Vapor deposition mask, method for manufacturing vapor deposition mask, and method for manufacturing display device

Abstract

The metal vapor deposition mask has a surface configured to face the vapor deposition source and a plurality of mask holes each including a hole portion having an inverted frustum shape. The hole portion of each mask hole has a small opening and a large opening. When viewed from a viewpoint facing the surface of the vapor deposition mask, the small opening has a polygonal edge including a plurality of corners and a plurality of linear portions respectively located between adjacent corners. When viewed from a viewpoint facing the surface, the large opening has an edge of a shape formed by the corners of the edge of the small opening extending outward relative to the edge of the small opening. The large opening is located on the surface. When viewed from a viewpoint facing the surface, the large opening surrounds the small opening.

Description

Technical Field

[0001] The present invention relates to a vapor deposition mask, a method for manufacturing the vapor deposition mask, and a method for manufacturing a display device. Background Art

[0002] The display element of the organic EL display is formed by a vapor deposition method using a vapor deposition mask. The vapor deposition mask has a surface, a back surface, and a plurality of mask holes that penetrate the surface and the back surface. Each mask hole is open on the surface and the back surface. The large opening of the mask hole is located on the surface, and the small opening of the mask hole is located on the back surface. When the vapor deposition mask is used for vapor deposition on the vapor deposition object, the surface of the vapor deposition mask is opposite to the vapor deposition source, and the back surface of the vapor deposition mask is opposite to the vapor deposition object (for example, refer to patent document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-55007 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] In addition, the mask hole of the vapor deposition mask has an inverted frustum shape in a cross section along a plane perpendicular to the surface of the vapor deposition mask. The small opening of the mask hole has a shape corresponding to the shape required by the display element. In order to form a polygonal display element having a quadrilateral shape or the like, the small opening of the mask hole usually has a shape including a corner in a plan view opposite to the surface of the vapor deposition mask.

[0008] On the other hand, in the evaporation material flying from the evaporation source to the evaporation mask, the angle formed by the evaporation material's flying direction and the surface of the evaporation mask is the evaporation material's flight angle. The evaporation material flying toward the evaporation mask includes evaporation materials with various flight angles. Most of the evaporation material that enters the mask hole from the vicinity of the center of the large opening reaches the small opening from the large opening regardless of the evaporation material's flight angle.

[0009] In this regard, part of the evaporation material that enters the mask hole from the edge of the large opening does not reach the small opening but accumulates on the side that divides the mask hole. In particular, even within the edge of the large opening, the evaporation material that enters the mask hole from the corner is mostly blocked from reaching the small opening by the side that divides the mask hole. Therefore, in the evaporation pattern formed by the evaporation material passing through the small opening, the film thickness of the evaporation pattern is biased, and as a result, uneven brightness occurs in the display element having the evaporation pattern.

[0010] In addition, such a technical problem is also common to the case where the mask hole has a shape other than an inverted frustum. For example, the mask hole includes a large hole portion having an inverted frustum shape from the front surface to the back surface and a small hole portion having a frustum shape from the back surface to the front surface, and the opening formed by connecting the large hole portion and the small hole portion functions as the above-mentioned small opening.

[0011] An object of the present invention is to provide a vapor deposition mask capable of suppressing variation in film thickness of a vapor deposition pattern, a method for manufacturing the vapor deposition mask, and a method for manufacturing a display device.

[0012] Means for solving technical problems

[0013] The vapor deposition mask for solving the above-mentioned technical problem is a metal vapor deposition mask. It has a surface formed opposite to the vapor deposition source and a plurality of mask holes each including a hole portion having an inverted frustum shape. The hole portion of each mask hole has: a small opening, which, when observed from a viewpoint opposite to the above-mentioned surface of the vapor deposition mask, has a polygonal edge including a plurality of corners and linear portions respectively located between the adjacent corners; and a large opening, which, when observed from a viewpoint opposite to the above-mentioned surface, has an edge of a shape formed by the corners in the above-mentioned edge of the above-mentioned small opening extending outward relative to the above-mentioned edge of the above-mentioned small opening, and the large opening is located on the above-mentioned surface. When observed from a viewpoint opposite to the above-mentioned surface, the large opening surrounds the above-mentioned small opening.

[0014] A method for manufacturing a vapor deposition mask for solving the above technical problems comprises the following steps: forming a resist mask on at least one of the surface and the back of a metal sheet; and forming a plurality of mask holes in the metal sheet using the resist mask. The step of forming the plurality of mask holes is to form the plurality of mask holes each including a hole portion having an inverted frustum shape on the metal sheet in the following manner: the hole portion of each mask hole has a small opening and a large opening, and when observed from a viewpoint opposite to the surface, the large opening surrounds the small opening, and the small opening has a polygonal edge when observed from a viewpoint opposite to a plane extending from the metal sheet, and the polygonal edge includes a plurality of corners and a plurality of linear portions respectively located between the adjacent corners, and the large opening is located on the surface, and when observed from a viewpoint opposite to the surface, the large opening has an edge of a shape formed by the corners in the edge of the small opening extending outward relative to the edge of the small opening.

[0015] A method for manufacturing a display device for solving the above-mentioned problem includes the steps of: preparing a vapor deposition mask manufactured by the above-mentioned method for manufacturing a vapor deposition mask; and forming a pattern by vapor deposition using the above-mentioned vapor deposition mask.

[0016] According to the above-mentioned vapor deposition mask, vapor deposition mask manufacturing method and display device manufacturing method, since the edge of the large opening located on the surface opposite to the vapor deposition source has a shape in which the corner of the polygon is extended toward the outside of the polygon, the vapor deposition material entering the mask hole from the vicinity of the corner of the large opening becomes easy to reach the small opening. Therefore, the deviation in the film thickness of the vapor deposition pattern can be suppressed.

[0017] In the above-mentioned vapor deposition mask, in a cross section perpendicular to the above-mentioned surface and along the diagonal direction of the above-mentioned small opening, a virtual straight line connecting the above-mentioned corner of the above-mentioned small opening with the corresponding above-mentioned corner of the above-mentioned large opening is a first virtual straight line, and an angle formed by the above-mentioned surface and the above-mentioned first virtual straight line is a first angle. In a cross section perpendicular to the above-mentioned surface and along a direction perpendicular to one of the above-mentioned linear portions of the above-mentioned small opening, a virtual straight line connecting the above-mentioned edge of the above-mentioned small opening with the above-mentioned edge of the above-mentioned large opening is a second virtual straight line, and an angle formed by the above-mentioned surface and the above-mentioned second virtual straight line is a second angle, and the above-mentioned second angle is larger than the above-mentioned first angle. When observed from a viewpoint opposite to the above-mentioned surface, the distance between the above-mentioned corner of the above-mentioned small opening and the above-mentioned corner of the above-mentioned large opening is greater than 1 times and less than 1.5 times the distance between the above-mentioned surface and the plane including the above-mentioned edge of the above-mentioned small opening, and the radius of curvature of the above-mentioned corner of the above-mentioned small opening can be less than 4.5μm.

