KR20230007527A - Metal plate, metal plate production method, and method for producing vapor deposition mask using metal plate - Google Patents

Abstract

It aims at providing a metal plate with a small elongation difference rate. The elongation difference rate at the central part in the width direction of the metal plate is 10×10 ^-5 or less. Moreover, the elongation difference rate at the edge part of the width direction of a metal plate is set to 20x10 ^-5 or less. Further, the difference in elongation at the end portion of the metal plate in the width direction is larger than the maximum value of the difference in elongation in the central portion in the width direction of the metal plate.

Description

A metal plate, a method for manufacturing a metal plate, and a method for manufacturing a deposition mask using a metal plate {METAL PLATE, METAL PLATE PRODUCTION METHOD, AND METHOD FOR PRODUCING VAPOR DEPOSITION MASK USING METAL PLATE}

The present invention relates to a metal plate used for manufacturing a deposition mask by forming a plurality of through holes. The present invention also relates to a method for manufacturing a metal plate. Further, the present invention relates to a method for manufacturing a deposition mask used for vapor deposition in a desired pattern using a metal plate.

In recent years, display devices used in portable devices such as smart phones and tablet PCs are required to have a high resolution, for example, a pixel density of 300 ppi or higher. Moreover, also in a portable device, the demand for a thing corresponding to full high-vision is growing, and in this case, it is requested|required that the pixel density of a display apparatus should be 450 ppi or more, for example.

Organic EL display devices are attracting attention because of their good responsiveness and low power consumption. As a method of forming pixels of an organic EL display device, a method of forming pixels in a desired pattern using a deposition mask including through holes arranged in a desired pattern is known. Specifically, first, a deposition mask is brought into close contact with a substrate for an organic EL display device, and then both the adhered deposition mask and the substrate are put into a deposition apparatus to deposit an organic material or the like. A deposition mask can generally be manufactured by forming a through hole in a metal plate by etching using a photolithography technique (for example, Patent Document 1). For example, first, a resist film is formed on a metal plate, then the resist film is exposed with an exposure mask in close contact with the resist film to form a resist pattern, and then the metal plate is etched using the resist pattern as a mask to form a through hole. is formed

(Patent Document 1) Japanese Unexamined Patent Publication No. 2004-39319

When a deposition material is deposited on a substrate using a deposition mask, the deposition material is adhered to not only the substrate but also the deposition mask. For example, some of the deposition materials are directed toward the substrate along a direction greatly inclined with respect to the normal direction of the deposition mask, but such deposition materials reach and adhere to the wall surface of the through hole of the deposition mask before reaching the substrate. . In this case, it is difficult for the evaporation material to adhere to a region of the substrate located near the wall surface of the through hole of the deposition mask. It is possible to think of a case where an undesirable part occurs. That is, it is conceivable that the deposition in the vicinity of the wall surface of the through hole of the deposition mask becomes unstable. Therefore, when a deposition mask is used to form the pixels of the organic EL display device, the dimensional accuracy and positional accuracy of the pixels are lowered, and as a result, the luminous efficiency of the organic EL display device is lowered.

In order to solve such a subject, it is conceivable to reduce the thickness of the metal plate used to manufacture the deposition mask. This is because by reducing the thickness of the metal plate, the height of the wall surface of the through hole of the deposition mask can be reduced, thereby reducing the ratio of deposition materials adhering to the wall surface of the through hole. However, in order to obtain a metal sheet having a small thickness, it is necessary to increase the rolling ratio at the time of rolling a base material to manufacture a metal sheet. Here, the rolling ratio is a value calculated by (thickness of base material-metal sheet)/(thickness of base material). Even when heat treatment such as annealing is performed after rolling, the degree of non-uniformity of deformation based on rolling usually increases as the rolling ratio increases. For example, it is known that the elongation rate of the metal sheet differs depending on the position in the width direction (direction orthogonal to the transport direction of the base material), and as a result, wavy shapes appear on the metal sheet. Specifically, a wavy shape at the end portion in the width direction, called ear development, and a wavy shape at the center portion in the width direction, called central elongation, are exemplified. If such a wavy pattern appears, the exposure mask cannot be sufficiently brought into close contact with the resist film on the metal plate, and as a result, the positional accuracy and dimensional accuracy of through holes formed in the metal plate may decrease. When the positional accuracy and dimensional accuracy of the through hole decrease, the dimensional accuracy and positional accuracy of the pixels of the organic EL display device obtained by using the deposition mask decrease.

In addition, in order to reduce the manufacturing cost of the deposition mask, first, a plurality of effective regions including a plurality of through holes corresponding to one organic EL display device are formed over the entire surface of the metal plate, and then It is known to cut a plurality of metal plates along , and thereby fabricate a plurality of elongated deposition masks at once. However, when the elongation rate of the metal plate differs depending on the position in the width direction, the lengths of a plurality of elongated vapor deposition masks obtained after cutting are different. In this case, the pitch of each through hole in the effective region of the deposition mask is different for each deposition mask, and as a result, the size and position of pixels of the organic EL display device obtained by using the deposition mask vary depending on the individual. can also be considered

An object of the present invention is to provide a metal plate, a method for manufacturing the metal plate, and a method for manufacturing a deposition mask that can effectively solve these problems.

A first aspect of the present invention is a method for manufacturing a metal plate used for manufacturing a deposition mask by forming a plurality of through holes, wherein the through holes of the deposition mask are formed by etching the metal plate, the method for manufacturing the metal plate , a rolling step of rolling a base material to obtain the metal plate, and a cutting step of cutting both ends of the metal plate in a width direction over a predetermined range, wherein the metal plate after the cutting step has a length in the longitudinal direction of that The width of the metal plate after the cutting step relative to the reference length, which at least partially has a wavy shape due to being different depending on the position in the width direction, and the minimum value of the length of the metal plate after the cutting step is referred to as a reference length. When the ratio of the difference in the length of the metal plate at each position in the direction is referred to as the elongation difference rate, the following conditions (1) to (3) are satisfied,

(1) The elongation difference rate at the central portion in the width direction of the metal sheet after the cutting step is 10×10 ^-5 or less;

(2) the elongation rate at the end of the metal sheet in the width direction after the cutting step is 20×10 ^-5 or less; and

(3) the elongation difference rate at the end portion is greater than the maximum value of the elongation difference rate at the central portion;

The said central part is a metal plate manufacturing method which is a part which occupies 40% of the width of the said metal plate, including the central part of the width direction of the said metal plate after the said cutting process.

The method for manufacturing a metal sheet according to the present invention may further include an annealing step of annealing the metal sheet obtained in the rolling step to remove internal stress of the metal sheet.

In the method for manufacturing a metal sheet according to the present invention, the annealing step may be performed while stretching the metal sheet in the longitudinal direction.

In the method for manufacturing a metal plate according to the present invention, the annealing step may be performed while the metal plate is wound around a core.

In the method for manufacturing a metal plate according to the present invention, preferably, the thermal expansion coefficient of the base material is equal to that of a substrate on which an evaporation material is formed through a deposition mask manufactured from the metal plate.

In the method for manufacturing a metal sheet according to the present invention, the base material may be made of an invar material.

A second aspect of the present invention is a metal plate used for manufacturing a deposition mask by forming a plurality of through holes. Partially, the minimum value of the length of the metal plate is referred to as a reference length, and the ratio of the difference between the length of the metal plate at each position in the width direction of the metal plate to the reference length is referred to as an elongation difference rate, The following conditions (1) to (3) are satisfied,

(1) the elongation rate at the central portion in the width direction of the metal plate is 10×10 ^-5 or less;

(2) the elongation rate at the end of the metal plate in the width direction is 20×10 ^-5 or less; and

(3) the elongation difference rate at the end portion is greater than the maximum value of the elongation difference rate at the central portion;

The central part is a metal plate that is a part that occupies 40% of the width of the metal plate, including the central part in the width direction of the metal plate.

The thermal expansion coefficient of the metal plate according to the present invention is preferably equal to the thermal expansion coefficient of the substrate on which the evaporation material is deposited through a deposition mask made from the metal plate.

The metal sheet according to the present invention may be composed of an invar material.

