JP7501709B2 - mask - Google Patents

Description

An embodiment of the present disclosure relates to a mask having a metal plate with through holes.

It is preferable that display devices used in portable devices such as smartphones and tablet PCs have high resolution, for example, a pixel density of 400 ppi or more. There is also an increasing demand for portable devices to support ultra-high definition (UHD), and in this case, it is preferable that the pixel density of the display device is, for example, 800 ppi or more.

Among display devices, organic EL display devices have been attracting attention due to their good responsiveness, low power consumption, and high contrast. A method for forming pixels in an organic EL display device is known in which a mask with through-holes arranged in a desired pattern is used to form pixels in the desired pattern. Specifically, the mask is first combined with a substrate for the organic EL display device. Next, a deposition material containing an organic material is attached to the substrate through the through-holes in the mask. By carrying out such a deposition process, pixels having a deposition layer containing the deposition material can be formed on the substrate in a pattern corresponding to the pattern of the through-holes in the mask.

A method for manufacturing a mask is known in which a through hole is formed in a metal plate by etching using photolithography technology. For example, first, a first resist layer is formed on a first surface of the metal plate, and a second resist layer is formed on a second surface of the metal plate. Next, an area of the first surface of the metal plate that is not covered by the first resist layer is etched to form a first recess in the first surface of the metal plate. After that, an area of the second surface of the metal plate that is not covered by the second resist layer is etched to form a second recess in the second surface of the metal plate. At this time, etching is performed so that the first recess and the second recess communicate with each other, thereby forming a through hole that penetrates the metal plate.

Patent No. 5382259

When manufacturing a mask by etching the area of the second surface of the metal plate that is not covered by the second resist layer, the cross-sectional shape of the end of the through hole located on the opposite side to the substrate tends to become sharp. In this case, foreign matter tends to become entangled in the end of the through hole when the mask is cleaned.

The present disclosure aims to provide a mask that can effectively solve these problems.

According to one embodiment of the present disclosure, a mask comprises:
The metal plate includes a first surface, a second surface located opposite to the first surface, and a through hole, and has a thickness of 10 μm or less;
the through hole has a wall surface including a first end that is an end on the first surface and a second end that is an end on the second surface,
the wall surface is located between the first end and the second end in a thickness direction of the metal plate and includes a minimum opening diameter portion having a smallest opening diameter,
a distance between the minimum opening diameter portion and the first end in a thickness direction of the metal plate is 2.0 μm or less;
The second end has a curved cross-sectional shape.

In accordance with one embodiment of the present disclosure, there is provided a mask comprising:
The metal plate may have a thickness of 2 μm or less.

In accordance with one embodiment of the present disclosure, there is provided a mask comprising:
A distance between the minimum opening diameter portion and the first end in a thickness direction of the metal plate may be 0.1 μm or more.

In accordance with one embodiment of the present disclosure, there is provided a mask comprising:
A ratio of a distance between the minimum opening diameter portion and the first end in a thickness direction of the metal plate to a thickness of the metal plate may be 0.1 or more and 0.4 or less.

In accordance with one embodiment of the present disclosure, there is provided a mask comprising:
The second surface of the metal plate located between two of the through holes may be flat.

In accordance with one embodiment of the present disclosure, there is provided a mask comprising:
An angle formed between a direction in which a straight line passing through the minimum opening diameter portion and the second end extends and a surface direction of the first surface may be 80° or less.

In accordance with one embodiment of the present disclosure, there is provided a mask comprising:
The metal plate may comprise an iron alloy containing 34% to 38% by weight nickel.

In accordance with one embodiment of the present disclosure, there is provided a mask comprising:
The through hole may have a minimum opening dimension of 50 μm or less.

The mask according to the embodiment of the present disclosure can prevent foreign matter from becoming entangled at the end of the through-hole when cleaning the mask.

FIG. 1 is a diagram showing a deposition apparatus including a deposition mask device according to an embodiment of the present disclosure. FIG. 1 is a plan view showing a deposition mask apparatus according to an embodiment of the present disclosure. 3B is a plan view showing an effective area of the deposition mask of the deposition mask device of FIG. 3A as viewed from the second surface side. FIG. 3C is a plan view showing a modified example of an arrangement of effective areas of a deposition mask of the deposition mask device in FIG. 3B. FIG. 3B is a cross-sectional view taken along line AA in FIG. 3A. 4 is an enlarged cross-sectional view showing a through hole and a shielding portion. FIG. FIG. 4 is an enlarged plan view showing a through hole. 4 is an enlarged cross-sectional view showing a shielding portion that defines a through hole. FIG. 10 is a cross-sectional view showing a further enlarged view of a shielding portion that defines a through hole. FIG. 1A to 1C are diagrams illustrating a process of forming a resist layer on a metal plate. 1A to 1C are diagrams illustrating a step of patterning a resist layer. FIG. 2 is a diagram illustrating a first etching step. FIG. FIG. 4 illustrates a second etching step. FIG. 4 illustrates a second etching step. FIG. 13 is a diagram showing a filler removal step. FIG. 11 is a diagram showing a step of patterning a resist layer in a comparative example. FIG. 13 is a diagram showing a process for etching a metal plate in a comparative example. FIG. 1 is a cross-sectional view showing a deposition substrate produced using a mask. FIG. 2 is an enlarged cross-sectional view showing a deposition layer formed by a deposition process. FIG. 2 is a cross-sectional view showing a deposition mask produced in Example 1. FIG. 11 is a cross-sectional view showing a deposition mask produced in Example 2. FIG. 11 is a cross-sectional view showing a deposition mask produced in Example 3.

The configuration of a mask according to one embodiment and a method for manufacturing the same will be described in detail below with reference to the drawings. Note that the following embodiment is an example of an embodiment of the present disclosure, and the present disclosure is not to be interpreted as being limited to these embodiments. In this specification, the terms "plate," "substrate," "sheet," "film," and the like are not distinguished from each other based only on the difference in name. For example, "plate" is a concept that includes members that can be called sheets and films. In addition, the term "surface (sheet surface, film surface)" refers to a surface that coincides with the planar direction of the target plate-like member (sheet-like member, film-like member) when the target plate-like (sheet-like, film-like) member is viewed overall and in a global perspective. In addition, the normal direction used for a plate-like (sheet-like, film-like) member refers to the normal direction to the surface (sheet surface, film surface) of the member. Furthermore, terms such as "parallel" and "orthogonal," and values of lengths and angles, which specify the shape and geometric conditions and their degrees, as used in this specification, are to be interpreted without being bound by strict meanings, but including a range in which similar functions can be expected.

In addition, in the drawings referred to in this embodiment, identical parts or parts having similar functions are given the same or similar symbols, and repeated explanations may be omitted. Also, the dimensional ratios of the drawings may differ from the actual ratios for the convenience of explanation, and some components may be omitted from the drawings.

The embodiments of the present disclosure may be combined with other embodiments or variations as long as no contradictions arise. In addition, other embodiments may be combined with each other, or other embodiments may be combined with variations as long as no contradictions arise. In addition, variations may be combined with each other as long as no contradictions arise.

In addition, in an embodiment of the present disclosure, when multiple steps are disclosed in a method such as a manufacturing method, other steps that are not disclosed may be performed between the disclosed steps. In addition, the order of the disclosed steps may be arbitrary as long as no contradictions arise.

In this embodiment, an example will be described in which the mask is a deposition mask used to pattern an organic material in a desired pattern on a substrate when manufacturing an organic EL display device. However, the use of the mask is not particularly limited, and this embodiment can be applied to masks used for various purposes. For example, the mask of this embodiment may be used to manufacture a device for displaying or projecting images or videos to represent virtual reality, so-called VR, or augmented reality, so-called AR.

