Metal plate and evaporation mask including same

Abstract

A metal plate according to an embodiment includes a first region and a second region, the metal plate including invar containing iron and nickel, the thickness of the metal plate being 20 μm to 50 μm, the thickness of the second region being smaller than the thickness of the first region, the first region and the second region containing 40 wt % or less of nickel in a region from the surface of the metal plate to a depth of 2.5 μm, and the nickel content in the region from the first surface of the first region to a depth of 2.5 μm being smaller than the nickel content in the region from the second surface of the second region to a depth of 2.5 μm.

Description

[Technical Field]

[0001] The examples relate to a metal plate and a deposition mask including the same. [Background technology]

[0002] Display devices are used in a variety of devices. For example, display devices can be used in small devices such as smartphones and tablet PCs, as well as large devices such as televisions, monitors, and public displays (PDs). In particular, there has been an increasing demand for ultra-high resolution UHD (Ultra High Definition) with a resolution of 500 PPI (Pixels Per Inch) or more. This has led to growing interest in low power consumption and high resolution.

[0003] Commonly used display devices can be broadly classified into liquid crystal displays (LCDs) and organic light emitting diodes (OLEDs) depending on their driving methods.

[0004] An LCD is a display device driven by liquid crystal, and a light source such as a CCFL (Cold Cathode Fluorescent Lamp) or an LED (Light Emitting Diode) is disposed below the liquid crystal. The LCD adjusts the amount of light emitted from the light source using the liquid crystal.

[0005] OLEDs are display devices driven by organic materials. OLEDs do not require a separate light source. OLEDs can be driven with low power because the organic material acts as the light source. OLEDs can also display an infinite contrast ratio and have a response speed that is approximately 1,000 times faster than LCDs. OLEDs are also attracting attention as a display device that can replace LCDs due to their excellent viewing angle.

[0006] In OLEDs, the organic material contained in the light-emitting layer is deposited using a deposition mask called an open mask (OM) or fine metal mask (FMM). The deposited organic material is formed in a pattern corresponding to the pattern formed on the deposition mask. As a result, the deposited organic material acts as a pixel.

[0007] The open mask is a thin plate that allows deposition only in specific locations when manufacturing an OLED display. The open mask is used in the deposition process to form an emitting layer on the backplane after it has been completed during the display manufacturing process. That is, the open mask is an open mask that has no hidden areas within the display's operating range in order to deposit the front of the display. It is used to deposit an emitting layer with a single color emitting material, or to deposit layers such as EIL and HTL.

[0008] On the other hand, fine metal masks are used to change the color of the sub-pixels of the emitting layer to be realized, and for this purpose, ultra-fine holes are formed. The process using fine metal masks requires precise alignment as it requires several deposition steps, making it more difficult than a technology that uses only an open mask.

[0009] When an OLED display's emitting layer is deposited using an open mask, only one color can be emitted, so a separate layer such as a color filter (C / F) is required to realize the color. On the other hand, when an RGB emitting layer is formed using a fine metal mask, a separate color filter is not required. In other words, although the technology of using a fine metal mask for subpixels is difficult, it has better light efficiency than the method using an open mask because it does not require a filter to block light.

[0010] The fine metal mask is manufactured from an Invar alloy metal plate containing iron (Fe) and nickel (Ni). Through-holes are formed on one side and the other side of the metal plate, penetrating the one side and the other side, and the through-holes may be formed at positions corresponding to pixel patterns. Thus, organic materials such as red, green, and blue can be deposited on the substrate through the through-holes of the metal plate, forming pixel patterns on the substrate.

[0011] Meanwhile, before manufacturing the fine metal mask, a process of reducing the thickness of the metal plate and a process of polishing the surface of the metal plate may be performed.

[0012] The process may change the internal composition of the metal plate from region to region, for example, changing one region of the metal plate to one that is richer in nickel than iron.

[0013] This may change the etching characteristics of the metal plate, which may result in non-uniform sizes or shapes of through holes formed in the metal plate, which may result in a deterioration in the deposition quality of the deposition mask.

[0014] Therefore, there is a need for a metal plate and a deposition mask that can solve the above problems.

[0015] Korean Patent Publication KR10-2020-0058072 (May 27, 2020) discloses a technique related to the deposition mask. Summary of the Invention [Problem to be solved by the invention]

[0016] The embodiments seek to provide metal sheets having a uniform composition.

[0017] The embodiments seek to provide a metal plate with improved deposition efficiency. [Means for solving the problem]

[0018] A metal plate according to an embodiment includes a first region and a second region, the metal plate including invar containing iron and nickel, the thickness of the metal plate being 20 μm to 50 μm, the thickness of the second region being smaller than the thickness of the first region, the first region and the second region containing 40 wt % or less of nickel in a region from the surface of the metal plate to a depth of 2.5 μm, and the nickel content in the region from the first surface of the first region to a depth of 2.5 μm being smaller than the nickel content in the region from the second surface of the second region to a depth of 2.5 μm.

[0019] The metal plate according to the embodiment includes invar containing iron and nickel, the thickness of the metal plate is 20 μm to 30 μm, the metal plate contains 40 wt % or less of nickel in a region from the surface of the metal plate to a depth of 2.5 μm, and the metal plate has a nickel weight deviation of 1 wt % to 6 wt % in a region from the surface of the metal plate to a depth of 2.5 μm. [Effects of the Invention]

[0020] The metal plate according to the embodiment can have improved surface properties.

[0021] In particular, the metal plate according to the embodiment may have a small surface roughness and a small thickness deviation.