A third aspect of the present invention is a method for manufacturing a deposition mask having an effective region in which a plurality of through holes are formed, and a peripheral region located around the effective region, which is a metal plate, the length of which in the longitudinal direction is equal to that of the width direction of the deposition mask. A step of preparing a metal plate at least partially having a wavy shape attributable to a different position depending on the position, a resist pattern forming step of forming a resist pattern on the metal plate, etching the metal plate using the resist pattern as a mask, and an etching step of forming a concave portion for defining and forming the through hole in a region of the metal plate constituting the region, wherein a minimum value of the length of the metal plate is referred to as a reference length, and for the reference length, the metal plate When the ratio of the difference in the length of the metal plate at each position in the width direction is referred to as the elongation difference rate, the following conditions (1) to (3) are satisfied,

(1) the elongation rate at the central portion in the width direction of the metal plate is 10×10 ^-5 or less;

(2) the elongation rate at the end of the metal plate in the width direction is 20×10 ^-5 or less; and

(3) the elongation difference rate at the end portion is greater than the maximum value of the elongation difference rate at the central portion;

The method of manufacturing a deposition mask in which the central portion is a portion that occupies 40% of the width of the metal plate, including the central portion in the width direction of the metal plate.

In the method for manufacturing a deposition mask according to the present invention, the resist pattern forming step includes a step of forming a resist film on the metal plate, a step of vacuum-contacting an exposure mask to the resist film, and a step of forming the resist through the exposure mask. You may have a step of exposing the film to light in a predetermined pattern.

In the method for manufacturing a deposition mask according to the present invention, preferably, the thermal expansion coefficient of the metal plate is equivalent to that of a substrate on which an evaporation material is deposited via a deposition mask manufactured from the metal plate.

In the method for manufacturing a deposition mask according to the present invention, the metal plate may be made of an invar material.

According to the present invention, it is possible to obtain a deposition mask having a small degree of waviness and a small variation in the pitch of each through hole in the effective region. For this reason, the dimensional accuracy and positional accuracy of the evaporation material deposited on the substrate can be improved.

1 is a diagram for explaining an embodiment of the present invention, and is a schematic plan view showing an example of a deposition mask device including a deposition mask.
FIG. 2 is a diagram for explaining a method of depositing using the deposition mask device shown in FIG. 1;
FIG. 3 is a partial plan view illustrating the deposition mask shown in FIG. 1 .
4 is a cross-sectional view taken along line IV-IV of FIG. 3 .
5 is a cross-sectional view taken along line VV of FIG. 3 .
6 is a cross-sectional view taken along line VI-VI of FIG. 3 .
Fig. 7(a) is a diagram showing a step of rolling a base material to obtain a metal sheet having a desired thickness, and Fig. 7(b) is a diagram showing a step of annealing the metal sheet obtained by rolling.
Fig. 8 is a perspective view showing a metal plate obtained by the steps shown in Fig. 7 (a) and (b).
(a), (b), (c) and (d) of FIG. 9 are cross-sectional views taken along lines aa, bb, cc and dd of FIG. 8, respectively.
Fig. 10 is a diagram showing the elongation difference rate at each position in the width direction of the metal plate.
FIG. 11 is a schematic diagram for explaining an example of a manufacturing method of the deposition mask shown in FIG. 1 as a whole.
Fig. 12 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a cross-sectional view showing a step of forming a resist film on a metal plate.
Fig. 13 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a cross-sectional view showing a step of bringing an exposure mask into close contact with a resist film.
14 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a diagram showing an elongated metal plate in a cross section along a normal direction.
15 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a diagram showing an elongated metal plate in a cross section along a normal direction.
16 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a diagram showing an elongated metal plate in a cross section along a normal direction.
17 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a diagram showing an elongated metal plate in a cross section along a normal direction.
18 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a diagram showing an elongated metal plate in a cross section along a normal direction.
19 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a diagram showing an elongated metal plate in a cross section along a normal direction.
20 is a diagram for explaining an example of a method for manufacturing a deposition mask, and is a diagram showing an elongated metal plate in a cross section along a normal direction.
Fig. 21 is a plan view showing the first sample loaded on the surface plate.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of this invention is described with reference to drawings. In addition, in the drawings attached to this specification, for convenience of illustration and understanding, the scale and the dimension ratio of length and width are appropriately changed from those of the real thing and exaggerated.

1 to 20 are diagrams for explaining an embodiment according to the present invention. In the following embodiments and modifications thereof, a method for manufacturing a deposition mask used for patterning an organic material onto a substrate in a desired pattern when manufacturing an organic EL display device will be described as an example. However, it is not limited to these applications, and the present invention can be applied to methods of manufacturing deposition masks used for various purposes.

Also, in this specification, the terms "plate", "sheet", and "film" are not distinguished from each other based only on differences in names. For example, a "plate" is a concept that includes members that can be called sheets and films, and therefore, for example, a "metal plate" is only a difference between a member called a "metal sheet" or a "metal film" and a name. cannot be distinguished

Further, "plate surface (sheet surface, film surface)" refers to a target plate-like member (sheet-shaped member, film-shaped member) when the target plate-shaped (sheet-shaped, film-shaped) member is viewed as a whole and as a whole. ) points to the plane coincident with the plane direction of In addition, the normal direction used for a plate-shaped (sheet-like, film-like) member refers to the normal direction with respect to the plate surface (sheet surface, film surface) of the member.

In addition, terms such as "parallel", "orthogonal", "same", "equivalent", etc., lengths, angles, and physical Regarding the value of the characteristic, etc., analysis will be made including the range of the extent to which the same function can be expected, without being tied to a strict meaning.

(deposition mask device)

First, an example of a deposition mask device including a deposition mask, which is a subject of a manufacturing method, will be described with reference to FIGS. 1 to 6 . Here, FIG. 1 is a plan view showing an example of a deposition mask device including a deposition mask, and FIG. 2 is a diagram for explaining a method of using the deposition mask device shown in FIG. 1 . FIG. 3 is a plan view showing the deposition mask from the first surface side, and FIGS. 4 to 6 are cross-sectional views at respective positions in FIG. 3 .

The deposition mask apparatus 10 shown in FIGS. 1 and 2 includes a plurality of deposition masks 20 including substantially rectangular metal plates 21 and a frame 15 installed on the periphery of the plurality of deposition masks 20 . ) is provided. In each deposition mask 20, a plurality of through holes 25 formed by etching the metal plate 21 having first and second surfaces 21a and 21b opposed to each other from at least the first surface 21a, is formed As shown in FIG. 2, the deposition mask device 10 is supported in the deposition device 90 so that the deposition mask 20 faces the lower surface of a substrate to be deposited, for example, a glass substrate 92. , used for the deposition of deposition materials onto substrates.

Inside the deposition apparatus 90, the deposition mask 20 and the glass substrate 92 are brought into close contact with each other by magnetic force from a magnet (not shown). Inside the deposition apparatus 90, below the deposition mask apparatus 10, a crucible 94 for accommodating an evaporation material (an organic light emitting material as an example) 98, and a heater 96 for heating the crucible 94 ) is placed. The evaporation material 98 in the crucible 94 vaporizes or sublimes by heating from the heater 96 and adheres to the surface of the glass substrate 92 . As described above, a plurality of through holes 25 are formed in the deposition mask 20, and the deposition material 98 is adhered to the glass substrate 92 through the through holes 25. As a result, the deposition material 98 is formed on the surface of the glass substrate 92 in a desired pattern corresponding to the position of the through hole 25 of the deposition mask 20 .

As described above, in this embodiment, the through holes 25 are arranged in a predetermined pattern in each effective area 22 . In addition, when color display is desired, the deposition mask 20 (deposition mask device 10) and the glass substrate 92 are relatively moved little by little along the arrangement direction of the through holes 25 (one direction described above). , the organic luminescent material for red, the organic luminescent material for green, and the organic luminescent material for blue may be sequentially deposited.

Further, the frame 15 of the deposition mask device 10 is provided on the periphery of the rectangular deposition mask 20 . The frame 15 holds the deposition mask attached so that the deposition mask 20 does not warp. The deposition mask 20 and the frame 15 are fixed to each other by, for example, spot welding.

The vapor deposition process is performed inside the vapor deposition apparatus 90 in a high-temperature atmosphere. Therefore, during the deposition process, the deposition mask 20, the frame 15, and the substrate 92 held inside the deposition apparatus 90 are also heated. At this time, the deposition mask, the frame 15, and the substrate 92 exhibit dimensional change behavior based on their respective coefficients of thermal expansion. In this case, if the thermal expansion coefficients of the deposition mask 20 or frame 15 and the substrate 92 differ greatly, positional displacement due to the difference in dimensional change between them occurs, and as a result, the adhesion on the substrate 92 occurs. The dimensional accuracy and positional accuracy of the evaporation material to be used will decrease. In order to solve such a problem, it is preferable that the thermal expansion coefficient of the deposition mask 20 and the frame 15 be equal to the thermal expansion coefficient of the substrate 92 . For example, when the glass substrate 92 is used as the substrate 92, as the material of the deposition mask 20 and the frame 15, an invar material which is an alloy obtained by adding 36% of nickel to iron can be used. .