First, a deposition apparatus 80 for performing a deposition process in which a deposition material is deposited on a target object will be described with reference to FIG. 1. As shown in FIG. 1, the deposition apparatus 80 may include an evaporation source (e.g., a crucible 81), a heater 83, and an evaporation mask device 10 therein. The deposition apparatus 80 may further include an exhaust means for creating a vacuum atmosphere inside the deposition apparatus 80. The crucible 81 contains an evaporation material 82 such as an organic light-emitting material. The heater 83 heats the crucible 81 to evaporate the evaporation material 82 under a vacuum atmosphere. The evaporation mask device 10 is disposed to face the crucible 81.

The deposition mask device 10 will be described below. As shown in FIG. 1, the deposition mask device 10 includes at least one deposition mask 20. The deposition mask device 10 may further include a frame 15 that supports the deposition mask 20. The frame 15 supports the deposition mask 20 in a state where it is pulled in the direction of its surface so that the deposition mask 20 does not bend.

As shown in FIG. 1, the deposition mask device 10 is placed in the deposition device 80 so that the deposition mask 20 faces the substrate 91, which is the object to which the deposition material 82 is to be attached. The deposition mask 20 has a plurality of through holes 40 that allow the deposition material 82 flying from the deposition source 81 to pass through. In the following description, of the surfaces of the deposition mask 20, the surface located on the side of the substrate 91 to which the flying deposition material 82 is to be attached is referred to as the first surface 201, and the surface located on the opposite side of the first surface 201 is referred to as the second surface 202.

As shown in FIG. 1, the deposition mask device 10 may include a magnet 85 arranged on the surface of the substrate 91 opposite the deposition mask 20. By providing the magnet 85, the deposition mask 20 can be attracted to the magnet 85 by magnetic force, and the deposition mask 20 can be closely attached to the substrate 91. This makes it possible to suppress the occurrence of shadows in the deposition process, and to improve the dimensional accuracy and positional accuracy of the deposition layer formed on the substrate 91 by the deposition material 82 adhering to the substrate 91. In addition, the deposition mask 20 may be closely attached to the substrate 91 using an electrostatic chuck that utilizes electrostatic force.

Figure 2 is a plan view showing the deposition mask device 10 as viewed from the first surface 201 side of the deposition mask 20. As shown in Figure 2, the deposition mask device 10 may include multiple deposition masks 20. In this embodiment, each deposition mask 20 has a rectangular shape extending in one direction. In the deposition mask device 10, the multiple deposition masks 20 are arranged in a width direction that intersects with the length direction of the deposition mask 20. Each deposition mask 20 is fixed to the frame 15 at both ends in the length direction of the deposition mask 20, for example, by welding.

The deposition mask 20 shown in FIG. 2 has a pair of ears 21 fixed to the frame 15 by welding or the like, and an intermediate portion 22 located between the ears 21. The intermediate portion 22 may have at least one effective area 23 and a peripheral area 24 located around the effective area 23. In the example shown in FIG. 2, the intermediate portion 22 includes a plurality of effective areas 23 arranged at a predetermined interval along the length direction of the deposition mask 20. The peripheral area 24 surrounds the plurality of effective areas 23.

When a display device such as an organic EL display device is manufactured using the deposition mask 20, one effective area 23 corresponds to the display area of one organic EL display device. Therefore, the deposition mask device 10 shown in FIG. 2 allows deposition of multiple surfaces of an organic EL display device. Note that one effective area 23 may correspond to multiple display areas. Although not shown, multiple effective areas 23 may also be arranged at a predetermined interval in the width direction of the deposition mask 20.

The effective area 23 has, for example, a substantially quadrangular shape in plan view, or more precisely, a substantially rectangular outline in plan view. Although not shown, each effective area 23 can have an outline of various shapes depending on the shape of the display area of the organic EL display device. For example, each effective area 23 may have a circular outline.

3A is a plan view showing the effective area 23 of the deposition mask 20 as viewed from the second surface 202 side. FIG. 4 is a cross-sectional view of the effective area 23 of FIG. 3A taken along line A-A. The effective area 23 includes a metal plate 30 and a plurality of through holes 40 provided in the metal plate 30. As shown in FIG. 4, the metal plate 30 includes a first surface 31 and a second surface 32 located on the opposite side of the first surface 31. The first surface 31 of the metal plate 30 constitutes the first surface 201 of the deposition mask 20, and the second surface 32 of the metal plate 30 constitutes the second surface 202 of the deposition mask 20. The through hole 40 penetrates from the first surface 31 to the second surface 32 of the metal plate 30. The through hole 40 has a wall surface 41 extending from the first surface 31 to the second surface 32.

For example, an iron alloy containing nickel can be used as a material for forming the metal plate 30. The iron alloy may further contain cobalt in addition to nickel. For example, an iron alloy containing nickel and cobalt in total of 30% by mass or more and 54% by mass or less and a cobalt content of 0% by mass or more and 6% by mass or less can be used as a material for the metal plate 30. Specific examples of iron alloys containing nickel or nickel and cobalt include Invar material containing 34% by mass or more and 38% by mass or less of nickel, Super Invar material containing 30% by mass or more and 34% by mass or less of nickel and further containing cobalt, and low thermal expansion Fe-Ni-based plating alloy containing 38% by mass or more and 54% by mass or less of nickel. By using such an iron alloy, the thermal expansion coefficient of the metal plate 30 can be reduced. For example, when a glass substrate is used as the substrate 91, the thermal expansion coefficient of the metal plate 30 can be reduced to a low value equivalent to that of the glass substrate. This makes it possible to prevent the dimensional accuracy and positional accuracy of the deposition layer formed on the substrate 91 from decreasing during the deposition process due to the difference in thermal expansion coefficient between the deposition mask 20 including the metal plate 30 and the substrate 91.

The shape of the through hole 40 is determined by the metal plate 30 around the through hole 40. For example, the side surface of the shielding portion 35 constitutes the wall surface 41 of the through hole 40. The metal plate 30 around the through hole 40 functions to prevent the deposition material 82 from adhering to the display area of the substrate 91. In the following description, the metal plate 30 around the through hole 40 is also referred to as the shielding portion 35.

When the metal plate 30 constituting the deposition mask 20 is viewed along a normal direction to a plane direction D1 of a first surface 31 of the metal plate 30, i.e., along a thickness direction D2 of the metal plate 30, at least some of the through holes 40 are arranged at a predetermined first pitch C1 and a predetermined second pitch C2 along a first direction D11 and a second direction D12 that intersect with each other. Both the first direction D11 and the second direction D12 are directions in the plane direction D1. The smaller of the first pitch C1 and the second pitch C2 is determined, for example, as follows according to the pixel density of the display device or the projection device.
When the pixel density is 600 ppi or more: pitch is 42.3 μm or less When the pixel density is 1200 ppi or more: pitch is 21.2 μm or less When the pixel density is 3000 ppi or more: pitch is 8.5 μm or less A display device or projection device with a pixel density of 600 ppi is used, for example, as an organic EL display device for a smartphone.
A display device or projection device with a pixel density of 1200 ppi is used, for example, to display or project images or videos for expressing virtual reality.
A display device or projection device with a pixel density of 3000 ppi is used, for example, to display or project images or videos for expressing augmented reality.

The arrangement of the effective areas 23 is arbitrary. For example, the effective areas 23 may be arranged in a parallel arrangement as shown in FIG. 3A, or in a staggered arrangement as shown in FIG. 3B.

3A and 3B, when the metal plate 30 is viewed along the thickness direction D2 of the metal plate 30, the through hole 40 has a substantially rectangular contour with curved corners. The shape of the contour can be determined arbitrarily according to the shape of the pixel. For example, the contour may have another polygonal shape such as a hexagon or an octagon, or may have a circular shape. The contour shape may also be a combination of multiple shapes. The multiple through holes 40 may each have a different contour shape. When the through hole 40 has a polygonal contour, the opening dimension of the through hole 40 is the distance between a pair of opposing sides of the polygon, as shown in FIG. 3A.

