1). Ymin: minimum value of Ym (1≦m≦M+1) A method for manufacturing a metal mask.

[0029] The metal mask 20 of the present disclosure will be described in detail below.

[0030] The metal mask 20 of the present disclosure has a perforated region 22 and a peripheral region 23. The perforated region 22 is a region in which a plurality of through holes 25 are formed in any shape and any pattern. The peripheral region 23 is a region located around the perforated region 22.

[0031] 1A shows a plan view of the second surface 20b side of a metal mask 20 according to an embodiment of the present disclosure. As shown in FIG. 1A, the metal mask 20 may have a substantially rectangular outline in plan view. Note that in this disclosure, "plan view" refers to viewing the metal mask 20 from a surface along the plate surface of the metal mask 20.

[0032] The metal mask 20 of the present disclosure has one or more perforated regions 22. Specifically, the metal mask 20 of the present disclosure may have multiple perforated regions 22 arranged in a row at predetermined intervals along a direction parallel to the longitudinal direction D2, as shown in Figure 1A, or may have a single perforated region 22 along the longitudinal direction D2. Such a metal mask 20 is also referred to as an elongated or stick-shaped metal mask.

[0033] In the metal mask 20 of the present disclosure, one perforated region 22 may be configured to correspond to one organic EL display device. For example, as shown in FIG. 1A , the metal mask 20 may have a plurality of perforated regions 22 arranged in a line at predetermined intervals along the longitudinal direction D2. In FIG. 1A , a peripheral region 23 is positioned around each perforated region 22. Use of such a metal mask 20 makes it possible to vapor-deposit multiple organic EL display devices onto the substrate 92. Alternatively, one perforated region 22 may be configured to correspond to multiple organic EL display devices.

[0034] The material for forming the metal mask 20 is not particularly limited, but examples thereof include iron alloys containing nickel, iron alloys containing chromium such as stainless steel, nickel, and nickel-cobalt alloys.

[0035] Among these, an iron alloy containing nickel is preferable. By using an iron alloy containing nickel, the thermal expansion coefficient of the metal mask 20 can be made equal to the thermal expansion coefficient of the frame 15 and the thermal expansion coefficient of the substrate 92 (see FIG. 6 ). This makes it possible to suppress misalignment caused by differences in dimensional changes among the metal mask 20, the frame 15, and the substrate 92 during the vapor deposition process. Therefore, it is possible to suppress a decrease in the dimensional accuracy and positional accuracy of the vapor deposition material 98 attached to the substrate 92 caused by misalignment.

[0036] The iron alloy containing nickel is not particularly limited, but examples thereof include iron alloys containing 0% by mass or more and 54% by mass or less of nickel, such as a super invar material containing 30% by mass or more and 34% by mass or less of nickel and further containing cobalt, an invar material containing 34% by mass or more and 38% by mass or less of nickel, and a low-thermal expansion Fe—Ni-based plated alloy containing 48% by mass or more and 54% by mass or less of nickel.

[0037] 2A to 2E, the surfaces of the metal mask 20 of the present disclosure will be described. The metal mask 20 of the present disclosure has a first surface 20a and a second surface 20b as its front and back surfaces.

[0038] Fig. 2A shows a top view illustrating one aspect of the perforated region when viewed from the second surface side, and Fig. 2E shows a perspective view illustrating one aspect of the range S1 of the perforated region when viewed from the second surface side. Fig. 2B is a cross-sectional view taken along line II' in Fig. 2A. Fig. 2C is a cross-sectional view taken along line II-II' in Fig. 2A. Fig. 2D is a cross-sectional view taken along line III-III' in Fig. 2A.

[0039] In the present disclosure, the first surface 20a and the second surface 20b of the metal mask 20 are distinguished by the diameter of the through holes 25 on the front and back surfaces of the perforated region 22. Specifically, as shown in FIGS. 2B to 2D , the first surface 20a refers to the surface in the perforated region 22 where the opening area of ​​the through holes 25 is small, and the second surface 20b refers to the surface where the opening area of ​​the through holes 25 is large. Note that, as shown in FIG. 2E and other figures, when the second wall surfaces 36 of the second recesses 35 of adjacent through holes 25 meet on the second surface 20b, the area S3 enclosed by the ridge line 33 surrounding one through hole 25 may be considered the opening of the through hole 25. In this case, the area enclosed by the ridge line 33 is the opening area.

[0040] From the viewpoint of the vapor deposition process, the first surface 20a may be the surface of the metal mask 20 that faces the substrate 92 when the metal mask device 10 is housed in the vapor deposition device 90 (see FIG. 6 ). The second surface 20b may be the surface of the metal mask 20 that faces the crucible 94 that holds the vapor deposition material 98 when the metal mask device 10 is housed in the vapor deposition device 90 (see FIG. 6 ).

[0041] Next, the pattern of the deposition layer to be attached to the substrate 92 and the pattern of the through holes 25 in the perforated region 22 of the metal mask 20 for forming the deposition layer will be described.

[0042] The through-holes 25 penetrate the metal mask 20 from the first surface 20a to the second surface 20b in the thickness direction N. In the vapor deposition process, the vapor deposition material 98 passes through the through-holes 25 and is deposited on the substrate 92.

[0043] The arrangement pattern of the through holes 25 in the perforated region 22 corresponds to the pattern in which the vapor deposition material 98 is applied, and the rectangular arrangement of the through holes 25 is formed in accordance with the pattern of the vapor deposition layer of each color, such as red R, green G, or blue B. Therefore, when the application pattern differs depending on the type of vapor deposition material 98, a metal mask 20 having a different arrangement pattern of the through holes 25 may be used depending on the type of vapor deposition material 98. For example, different metal masks 20 may be used to sequentially vapor-deposit the red vapor deposition material 98, the green vapor deposition material 98, and the blue vapor deposition material 98 onto the substrate 92.

[0044] Furthermore, when the pattern for depositing the vapor deposition material 98 is the same regardless of color, for example, when the pattern for depositing red R and blue B is the same, the same metal mask 20 may be used. In this case, the metal mask 20 and the substrate 92 may be moved relative to each other, so that the red vapor deposition material 98, the green vapor deposition material 98, and the blue vapor deposition material 98 are deposited in the same pattern in that order using one metal mask 20.

[0045] Next, the aspects of the through-holes 25 in the perforated region 22 will be described in more detail with reference to FIGS. 2A to 2E.

[0046] In the present disclosure, as shown in FIGS. 2A and 2E, the perforated region 22 may include a plurality of through holes 25 and a plurality of ridges 33 on at least the second surface 20b.

[0047] 2A to 2E, the through hole 25 has a first recess 30 formed in the first surface 20a, a second recess 35 formed in the second surface 20b, and a circumferential connecting portion 41 connecting the first recess 30 and the second recess 35. The through hole 25 is formed by connecting the first recess 30 on the first surface 20a side with the second recess 35 on the second surface 20b side. The portion where the first recess 30 and the second recess 35 communicate is called the connecting portion 41. The first wall surface 31 of the first recess 30 and the second wall surface 36 of the second recess 35 are connected via the circumferential connecting portion 41.