(deposition mask)

* Next, the deposition mask 20 will be described in detail. As shown in FIG. 1 , in the present embodiment, the deposition mask 20 includes the metal plate 21 and has a substantially rectangular shape in plan view, and more precisely, a substantially rectangular outline in plan view. . The metal plate 21 of the deposition mask 20 includes an effective area 22 in which through holes 25 are formed in a regular arrangement, and a peripheral area 23 surrounding the effective area 22 . The peripheral area 23 is an area for supporting the effective area 22 and is not an area through which evaporation material intended to be deposited on the substrate passes. For example, in the deposition mask 20 used for evaporation of an organic light emitting material for an organic EL display device, the effective area 22 is a substrate (glass substrate 92 on which the organic light emitting material is deposited to form pixels). )) is a region within the deposition mask 20 facing the region above, that is, the region above the substrate that will form the display surface of the fabricated substrate for the organic EL display device. However, for various purposes, a through hole or a recess may be formed in the peripheral region 23 . In the example shown in Fig. 1, each effective region 22 has a substantially rectangular shape in plan view, and more precisely, a substantially rectangular outline in plan view.

In the illustrated example, the plurality of effective regions 22 of the deposition mask 20 are arranged in a line at predetermined intervals along one direction parallel to the longitudinal direction of the deposition mask 20 . In the illustrated example, one effective area 22 corresponds to one organic EL display device. That is, according to the deposition mask device 10 (deposition mask 20) shown in FIG. 1, multi-sided deposition is possible.

As shown in Fig. 3, in the illustrated example, the plurality of through holes 25 formed in each effective region 22 are provided at a predetermined pitch along two mutually orthogonal directions in the effective region 22, respectively. are arranged as An example of the through hole 25 formed in the metal plate 21 will be described in more detail with reference mainly to FIGS. 3 to 6 .

As shown in FIGS. 4 to 6 , the plurality of through holes 25 are formed on a first surface 20a on one side along the normal direction of the deposition mask 20 and in the normal direction of the deposition mask 20 . It extends between the 2nd surface 20b which becomes the other side along , and penetrates the deposition mask 20. In the illustrated example, as described later in detail, a first concave portion 30 is formed in the metal plate 21 from the first surface 21a side of the metal plate 21, which is one side in the normal direction of the deposition mask. Formed by etching, a second concave portion 35 is formed in the metal plate 21 from the side of the second surface 21b, which is the other side in the normal direction of the metal plate 21, and this first concave portion ( 30) and the second concave portion 35 form a through hole 25.

3 to 6, deposition at each position along the normal direction of the deposition mask 20 from the first surface 20a side of the deposition mask 20 toward the second surface 20b side. The cross-sectional area of each first concave portion 30 in the cross section along the plate surface of the mask 20 gradually decreases. As shown in FIG. 3 , the wall surface 31 of the first concave portion 30 extends in a direction crossing the normal direction of the deposition mask 20 over its entire area, and It is exposed toward one side along the normal direction. Similarly, the cross-sectional area of each second concave portion 35 in the cross section along the plate surface of the deposition mask 20 at each position along the normal direction of the deposition mask 20 is the second surface of the deposition mask 20 ( It may become smaller gradually from the 20b) side toward the 1st surface 20a side. The wall surface 36 of the second concave portion 35 extends in a direction crossing the normal direction of the deposition mask 20 over its entire area, and extends on the other side along the normal direction of the deposition mask 20. are exposed towards

4 to 6, the wall surface 31 of the first concave portion 30 and the wall surface 36 of the second concave portion 35 are connected via a circumferential connection portion 41. are connected The connection portion 41 includes a wall surface 31 of the first concave portion 30 inclined with respect to the normal direction of the deposition mask and a wall surface 36 of the second concave portion 35 inclined with respect to the normal direction of the deposition mask. It is partitioned by the ridgeline of this confluence protrusion. Then, the connecting portion 41 defines a penetrating portion 42 in which the area of the through hole 25 is the smallest in plan view of the deposition mask 20 .

4 to 6, on the surface on the other side along the normal direction of the deposition mask, that is, on the second surface 20b of the deposition mask 20, the two adjacent through holes 25 are , and are spaced apart from each other along the plane of the deposition mask. That is, as in the manufacturing method described later, the metal plate 21 is etched from the side of the second surface 21b of the metal plate 21 corresponding to the second surface 20b of the deposition mask 20 to form the second concave portion. When 35 is manufactured, the second surface 21b of the metal plate 21 remains between two adjacent second concave portions 35 .

Meanwhile, as shown in FIGS. 4 to 6 , on one side along the normal direction of the deposition mask, that is, on the side of the first surface 20a of the deposition mask 20, two adjacent first concave portions ( 30) is connected. That is, as in the manufacturing method described later, the metal plate 21 is etched from the side of the first surface 21a of the metal plate 21 corresponding to the first surface 20a of the deposition mask 20 to form the first concave portion. In the case of forming (30), the first surface 21a of the metal plate 21 does not remain between the two adjacent first concave portions 30. That is, the first surface 21a of the metal plate 21 is etched throughout the effective region 22 . According to the first surface 20a of the deposition mask 20 formed by the first concave portion 30, as shown in FIG. 2, the first surface 20a of the deposition mask 20 is the deposition material ( 98), the use efficiency of the evaporation material 98 can be effectively improved.

When the deposition mask device 10 is accommodated in the deposition device 90 as shown in FIG. 2 , as shown by the dotted-dot chain line in FIG. 4 , the first surface 20a of the deposition mask 20 contains the deposition material 98) is located on the side of the holding crucible 94, and the second surface 20b of the deposition mask 20 faces the glass substrate 92. Therefore, the evaporation material 98 passes through the first concave portion 30 whose cross-sectional area gradually decreases and adheres to the glass substrate 92 . As indicated by arrows in FIG. 4 , the evaporation material 98 not only moves along the normal direction of the glass substrate 92 from the crucible 94 toward the glass substrate 92, but also moves in the normal direction of the glass substrate 92. It may also move in a direction that is greatly inclined with respect to . At this time, when the thickness of the deposition mask 20 is large, most of the obliquely moving deposition material 98 passes through the through hole 25 before reaching the glass substrate 92, on the wall surface of the first concave portion 30. (31) is reached and attached. Further, in the region facing the through hole 25 on the glass substrate 92, a region where the evaporation material 98 can easily reach and a region where it is difficult to reach occur. Therefore, in order to save expensive evaporation materials by increasing the utilization efficiency of evaporation materials (film formation efficiency: ratio of adhesion to the glass substrate 92), and to perform film formation using expensive evaporation materials stably and uniformly within a desired area, , it becomes important to configure the deposition mask 20 so that the evaporation material 98 moving obliquely reaches the glass substrate 92 as much as possible. That is, in the cross sections of FIGS. 4 to 6 orthogonal to the sheet surface of the deposition mask 20, the connection portion 41 serving as the portion having the minimum cross-sectional area of the through hole 25 and the first concave portion 30 It is advantageous to sufficiently increase the minimum angle θ1 (see FIG. 4 ) formed by a straight line L1 passing through another arbitrary position of the wall surface 31 with respect to the normal direction of the deposition mask 20 .

As one of the methods for increasing the angle θ1, the thickness of the deposition mask 20 is reduced, whereby the wall surface 31 of the first concave portion 30 or the wall surface of the second concave portion 35 ( 36) can be considered. That is, it can be said that it is preferable to use the metal plate 21 having a thickness as small as possible within a range capable of securing the strength of the deposition mask 20 as the metal plate 21 for constituting the deposition mask 20. .

As another method for increasing the angle θ1, optimizing the contour of the first concave portion 30 is also conceivable. For example, according to the present embodiment, when the wall surfaces 31 of the two adjacent first concave portions 30 are joined, compared with a concave portion having a wall surface (outline) indicated by a dotted line that does not join another concave portion. Thus, the angle θ1 can be greatly increased. The reason for this is explained below.

