JP2021042476A - Production method of vapor deposition mask, and production method of metal plate used for producing vapor deposition mask - Google Patents

Abstract

To produce a vapor deposition mask having little dispersion of the shape of an open hole.SOLUTION: A production method of a vapor deposition mask includes: a preparation step for preparing a metal plate comprising an iron alloy containing nickel, and including a first surface positioned on the substrate side to which a vapor deposition material passing through an open hole adheres, and a second surface positioned on the opposite side to the first surface; a surface layer removal step for removing a surface layer at least on the first surface side of the metal plate; and a processing step for forming an open hole on the metal plate by etching the metal plate.SELECTED DRAWING: Figure 16

Description

The present invention relates to a method for producing a vapor deposition mask. The present invention also relates to a method for manufacturing a metal plate used for manufacturing a vapor deposition mask.

In recent years, display devices used in portable devices such as smartphones and tablet PCs are required to have high definition, for example, a pixel density of 400 ppi or more. Further, even in a portable device, there is an increasing demand for supporting ultra full high-definition, and in this case, the pixel density of the display device is required to be, for example, 800 ppi or more.

Among display devices, organic EL display devices are attracting attention because of their good responsiveness, low power consumption, and high contrast. As a method of forming pixels of an organic EL display device, a method of forming pixels in a desired pattern by using a vapor deposition mask in which through holes arranged in a desired pattern are formed is known. Specifically, first, the vapor deposition mask is brought into close contact with the substrate for the organic EL display device, and then the adhered vapor deposition mask and the substrate are both put into the vapor deposition apparatus to deposit the organic material on the substrate. I do. As a result, pixels containing an organic material can be formed on the substrate with a pattern corresponding to the pattern of the through holes of the vapor deposition mask.

As a method for manufacturing a vapor deposition mask, for example, as disclosed in Patent Document 1, a method of forming a through hole in a metal plate by etching using a photolithography technique is known. For example, first, a first resist pattern is formed on the first surface of the metal plate by exposure / development processing, and a second resist pattern is formed on the second surface of the metal plate by exposure / development processing. Next, a region of the first surface of the metal plate that is not covered by the first resist pattern is etched to form a first opening on the first surface of the metal plate. Then, a region of the second surface of the metal plate that is not covered by the second resist pattern is etched to form a second opening on the second surface of the metal plate. At this time, by performing etching so that the first opening and the second opening communicate with each other, a through hole penetrating the metal plate can be formed. The metal plate for producing the vapor deposition mask is produced, for example, by rolling a base metal made of an iron alloy containing nickel.

Japanese Patent No. 5382259

As a result of diligent research by the present inventors, it was found that many inclusions are present in the surface layer of the rolled metal plate. In addition, as a result of diligent research by the present inventors, when a metal plate having many inclusions in the surface layer is etched to form a through hole in the metal plate, the shape of the through hole tends to vary. I found. If the shape of the through hole varies, the dimensional accuracy and position accuracy of the vapor-deposited material adhering to the substrate through the through hole will decrease.

An object of the present invention is to provide a method for producing a vapor-deposited mask that can effectively solve such a problem.

The present invention is a method for manufacturing a metal plate used for forming a plurality of through holes to manufacture a vapor deposition mask, in which a base metal made of an iron alloy containing nickel is rolled to form a first surface and a second surface. A method for producing a metal plate, comprising a rolling step of producing a metal plate including a surface and a surface layer removing step of removing at least the surface layer on the first surface side of the metal plate.

In the method for producing a metal plate according to the present invention, the surface layer removing step may remove the surface layer within a range of 0.5 μm or more and 20 μm or less in the thickness direction of the metal plate.

In the method for producing a metal plate according to the present invention, the surface layer removing step may include a wet etching step of bringing an etching solution into contact with at least the first surface of the metal plate.

In the method for manufacturing a metal plate according to the present invention, the wet etching step may include an injection step of injecting the etching solution toward the first surface with the first surface of the metal plate facing downward. Good.

In the method for producing a metal plate according to the present invention, the surface layer removing step may include a step of removing the surface layer on the first surface side and a step of removing the surface layer on the second surface side. ..

In the method for producing a metal plate according to the present invention, the thickness of the metal plate after the surface layer is removed by the surface layer removing step may be 5 μm or more and 50 μm or less.

The present invention is a method for manufacturing a vapor deposition mask in which a plurality of through holes are formed, the first surface of which is made of an iron alloy containing nickel and is located on the substrate side to which the vapor deposition material that has passed through the through holes adheres. A preparatory step of preparing a metal plate including a second surface located on the opposite side of the first surface, a surface layer removing step of removing at least the surface layer on the first surface side of the metal plate, and the above. A method for manufacturing a vapor deposition mask, comprising a processing step of etching a metal plate to form the through holes in the metal plate.

In the method for producing a thin-film deposition mask according to the present invention, the metal plate may be produced by rolling a base metal made of an iron alloy containing nickel in the preparation step.

In the method for producing a vapor deposition mask according to the present invention, the surface layer removing step may remove the surface layer within a range of 0.5 μm or more and 20 μm or less in the thickness direction of the metal plate.

In the method for producing a vapor-deposited mask according to the present invention, the surface layer removing step may include a wet etching step of bringing an etching solution into contact with at least the first surface of the metal plate.

In the method for producing a thin-film deposition mask according to the present invention, the wet etching step may include an injection step of injecting the etching solution toward the first surface of the metal plate with the first surface facing downward. Good.

In the method for producing a vapor-deposited mask according to the present invention, the surface layer removing step may include a step of removing the surface layer on the first surface side and a step of removing the surface layer on the second surface side. ..

In the method for producing a thin-film deposition mask according to the present invention, the thickness of the metal plate after the surface layer is removed by the surface layer removing step may be 5 μm or more and 50 μm or less.

According to the present invention, it is possible to manufacture a thin-film deposition mask having a small variation in the shape of the through holes.