[0048] The area of ​​the first recess 30 in a plan view may gradually decrease from the first surface 20 a to the second surface 20 b. The area of ​​the second recess 35 in a plan view may gradually decrease from the second surface 20 b to the first surface 20 a. The first recess 30 may be configured as a recess with a smaller diameter than the second recess 35.

[0049] At the connection portion 41, the direction in which the wall surface of the through-hole 25 expands changes discontinuously. Generally, at the connection portion 41, the opening area of ​​the through-hole 25 in plan view becomes smallest.

[0050] 2A , the through hole 25 has a connection portion 41 that is approximately square in plan view. The connection portion 41 of the through hole 25 is the narrowest part of the through hole 25 and defines the location where the deposition material 98 adheres to the substrate 92. Note that although the connection portion 41 of the through hole 25 is shown as a rectangle that is approximately close to a square in FIG. 2A , the shape is not limited thereto, and the through hole 25 may be a polygon such as a triangle, pentagon, hexagon, or octagon, or may be a circular shape such as a circle or an ellipse.

[0051] The through holes 25 may be formed in any desired pattern other than the pattern exemplified in FIG. 2A . For example, the through holes 25 may be arranged in a grid pattern at a predetermined pitch along two intersecting directions. The through holes 25 may also be arranged in a staggered pattern at a predetermined pitch along two intersecting directions, or in any other pattern. In any pattern, the through holes 25 are arranged in any regular pattern in accordance with the patterns of the vapor deposition layers of each color, such as red (R), green (G), and blue (B), and therefore can be said to have a row of through holes aligned on any straight line L. Note that the two directions may or may not coincide with the longitudinal direction D2 or width direction D1 of the metal mask 20.

[0052] Furthermore, there are no particular limitations on the pitch of the through holes 25 in the perforated region 22. For example, when the metal mask 20 is used to fabricate a display (approximately 0.5 inches to 32 inches) for a mobile phone, digital camera, or the like, the pitch of the through holes 25 may be approximately 20 μm to 254 μm in both the width direction D1 and the longitudinal direction D2.

[0053] 2E , the ridge line 33 is a boundary formed by the joining of the second wall surfaces 36 of the second recesses 35 of adjacent through holes 25. The height of this ridge line 33 is not constant, and may vary in an undulating manner. The height of the ridge line 33 can also be said to be the position of the ridge line 33 in the thickness direction of the metal mask 20. As a general trend, the height of the ridge line 33 changes depending on the distance from the center of the through hole 25, becoming higher as the distance increases and becoming lower as the distance decreases.

[0054] Next, the shape of the metal mask 20 of the present disclosure will be described based on the process for manufacturing the metal mask 20 from the metal plate 51 with reference to Figures 3A to 3E. After that, the shape of the overall outer shape 22T of one or more perforated regions of the present disclosure will be described with reference to Figure 1B.

[0055] Fig. 3A is a perspective view of a metal plate used to fabricate a metal mask. Fig. 3B is a perspective view of an exposure process for the metal plate shown in Fig. 3A, and Fig. 3C is a perspective view of an etching process for the metal plate shown in Fig. 3A. Fig. 3D is a top view of the metal mask reflecting distortion due to the corrugated shape, and Fig. 3E is a top view of the metal mask in a state where tension is applied in the longitudinal direction.

[0056] First, as shown in Fig. 3A, a metal sheet 51 may have a corrugated shape at least partially. Generally, the thinner the metal sheet is rolled to improve the dimensional accuracy of the through hole, the more corrugated the metal sheet becomes. Such a corrugated shape occurs because the length of the metal sheet 51 in the longitudinal direction D2 varies depending on the position in the width direction D1.

[0057] 3B, a first resist film 53a is formed on the first surface 51a of the metal plate 51, and a second resist film 53b is formed on the second surface 51b of the metal plate 51, and then the metal plate 51 is exposed to light. In this exposure process, an exposure mask is brought into close contact with the first resist pattern 53c and the second resist pattern 53d on the metal plate 51 by vacuum suction or the like. Therefore, as shown in FIG. 3B, the corrugated shape of the metal plate 51 is compressed in the exposure process, and the metal plate 51 becomes substantially flat.

[0058] In this flat state, an exposure step is performed and a development step is carried out, whereby a predetermined resist pattern is formed so as to define the outline of the metal mask 20 in the portion indicated by the dashed line in FIG. 3B.

[0059] Next, Figure 3C shows a schematic perspective view of the etching process using the resist pattern. In the etching process, the exposure mask is removed from the metal plate 51, and the corrugation shape is restored to the extent shown in Figure 3A. By performing etching in this state with the corrugation shape restored as shown in Figure 3C, the outer shape 27 of the resulting metal mask 20 reflects the corrugation shape as shown in Figure 3D. Specifically, the outer shape 27 of the metal mask 20 tends to curve toward the side with the larger corrugation shape.

[0060] The distortion caused by the wavy shape is reflected in this way, causing variations in the outer shape of the obtained metal mask 20, and ultimately in the overall outer shape 22T of the perforated region 22. In other words, the overall outer shape 22T of the perforated region 22 may have distortion derived from the wavy shape of the original metal plate 51.

[0061] 3E is a schematic diagram showing the state in which tension is being applied to the metal mask 20 immediately before it is placed on the frame 15. As shown in FIG. 3E, tension is applied to the metal mask 20 in the longitudinal direction D2 by clamps 86 or the like when it is placed on the frame 15. At this time, different tensions may be applied in the width direction D1 so that the longitudinal lengths X1 and XN are approximately the same across the entire outer shape 22T of the perforated region 22. This allows the metal mask 20 to be placed on the frame 15 in a flat state.

[0062] However, even if tension is applied so that the longitudinal length X1 and the length XN are approximately the same, if there is a portion in the width direction D1 where the longitudinal length Xn is a minimum value, as shown in the following formula (5), the positional accuracy of the through holes in that portion may be reduced when the metal mask 20 is placed on the frame 15. Xn-1>Xn<Xn+1 (5)

[0063] In the present disclosure, n refers to any division points arranged in the order of 1, 2, ..., n-1, n, n+1, ..., N from one end to the other end in the width direction D1 when the short sides 22Ta, 22Tb are divided into N parts in the width direction D1. Also, X1, X2, ..., Xn-1, Xn, Xn+1, ..., XN refer to the distances when connecting the division points with the same number (1, 2, ..., n-1, n, n+1, ..., N) on the short sides 22Ta, 22Tb.