As explained in detail later, the 1st recessed part 30 is formed by etching the 1st surface 21a of the metal plate 21. The wall surface of the concave portion formed by etching generally has a curved shape that becomes convex toward the erosion direction. Therefore, the wall surface 31 of the concave portion formed by etching rises steeply in the area on the etching start side, and in the area opposite to the etching start side, that is, on the deepest side of the concave portion, the normal line of the metal plate 21 direction is relatively large. On the other hand, in the illustrated deposition mask 20, since the wall surfaces 31 of the two adjacent first concave portions 30 are joined at the start side of etching, the wall surfaces of the two first concave portions 30 ( The outer contour of the portion 43 where the distal edge 32 of 31) joins is not a steeply raised shape, but a chamfered shape. Accordingly, the wall surface 31 of the first concave portion 30 forming most of the through hole 25 can be effectively inclined with respect to the normal direction of the deposition mask. That is, the angle θ1 can be increased. Thereby, vapor deposition in a desired pattern can be stably performed with high precision while effectively improving the utilization efficiency of the evaporation material 98 .

By the way, in order to obtain the metal plate 21 with small thickness, it is necessary to increase the rolling ratio at the time of manufacturing the metal plate 21 by rolling a base material. However, the greater the rolling ratio, the greater the degree of unevenness of deformation based on rolling. For example, the elongation rate of the metal plate 21 differs depending on the position in the width direction (direction orthogonal to the conveyance direction of the base material), and as a result, the above-described wavy shape may appear on the metal plate 21. Here, consider a case where each of the deposition masks 20 shown in Fig. 1 is composed of an elongated metal plate obtained by cutting a metal plate obtained by rolling a base material along the longitudinal direction thereof. In this case, since the length of each deposition mask 20 is different, the pitch of each through hole 25 of the effective region 22 of each deposition mask 20 is different for each deposition mask 20, as a result. , a case where the positional accuracy of deposition is lowered and the utilization efficiency of the deposition material is lowered is conceivable. Therefore, in order to suppress the variation of the pitch of each through hole 25 in the effective area 22 of each deposition mask 20, thereby obtaining an organic EL display device in which the variation in size and position of pixels is small, as will be described later. As such, it is important to select and use the metal plate 21 with a small difference in elongation rate.

Next, the present embodiment including these configurations and its actions and effects will be described. Here, first, the manufacturing method of the metal plate used for manufacturing a deposition mask is demonstrated. Next, a method for manufacturing a deposition mask using the obtained metal plate will be described. After that, a method of depositing an evaporation material on a substrate using the obtained evaporation mask will be described.

(Method of manufacturing metal plate)

First, with reference to FIGS. 7(a), (b), 8, 9(a), (b), (c), (d) and FIG. Fig. 7(a) is a diagram showing a step of rolling a base material to obtain a metal sheet having a desired thickness, and Fig. 7(b) is a diagram showing a step of annealing the metal sheet obtained by rolling.

[rolling process]

First, as shown in Fig. 7(a), a base material 55 composed of an invar material is prepared, and this base material 55 is rolled into a rolling device 56 including a pair of rolling rolls 56a and 56b. ), it is conveyed along the conveyance direction indicated by the arrow D1. The base material 55 reaching between the pair of pressure rolls 56a and 56b is rolled by the pair of pressure rolls 56a and 56b, and as a result, the base material 55 is reduced in thickness and Together, they are stretched along the conveying direction. Thereby, the long metal plate 64 of thickness t ₀ can be obtained. As shown in Fig. 7(a), the winding body 62 may be formed by winding the elongated metal plate 64 around the core 61. Although the specific value of thickness t ₀ is not specifically limited, For example, it is in the range of 0.020 mm or more and 0.100 mm or less.

[anneal step]

After that, in order to remove residual stress accumulated in the elongated metal plate 64 by rolling, the elongated metal plate 64 is annealed using an annealing device 57 as shown in FIG. 7(b). As shown in Fig. 7(b), the annealing step may be performed while pulling the elongated metal plate 64 in the conveying direction (longitudinal direction). As a result, a long metal plate 64 having a thickness t ₀ in which residual stress is removed to some extent can be obtained. Also, the thickness t ₀ is usually equal to the maximum thickness Tb in the peripheral region 23 of the deposition mask 20 .

In addition, the form of a rolling process and annealing process is not specifically limited to the form shown to FIG.7(a), (b). For example, the rolling process may be performed using a plurality of pairs of pressure rolls 56a and 56b. Moreover, you may produce the long metal plate 64 of thickness t0 by repeating a rolling process and annealing process multiple times _. In addition, in (b) of FIG. 7 , an example in which the annealing step is performed while pulling the elongated metal plate 64 in the longitudinal direction has been shown, but is not limited to this, and the annealing step is performed when the elongated metal plate 64 is core ( 61) may be carried out. In addition, when the annealing process is performed in the state where the long metal plate 64 is wound around the core 61, the long metal plate 64 tends to bend depending on the winding diameter of the winding body 62 in some cases. Therefore, depending on the winding diameter of the winding body 62 or the material constituting the base material 55, it is advantageous to perform the annealing step while pulling the elongated metal plate 64 in the longitudinal direction.

[Inspection process]

After that, an inspection step of inspecting the degree of difference in elongation of the obtained elongated metal plate 64 is performed. Fig. 8 is a perspective view showing a metal plate obtained by the steps shown in Figs. 7(a) and (b). As shown in Fig. 8, the elongated metal plate 64 at least partially has a wavy shape due to the fact that the length in the longitudinal direction D1 differs depending on the position in the width direction D2. Here, the longitudinal direction D1 is a direction parallel to the transport direction when the base material 55 is rolled, and the width direction D2 is a direction orthogonal to the longitudinal direction D1. In Fig. 8, an end portion of the elongated metal plate 64 in the width direction D2 is denoted by numeral 64e.

A wavy shape appearing on the long metal plate 64 will be described. 9(a), (b), (c), and (d) are cross-sectional views taken along lines a-a, b-b, c-c, and d-d of FIG. 8 , respectively. Line a-a in FIG. 8 is a line extending in the longitudinal direction along the central portion 64c in the width direction of the elongated metal plate 64, and therefore, (a) in FIG. 9 is the central portion in the width direction of the elongated metal plate 64. A cross section of the elongated metal plate 64 at 64c is shown. 8 is a line extending in the longitudinal direction along the end 64e of the elongated metal plate 64 in the width direction, and therefore, (d) in FIG. 9 is a line in the width direction of the elongated metal plate 64 A cross section of the elongated metal plate 64 at the end portion 64e is shown. Central elongation appears in the elongated metal plate 64 according to the present embodiment, and for this reason, the degree of wave shape appearing in the elongated metal plate 64 at the central portion 64c in the width direction is a position slightly away from the central portion 64c, For example, it is larger than the extent of the wavy shape appearing on the elongated metal plate 64 at the position of b-b line of FIG. In addition, the elongated metal plate 64 according to the present embodiment also has ears, and for this reason, the degree of wave shape appearing on the elongated metal plate 64 at the end portion 64e in the width direction is at a position slightly away from the end portion 64e. , for example, greater than the degree of wave shape appearing on the elongated metal plate 64 at the position of line c-c in FIG. 8 .

In the inspection step, first, the length of the elongated metal plate 64 within a predetermined range in the longitudinal direction D1 is calculated at each position in the width direction D2. Here, “length” means the contour of the surface (first surface 64a or second surface 64b) of the elongated metal plate 64 in the longitudinal direction D1 along the wave shape appearing on the elongated metal plate 64. refers to the length of Specifically, as shown in (a), (b), (c) and (d) of FIG. 9, the long metal plate at the position indicated by the lines a-a, b-b, c-c and d-d in FIG. The lengths (la, lb, lc, and ld) of (64) are measured in consideration of the wavy shape appearing on the elongated metal plate 64 as well. A method for calculating the length of the long metal plate 64 is not particularly limited. For example, in the case of calculating the length la of the long metal plate 64 at the center portion 64c, first, a range-measuring device capable of measuring the distance to an object is set at the center portion ( At 64c), scan is performed on the elongated metal plate 64 along the longitudinal direction D1 of the elongated metal plate 64, whereby the height position of the surface of the elongated metal plate 64 is set at predetermined intervals along the longitudinal direction D1. Measure. This space|interval exists in the range of 1 mm or more and 5 mm or less, for example. Next, a curve connecting each measurement point smoothly is drawn, and then the length of this curve is calculated. Thereby, the length la of the long metal plate 64 in the center part 64c can be obtained. In addition, by repeating such a measurement while changing the position in the width direction D2, the length of the elongated metal plate 64 at each position in the width direction D2 can be obtained.