[0018] In the above-mentioned method for manufacturing the vapor deposition mask, it may be that, in a cross section perpendicular to the above-mentioned surface and along a diagonal direction of the above-mentioned small opening, a virtual straight line connecting the above-mentioned corner of the above-mentioned small opening with the above-mentioned corresponding corner of the above-mentioned large opening is a first virtual straight line, an angle formed by the above-mentioned surface and the above-mentioned first virtual straight line is a first angle, and in a cross section perpendicular to the above-mentioned surface and along a direction perpendicular to one of the above-mentioned linear portions of the above-mentioned small opening, a virtual straight line connecting the above-mentioned edge of the above-mentioned small opening with the above-mentioned edge of the above-mentioned large opening is a second virtual straight line, The angle formed by the surface and the second virtual straight line is the second angle, and the step of forming the plurality of mask holes is a step of forming the plurality of mask holes on the metal sheet in the following manner: the second angle is larger than the first angle, and when observed from a viewpoint opposite to the surface, the distance between the corner of the small opening and the corner of the large opening is more than 1 times and less than 1.5 times the distance between the surface and the plane including the edge of the small opening, and the radius of curvature of the corner of the small opening is less than 4.5 μm. According to the above-mentioned evaporation mask and the manufacturing method of the evaporation mask, the distance between the corner of the edge of the small opening and the corner of the edge of the large opening can be expanded, and the inclination angle of the portion connecting the corner of the edge of the small opening and the corner of the edge of the large opening can be reduced on the side of the mask hole dividing the mask hole, so that the evaporation material can easily pass through the corner of the edge of the small opening. In addition, the corner of the edge of the small opening has a curvature, so that the evaporation material can more easily pass through the corner of the edge of the small opening. As a result, the film thickness at the corners of the vapor deposition pattern is suppressed from becoming smaller than the film thickness at the center, and thus the variation in the film thickness of the vapor deposition pattern can be suppressed.

[0019] In the above-mentioned vapor deposition mask, the above-mentioned vapor deposition mask further includes a back surface which is a surface opposite to the above-mentioned surface, and the above-mentioned plurality of small openings may be located on the above-mentioned back surface. According to the vapor deposition mask, when the vapor deposition pattern is formed on the vapor deposition object, the distance between the small openings and the vapor deposition object can be reduced, compared with the case where the small openings having a shape corresponding to the vapor deposition pattern formed on the vapor deposition object are located between the front surface and the back surface. Therefore, compared with the case where the small openings are located between the front surface and the back surface, the deviation of the film thickness in the vapor deposition pattern formed on the vapor deposition object can be suppressed.

[0020] In the above-mentioned vapor deposition mask, the above-mentioned vapor deposition mask may also have a thickness of 1 μm or more and 20 μm or less. According to this vapor deposition mask, compared with the case where the thickness of the vapor deposition mask exceeds 20 μm, the size of the large opening that can penetrate the metal sheet used to form the vapor deposition mask can be reduced. Therefore, compared with the case where the thickness of the vapor deposition mask exceeds 20 μm, the vapor deposition mask can have a plurality of mask holes at a higher density.

[0021] In the above-mentioned evaporation mask, the material forming the above-mentioned evaporation mask may be an iron-nickel alloy or an iron-nickel-cobalt alloy. According to the evaporation mask, when the glass substrate is evaporated using the evaporation mask, the difference between the expansion degree of the evaporation mask and the expansion degree of the glass substrate is suppressed from becoming excessively large due to the heating of the evaporation mask and the glass substrate. Therefore, the precision of the evaporation pattern formed on the glass substrate using the evaporation mask is suppressed from being reduced due to the difference between the expansion rate of the evaporation mask and the expansion rate of the glass substrate.

[0022] Effects of the Invention

[0023] According to the present invention, it is possible to suppress variations in film thickness of a vapor deposition pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a perspective view showing the structure of a vapor deposition mask in one embodiment.

[0025] Figure 2 It is a plan view showing the shape of the mask hole viewed from a viewpoint facing the surface of the vapor deposition mask.

[0026] Figure 3 It is along Figure 2 Cross-sectional view along line III-III.

[0027] Figure 4 It is along Figure 2 Cross-sectional view along line IV-IV.

[0028] Figure 5 It is a plan view showing a part of a small opening provided in the mask hole in an enlarged manner.

[0029] Figure 6 The following are process diagrams for explaining a method for manufacturing a vapor deposition mask in one embodiment.

[0030] Figure 7 This is a process diagram for explaining a method for manufacturing a vapor deposition mask.

[0031] Figure 8 It is a plan view showing the shape of the mask hole provided in the resist mask when viewed from above facing the surface of the metal sheet.

[0032] Fig. 9 This is a process diagram for explaining a method for manufacturing a vapor deposition mask.

[0033] Fig.10 It is a plan view showing the structure of a mask device to which a vapor deposition mask is applied.

[0034] Fig.11 It is a plan view showing a part of a first modified example of the shape of the mask hole viewed from a viewpoint facing the surface of the vapor deposition mask.

[0035] Fig.12 It is a plan view showing a part of a second modified example of the shape of the mask hole viewed from a viewpoint facing the surface of the vapor deposition mask.

[0036] Fig.13 It is a plan view showing a part of a third modified example of the shape of the mask hole viewed from a viewpoint facing the surface of the vapor deposition mask.

[0037] Fig.14 It is a plan view showing a part of a fourth modified example of the shape of the mask hole viewed from a viewpoint facing the surface of the vapor deposition mask.

[0038] Fig.15 It is a plan view showing a part of a fifth modification example of the shape of the mask hole viewed from a viewpoint facing the surface of the vapor deposition mask.

[0039] Fig.16 It is a plan view showing a part of a sixth modified example of the shape of the mask hole viewed from a viewpoint facing the surface of the vapor deposition mask.

[0040] Fig.17 It is a top view showing a seventh modification example of the shape of the mask hole as viewed from a viewpoint facing the surface of the vapor deposition mask.

[0041] Fig.18 It is a cross-sectional view showing an eighth modification example of the shape of the mask hole of the vapor deposition mask. DETAILED DESCRIPTION

[0042] Reference Figures 1 to 10 , an embodiment of a vapor deposition mask, a method for manufacturing a vapor deposition mask, and a method for manufacturing a display device is described. Hereinafter, a vapor deposition mask, a method for manufacturing a vapor deposition mask, a mask device, and an embodiment are described in sequence.

[0043] [Evaporation mask]

[0044] Reference Figures 1 to 5 , illustrating the evaporation mask.

[0045] Figure 1 A pattern region and a part of a peripheral region included in the vapor deposition mask are shown.

[0046] Figure 1 The vapor deposition mask 10 shown is made of metal. The vapor deposition mask 10 has a surface 10F and a back surface 10R facing the vapor deposition source. The vapor deposition mask 10 has a plurality of mask holes 11, and the mask holes 11 include a hole portion having an inverted frustum shape. In the vapor deposition mask 10, the region where the plurality of mask holes 11 are formed is the pattern region R1, and the region surrounding the pattern region R1 and where the mask holes 11 are not formed is the peripheral region R2.