It is a figure which shows the vapor deposition apparatus provided with the vapor deposition mask apparatus by one Embodiment of this invention. It is sectional drawing which shows the organic EL display apparatus manufactured by using the vapor deposition mask apparatus shown in FIG. It is a top view which shows the vapor deposition mask apparatus by one Embodiment of this invention. It is a partial plan view which shows the effective area of the vapor deposition mask shown in FIG. It is sectional drawing along the VV line of FIG. It is sectional drawing along the VI-VI line of FIG. It is sectional drawing along the line VII-VII of FIG. FIG. 5 is an enlarged cross-sectional view showing a through hole shown in FIG. 5 and a region in the vicinity thereof. It is a figure which shows the process which rolls a base metal, and obtains the metal plate which has a desired thickness. It is a figure which shows the process of annealing a metal plate obtained by rolling. It is sectional drawing which shows the appearance of inclusions in the surface layer of the metal plate obtained by rolling. It is sectional drawing which shows the process of forming the 1st recess by etching the metal plate shown in FIG. 11 from the 1st surface side. It is sectional drawing which shows the process which further advances the etching from the state shown in FIG. 12 and enlarges the 1st recess. It is sectional drawing which shows an example of the vapor deposition mask manufactured using the metal plate which has many inclusions in a surface layer. It is a schematic diagram for demonstrating an example of the manufacturing method of a thin-film deposition mask as a whole. It is a figure which shows the process of removing the surface layer of a metal plate. It is a figure which shows the metal plate which the surface layer was removed. It is a figure which shows the process of forming a resist film on a metal plate. It is a figure which shows the process of adhering an exposure mask to a resist film. It is a figure which shows the process of developing a resist film. It is a figure which shows the 1st surface etching process. It is a figure which shows the process of covering the 1st recess with resin. It is a figure which shows the 2nd surface etching process. It is a figure which shows the 2nd surface etching process which follows | FIG. It is a figure which shows the process of removing a resin and a resist pattern from a metal plate. It is a figure which shows one modification of the process of removing the surface layer of a metal plate.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, etc. are appropriately changed from those of the actual product and exaggerated for the convenience of illustration and comprehension.

1 to 23 are views for explaining an embodiment of the present invention. In the following embodiments and modifications thereof, a method for manufacturing a vapor deposition mask used for patterning an organic material on a substrate in a desired pattern when manufacturing an organic EL display device will be described as an example.
However, the present invention is not limited to such applications, and the present invention can be applied to vapor deposition masks used for various purposes.

In addition, in this specification, the terms "board", "sheet", and "film" are not distinguished from each other based only on the difference in designation. For example, "board" is a concept that includes members that can be called sheets or films.

Further, the "plate surface (sheet surface, film surface)" is a plate-like member (sheet-like) that is a target when the target plate-like (sheet-like, film-like) member is viewed as a whole and from a broad perspective. A surface that coincides with the plane direction of a member or film-like member). Further, the normal direction used for the plate-shaped (sheet-shaped, film-shaped) member refers to the normal direction with respect to the plate surface (sheet surface, film surface) of the member.

In addition, as used herein, terms such as "parallel," "orthogonal," "identical," "equivalent," and lengths and angles that specify the shape, geometrical conditions, and physical properties and their degree. In addition, the values of physical properties, etc. shall be interpreted including the range in which similar functions can be expected without being bound by the strict meaning.

(Evaporation equipment)
First, a thin-film deposition apparatus 90 that performs a thin-film deposition process for depositing a thin-film deposition material on an object will be described with reference to FIG. As shown in FIG. 1, the vapor deposition apparatus 90 includes a vapor deposition source (for example, a crucible 94), a heater 96, and a vapor deposition mask device 10 inside. Further, the vapor deposition apparatus 90 further includes an exhaust means for creating a vacuum atmosphere inside the vapor deposition apparatus 90. The crucible 94 accommodates a vapor deposition material 98 such as an organic light emitting material. The heater 96 heats the crucible 94 to evaporate the vapor deposition material 98 in a vacuum atmosphere. The vapor deposition mask device 10 is arranged so as to face the crucible 94.

(Evaporation mask device)
Hereinafter, the vapor deposition mask device 10 will be described. As shown in FIG. 1, the thin-film deposition mask device 10 includes a thin-film deposition mask 20 and a frame 15 that supports the thin-film deposition mask 20. The frame 15 supports the vapor deposition mask 20 in a state of being pulled in the plane direction so that the vapor deposition mask 20 does not bend. As shown in FIG. 1, the vapor deposition mask device 10 is arranged in the vapor deposition device 90 so that the vapor deposition mask 20 faces a substrate to which the vapor deposition material 98 is attached, for example, an organic EL substrate 92. In the following description, among the surfaces of the vapor deposition mask 20, the surface on the organic EL substrate 92 side is referred to as the first surface 20a, and the surface located on the opposite side of the first surface 20a is referred to as the second surface 20b.

As shown in FIG. 1, the vapor deposition mask device 10 may include a magnet 93 arranged on the surface of the organic EL substrate 92 opposite to the vapor deposition mask 20. By providing the magnet 93, the vapor deposition mask 20 can be attracted to the magnet 93 side by magnetic force, and the vapor deposition mask 20 can be brought into close contact with the organic EL substrate 92.

FIG. 3 is a plan view showing a case where the vapor deposition mask device 10 is viewed from the first surface 20a side of the vapor deposition mask 20. As shown in FIG. 3, the thin-film deposition mask device 10 includes a plurality of thin-film deposition masks 20. Each vapor deposition mask 20 includes a pair of long sides 26 and a pair of short sides 27, and has, for example, a rectangular shape. Each vapor deposition mask 20 is fixed to the frame 15 by, for example, spot welding at a pair of short sides 27 or a portion in the vicinity thereof.

The vapor deposition mask 20 includes a metal plate-shaped base material in which a plurality of through holes 25 penetrating the vapor deposition mask 20 are formed. The vaporized material 98 that has evaporated from the crucible 94 and reached the vapor deposition mask device 10 adheres to the organic EL substrate 92 through the through holes 25 of the vapor deposition mask 20. As a result, the vapor deposition material 98 can be deposited on the surface of the organic EL substrate 92 in a desired pattern corresponding to the position of the through hole 25 of the vapor deposition mask 20.

