Deposition mask for OLED pixel deposition

Abstract

A deposition mask according to an embodiment includes a metal plate having a first surface and a second surface opposite to the first surface, in which the metal plate includes a deposition region and a non-deposition region, in which the deposition region includes an active region in which a plurality of through holes are formed and an inactive region in which the plurality of through holes are formed, and an inactive region in which the plurality of through holes are formed. And the plurality of through holes are formed by a small-area hole formed on the first surface, a large-area hole formed on the second surface, and a connecting portion connecting the small-area hole and the large-area hole, the small-area hole having a step height, the step height is defined as a height of a region in which the width of the small area hole widens when extending from the connecting portion toward the first surface, and wherein the step height of the small area hole is 0 [mu] m.

Description

Technical Field

[0001] This embodiment relates to a deposition mask for OLED pixel deposition. Background Art

[0002] Display devices are applied to various devices. For example, display devices are applied to small devices such as smartphones or tablet PCs. Alternatively, display devices are applied to large devices such as TVs, monitors, and public displays (PDs). Recently, the demand for ultra-high definition (UHD) with a resolution of 500 PPI (pixels per inch) or higher is increasing. Therefore, display devices with high resolution are being applied to small devices and large devices.

[0003] According to the driving method, display devices are classified into LCDs (liquid crystal displays) and OLEDs (organic light emitting diodes).

[0004] An LCD is a display device driven by liquid crystals. In addition, an OLED is a display device driven by organic materials.

[0005] An OLED can achieve infinite contrast, has a response speed 1000 times faster than that of an LCD, and has an excellent viewing angle. Therefore, OLEDs are attracting attention as display devices that can replace LCDs.

[0006] An OLED includes a light-emitting layer. The light-emitting layer includes an organic material. The organic material is deposited on a substrate through a deposition mask. The deposition mask may include an aperture mask (OM) or a fine metal mask (FMM). A deposition pattern corresponding to the pattern formed in the deposition mask is formed on the substrate. Therefore, the deposition pattern can be used as a pixel.

[0007] An aperture mask is a thin plate that forms a deposition pattern only at specific positions when manufacturing an OLED. The aperture mask is used to perform the deposition process of the light-emitting layer on the backplane after the backplane is completed during the display manufacturing process. In other words, the aperture mask is a mask that does not have a coverage area within the range of display operation for depositing the entire surface of the display. Therefore, when depositing a light-emitting layer using a light-emitting material of one color, an aperture mask is used.

[0008] On the other hand, a fine metal mask is used to change the color of sub-pixels of the light-emitting layer. Therefore, the fine metal mask includes ultra-fine holes. The process using the fine metal mask must perform several deposition stages. Therefore, this process requires precise alignment. Therefore, the process using the fine metal mask is more difficult than the process using the aperture mask.

[0009] When depositing the light-emitting layer of an OLED through an aperture mask, only a light-emitting layer of one color is formed. Therefore, a separate color filter (C / F) is required to achieve various colors. On the other hand, when using a fine metal mask, RGB light-emitting layers can be formed. Therefore, a separate color filter is not required. In other words, the technology using a fine metal mask is more difficult. However, different from the method using an aperture mask, since the method using a fine metal mask does not require a light filter to block light, the method using a fine metal mask has higher light efficiency.

[0010] The fine metal mask is generally made of an Invar alloy metal plate containing iron (Fe) and nickel (Ni). Through holes are formed on one surface and the other surface of the metal plate and penetrate through one surface and the other surface. The through holes are formed at positions corresponding to the pixel patterns. Therefore, red, green, and blue organic materials can pass through the through holes of the metal plate and be deposited on the substrate. Thus, pixel patterns can be formed on the substrate.

[0011] Meanwhile, the fine metal mask includes small-area holes formed on one surface of the metal plate and large-area holes formed on the other surface of the metal plate. The small-area holes and the large-area holes are connected by connecting portions to form through holes.

[0012] The organic material is sprayed towards the fine metal mask. The organic material enters through the large-area holes and exits through the small-area holes, and is deposited on the deposition substrate.

[0013] Specifically, a plurality of strip-shaped fine metal masks are arranged on the deposition substrate. The organic material moves from the large-area holes to the small-area holes.