[0047] In this embodiment, the plurality of mask holes 11 are arranged in a staggered pattern. Alternatively, the plurality of mask holes 11 may be arranged in a pattern other than the staggered pattern. The pattern other than the staggered pattern may be, for example, a square grid.

[0048] The evaporation mask 10 has a thickness T of, for example, 1 μm or more and 20 μm or less. The thickness of the pattern region R1 may be smaller than the thickness of the peripheral region R2. In this case, the thickness of the evaporation mask 10 is the thickness of the peripheral region R2, and the material forming the evaporation mask 10 is an iron-nickel alloy. The iron-nickel alloy may be, for example, an alloy containing 36% by mass of nickel, i.e., Invar alloy. In other words, the evaporation mask 10 is substantially composed of an iron-nickel alloy.

[0049] Figure 2 The shape of the mask hole 11 viewed from a viewpoint facing the surface 10F of the vapor deposition mask 10 is shown.

[0050] like Figure 2 As shown, the mask hole 11 includes a small opening 11S and a large opening 11L. The small opening 11S is an opening on one side of the hole portion. When viewed from a viewpoint opposite to the surface 10F, the large opening 11L surrounds the small opening 11S. In the present embodiment, the small opening 11S is located on the back side 10R of the vapor deposition mask 10. When viewed from a viewpoint opposite to the surface 10F of the vapor deposition mask 10, the small opening 11S has a polygonal edge 11SE including a plurality of corners 11SC and linear portions 11SL located between the corners 11SC.

[0051] In the present embodiment, the edge 11SE of the small opening 11S has a quadrilateral shape. The edge 11SE of the small opening 11S has four linear portions 11SL and four corner portions 11SC. The four linear portions 11SL include two pairs of linear portions 11SL that are parallel to each other, and the linear portions 11SL included in each group extend in a direction orthogonal to the linear portions 11SL included in the other groups. Each corner portion 11SC is a line segment having a predetermined curvature and sandwiched by the linear portions 11SL extending in directions orthogonal to each other. In the small opening 11S, the distance between the linear portions 11SL that are parallel to each other is the small opening width WS.

[0052] The large opening 11L is the other opening of each hole portion. The large opening 11L has an edge 11LE in a shape formed by the corners of the polygonal shape of the edge 11SE of the small opening 11S extending toward the outside of the polygonal shape. That is, the large opening 11L has an edge 11LE in a shape formed by the corners 11SC of the edge 11SE of the small opening 11S extending outward relative to the edge 11SE of the small opening 11S. The large opening 11L is located on the surface 10F of the vapor deposition mask 10. When viewed from a viewpoint opposite to the surface 10F of the vapor deposition mask 10, the large opening 11L has an edge 11LE in a shape formed by the same number of corners 11LC as the small opening 11S. When viewed from a viewpoint opposite to the surface 10F, the maximum value of the distance between the corners 11SC of the edge 11SE of the small opening 11S and the corners 11LC of the edge 11LE of the large opening 11L is the distance between the corners DC.

[0053] In this embodiment, when viewed from a viewpoint opposite to the surface 10F of the vapor deposition mask 10, the edge 11LE of the large opening 11L includes four linear portions 11LL and four corner portions 11LC. The four linear portions 11LL include two pairs of linear portions parallel to each other, and the linear portions 11LL included in each group extend in a direction orthogonal to the linear portions 11LL included in the other groups. When viewed from a viewpoint opposite to the surface 10F of the vapor deposition mask 10, the four linear portions 11LL are included in a virtual edge VE having a shape substantially similar to that of the small opening 11S.

[0054] The edge 11LE of the large opening 11L also has four extensions 11LP extending from the virtual edge VE in a direction away from the small opening 11S. Each extension 11LP is clamped by two linear portions 11LL that are orthogonal to each other. When viewed from a viewpoint opposite to the surface 10F of the vapor deposition mask 10, the area divided by each extension 11LP has a roughly triangular shape. Each corner 11LC belongs to a different extension 11LP. When viewed from a viewpoint opposite to the surface 10F of the vapor deposition mask 10, each corner 11LC includes a portion of the extension 11LP to which the corner 11LC belongs that is the farthest away from the small opening 11S. Among the extensions 11LP, the angle of the corner 11LC is the third angle θ3. The third angle θ3 is an angle formed by the two linear portions that clamp the corner 11LC. Specifically, it is an angle formed by the connection lines of the respective extensions 11LP at the intersection of the virtual edge VE and the extension 11LP.

[0055] The side surface 11SD that divides the mask hole 11 connects the large opening 11L and the small opening 11S. The side surface 11SD has an inclination that decreases the area of ​​the mask hole 11 in a cross section parallel to the surface 10F of the vapor deposition mask 10 from the large opening 11L toward the small opening 11S. That is, the mask hole 11 has an inverted frustum shape in a cross section orthogonal to the surface 10F of the vapor deposition mask 10. Therefore, in the present embodiment, each mask hole 11 is formed by one hole portion having an inverted frustum shape.

[0056] Hereinafter, referring to the cross-sectional structure of the vapor deposition mask 10, Figure 3 as well as Figure 4 , the shape of the mask hole 11 is described in more detail. In addition, Figure 3 Shown along Figure 2 The cross section of the III-III line shown is the structure of the vapor deposition mask 10 in the cross section along the diagonal direction of the small opening 11S. Figure 4 Shown along Figure 2 The cross section shown is taken along line IV-IV and is the structure of the vapor deposition mask 10 in a cross section along a direction perpendicular to one linear portion 11SL in an edge 11SE of a small opening 11S.

[0057] like Figure 3 As shown, in the cross section perpendicular to the surface 10F of the vapor deposition mask 10 and along the diagonal direction of the small opening 11S, the virtual straight line connecting the corner 11SC in the edge 11SE of the small opening 11S and the corner 11LC in the edge 11LE of the large opening 11L is the first virtual straight line L1. The first virtual straight line L1 is a virtual straight line connecting the corner 11SC of the small opening 11S and the corner 11LC of the large opening 11L corresponding to the corner 11SC of the small opening 11S. That is, the first virtual straight line L1 is a virtual straight line connecting the corner 11SC of the small opening 11S and the corner 11LC of the large opening 11L that is the smallest distance from the corner 11SC when viewed from a viewpoint opposite to the surface of the vapor deposition mask 10.

[0058] exist Figure 3 In the example shown, the side surface 11SD that partitions the mask hole 11 has an arc shape that is recessed toward the back surface 10R compared to the first virtual straight line L1. In addition, in a cross section that is orthogonal to the surface 10F of the vapor deposition mask 10 and along the diagonal direction of the small opening 11S, the side surface 11SD that partitions the mask hole 11 may also have an arc shape that is protruding toward the surface 10F compared to the first virtual straight line L1. Alternatively, the side surface 11SD may also be consistent with the first virtual straight line L1.