FIG. 2 is a cross-sectional view showing an organic EL display device 100 manufactured by using the vapor deposition device 90 of FIG. The organic EL display device 100 includes an organic EL substrate 92 and pixels including a vapor-deposited material 98 provided in a pattern.

If it is desired to display colors in a plurality of colors, a vapor deposition apparatus 90 equipped with a vapor deposition mask 20 corresponding to each color is prepared, and the organic EL substrate 92 is sequentially charged into each vapor deposition apparatus 90. Thereby, for example, the organic light emitting material for red, the organic light emitting material for green, and the organic light emitting material for blue can be vapor-deposited on the organic EL substrate 92 in this order.

By the way, the thin-film deposition treatment may be carried out inside the thin-film deposition apparatus 90 which has a high temperature atmosphere. In this case, the vapor deposition mask 20, the frame 15, and the organic EL substrate 92 held inside the vapor deposition apparatus 90 are also heated during the vapor deposition process. At this time, the vapor deposition mask 20, the frame 15, and the organic EL substrate 92 show the behavior of dimensional change based on their respective coefficients of thermal expansion.
In this case, if the coefficient of thermal expansion of the vapor deposition mask 20 or frame 15 and the organic EL substrate 92 are significantly different, a positional shift occurs due to the difference in their dimensional changes, and as a result, the organic EL substrate 92 adheres to the organic EL substrate 92. The dimensional accuracy and position accuracy of the vapor-deposited material deteriorate.

In order to solve such a problem, it is preferable that the coefficient of thermal expansion of the vapor deposition mask 20 and the frame 15 is a value equivalent to the coefficient of thermal expansion of the organic EL substrate 92. For example, when a glass substrate is used as the organic EL substrate 92, an iron alloy containing nickel can be used as the main material of the vapor deposition mask 20 and the frame 15. For example, as the material of the base material constituting the vapor deposition mask 20, an iron alloy containing 30% by mass or more and 54% by mass or less of nickel can be used. Specific examples of the nickel-containing iron alloy include an Invar material containing 34% by mass or more and 38% by mass or less of nickel, a super Invar material containing 30% by mass or more and 34% by mass or less of nickel, and further cobalt. Examples thereof include a low thermal expansion Fe—Ni based plating alloy containing nickel of mass% or more and 54 mass% or less.

If the temperatures of the vapor deposition mask 20, the frame 15 and the organic EL substrate 92 do not reach a high temperature during the vapor deposition process, the coefficient of thermal expansion of the vapor deposition mask 20 and the frame 15 is taken as the coefficient of thermal expansion of the organic EL substrate 92. It is not necessary to make the values equivalent. In this case, a material other than the above-mentioned iron alloy may be used as the material constituting the vapor deposition mask 20. For example, an iron alloy other than the above-mentioned nickel-containing iron alloy, such as an iron alloy containing chromium, may be used. As the iron alloy containing chromium, for example, a so-called stainless steel iron alloy can be used. Further, alloys other than iron alloys such as nickel and nickel-cobalt alloys may be used.

(Evaporation mask)
Next, the vapor deposition mask 20 will be described in detail. As shown in FIG. 3, the vapor deposition mask 20 is composed of a pair of ears (first ear portion 17a and second ear portion 17b) including a pair of short sides 27 of the vapor deposition mask 20 and a pair of ear portions 17a and 17b. It includes an intermediate portion 18 located between them.

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

(Middle part)
Next, the intermediate portion 18 will be described. The intermediate portion 18 includes at least one effective region 22 in which a through hole 25 extending from the first surface 20a to the second surface 20b is formed, and a peripheral region 23 surrounding the effective region 22. The effective region 22 is a region of the vapor deposition mask 20 facing the display region of the organic EL substrate 92.

In the example shown in FIG. 3, the intermediate portion 18 includes a plurality of effective regions 22 arranged at predetermined intervals along the long side 26 of the vapor deposition mask 20. One effective area 22 corresponds to the display area of one organic EL display device 100. Therefore, according to the thin-film deposition mask device 10 shown in FIG. 1, multi-sided vapor deposition of the organic EL display device 100 is possible. In some cases, one effective area 22 corresponds to a plurality of display areas.

As shown in FIG. 3, the effective region 22 has, for example, a substantially quadrangular contour in a plan view, or more accurately, a substantially rectangular contour in a plan view. Although not shown, each effective region 22 can have contours having various shapes depending on the shape of the display region of the organic EL substrate 92. For example, each effective region 22 may have a circular contour.

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

As shown in FIGS. 5 to 7, the plurality of through holes 25 were formed along the normal direction N of the vapor deposition mask 20 from the first surface 20a on one side along the normal direction N of the vapor deposition mask 20. It penetrates the second surface 20b on the other side. In the illustrated example, as will be described in detail later, the first recess 30 is formed by etching on the first surface 21a of the base material 21 which is one side in the normal direction N of the vapor deposition mask 20, and the vapor deposition mask 20 is formed. A second recess 35 is formed on the second surface 21b of the base material 21 on the other side in the normal direction N. The first recess 30 is connected to the second recess 35, whereby the second recess 35 and the first recess 30 are formed so as to communicate with each other. The through hole 25 is composed of a second recess 35 and a first recess 30 connected to the second recess 35.

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

As shown in FIGS. 5 to 7, the wall surface 31 of the first recess 30 and the wall surface 36 of the second recess 35 are connected via a circumferential connecting portion 41. In the connecting portion 41, the wall surface 31 of the first recess 30 inclined with respect to the normal direction N of the vapor deposition mask 20 and the wall surface 36 of the second recess 35 inclined with respect to the normal direction N of the vapor deposition mask 20 merge. It is defined by the ridgeline of the overhanging part.
Then, the connecting portion 41 defines the penetrating portion 42 in which the opening area of the through hole 25 is minimized in the plan view of the vapor deposition mask 20.