[0014] At this time, the deposition pattern formed on the deposition substrate can form a shadow area according to the shape of the small-area holes. The shadow area is a pattern formed outside the deposition pattern. Due to the shadow area, adjacent patterns may overlap each other.

[0015] Therefore, the deposition quality and deposition reliability of the deposition mask may be reduced.

[0016] Therefore, a deposition mask with a new structure that can solve the above problems is needed. Summary of the Invention

[0017] Technical Problem

[0018] The present invention provides a deposition mask with improved deposition reliability and deposition quality.

[0019] Technical Solution

[0020] The deposition mask according to the embodiment includes a metal plate having a first surface and a second surface opposite to the first surface, wherein the metal plate includes a deposition region and a non-deposition region, wherein the deposition region includes an effective region and an ineffective region, wherein a plurality of through holes are formed in the effective region, and the plurality of through holes are formed by small-area holes formed on the first surface, large-area holes formed on the second surface, and connecting portions connecting the small-area holes and the large-area holes, wherein the small-area holes have a step height defined as the height of a region where the width of the small-area holes widens when extending from the connecting portion toward the first surface, and wherein the step height of the small-area holes is 0 μm.

[0021] Advantageous Effects

[0022] The deposition mask according to the embodiment includes small-area holes. The small-area holes have a step height of a set size.

[0023] The step height of the small-area holes can be 0. Accordingly, the size of the shadow region is reduced. Accordingly, overlapping of adjacent deposition patterns can be prevented.

[0024] Alternatively, the step height of the small-area holes can be greater than 0 and less than or equal to 5 μm. Accordingly, the size of the shadow region is reduced. In addition, the amount of the organic material disposed on the first surface of the deposition mask is minimized. Accordingly, separation of the deposition mask and the deposition substrate becomes easy.

[0025] In addition, the deposition mask according to the embodiment includes protrusions. The protrusions are disposed on the first surface where the small-area holes are formed.

[0026] Accordingly, when the organic material is present between the first surface and the deposition substrate, the deposition mask and the deposition substrate are easily separated by the protrusions.

[0027] Accordingly, when the deposition mask is separated, damage to the deposition mask can be prevented.

[0028] In addition, the surface roughness of the first surface is less than the surface roughness of the second surface.

[0029] Accordingly, the amount of the organic material deposited on the first surface is reduced. Accordingly, the deposition mask and the deposition substrate are easily separated by the protrusions.

[0030] Accordingly, when separating the deposition mask, damage to the deposition mask can be prevented.

[0031] In addition, a gap between the deposition mask and the deposition substrate can be prevented. Accordingly, the size and shape of the deposition pattern become uniform.

[0032] Accordingly, the deposition quality of the deposition mask is improved. Description of the Drawings

[0033] Figure 1 is a drawing showing a combination of a deposition mask and a frame according to an embodiment.

[0034] Figure 2 is a cross-sectional view of an organic deposition apparatus including a deposition mask according to an embodiment.

[0035] Figure 3 is a drawing showing a deposition pattern formed on a deposition substrate through a through hole of a deposition mask according to an embodiment.

[0036] Figure 4 is a drawing for explaining a difference in a deposition pattern according to a step height of a deposition mask according to an embodiment.

[0037] Figure 5 is a top view of a deposition mask according to an embodiment.

[0038] Figure 6 and Figure 7 is along Figure 5 a cross-sectional view taken along region C-C' of.

[0039] Figure 8 is a drawing for explaining a change in a step height corresponding to electropolishing of a small-area hole of a deposition mask according to an embodiment.

[0040] Figure 9 is along Figure 5 a cross-sectional view taken along region D-D' of the.

[0041] Figure 10 is a drawing for explaining an effect of a protrusion of a deposition mask according to an embodiment.

[0042] Figure 11 is a drawing for explaining a surface roughness of a deposition mask according to an embodiment.

[0043] Figure 12 is a drawing for explaining a relationship between a surface roughness and a current density of a deposition mask according to an embodiment.

[0044] Figure 13 is a photograph of a first surface and a second surface of a deposition mask according to an embodiment. Detailed Description

[0045] In the following, embodiments will be described in detail with reference to the accompanying drawings. However, the spirit and scope of the present invention are not limited to a part of the described embodiments, and can be implemented in various other forms, and within the spirit and scope of the present invention, one or more of the elements of the embodiments can be selectively combined and replaced. In addition, unless otherwise clearly defined and described, the terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as having the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains, and terms such as those defined in a commonly used dictionary can be interpreted as having a meaning consistent with their meaning in the context of the relevant field.