[0059] The angle formed by the surface 10F of the deposition mask 10 and the first virtual straight line L1 is the first angle θ1. In addition, since the surface 10F of the deposition mask 10 is substantially parallel to the back surface 10R of the deposition mask 10, the angle formed by the back surface 10R and the first virtual straight line L1 is equal to the first angle θ1.

[0060] The distance DC between corners is greater than 1 times and less than 1.5 times the distance between the surface 10F of the vapor deposition mask 10 and the plane including the edge 11SE of the small opening 11S. In the present embodiment, the distance between the surface 10F of the vapor deposition mask 10 and the plane including the edge 11SE of the small opening 11S is equal to the thickness T of the vapor deposition mask 10. As described above, the thickness T of the vapor deposition mask 10 may be, for example, greater than 1 μm and less than 20 μm. Therefore, the distance DC between corners can be any value included in the range of, for example, greater than 1 μm and less than 30 μm.

[0061] like Figure 4 As shown, in a cross section perpendicular to the surface 10F of the vapor deposition mask 10 and along a direction perpendicular to a linear portion 11SL in the edge 11SE of the small opening 11S, a virtual straight line connecting the edge 11SE of the small opening 11S and the edge 11LE of the large opening 11L is a second virtual straight line L2. Figure 4 In the example shown, the side surface 11SD that partitions the mask hole 11 has an arc shape that is recessed toward the back surface 10R compared to the second virtual straight line L2. In addition, in a cross section that is orthogonal to the surface 10F of the vapor deposition mask 10 and along a direction orthogonal to one linear portion 11SL in the edge 11SE of the small opening 11S, the side surface 11SD that partitions the mask hole 11 may have an arc shape that is protruded toward the surface 10F compared to the second virtual straight line L2. Alternatively, the side surface 11SD may coincide with the second virtual straight line L2.

[0062] The angle formed by the surface 10F of the vapor deposition mask 10 and the second virtual straight line L2 is the second angle θ2. In addition, since the surface 10F of the vapor deposition mask 10 is substantially parallel to the back surface 10R of the vapor deposition mask 10, the angle formed by the back surface 10R and the second virtual straight line L2 is equal to the second angle θ2. The second angle θ2 is greater than the first angle θ1.

[0063] Figure 5 A part of the small opening 11S viewed from a viewpoint facing the surface 10F of the vapor deposition mask 10 is shown in an enlarged manner.

[0064] like Figure 5 As shown and described above, the corner 11SC in the edge 11SE of the small opening 11S has a curvature. The corner 11SC has a curvature such that the center of curvature C is located within the small opening 11S. The curvature radius R of the corner 11SC is 4.5 μm or less.

[0065] [Method for producing vapor deposition mask]

[0066] Reference Figure 6 to Figure 9 A method for manufacturing the vapor deposition mask 10 will be described.

[0067] The method for manufacturing the vapor deposition mask 10 includes the following steps: forming a resist mask on at least one of the front surface and the back surface of a metal sheet; and forming a plurality of mask holes on the metal sheet using the resist mask. The method for manufacturing the vapor deposition mask 10 will be described in more detail below with reference to the accompanying drawings. Figure 6 , Figure 7 and Fig. 9 In the figure, for the convenience of illustration, the mask holes formed on the metal sheet are schematically shown.

[0068] like Figure 6 As shown, when manufacturing the vapor deposition mask 10, first prepare a metal sheet 10M. The material forming the metal sheet 10M is, for example, an iron-nickel alloy. The iron-nickel alloy may be, for example, Invar alloy. The metal sheet 10M has, for example, a thickness of 1 μm or more and 50 μm or less. In addition, when the thickness of the metal sheet 10M is greater than the thickness T of the vapor deposition mask 10, the metal sheet 10M can be etched before forming a resist layer on the metal sheet 10M, thereby reducing the thickness of the metal sheet 10M to the thickness required by the vapor deposition mask 10.

[0069] Next, a resist layer RL is formed on the surface 10MF of the metal sheet 10M. The resist layer RL may be formed by a positive resist or a negative resist. The resist layer RL may be formed on the surface 10MF of the metal sheet 10M by attaching a dry film resist to the surface 10MF of the metal sheet 10M. Alternatively, the resist layer RL may be formed by applying a coating liquid including a material for forming the resist layer RL to the surface 10MF of the metal sheet 10M.

[0070] like Figure 7 As shown, by performing exposure and development on the resist layer RL, a resist mask RM is formed through the resist layer RL. The resist mask RM has a mask hole RMh having a shape corresponding to the shape of the mask hole formed in the metal sheet 10M.

[0071] Figure 8 The planar structure of the resist mask RM observed from a viewpoint facing the surface 10MF of the metal sheet 10M is shown. Figure 8 The shape of the mask hole RMh of the illustrated resist mask RM is an example of a possible shape of the mask hole RMh.

[0072] like Figure 8As shown, the mask hole RMh has an edge RMhE that divides the mask hole RMh. The edge RMhE of the mask hole RMh has a shape in which the corners at the polygonal virtual edge RMhV protrude toward the outside of the polygon. Figure 8 In the example shown, the edge RmhE of the mask hole RMh has a shape formed by the corner portion at the virtual edge RMhV of the quadrilateral protruding toward the outside of the quadrilateral. The shape of the edge RmhE of the mask hole RMh is substantially equal to the shape of the edge 11LE of the large opening 11L formed using the resist mask RM. In addition, the shape of the virtual edge RMhV is substantially equal to the shape of the edge 11SE of the small opening 11S.

[0073] The edge RmhE of the mask hole RMH has four protruding portions RMHP and four linear portions RMhL. At the edge RmhE of the mask hole RMH, one protruding portion RMHP is clamped by two linear portions RMHL. The virtual edge RMhV includes four linear portions RMhL. Each protruding portion RMHP has one corner portion RMhC. When observed from a viewpoint opposite to the surface 10MF of the metal sheet 10M, the area divided by each protruding portion RMhP has a roughly triangular shape. The shape of each protruding portion RMHP is roughly equal to the shape of the protruding portion 11LP of the edge 11LE of the large opening 11L.

[0074] In the mask hole RMh, the distance between two linear portions RMhL that are substantially parallel to each other is the mask hole width WRMh. The distance between the corner of the virtual edge RMhV and the corner RMhC of the extension RMhP formed when the corner is extended is the corner correction value RMhDC. In the extension RMhP, the angle of the corner RMhC is the fourth angle θ4. In the mask hole RMh, the shape of the mask hole formed in the metal sheet 10M is changed by changing at least one of the mask hole width WRMh, the corner correction value RMhDC, and the fourth angle θ4.