[0022] In the metal plate according to the embodiment, the surface of the metal plate can be polished after the cold rolling process and before the through holes are formed in the metal plate, so that the nickel content in the region from the surface to a set depth range of the metal plate can be 40 wt % or less.

[0023] Therefore, it is possible to prevent the etching characteristics of the metal plate from changing due to the different nickel contents in different regions on the surface of the metal plate, and thus, when the thickness of the metal plate is further reduced, it is possible to improve the thickness uniformity of the final metal plate.

[0024] Furthermore, when through holes are formed in the metal plate, the shapes and sizes of the through holes can be made uniform.

[0025] As a result, the deposition mask manufactured using the metal plate can have improved deposition reliability. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a diagram illustrating the surface of the metal plate according to the example after the first surface treatment step. [Figure 2] FIG. 2 is a diagram illustrating the surface of a metal plate according to an embodiment after a cold rolling process. [Figure 3] FIG. 2 is a diagram illustrating the surface of a metal plate according to an embodiment after a cold rolling process. [Figure 4] FIG. 2 is a diagram illustrating the region of the metal plate after the cold rolling process. [Figure 5] FIG. 10 is a diagram for explaining a step of checking the surface of the metal plate after the cold rolling step. [Figure 6] FIG. 10 is a diagram for explaining a step of checking the surface of the metal plate after the cold rolling step. [Figure 7] FIG. 10 is a diagram for explaining a step of checking the surface of the metal plate after the cold rolling step. [Figure 8] FIG. 10 is a view for explaining a second surface treatment step. [Figure 9] FIG. 10 is a diagram illustrating a metal plate manufactured by the second surface treatment step. [Figure 10] FIG. 10 is a diagram illustrating a metal plate manufactured by the second surface treatment step. [Figure 11] 1 is a diagram illustrating the characteristics of metal plates according to an example and a comparative example. FIG. [Figure 12] 1 is a diagram illustrating the characteristics of metal plates according to an example and a comparative example. FIG. [Figure 13] 1 is a diagram illustrating the characteristics of metal plates according to an example and a comparative example. FIG. [Figure 14] 1 is a diagram illustrating the characteristics of metal plates according to an example and a comparative example. FIG. [Figure 15] 1 is a diagram illustrating the characteristics of metal plates according to an example and a comparative example. FIG. [Figure 16] 10A and 10B are diagrams illustrating a deposition mask coupled to a frame according to an embodiment of the present invention. [Figure 17] FIG. 1 is a cross-sectional view showing an organic material vapor deposition apparatus including a vapor deposition mask according to an embodiment. [Figure 18] 1A to 1C are diagrams illustrating the formation of a deposition pattern on a deposition substrate using the deposition mask according to the embodiment. [Figure 19] FIG. 1 is a plan view of an evaporation mask according to an embodiment. [Figure 20] 10A and 10B are diagrams for explaining defects in through holes in the evaporation mask according to the example. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical concept of the present invention is not limited to some of the described embodiments, and may be embodied in various different forms, and one or more of the components of the embodiments may be selectively combined or substituted within the scope of the technical concept of the present invention. Furthermore, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having meanings that are commonly understood by those skilled in the art to which the present invention belongs, unless otherwise clearly defined and described. Commonly used terms, such as predefined terms, may be interpreted in light of the context of the relevant art.

[0028] Furthermore, the terms used in the examples of the present invention are intended to describe the examples and do not limit the present invention. In this specification, the singular form can include the plural form unless otherwise specified in the phrase, and when referring to "A and (and) at least one (or more) of B and C," it can include one or more of all combinations that can be combined with A, B, and C.

[0029] Furthermore, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. are used merely to distinguish the component from other components, and the terms do not limit the essence, order, or sequence of the components.

[0030] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it can include not only cases where the component is directly coupled, coupled, or connected to the other component, but also cases where the component is "coupled," "coupled," or "connected" by another component between the component and the other component.

[0031] Furthermore, when it is stated that a component is formed or disposed "above or below" each component, "above" or "below" includes not only the case where the two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components.

[0032] In addition, when expressed as "upper" or "lower," it can mean not only the upper direction but also the lower direction based on one component.

[0033] The deposition mask described below is a fine metal mask (FMM) that can form an RGB pixel pattern on a deposition substrate by depositing red, green, and blue organic materials on the deposition substrate. The following description does not apply to an open mask (OM).

[0034] In the following description, the first direction 1D is defined as the longitudinal direction of the metal plate or the deposition mask, and the second direction 2D is defined as the width direction of the metal plate or the deposition mask.

[0035] Hereinafter, a metal plate and a deposition mask including the same according to an embodiment will be described with reference to the drawings.

[0036] First, a metal plate according to an embodiment will be described with reference to FIGS.

[0037] Metal plate and its manufacturing method

[0038] The metal plate 10 according to the embodiment described below may be a raw material for manufacturing a deposition mask. For example, the deposition mask described below may be formed by forming a plurality of through holes in the metal plate 10.

[0039] The metal plate 10 may include an alloy. Specifically, the metal plate 10 may include iron (Fe) and nickel (Ni). More specifically, the metal plate may include iron (Fe), nickel (Ni), oxygen (O), and chromium (Cr). The metal plate may further include a small amount of at least one element selected from the group consisting of carbon (C), silicon (Si), sulfur (S), phosphorus (P), manganese (Mn), titanium (Ti), cobalt (Co), copper (Cu), silver (Ag), vanadium (V), niobium (Nb), indium (In), and antimony (Sb). In one example, the metal plate 10 may include an Invar alloy.