Next, the minimum value of the length of the elongated metal plate 64 obtained at each position in the width direction D2 is set as the standard length. In this embodiment, the length lb of the elongated metal plate 64 at the position indicated by the line bb in FIG. 8 is set as the standard length. Then, the ratio of the difference of the length of the elongated metal plate 64 at each position of the width direction D2 with respect to the standard length lb is computed as an elongation difference rate. For example, the elongation difference rate of the elongated metal plate 64 at the central portion 64c is derived by (la-lb)/lb. 10 is a graph showing a curve 80 of the calculated elongation difference rate. In Fig. 10, the horizontal axis represents the position of the elongated metal plate 64 in the width direction D2, and the vertical axis represents the elongation difference rate on the order of 10 ^-5 . At the upper end of the horizontal axis in FIG. 10 , positions in the width direction D2 when the central portion 64c in the width direction D2 is the origin are written in the order of mm. Further, at the lower end of the horizontal axis in FIG. 10 , the ratio of the position in the width direction D2 to the total width of the elongated metal plate 64 is indicated as %. In Fig. 10, as the long metal plate 64 for manufacturing the deposition mask 20, a case where one having an overall width of 500 mm is used is described. Therefore, for example, the ratio at a position separated by +100 mm from the central portion 64c in the width direction D2 is +20%. In Fig. 10, the elongation difference rates of the elongated metal plate 64 at the positions of the lines aa, bb, cc and dd in Fig. 8 are indicated by symbols A, B, C and D, respectively.

After that, the elongated metal plate 64 is sorted based on the obtained value of the elongation difference rate. Here, the elongated metal plate 64 is selected so that only the elongated metal plate 64 that satisfies all of the following conditions (1) to (3) is used in the manufacturing process of the deposition mask 20 described later.

(1) The elongation difference rate at the center portion R1 of the elongated metal plate 64 is 10×10 ^-5 or less;

(2) The elongation difference rate at the end portion 64e in the width direction D2 of the elongated metal plate 64 is 20×10 ^-5 or less; and

(3) the elongation difference rate at the end portion 64e is larger than the maximum value of the elongation difference rate at the central portion R1;

Hereinafter, the above conditions (1) to (3) are examined respectively. In Fig. 10, the central portion of the elongated metal plate 64 is indicated by reference numeral R1, and the peripheral portion located outside the central portion R1 is indicated by reference numeral R2. In this embodiment, the central portion R1 is defined as a portion that occupies 40% of the entire width of the elongated metal plate 64 including the central portion 64c in the width direction D2 of the elongated metal plate 64. .

In the elongated metal plate 64 in which central elongation and earing have occurred, as shown in FIG. 10 , the maximum value of the elongation difference rate generally appears near the central portion 64c in the width direction of the elongated metal plate 64 (point A ). In addition, the minimum value of the elongation difference ratio appears at a position slightly away from the central part in the width direction of the elongated metal plate 64 toward the periphery side (point B). Further, the elongation difference rate increases from point B toward the periphery in the width direction (point C), and the value of the elongation difference rate becomes the maximum at the end in the width direction (point D). Therefore, as shown by the one-dotted chain line in FIG. 10, the reference line 81 representing the elongation difference rate = 10 × 10 ^-5 in the central portion R1 and the elongation difference rate = 20 × 10 ^-5 in the peripheral portion R2 When drawn, it means that the above-mentioned conditions (1) and (2) are satisfied that the curve 80 of the elongation difference rate is located below the reference line 81. In the example shown in Fig. 10, the above-mentioned conditions (1) and (2) are satisfied.

Regarding condition (3), the elongation difference rate at the end portion 64e in the width direction D2, that is, the elongation difference rate at point D is the maximum value of the elongation difference rate in the central portion R1 (in the example shown in FIG. 10, the point Elongation difference rate at A) is determined. In the example shown in Fig. 10, condition (3) described above is satisfied.

By performing such sorting, even when wavy shapes appear in the long metal sheet 64 due to the large rolling ratio of the long metal sheet 64, the degree of the wavy shape can be determined in the manufacturing process of the deposition mask 20 or later. It is possible to determine in advance whether or not it is a problem in the manufacturing process of the organic EL display device. As a result, the degree of difference in the lengths of the plurality of elongated deposition masks 20 produced simultaneously can be made within an allowable range. For this reason, it is possible to reduce the variation in the pitch of each through hole 25 in the effective region 22 of the deposition mask 20 to be manufactured, thereby increasing the dimensional accuracy and positional accuracy of the pixels of the organic EL display device. can In addition, the yield in the manufacturing process of the deposition mask 20 can be improved.

In addition, the method of obtaining the long metal plate 64 of total width 500mm which has the curve 80 of the elongation difference rate as shown in FIG. 10 is not specifically limited.

For example, by rolling the base material 55, a long metal plate having an overall width exceeding 500 mm, for example, an overall width of 700 mm is produced, and then both ends in the width direction of the long metal plate are within a predetermined range. By cutting across, you may manufacture the long metal plate 64 of width 500mm. Further, in a long metal sheet having a total width of 700 mm, there may be a portion where the elongation difference rate exceeds 20×10 ^-5 as indicated by the two-dot chain line in FIG. 10 . Even in this case, the elongated metal plate 64 satisfying the above-mentioned conditions (1) to (3) can be obtained by cutting both ends over a predetermined range.

Alternatively, the elongated metal plate 64 satisfying the above conditions (1) to (3) may be produced by rolling without cutting both ends over a predetermined range.

(Manufacturing method of vapor deposition mask)

Next, a method for manufacturing the deposition mask 20 using the elongated metal plate 64 selected as described above will be described mainly with reference to FIGS. 11 to 20 . In the manufacturing method of the deposition mask 20 described below, as shown in FIG. 11, a long metal plate 64 is supplied, a through hole 25 is formed in the long metal plate 64, and further, the long metal plate By cutting (64), the deposition mask 20 including the sheet metal plate 21 is obtained.

More specifically, a method of manufacturing the deposition mask 20, a step of supplying a long metal plate 64 extending in a strip shape, etching using a photolithography technique is applied to the long metal plate 64, and the long metal plate 64 ), a process of forming the first concave portion 30 from the side of the first surface 64a and etching using a photolithography technique are applied to the elongated metal plate 64 to form a second surface 64b on the elongated metal plate 64. ) side to form the second concave portion 35. And the through hole 25 is produced in the long metal plate 64 by the 1st recessed part 30 and the 2nd recessed part 35 formed in the long metal plate 64 communicating with each other. In the example shown in FIG. 11, the formation process of the 2nd concave part 35 is performed before the formation process of the 1st concave part 30, and the formation process of the 2nd concave part 35 and the 1st concave part Between the formation process of (30), the process of sealing the produced 2nd concave part 35 is further provided. Below, the details of each process are demonstrated.

11 shows a manufacturing apparatus 60 for manufacturing the deposition mask 20 . As shown in FIG. 11, first, a winding body 62 in which a long metal plate 64 is wound around a core 61 is prepared. Then, as this core 61 rotates and the winding body 62 is unwound, a long metal plate 64 extending in a belt shape as shown in Fig. 11 is supplied. In addition, the long metal plate 64 is formed with through holes 25 to form the sheet-shaped metal plate 21 and thus the deposition mask 20 .

The supplied long metal plate 64 is conveyed to the etching device (etching means) 70 by the conveyance roller 72 . Each process shown in Figs. 12 to 20 is performed by the etching means 70.

First, as shown in FIG. 12, a negative photosensitive resist material is applied on the first surface 64a (on the lower surface of the sheet of FIG. 12) and the second surface 64b of the elongated metal plate 64. Thus, resist films 65c and 65d are formed on the long metal plate 64. Next, exposure masks 85a and 85b are prepared so as not to allow light to pass through the areas of the resist films 65c and 65d to be removed, and the exposure masks 85a and 85b are applied to the resist film as shown in FIG. 13, respectively. Place it above (65c, 65d). As the exposure masks 85a and 85b, for example, a dry glass plate in which light is not transmitted to a region to be removed in the resist films 65c and 65d is used. Thereafter, the exposure masks 85a and 85b are sufficiently brought into close contact with the resist films 65c and 65d by vacuum adhesion.

Further, as the photosensitive resist material, a positive-type one may be used. In this case, as an exposure mask, an exposure mask that transmits light to a region to be removed in the resist film is used.