As shown in FIGS. 5 to 7, two adjacent through holes 25 are vapor-deposited on the other side surface of the vapor deposition mask 20 along the normal direction N, that is, on the first surface 20a of the vapor deposition mask 20. They are separated from each other along the plate surface of the mask 20. That is, as in the manufacturing method described later, when the base material 21 is etched from the first surface 21a side of the base material 21 corresponding to the first surface 20a of the vapor deposition mask 20 to produce the first recess 30. The first surface 21a of the base material 21 remains between the two adjacent first recesses 30.

Similarly, as shown in FIGS. 5 and 7, two adjacent second recesses are also formed on one side of the vapor deposition mask 20 along the normal direction N, that is, on the side of the second surface 20b of the vapor deposition mask 20. 35 may be separated from each other along the plate surface of the vapor deposition mask 20. That is, the second surface 21b of the base material 21 may remain between the two adjacent second recesses 35. In the following description, the portion of the effective region 22 of the second surface 21b of the base material 21 that remains unetched is also referred to as a top portion 43. By manufacturing the vapor deposition mask 20 so that such a top portion 43 remains, the vapor deposition mask 20 can be provided with sufficient strength. This makes it possible to prevent the vapor deposition mask 20 from being damaged during transportation, for example. If the width β of the top portion 43 is too large, shadows may occur in the vapor deposition process, which may reduce the utilization efficiency of the vapor deposition material 98. Therefore, it is preferable that the vapor deposition mask 20 is manufactured so that the width β of the top portion 43 does not become excessively large. For example, the width β of the top portion 43 is preferably 2 μm or less. The width β of the top portion 43 generally changes depending on the direction in which the vapor deposition mask 20 is cut. For example, the width β of the top portion 43 shown in FIGS. 5 and 7 may be different from each other. In this case, the vapor deposition mask 20 may be configured so that the width β of the top portion 43 is 2 μm or less when the vapor deposition mask 20 is cut in any direction.

As shown in FIG. 6, etching may be performed so that two adjacent second recesses 35 are connected depending on the location. That is, there may be a place where the second surface 21b of the base material 21 does not remain between the two adjacent second recesses 35. Further, although not shown, etching may be performed so that two adjacent second recesses 35 are connected over the entire area of the second surface 21b.

When the vapor deposition mask device 10 is housed in the vapor deposition device 90 as shown in FIG. 1, the first surface 20a of the vapor deposition mask 20 faces the organic EL substrate 92 as shown by the alternate long and short dash line in FIG. The second surface 20b of the vapor deposition mask 20 is located on the pot 94 side holding the vapor deposition material 98. Therefore, the thin-film deposition material 98 passes through the second recess 35 whose opening area is gradually reduced and adheres to the organic EL substrate 92. As shown by the arrow from the second surface 20b side to the first surface 20a in FIG. 5, the vapor deposition material 98 moves from the pot 94 toward the organic EL substrate 92 along the normal direction N of the organic EL substrate 92. Not only that, the organic EL substrate 92 may move in a direction greatly inclined with respect to the normal direction N. At this time, if the thickness of the vapor deposition mask 20 is large, the vapor deposition material 98 that moves diagonally is likely to be caught on the wall surface 36 of the top portion 43, the second recess 35, or the wall surface 31 of the first recess 30, and as a result, the through hole is formed. The proportion of the vapor-deposited material 98 that cannot pass through 25 increases. Therefore, in order to improve the utilization efficiency of the thin-film deposition material 98, the thickness t of the thin-film deposition mask 20 can be reduced, thereby reducing the height of the wall surface 36 of the second recess 35 and the wall surface 31 of the first recess 30. It is considered preferable. That is, it can be said that it is preferable to use the base material 21 having a thickness t as small as possible within the range in which the strength of the vapor deposition mask 20 can be secured as the base material 21 for forming the vapor deposition mask 20. In consideration of this point, in the present embodiment, the thickness t of the vapor deposition mask 20 is preferably set to 50 μm or less, for example, 5 μm or more and 50 μm or less. The thickness t is the thickness of the peripheral region 23, that is, the thickness of the portion of the vapor deposition mask 20 where the first recess 30 and the second recess 35 are not formed. Therefore, it can be said that the thickness t is the thickness of the base material 21.

In FIG. 5, a straight line L1 passing through the connecting portion 41, which is a portion having the minimum opening area of the through hole 25, and another arbitrary position of the wall surface 36 of the second recess 35, is in the normal direction of the vapor deposition mask 20. The minimum angle formed with respect to N is represented by the reference numeral θ1. In order for the thin-film deposition material 98 that moves diagonally to reach the organic EL substrate 92 as much as possible without reaching the wall surface 36, it is advantageous to increase the angle θ1. In order to increase the angle θ1, it is effective not only to reduce the thickness t of the vapor deposition mask 20 but also to reduce the width β of the top portion 43 described above.

In FIG. 7, reference numeral α represents the width of a portion (hereinafter, also referred to as a rib portion) of the effective region 22 of the first surface 21a of the base material 21 that remains unetched. The width α of the rib portion and the dimension r ₂ of the penetrating portion 42 are appropriately determined according to the dimensions of the organic EL display device and the number of display pixels. For example, the width α of the rib portion is 5 μm or more and 40 μm or less, and the dimension r ₂ of the penetrating portion 42 is 10 μm or more and 60 μm or less.

Although not limited, the vapor deposition mask 20 according to the present embodiment is particularly effective when producing an organic EL display device having a pixel density of 450 ppi or more. Hereinafter, with reference to FIG. 8, an example of the dimensions of the vapor deposition mask 20 required for manufacturing such an organic EL display device having a high pixel density will be described. FIG. 8 is an enlarged cross-sectional view showing a through hole 25 of the vapor deposition mask 20 shown in FIG. 5 and a region in the vicinity thereof.