[0046] In addition, the terms used in the embodiments of the present invention are used to describe the embodiments and are not intended to limit the present invention. In this specification, unless specifically stated in a phrase, the singular form may also include the plural form, and may include at least one of all combinations that can be combined among A, B, and C when described as "at least one (or more) of A, B, and C".

[0047] In addition, when describing the elements of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the elements from other elements and are not limited to the nature, order, or order of the elements.

[0048] In addition, when an element is described as "connected", "coupled", or "connected to" another element, it may include not only the case where the element is directly "connected", "coupled", or "connected to" the other element, but also the case where the element is "connected", "coupled", or "connected to" the other element through other elements between the element and the other element.

[0049] In addition, when described as being "on (above)" or "under (below)" each element, "on (above)" or "under (below)" may include not only the case where two elements are directly connected to each other, but also the case where one or more other elements are formed or arranged between the two elements.

[0050] In addition, when expressed as "on (above)" or "under (below)", based on one element, it may include not only the upward direction but also the downward direction.

[0051] The deposition mask described below is a fine metal mask (FMM), which can form an RGB pixel pattern on a deposition substrate by depositing organic materials such as red, green, and blue on the deposition substrate, and the following description does not apply to an aperture mask (OM).

[0052] In the following description, the first direction is the length direction of the deposition mask. In addition, the second direction is the width direction of the deposition mask.

[0053] In the following description, the height of the small-area hole is the height from the connection part to the first surface. In addition, the step height of the small-area hole is the height of the region where the width of the small-area hole widens in the direction extending from the connection part to the first surface.

[0054] Hereinafter, a deposition mask according to an embodiment will be described with reference to the accompanying drawings.

[0055] Figures 1 to 3 is a drawing for explaining a process of depositing an organic material on a deposition substrate 300 using a deposition mask 100 according to an embodiment.

[0056] Referring to Figure 1 and Figure 2 , the organic material deposition apparatus includes a deposition mask 100, a mask frame 200, a deposition substrate 300, an organic material deposition container 400, and a vacuum chamber 500.

[0057] The deposition mask 100 includes metal. For example, the deposition mask includes iron (Fe) and nickel (Ni). Specifically, the deposition mask includes an Invar alloy containing iron (Fe) and nickel (Ni).

[0058] The deposition mask 100 includes a plurality of through holes TH. The through holes are provided in the effective portion. The through holes are provided to correspond to pixel patterns to be formed on the deposition substrate.

[0059] The mask frame 200 includes an opening 205. A plurality of through holes are provided in a region corresponding to the opening 205. Accordingly, 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 is tensioned with a constant tension. In addition, the deposition mask 100 is welded and fixed to the mask frame 200.

[0060] For example, the non-effective region of the deposition mask 100 is welded. Thereby, the deposition mask 100 is fixed to the mask frame 200. Then, the outwardly protruding portions of the mask frame 200 are cut and removed.

[0061] The mask frame 200 includes a metal having high rigidity. Thereby, deformation of the mask frame is reduced during the welding process.

[0062] The deposition substrate 300 is a substrate used in manufacturing a display device. For example, an OLED pixel pattern is formed on the deposition substrate 300. In order to form pixels that are the three primary colors of light, red, green, and blue organic patterns are formed on the deposition substrate 300. That is, an RGB pattern is formed on the deposition substrate 300.

[0063] The organic material deposition container 400 is a crucible. An organic material is disposed 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 in the width direction of the deposition mask 100 within the vacuum chamber 500.

[0064] A heat source and / or an electric current is supplied to the organic material deposition container 400. Accordingly, the organic material is deposited on the deposition substrate 300.

[0065] Referring to Figure 3 , the deposition mask 100 includes a metal plate 10. The metal plate includes a first surface 1S and a second surface 2S. The first surface 1S and the second surface 2S are opposite surfaces.

[0066] The first surface 1S includes small area holes V1. The second surface 2S includes large area holes V2. For example, a plurality of small area holes V1 and a plurality of large area holes V2 are respectively formed on the first surface 1S and the second surface 2S.