Here, according to this embodiment, the elongated metal plate 64 whose elongation difference rate in the edge part 64e is larger than the maximum value of the elongation difference rate in the center part R1 is used as mentioned above. That is, the degree of wavy at the end portion 64e in the width direction D2 of the elongated metal plate 64 is greater than the degree of wavy at the central portion 64c in the width direction D2 of the elongated metal plate 64. has been In general, in vacuum adhesion, air existing between the resist films 65c and 65d provided on the elongated metal plate 64 and the exposure masks 85a and 85b is blown through the elongated metal plate 64 and the resist film 65c, By discharging to the outside from the end of the laminated body of 65d), close contact between the resist films 65c and 65d and the exposure masks 85a and 85b is realized. Here, for example, if the degree of wavy shape at the end portion 64e of the long metal plate 64 is smaller than the degree of wavy shape at the central portion 64c of the long metal plate 64, the region near the end portion of the laminated body is , it is possible to come into close contact with the exposure masks 85a and 85b prior to the area near the central portion of the laminate, and as a result, the exhaust passage for air existing near the central portion of the laminate is lost. On the other hand, according to this embodiment, since the degree of wavy at the end portion 64e of the elongated metal plate 64 is greater than the degree of wavy at the central portion 64c of the elongated metal plate 64, the central portion of the laminated body It is possible to reliably secure a discharge path for air existing in the vicinity, and for this reason, the exposure masks 85a and 85b can be sufficiently brought into close contact with the resist films 65c and 65d over the entire area.

After that, the resist films 65c and 65d are exposed over the exposure masks 85a and 85b, and the resist films 65c and 65d are also developed. As described above, as shown in FIG. 14 , a resist pattern (simply referred to as a resist) 65a is formed on the first surface 64a of the elongated metal plate 64, and the second surface of the elongated metal plate 64 is formed. A resist pattern (simply referred to as a resist) 65b may be formed on the surface 64b.

15, using the resist pattern 65b formed on the elongated metal plate 64 as a mask and using an etchant (for example, ferric chloride solution), the elongated metal plate 64 is coated with a second layer. Etching is performed on the surface 64b side. For example, the second surface 64b of the elongated metal plate 64 is passed over the resist pattern 65b from a nozzle disposed on the side facing the second surface 64b of the elongated metal plate 64 to which the etchant is conveyed. sprayed towards As a result, as shown in Fig. 15, erosion by the etchant proceeds in the region of the elongated metal plate 64 that is not covered by the resist pattern 65b. As described above, a large number of second concave portions 35 are formed in the elongated metal plate 64 from the side of the second surface 64b.

After that, as shown in Fig. 16, the formed second concave portion 35 is covered with a resin 69 resistant to the etching solution. That is, the second concave portion 35 is sealed by the resin 69 resistant to the etching solution. In the example shown in FIG. 16 , a film of resin 69 is formed so as to cover not only the formed second concave portion 35 but also the second surface 64b (resist pattern 65b).

Next, as shown in Fig. 17, the second etching process is performed on the elongated metal plate 64. In the etching of the second time, the long metal plate 64 is etched only from the first surface 64a side, and formation of the first concave portion 30 proceeds from the first surface 64a side. This is because the second surface 64b side of the elongated metal plate 64 is coated with a resin 69 resistant to etching. Therefore, the shape of the second concave portion 35 formed in a desired shape by the first etching is not damaged.

Erosion by etching is performed at a portion of the elongated metal plate 64 that is in contact with the etching solution. Therefore, erosion proceeds not only in the normal direction (thickness direction) of the elongated metal plate 64, but also in the direction along the plate surface of the elongated metal plate 64. As a result, as shown in FIG. 18, etching proceeds in the normal direction of the long metal plate 64 so that the first concave portion 30 not only connects to the second concave portion 35, but also the resist pattern 65a. The two first concave portions 30 respectively formed at positions facing the adjacent two holes 66a join from the other side of the bridge portion 67a located between the two holes 66a.

As shown in Fig. 19, etching from the side of the first surface 64a of the long metal plate 64 proceeds further. As shown in FIG. 19, a confluence portion 43 formed by joining two adjacent first concave portions 30 is spaced apart from the resist pattern 65a, and the confluence portion below the resist pattern 65a In (43), erosion by etching also proceeds in the normal direction (thickness direction) of the metal plate 64. As a result, the confluence portion 43 sharpened toward one side along the normal direction of the deposition mask is etched from one side along the normal direction of the deposition mask, and chamfered as shown in FIG. 19 . Accordingly, the inclination angle θ1 of the wall surface 31 of the first concave portion 30 with respect to the normal direction of the deposition mask can be increased.

In this way, the erosion of the first surface 64a of the elongated metal plate 64 by etching proceeds within the entire area constituting the effective area 22 of the elongated metal plate 64 . As a result, the maximum thickness Ta along the normal direction of the elongated metal plate 64 in the region constituting the effective region 22 becomes smaller than the maximum thickness Tb of the elongated metal plate 64 before etching. .

As described above, the etching from the side of the first surface 64a of the elongated metal plate 64 proceeds by a predetermined amount, and the second etching of the elongated metal plate 64 is completed. At this time, the first concave portion 30 extends along the thickness direction of the elongated metal plate 64 to a position reaching the second concave portion 35, whereby the first concave portion 30 communicating with each other and a through hole 25 is formed in the elongated metal plate 64 by the second concave portion 35 .

After that, as shown in Fig. 20, the resin 69 is removed from the long metal plate 64. The resin film 69 can be removed by using, for example, an alkali-based stripper. Further, when an alkali-based stripper is used, as shown in Fig. 20, the resist patterns 65a and 65b are removed simultaneously with the resin 69.

The elongated metal plate 64 having the plurality of through holes 25 formed in this way is cut by a cutting device (cutting means) ( 73) is returned. In addition, the supply core 61 described above is rotated through the tension (tensile force) acting on the elongated metal plate 64 by the rotation of the conveying rollers 72 and 72, and the elongated metal plate 64 is removed from the winding body 62. ) is to be supplied.

After that, the long metal plate 64 on which a plurality of concave portions 61 are formed is cut into a predetermined length and width by a cutting device (cutting means) 73, thereby forming a sheet metal plate on which a plurality of through holes 25 are formed. (21) is obtained.

As described above, the deposition mask 20 including the metal plate 21 in which many through holes 25 are formed is obtained. According to this embodiment here, the 1st surface 21a of the metal plate 21 is etched over the whole area of the effective area|region 22. For this reason, the thickness of the effective region 22 of the deposition mask 20 is reduced, and the front edge 32 of the wall surface 31 of the two first concave portions 30 formed on the first surface 21a side. The outer contour of the portion 43 where ) joins can be made into a chamfered shape. Accordingly, the angle θ1 described above can be increased, thereby improving the efficiency of use of the evaporation material and the positioning accuracy of the evaporation.

By the way, cutting the elongated metal plate 64 having a wavy shape to a predetermined width along the longitudinal direction is such that the length of each deposition mask 20 including the elongated metal plate 21 obtained after cutting is the metal plate ( 21) means different things depending on the cut position, that is, the position in the width direction of the elongated metal plate 64. Here, according to this embodiment, as described above, the elongated metal plate 64 selected in advance based on the elongation difference rate in the width direction D2 is used. For this reason, even when the elongated metal plate 64 has a wavy shape, the degree of difference in the lengths of a plurality of deposition masks 20 produced simultaneously can be made within an allowable range. Therefore, according to the present embodiment, the thickness of the effective region 22 of the deposition mask 20 is reduced, and the inclination angle θ1 of the wall surface 31 of the first concave portion 30 of the deposition mask 20 is reduced. To increase the efficiency of use of evaporation materials and the positional accuracy of evaporation, to reduce the variation in the pitch of each through hole 25 of the effective area 22 of the deposition mask 20, and the deposition mask manufacturing process It is possible to achieve both improvement in the yield in the manufacturing process of the deposition mask 20 by increasing the adhesion in the exposure process during exposure. Accordingly, it is possible to stably provide the deposition mask 20 having excellent characteristics.

(deposition method)

Next, a method of depositing an evaporation material on the substrate 92 using the obtained evaporation mask 20 will be described. First, as shown in FIG. 2 , the deposition mask 20 is brought into close contact with the substrate 92 . At this time, by placing the deposition mask 20 on the frame 15, the surface of the deposition mask 20 is parallel to the surface of the substrate 92. Here, according to the present embodiment, the elongated metal plate 64 selected in advance based on the elongation difference rate in the width direction D2 is used. For this reason, compared to the case where such sorting is not performed, the variation in the length of each deposition mask 20 and the variation in the pitch of each through hole 25 in the effective region 22 are uniformly reduced. . Therefore, the evaporation material can be deposited on the substrate 92 with high positional accuracy. Therefore, in the case of forming the pixels of the organic EL display device by vapor deposition, the dimensional accuracy and positional accuracy of the pixels of the organic EL display device can be improved. This makes it possible to manufacture a high-precision organic EL display device.