[0064] Similarly, m, which will be described later, refers to any division points arranged in the order of 1, 2, ..., m-1, m, m+1, ..., M from one end to the other end in the longitudinal direction D2 when the two long sides 22Tc, 22Td are divided into M parts in the longitudinal direction D2. Furthermore, Y1, Y2, ..., Ym-1, Ym, Ym+1, ..., YM refer to the distances when connecting the division points with the same number (1, 2, ..., m-1, m, m+1, ..., N) on the long sides 22Tc, 22Td.

[0065] Furthermore, even if tension is applied so that the longitudinal length X1 and the length XN are approximately the same, if, for example, there is a large variation in the length in the width direction D1, the positional accuracy of the through holes in that portion may be reduced when the metal mask 20 is placed on the frame 15.

[0066] Therefore, in the metal mask 20 of the present disclosure, as shown in FIG. 1B , when the two short sides 22Ta, 22Tb are divided into N widthwise parts, the overall outer shape 22T of the perforated region 22 is defined by the length Xn of the outer shape 22T in the longitudinal direction D2 of the perforated region 22 at any position n (where 1≦n≦N+1) and the length Ym of the outer shape 22T in the width direction D1 of the perforated region 22 at any position m (where 1≦m≦M+1) when the two long sides 22Tc, 22Td are divided into M widthwise parts.

[0067] In this case, the metal mask 20 of the present disclosure is configured so that Xn and Ym satisfy the following formulas (1) and (2). By defining the overall outer shape 22T of the perforated region 22 in this manner, it is possible to improve the positional accuracy of the through holes when the metal mask 20 is placed on the frame 15. Xn≦Xn+1 (1) Ymax−Ymin≦12.5 μm (2) Ymax: maximum value of Ym (1≦m≦M+1) Ymin: minimum value of Ym (1≦m≦M+1)

[0068] Equation (1) means that the length Xn in the longitudinal direction D2 of the outer shape 22T may increase from the long side 22Tc toward the long side 22Td. In other words, as shown in the following equation (5), the longitudinal length Xn does not take a minimum value. This allows the metal mask 20 to be placed on the frame 15 in a flat state by applying tension so that the longitudinal lengths X1 and XN are approximately the same. This improves the positional accuracy of the through holes when the metal mask 20 is placed on the frame 15. Xn-1>Xn<Xn+1 ... (5)

[0069] From this viewpoint, (XN-X1) is preferably 30 μm or less, 25 μm or less, 20 μm or less, or may be 15 μm or less. The lower limit of (XN-X1) is preferably 1 μm or more, 2.5 μm or more, 5 μm or more, or may be 7.5 μm or more. Furthermore, (XN-X1) is preferably 1 to 30 μm, 2.5 to 25 μm, 5 to 20 μm, or 7.5 to 15 μm. Note that, according to formula (1), XN is the maximum value in the longitudinal direction D2 of the perforated region 22, and X1 is the minimum value. Therefore, (XN-X1) represents the difference between the maximum and minimum values ​​of the length of the outer shape 22T of the perforated region 22 in the longitudinal direction D2.

[0070] From the same viewpoint, (XN-X1) / Yave is preferably 0.070 or less, 0.065 or less, 0.060 or less, or 0.055 or less. The lower limit of (XN-X1) / Yave is preferably 0.015 or more, 0.020 or more, 0.025 or more, or 0.030 or more. Furthermore, (XN-X1) / Yave is preferably 0.015 to 0.070, 0.020 to 0.065, 0.025 to 0.060, or 0.030 to 0.055. Note that Yave refers to the average of Y1, Y2, ..., YM. Therefore, (XN-X1) / Yave refers to the value of (XN-X1) per unit length in the width direction D1 of the perforated region 22.

[0071] Furthermore, formula (2) means that there is little variation in the length Ym of the outer shape 22T in the width direction D1. As shown in Figure 6, when multiple metal masks 20 are placed on the frame 15, it may be difficult to apply tension in the width direction D1. In this regard, because there is little variation in Ym, it is possible to improve the positional accuracy of the through holes when the metal masks 20 are placed on the frame 15 without applying tension.

[0072] From this viewpoint, (Ymax - Ymin) is 12.5 μm or less, preferably 12 μm or less, 11 μm or less, 10 μm or less, 9 μm or less, 8 μm or less, or may be 7 μm or less. The lower limit of (Ymax - Ymin) is preferably 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, or may be 5 μm or more. (Ymax - Ymin) is preferably 1 to 12.5 μm, 2 to 12 μm, 3 to 11 μm, 4 to 10 μm, or may be 5 to 9 μm.

[0073] From the same viewpoint, (Ymax-Ymin) / XN is preferably 0.001 or more, 0.002 or more, 0.004 or more, or 0.006 or more. Furthermore, (Ymax-Ymin) / XN is preferably 0.012 or less, 0.015 or less, 0.018 or less, or 0.020 or less. Furthermore, (Ymax-Ymin) / XN is preferably 0.001 to 0.012, 0.002 to 0.015, 0.004 to 0.018, or 0.006 to 0.020. Note that (Ymax-Ymin) / XN refers to the value of (Ymax-Ymin) per unit length in the longitudinal direction D2 of the perforated region 22.

[0074] The positional accuracy of the through holes tends to decrease when the outer shape 22T of the perforated region 22 is large, particularly when the screen size is larger than that of a tablet, mobile PC, etc. Therefore, in the present disclosure, it is more preferable that the positional accuracy of the through holes be improved when the metal mask 20 is placed on the frame 15 for an outer shape 22T of a predetermined dimension.

[0075] From this viewpoint, X1 may preferably be 600 mm or more, 700 mm or more, 750 mm or more, 800 mm or more, 850 mm or more, or 900 mm or more. Furthermore, X1 may preferably be 1300 mm or less, 1200 mm or less, 1150 mm or less, 1100 mm or less, 1050 mm or less, 1000 mm or less, or 950 mm or less. Furthermore, X1 may preferably be 600 to 1300 mm, 700 to 1200 mm, 750 to 1150 mm, or 800 to 1100 mm.

[0076] Furthermore, Ymin may be preferably 150 mm or more, 200 mm or more, 225 mm or more, 250 mm or more, 275 mm or more, or 300 mm or more. Furthermore, Ymin may be preferably 450 mm or less, 400 mm or less, 375 mm or less, 350 mm or less, or 325 mm or less. Furthermore, Ymin may be preferably 150 to 450 mm, 200 to 400 mm, 225 to 375 mm, 250 to 350 mm, or 275 to 325 mm.

[0077] Similarly, (Ymin) / X1 is preferably 0.10 or more, 0.15 or more, 0.20 or more, 0.25 or more, or may be 0.30 or more. Also, (Ymin) / X1 is preferably 0.55 or less, 0.50 or less, 0.45 or less, 0.40 or less, or 0.35 or less. (Ymin) / X1 is preferably 0.10 to 0.55, 0.15 to 0.50, 0.20 to 0.45, 0.25 to 0.40, or 0.30 to 0.35.