In FIG. 8, as a parameter related to the shape of the through hole 25, the distance from the first surface 20a of the vapor deposition mask 20 to the connection portion 41 in the direction along the normal direction N of the vapor deposition mask 20, that is, the first recess. the height of the wall 31 of the 30 is represented by reference numeral _{r 1.} Furthermore, the first recess 30 dimensions of the first recess 30 in the portion connected to the second recess 35, i.e. the dimension of the through region 42 is represented by reference numeral r _2. Further, in FIG. 8, the angle formed by the straight line L2 connecting the connecting portion 41 and the tip edge of the first recess 30 on the first surface 21a of the base material 21 with respect to the normal direction N of the base material 21 is determined. It is represented by the reference numeral θ2.

When producing an organic EL display device having a pixel density of 450 ppi or more, the dimension r ₂ of the penetrating portion 42 is preferably set to 10 μm or more and 60 μm or less. This makes it possible to provide a thin-film deposition mask 20 capable of producing an organic EL display device having a high pixel density. _{Preferably, the height r 1} of the wall surface 31 of the first recess 30 is set to 6 μm or less.

Next, the above-mentioned angle θ2 shown in FIG. 8 will be described. The angle θ2 is a vapor deposition that can reach the organic EL substrate 92 among the vapor deposition materials 98 that are inclined with respect to the normal direction N of the base material 21 and that have flown so as to pass through the penetration portion 42 in the vicinity of the connection portion 41. It corresponds to the maximum value of the tilt angle of the material 98. This is because the thin-film deposition material 98 that has flown through the connecting portion 41 at an inclination angle larger than the angle θ2 adheres to the wall surface 31 of the first recess 30 before reaching the organic EL substrate 92. Therefore, by reducing the angle θ2, it is possible to prevent the thin-film deposition material 98 that flies at a large inclination angle and passes through the penetrating portion 42 from adhering to the organic EL substrate 92, thereby preventing the organic EL substrate 92 from adhering. It is possible to prevent the vapor-deposited material 98 from adhering to a portion outside the portion overlapping the penetrating portion 42. That is, reducing the angle θ2 leads to suppression of variations in the area and thickness of the vapor-deposited material 98 adhering to the organic EL substrate 92. From this point of view, for example, the through hole 25 is formed so that the angle θ2 is 45 degrees or less. In FIG. 8, the dimension of the first recess 30 on the first surface 21a, that is, the opening dimension of the through hole 25 on the first surface 21a is larger than the dimension r2 of the first recess 30 on the connecting portion 41. An example is shown. That is, an example is shown in which the value of the angle θ2 is a positive value. However, although not shown, the dimension r2 of the first recess 30 in the connecting portion 41 may be larger than the dimension of the first recess 30 in the first surface 21a. That is, the value of the angle θ2 may be a negative value.

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

Method for Manufacturing Metal Plate First, a method for manufacturing a metal plate used for manufacturing a vapor deposition mask will be described.

(Rolling process)
First, as shown in FIG. 9, a base material 60 composed of an iron alloy containing nickel is prepared, and the base material 60 is pointed at a rolling apparatus 66 including a pair of rolling rolls 66a and 66b, and is indicated by an arrow D1. Transport along the direction. The base metal 60 that has reached between the pair of rolling rolls 66a and 66b is rolled by the pair of rolling rolls 66a and 66b, and as a result, the base metal 60 is reduced in thickness and stretched along the transport direction. Is done. As a result, a metal plate 64 having a thickness of T0 can be obtained. As shown in FIG. 9, the winding body 62 may be formed by winding the metal plate 64 around the core 61. The thickness T0 is, for example, 10 μm or more and 50 μm or less.

Note that FIG. 9 merely shows an outline of the rolling process, and the specific configuration and procedure for carrying out the rolling process are not particularly limited. For example, the rolling process includes a hot rolling process in which the base metal is processed at a temperature equal to or higher than the temperature at which the crystal arrangement of the Inver material constituting the base material 60 is changed, and a base material at a temperature lower than the temperature at which the crystal arrangement of the Inver material is changed. It may include a cold rolling step of processing. Further, the direction in which the base metal 60 and the metal plate 64 are passed between the pair of rolling rolls 66a and 66b is not limited to one direction. For example, in FIGS. 9 and 10, the base metal 60 and the metal plate 64 are repeatedly passed between the pair of rolling rolls 66a and 66b in the direction from the left side to the right side of the paper surface and the direction from the right side to the left side of the paper surface. The base metal 60 and the metal plate 64 may be gradually rolled.

(Slit process)
After that, a slit step may be carried out in which both ends of the metal plate 64 obtained by the rolling step in the width direction are cut off over a predetermined range so that the width of the metal plate 64 is within a predetermined range. This slitting step is carried out to remove cracks that may occur at both ends of the metal plate 64 due to rolling. By carrying out such a slit process, it is possible to prevent a phenomenon in which the metal plate 64 is broken, that is, a so-called plate breakage, which occurs from the crack as a starting point.

(Annealing process)
Then, in order to remove the residual stress accumulated in the metal plate 64 by rolling, the metal plate 64 may be annealed using the annealing device 67 as shown in FIG. As shown in FIG. 10, the annealing step may be performed while pulling the metal plate 64 in the transport direction (longitudinal direction). That is, the annealing step may be carried out as continuous annealing while conveying, instead of so-called batch annealing.

Preferably, the annealing step described above is carried out in a non-reducing atmosphere or an inert gas atmosphere. Here, the non-reducing atmosphere is an atmosphere that does not contain a reducing gas such as hydrogen. "Does not contain reducing gas" means that the concentration of reducing gas such as hydrogen is 0.5% or less. The inert gas atmosphere is an atmosphere in which the concentration of the reducing gas is 0.5% or less and the concentration of the inert gas such as argon gas, helium gas, and nitrogen gas is 90% or more. By carrying out the annealing step in a non-reducing atmosphere or an inert gas atmosphere, it is possible to suppress the formation of nickel compounds such as nickel hydroxide on the surface layer of the metal plate 64.

By carrying out the annealing step, it is possible to obtain a metal plate 64 having a thickness T0 from which residual strain has been removed to some extent.