[0067] In addition, the deposition mask 100 includes a through hole TH. The through hole TH is formed by a connecting portion CA that connects the boundaries of the small area holes V1 and the large area holes V2.

[0068] The width of the large area holes V2 is greater than the width of the small area holes V1. The width of the small area holes V1 is measured on the first surface 1S of the deposition mask 100. The width of the large area holes V2 is measured on the second surface 2S of the deposition mask 100.

[0069] In addition, the width of the connecting portion CA has a set dimension. Specifically, the width of the connecting portion CA can be 15 μm to 33 μm. More specifically, the width of the connecting portion CA can be 19 μm to 33 μm. More specifically, the width of the connecting portion CA can be 20 μm to 27 μm. If the width of the connecting portion CA exceeds 33 μm, it is difficult to achieve a resolution of more than 500 PPI. In addition, if the width of the connecting portion CA is less than 15 μm, defects may occur during the deposition process.

[0070] The small area holes V1 face the deposition substrate 300. The small area holes V1 are arranged to be close to the deposition substrate 300. Accordingly, the small area holes V1 have a shape corresponding to the deposition pattern DP.

[0071] The large area holes V2 face the organic material deposition container 400. Accordingly, the organic material supplied from the organic material deposition container 400 can be received through the large area holes V2 in a wide width. In addition, through the small area holes V1, a fine pattern can be quickly formed on the deposition substrate 300.

[0072] Therefore, the organic material accommodated in the large-area hole V1 is deposited on the deposition substrate 300 through the small-area hole V1. Accordingly, one of the red, green, or blue pixel patterns is formed on the deposition substrate 300. Subsequently, the above process is repeated. Accordingly, all the red, green, or blue pixel patterns are formed on the deposition substrate 300.

[0073] Referring to Figure 3 , the small-area hole V1 has a step height SH. The step height SH is the height of the region where the width of the small-area hole V1 widens in the direction extending from the connection portion toward the first surface 1S. In addition, the step height SH is the region where the angle (θ1) formed by the connection portion CA and the inner surface ES of the small-area hole V1 is an obtuse angle or a right angle.

[0074] The boundary region between the small-area hole V1 and the first surface 1S may have a curvature. In addition, the boundary region between the large-area hole V2 and the second surface 2S may also have a curvature. The region where the width of the small-area hole widens due to the curvature is excluded from the step height SH. That is, the Figure 7 corner region M is excluded from the step height SH.

[0075] The corner region M is a tolerance that occurs when manufacturing the deposition mask. For example, when forming the large-area hole, the corner where the small-area hole meets the first surface may have a small curvature formed by the etching solution. Alternatively, the corner where the inner surface of the through hole meets the first surface may have a curvature formed during the electropolishing process. Alternatively, the corner where the inner surface of the through hole meets the second surface may have a curvature formed during the electropolishing process. The corner region may be the region where the curvature is formed.

[0076] The height H of the small-area hole V1 is the height from the connection portion CA to the first surface 1S.

[0077] Therefore, when the width of the small-area hole V1 widens from the connection portion in the direction of the first surface 1S, the step height SH and the height H of the small-area hole may be the same or similar.

[0078] Alternatively, when the angle (θ1) formed between the connection portion CA and the inner surface ES of the small-area hole V1 is an obtuse angle, the step height SH and the height H of the small-area hole may be the same or similar.

[0079] On the other hand, when the width of the small-area hole V1 narrows from the connection portion in the direction of the first surface 1S, the step height SH and the height H of the small-area hole may be different.

[0080] Alternatively, when the angle (θ1) formed between the connection portion CA and the inner surface ES of the small-area hole V1 is an acute angle or a right angle, the step height SH and the height H of the small-area hole may be different.

[0081] Figure 4 It is a diagram for explaining the difference in the deposition pattern according to the step height SH of the small-area hole V1.

[0082] Figure 4 In (a) of, it is a diagram showing the deposition pattern DP when the step height SH of the small-area hole V1 is relatively small. Figure 4 In (b) of, it is a diagram showing the deposition pattern DP when the step height SH of the small-area hole V1 is relatively large.

[0083] The deposition pattern DP may include a first region 1A and a second region 2A. The width of the first region 1A varies according to the width of the connection part CA. The width of the second region 2A varies according to the step height SH.