[0078] 1C , the metal mask 20 of the present disclosure may further define the outer shape 22A of each of the perforated regions 22 of the metal mask 20. This can improve the positional accuracy of the through holes when the metal mask 20 is placed on the frame 15.

[0079] Specifically, as shown in Figure 1C, in any perforated area A, when the two short sides 22Aa, 22Ab are divided into I parts in the width direction, the length of the longitudinal outline of the perforated area at any position Ai (where 1≦i≦I+1) is defined as AXi, and when the two long sides 22Ac, 22Ad are divided into J parts in the length direction, the length of the widthwise outline of the perforated area at any position Aj (where 1≦j≦J+1) is defined as AYj.

[0080] In the following description, the sides in the width direction D1 are referred to as short sides 22Aa and 22Ab, and the sides in the longitudinal direction D2 are referred to as long sides 22Ac and 22Ad, but this is not limited to this, and the sides in the width direction D1 may be long sides and the sides in the longitudinal direction D2 may be short sides.

[0081] In this case, the metal mask 20 of the present disclosure is configured so that AXi and AYj satisfy the following formulas (3) and (4). By defining the outer shape 22T of each perforated region 22 in this manner, it is possible to improve the positional accuracy of the through holes when the metal mask 20 is placed on the frame 15. AXi≦AXi+1 (3) AYmax-AYmin≦12.5 μm (4) AYmax: maximum value of AYj (1≦j≦J+1) AYmin: minimum value of AYj (1≦j≦J+1)

[0082] In this disclosure, when the short sides 22Aa, 22Ab are divided into I parts in the width direction D1, i refers to any division points arranged in the order of 1, 2, ..., i-1, i, i+1, ..., I from one end to the other in the width direction D1. Also, AX1, AX2, ..., AXi-1, AXi, AXi+1, ..., AXI refer to the distances when connecting the division points with the same number (1, 2, ..., i-1, i, i+1, ..., I) on the short sides 22Aa, 22Ab of the perforated region A.

[0083] Similarly, j represents any division points arranged in the order of 1, 2, ..., j-1, j, j+1, ..., J from one end to the other end in the longitudinal direction D2 when the two long sides 22Ac, 22Ad are divided into J parts in the longitudinal direction D2. Also, AY1, AY2, ..., AYj-1, AYj, AYj+1, ..., AYJ represent the distances when connecting the division points with the same number (1, 2, ..., j-1, j, j+1, ..., J) on the long sides 22Tc, 22Td of the perforated region A.

[0084] Equation (3) means that the length AXi in the longitudinal direction D2 of the outer shape 22A may increase from the long side 22Ac toward the long side 22Ad. In other words, as shown in the following equation (6), the longitudinal length AXi does not take a minimum value. This allows the metal mask 20 to be placed on the frame 15 in a flat state by applying tension so that the longitudinal lengths AX1 and AXI are approximately the same. This improves the positional accuracy of the through holes when the metal mask 20 is placed on the frame 15. AXi-1>AXi<AXi+1 ... (6)

[0085] From this viewpoint, (AXI-AX1) is preferably 15 μm or less, 12.5 μm or less, 10 μm or less, or 7.5 μm or less. The lower limit of (AXI-AX1) is preferably 1 μm or more, 1.5 μm or more, 2 μm or more, or 2.5 μm or more. Furthermore, (AXI-AX1) is preferably 1 to 15 μm, 1.5 to 12.5 μm, 2 to 10 μm, or 2.5 to 7.5 μm. From equation (3), AXI is the maximum value in the longitudinal direction D2 of any perforated region A, and AX1 is the minimum value. Therefore, (AXI-AX1) represents the difference between the maximum and minimum values ​​of the length of the outer shape 22T of the perforated region 22 in the longitudinal direction D2.

[0086] From the same viewpoint, (AXI-AX1) / AYave is preferably 4.0×10 －５ is less than or equal to 3.5 × 10 －５ is less than or equal to 3.0 × 10 －５ is less than or equal to 2.5 × 10 －５ The lower limit of (AXI-AX1) / AYave is preferably 2.5×10 －６ or more, 5.0 × 10 －６ or more, 7.5 × 10 －６ or more, 1.0 × 10 －５ Furthermore, (AXI-AX1) / AYave is preferably 2.5×10 －６ ~4.0 x 10 －５ is 5.0 × 10 －６ ~3.5 x 10－５ is 7.5 × 10 －６ ~3.0 x 10 －５ is 1.0 × 10 －５ ~2.5 x 10 －５ AYave may be expressed as follows. AYave refers to the average of AY1, AY2, ..., AYJ. Therefore, (AXI-AX1) / AYave refers to the value of (AXI-AX1) per unit length of perforated region 22 in width direction D1.

[0087] Furthermore, equation (4) means that there is little variation in the length AYj of the outer shape 22T in the width direction D1. As shown in Figure 5, when multiple metal masks 20 are placed on the frame 15, it may be difficult to apply tension in the width direction D1. In this regard, because there is little variation in AYj, it is possible to improve the positional accuracy of the through holes when the metal masks 20 are placed on the frame 15 without applying tension.

[0088] From this viewpoint, (AYmax - AYmin) is preferably 12.5 μm or less, 12 μm or less, 11 μm or less, 10 μm or less, 9 μm or less, 8 μm or less, or may be 7 μm or less. The lower limit of (AYmax - AYmin) is preferably 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, or may be 5 μm or more. (AYmax - AYmin) is preferably 1 to 12.5 μm, 2 to 12 μm, 3 to 11 μm, 4 to 10 μm, or may be 5 to 9 μm.

[0089] From the same viewpoint, (AYmax-AYmin) / AXI is 9.5×10 －５ is less than or equal to 8.0 × 10 －５ is less than or equal to 6.5 × 10 －５ is less than or equal to 5.0 × 10 －５ The lower limit of (AYmax-AYmin) / AXI is preferably 5.0×10 －６ or more, 5.0 × 10 －５ or more, 2.0 × 10 －５ or more, 3.0 × 10 －５Furthermore, (AYmax-AYmin) / AXI is preferably 5.0×10 －６ ~9.5 x 10 －５ is 5.0 × 10 －５ ~8.0 x 10 －５ is 2.0 × 10 －５ ~6.5 x 10 －５ is 3.0 × 10 －５ ~5.0 x 10 －５ Here, (AYmax-AYmin) / AXI means the value of (AYmax-AYmin) per unit length of the perforated region 22 in the longitudinal direction D2.

[0090] The positional accuracy of the through holes tends to decrease when the outer shape 22A of the perforated region 22 is large, particularly when the screen size is larger than that of a tablet, mobile PC, etc. Therefore, in the present disclosure, it is more preferable that the positional accuracy of the through holes be improved when the metal mask 20 is placed on the frame 15 for an outer shape 22A of a predetermined dimension.