As shown in FIG. 4, the surrounding region 24 is also formed of the same metal plate 30 as the effective region 23. The thickness H0 of the metal plate 30 in the surrounding region 24 may be greater than the thickness H1 of the metal plate 30 in the effective region 23. Similarly, the ear portion 21 described above may also be formed of the same metal plate 30 as the effective region 23, and the thickness of the ear portion 21 may be greater than the thickness H1 of the effective region 23. Although not shown, the thickness H0 of the surrounding region 24 and the thickness of the ear portion 21 may be the same as the thickness H1 of the effective region 23, or may be smaller than the thickness H1 of the effective region 23.

As described below, the effective area 23 is formed by first performing a first etching process on the metal plate 30 from the first surface 31 side, and then performing a second etching process on the metal plate 30 from the second surface 32 side. Therefore, the thickness H1 of the metal plate 30 in the effective area 23 is the thickness of the metal plate 30 after the second etching process.

The thickness H1 of the metal plate 30 constituting the shielding portion 35 is preferably 10 μm or less. The thickness H1 of the metal plate 30 constituting the shielding portion 35 may be 7 μm or less, 5 μm or less, 4 μm or less, 3 μm or less, or 2 μm or less. By making the thickness H1 of the metal plate 30 constituting the shielding portion 35 10 μm or less, it is possible to suppress the deposition material 82 from adhering to the wall surface 41 of the through hole 40 in the deposition process. This makes it possible to reduce the ratio of the deposition material 82 that cannot pass through the through hole 40, and to increase the utilization efficiency of the deposition material 82. On the other hand, if the thickness H1 of the metal plate 30 constituting the shielding portion 35 becomes too small, the deposition mask 20 is likely to be deformed or damaged when the deposition mask 20 is used or transported. In consideration of this point, the thickness H1 of the metal plate 30 constituting the shielding portion 35 is preferably 0.5 μm or more. The thickness H1 of the metal plate 30 may be 1.0 μm or more, or 1.5 μm or more.

The range of the thickness H1 of the metal plate 30 constituting the shielding part 35 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. For example, the range of the thickness H1 of the metal plate 30 constituting the shielding part 35 may be 0.5 μm or more and 10 μm or less, 1.0 μm or more and 5 μm or less, or 1.5 μm or more and 2 μm or less. The range of the thickness H1 of the metal plate 30 constituting the shielding part 35 may be determined by a combination of any two of the above-mentioned multiple upper limit candidate values. For example, the range of the thickness H1 of the metal plate 30 constituting the shielding part 35 may be 2 μm or more and 10 μm or less. The range of the thickness H1 of the metal plate 30 constituting the shielding part 35 may be determined by a combination of any two of the above-mentioned multiple lower limit candidate values. For example, the range of the thickness H1 of the metal plate 30 constituting the shielding part 35 may be 0.5 μm or more and 1.5 μm or less.

The through hole 40 and the shielding portion 35 that defines the through hole 40 will be described in detail with reference to Figures 5 and 6. Figure 5 is a cross-sectional view showing an enlarged view of the through hole 40 and the shielding portion 35. Figure 6 is a plan view showing an enlarged view of the through hole 40.

As shown in FIG. 5, the wall surface 41 of the through hole 40 includes a first end 411, a second end 412, and a minimum opening diameter portion 46. The first end 411 is the end of the wall surface 41 on the first surface 31 of the metal plate 30, and the second end 412 is the end of the wall surface 41 on the second surface 32 of the metal plate 30. The minimum opening diameter portion 46 is located between the first end 411 and the second end 412 of the wall surface 41, and is the portion having the smallest opening dimension.

In the example shown in FIG. 5, the wall surface 41 includes a first wall surface 43 extending from the first end 411 to the second end 412, a second wall surface 44 extending from the second end 412 to the first end 411, and a protruding end 45 where the first wall surface 43 and the second wall surface 44 join. The protruding end 45 is the innermost part of the wall surface 41 in the cross-sectional view of the through hole 40 and the shielding part 35. The inner side is the side approaching the central axis C of the through hole 40 in the cross-sectional view of the through hole 40 and the shielding part 35. The central axis C is a straight line passing through the midpoint between the opposing first ends 411 and the midpoint between the opposing second ends 412 in the cross-sectional view of the through hole 40. The outer side, which will be described later, is the side away from the central axis C of the through hole 40 in the cross-sectional view of the through hole 40 and the shielding part 35. The minimum opening diameter part 46 described above includes the protruding end 45.

As shown in FIG. 5, the first wall surface 43 may be expanded inward from the first end 411 toward the second end 412. The second wall surface 44 may be expanded inward from the second end 412 toward the first end 411. The states "expanding inward from the first end 411 toward the second end 412" and "the second wall surface 44 expands inward from the second end 412 toward the first end 411" only need to hold when minute irregularities with a depth or height of 200 nm or less present on the wall surface 41 are ignored.

5 and 6, the symbol S1 represents the opening dimension of the through hole 40 at the minimum opening diameter portion 46 (hereinafter also referred to as the minimum opening dimension), the symbol S2 represents the opening dimension of the through hole 40 at the first surface 31 (hereinafter also referred to as the first surface opening dimension), and the symbol S3 represents the opening dimension of the through hole 40 at the second surface 32 (hereinafter also referred to as the second surface opening dimension). The symbol S4 represents the width of the shielding portion 35 in the direction in which the multiple through holes 40 are arranged. The first surface opening dimension S2 is equal to or larger than the minimum opening dimension S1, and the second surface opening dimension S3 is equal to or larger than the first surface opening dimension S2. It is preferable that the difference between the first surface opening dimension S2 and the minimum opening dimension S1 is small. The value obtained by subtracting the minimum opening dimension S1 from the first surface opening dimension S2 is, for example, 0 μm or more and 2.0 μm or less. It is also preferable that the second surface opening dimension S3 is larger than the first surface opening dimension S2. For example, the second surface opening dimension S3 is preferably at least 0.5 μm or more larger than the first surface opening dimension S2. The second surface opening dimension S3 may be 1 μm or more larger than the first surface opening dimension S2, 1.5 μm or more larger, or 2 μm or more larger. The value obtained by subtracting the first surface opening dimension S2 from the second surface opening dimension S3 is preferably 10 μm or less. The value obtained by subtracting the first surface opening dimension S2 from the second surface opening dimension S3 may be 8 μm or less, 6 μm or less, or 4 μm or less. As shown in FIG. 6, when the through hole 40 is viewed along the thickness direction of the metal plate 30, the outline of the first end 411 may surround the outline of the minimum opening diameter portion 46, and the outline of the second end 412 may surround the outline of the first end 411.

The range of the value obtained by subtracting the first surface opening dimension S2 from the second surface opening dimension S3 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. For example, the value obtained by subtracting the first surface opening dimension S2 from the second surface opening dimension S3 may be 0.5 μm or more and 10 μm or less, 1 μm or more and 8 μm or less, 1.5 μm or more and 6 μm or less, or 2 μm or more and 4 μm or less. The range of the value obtained by subtracting the first surface opening dimension S2 from the second surface opening dimension S3 may be determined by a combination of any two of the above-mentioned multiple upper limit candidate values. For example, the value obtained by subtracting the first surface opening dimension S2 from the second surface opening dimension S3 may be 4 μm or more and 10 μm or less. The range of the value obtained by subtracting the first surface opening dimension S2 from the second surface opening dimension S3 may be determined by a combination of any two of the above-mentioned multiple lower limit candidate values. For example, the value obtained by subtracting the first surface opening dimension S2 from the second surface opening dimension S3 may be 0.5 μm or more and 2 μm or less.

The minimum opening dimension S1, the first surface opening dimension S2, the second surface opening dimension S3 and the width S4 are determined according to the pixel density of the display device or the projection device, for example, as shown in Table 1 below.

The minimum opening dimension S1, the first surface opening dimension S2, the second surface opening dimension S3, and the width S4 may be determined as a ratio to the thickness H1 of the metal plate 30 in the effective area 23. For example, the ratio of the minimum opening dimension S1 to the thickness H1 (= S1/H1) is, for example, 0.3 or more, may be 0.5 or more, may be 0.7 or more, or may be 1.0 or more. In addition, S1/H1 is, for example, 30 or less, may be 25 or less, may be 20 or less, or may be 15 or less.