[0040] Invar is an alloy containing iron and nickel. Invar is a low-thermal expansion alloy with a thermal expansion coefficient close to zero. Invar has an extremely low thermal expansion coefficient. As a result, Invar is used in precision parts and precision instruments such as masks. Therefore, when a deposition mask is manufactured using the metal plate 10, deformation of the deposition mask can be prevented, thereby increasing the mask's lifespan.

[0041] The metal plate 10 may include Invar containing 60 to 65% by weight of iron and 35 to 40% by weight of nickel. The metal plate 10 may further include 1% by weight or less of at least one element selected from the group consisting of carbon (C), silicon (Si), sulfur (S), phosphorus (P), manganese (Mn), titanium (Ti), cobalt (Co), copper (Cu), silver (Ag), vanadium (V), niobium (Nb), indium (In), and antimony (Sb).

[0042] The components, content, and weight percentage of the metal plate can be determined by selecting any sample area on the plane of the metal plate 10 and sampling a test piece corresponding to the thickness of the metal plate 10. The test piece can then be dissolved in a strong acid or the like to determine the weight percentage of each component. However, the embodiments are not limited thereto, and the components and weight percentage of the metal plate can be determined by various methods that can determine the composition of the metal plate.

[0043] The metal plate 10 may be subjected to a pre-treatment process before the through holes are formed. Specifically, the pre-treatment process may be performed to reduce the thickness of the metal plate 10. Also, the pre-treatment process may be performed to improve the surface characteristics of the metal plate 10.

[0044] The pretreatment process can reduce the thickness of the metal plate 10. Also, the pretreatment process can reduce the surface roughness of the metal plate 10. Also, the pretreatment process can change the surface composition of the metal plate 10. As a result, the metal plate can have a thin thickness and improved surface properties.

[0045] For example, the pretreatment step may include a thickness control step and a surface treatment step, a hot rolling step and a cold rolling step, or a hot rolling step, a cold rolling step, and an etching step.

[0046] The surface treatment step includes a first surface treatment step and a second surface treatment step, and the surface treatment step can be performed together with the thickness control step.

[0047] For example, the hot rolling step, the first surface treatment step, the cold rolling step, and the second surface treatment step may be performed in this order.

[0048] Alternatively, the hot rolling step, the first surface treatment step, the cold rolling step, the second surface treatment step, and the etching step may be performed in this order.

[0049] The method for manufacturing the metal plate will now be described.

[0050] First, the hot rolling process is performed. The hot rolling process reduces the thickness of the metal plate 10. For example, the thickness of the metal plate 10 is reduced from a thickness exceeding 3 mm to a thickness of 3 mm or less.

[0051] Subsequently, the first surface treatment step is carried out.

[0052] The first surface treatment process is performed to remove surface inclusions from the metal plate 10, thereby improving the surface characteristics of the metal plate 10. The first surface treatment process may be performed by mechanical polishing using a device such as a grinder. At this time, scratches or burrs may be formed on the surface S of the metal plate 10 due to the first surface treatment process. Alternatively, by-products such as particles may be generated during the first surface treatment process, and the by-products may adhere to the surface of the metal plate 10.

[0053] For example, referring to Fig. 1, a recessed area SA1 may be formed on the surface S of the metal plate where the surface S of the metal plate is partially removed by scratches. Alternatively, an area SA2 may be formed on the surface S of the metal plate where burrs have formed, and an area SA3 may be formed on the surface S of the metal plate where the by-products are attached.

[0054] Therefore, a plurality of protruding regions PA1 may be formed on the metal plate 10 by the recessed regions SA1, the raised regions SA2, and the regions SA3 to which by-products adhere.

[0055] Subsequently, the cold rolling step is performed. The thickness of the metal plate 10 is reduced by the cold rolling step. For example, the thickness of the metal plate 10 after the cold rolling is reduced to a thickness of 50 μm or less. Specifically, the thickness of the metal plate 10 after the cold rolling is reduced to a thickness of 40 μm to 50 μm.

[0056] When the metal plate 10 including the protruding regions PA1 is cold-rolled, the protruding regions PA1 may be pressed onto the surface S of the metal plate 10 by pressure. As a result, referring to FIG. 2, a plurality of pressing regions PA2 to which the protruding regions PA1 are pressed may be formed on the surface S of the metal plate 10.

[0057] Fig. 3 is a diagram illustrating the surface of the metal plate 10. Fig. 3(a) is a photograph of the metal plate 10 after cold rolling taken with an optical microscope. Fig. 3(b) is a photograph of the metal plate 10 after cold rolling analyzed with a scanning electron microscope (SEM).

[0058] 3, the pressure-bonding area PA2 may deteriorate the surface characteristics of the metal plate, for example, the pressure-bonding area PA2 may cause the surface thickness of the metal plate to become non-uniform and increase the surface roughness of the metal plate.

[0059] The pressure-bonded region PA2 may have a higher nickel (Ni) content than other regions. Specifically, the pressure-bonded region PA2 may have a higher nickel content than regions excluding the pressure-bonded region PA2. Specifically, a nickel (Ni)-enriched layer is formed in the pressure-bonded region PA2 according to the following reaction formula, thereby increasing the nickel content:

[0060] [Reaction scheme]

[0061] 4FeO->Fe3O4+Fe

[0062] NiO+Fe->FeO+Ni

[0063] Thus, referring to FIG. 4, the metal plate 10 after the cold rolling can include a first surface region 1SA and a second surface region 2SA.