[0091] From this viewpoint, AX1 is preferably 50 mm or more, 75 mm or more, 100 mm or more, or may be 125 mm or more. AX1 is also preferably 300 mm or less, 275 mm or less, 250 mm or less, or 225 mm or less. AX1 may also be preferably 50 to 300 mm, 75 to 275 mm, 100 to 250 mm, or 125 to 225 mm.

[0092] Furthermore, AYmin may be preferably 150 mm or more, 200 mm or more, 225 mm or more, 250 mm or more, 275 mm or more, or 300 mm or more. Furthermore, AYmin may be preferably 450 mm or less, 400 mm or less, 375 mm or less, 350 mm or less, or 325 mm or less. Furthermore, AYmin may be preferably 150 to 450 mm, 200 to 400 mm, 225 to 375 mm, 250 to 350 mm, or 275 to 325 mm.

[0093] Similarly, (AYmin) / AX1 is preferably 0.6 or more, 0.8 or more, 1.0 or more, or may be 1.1 or more. Also, (AYmin) / AX1 is preferably 2.5 or less, 2.2 or less, 2.0 or less, or may be 1.8 or less. Furthermore, (AYmin) / AX1 is preferably 0.6 to 2.5, 0.8 to 2.2, 1.0 to 2.0, or may be 1.1 to 1.8.

[0094] In the present disclosure, the "outer shape 22T" refers to the overall shape of one or more perforated regions. Specifically, if the metal mask 20 has one perforated region 22, the outer shape 22T has the same contour as the shape of the perforated region 22. Furthermore, as shown in FIG. 1A , if the metal mask 20 has multiple perforated regions 22, the outer shape 22T has the same contour as the overall shape of the multiple perforated regions 22. In other words, if a surrounding region 23 is located between each perforated region 22 and the perforated regions 22 are separated by the surrounding region 23, the overall shape of the multiple perforated regions 22 as if they were not separated is referred to as the outer shape 22T.

[0095] Furthermore, the "outer shape 22A" refers to the shape of each perforated region. Specifically, if the metal mask 20 has one perforated region 22, the outer shape 22A is synonymous with the outer shape 22T. Furthermore, if the metal mask 20 has multiple perforated regions 22, an outer shape 22A having the same contour as the shape of each perforated region 22 is defined for each of the perforated regions 22.

[0096] With the above configuration, the difference in the outer shape of the perforated region 22 is reduced, improving the uniformity of quality, even if the metal mask 20 inevitably has distortion resulting from the corrugated shape of the metal plate 51. Furthermore, the metal mask 20 obtained in this manner has excellent positional accuracy of the through holes when placed on the frame 15.

[0097] The method for measuring Xn and Ym is not particularly limited. For example, as shown in FIG. 1B , the outline 22T of the perforated region 22 is identified from image data of the metal mask 20 viewed in plan view, and the short sides 22Ta and 22Tb and the long sides 22Tc and 22Td of the outline 22T are identified. Then, as image processing, division points are identified by dividing each of the short sides 22Ta and 22Tb into N, and similarly, division points are identified by dividing each of the long sides 22Tc and 22Td into M. Finally, Xn and Ym can be measured based on each division point. The same applies to AXi and AYj.

[0098] In the above example, a method for identifying the division points by image processing was described. However, instead of this, marks may be attached to the metal mask 20 at locations corresponding to the division points. The marks indicating the division points may be formed in a concave shape by half-etching at desired positions on the first surface 20a or the second surface 20b in the first-surface etching step or the second-surface etching step described below. Alternatively, through holes extending from the first surface 20a to the second surface 20b may be formed and used as marks indicating the division points. When marks are attached, Xn and Ym can be measured by measuring the distance between the two corresponding marks. The same applies to AXi and AYj.

[0099] Note that "N division" refers to dividing into N equal parts. As shown in FIG. 1B , when the short sides 22Ta and 22Tb are divided into N parts in the width direction D1, positions 1 and N+1 correspond to the two end points of the short sides 22Ta and 22Tb. N-1 equal division points, from positions 2 to N, are located between the two end points of the short sides 22Ta and 22Tb. The number of divisions N is not particularly limited as long as it is a natural number, but may be 5 to 30, 7 to 25, or 10 to 20. The distance between any two positions n and n+1 is also not particularly limited, but may be 0.5 to 3.5 mm, 1.0 to 3.0 mm, or 1.5 to 2.5 mm. Note that n is also a natural number.

[0100] Similarly, "M division" refers to dividing into M equal parts. As shown in FIG. 1B, when the long sides 22Tc and 22Td are divided into M parts in the longitudinal direction D2, positions 1 and M+1 correspond to the two end points of the long sides 22Tc and 22Td. Between the two end points of the long sides 22Tc and 22Td are located M-1 equal division points, from positions 2 to M. The number of divisions M is not particularly limited as long as it is a natural number, but may be 25 to 65, 30 to 60, 35 to 55, or 40 to 50. The distance between any positions m and m+1 is also not particularly limited, but may be 0.5 to 3.5 mm, 1.0 to 3.0 mm, or 1.5 to 2.5 mm. Note that m is also a natural number.

[0101] "I division" refers to dividing into I equal parts. As shown in FIG. 1C , when the short sides 22Aa and 22Ab are divided into I parts in the width direction D1, positions 1 and I+1 correspond to the two end points of the short sides 22Aa and 22Ab. Between the two end points of the short sides 22Aa and 22Ab, I-1 equal division points are located, from positions 2 to I. The number of divisions I is not particularly limited as long as it is a natural number, but may be 5 to 30, 7 to 25, or 10 to 20. The distance between any positions i and i+1 is also not particularly limited, but may be 0.5 to 3.5 mm, 1.0 to 3.0 mm, or 1.5 to 2.5 mm. Note that i is also a natural number.

[0102] "J division" refers to dividing into J equal parts. As shown in FIG. 1C , when the long sides 22Ac and 22Ad are divided into J parts in the longitudinal direction D2, positions 1 and J+1 correspond to the two end points of the long sides 22Ac and 22Ad. Between the two end points of the long sides 22Ac and 22Ad, J-1 equal division points are located, from position 2 to position J. The number of divisions J is not particularly limited as long as it is a natural number, but may be 5 to 30, 7 to 25, or 10 to 20. The distance between any given position j and position j+1 is also not particularly limited, but may be 0.5 to 3.5 mm, 1.0 to 3.0 mm, or 1.5 to 2.5 mm. Note that j is also a natural number.

[0103] Finally, a method for manufacturing a metal mask according to an embodiment of the present disclosure will be described.

[0104] A method for manufacturing a metal mask according to one embodiment of the present disclosure includes a preparation step of preparing a metal plate 51 having a first surface 51a and a second surface 51b located opposite the first surface 51a, and an etching step of forming the metal mask 20 by etching the metal plate 51.

[0105] First, the preparation step of preparing the metal plate 51 will be described.