The range of S1/H1 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. For example, S1/H1 may be 0.3 to 30, 0.5 to 25, 0.7 to 20, or 1.0 to 15. The range of S1/H1 may also be determined by a combination of any two of the above-mentioned multiple upper limit candidate values. For example, S1/H1 may be 15 to 30. The range of S1/H1 may also be determined by a combination of any two of the above-mentioned multiple lower limit candidate values. For example, S1/H1 may be 0.3 to 1.0.

In FIG. 5, the symbol L1 represents a virtual straight line passing through the minimum opening diameter portion 46 and the second end 412 in the cross-sectional view of the through hole 40. The symbol θ1 represents the angle between the direction in which the straight line L1 extends and the surface direction of the first surface 31 of the metal plate 30. The angle θ1 is preferably 80° or less. The angle θ1 may be 70° or less, 60° or less, 50° or less, 45° or less, or 40° or less. The angle θ1 is preferably 10° or more. The angle θ1 may be 15° or more, 20° or more, 25° or more, or 30° or more.

The range of the angle θ1 may be determined by a combination of any one of the multiple upper limit candidate values and any one of the multiple lower limit candidate values. For example, the angle θ1 may be 10° or more and 80° or less, 15° or more and 70° or less, 20° or more and 60° or less, 25° or more and 50° or less, or 30° or more and 45° or less. The range of the angle θ1 may also be determined by a combination of any two of the multiple upper limit candidate values. For example, the angle θ1 may be 40° or more and 80° or less. The range of the angle θ1 may also be determined by a combination of any two of the multiple lower limit candidate values. For example, the angle θ1 may be 10° or more and 30° or less.

The technical meaning of the angle θ1 will be explained below. In the deposition process using the deposition mask 20, the deposition material 82 may include a component that flies from the deposition source 81 toward the substrate 91 along the thickness direction of the metal plate 30, as well as a component that flies along a direction inclined relative to the thickness direction of the metal plate 30. A part of the deposition material 82 that flies along the inclined direction reaches and adheres to the second surface 32 of the metal plate 30 or the wall surface 41 of the through hole 40 before reaching the substrate 91. For this reason, the thickness of the deposition layer formed on the substrate 91 tends to be thinner the closer it is to the wall surface 41 of the through hole 40. Such a phenomenon in which the adhesion of the deposition material 82 to the substrate 91 is hindered by the wall surface 41 of the through hole 40 is also called a shadow. According to this embodiment, the occurrence of a shadow can be suppressed by configuring the wall surface 41 of the through hole 40 so that the above-mentioned angle θ1 is 80° or less.

However, reducing the angle θ1 leads to an increase in the distance S5 (see FIG. 5) between the minimum opening diameter portion 46 and the second end 412 in the planar direction of the first surface 31 of the metal plate 30. The increase in the distance S5 leads to an increase in the width S4 of the shielding portion 35. The pitch of the through holes 40 described above is equal to the sum of the minimum opening dimension S1 and the width S4 of the shielding portion 35. Therefore, when the distance S5 is increased, the reduction in the pitch of the through holes 40 is restricted.

As described above, in this embodiment, the thickness H1 of the metal plate 30 in the effective area 23 is small, for example, 10 μm or less. Therefore, the distance S5 required to reduce the angle θ1 is shorter than in the case of a conventional deposition mask having a thickness of, for example, more than 10 μm. Therefore, according to this embodiment, the angle θ1 can be set to 80° or less while maintaining a small pitch of the through holes 40.

Next, the shapes of the through hole 40 and the shielding portion 35 will be described in more detail with reference to FIG. 7. FIG. 7 is an enlarged cross-sectional view showing the shielding portion 35 that defines the through hole 40.

7, the symbol H2 represents the distance between the minimum opening diameter portion 46 and the first end 411 in the thickness direction D2 of the metal plate 30. In the following description, the distance H2 is also referred to as the height of the first wall surface 43. The height H2 of the first wall surface 43 is preferably 2.0 μm or less. The height H2 of the first wall surface 43 may be 1.5 μm or less, 1.0 μm or less, 0.8 μm or less, or 0.6 μm or less. By setting the height H2 of the first wall surface 43 to 1.0 μm or less, it is possible to suppress the variation in the position of the end of the deposition layer 92 formed on the substrate 91 by the deposition process in the surface direction of the substrate 91. This makes it possible to reduce the margin provided for the interval between two adjacent pixels.

On the other hand, in the manufacturing process of the deposition mask 20, if the design value of the height H2 of the first wall surface 43 is made too small, it is possible that the etching performed from the second surface 32 side will reach the first surface 31 side. If the etching performed from the second surface 32 side reaches the first surface 31 side, the variation in the minimum opening dimension S1 and the first surface opening dimension S2 will become large. In consideration of this point, the height H2 of the first wall surface 43 is preferably 0.1 μm or more. The height H2 of the first wall surface 43 may be 0.2 μm or more, or may be 0.3 μm or more.

The range of the height H2 of the first wall surface 43 may be determined by a combination of any one of a plurality of upper limit candidate values and any one of a plurality of lower limit candidate values. For example, the height H2 of the first wall surface 43 may be 0.1 μm or more and 2.0 μm or less, 0.2 μm or more and 1.5 μm or less, or 0.3 μm or more and 1.0 μm or less. The range of the height H2 of the first wall surface 43 may be determined by a combination of any two of a plurality of upper limit candidate values. For example, the height H2 of the first wall surface 43 may be 0.6 μm or more and 2.0 μm or less. The range of the height H2 of the first wall surface 43 may be determined by a combination of any two of a plurality of lower limit candidate values. For example, the height H2 of the first wall surface 43 may be 0.1 μm or more and 0.3 μm or less.

The preferred range of the height H2 of the first wall surface 43 may be determined as a relative value to the thickness H1 of the metal plate 30 constituting the shielding portion 35. For example, the ratio of the height H2 to the thickness H1 of the metal plate 30 constituting the shielding portion 35 (H2/H1) is preferably 0.4 or less. H2/H1 may be 0.35 or less, or 0.3 or less. Moreover, H2/H1 is preferably 0.1 or more. H2/H1 may be 0.15 or more, or 0.2 or more.

The range of H2/H1 may also be determined by a combination of any one of multiple upper limit candidate values and any one of multiple lower limit candidate values. For example, H2/H1 may be 0.1 or more and 0.4 or less, 0.15 or more and 0.35 or less, or 0.2 or more and 0.3 or less. The range of H2/H1 may also be determined by a combination of any two of multiple upper limit candidate values. For example, H2/H1 may be 0.3 or more and 0.4 or less. The range of H2/H1 may also be determined by a combination of any two of multiple lower limit candidate values. For example, H2/H1 may be 0.1 or more and 0.2 or less.

In FIG. 7, the symbol H3 represents the distance between the minimum opening diameter portion 46 and the second end 412 in the thickness direction D2 of the metal plate 30. In the following description, the distance H3 is also referred to as the height of the second wall surface 44. The height H3 of the second wall surface 44 is preferably 4 μm or less. The height H3 of the second wall surface 44 may be 3.5 μm or less, or may be 3 μm or less. Moreover, the height H3 of the second wall surface 44 is preferably 1 μm or more. The height H3 of the second wall surface 44 may be 1.5 μm or more, or may be 2 μm or more.

The range of the height H3 of the second wall surface 44 may be determined by a combination of any one of a plurality of upper limit candidate values and any one of a plurality of lower limit candidate values. For example, the height H3 of the second wall surface 44 may be 1 μm or more and 4 μm or less, 1.5 μm or more and 3.5 μm or less, or 2 μm or more and 3 μm or less. The range of the height H3 of the second wall surface 44 may be determined by a combination of any two of a plurality of upper limit candidate values. For example, the height H3 of the second wall surface 44 may be 3 μm or more and 4 μm or less. The range of the height H3 of the second wall surface 44 may be determined by a combination of any two of a plurality of lower limit candidate values. For example, the height H3 of the second wall surface 44 may be 1 μm or more and 2 μm or less.