[0064] The first surface region 1SA may be defined as a region having a low nickel content. Specifically, the first surface region 1SA may be defined as a region having a nickel content of 40% by weight or less. The first surface region 1SA may also be defined as a region having an iron (Fe) content of 60% by weight or more.

[0065] The second surface region 2SA may be defined as a region having a high nickel content. Specifically, the second surface region 2SA may be defined as a region having a nickel content of more than 40% by weight. The second surface region 2SA may also be defined as a region having an iron (Fe) content of less than 60% by weight. The second surface region 2SA may have a higher nickel content than the first surface region 1SA due to the crimped region PA2.

[0066] Therefore, when performing a process of forming through holes in the metal plate after the cold rolling process, a difference in etching rate may occur between the first surface region 1SA and the second surface region 2SA. Specifically, the first surface region 1SA may have a high iron content and a low nickel content, and therefore the etching rate may be fast. However, the second surface region 2SA may have a low iron content and a high nickel content, and therefore the etching rate may be slow.

[0067] Therefore, when forming through holes in the metal plate 10, the amount of etching varies depending on the region of the metal plate, which can cause defects in the through holes.

[0068] Alternatively, when etching the metal plate 10 to further reduce its thickness, the amount of etching may vary depending on the region of the metal plate. Thus, the thickness of the second surface region 2SA may be greater than the thickness of the first surface region 1SA. As a result, when forming through holes in the metal plate 10, etching uniformity may be reduced due to differences in the thickness of the metal plate. Therefore, the shape or size of the through holes in the deposition mask may become non-uniform. This may reduce the deposition efficiency of the deposition mask.

[0069] 5 to 7 are diagrams for explaining changes in the surface of the metal sheet after the cold rolling process.

[0070] 5, a cold-rolled metal plate 10 is prepared, and then the metal plate 10 is etched to a thickness t within a set range.

[0071] 6 is a photograph of the cold-rolled metal plate 10 after etching. FIG. 7 is a scanning electron microscope (SEM) photograph of region A in FIG.

[0072] Referring to Figure 6, a linear pattern or a dot-shaped pattern can be seen on the metal plate 10. The pattern PA is formed by a nickel-enriched layer. That is, after the cold rolling process, a nickel-rich region is formed on the surface of the metal plate 10. That is, after the cold rolling process, a nickel-rich region is formed on the metal plate 10.

[0073] 7, the pattern PA includes a plurality of protrusions P. The protrusions P are formed in a linear or dotted shape. The composition ratio of the region where the protrusions P are formed is different from the composition ratio of the other regions. Specifically, the region where the protrusions P are formed has a higher nickel content than the other regions.

[0074] That is, the metal plate 10 has a nickel-rich region formed after the cold rolling process.

[0075] In order to solve the above-mentioned problems, the metal sheet according to the embodiment may further undergo a second surface treatment process after the cold rolling process.

[0076] In the second surface treatment step, the metal plate 10 may be polished. Specifically, the entire surface of the metal plate 10 may be polished. For example, the metal plate may be polished by mechanical polishing or chemical polishing.

[0077] Specifically, in the second surface treatment step, the surface of the metal plate 10 can be polished to a thickness of 0.4 μm or less. For example, the surface of the metal plate 10 can be polished to a thickness of 0.2 μm to 0.4 μm.

[0078] The second surface treatment step can remove the nickel-enriched layer.

[0079] 8, the protrusion P may be removed. Specifically, the nickel-enriched layer of the metal plate 10 may be removed.

[0080] Therefore, the composition ratio becomes uniform over the entire surface of the metal plate 10. This can improve the surface characteristics of the metal plate 10.

[0081] The second surface treatment step performed after the cold rolling step allows the metal plate 10 to have improved surface properties.

[0082] Subsequently, an etching process is performed. In the etching process, the entire surface of the metal plate 10 is etched. The thickness of the metal plate 10 is reduced by the etching process. Specifically, the thickness of the metal plate is reduced to 30 μm or less by the etching process. More specifically, the thickness of the metal plate is reduced to 20 μm to 30 μm by the etching process.

[0083] The etching process may be omitted. Specifically, the thickness of the metal plate 10 may be reduced in the second surface treatment process. For example, the thickness of the metal plate 10 may be reduced to 20 μm to 30 μm by the second surface treatment process.

[0084] The metal plate according to the embodiment has improved surface properties. Specifically, the protrusions are removed by the second surface treatment process. This allows the surface composition of the metal plate to be uniform, and the surface roughness of the metal plate to be uniform.

[0085] This allows the through holes to be formed in the metal plate with a uniform size or shape.

[0086] Furthermore, when the metal plate is further etched, the thickness of the metal plate can be uniformly etched, and the surface composition and surface roughness of the metal plate after the etching process can be uniform.

[0087] FIG. 9 is a cross-sectional view of a metal plate manufactured by a process that omits the etching process.

[0088] 9, when a metal plate is manufactured by the above process, the metal plate may include a first region 1A and a second region 2A. The second region 2A is defined as a region where the nickel-enriched layer has been removed through the second surface treatment process.

[0089] After the second surface treatment step, the thickness of the metal plate 10 may be 20 μm to 50 μm. The surface of the metal plate 10 may be divided into two surfaces. For example, the first region 1A may have a first surface S1, and the second region 2A may have a second surface S2.