By repeating the above-mentioned rolling step, slitting step, and annealing step a plurality of times, a long metal plate 64 having a thickness T0 may be produced. Further, in FIG. 10, an example is shown in which the annealing step is carried out while pulling the metal plate 64 in the longitudinal direction, but the present invention is not limited to this, and the annealing step is carried out by winding the metal plate 64 around the core 61. It may be carried out in a state of being. That is, batch annealing may be carried out. When the annealing step is performed with the metal plate 64 wound around the core 61, the metal plate 64 may have a habit of warping according to the winding diameter of the wound body 62. Therefore, depending on the winding diameter of the winding body 62 and the material constituting the base material 60, it is advantageous to carry out the annealing step while pulling the metal plate 64 in the longitudinal direction.

(Cutting process)
After that, both ends of the metal plate 64 in the width direction are cut off over a predetermined range, thereby carrying out a cutting step of adjusting the width of the metal plate 64 to a desired width. In this way, a metal plate 64 having a desired thickness and width can be obtained.

By the way, as a result of diligent research by the present inventors, it was found that many inclusions are present in the surface layer of the rolled metal plate 64. FIG. 11 is a cross-sectional view showing how inclusions 64c are present in the surface layer of the metal plate 64 obtained by rolling. An inclusion is a granular substance composed of a compound containing a metal element other than iron such as aluminum and magnesium. The average particle size of the inclusions 64c is, for example, 0.5 μm or more and 20 μm or less. The average particle size of the inclusions 64c may be 0.5 μm or more and 10 μm or less, or 0.5 μm or more and 5 μm or less. Compounds include, for example, oxides, sulfides, carbides, nitrides, intermetallic compounds and the like.

As shown in FIG. 11, the inclusions 64c are abundantly present in the first surface layer on the first surface 64a side of the metal plate 64, which is located within the range represented by the reference numeral T1 in the thickness direction of the metal plate 64. Similarly, the inclusions 64c are also abundantly present in the second surface layer on the second surface 64b side of the metal plate 64, which is located within the range represented by the reference numeral T2 in the thickness direction of the metal plate 64. The first surface layer T1 is, for example, a portion within 5 μm in the thickness direction from the first surface 64a of the rolled metal plate 64. Further, the second surface layer T2 is, for example, a portion within 5 μm in the thickness direction from the second surface 64b of the rolled metal plate 64. Further, as shown in FIG. 11, the inclusions 64c are hardly present in the intermediate layer T3 located between the first surface layer T1 and the second surface layer T2.

FIG. 12 is a cross-sectional view showing a step of etching the metal plate 64 shown in FIG. 11 from the first surface 64a side to form the first recess 30. When the etching proceeds to the place where the inclusions 64c are present, the inclusions 64c are exposed on the wall surface 31 of the first recess 30 as shown in FIG. In the state shown in FIG. 12, most of the surface of the inclusions 64c exposed on the wall surface 31 is in contact with the iron alloy constituting the metal plate 64, so that the inclusions 64c are in contact with the wall surface 31. It is fixed.

FIG. 13 is a cross-sectional view showing a step of further proceeding etching from the state shown in FIG. 12 to enlarge the first recess 30. As the etching progresses, most of the surface of the inclusions 64c exposed on the wall surface 31 in FIG. 12 does not come into contact with the iron alloy constituting the metal plate 64. As a result, it is conceivable that the inclusions 64c are separated from the metal plate 64, and as shown in FIG. 13, the portion of the wall surface 31 where the inclusions 64c existed becomes the recessed portion 31a. Such a recess may also occur on the wall surface 36 of the second recess 35 formed on the second surface 64b side of the metal plate 64.

Etching proceeds faster in the recessed portion than in other portions. As a result, it is considered that the influence of the recessed portion appears on the shape of the above-mentioned through hole 25 composed of the first recessed portion 30 and the second recessed portion 35. FIG. 14 is a cross-sectional view showing an example of a vapor deposition mask 20 manufactured by using a metal plate 64 in which many inclusions 64c are present in the surface layers T1 and T2. As a result of intensive research by the present inventors, as shown in FIG. 14, the influence of the recessed portion formed by the detachment of the inclusions 64c is on the first surface 20a side of the second surface 20b side of the vapor deposition mask 20. I found that it appears a lot in. For example, as shown in FIG. 14, a recess 31a that reaches the first surface 20a of the vapor deposition mask 20 may be formed on the wall surface 31 of the first recess 30. Further, a chipped portion 41a may be formed in the connecting portion 41 due to the recessed portion.

The above-mentioned angle θ2 shown in FIG. 8 is determined by the position of the wall surface 31 of the first recess 30 and the position of the connecting portion 41 on the first surface 20a. As described above, the angle θ2 corresponds to the maximum value of the inclination angle in the flying direction of the vapor-deposited material 98 that can reach the organic EL substrate 92. Therefore, the recessed portion 31a and the chipped portion 41a shown in FIG. 14 cause variations in the range of the vapor deposition material 98 that can reach the organic EL substrate 92 in the flying direction. Therefore, if the recessed portion 31a or the chipped portion 41a is present in the through hole 25, it is considered that the dimensional accuracy and the position accuracy of the vapor-deposited material adhering to the organic EL substrate 92 through the through hole 25 are lowered. ..

In order to solve such a problem, in the present embodiment, the surface layer removal for removing the surface layer of the metal plate 64 is performed before the step of etching the metal plate 64 to form the through hole 25 in the metal plate 64. We propose to carry out the process. Thereby, the portion of the metal plate 64 in which a large amount of inclusions 64c are present can be removed. As a result, it is possible to prevent the shape of the through hole 25 from being varied due to the recessed portion formed by the detachment of the inclusions 64c. Hereinafter, a method for manufacturing a vapor deposition mask including a surface layer removing step will be described. In the following description, the metal plate from which the surface layer has been removed by carrying out the surface layer removing step is represented by reference numeral 64z.