As described later, the second surface 32 of the shielding portion 35 located between the two through holes 40 is formed by etching the entire portion of the metal plate 30 corresponding to the effective area 23 from the second surface 32 side of the metal plate 30. Therefore, the second surface 32 of the shielding portion 35 located between the two through holes 40 is flat. "The second surface is flat" means that the maximum distance H4 between the valley portion and the peak portion appearing on the second surface 32 is 1 μm or less within a range of a distance S6 centered on the center point in the surface direction D1 of the first surface 31 of the metal plate 30 in the cross-sectional view of the shielding portion 35, as shown in FIG. 7. The distance S6 is 1/2 of the width S4 of the shielding portion 35. H4 may be 0.8 μm or less, or may be 0.6 μm or less.

In addition, since the first surface 31 of the shielding portion 35 is not etched in the manufacturing process of the deposition mask 20, the maximum distance H4 between the valleys and peaks appearing on the second surface 32 is larger than the maximum distance between the valleys and peaks appearing on the first surface 31. H4 is, for example, 0.05 μm or more, may be 0.07 μm or more, or may be 0.1 μm or more.

The range of the maximum distance H4 between the valleys and peaks appearing on the second surface 32 may be determined by a combination of any one of a plurality of upper limit candidate values and any one of a plurality of lower limit candidate values. For example, H4 may be 0.05 μm or more and 1 μm or less, 0.07 μm or more and 0.8 μm or less, or 0.1 μm or more and 0.6 μm or less. H4 may also be determined by a combination of any two of a plurality of upper limit candidate values. For example, H4 may be 0.6 μm or more and 1 μm or less. H4 may also be determined by a combination of any two of a plurality of lower limit candidate values. For example, H4 may be 0.05 μm or more and 0.1 μm or less.

As described later, the second wall surface 44 of the wall surface 41 of the through hole 40 is a surface formed by side etching of the metal plate 30 with an etching solution that has penetrated between the metal plate 30 and the filler 52 filled on the first surface 31 side of the metal plate 30. In this case, as shown in FIG. 7, the cross-sectional shape of the second end 412 of the wall surface 41 is curved. Since the cross-sectional shape of the second end 412 is curved, the deposition material 82 flying along a direction inclined with respect to the thickness direction of the metal plate 30 is less likely to adhere to the second end 412 and the periphery of the second end 412. In addition, in the process of cleaning the deposition mask 20, foreign matter is less likely to become entangled in the second end 412 than when the second end 412 is sharp. The foreign matter is, for example, cellulose.

A protective film or the like may be applied to the second surface 32 of the metal plate 30 of the deposition mask 20 when the deposition mask 20 is transported, and the protective film may then be peeled off. In this case, since the cross-sectional shape of the second end 412 is curved, it is easier to peel off the protective film than if the second end 412 were sharp. For example, it is possible to prevent the protective film from getting caught on the second end 412, or the adhesive of the protective film from adhering to the second end 412 and remaining as a foreign object.

The radius of curvature R1 of the cross-sectional shape of the second end 412 is preferably 0.3 μm or more. The radius of curvature R1 may be 0.5 μm or more, or 1.0 μm or more. This allows the second end 412 to more significantly achieve the above-mentioned effects. In addition, the radius of curvature R1 of the cross-sectional shape of the second end 412 is preferably 2.0 μm or less. The radius of curvature R1 may be 1.5 μm or less, or 1.0 μm or less.

The range of the radius of curvature R1 may be determined by a combination of any one of the multiple upper limit candidate values and any one of the multiple lower limit candidate values, as in the case of the thickness H1 described above. For example, the radius of curvature R1 of the cross-sectional shape of the second end 412 may be 0.3 μm or more and 2.0 μm or less, or 0.5 μm or more and 1.5 μm or less. The range of the radius of curvature R1 may be determined by a combination of any two of the multiple upper limit candidate values. For example, the radius of curvature R1 of the cross-sectional shape of the second end 412 may be 1.0 μm or more and 2.0 μm or less. The range of the radius of curvature R1 may be determined by a combination of any two of the multiple lower limit candidate values. For example, the radius of curvature R1 of the cross-sectional shape of the second end 412 may be 0.3 μm or more and 1.0 μm or less.

Next, a method for identifying the second end 412 will be described with reference to FIG. 8. FIG. 8 is a further enlarged view of the shielding portion 35 that defines the through hole 40. The second end 412 may be defined as a portion that includes an angle change point where the amount of change in the direction in which the second wall surface 44 expands is 30° or more. The angle change point will be described below.

8, symbol P1 represents a point located on the second wall surface 44 in the cross-sectional view of the effective area 23. Symbol P2 represents a point displaced 500 nm from point P1 along the second wall surface 44 toward the second surface 32. Symbol Q1 represents a straight line tangent to the second wall surface 44 at point P1, and symbol Q2 represents a straight line tangent to the second wall surface 44 at point P2. Symbol δ represents the angle between the direction in which straight line Q1 extends and the direction in which straight line Q2 extends. The angle δ calculated in this manner is the amount of change in the angle of the second wall surface 44 at point P1. The second end 412 includes an angle change point where the amount of change in the angle calculated in this manner is 30° or more.

In the example shown in FIG. 8, the change in angle is 30° or more not only at point P1 but also at points between points Px and Py in FIG. 8. In this case, the second end 412 is defined as the center point of the range of the second wall surface 44 where the change in angle is 30° or more.

Manufacturing Method of the Deposition Mask Next, a method of manufacturing the deposition mask 20 by processing the metal plate 30 will be described mainly with reference to FIGS.

First, prepare the metal plate 30. The metal plate 30 may be a continuously extending metal plate 30 unwound from a roll. In this case, the manufacturing process of the deposition mask 20 may be performed on the metal plate 30 transported along a guide roller. Alternatively, the metal plate 30 may be a single metal plate 30 having dimensions corresponding to an exposure device or other device used in the manufacturing process of the deposition mask 20.

The thickness H0 of the metal plate 30 is preferably 15 μm or more. The thickness H0 of the metal plate 30 may be 20 μm or more, or may be 30 μm or more. By making the thickness H0 of the metal plate 30 10 μm or more, it is possible to prevent the metal plate 30 from being damaged due to the load applied to the metal plate 30 during the manufacturing process of the deposition mask 20. In addition, the thickness H0 of the metal plate 30 is preferably 200 μm or less. The thickness H0 may be 100 μm or less, or may be 50 μm or less.

The range of the thickness H0 of the metal plate 30 may be determined by a combination of any one of the multiple upper limit candidate values and any one of the multiple lower limit candidate values. For example, the thickness H0 of the metal plate 30 may be 10 μm or more and 200 μm or less, 15 μm or more and 100 μm or less, or 20 μm or more and 50 μm or less. The range of the thickness H0 may be determined by a combination of any two of the multiple upper limit candidate values. For example, the thickness H0 of the metal plate 30 may be 50 μm or more and 200 μm or less. The range of the thickness H0 may be determined by a combination of any two of the multiple lower limit candidate values. For example, the thickness H0 of the metal plate 30 may be 10 μm or more and 20 μm or less.

Next, as shown in FIG. 9, a first resist layer 51 is formed on the first surface 31 of the metal plate 30. The first resist layer 51 may be a layer formed by applying a solution containing a resist material to the first surface 31 and solidifying it. Alternatively, the first resist layer 51 may be a layer formed by attaching a film such as a dry film to the first surface 31. In order to reduce the thickness of the first resist layer 51, it is preferable to use a so-called coating type resist layer, in which a solution containing a resist material is applied and solidified.

When the coating type is used, the first resist layer 51 can be formed, for example, by coating the first surface 31 with a solution containing a photo-dissolving type, or so-called positive type, photosensitive material and solidifying it. At this time, a resist layer baking process may be performed to bake the first resist layer 51. The photosensitive material may be a photo-curing type, or so-called negative type.

An example of a positive photosensitive material is a novolac-based positive resist such as SC500. An example of a negative photosensitive material is a casein resist.