[0075] like Fig. 9 As shown, a plurality of mask holes 11M are formed on the metal sheet 10M by wet etching using the resist mask RM. Thus, the mask holes 11M having openings are formed on the surface 10MF and the back surface 10MR of the metal sheet 10M. By removing the resist mask RM from the metal sheet 10M, the above-mentioned evaporation mask 10 is obtained. In addition, in the metal sheet 10M, the surface 10MF corresponds to the surface 10F of the evaporation mask 10, the back surface 10MR corresponds to the back surface 10R of the evaporation mask 10, and the mask holes 11M correspond to the mask holes 11 of the evaporation mask 10.

[0076] [Mask device]

[0077] Reference Fig.10, illustrating the mask device.

[0078] like Fig.10 As shown, the mask device 20 includes a frame 21 and a plurality of vapor deposition masks 10. Fig.10 In the example shown, the mask device 20 includes three vapor deposition masks 10, but the mask device 20 may include two or less vapor deposition masks 10, or may include four or more vapor deposition masks 10. The frame 21 has a rectangular frame shape capable of supporting a plurality of vapor deposition masks 10. The frame 21 is mounted on the vapor deposition device for vapor deposition. The frame 21 covers substantially the entire range where each vapor deposition mask 10 is located, and has a frame hole 21H that penetrates the frame 21.

[0079] Each vapor deposition mask 10 has a strip shape extending in one direction. Each vapor deposition mask 10 has a plurality of pattern regions R1 and a peripheral region R2 surrounding the pattern regions R1. Fig.10 In the illustrated example, the vapor deposition mask 10 has three pattern regions R1 , but the vapor deposition mask 10 may have two or less pattern regions R1 , or may have four or more pattern regions R1 .

[0080] In the peripheral region R2 of each vapor deposition mask 10, a pair of portions sandwiching the plurality of pattern regions R1 in the direction in which the vapor deposition mask 10 extends are fixed to the frame 21. The vapor deposition mask 10 is fixed to the frame 21 by bonding, welding, or the like.

[0081] The method of manufacturing a display device using the vapor deposition mask 10 includes the steps of: preparing the vapor deposition mask 10 manufactured by the above-mentioned method of manufacturing the vapor deposition mask 10 ; and forming a pattern by vapor deposition using the vapor deposition mask 10 .

[0082] In the manufacturing method of the display device, the mask device 20 equipped with the evaporation mask 10 is first installed in the vacuum chamber of the evaporation device. At this time, the mask device 20 is installed in the vacuum chamber in such a manner that the evaporation object such as a glass substrate is opposite to the back side 10R and the evaporation source is opposite to the surface 10F. Then, the evaporation object is moved into the vacuum chamber of the evaporation device, and the evaporation material is sublimated by the evaporation source. As a result, a pattern having a shape following the small opening 11S is formed in the area of ​​the evaporation object opposite to the small opening 11S. In the present embodiment, the evaporation material is an organic light-emitting material for forming pixels of an organic EL display device as an example of a display device. In addition, the evaporation material may also be a conductive material for forming a pixel electrode possessed by a pixel circuit of a display device.

[0083] [Example]

[0084] The embodiments are described with reference to Tables 1 to 3.

[0085] [Example 1]

[0086] A metal sheet made of Invar with a thickness of 20 μm was prepared. The metal sheet was etched using 48% ferric chloride to reduce the thickness of the metal sheet to 3.5 μm. Next, a positive resist (THMR-iP5700, manufactured by Tokyo Ohka Kogyo Co., Ltd.) (THMR is a registered trademark) was used to form a resist layer on the surface of the metal sheet. The resist layer was then exposed and developed to form a resist mask. Thus, when observed from a viewpoint opposite to the surface of the resist mask, a resist layer having the same thickness as the resist mask was formed. Figure 8 The mask holes shown are the same shape as the mask holes in the resist mask.

[0087] In Example 1, as shown in Table 1 below, it was confirmed that in one mask hole, the mask hole width WRMh was 18.3 μm, the corner correction value RMhDC was 3.3 μm, and the design value of the fourth angle θ4 was 30.2°. Thus, a plurality of mask holes were formed in such a manner that the target value of the small opening width WS of the vapor deposition mask was 20 μm and the target value of the gap between the mask holes was 30 μm.

[0088] Then, a plurality of mask holes were formed in the metal sheet by wet etching using a resist mask. At this time, 48% ferric chloride was used as an etching solution. In the etching of the metal sheet, the etching time of the metal sheet was set to 2, while the time for the hole formed in the metal sheet to reach the back of the metal sheet was set to 1. That is, the etching time was set to a length corresponding to the thickness T of the metal sheet to be wet-etched. Finally, the resist mask was removed from the metal sheet by immersing the etched metal sheet in a 10% sodium hydroxide aqueous solution at 60°C for 2 minutes. Thus, the vapor deposition mask of Example 1 was obtained.

[0089] [Example 2]

[0090] In Example 1, the deposition mask of Example 2 was obtained by the same method as in Example 1 except that the thickness of the metal sheet was reduced from 20 μm to 4.0 μm, the mask hole width WRMh was 18.0 μm, the corner correction value RMhDC was 3.0 μm, and the fourth angle θ4 was 30.1°.

[0091] [Example 3]

[0092] In Example 1, the deposition mask of Example 3 was obtained by the same method as Example 1, except that the thickness of the metal sheet was reduced from 20 μm to 4.5 μm, the mask hole width WRMh was 17.8 μm, the corner correction value RMhDC was 2.8 μm, and the fourth angle θ4 was 30.2°.

[0093] [Example 4]

[0094] In Example 2, a vapor deposition mask of Example 4 was obtained by the same method as in Example 2 except that the corner correction value RMhDC was 2.0 μm and the fourth angle θ4 was 30.3°.

[0095] [Example 5]

[0096] In Example 2, a vapor deposition mask of Example 5 was obtained by the same method as in Example 2 except that the corner correction value RMhDC was 2.5 μm and the fourth angle θ4 was 29.9°.

[0097] [Example 6]

[0098] In Example 4, a vapor deposition mask of Example 6 was obtained by the same method as in Example 4 except that the corner correction value RMhDC was 1.5 μm and the fourth angle θ4 was 29.8°.

[0099] [Example 7]

[0100] In Example 1, a vapor deposition mask of Example 7 was obtained by the same method as in Example 1 except that the corner correction value RMhDC was 4.3 μm and the fourth angle θ4 was 30.0°.

[0101] [Comparative Example 1]

[0102] In Example 1, a vapor deposition mask of Comparative Example 1 was obtained by the same method as in Example 1 except that the corner correction value RMhDC was 0.8 μm and the fourth angle θ4 was 29.9°.

[0103]

Table 1

[0104]

[0105] [Measurement results]

[0106] Various dimensions and the like were measured using a confocal laser microscope (OLS-4000, manufactured by Olympus Corporation) for the vapor deposition masks of Examples 1 to 7 and the vapor deposition mask of Comparative Example 1. The measurement results of each vapor deposition mask are shown in Table 2 below.