Method for Manufacturing the Vapor Deposition Mask A method for manufacturing the vapor deposition mask 20 using the metal plate 64 will be described mainly with reference to FIGS. 15 to 25. FIG. 15 is a diagram showing a manufacturing apparatus 70 for manufacturing a vapor deposition mask 20 using a metal plate 64. First, a winding body 62 in which the metal plate 64 is wound around the core 61 is prepared. Then, by rotating the core 61 to unwind the winding body 62, the metal plate 64 extending in a strip shape is supplied as shown in FIG.

The supplied metal plate 64 is sequentially conveyed by the transfer roller 75 to the surface layer removing device 71, the processing device 72, and the separation device 73. The surface layer removing device 71 carries out a surface layer removing step of removing at least the first surface layer T1 on the first surface 64a side of the surface layer of the metal plate 64 obtained by rolling. The processing apparatus 72 performs a processing step of processing the metal plate 64z from which the surface layer has been removed to form a through hole 25 in the metal plate 64z. In the present embodiment, a large number of through holes 25 corresponding to the plurality of thin-film deposition masks 20 are formed in the metal plate 64z. In other words, a plurality of vapor deposition masks 20 are allocated to the metal plate 64z. The separation device 73 carries out a separation step of separating a portion of the metal plate 64z in which a plurality of through holes 25 corresponding to the vapor deposition mask 20 for one sheet are formed from the metal plate 64z. In this way, a single-wafer-shaped vapor deposition mask 20 can be obtained.

(Surface layer removal process)
First, the surface layer removing step will be described with reference to FIGS. 16 and 17. In the surface layer removing step, for example, as shown in FIG. 16, the injection device 71a injects the etching solution toward the first surface 64a of the metal plate 64, and the etching solution comes into contact with the first surface 64a of the metal plate 64. (Injection process). As the etching solution, for example, a ferric chloride solution can be used.
By carrying out such a wet etching step, as shown in FIG. 17, the first surface layer T1 can be removed over a predetermined range E1 in the thickness direction of the metal plate 64. The range E1 from which the first surface layer T1 is removed in the thickness direction is, for example, 0.5 μm or more and 20 μm or less, preferably 0.5 μm or more and 10 μm or less, and more preferably 0.5 μm or more and 5 μm or less. .. By appropriately setting the range E1, the first surface 64a of the metal plate 64z can be formed by the intermediate layer T3 in which the inclusions 64c are scarcely present. The thickness T4 of the metal plate 64z after the first surface layer T1 has been removed over a predetermined range is, for example, 5 μm or more and 50 μm or less.

By the way, when the etching solution is sprayed toward the first surface 64a with the first surface 64a of the metal plate 64 facing upward, the etching solution temporarily stays on the first surface 64a. As a result, it is conceivable that the etching proceeds excessively or the etching uniformity becomes low. In consideration of such a problem, preferably, as shown in FIG. 16, in the injection step, the etching solution is injected toward the first surface 64a with the first surface 64a of the metal plate 64 facing downward. In this case, the etching solution that adheres to the first surface 64a and dissolves the first surface layer T1 naturally falls or flows from the first surface 64a due to gravity. As a result, it is possible to prevent the etching solution from staying on the first surface 64a. Therefore, it is possible to prevent the first surface 64a of the metal plate 64 from being excessively etched, and it is possible to improve the uniformity of etching. Thereby, the thickness T4 of the metal plate 64z can be precisely controlled.

(Processing process)
Next, the processing step of forming the through hole 25 in the metal plate 64z will be described with reference to FIGS. 18 to 25. Note that in FIGS. 18 to 25, the inclusion 64c is not shown.

The steps of processing the metal plate 64z include a step of performing etching using a photolithography technique on the long metal plate 64z to form a first recess 30 on the metal plate 64z from the side of the first surface 64a, and a photo. It includes a step of applying etching using a lithography technique to a metal plate 64z to form a second recess 35 on the metal plate 64z from the side of the second surface 64b. Then, the first recess 30 and the second recess 35 formed in the metal plate 64z communicate with each other to form a through hole 25 in the metal plate 64z. In the example described below, the step of forming the first recess 30 is performed before the step of forming the second recess 35, and between the step of forming the first recess 30 and the step of forming the second recess 35, A step of sealing the produced first recess 30 is carried out. The details of each step will be described below.

First, as shown in FIG. 18, resist films 65c and 65d containing a negative photosensitive resist material are formed on the first surface 64a and the second surface 64b of the metal plate 64z. For example, a coating liquid containing a photosensitive resist material such as casein is applied onto the first surface 64a and the second surface 64b of the metal plate 64z, and then the coating liquid is dried to form resist films 65c and 65d. Form.

Next, exposure masks 68a and 68b are prepared so that light is not transmitted to the region of the resist films 65c and 65d to be removed, and the exposure masks 68a and 68b are used as the resist films 65c and 65d, respectively, as shown in FIG. Place on top. At this time, an alignment step for adjusting the relative positional relationship between the exposure mask 68a on the first surface 64a side and the exposure mask 68b on the second surface 64b side may be performed. As the exposure masks 68a and 68b, for example, a glass dry plate having a resist film 65c or 65d that does not allow light to pass through the region to be removed is used. Then, the exposure masks 68a and 68b are sufficiently adhered to the resist films 65c and 65d by vacuum adhesion.
As the photosensitive resist material, a positive type may be used. In this case, as the exposure mask, an exposure mask that allows light to pass through the region of the resist film to be removed is used.

Then, the resist films 65c and 65d are exposed through the exposure masks 68a and 68b (exposure step). Further, the resist films 65c and 65d are developed in order to form an image on the exposed resist films 65c and 65d (development step). As described above, as shown in FIG. 20, the first resist pattern 65a is formed on the first surface 64a of the metal plate 64z, and the second resist pattern 65b is formed on the second surface 64b of the metal plate 64z. be able to. The developing step may include a resist heat treatment step for increasing the hardness of the resist films 65c and 65d, or for making the resist films 65c and 65d more firmly adhere to the metal plate 64z.
The resist heat treatment step can be carried out, for example, at room temperature or higher and 400 ° C. or lower.