[0090] The first region 1A and the second region 2A may have different thicknesses. Specifically, the thickness T1 of the first region 1A may be greater than the thickness T2 of the second region 2A. For example, the difference D between the thickness T1 of the first region 1A and the thickness T2 of the second region 2A may be greater than 0 μm and up to 0.5 μm.

[0091] The nickel content in the region from the first surface S1 to a depth of 2.5 μm may be 40 wt % or less, and the nickel content in the region from the second surface S2 to a depth of 2.5 μm may be 40 wt % or less.

[0092] The first region 1A and the second region 2A may have different composition ratios. Specifically, the first region 1A and the second region 2A may have different nickel contents. Furthermore, the first region 1A and the second region 2A may have different iron contents.

[0093] Specifically, the nickel content in the region from the first surface S1 to a depth of 2.5 μm may be lower than the nickel content in the region from the second surface S2 to a depth of 2.5 μm. For example, the difference between the nickel content in the region from the first surface S1 to a depth of 2.5 μm and the nickel content in the region from the second surface S2 to a depth of 2.5 μm may be 6 wt % or less, 4 wt % or less, or 2 wt % or less. Specifically, the difference between the nickel content in the region from the first surface S1 to a depth of 2.5 μm and the nickel content in the region from the second surface S2 to a depth of 2.5 μm may be 1 wt % to 6 wt %.

[0094] Furthermore, the iron content in the region from the first surface S1 to a depth of 2.5 μm may be greater than the iron content in the region from the second surface S2 to a depth of 2.5 μm. For example, the difference between the iron content in the region from the first surface S1 to a depth of 2.5 μm and the iron content in the region from the second surface S2 to a depth of 2.5 μm may be 6 wt % or less, 4 wt % or less, or 2 wt % or less. In particular, the difference between the iron content in the region from the first surface S1 to a depth of 2.5 μm and the iron content in the region from the second surface S2 to a depth of 2.5 μm may be 1 wt % to 6 wt %.

[0095] The second region 2A is a region from which the nickel-enriched layer has been removed, and the remaining nickel-enriched layer may have a high nickel content and a low iron content.

[0096] The nickel content and the deviation of the nickel content in the region from the surface S of the metal plate to a depth of 2.5 μm can be controlled.

[0097] This allows the surface composition to be uniform across the entire area of ​​the metal plate. That is, the difference in nickel weight percentage and iron weight percentage in the area from the surface to a depth of 2.5 μm of the metal plate is reduced. This reduces the difference in etching rate due to the difference in nickel weight percentage and iron weight percentage when forming through holes in the metal plate. Therefore, it is possible to reduce the deviation in the shape and size of the through holes formed in the metal plate.

[0098] The first region 1A and the second region 2A may have different surface roughnesses. Specifically, the first surface S1 and the second surface S2 may have different roughnesses. Specifically, the surface roughness of the second region may be smaller than the surface roughness of the first region. The second region 2A is a region from which a nickel-enriched layer is removed by polishing. As a result, the surface roughness of the second region 2A may be smaller than that of the first region 1A.

[0099] FIG. 10 is a cross-sectional view of a metal plate manufactured by carrying out the etching step after the second surface treatment step.

[0100] After the etching process, the thickness of the metal plate 10 may be 20 μm to 30 μm.

[0101] The metal plate 10 may contain nickel and iron in a range of set weight percent in a region from the surface S of the metal plate 10 to a depth of 2.5 μm.

[0102] Specifically, the nickel content in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 40% by weight or less. Furthermore, the difference in nickel content in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 6% by weight or less, 4% by weight or less, or 2% by weight or less. For example, the difference in nickel content in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 1% by weight to 6% by weight.

[0103] The iron content in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 60% by weight or more. Specifically, the iron content in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 60% by weight to 64% by weight. The difference in iron content in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 6% by weight or less, 4% by weight or less, or 2% by weight or less. For example, the difference in iron content in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 1% by weight to 6% by weight.

[0104] Any two sample areas can be selected from the surface S of the metal plate 10. The difference between the nickel weight % and the iron weight % measured in the area from the surface to a depth of 2.5 μm in each sample area can have a set range.

[0105] Specifically, the difference in nickel weight percent measured in the region from the surface to a depth of 2.5 μm of each sample region may be 6 wt% or less, 4 wt% or less, or 2 wt% or less. For example, the difference in nickel weight percent measured in the region from the surface to a depth of 2.5 μm of each sample region may be 1 wt% to 6 wt%.

[0106] The difference in iron weight percentage measured in the region from the surface of each sample area to a depth of 2.5 μm may be 6% by weight or less, 4% by weight or less, or 2% by weight or less. For example, the difference in iron weight percentage measured in the region from the surface of each sample area to a depth of 2.5 μm may be 1% to 6% by weight.

[0107] Alternatively, the metal plate 10 may have an average nickel weight % and an average iron weight % within a set range in a region from the surface S of the metal plate 10 to a depth of 2.5 μm. The average nickel weight % may be defined as a value obtained by selecting n sample regions on the surface S of the metal plate 10 and dividing the sum of the nickel weight % measured in each sample region by n. Also, the average iron weight % may be defined as a value obtained by selecting n sample regions on the surface S of the metal plate 10 and dividing the sum of the iron weight % measured in each sample region by n.

[0108] The average nickel weight % in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 36% to 40% by weight, and the average iron weight % in the region from the surface S of the metal plate 10 to a depth of 2.5 μm may be 60% to 64% by weight.