The resist layer baking temperature for baking the first resist layer 51 is set according to the photosensitive material. For example, when a novolac-based positive resist is used as the photosensitive material, the resist layer baking temperature is preferably 40°C or higher, may be 50°C or higher, or may be 60°C or higher. Also, when a novolac-based positive resist is used as the photosensitive material, the resist layer baking temperature is preferably 180°C or lower, may be 170°C or higher, or may be 160°C or lower.

When a novolac-based positive resist is used as the photosensitive material, the resist layer baking temperature may be determined by a combination of any one of a plurality of upper limit candidate values and any one of a plurality of lower limit candidate values. For example, the resist layer baking temperature may be 40°C or more and 180°C or less, 50°C or more and 170°C or less, or 60°C or more and 160°C or less. The range of the resist layer baking temperature may be determined by a combination of any two of a plurality of upper limit candidate values. For example, the resist layer baking temperature may be 160°C or more and 180°C or less. The range of the resist layer baking temperature may be determined by a combination of any two of a plurality of lower limit candidate values. For example, the resist layer baking temperature may be 40°C or more and 60°C or less.

When a casein resist is used as the photosensitive material, the resist layer baking temperature is preferably 80°C or higher, and may be 100°C or higher, or 120°C or higher. When a novolac-based positive resist is used as the photosensitive material, the resist layer baking temperature is preferably 250°C or lower, and may be 230°C or higher, or 200°C or lower.

When a casein resist is used as the photosensitive material, the resist layer baking temperature may be determined by a combination of any one of a plurality of upper limit candidate values and any one of a plurality of lower limit candidate values. For example, the resist layer baking temperature may be 80°C or more and 250°C or less, 100°C or more and 230°C or less, or 120°C or more and 200°C or less. The range of the resist layer baking temperature may be determined by a combination of any two of a plurality of upper limit candidate values. For example, the resist layer baking temperature may be 200°C or more and 250°C or less. The range of the resist layer baking temperature may be determined by a combination of any two of a plurality of lower limit candidate values. For example, the resist layer baking temperature may be 80°C or more and 120°C or less.

The thickness of the first resist layer 51 is preferably 5.0 μm or less. The thickness of the first resist layer 51 may be 3.0 μm or less, or may be 2.0 μm or less. By making the thickness of the first resist layer 51 5.0 μm or less, it is possible to suppress variation in the first surface opening dimension S2 among the multiple through holes 40. In addition, the thickness of the first resist layer 51 is preferably 1.0 μm or more. The thickness of the first resist layer 51 may be 1.5 μm or more, or may be 2.0 μm or more.

The range of thickness of the first resist layer 51 may be determined by a combination of any one of the multiple upper limit candidate values and any one of the multiple lower limit candidate values, as in the case of the thickness H1 described above. For example, the thickness of the first resist layer 51 may be 1.0 μm or more and 5.0 μm or less, or 1.5 μm or more and 3.0 μm or less. The range of thickness of the first resist layer 51 may also be determined by a combination of any two of the multiple upper limit candidate values. For example, the thickness of the first resist layer 51 may be 2.0 μm or more and 5.0 μm or less. The range of thickness of the first resist layer 51 may also be determined by a combination of any two of the multiple lower limit candidate values. For example, the thickness of the first resist layer 51 may be 1.0 μm or more and 2.0 μm or less.

As shown in FIG. 9, a second resist layer 56 may be formed on the second surface 32 of the metal plate 30. The photosensitive material contained in the second resist layer 56 may be the same as or different from the photosensitive material contained in the first resist layer 51. Although not shown, the second resist layer 56 may not be provided on the second surface 32 of the metal plate 30.

Next, an exposure process is performed to expose the first resist layer 51, and then a development process is performed to develop the first resist layer 51. As a result, as shown in FIG. 10, the first resist layer 51 is partially removed, and a plurality of exposed areas 53 that are not covered by the first resist layer 51 can be provided in the portion of the first surface 31 of the metal plate 30 that corresponds to the effective area 23.

When the second resist layer 56 is formed on the second surface 32 of the metal plate 30, the second resist layer 56 may be exposed and developed as shown in FIG. 10. In this embodiment, the second resist layer 56 is removed from the portion of the second surface 32 corresponding to the effective area 23, and the second resist layer 56 is exposed and developed so that the second resist layer 56 remains in the portion corresponding to the peripheral area 24 and the ear portion 21. Although not shown, the second resist layer 56 may be removed from the portion of the second surface 32 corresponding to the effective area 23 and the peripheral area 24, and the second resist layer 56 may be exposed and developed so that the second resist layer 56 remains in the portion corresponding to the ear portion 21.

Although not shown, a small amount of the second resist layer 56 may remain on the portion of the second surface 32 corresponding to the effective area 23, so long as the uniformity of the etching of the second surface 32 is not hindered. For example, a continuous exposed area of the portion of the second surface 32 corresponding to the effective area 23 where the second resist layer 56 is not provided may have a dimension of 0.5 μm or more in at least one surface direction of the second surface 32.

Then, a first etching process is carried out in which the metal plate 30 is etched from the first surface 31 side using the first resist layer 51 as a mask. This allows a first recess 50 to be formed in the first surface 31 as shown in FIG. 11. The first recess 50 has, for example, a hemispherical shape.

Next, as shown in FIG. 12, a filling step is performed to fill the first recess 50 with a filler 52. For example, a solution containing the filler 52 is applied to the first surface 31 side of the metal plate 30. The filler 52 may be a thermoplastic resin, a photoresist, or the like. The photoresist is, for example, a positive resist containing a positive-type photosensitive material. As shown in FIG. 12, the filler 52 may cover the first resist layer 51. Specific examples of the resin constituting the filler 52 include an acrylic resin and a novolac resin.

Next, a filler firing process is carried out to fire the filler 52. Note that if a thermoplastic resin is used as the filler 52, the filler firing process does not need to be carried out.

In FIG. 12, the symbol H5 represents the distance from the first surface 31 to the top of the filler 52 in the thickness direction of the metal plate 30. The top is the part of the filler 52 that is farthest from the first surface 31 in the thickness direction of the metal plate 30. The distance H5 is equal to the depth of the first recess 50. The distance H5 is preferably 7.0 μm or less. The distance H5 may be 6.0 μm or less, or 5.0 μm or less. The distance H5 is preferably 1.0 μm or more. The distance H5 may be 2.0 μm or more, 3.0 μm or more, or 4.0 μm or more.

The range of the distance H5 may be determined by a combination of any one of the multiple upper limit candidate values and any one of the multiple lower limit candidate values. For example, the distance H5 may be 1.0 μm or more and 7.0 μm or less, 2.0 μm or more and 6.0 μm or less, or 3.0 μm or more and 5.0 μm or less. The range of the distance H5 may also be determined by a combination of any two of the multiple upper limit candidate values. For example, the distance H5 may be 6.0 μm or more and 7.0 μm or less. The range of the distance H5 may also be determined by a combination of any two of the multiple lower limit candidate values. For example, the distance H5 may be 1.0 μm or more and 4.0 μm or less.

The ratio of the distance H5 to the thickness H0 of the metal plate 30 before etching (=H5/H0) is preferably 0.1 or more. H5/H0 may be 0.3 or more, or may be 0.5 or more. By making H5/H0 0.1 or more, it is possible to suppress the variation in the time it takes for the etching on the second surface 32 side described below to reach the filler 52 depending on the position. Furthermore, H5/H0 is preferably 0.9 or less, and may be 0.7 or less, or may be 0.5 or less.

The range of H5/H0 may be determined by a combination of any one of multiple upper limit candidate values and any one of multiple lower limit candidate values. For example, H5/H0 may be 0.1 or more and 0.9 or less, or 0.3 or more and 0.7 or less. The range of H5/H0 may also be determined by a combination of any two of multiple upper limit candidate values. For example, H5/H0 may be 0.5 or more and 0.9 or less. The range of H5/H0 may also be determined by a combination of any two of multiple lower limit candidate values. For example, H5/H0 may be 0.1 or more and 0.5 or less.