In addition, in the present embodiment described above, an example in which the length of the elongated metal plate 64 at each position in the width direction D2 of the elongated metal plate 64 is calculated without cutting the elongated metal plate 64 in the longitudinal direction. showed However, it is not limited to this, and after cutting the elongated metal plate 64 to an appropriate length in the longitudinal direction, the length of the cut metal plate is calculated at each position in the width direction D2, and the metal plate is based on the result. selection may be performed.

In this embodiment, an example in which the first surface 21a of the metal plate 21 is etched over the entire area of the effective region 22 has been shown. However, it is not limited to this, and the first surface 21a of the metal plate 21 may be etched only in a part of the effective region 22 .

Example

Next, the present invention will be described more specifically by examples, but the present invention is not limited to the description of the following examples, unless the gist thereof is exceeded.

(Sample 1)

First, a winding body (first winding body) in which a long metal plate is wound was manufactured by performing the above-described rolling process and annealing process on a base material composed of an invar material. Then, as shown in FIG. 21, the 1st sample 100 which consists of a metal plate with a width of 500 mm and a projected length of 700 mm was obtained by cutting the front-end|tip part of the 1st winding body using a shearing machine. In addition, "projection length" is the length (dimension in the rolling direction) of the metal plate when the metal plate is viewed from directly above, that is, when the wavy shape of the metal plate is ignored. The width of the first sample 100 refers to the distance between the pair of end portions 101 and 102 of the first sample 100 in the width direction. The pair of end portions 101 and 102 of the first sample 100 are formed by passing through a cutting process in which both ends in the width direction of the metal sheet obtained by the rolling process and the annealing process are cut over a predetermined range, It extends almost straight.

Next, as shown in FIG. 21 , the first sample 100 was horizontally loaded on the surface plate 110 . At that time, the first sample 100 was gently placed on the surface plate 110 so that a partial concave portion did not occur in the first sample 100. Next, at one end 101 of the first sample 100, the actual length of the first sample 100 in the area of the projected length of 500 mm, that is, the length considering the wavy shape was measured. In addition, the area|region of 500 mm of projection length means the area|region excluding the area|region located within 100 mm from the both ends 103 and 104 in the longitudinal direction of the sample 1 from the 1st sample 100 with a projection length of 700 mm. Excluding the area within 100 mm from both ends 103 and 104 from the measurement target is to prevent the influence of distortion of the first sample 100 due to cutting by the shear from affecting the length measurement result. In Fig. 21, an area with a projected length of 500 mm is indicated by a chain dotted line.

In the measurement, as indicated by the arrow s in FIG. 21 , a distance measuring device using laser light is moved relative to the first sample 100 along the longitudinal direction of the first sample 100, and The height position of the surface at one end 101 of one sample 100 was measured at intervals of 1 mm. Further, a curve connecting each measurement point smoothly was drawn, and then the length of this curve was calculated. As a ranging device for measuring the height position of the surface of the first sample 100, OPTELICS H1200 manufactured by Lasertec Co., Ltd., which is a laser microscope, was used. In addition, the element moved during measurement may be either the ranging device or the first sample 100, but here, by using an auto stage of 500 mm × 500 mm as a surface plate on which the first sample 100 is placed, the sample ( 100) was moved to measure. A laser interferometer was used for control of the auto stage in the XY direction. In this way, the length of the first sample 100 at one end 101 was measured.

Next, at a position displaced by 20 mm from one end 101 to the other end 102, the length of the first sample 100 was similarly measured. The length of the first sample at each position in the width direction was measured by repeatedly performing the above-described measurement while changing the position of the first sample 100 in the width direction at a predetermined pitch p. Here, the pitch p was 20 mm. The obtained measurement result is the length measurement result at one end 101, the length measurement result at the other end 102, and the length measurement result at the central portion, and between the central portion and the end portions 101 and 102. contains the length measurement results of Further, the center portion is a portion in which the distance from the one end portion 101 is within a range of 150 mm or more and 350 mm or less when the one end portion 101 is taken as a standard. In addition, the measurement position in the width direction is set so that the length measurement is performed at the central part of the first sample 100, that is, at a position where the distances from one end 101 and the other end become equal.

Next, the minimum value of the length of the first sample 100 obtained at each position in the width direction was set as the standard length. After that, the ratio of the difference in the length of the first sample 100 at each position in the width direction to the standard length was calculated as an elongation difference rate. As a result, the elongation difference rate at one end 101 is 79.9×10 ^-5 , and the elongation difference rate at the other end 102 is 71.2×10 ^-5 , and the maximum value of the elongation difference rate at each position in the central portion is It was 15.8×10 ^-5 .

As a result of comparing the calculation result of the elongation difference rate in the first sample 100 with the conditions (1) to (3) described above, in the first sample 100, condition (3) was satisfied, but condition (1) ) and (2) were not satisfied. Accordingly, it is determined that the first sample 100 cannot be used as a material for manufacturing a deposition mask.

In addition, many deposition masks provided with five effective regions along the longitudinal direction were manufactured using the metal plate of the first winding body from which the above-described first sample 100 was obtained. A large number of through holes are formed in a regular arrangement in each effective region of each deposition mask. Next, in order to evaluate the positional accuracy of the obtained deposition mask, the total pitch of each deposition mask was measured, and the degree of variation of the total pitch was calculated.

Here, the total pitch is the distance between two predetermined points in the deposition mask. As long as the positional accuracy of the deposition mask can be evaluated, the set location of the two points is not particularly limited. Here, a predetermined mark formed in the vicinity of the effective area located on one end side of the deposition mask and The distance between predetermined marks formed in the vicinity of the effective area located on the end side was measured as a total pitch. The total pitch in this case is designed to be about 600 mm.

As an index of the degree of total pitch variation, a value obtained by multiplying the standard deviation (σ) of total pitch measurement values of each deposition mask by 3, so-called 3σ, was used. The variation (3σ) of the total pitch measured value of the vapor deposition mask obtained from the first winding body was 35.2 µm. In addition, the n number at the time of calculating the standard deviation (σ) was set so that the value of the standard deviation (σ) had sufficient certainty in performing a comparison with each sample described later. Specifically, n number was set to 400.

(second sample)

The 2nd sample containing the metal plate of width 500mm and projection length 700mm was obtained by cutting out the front-end|tip part of the 2nd winding body different from the 1st winding body mentioned above. Then, in the same manner as in the case of the first sample described above, the length of the second sample was measured at each position in the width direction, and the elongation difference rate was calculated. As a result, the difference in extension at one end was 24.7 × 10 ^-5 , the difference in extension at the other end was 29.8 × 10 ^-5 , and the maximum value of the difference in extension at each position in the central part was 1.0 × 10 ^-5 . .

As a result of comparing the calculation result of the elongation difference ratio in the second sample with the conditions (1) to (3) described above, in the second sample, conditions (1) and (3) were satisfied, but condition (2) Not satisfied. Therefore, it is determined that the second sample cannot be used as a material for manufacturing a deposition mask.

Further, in the same manner as in the case of the first sample described above, a plurality of deposition masks having a plurality of through holes were manufactured using the metal plate of the second winding body. Next, in the same manner as in the case of the first sample described above, the total pitch of each obtained deposition mask was measured, and the variation (3σ) of the measured total pitch value was calculated. As a result, the value of 3σ was 16.1 µm.

(third sample)

A third sample containing a metal plate having a width of 500 mm and a projected length of 700 mm was obtained by cutting off the front end of the third winding body different from the first winding body and the second winding body described above. Next, in the same manner as in the case of the first sample described above, the length of the third sample was measured at each position in the width direction, and the elongation difference rate was calculated. As a result, the difference in extension at one end was 18.1 × 10 ^-5 , the difference in extension at the other end was 19.0 × 10 ^-5 , and the maximum value of the difference in extension at each position in the central part was 13.2 × 10 ^-5 . .

As a result of comparing the calculation result of the elongation difference ratio in the third sample with the conditions (1) to (3) described above, in the third sample, conditions (2) and (3) were satisfied, but condition (1) Not satisfied. Therefore, it is determined that the third sample cannot be used as a material for manufacturing a deposition mask.

Further, in the same manner as in the case of the first sample described above, a plurality of deposition masks having a plurality of through holes were manufactured using the metal plate of the third winding body. Next, in the same manner as in the case of the first sample described above, the total pitch of each obtained deposition mask was measured, and the variation (3σ) of the measured total pitch value was calculated. As a result, the value of 3σ was 14.2 μm.