[0109] The metal plate 10 may have a surface roughness within a set range. Specifically, the metal plate 10 may include a first surface 1S and a second surface 2S opposite to the first surface 1S. The first surface 1S may be defined as the surface of the metal plate 10 that is to be surface-treated.

[0110] The first surface 1S and the second surface 2S may have different surface roughnesses. Specifically, the surface roughness of the first surface 1S may be smaller than the surface roughness of the second surface 2S. For example, the minimum arithmetic mean roughness Ra of the first surface 1S may be 30 nm to 59 nm. Furthermore, the minimum ten-point mean roughness Rz of the first surface 1S may be 0.5 nm to 0.79 nm.

[0111] The metal plate may have a thickness deviation within a set range, which may be defined as the ratio between the maximum and minimum values ​​of the metal plate. The metal plate may have a thickness deviation of 3% or less in the first and second directions.

[0112] The metal plate 10 can have low surface roughness and improved thickness uniformity because the metal plate can be etched to a uniform thickness through the second surface treatment process.

[0113] The metal plate 10 may contain nickel and iron within a set range in a region from the surface of the metal plate to a depth of 2.5 μm. The metal plate 10 may also have a nickel weight percentage deviation and an iron weight percentage deviation within a set range in a region from the surface of the metal plate to a depth of 2.5 μm.

[0114] This allows the surface composition of the metal plate to be uniform throughout the entire area. That is, the difference in weight percentage between nickel and iron in the area from the surface of the metal plate to a depth of 2.5 μm can be reduced. This reduces the difference in etching rate due to the difference in weight percentage between nickel and iron when forming through holes in the metal plate. Therefore, it is possible to reduce deviations in the shape and size of through holes formed in the metal plate.

[0115] The present invention will be described in more detail below through examples and comparative examples.

[0116] Example 1

[0117] An Invar metal plate having a thickness of 3 mm was produced.

[0118] Subsequently, a hot rolling step, a first surface treatment step, a cold rolling step, and a second surface treatment step were carried out in this order, thereby producing a metal plate having a thickness of 40 μm.

[0119] In this case, the first surface treatment step involved polishing the surface of the metal plate using a grinder.

[0120] In the second surface treatment step, chemical polishing or mechanical polishing was performed.

[0121] Subsequently, a test piece was sampled from an arbitrary region of the metal plate, and the test piece was dissolved in strong acid to measure the nickel and iron contents of the metal plate.

[0122] Example 2

[0123] After the second surface treatment process, the metal plate was further etched to produce a metal plate having a thickness of 20 μm, in the same manner as in Example 1.

[0124] Subsequently, a test piece was sampled from an arbitrary region of the metal plate, and the test piece was dissolved in strong acid to measure the nickel and iron contents of the metal plate.

[0125] Comparative Example 1

[0126] A metal plate was manufactured in the same manner as in Example 1, except that the second surface treatment process was not performed.

[0127] Subsequently, the pattern area was sampled as a test piece, and the test piece was dissolved in strong acid to measure the nickel and iron contents of the metal plate.

[0128] Comparative Example 2

[0129] A metal plate was manufactured in the same manner as in Example 2, except that the second surface treatment process was not performed.

[0130] Subsequently, a test piece was sampled from an arbitrary region of the metal plate, and the test piece was dissolved in strong acid to measure the nickel and iron contents of the metal plate.

[0131] Fig. 11 is a graph showing the iron and nickel contents of the metal plates according to Examples 1 and 2. Fig. 12 is a graph showing the iron and nickel contents of the metal plates according to Comparative Examples 1 and 2.

[0132] Referring to FIG. 11, in the metal plate according to the example, the nickel content is 40 wt % or less and the iron content is 60 wt % in a region from the surface to a depth of 2.5 μm.

[0133] On the other hand, referring to FIG. 12, the metal plate according to the comparative example includes a region in the region from the surface to a depth of 2.5 μm where the nickel content exceeds 40 wt % and the iron content is less than 60 wt %.

[0134] The metal plate according to the embodiment undergoes a second surface treatment process to remove the nickel-rich region, so that the nickel content of the metal plate according to the embodiment can be 40 wt % or less and the iron content can be 60 wt % in the region from the surface to a depth of 2.5 μm.

[0135] On the other hand, the metal sheet according to the comparative example does not undergo the second surface treatment step of removing the nickel-rich region, and as a result, the metal sheet according to the comparative example includes a region in which the nickel content exceeds 40 wt % and the iron content is less than 60 wt % in a region up to a depth of 2.5 μm from the surface due to the nickel-enriched layer.

[0136] This allows the Examples and Comparative Examples to have different surface properties. Figures 13 to 15 are diagrams showing surface photographs of the metal plates according to the Examples and Comparative Examples. Figures 13, 14, and 15(a) are surface photographs of the metal plate according to the Comparative Example, and Figures 13, 14, and 15(b) are surface photographs of the metal plate according to the Examples.

[0137] 13 to 15, the metal plate according to the comparative example may have high surface roughness due to the protrusions formed by the nickel-enriched layer, and may also have low thickness uniformity due to the protrusions formed by the nickel-enriched layer.

[0138] On the other hand, the metal plate according to the embodiment has a small surface roughness and can improve thickness uniformity because the nickel-enriched layer is removed.

[0139] evaporation mask

[0140] Hereinafter, evaporation masks according to examples will be described with reference to FIGS.

[0141] 16 and 17, the organic vapor deposition apparatus includes a vapor deposition mask 100, a mask frame 200, a vapor deposition substrate 300, an organic vapor deposition container 400, and a vacuum chamber 500.