[0084] The thickness of the first region 1A may be uniform. In addition, the thickness of the second region 2A may be non-uniform.

[0085] That is, the first region 1A and the second region 2A may be deposition patterns provided on the deposition substrate 300. In addition, the second region 2A is a region where the organic material expands in the deposition pattern DP. That is, the second region 2A is a shaded region. The width of the second region 2A may increase as the step height SH increases. If the width of the second region 2A increases beyond the set range, adjacent deposition patterns may overlap each other. Therefore, there is a problem of reduced deposition quality of the deposition mask.

[0086] Hereinafter, a deposition mask capable of solving the above problems will be described.

[0087] Referring to Figures 5 to 13 , the deposition mask 100 includes a deposition region DA and a non-deposition region NDA.

[0088] The deposition region DA is a region for forming a deposition pattern. The deposition region DA includes an effective region AA and an ineffective region UA. The effective region AA is a region where a through hole TH through which an organic material passes is formed. In addition, the ineffective region UA is a region where the through hole TH is not formed.

[0089] In the figure, the effective region AA is shown as a square. However, the embodiment is not limited thereto. The effective region AA may have a rectangular shape or a circular shape.

[0090] The effective region AA includes a plurality of effective regions. The plurality of effective regions are spaced apart in the first direction.

[0091] The deposition region DA is a region from the point where the first effective region starts to the point where the last effective region ends in the first direction.

[0092] The ineffective region UA is the deposition region other than the effective region AA.

[0093] The non-deposition area NDA is the area that does not participate in deposition. The non-deposition area NDA includes the frame fixing areas FA1 and FA2. The frame fixing areas are the areas for fixing the deposition mask 100 to the mask frame 200. In addition, the non-deposition area NDA may include at least one of the semi-etched part HF and the opening part OA. The semi-etched part HF is formed by partially etching the metal plate 10. The opening part OA is formed by completely etching the metal plate 10.

[0094] The residual stress generated when the deposition mask 100 is tensioned is dispersed by the semi-etched part HF. Therefore, the waviness of the deposition mask is reduced.

[0095] In addition, a fixture such as a clamp used when tensioning the deposition mask 100 is fixed to the opening part OP.

[0096] A plurality of through holes TH are formed inside the effective area AA. A plurality of island parts IS are provided between the plurality of through holes TH. The island part IS is a surface where the first surface 1S or the second surface 2S is not etched. The island part IS connects adjacent ribs RB. The rib RB is the area where the inner surfaces of adjacent through holes meet. The rib RB is the area where the metal plate 10 is partially etched.

[0097] Refer to Figure 6 and Figure 7 , the metal plate 10 includes a first surface 1S and a second surface 2S opposite to the first surface 1S.

[0098] A plurality of small area holes V1 are formed on the first surface 1S. A large area hole V2 is formed on the second surface 2S.

[0099] The small area holes V1 and the large area hole V2 are connected by a connecting part CA. Thus, through holes TH are formed.

[0100] The step height SH of the small area holes V1 can have a set range.

[0101] Refer to Figure 6 , the step height SH of the small area holes V1 can be 0 μm. Specifically, the width of the small area holes V1 can be made narrower from the connecting part CA toward the first surface 1S. In addition, the step height SH can be 0 μm. That is, the height H of the small area holes V1 can be within a set range, and the step height SH can be 0 μm.

[0102] That is, the angle (θ1) formed by the inner surface ES of the small area holes V1 and the connecting part CA can be an acute angle or a right angle. In addition, the angle (θ2) formed by the inner surface ES of the small area holes V1 and the first surface 1S can be an obtuse angle or a right angle. In addition, the step height SH can be 0.

[0103] Therefore, the shadow area of the deposition pattern is reduced. Specifically, the width of the small-area hole V1 narrows from the connection part CA toward the first surface 1S. Accordingly, when the organic material is deposited on the deposition substrate 300, the area where the organic material spreads outward is reduced.

[0104] Therefore, overlapping of the deposition pattern according to the shadow area can be prevented. Accordingly, the deposition reliability of the deposition mask is improved.

[0105] Referring to Figure 7 , the small-area hole V1 can have a step height SH within a set range. Specifically, the step height SH of the small-area hole V1 can be 5 μm or less. More specifically, the step height SH of the small-area hole V1 can be greater than 0 μm and less than or equal to 5 μm, and can be 0.01 μm to 3 μm, 0.1 μm to 2.5 μm, or 1 μm to 2.2 μm.