[0106] The preparation process includes a rolling process in which a base material is rolled to obtain the metal plate 51, and may also include a slitting process in which both ends of the metal plate 51 are cut, and an annealing process in which the metal plate 51 is heat-treated, as necessary.

[0107] The rolling step is a step of rolling the base material to obtain the metal plate 51. The rolling method is not particularly limited, but an example is a method of rolling the base material using a pair of rolling rolls that roll the base material in the thickness direction. During this process, the thickness of the base material is reduced and the base material is stretched along the conveying direction. This results in the metal plate 51. The metal plate 51 may be wound around a core 52 to form a wound body 50.

[0108] 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 recrystallization temperature of the Invar material constituting the base material, or a cold rolling process in which the base material is processed at a temperature equal to or lower than the recrystallization temperature of the Invar material. The conveying direction of the base material during rolling is not limited to this. The base material may be conveyed back and forth between rolling rolls and rolled during the process.

[0109] Furthermore, in the rolling step, the steel sheet may be rolled to the desired thickness in one go, or may be rolled to the desired thickness by performing the rolling step multiple times at a predetermined rolling ratio. Furthermore, during rolling, rolling oil or the like may be used as needed.

[0110] From the viewpoint of adjusting the wave shape of the metal plate 51 of the present disclosure and thereby adjusting the outer shape 22T and the outer shape 22A to satisfy the above-mentioned specified conditions, the pressing conditions of the rolling process may be adjusted to include the uniformity of the pressing force fluctuation and the uniformity of the pressing force distribution.

[0111] From the viewpoint of obtaining a metal plate 51 in which the waviness is suppressed, it is preferable that the pressing force does not fluctuate and is constant. However, the base material has a hard metal structure in some parts, or is thick in other parts. Therefore, the pressing force applied to the rolls that roll the base material fluctuates as the base material passes through. Methods for suppressing such fluctuations in pressing force include increasing the number of rolls or providing an adjustment mechanism to keep the pressing force constant. By doing so, uniformity in the fluctuations in pressing force is maintained, which tends to suppress the waviness.

[0112] Furthermore, from the viewpoint of obtaining a metal plate 51 in which the waviness is suppressed, it is preferable that the pressing force applied by the roll to the base material be uniform in the width direction and that the pressing force not vary depending on the location where the roll and the base material contact. However, the base material may have a hard metal structure in some parts or may be thick in other parts. Therefore, the pressing force applied by the roll that rolls the base material may be uneven in the width direction. To suppress such uneven pressing force, an adjustment mechanism for maintaining a constant pressing force at both ends of the roll may be provided. This maintains a uniform pressing force distribution, which tends to suppress waviness.

[0113] The slitting process is a process of cutting both ends of the metal plate 51. If one end of the metal plate 51 has a region with a relatively large wave shape, the one end of the metal plate 51 may be cut. This allows the portion of the metal plate 51 with the small wave shape to be used in manufacturing the metal mask 20. This method also allows the outer shape 22T and the outer shape 22A to be adjusted to satisfy the above-mentioned predetermined conditions.

[0114] The annealing step is a step of heat-treating the metal sheet 51. This removes residual stress (internal stress) accumulated in the metal sheet 51 due to rolling. The heat-treatment method is not particularly limited, but for example, the metal sheet 51 may be heat-treated using an annealing device while being transported by roll-to-roll. Furthermore, the heat treatment may be performed while the metal sheet 51 is pulled in the transport direction (longitudinal direction D2). Alternatively, the heat treatment may be performed in a batch manner with the metal sheet 51 wound around the core 52.

[0115] The annealing step may be performed in a non-reducing atmosphere or an inert gas atmosphere. Here, a non-reducing atmosphere refers to an atmosphere that is substantially free of reducing gases such as hydrogen. "Substantially free of reducing gases" means that the concentration of reducing gases such as hydrogen is 4% or less. An inert gas atmosphere refers to an atmosphere in which an inert gas such as argon gas, helium gas, or nitrogen gas is present at 90% or more.

[0116] The processing conditions for the annealing step can be set appropriately depending on the thickness, rolling ratio, etc. of the metal plate 51. For example, the processing conditions for the annealing step may be 500° C. and 60 seconds.

[0117] The rolling process, the slitting process, and the annealing process may be repeated multiple times. In this case, these processes may be performed in any order. The metal sheet manufacturing method of the present disclosure tends to produce a metal sheet 51 with high uniformity over a wider range. The long metal sheet 51 constructed as described above may be cut to produce a short metal sheet 51.

[0118] Next, a method for manufacturing the metal mask 20 from the metal plate 51 by etching will be described. The metal mask 20 may be formed by etching, laser processing, or electroforming.

[0119] A method for manufacturing a metal mask 20 according to an embodiment of the present disclosure will be described primarily with reference to FIGS. 4A to 4E . FIG. 4A is a schematic diagram illustrating a manufacturing apparatus 70 for manufacturing a metal mask 20 using a metal plate 51, along with the processing sequence. FIG. 4A illustrates an example in which the metal plate 51 is continuously supplied from a resist film forming apparatus 71 to a separating apparatus 75. However, the method for manufacturing a metal mask 20 according to the present disclosure is not limited to this. For example, the metal plate 51 may be wound into a wound body after each process performed by each apparatus. Furthermore, when supplying the metal plate 51 to each apparatus, the metal plate 51 may be unwound from the wound body 50.

[0120] Each step of the method for manufacturing the metal mask 20 will be described in detail below.

[0121] First, a metal plate 51 having a desired thickness is prepared (preparation step). The metal plate 51 may be in the form of a wound body 50 wound around a core 52. The method for producing the metal plate 51 having the desired thickness is not particularly limited, but examples thereof include a rolling method and a plating film formation method.

[0122] Next, a first resist film 53a and a second resist film 53b are formed on the first surface 51a and the second surface 51b of the metal plate 51 using a resist film forming apparatus 71 (FIG. 4B). Specifically, the first resist film 53a and the second resist film 53b may be formed by attaching a dry film resist to the first surface 51a and the second surface 51b. Alternatively, the first resist film 53a and the second resist film 53b may be formed by applying a coating liquid containing a photosensitive resist material to the first surface 51a and the second surface 51b and drying the coating liquid.

[0123] The dry film resist and coating liquid are not particularly limited, and conventionally known ones can be used. The resist films 53a and 53b thus formed may be either negative resist or positive resist. Of these, negative resists are preferably used.

[0124] The thickness of the first resist film 53a and the second resist film 53b is preferably 15 μm or less, 10 μm or less, 6 μm or less, or may be 4 μm or less. The thickness of the first resist film 53a and the second resist film 53b is preferably 1 μm or more, 3 μm or more, 5 μm or more, or 7 μm or more. The thickness range of the first resist film 53a and the second resist film 53b may be determined by a combination of any one of the above-mentioned multiple upper limit candidate values ​​and any one of the above-mentioned multiple lower limit candidate values.