[0142] The deposition mask 100 may be formed using the above-described metal plate 10. The deposition mask 100 includes a plurality of through holes TH formed in an effective portion for deposition. At this time, the through holes are formed to correspond to a pattern to be formed on a deposition substrate. That is, the deposition mask 100 includes a metal plate 10, and a plurality of through holes TH may be formed in the metal plate 10.

[0143] The mask frame 200 includes openings 205. A plurality of through holes of the deposition mask 100 are disposed in regions corresponding to the openings 205 of the mask frame 200. Thus, the organic material supplied to the organic material deposition container 400 is deposited on the deposition substrate 300. The deposition mask 100 is disposed and fixed on the mask frame 200. For example, the deposition mask 100 may be stretched with a set amount of tension and welded to the mask frame 200 to be fixed.

[0144] For example, the deposition mask 100 may be fixed to the mask frame 200 by welding a non-deposition area of ​​the deposition mask 100. Then, a portion of the deposition mask 100 disposed outside the mask frame 200 is removed by a method such as cutting.

[0145] The mask frame 200 is made of a material that is less likely to deform when the deposition mask 100 is welded thereto, such as a metal with high rigidity.

[0146] The deposition substrate 300 is a substrate used in manufacturing a display device. For example, the deposition substrate 300 may be a substrate for depositing organic materials for an OLED pixel pattern. On the deposition substrate 300, red, green, and blue organic material patterns are formed to form pixels of the three primary colors of light. That is, an RGB pattern may be formed on the deposition substrate 300.

[0147] The organic material deposition container 400 is a crucible. An organic material is placed inside the crucible. The organic material deposition container 400 moves within the vacuum chamber 500. That is, the organic material deposition container 400 moves in one direction within the vacuum chamber 500. For example, the organic material deposition container 400 moves within the vacuum chamber 500 in the width direction of the deposition mask 100. That is, the organic material deposition container 400 moves within the vacuum chamber 500 in a direction perpendicular to the length direction of the deposition mask 100.

[0148] The organic material is deposited on the deposition substrate 300 by supplying a heat source and / or an electric current to the crucible serving as the organic material deposition vessel 400 in the vacuum chamber 500 .

[0149] Referring to FIG. 18, the deposition mask 100 includes a first surface 1S and a second surface 2S opposite to the first surface 1S.

[0150] The first surface 1S includes a small surface hole V1, and the second surface 2S includes a large surface hole V2. For example, each of the first surface 1S and the second surface 2S includes a plurality of small surface holes V1 and a plurality of large surface holes V2.

[0151] The deposition mask 100 also includes through holes TH. The through holes TH are communicated with each other by a communication portion CA that connects the boundaries of the small surface holes V1 and the large surface holes V2.

[0152] The width of the large-surface hole V2 is larger than the width of the small-surface hole V1. At this time, the width of the small-surface hole V1 is measured on the first surface 1S of the deposition mask 100, and the width of the large-surface hole V2 is measured on the second surface 2S of the deposition mask 100.

[0153] Furthermore, the width of the communicating portion CA has a set size. Specifically, the width of the communicating portion CA may be 15 μm to about 33 μm. More specifically, the width of the communicating portion CA may be 19 μm to about 33 μm. Even more specifically, the width of the communicating portion CA may be 20 μm to about 27 μm. If the width of the communicating portion CA exceeds 33 μm, it may be difficult to achieve a resolution of 500 PPI or higher. Furthermore, if the width of the communicating portion CA is less than 15 μm, deposition defects may occur.

[0154] The small facet holes V1 are disposed facing the deposition substrate 300. The small facet holes V1 are disposed close to the substrate 300. Therefore, the small facet holes V1 have a shape corresponding to the deposition material, i.e., the deposition pattern DP.

[0155] The large hole V2 is disposed toward the organic deposition container 400. As a result, the large hole V2 can accommodate the organic material supplied from the organic deposition container 400 over a wide area, and a fine pattern can be quickly formed on the deposition substrate 300 through the small hole V1, which has a smaller width than the large hole V2.

[0156] As a result, the organic material received through the large hole V2 is deposited on the deposition substrate 300 through the small hole V1. As a result, one of red, green, and blue pixel patterns is formed on the deposition substrate 300. Then, the above process is repeated to form all of the red, green, and blue pixel patterns on the deposition substrate 300.

[0157] FIG. 19 is a plan view of an evaporation mask 100 according to an embodiment.

[0158] Referring to FIG. 19, the deposition mask 100 according to the embodiment may include a deposition area DA and a non-deposition area NDA.

[0159] The deposition area DA is an area for forming a deposition pattern. The deposition area DA can include an effective area AA and a non-effective area UA. The effective area AA is defined as an area where through-holes TH through which the organic material passes are formed. The non-effective area UA is defined as an area where through-holes TH through which the organic material passes are not formed. The non-effective area UA is defined as an area where the through-holes TH are formed, but the through-holes TH in the non-effective area UA do not allow the organic material to pass through.

[0160] Although the effective area AA is shown in the drawings as a square, the embodiment is not limited thereto, and the effective area AA may be rectangular, circular, or elliptical.

[0161] The effective area AA may include a plurality of effective areas, which may be spaced apart from each other in the longitudinal direction of the deposition mask.

[0162] The deposition area DA may be defined as an area extending from the start point of the first effective area to the end point of the last effective area in the longitudinal direction of the deposition mask 100 .

[0163] The deposition area DA may be defined as an area extending from the start point of the first non-effective area to the end point of the last non-effective area in the longitudinal direction of the deposition mask 100.