[0106] The step height SH of the small-area hole V1 can be controlled by a process of etching or polishing the small-area hole V1. For example, the step height SH can be controlled by selectively performing wet etching or dry etching on the small-area hole V1. Alternatively, the step height SH can be controlled by electro-polishing, chemical polishing, mechanical polishing, or chemical mechanical polishing (CMP) of the small-area hole V1.

[0107] For example, the step height SH can be controlled by electro-polishing. The step height SH can be changed according to the magnitude of the current applied and the application time during the electro-polishing process. Specifically, referring to Figure 8 , depending on the magnitude of the current and the application time, the step height SH can be greater than 0 μm and less than or equal to 5 μm. That is, the step height SH can decrease as the time of the current and / or the magnitude of the current increases.

[0108] Specifically, the width of the small-area hole V1 widens from the connection part CA toward the first surface 1S, and the step height SH can have the above range.

[0109] That is, the angle formed by the inner surface ES of the small-area hole V1 and the connection part CA can be an obtuse angle. In addition, the angle (θ2) formed by the inner surface ES of the small-area hole V1 and the first surface 1S can be an acute angle. In addition, the step height SH can also have the above range.

[0110] In addition, the angle (θ2) formed by the inner surface ES of the small-area hole V1 and the first surface 1S can be 35° to 55°.

[0111] When the step height SH exceeds 5 μm, the shadow area may increase. Therefore, adjacent deposition patterns may overlap. Accordingly, the deposition reliability of the deposition mask is reduced.

[0112] Therefore, the step height SH of the small-area hole V1 is controlled within the above range. Accordingly, when the organic material is deposited on the deposition substrate 300, the area where the organic material spreads in the outward direction is reduced.

[0113] Therefore, overlapping of the deposition pattern according to the shadow area can be prevented. Accordingly, the deposition mask has improved deposition reliability.

[0114] In addition, the small-area hole has a set step height. Accordingly, the deposition of the organic material on the first surface adjacent to the small-area hole is minimized. Accordingly, separation of the deposition mask and the deposition substrate becomes easy.

[0115] Referring to Figure 9 and Figure 10 , the deposition mask 100 may include at least one protrusion 15.

[0116] The protrusion 15 is disposed in the non-deposition area NDA. The protrusion 15 is disposed on the first surface 1S.

[0117] The protrusion 15 and the metal plate 10 may include the same material. For example, the protrusion 15 may be integrally formed with the metal plate 10. The embodiment is not limited thereto. The protrusion 15 may include a material different from that of the metal plate 10. In addition, the protrusion 15 may be separated from the metal plate 10.

[0118] For example, the protrusion 15 and the metal plate 10 may include the same material. In addition, the protrusion 15 may be formed together when forming the through hole. Specifically, after forming the small-area hole and the large-area hole, the first surface may be additionally etched to control the step height. For example, the first surface may be additionally etched by an electropolishing process.

[0119] At this time, a mask is placed in the area where the protrusion is formed. Accordingly, the area where the mask is placed is not etched, thereby forming a protrusion on the first surface.

[0120] The deposition mask 100 and the deposition substrate 300 are easily separated by the protrusion.

[0121] Referring to Figure 10 , the small-area hole V1 may have a step height SH. The organic material 450 may flow into the area adjacent to the small-area hole V1. Accordingly, the organic material 450 may be deposited on the first surface 1S. The deposition mask 100 and the deposition substrate 300 may be bonded by the organic material deposited on the first surface. Accordingly, separation of the deposition mask 100 from the deposition substrate 300 becomes difficult. In addition, when the deposition mask 100 is separated from the deposition substrate 300, the deposition mask 100 may be damaged.

[0122] Therefore, at least one protrusion is provided on the first surface. Thus, the above problems can be solved. That is, when the organic material is deposited on the first surface 1S, the deposition mask 100 and the deposition substrate 300 are easily separated by the protrusion.

[0123] In Figure 9 and Figure 10 the protrusion 15 is shown as being provided in the non-deposition area. However, the embodiment is not limited thereto. The protrusion 15 may be provided in the deposition area. Alternatively, the protrusion 15 may also be arranged in both the non-deposition area and the deposition area.