Then, a second etching step is performed in which the metal plate 30 is etched from the second surface 32 side. The etching solution may be one containing ferric chloride solution and hydrochloric acid. The temperature of the etching solution is, for example, 25°C or higher, may be 30°C or higher, or may be 35°C or higher. The temperature of the etching solution is, for example, 80°C or lower, may be 70°C or lower, or may be 60°C or lower.

The temperature range of the etching liquid may be determined by a combination of any one of a plurality of upper limit candidate values and any one of a plurality of lower limit candidate values. For example, the temperature of the etching liquid may be 25°C or more and 80°C or less, 30°C or more and 70°C or less, or 35°C or more and 60°C or less. The temperature range of the etching liquid may also be determined by a combination of any two of a plurality of upper limit candidate values. For example, the temperature of the etching liquid may be 60°C or more and 80°C or less. The temperature range of the etching liquid may also be determined by a combination of any two of a plurality of lower limit candidate values. For example, the temperature of the etching liquid may be 25°C or more and 35°C or less.

The second etching process is continued until the second surface 32 of the metal plate 30 located in the effective area 23 is located at least closer to the first surface 31 than the top 521 of the filler 52, as shown in FIG. 13. By allowing the etching from the second surface 32 side to reach the top 521 of the filler 52, the through hole 40 can be formed in the deposition mask 20.

The second etching process is continued until the second surface opening dimension S3 of the through hole 40 becomes equal to or larger than the minimum opening dimension S1 at the tip 45. The second etching process is preferably continued until the second surface opening dimension S3 of the through hole 40 becomes 1 μm or more larger than the minimum opening dimension S1, and more preferably until the second surface opening dimension S3 of the through hole 40 becomes 2 μm or more larger than the minimum opening dimension S1. The second etching process may be continued until the second surface opening dimension S3 of the through hole 40 becomes larger than the first surface opening dimension S2. The second etching process is preferably continued until the second surface opening dimension S3 of the through hole 40 becomes 1 μm or more larger than the first surface opening dimension S2, and more preferably until the second surface opening dimension S3 of the through hole 40 becomes 2 μm or more larger than the first surface opening dimension S2.

Preferably, the second etching step is continued until the ratio (=H1/H5) of the thickness H1 of the metal plate 30 located in the effective area 23 to the distance H5 from the first surface 31 to the top 521 of the filler 52 becomes 0.9 or less, as shown in FIG. 14. This makes it easier for the etching solution to penetrate between the filler 52 and the metal plate 30. As a result, as shown in FIG. 14, the metal plate 30 around the filler 52 is side-etched, and a gap 57 is easily formed between the filler 52 and the metal plate 30. The surface formed on the metal plate 30 by the side etching constitutes the above-mentioned second wall surface 44 of the wall surface 41 of the through hole 40. By controlling the amount of side etching, the second wall surface 44 can have a shape that expands inward as it moves from the second end 412 toward the first end 411. H1/H5 may be 0.8 or less, 0.7 or less, or 0.6 or less. Furthermore, H1/H5 may be 0.1 or more, 0.2 or more, or 0.3 or more.

The range of H1/H5 may be determined by a combination of any one of the multiple upper limit candidate values and any one of the multiple lower limit candidate values, as in the case of the thickness H1 described above. For example, H1/H5 may be 0.1 or more and 0.9 or less, 0.2 or more and 0.8 or less, or 0.3 or more and 0.7 or less. The range of H1/H5 may also be determined by a combination of any two of the multiple upper limit candidate values. For example, H1/H5 may be 0.6 or more and 0.9 or less. The range of H1/H5 may also be determined by a combination of any two of the multiple lower limit candidate values. For example, H1/H5 may be 0.1 or more and 0.3 or less.

The time for which etching is continued in the second etching process can be determined, for example, based on etching condition data acquired in advance. The etching condition data includes, for example, the relationship between the time for which etching is continued and the thickness H1 of the effective area 23. The etching condition data may include the relationship between the time for which etching is continued and the height H2 of the first wall surface 43, and may include the relationship between the time for which etching is continued and the height H3 of the second wall surface 44. Based on these etching condition data, the time for which etching is continued in the second etching process can be determined so that the thickness H1, height H2, height H3, etc. become appropriate values.

Next, as shown in FIG. 15, a filler removal process is performed to remove the filler 52. This creates through holes 40 in the metal plate 30. A solution containing sodium hydroxide or the like can be used as a solution for removing the filler 52. A resist layer removal process is also performed to remove the first resist layer 51 and the second resist layer 56. A solution containing sodium hydroxide or the like can be used as a solution for removing the resist layer. In this way, a deposition mask 20 including a metal plate 30 having a plurality of through holes 40 can be obtained. The filler removal process and the resist layer removal process may be performed simultaneously by using a solution capable of removing both the filler and the resist layer.

In this embodiment, as described above, the etching of the second surface 32 in the portion of the metal plate 30 corresponding to the effective area 23 is performed without providing a resist layer on the second surface 32. In other words, a recess that extends across the multiple first recesses 50 formed on the first surface 31 is formed on the second surface 32. This makes it possible to suppress variation in the position of the minimum opening diameter portion 46 of the through holes 40 and the minimum opening dimension S1 among the multiple through holes 40.

Next, the effects of this embodiment will be further explained by comparing this embodiment with a comparative embodiment. Figures 16 and 17 are diagrams showing a method for manufacturing a deposition mask 20 in a comparative embodiment. In the comparative embodiment shown in Figures 16 and 17, parts that are the same as or have similar functions to those in the above-mentioned embodiment are given the same reference numerals and detailed explanations are omitted.

16 is a cross-sectional view showing the first resist layer 51 provided on the first surface 31 of the metal plate 30 and the second resist layer 56 provided on the second surface 32 in the comparative embodiment. As shown in FIG. 16, in the comparative embodiment, a plurality of exposed areas 58 that are not covered by the second resist layer 56 are provided in the portion of the second surface 32 of the metal plate 30 corresponding to the effective area 23. Thereafter, as in the case of the present embodiment, the metal plate 30 is etched from the first surface 31 side to form the first recess 50, and then the first recess 50 is filled with the filler 52. Thereafter, the metal plate 30 is etched from the second surface 32 side using the second resist layer 56 as a mask to form a plurality of second recesses 55 on the second surface 32. By the plurality of first recesses 50 and the plurality of second recesses 55 communicating with each other, a plurality of through holes 40 can be formed in the metal plate 30 as shown in FIG. 17.

However, in the comparative embodiment, due to an error in aligning the exposure mask, the relative position of the second resist layer 56 with respect to the first resist layer 51 may deviate from the design, as shown in the right part of FIG. 16. In this case, as shown in the right part of FIG. 17, the relative position of the second recess 55 with respect to the first recess 50 may deviate, and as a result, the position where the first recess 50 and the second recess 55 join in one through hole 40 may vary in the thickness direction of the metal plate 30. That is, as shown by the symbol H6 in FIG. 17, the position of the minimum opening diameter portion 46 of the through hole 40 may vary in the thickness direction of the metal plate 30. As a result, the height H2 of the first wall surface 43 varies.

In the comparative embodiment, etching from the second surface 32 of the metal plate 30 proceeds individually in the multiple second recesses 55. In this case, the etching speed in each second recess 55 may vary due to variations in the position of the top of the filler 52, variations in the concentration of the etching solution, variations in the flow of the etching solution, and the like. As a result, the position where the first recess 50 and the second recess 55 join varies, and the minimum value of the opening dimension of the through hole 40 tends to vary. Also, the height H2 of the first wall surface 43 varies.

In contrast, in this embodiment, the second resist layer 56 is not provided on at least most of the portion of the second surface 32 that corresponds to the effective area 23. Therefore, in the second etching step, the speed and concentration of the etching solution in the portion that corresponds to the effective area 23 are more likely to be uniform than in the comparative embodiment. Therefore, it is possible to suppress variation in the size and position of the minimum opening diameter portion 46 and the height H2 of the first wall surface 43 among the multiple through holes 40 in the effective area 23.