[0107]

Table 2

[0108]

[0109] As shown in Table 2, in the vapor deposition mask of Example 1, through the transmission image photographed from the direction opposite to the back side, it was confirmed that small openings with a width of approximately 20 μm and a roughly square shape were arranged in a square grid at intervals of approximately 10 μm. In addition, the distance between a pair of linear portions parallel to each other was measured as the width of the small opening. Moreover, in the vapor deposition masks of Examples 2 to 6 and the vapor deposition mask of Comparative Example 1, it was confirmed that small openings with a width of approximately 20 μm and a roughly square shape were also arranged in a square grid at intervals of approximately 10 μm. In contrast, in the vapor deposition mask of Example 7, it was confirmed that although the width of each small opening was approximately 20 μm, the etching of the corners progressed excessively, resulting in the edge of each small opening having a quadrilateral shape that was necked in both the left-right direction and the up-down direction.

[0110] Furthermore, it was confirmed that the edge of the large opening had a shape in which the corners of the quadrilateral shape protruded outward from the square shape in Examples 1 to 7. In contrast, in Comparative Example 1, it was confirmed that the edge of the large opening had a substantially square shape, and the corners of the square shape did not protrude outward from the square shape.

[0111] The first angle θ1 was confirmed to be 30.2° in Example 1, 31.1° in Example 2, and 30.5° in Example 3. Furthermore, the first angle θ1 was confirmed to be 31.0° in Example 4, and 30.1° in Example 5. Furthermore, the first angle θ1 was confirmed to be 45.0° in Example 6, 29.9° in Example 7, and 45.2° in Comparative Example 1.

[0112] The second angle θ2 was confirmed to be 45.1° in Example 1, 44.8° in Example 2, and 44.7° in Example 3. Furthermore, the second angle θ2 was confirmed to be 45.2° in Example 4, and 45.3° in Example 5. Furthermore, the second angle θ2 was confirmed to be 44.9° in Example 6, 44.7° in Example 7, and 45.0° in Comparative Example 1.

[0113] Thus, it was confirmed that the second angle θ2 was larger than the first angle θ1 in the deposition masks of Examples 1 to 5 and the deposition mask of Example 7. In contrast, in Example 6 and Comparative Example 1, it was confirmed that the first angle θ1 was larger than the second angle θ2.

[0114] The corner distance DC was confirmed to be 4.9 μm in Examples 1 and 2, 5.1 μm in Example 3, 4.0 μm in Example 4, and 4.6 μm in Example 5. Furthermore, the corner distance DC was confirmed to be 3.3 μm in Example 6, 6.2 μm in Example 7, and 2.6 μm in Comparative Example 1.

[0115] That is, it was confirmed that the ratio of the distance DC between corners to the thickness T of the vapor deposition mask (DC / T) was 1.4 in Example 1, 1.2 in Example 2, and 1.1 in Example 3. Furthermore, it was confirmed that the ratio of the distance DC between corners to the thickness T of the vapor deposition mask was 1.0 in Example 4 and 1.2 in Example 5. Furthermore, it was confirmed that the ratio of the distance DC between corners to the thickness T of the vapor deposition mask was 0.8 in Example 6, 1.8 in Example 7, and 0.7 in Comparative Example 1. Thus, it was confirmed that: in the vapor deposition masks of Examples 1 to 5, the ratio of the distance DC between corners to the thickness T of the vapor deposition mask was included in the range of 1 to 1.5, while on the other hand, in the vapor deposition masks of Examples 6 and 7 and the vapor deposition mask of Comparative Example 1, the ratio of the distance DC between corners to the thickness T of the vapor deposition mask was not included in the range of 1 to 1.5.

[0116] Furthermore, it was confirmed that the radius of curvature R of the corner of the edge of the small opening was 3.0 μm in Example 1, 3.2 μm in Example 2, and 3.9 μm in Example 3. Furthermore, it was confirmed that the radius of curvature R was 4.4 μm in Example 4, 3.8 μm in Example 5, and 7.2 μm in Example 6. Furthermore, it was confirmed that the radius of curvature R was 8.5 μm in Comparative Example 1. Thus, it was confirmed that in the vapor deposition masks of Examples 1 to 5, the radius of curvature R was less than 4.5 μm, while on the other hand, in the vapor deposition masks of Example 6 and Comparative Example 1, the radius of curvature R exceeded 4.5 μm. In addition, it was confirmed that in Example 7, the edge of the small opening had a constriction in both the left-right direction and the up-down direction, and had no curvature at the corner.

[0117] Furthermore, it was confirmed that the third angle θ3 was 51.6° in Example 1, 51.5° in Example 2, and 51.6° in Example 3. It was confirmed that the third angle θ3 was 51.8° in Example 4, 51.1° in Example 5, and 51.0° in Example 6. It was confirmed that the third angle θ3 was 51.3° in Example 7 and 51.1° in Comparative Example 1. In addition, the third angle θ3 in Comparative Example 1 was set to an angle in the corner portion of the large opening.

[0118] [Evaluation results]

[0119] Deposition patterns were formed on the deposition object using the deposition masks of Examples 1 to 7 and the deposition mask of Comparative Example 1. At this time, a glass substrate was used as the deposition object, and an organic light emitting material was used as the deposition material for forming the deposition pattern.

[0120] Using each vapor deposition mask, a quadrilateral vapor deposition pattern arranged in a grid shape with 15 rows and 15 columns was formed. Then, the deviation of the film thickness was calculated for the vapor deposition pattern located in the center of the 9 rows and 9 columns of the vapor deposition pattern. At this time, the film thickness of the central part of each vapor deposition pattern was measured, and the film thickness was regarded as the maximum value MM of the film thickness of the vapor deposition pattern. In addition, the film thickness of the corner of each vapor deposition pattern was measured, and the film thickness was regarded as the minimum value Mm of the film thickness of the vapor deposition pattern. In addition, the film thickness of each vapor deposition pattern was measured using a surface shape measuring instrument (Dektak6M, manufactured by Veeco). Then, the deviation of the film thickness calculated based on the following formula (1) is set to "○" when it is less than 5%, set to "△" when it is less than 10%, and set to "×" when it exceeds 10%.

[0121] 100×{(MM-Mm) / (MM+Mm)} / 2(%)…Formula (1)

[0122] The deviation of the film thickness calculated according to the above formula (1) is as shown in Table 3 below.

[0123]

Table 3

[0124]

[0125] As shown in Table 3, the evaluation results of the vapor deposition masks of Examples 1 to 5 and 7 were "○", the evaluation result of the vapor deposition mask of Example 6 was "△", and on the other hand, the evaluation result of the vapor deposition mask of Comparative Example 1 was "×". Therefore, it was confirmed that the vapor deposition masks of Examples 1 to 7 suppressed the variation of the film thickness in the vapor deposition pattern compared with Comparative Example 1.