[0125] Next, the first resist film 53 a and the second resist film 53 b are exposed and developed using the exposure / development device 72. As a result, a first resist pattern 53 c is formed on the first surface 51 a, and a second resist pattern 53 d is formed on the second surface 51 b, as shown in FIG. 4C . For example, when a negative resist film is used, a photomask that blocks light from passing through the region of the resist film that is to be removed may be placed on the resist film, the resist film may be exposed through the photomask, and the resist film may then be developed.

[0126] Subsequently, the metal plate 51 is etched using the etching device 73 with the first resist pattern 53c and the second resist pattern 53d as a mask (etching step). The etching step may include a first-side etching step and a second-side etching step.

[0127] 4D is a schematic diagram illustrating an example of the first-surface etching step for the perforated region 22. In the first-surface etching step, the region of the first surface 51a that is not covered by the first resist pattern 53c is etched using an etching solution. At this time, the second surface 51b may be covered with a resin or the like that is resistant to the etching solution.

[0128] The etching solution erodes the first surface 51a that is not covered by the first resist pattern 53c (FIG. 4D). As a result, numerous first recesses 30 are formed on the first surface 51a. Note that etching of the metal plate 51 can proceed isotropically in various directions from the holes in the resist pattern. Therefore, the cross-sectional areas of the first recesses 30 and second recesses 35 at each position along the thickness direction of the metal mask 20 gradually decrease as they progress from the surface in the thickness direction.

[0129] 4E is a schematic diagram illustrating an example of the second-side etching step for the perforated region 22. In the second-side etching step, the region of the second surface 51b that is not covered by the second resist pattern 53d is etched using an etching solution. At this time, a film or the like that covered the second surface 51b in the first-side etching step may be peeled off beforehand. In addition, the first surface 51a may be covered with a resin 54 or the like that is resistant to the etching solution.

[0130] The etching solution erodes the second surface 51b that is not covered by the second resist pattern 53d (FIG. 4E). As a result, a second recess 35 is formed on the second surface 51b. The first recess 30 and the second recess 35 then communicate with each other, thereby forming a through hole 25.

[0131] The etching solution is not particularly limited as long as it is a conventionally known solution, and examples thereof include those containing ferric chloride solution and hydrochloric acid.

[0132] In the second surface etching step, as shown in FIG. 4E , etching may be performed until adjacent second recesses 35 are connected. At the locations where adjacent second recesses 35 are connected, the adjacent second recesses 35 merge to form ridge lines 33. Furthermore, the ridge lines 33 are separated from the second resist pattern 53d, and etching erosion at the tops of the ridge lines 33 also progresses in the thickness direction of the metal plate 51. This causes the second resist pattern 53d to peel off from the metal plate 51. Note that portions of the second surface 51b may remain between adjacent second recesses 35. In this case, the ridge lines 33 connect the remaining second surfaces 51b. Furthermore, etching does not have to be performed until adjacent second recesses 35 are connected.

[0133] Furthermore, a peeling device 74 is used to peel off the resist pattern, the resin 54 that is resistant to the etching solution, and the like from the metal plate 51. Then, a separation device 75 is used to cut the long metal plate 51, thereby performing a separation step in which the metal mask 20 made of a sheet of metal plate is separated from the metal plate 51. In this manner, the metal mask 20 is obtained.

[0134] A metal mask apparatus 10 according to an embodiment of the present disclosure includes a frame 15 and the above-described metal mask 20 placed on the frame 15. The metal mask 20 may be placed on the frame 15 with the second surface 20b in contact with the frame 15. Fig. 5 shows a plan view of the metal mask apparatus 10 as viewed from the first surface 20a side of the metal mask 20. Fig. 6 shows a cross-sectional view of the vapor deposition apparatus.

[0135] In the metal mask device 10 of the present disclosure, multiple metal masks 20 may be attached to one frame ( FIG. 5 ). In this case, the multiple metal masks 20 may be aligned in a width direction D1 that intersects with the longitudinal direction D2 of the metal masks 20. Furthermore, each metal mask 20 may be fixed to the frame 15 at both ends 23 a of the metal mask 20 in the longitudinal direction D2.

[0136] The method of fixing to the frame 15 is not particularly limited, but may be, for example, welding.

[0137] The metal mask device 10 may include a member that is fixed to the frame 15 and that partially overlaps the metal mask 20 in the thickness direction of the metal mask 20. Examples of such a member are not particularly limited, but include, for example, a member that extends in a direction intersecting the longitudinal direction of the metal mask 20 and supports the metal mask 20, and a member that overlaps the gap between two adjacent metal masks.

[0138] Next, a method for manufacturing an organic EL display device using the metal mask 20 according to the present disclosure will be described with reference to Fig. 6. The organic EL display device may include a substrate 92 and a deposition layer including a deposition material 98 provided in a pattern, stacked together.

[0139] The method for manufacturing an organic EL display device according to an embodiment of the present disclosure is not particularly limited, but includes, for example, a vapor deposition step of depositing a vapor deposition material 98 on a substrate such as the substrate 92 using a metal mask 20 .

[0140] In the vapor deposition process, first, the metal mask device 10 is positioned so that the metal mask 20 faces the substrate 92. At this time, as shown in Fig. 6, the first surface 20a of the metal mask 20 may face the substrate 92. Here, the substrate 92 is a vapor deposition target such as a glass substrate.

[0141] 6, when the metal mask device 10 is housed in the vapor deposition device 90, the surface of the metal mask 20 facing the substrate 92 is the first surface 20a, and the surface of the metal mask 20 facing the crucible 94 holding the vapor deposition material 98 is the second surface 20b. In the vapor deposition device 90, the metal mask 20 is placed on the surface of the substrate 92 facing the crucible 94. Here, the metal mask 20 and the substrate 92 may be brought into close contact with each other by magnetic force.

[0142] A crucible 94 containing a deposition material 98 and a heater 96 for heating the crucible 94 may be disposed below the metal mask device 10 within the deposition device 90. Here, the deposition material 98 may be, for example, an organic light-emitting material. The deposition material 98 in the crucible 94 is vaporized or sublimated by the heat from the heater 96. The vaporized or sublimated deposition material 98 adheres to the substrate 92 through the through-holes 25 of the metal mask 20. As a result, the deposition material 98 is formed into a film on the surface of the substrate 92 in a desired pattern corresponding to the positions of the through-holes 25 of the metal mask 20. Note that the interior of the deposition device 90 may be in a vacuum atmosphere during the deposition process.

[0143] When it is desired to deposit different types of evaporation materials according to pixels such as RGB, the evaporation materials 98 may be formed on the surface of the substrate 92 using different metal masks 20 according to the colors of the evaporation materials 98. For example, the evaporation material 98 for red, the evaporation material 98 for green, and the evaporation material 98 for blue may be deposited in this order on the substrate 92. Alternatively, the evaporation material 98 for red, the evaporation material 98 for green, and the evaporation material 98 for blue may be deposited in this order by gradually moving the metal mask 20 (metal mask device 10) and the substrate 92 relative to each other along the arrangement direction of the through holes 25 (the aforementioned one direction).