(4th sample)

A fourth sample containing a metal plate having a width of 500 mm and a projected length of 700 mm was obtained by cutting off the front end of the fourth winding body different from the above-described first winding body to the third winding body. Next, in the same manner as in the case of the first sample described above, the length of the fourth sample was measured at each position in the width direction, and the elongation difference rate was calculated. As a result, the difference in extension at one end was 26.8 × 10 ^-5 , the difference in extension at the other end was 18.6 × 10 ^-5 , and the maximum value of the difference in extension at each position in the central part was 3.9 × 10 ^-5 . .

As a result of comparing the calculation result of the elongation difference ratio in the fourth sample with the conditions (1) to (3) described above, in the fourth sample, conditions (1) and (3) were satisfied, but condition (2) Not satisfied. Therefore, it is determined that the fourth sample cannot be used as a material for manufacturing a deposition mask.

Further, in the same manner as in the case of the first sample described above, a plurality of deposition masks having a plurality of through holes were manufactured using the metal plate of the fourth winding body. Next, in the same manner as in the case of the first sample described above, the total pitch of each obtained deposition mask was measured, and the variation (3σ) of the measured total pitch value was calculated. As a result, the value of 3σ was 13.5 µm.

(5th sample)

The 5th sample containing the metal plate of width 500mm and projected length 700mm was obtained by cutting out the front-end|tip part of the 5th winding body different from the above-mentioned 1st winding body - 4th winding body. Next, in the same manner as in the case of the first sample described above, the length of the fifth sample was measured at each position in the width direction, and the elongation difference rate was calculated. As a result, the difference in extension at one end was 18.2 × 10 ^-5 , the difference in extension at the other end was 12.3 × 10 ^-5 , and the maximum value of the difference in extension at each position in the central part was 9.1 × 10 ^-5 . .

As a result of comparing the calculation result of the elongation difference rate in the fifth sample and the conditions (1) to (3) described above, all of the conditions (1) to (3) were satisfied in the fifth sample. Therefore, it is determined that the fifth sample can be used as a material for manufacturing a deposition mask.

Further, in the same manner as in the case of the first sample described above, a plurality of deposition masks having a plurality of through holes were manufactured using the metal plate of the fifth winding body. Next, in the same manner as in the case of the first sample described above, the total pitch of each obtained deposition mask was measured, and the variation (3σ) of the measured total pitch value was calculated. As a result, the value of 3σ was 5.6 µm.

(Sample 6)

The 6th sample containing the metal plate of width 500mm and projection length 700mm was obtained by cutting out the front-end|tip part of the 6th winding body different from the above-mentioned 1st winding body - 5th winding body. Next, in the same manner as in the case of the first sample described above, the length of the sixth sample was measured at each position in the width direction, and the elongation difference rate was calculated. As a result, the difference in extension at one end was 18.2 × 10 ^-5 , the difference in extension at the other end was 8.8 × 10 ^-5 , and the maximum value of the difference in extension at each position in the central part was 9.1 × 10 ^-5 . .

As a result of comparing the calculation result of the elongation difference rate in the sixth sample and the conditions (1) to (3) described above, in the third sample, conditions (1) and (2) were satisfied, but condition (3) Not satisfied. Therefore, it is determined that the sixth sample cannot be used as a material for manufacturing a deposition mask.

Further, in the same manner as in the case of the first sample described above, a plurality of deposition masks having a plurality of through holes were manufactured using the metal plate of the sixth winding body. Next, in the same manner as in the case of the first sample described above, the total pitch of each obtained deposition mask was measured, and the variation (3σ) of the measured total pitch value was calculated. As a result, the value of 3σ was 12.6 µm.

(Sample 7)

The 7th sample containing the metal plate of 500 mm in width and 700 mm in projection length was obtained by cutting out the front-end|tip part of the 7th winding body different from the above-mentioned 1st winding body - 6th winding body. Then, in the same manner as in the case of the first sample described above, the length of the seventh sample was measured at each position in the width direction, and the elongation difference rate was calculated. As a result, the difference in extension at one end was 16.5 × 10 ^-5 , the difference in extension at the other end was 3.2 × 10 ^-5 , and the maximum value of the difference in extension at each position in the central part was 0.8 × 10 ^-5 . .

As a result of comparing the calculation result of the elongation difference rate in the seventh sample and the conditions (1) to (3) described above, all of the conditions (1) to (3) were satisfied in the seventh sample. Therefore, it is determined that the seventh sample can be used as a material for manufacturing a deposition mask.

Further, in the same manner as in the case of the first sample described above, a plurality of deposition masks having a plurality of through holes were manufactured using the metal plate of the seventh winding body. Next, in the same manner as in the case of the first sample described above, the total pitch of each obtained deposition mask was measured, and the variation (3σ) of the measured total pitch value was calculated. As a result, the value of 3σ was 4.3 µm.

In this way, when the metal plates of the fifth and seventh winding bodies from which samples 5 and 7 were determined to be good based on the above conditions (1) to (3) were taken out, variations in the measured value of the total pitch of the deposition mask ( The value of 3σ) could be made small, specifically, 10 µm or less. On the other hand, when the metal plates of the first to fourth and sixth winding bodies from which samples 1 to 4 and 6 were determined to be defective based on the above conditions (1) to (3) were taken out, the total pitch of the deposition mask was measured. The value of the variation (3σ) of the value was large, specifically larger than 10 μm. From this point of view, it can be said that there is a strong correlation between the determination result based on the conditions (1) to (3) described above and the performance of the deposition mask obtained. That is, it can be said that the characteristics of the deposition mask obtained from the metal plate of the winding body can be predicted with high accuracy at the stage of the winding body by using the conditions (1) to (3) described above. Therefore, conditions (1) to (3) described above are considered to be effective judgment methods.

20: deposition mask
21: metal plate
21a: first surface of metal plate
21b: second side of metal plate
22: effective area
23: surrounding area
25: through hole
30: first concave portion
31: wall
35: second recess
36: wall
55: parent material
56: rolling device
57 annealing device
61: core
62: winding body
64: long metal plate
64a: first side of long metal plate
64b: second side of long metal plate
64c: central portion in the width direction of the elongated metal plate
64e: end in the width direction of the long metal plate
65a, 65b: resist pattern
65c, 65d: resist film
80: curve of elongation difference
81: baseline
85a, 85b: exposure mask

Claims (4)

A method for manufacturing a deposition mask having an effective region in which a plurality of through holes are formed and a peripheral region located around the effective region,
A step of preparing a metal plate which is a metal plate and has a wavy shape at least partially due to the length in the longitudinal direction being different depending on the position in the width direction;
a resist pattern forming step of forming a resist pattern on the metal plate;
an etching step of etching the metal plate using the resist pattern as a mask to form a concave portion defining and forming the through hole in a region of the metal plate constituting the effective region;
When the minimum value of the length of the metal plate is referred to as the reference length, and the ratio of the difference between the length of the metal plate at each position in the width direction of the metal plate to the reference length is referred to as the elongation difference rate, the following conditions (1 ) to (3) are satisfied,
(1) The elongation difference rate at the central portion in the width direction of the metal plate is 10×10 ^-5 or less;
(2) The elongation difference rate at the end of the metal plate in the width direction is 20×10 ^-5 or less; and
(3) the elongation difference rate at the end portion is greater than the maximum value of the elongation difference rate at the center portion;
The central part is a part that occupies 40% of the width of the metal plate, including the central part in the width direction of the metal plate,
Variation in the total pitch of the deposition mask is 10 μm or less,
The total pitch is a distance between a mark located near the effective region located on one end side of the deposition mask and a mark located near the effective region located on the other end side of the deposition mask;
The variation is a value obtained by multiplying a standard deviation of 400 measured values with the total pitch by 3. The method of claim 1 , wherein the resist pattern forming process comprises:
forming a resist film on the metal plate;
a step of vacuum-contacting an exposure mask to the resist film;
A method for manufacturing a deposition mask comprising a step of exposing the resist film to light in a predetermined pattern through the exposure mask. The method for manufacturing a deposition mask according to claim 1 or 2, wherein a coefficient of thermal expansion of the metal plate is equivalent to a coefficient of thermal expansion of a substrate on which an evaporation material is deposited via a deposition mask manufactured from the metal plate. The method for manufacturing a deposition mask according to claim 1 or 2, wherein the metal plate is made of an invar material.

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