[0126] Furthermore, it was confirmed that there is a tendency that when the ratio of the distance DC between corners to the thickness T is less than 1, the deviation of the film thickness in the vapor deposition pattern becomes larger than when the ratio of the distance DC between corners to the thickness T is 1 or more. In this regard, it was confirmed that when the ratio of the distance DC between corners to the thickness T exceeds 1.5, the deviation of the film thickness in the vapor deposition pattern is small, and on the other hand, the edge of the vapor deposition pattern has a shape that is necked relative to the desired polygonal shape. Therefore, in order to suppress the deviation of the film thickness in the vapor deposition pattern and improve the accuracy of the shape in the vapor deposition pattern, it can be said that it is preferred that the ratio of the distance DC between corners to the thickness T is greater than 1 and less than 1.5.

[0127] Furthermore, it was confirmed that when the curvature radius R exceeded 4.5 μm, the variation of the film thickness in the vapor deposition pattern became larger than when the curvature radius R was 4.5 μm or less. In other words, in order to suppress the variation of the film thickness in the vapor deposition pattern, it can be said that the curvature radius R is preferably 4.5 μm or less.

[0128] As described above, according to one embodiment of the vapor deposition mask, the method for manufacturing the vapor deposition mask, and the method for manufacturing a display device, the effects described below can be obtained.

[0129] (1) The vapor deposition material that has entered the mask hole 11 from the vicinity of the corner 11LC of the large opening 11L can easily reach the small opening 11S, so that variations in film thickness of the vapor deposition pattern are suppressed.

[0130] (2) In the vapor deposition pattern, the film thickness at the corners is suppressed from becoming smaller than the film thickness at the center, so that the variation in the film thickness of the vapor deposition pattern can be suppressed.

[0131] (3) Since the distance between the small opening 11S and the vapor deposition object can be reduced compared to the case where the small opening 11S having a shape corresponding to the vapor deposition pattern formed on the vapor deposition object is located between the front surface 10F and the back surface 10R, the deviation of the film thickness in the vapor deposition pattern formed on the vapor deposition object can be suppressed.

[0132] (4) Compared with a case where the thickness of the vapor deposition mask 10 exceeds 20 μm, the size of the large opening 11L that can penetrate the metal sheet 10M can be reduced, so the vapor deposition mask 10 can be provided with a plurality of mask holes 11 at a higher density.

[0133] (5) Since the situation in which the difference between the expansion degree of the vapor deposition mask 10 and the expansion degree of the glass substrate becomes excessively large as the vapor deposition mask 10 and the glass substrate are heated is suppressed, the situation in which the accuracy of the vapor deposition pattern formed on the glass substrate is reduced due to the difference between the expansion rate of the vapor deposition mask 10 and the expansion rate of the glass substrate is suppressed.

[0134] In addition, the above-mentioned embodiment can be implemented by changing it as follows.

[0135] [Open mouth]

[0136] The shape of the extension portion 11LP included in the edge 11LE of the large opening 11L can be changed as follows. That is, as shown in the drawings referred to below, the region defined by the extension portion 11LP can have various shapes when viewed from a viewpoint facing the surface 10F of the deposition mask 10 .

[0137] For example, the area divided by the extension portion 11LP may be as follows: Fig.11 As shown, it has a generally rectangular shape, and can also be Fig.12 The area divided by the extension portion 11LP can be as follows: Fig.13 As shown, it has a roughly trapezoidal shape, but it can also be Fig.14 As shown in FIG. 1 , the area divided by the extension 11LP may be substantially rectangular, and the corner 11LC may be straight. Fig.15As shown in FIG. 1 , the extension portion 11LP has a substantially square shape, and the three corners of the extension portion 11LP are located outside the virtual edge VE. Alternatively, the areas divided by the extension portion 11LP may also be as follows: Fig.16 Shown as having a generally circular shape.

[0138] Even when the area divided by the extension 11LP has any of the above-mentioned shapes, the effect based on the above-mentioned (1) can be obtained by making the edge 11LE of the large opening 11L have a shape in which the polygonal corners of the edge 11SE of the small opening 11S extend outward from the polygonal shape.

[0139] Furthermore, even when the region divided by the extension 11LP has any of the above-mentioned shapes, the distance DC between the corners can be made not less than 1 times and not more than 1.5 times the thickness T of the vapor deposition mask 10. Thus, in the side surface 11SD dividing the mask hole 11, the inclination angle of the portion connecting the corner 11SC of the edge 11SE of the small opening 11S and the corner 11LC of the edge 11LE of the large opening 11L can be reduced.

[0140] [Number of corners]

[0141] The edge 11SE of the small opening 11S may have a polygonal shape other than a quadrilateral shape. The small opening 11S may have a polygonal shape having, for example, five or more corners 11SC. The edge 11LE of the large opening 11L may have, for example, five or more corners 11LC.

[0142] Fig.17 One modified example of the shape of the edge 11SE of the small opening 11S is shown.

[0143] like Fig.17 As shown, the edge 11SE of the small opening 11S has a substantially regular octagonal shape. The edge 11SE of the small opening 11S includes eight linear portions 11SL and eight corner portions 11SC. The radius of curvature R of each corner portion 11SC is 4.5 μm or less, similar to the above-mentioned embodiment.

[0144] The edge 11LE of the large opening 11L includes eight linear portions 11LL, eight corner portions 11LC, and eight protruding portions 11LP. Each corner portion 11LC belongs to a different protruding portion 11LP. The area divided by each protruding portion 11LP is Fig.11 The same modification example shown in FIG. 1 is similar to the modification example shown in FIG. 1 , and has a substantially rectangular shape, and the corner portion 11LC has a curvature. Figure 2 as well as Figures 12 to 16 And the protruding parts 11LP described above.

[0145] In addition, when the edge 11SE of the small opening 11S has a polygonal shape other than a quadrilateral shape, a first virtual straight line L1 can be defined in a cross section that is orthogonal to the surface 10F of the vapor deposition mask 10 and along a plane including one corner portion 11SC in the small opening 11S and a corner portion 11LC in the large opening 11L corresponding to the corner portion 11SC. In addition, when the edge 11SE of the small opening 11S has a polygonal shape other than a quadrilateral shape, a second virtual straight line L2 can be defined in a cross section that is orthogonal to the surface 10F of the vapor deposition mask 10 and along a plane including one linear portion 11SL in the small opening 11S and a linear portion 11LL of the large opening 11L parallel to the linear portion 11SL.

[0146] [Mask hole]

[0147] The mask hole may have two hole portions.

[0148] That is, Fig.18 As shown, the mask hole 31 of the vapor deposition mask 30 may also include a large hole portion 31a as one hole portion and a small hole portion 31b as another hole portion. The large hole portion 31a is connected to the small hole portion 31b in the middle of the thickness direction of the vapor deposition mask 30. The large hole portion 31a has a large opening 31L on the surface 30F, and has a small opening 31S as an opening on the opposite side of the large opening 31L. The small hole portion 31b shares the small opening 31S with the large hole portion 31a, and has an opening on the opposite side of the small opening 31S, that is, a back opening 31R that opens on the back side 30R. In addition, the distance between the portion where the large hole portion 31a and the small hole portion 31b are connected and the back side 30R is a step height SH. In terms of suppressing the uneven brightness caused by the shadow effect in the vapor deposition pattern, it is preferred that the step height SH is smaller. When the mask hole 31 includes two holes, the thickness of the vapor deposition mask 30 can be increased while suppressing a decrease in the resolution of the vapor deposition mask 30 .