[0144] The method for manufacturing an organic EL display device may include various processes other than the vapor deposition process of depositing a vapor deposition material 98 on a substrate such as the substrate 92 using the metal mask 20. For example, the method for manufacturing an organic EL display device may include a process of forming a first electrode on the substrate. A vapor deposition layer is formed on the first electrode. The method for manufacturing an organic EL display device may also include a process of forming a second electrode on the vapor deposition layer. The method for manufacturing an organic EL display device may also include a sealing process of sealing the first electrode, the vapor deposition layer, and the second electrode provided on the substrate 92.

[0145] The vapor deposition layer formed on a substrate such as the substrate 92 using the metal mask 20 is not limited to the light-emitting layer formed by vapor deposition of the organic light-emitting material described above, and may include other layers. For example, the vapor deposition layer may include, in order from the first electrode side, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, etc. In this case, a vapor deposition process using a metal mask 20 corresponding to each layer may be performed.

[0146] The present disclosure will be described in more detail below using examples and comparative examples, but the present disclosure is not limited to the following examples.

[0147] Example: Using the above-described method for manufacturing a metal mask, a metal mask was manufactured having a through hole consisting of a first recess and a second recess in a metal plate. The metal mask was shaped like a stick with four perforated regions arranged in the longitudinal direction D2, as shown in Figure 1A. During the manufacturing of the metal mask, half-etching marks were provided around the perforated regions, with the short sides divided into N parts in the width direction and the long sides divided into M parts in the longitudinal direction.

[0148] The metal plate used in the examples was made of Invar material. The pressure in the rolling process was adjusted so that the pressing force did not fluctuate as the base material passed through, and the metal plate used in the examples was cut in the slitting process to reduce the waviness compared to the comparative example.

[0149] Comparative Example A metal mask was obtained in the same manner as in the example, except that the pressure was not adjusted so that the pressing force would not fluctuate relatively as the base material passed.

[0150] (Positional Accuracy) A deposition mask device was fabricated by placing a metal mask on a frame as shown in FIG. 5 while applying tension as shown in FIG. 3E . Then, the first surface of the metal mask of the deposition mask device was brought into close contact with a deposition substrate made of alkali-free glass. Then, a deposition material made of an organic light-emitting material was deposited on the deposition substrate through the through-holes formed in each metal mask. After removing the deposition mask from the deposition substrate, the positional accuracy of the deposition material when the metal mask was stretched was evaluated.

[0151] The positional accuracy of the deposition material when the metal mask was stretched was evaluated using a two-dimensional coordinate size measuring instrument according to the following evaluation criteria: A: Positional deviation less than 5.0 μm B: Positional deviation of 5.0 μm or more and less than 10 μm C: Positional deviation of 10 μm or more and less than 15 μm D: Positional deviation of 15 μm or more

[0152]

[0153] The metal mask of the present disclosure has industrial applicability, for example, as a metal mask used in the manufacture of organic EL display devices.

[0154] 10...metal mask device, 15...frame, 20...metal mask, 20a...first surface, 20b...second surface, 22...perforated area, 22A...outer shape, 22Aa, 22Ab...short sides, 22Ac, 22Ad...long sides, 22T...outer shape, 22Ta, 22Tb...short sides, 22Tc, 22Td...long sides, 23...peripheral area, 23a...edge, 25...through hole, 27...outer shape, 30...first recess, 31...first wall surface, 33...ridge line, 35...second recess, 36...second wall surface, 41...connection portion, 50 ...wound body, 51...metal plate, 51a...first surface, 51b...second surface, 52...core, 53a...first resist film, 53b...second resist film, 53c...first resist pattern, 53d...second resist pattern, 54...resin, 70...manufacturing equipment, 71...resist film forming equipment, 72...exposure / developing equipment, 73...etching equipment, 74...peeling equipment, 75...separating equipment, 86...clamp, 90...evaporation equipment, 92...substrate, 94...crucible, 96...heater, 98...evaporation material.​

Claims

1. A metal mask having one or more perforated regions and a surrounding region, wherein the overall outline of the one or more perforated regions has two short sides in the width direction and two long sides in the longitudinal direction, wherein when the two short sides are divided into N in the width direction, the length of the outline of the perforated region in the longitudinal direction at any position n (where 1≦n≦N+1) is taken as Xn, and when the two long sides are divided into M in the longitudinal direction, the length of the outline of the perforated region in the width direction at any position m (where 1≦m≦M+1) is taken as Ym, wherein Xn and Ym satisfy the following formulas (1) and (2): Xn≦Xn+1 (1) Ymax - Ymin ≦12.5μm (2) Ymax: maximum value of Ym (1≦m≦M+1) Ymin: minimum value of Ym (1≦m≦M+1).

2. The metal mask according to claim 1, wherein X1 is 700 mm or more.

3. The metal mask according to claim 1, wherein Ymin is 200 mm or more.

4. The metal mask according to claim 1, wherein (Ymin / X1) is 0.3 or more.

5. The device has a plurality of perforated regions, each of the plurality of perforated regions having an outer shape with two short sides in the width direction and two long sides in the length direction, and in any one of the perforated regions A, when the two short sides are divided into I parts in the width direction, the length of the outer shape of the perforated region in the length direction at any position Ai (where 1≦i≦I+1) is taken as AXi, and when the two long sides are divided into J parts in the length direction, the length of the outer shape of the perforated region in the width direction at any position Aj (where 1≦j≦J+1) is taken as AYj, where AXi and AYj satisfy the following formulas (3) and (4): AXi≦AXi+1 ... (3) AYmax - AYmin ≦ 12.5 μm ... (4) AYmax: maximum value of AYj (1≦j≦J+1) AYmin: The minimum value of AYj (1≦j≦J+1). The metal mask according to claim 1 .

6. A method for manufacturing a metal mask, comprising: a step of preparing a metal plate; and an etching step of etching the metal plate to form a metal mask, the method comprising: one or more perforated regions and a peripheral region; the overall outline of the one or more perforated regions has two short sides in the width direction and two long sides in the length direction; when the two short sides are divided into N in the width direction, the length of the outline of the perforated region in the length direction at any position n (where 1≦n≦N+1) is taken as Xn; when the two long sides are divided into M in the length direction, the length of the outline of the perforated region in the width direction at any position m (where 1≦m≦M+1) is taken as Ym; Xn and Ym satisfy the following formulas (1) and (2): Xn≦Xn+1 ... (1) Ymax - Ymin ≦ 12.5 μm ... (2) Ymax: maximum value of Ym (1≦m≦M+1) Ymin: Minimum value of Ym (1≦m≦M+1) A method for manufacturing a metal mask.

Images