Next, as shown in FIG. 21, a first surface etching step is performed in which a region of the first surface 64a of the metal plate 64z that is not covered by the first resist pattern 65a is etched with the first etching solution. .. For example, the first etching solution is ejected from a nozzle arranged on the side of the conveyed metal plate 64z facing the first surface 64a toward the first surface 64a of the metal plate 64z through the first resist pattern 65a. .. As a result, as shown in FIG. 21, erosion by the first etching solution proceeds in the region of the metal plate 64z that is not covered by the first resist pattern 65a. As a result, a large number of first recesses 30 are formed on the first surface 64a of the metal plate 64z. As the first etching solution, for example, a solution containing ferric chloride solution and hydrochloric acid is used.

Then, as shown in FIG. 22, the first recess 30 is covered with the resin 69 having resistance to the second etching solution used in the subsequent second surface etching step. That is, the first recess 30 is sealed with the resin 69 having resistance to the second etching solution. In the example shown in FIG. 22, the film of the resin 69 is formed so as to cover not only the formed first recess 30 but also the first surface 64a (first resist pattern 65a).

Next, as shown in FIG. 23, a second surface of the second surface 64b of the metal plate 64z that is not covered by the second resist pattern 65b is etched to form a second recess 35 on the second surface 64b. Perform an etching process. The second surface etching step is carried out until the first recess 30 and the second recess 35 communicate with each other so that the through hole 25 is formed. As the second etching solution, for example, a solution containing ferric chloride solution and hydrochloric acid is used as in the case of the above-mentioned first etching solution.

The erosion by the second etching solution is performed in the portion of the metal plate 64z that is in contact with the second etching solution. Therefore, the erosion proceeds not only in the normal direction N (thickness direction) of the metal plate 64z, but also in the direction along the plate surface of the metal plate 64z. Here, preferably, in the second surface etching step, two second recesses 35 formed at positions facing two adjacent holes 66a of the second resist pattern 65b are located between the two holes 66a. It ends before merging on the back side of the bridge portion 67a. As a result, as shown in FIG. 24, the above-mentioned top portion 43 can be left on the second surface 64b of the metal plate 64z.

Then, as shown in FIG. 25, the resin 69 is removed from the metal plate 64z. The resin 69 can be removed by using, for example, an alkaline stripping solution. When an alkaline stripping solution is used, as shown in FIG. 25, the resist patterns 65a and 65b are removed at the same time as the resin 69. After removing the resin 69, the resist patterns 65a and 65b may be removed separately from the resin 69 by using a peeling liquid different from the peeling liquid for peeling the resin 69.

(Separation process)
After that, the vapor deposition mask 20 can be obtained by separating the portion of the metal plate 64z in which the plurality of through holes 25 corresponding to the vapor deposition mask 20 for one sheet are formed from the metal plate 64z.

(Action of the present embodiment)
In the method for manufacturing the vapor deposition mask 20 according to the present embodiment, the first surface layer T1 on the first surface 64a side of the metal plate 64 is formed before the metal plate 64 is processed to form the through hole 25 in the metal plate 64. Carry out a surface layer removal step to remove. As a result, it is possible to obtain a metal plate 64z in which the density of inclusions 64c on the first surface 64a side is reduced. As a result, it is possible to prevent the shape of the through hole 25 from being varied due to the recessed portion formed by the detachment of the inclusions 64c. Therefore, the dimensional accuracy and the position accuracy of the vapor-deposited material adhering to the organic EL substrate 92 through the through hole 25 can be improved.

It is possible to make various changes to the above-described embodiment. Hereinafter, a modified example will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment will be used for the parts that can be configured in the same manner as in the above-described embodiment. Duplicate explanations will be omitted. Further, when it is clear that the action and effect obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

(Deformation example of the surface layer to be removed)
In the above-described embodiment, only the first surface layer T1 on the first surface 64a side of the metal plate 64 is removed over the range E1 in the thickness direction, and the second surface layer T2 on the second surface 64b side is not removed. showed that. However, the present invention is not limited to this, and as shown in FIG. 26, in addition to the first surface layer T1, the second surface layer T2 on the second surface 64b side of the metal plate 64 is further added over the range E2 in the thickness direction. It may be removed. The range E2 from which the second surface layer T2 is removed in the thickness direction is, for example, 0.5 μm or more and 20 μm or less, preferably 0.5 μm or more and 10 μm or less, and more preferably 0.5 μm or more and 5 μm or less. .. The thickness T4 of the metal plate 64z after the first surface layer T1 and the second surface layer T2 have been removed over a predetermined range is, for example, 5 μm or more and 50 μm or less.

(Modified example of removal method)
In the above-described embodiment, an example of removing the surface layer of the metal plate 64 by injecting an etching solution toward the surface of the metal plate 64 has been shown, but the method of removing the surface layer is particularly limited. Absent. For example, the surface layer of the metal plate 64 may be removed by immersing the metal plate 64 in an etching tank in which the etching solution is stored. Further, the surface layer of the metal plate 64 may be removed by bringing a member such as a cloth impregnated with the etching solution into contact with the surface of the metal plate 64.

10 Thin film deposition mask device 15 Frame 20 Thin film deposition mask 21 Base material 22 Effective area 23 Peripheral area 25 Through hole 30 First recess 31 Wall surface 31a Depression 35 Second recess 36 Wall surface 41 Connection 41a Chip 43 Top 50 Intermediate product 64 Metal Plate 64c inclusions 64z metal plate 65a 1st resist pattern 65b 2nd resist pattern 65c 1st resist film 65d 2nd resist film 71 Surface layer removal device 72 Processing device 73 Separation device 90 Deposition device 92 Organic EL substrate 98 Deposition material

Claims (1)

A method for manufacturing a metal plate used for manufacturing a vapor deposition mask by forming a plurality of through holes.
A rolling process in which a base metal made of an iron alloy containing nickel is rolled to produce a metal plate containing a first surface and a second surface, and a rolling process.
A method for producing a metal plate, comprising: a surface layer removing step of removing at least the surface layer on the first surface side of the metal plate.

Images