[0164] The non-effective area UA may be defined as an area of ​​the deposition area DA other than the effective area AA. The non-effective area UA may be divided into a first non-effective area UA1 and a second non-effective area UA2 depending on the position of the non-effective area.

[0165] The first non-effective areas UA1 may be defined as areas between the effective areas AA. Thus, a plurality of first non-effective areas UA1 may be spaced apart in the longitudinal direction of the deposition mask 100. In addition, the second non-effective areas UA2 may be defined as areas between the effective areas AA and both ends of the deposition mask 100 in the width direction.

[0166] The non-deposition area NDA is an area that is not involved in deposition. The non-deposition area NDA may include a frame fixing area for fixing the deposition mask 100 to the mask frame 200. The non-deposition area NDA may include at least one of a half-etched portion and an open portion OA. The half-etched portion may be formed by partially etching the metal plate 10. The open portion OA may be formed by completely etching the metal plate 10.

[0167] The half-etched portion can disperse residual stress generated when the deposition mask 100 is stretched, thereby reducing waviness of the deposition mask.

[0168] The open portion OA is an area where a jig such as a clamp is fixed when the deposition mask 100 is pulled.

[0169] The effective area AA may include the through-holes TH, which include the small-surface holes V1, the large-surface holes V2, and the through-holes TH that include the communication portions CA that connect the small-surface holes V1 and the large-surface holes V2.

[0170] The deposition mask is manufactured using the above-described metal plate 10, and therefore can have a nickel and iron content, surface roughness, and thickness uniformity within a set range.

[0171] For example, the test piece S can be measured in any region of the deposition mask. For example, the test piece S can be sampled from at least one of the non-deposition area NDA, the first non-effective area UA1, and the second non-effective area UA2. When the composition, surface roughness, and thickness of the test piece are measured, the deposition mask can have nickel and iron contents, surface roughness, and thickness uniformity within set ranges, similar to the metal plate described above.

[0172] If the nickel content and iron content of the deposition mask are outside the above ranges, the difference in etching uniformity during the formation of through holes may increase, which may lead to an increase in the number of defective through holes in the deposition mask. That is, as shown in FIG. 20, the inclusions may cause defective through holes, which are larger or smaller than other through holes, or defective through holes, which are connected to each other.

[0173] This can result in a decrease in deposition quality when a deposition pattern is formed on a deposition substrate through a deposition mask.

[0174] The features, structures, effects, etc. described in the above-described embodiments are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by a person skilled in the art to which the embodiment belongs. Therefore, content related to such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0175] Furthermore, while the above description has focused on the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art will recognize that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the present invention. For example, each component specifically illustrated in the embodiments can be modified and implemented. Differences related to such modifications and applications should be construed as being included within the scope of the present invention as defined by the appended claims.

Claims

1. A metal plate including a first region and a second region, the metal plate includes Invar containing iron and nickel, The thickness of the metal plate is 20 μm to 50 μm, the thickness of the second region is smaller than the thickness of the first region; the first region and the second region contain 40 wt % or less of nickel in a region from the surface of the metal plate to a depth of 2.5 μm, A metal plate, wherein the nickel content in a region of the first region from the first surface to a depth of 2.5 μm is smaller than the nickel content in a region of the second region from the second surface to a depth of 2.5 μm.

2. The difference between the nickel content in the region from the first surface of the first region to a depth of 2.5 μm and the nickel content in the region from the second surface of the second region to a depth of 2.5 μm is 1 wt% to 6 wt%. The metal plate according to claim 1.

3. The metal plate according to claim 1, wherein the thickness difference between the first region and the second region is greater than 0 μm and less than 0.5 μm.

4. The metal plate according to claim 1 , wherein the roughness of the second surface is less than the roughness of the first surface.

5. A metal plate including Invar containing iron and nickel, The thickness of the metal plate is 20 μm to 30 μm, the metal plate contains 40 wt % or less of nickel in a region from the surface of the metal plate to a depth of 2.5 μm, The metal plate has a nickel weight deviation of 1 wt % to 6 wt % in a region from the surface of the metal plate to a depth of 2.5 μm.

6. Selecting any two sample areas from the surface of the metal plate; 6. The metal plate of claim 5, wherein the deviation of the nickel weight percentage measured in the region from the surface to a depth of 2.5 μm in each sample area is between 1% and 6% by weight.

7. selecting n sample areas from the surface of the metal plate; The average nickel weight percent is defined as the sum of the nickel weight percents measured in each sample area divided by n, The metal plate according to claim 5, wherein the average nickel weight percentage in a region from the surface of the metal plate to a depth of 2.5 μm is 36 wt % to 40 wt %.

8. the metal plate includes a first surface and a second surface opposite the first surface; the minimum arithmetic mean roughness Ra of the first surface is 30 nm to 59 nm; The metal plate according to claim 5, wherein the first surface has a minimum ten-point average roughness Rz of 0.5 nm to 0.79 nm.

9. The metal plate has a thickness deviation defined as a ratio between a maximum thickness value and a minimum thickness value; The metal plate according to claim 5 , wherein the thickness deviation of the metal plate is 3% or less.

10. The metal plate according to any one of claims 1 to 9, the metal plate includes a vapor-deposited region and a non-vapor-deposited region; the vapor deposition area includes an effective area in which through-holes are to be formed and a non-effective area other than the effective area, The through-hole is formed by a small-surface hole, a large-surface hole, and a communicating portion that communicates the small-surface hole and the large-surface hole.

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