[0149] Furthermore, the distance D between the surface 30F of the vapor deposition mask 30 and the plane including the edge of the small opening 31S is the same as in the above-mentioned embodiment, and the corner distance DC can be 1 to 1.5 times the distance D.

[0150] In this case as well, the effect of (1) can be obtained by making the large opening 31L of the vapor deposition mask 30 have a shape in which the polygonal corners of the edges of the small openings 31S extend from the polygonal shape.

[0151] The mask hole 11 included in the vapor deposition mask 10 may not satisfy at least one of the following conditions.

[0152] (Condition A) The second angle θ2 is larger than the first angle θ1.

[0153] (Condition B) The corner-to-corner distance DC is not less than 1 time and not more than 1.5 times the distance between the surface of the vapor deposition mask 10 and the plane including the edge 11SE of the small opening 11S.

[0154] (Condition C) The curvature radius R of the corner portion 11SC of the edge 11SE of the small opening 11S is 4.5 μm or less.

[0155] Even if the mask hole 11 does not satisfy at least one of conditions A to C, the effect based on the above (1) can be obtained by making the edge 11LE of the large opening 11L have a shape in which the polygonal corners of the edge 11SE of the small opening 11S extend toward the outside of the polygon.

[0156] [Material for forming the evaporation mask]

[0157] The material forming the evaporation mask 10 may be a metal other than an iron-nickel alloy. The material forming the evaporation mask 10 may be an iron-nickel-cobalt alloy, for example, an alloy containing 32% by mass of nickel and 4% or more and 5% or less of cobalt by mass, i.e., super-Invar alloy. The material forming the evaporation mask 10 may be an iron-chromium-nickel alloy, i.e., chromium-nickel stainless steel. Chromium-nickel stainless steel may be, for example, SUS304. In addition, the iron-chromium-nickel alloy has a larger thermal expansion coefficient than the iron-nickel alloy and the iron-nickel-cobalt alloy. Therefore, when the temperature rise of the evaporation mask 10 during evaporation is small, an iron-chromium-nickel alloy may be used, and when the temperature rise of the evaporation mask 10 is greater, it is preferable to use an iron-nickel alloy or an iron-nickel-cobalt alloy. Even in this case, by making the edge 11LE of the large opening 11L have a shape in which the polygonal corners of the edge 11SE of the small opening 11S extend outward from the polygonal shape, the effect based on the above (1) can be obtained.

[0158] [Thickness of deposition mask]

[0159] The thickness of the deposition mask may be thicker than 20 μm. Even in this case, the effect of (1) can be obtained by making the edge 11LE of the large opening 11L have a shape in which the polygonal corners of the edge 11SE of the small opening 11S protrude toward the outside of the polygonal shape.

[0160] [Evaporation mask]

[0161] The vapor deposition mask 10 may also include a mask portion corresponding to the pattern region R1 and a sub-frame corresponding to the peripheral region R2. In this case, the sub-frame is a separate body from the mask portion, and the sub-frame has a sub-frame hole. Then, each mask portion is mounted relative to the sub-frame in a manner of blocking mutually different sub-frame holes. As a result, in the vapor deposition mask 10, the number of mask portions and the number of sub-frame holes become the same. The mask portion may be mounted on the sub-frame by bonding or by welding.

[0162] In addition, since the mask portion can be supported by the sub-frame in this case, the thickness of the mask portion can be reduced compared to the case where the mask portion and the peripheral portion are integrated. When forming the mask portion, the thickness of the mask portion can be reduced by etching both sides of the mask portion before forming the mask hole in the mask portion. In addition, in the case of forming a thin mask portion, in order to improve the mountability of the mask portion, the mask portion can be stacked on a support layer that supports the mask portion during etching for reducing the thickness of the mask portion and etching for forming the mask hole in the mask portion. The support layer can be removed from the mask portion as long as the mask portion is mounted on the sub-frame.

[0163] Description of Reference Numerals

[0164] 10, 30…evaporation mask, 10F, 10MF, 30F…surface, 10M…metal sheet, 10MR, 10R, 30R…back surface, 11, 11M, 31, RMH…mask hole, 11L, 31L…large opening, 11LC, 11SC, RMHC…corner, 11LE, 11SE, RMHE…edge, 11LL, 11SL, RMHL…linear portion, 11LP, RMHP…extending portion, 11S, 31S…small opening, R…radius of curvature, L1…first virtual straight line, L2…second virtual straight line, θ1…first angle, θ2…second angle

Claims

1. A vapor deposition mask, which is a metal vapor deposition mask, characterized in that: have: A surface configured to face a vapor deposition source; and The plurality of mask holes each include a hole portion having an inverted frustum shape, The hole portion of each mask hole has: The small opening has a polygonal edge including a plurality of corners and a plurality of linear portions respectively located between adjacent corners when viewed from a viewpoint opposite to the surface of the vapor deposition mask; and a large opening located on the surface, wherein an edge of the large opening has an edge of a shape such that, when viewed from a viewpoint opposite to the surface, only a corner of a shape similar to the edge of the small opening protrudes outward relative to a shape similar to the edge of the small opening, When viewed from a viewpoint opposite to the surface, the large opening surrounds the small opening.

2. The evaporation mask according to claim 1, characterized in that The vapor deposition mask further includes a back surface which is a surface opposite to the front surface. The plurality of small openings are located on the back side.

3. The vapor deposition mask according to claim 1 or 2, characterized in that: The vapor deposition mask has a thickness of 1 μm to 20 μm.

4. The vapor deposition mask according to claim 1 or 2, characterized in that: The material forming the above-mentioned evaporation mask is an iron-nickel alloy or an iron-nickel-cobalt alloy.

5. A method for manufacturing a vapor deposition mask, comprising the following steps: forming a resist mask on at least one of a front surface and a back surface of the metal sheet; and Using the resist mask, a plurality of mask holes are formed in the metal sheet. The step of forming the plurality of mask holes is to form the plurality of mask holes each including a hole portion having an inverted frustum shape on the metal sheet in the following manner: The hole portion of each mask hole has: The small opening has a polygonal edge including a plurality of corners and a plurality of linear portions respectively located between adjacent corners when viewed from a viewpoint opposite to the plane in which the metal sheet extends; and a large opening located on the surface, wherein an edge of the large opening has an edge of a shape such that, when viewed from a viewpoint opposite to the surface, only a corner portion of a shape similar to the edge of the small opening protrudes outward relative to a shape similar to the edge of the small opening, When viewed from a viewpoint opposite to the surface, the large opening surrounds the small opening.

6. A method for manufacturing a display device, comprising the following steps: preparing a vapor deposition mask manufactured by the method for manufacturing a vapor deposition mask according to claim 5; and A pattern is formed by vapor deposition using the above-mentioned vapor deposition mask.

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