In addition, in this embodiment, the second resist layer 56 is not provided on at least most of the portion of the second surface 32 that corresponds to the effective area 23, so that errors in the size and position of the minimum opening diameter portion 46 due to errors in the position of the second resist layer 56 are unlikely to occur. In this respect, it is possible to suppress variations in the size and position of the minimum opening diameter portion 46 and the height H2 of the first wall surface 43 among the multiple through holes 40 in the effective area 23.

In addition, in this embodiment, since the variation in the etching speed and the like in the second etching process can be suppressed, it becomes easy to carry out the second etching process so that the height H2 of the first wall surface 43 is reduced while leaving the first wall surface 43. Therefore, the design value and the actual measured value of the height H2 of the first wall surface 43 can be reduced, for example, to 2.0 μm or less. This makes it possible to suppress the occurrence of shadows during the deposition process.

Manufacturing Method of the Deposition Mask Device Next, a welding step is performed to weld the deposition mask 20 obtained as described above to the frame 15. In this way, the deposition mask device 10 including the deposition mask 20 and the frame 15 can be obtained.

Vapor Deposition Method Next, a method of attaching a vapor deposition material 82 to a substrate 91 using the vapor deposition mask 20 according to this embodiment and forming a vapor deposition layer 92 on the substrate 91 as shown in Fig. 18 will be described. In the following description, an article including at least the substrate 91 and the vapor deposition layer 92 formed on the substrate 91 by a vapor deposition process is also referred to as a vapor deposition substrate 90. The vapor deposition substrate 90 is used in an organic EL display device or the like.

In the deposition process in which the deposition material 82 is applied to the substrate 91 using the deposition mask 20, the deposition mask device 10 is first positioned so that the deposition mask 20 faces the substrate 91. The deposition mask 20 is then brought into close contact with the substrate 91 using a magnet 85. The inside of the deposition device 80 is then placed in a vacuum atmosphere. In this state, the deposition material 82 is evaporated and caused to fly toward the substrate 91, so that the deposition material 82 can be applied to the substrate 91 in a pattern corresponding to the through-holes 40 of the deposition mask 20.

22 is an enlarged cross-sectional view of the deposition layer 92 formed on the substrate 91 by the deposition process. According to the above-mentioned method for manufacturing the deposition mask 20, the variation in the etching speed in the second etching process can be suppressed, so that the height H2 of the first wall surface 43 of the through hole 40 can be set small. Therefore, the width K1 of the first wall surface 43 in the surface direction of the first surface 31 of the metal plate 30 can be reduced. As a result, as shown in FIG. 22, the width K1 of the portion of the deposition layer 92 formed outside the minimum opening diameter portion 46 of the through hole 40 of the deposition mask 20 can be suppressed from varying among multiple pixels. Therefore, the margin provided in the design of the deposition substrate 90 can be reduced in consideration of the interference between adjacent pixels.

In addition, according to the above-described manufacturing method of the deposition mask 20, it is possible to suppress variation in the size and position of the minimum opening diameter portion 46 among the multiple through holes 40. Therefore, when a deposition layer 92 is formed so as to overlap an electrode 93 on a substrate 91 as shown in FIG. 19, it is possible to suppress variation in the size and position of the deposition layer 92 relative to the size and position of the electrode 93. This can also contribute to reducing the margin to be considered in the design of the deposition substrate 90.

By reducing the margins considered in the design of the deposition substrate 90, the pixel density of the deposition substrate 90 can be increased. Furthermore, when the pixel density of the deposition substrate 90 is constant, by reducing the margins, the area of the electrode 93 can be enlarged while preventing interference between adjacent pixels. This makes it possible to increase the ratio of the area of the deposition layer 92 that overlaps with the electrode 93. This leads to an improvement in the luminous efficiency of the deposition layer 92 when the deposition layer 92 is a light-emitting layer. This makes it possible to increase the brightness of the deposition layer 92 and extend the life of the deposition layer 92.

Next, the embodiments of the present disclosure will be described in more detail with reference to examples. However, the embodiments of the present disclosure are not limited to the description of the following examples as long as they do not exceed the gist of the disclosure.

Example 1
First, a metal plate 30 was prepared, which was made of an iron alloy having a thickness of 30 μm and containing 34% by mass or more and 38% by mass or less of nickel. Next, a first resist layer 51 was formed on the first surface 31 of the metal plate 30, as shown in FIG. 10 described above. Specifically, first, a novolac-based positive resist SC500 was applied to the first surface 31 of the metal plate 30. Next, the positive resist was heated at 140° C. for 600 seconds to obtain a first resist layer 51. Then, the first resist layer 51 was exposed and developed to form an exposed region 53 shown in FIG. 10. Next, the metal plate 30 was etched from the first surface 31 side using the first resist layer 51 as a mask to form a first recess 50. The opening dimension S2 of the first recess 50 was 5.0 μm, the depth H5 of the first recess 50 was 2.3 μm, and the pitch of the first recess 50 was 8.0 μm.

Then, the first recess 50 was filled with the filler 52, and the filler 52 was fired. SC500 was used as the filler 52. The firing temperature and firing time of the filler 52 were 140°C and 600 seconds, respectively.

Next, in a state where no resist layer was provided on the second surface 32 of the metal plate 30, a second etching process was performed in which the metal plate 30 was etched from the second surface 32 side to form a through hole 40 in the metal plate 30. The etching solution used was one containing ferric chloride solution and hydrochloric acid. The temperature of the etching solution was 45°C. The etching time was determined based on the previously obtained etching condition data so that the second surface opening dimension S3 of the through hole 40 was 1 μm or more larger than the first surface opening dimension S2.

Then, the filler 52 and the first resist layer 51 were removed. FIG. 23 shows the result of observing the cross section of the through hole 40 of the deposition mask 20 obtained in this manner. A ZEISS ULTRA55 scanning electron microscope was used as the device for observing the cross section of the through hole 40. In the example shown in FIG. 23, minute irregularities with a depth or height of 100 nm or less were observed on the first wall surface 43 and the second wall surface 44 of the wall surface 41 of the through hole 40.

Example 2
The through hole 40 was formed in the same manner as in Example 1, except that the etching time in the second etching step was made longer than that in Example 1. Moreover, the cross section of the through hole 40 in the deposition mask 20 was observed in the same manner as in Example 1. The results are shown in FIG.

Example 3
The through hole 40 was formed in the same manner as in Example 1, except that the etching time in the second etching step was made longer than that in Example 2. Moreover, the cross section of the through hole 40 in the deposition mask 20 was observed in the same manner as in Example 1. The result is shown in FIG.

10 Deposition mask device 15 Frame 20 Deposition mask 201 First surface 202 Second surface 21 Ear portion 22 Middle portion 23 Effective area 24 Surrounding area 30 Metal plate 31 First surface 32 Second surface 35 Shielding portion 40 Through hole 41 Wall surface 411 First end 412 Second end 43 First wall surface 44 Second wall surface 45 Projection 46 Minimum opening diameter portion 50 First recess 51 First resist layer 52 Filler 53 Exposed area 55 Second recess 56 Second resist layer 57 Gap 58 Exposed area 80 Deposition device 81 Deposition source 82 Deposition material 83 Heater 85 Magnet 90 Deposition substrate 91 Substrate 92 Deposition layer 93 Electrode

Claims (1)

The metal plate includes a first surface, a second surface located opposite to the first surface, and a through hole, and has a thickness of 10 μm or less;
the through hole has a wall surface including a first end that is an end on the first surface and a second end that is an end on the second surface,
the wall surface is located between the first end and the second end in a thickness direction of the metal plate and includes a minimum opening diameter portion having a smallest opening diameter ,
a distance between the minimum opening diameter portion and the first end in a thickness direction of the metal plate is 2.0 μm or less;
The second end has a cross-sectional shape that is curved with a radius of curvature of 0.3 μm or more and 2.0 μm or less .