[0124] Referring to Figure 11 the first surface 1S and the second surface 2S may include patterns. Specifically, the first surface 1S includes a plurality of first patterns P1. The second surface 2S includes a plurality of second patterns P2.

[0125] Therefore, the first surface 1S and the second surface 2S have a surface roughness within a set range. The first surface 1S has a first surface roughness. In addition, the second surface 2S has a second surface roughness.

[0126] The first surface roughness and the second surface roughness may be different. Specifically, the first surface roughness may be less than the second surface roughness.

[0127] The first surface roughness may have an arithmetic mean roughness (Ra) of 30 nm to 160 nm. Specifically, the first surface roughness may have an arithmetic mean roughness (Ra) of 35 nm to 80 nm or 35 nm to 75 nm.

[0128] In addition, the first surface roughness may have a ten-point mean roughness (Rz) of 0.5 μm to 1.7 μm. Specifically, the first surface roughness may have a ten-point mean roughness (Rz) of 0.5 μm to 1.5 μm or 0.5 μm to 1.1 μm.

[0129] The first surface roughness may vary according to the current density during the electropolishing process. Specifically, when the magnitude of the current applied and / or the current application time increases during the electropolishing process, the magnitude of the first surface roughness decreases.

[0130] Specifically, referring to Figure 12 in a second part where the current density is twice that of the first part, the arithmetic mean roughness (Ra) and the ten-point mean roughness (Rz) of the first surface 1S decrease.

[0131] The first surface roughness has the above range. In addition, the first surface roughness is less than the second surface roughness. That is, referring to Figure 13 the first surface roughness of the first surface ( Figure 13is less than the second surface roughness of the second surface ( Figure 13 of (b)).

[0132] As described above, after forming the small-area holes and the large-area holes, the first surface is additionally etched or polished. Therefore, the surface roughness of the first surface 1S becomes less than the surface roughness of the second surface 2S.

[0133] By reducing the surface roughness of the first surface, the deposition mask 100 and the deposition substrate 300 are easily separated.

[0134] The small-area holes V1 may have a step height SH. The organic material 450 may flow into the area adjacent to the small-area holes V1. Therefore, the organic material 450 may be deposited on the first surface 1S. The deposition mask 100 and the deposition substrate 300 may be bonded by the organic material deposited on the first surface. Therefore, the separation of the deposition mask 100 from the deposition substrate 300 becomes difficult. In addition, when the deposition mask 100 is separated from the deposition substrate 300, the deposition mask 100 may be damaged.

[0135] Therefore, the surface roughness of the first surface is reduced. Therefore, the amount of the organic material deposited on the first surface 1S can be reduced. Therefore, the separation of the deposition mask 100 from the deposition substrate 300 becomes easy.

[0136] In addition, the gap between the deposition mask 100 and the deposition substrate 300 is minimized.

[0137] Therefore, the distance between the deposition mask 100 and the deposition substrate 300 becomes uniform. Therefore, the shape or size of the deposition pattern becomes uniform, thereby improving the deposition quality.

[0138] The deposition mask according to the embodiment includes small-area holes. The small-area holes have a step height of a set size.

[0139] The step height of the small-area holes may be 0. Therefore, the size of the shadow area is reduced. Therefore, it is possible to prevent adjacent deposition patterns from overlapping.

[0140] Alternatively, the step height of the small-area holes may be greater than 0 and less than or equal to 5 μm. Therefore, the size of the shadow area is reduced. In addition, the amount of the organic material disposed on the first surface of the deposition mask is minimized. Therefore, the separation of the deposition mask and the deposition substrate becomes easy.

[0141] In addition, the deposition mask according to the embodiment includes protrusions. The protrusions are disposed on the first surface where the small-area holes are formed.

[0142] Therefore, when the organic material exists between the first surface and the deposition substrate, the deposition mask and the deposition substrate are easily separated by the protrusions.

[0143] Therefore, when the deposition mask is separated, damage to the deposition mask can be prevented.

[0144] In addition, the surface roughness of the first surface is less than that of the second surface.

[0145] Therefore, the amount of the organic material deposited on the first surface is reduced. As a result, the deposition mask and the deposition substrate are easily separated by the protrusions.

[0146] Therefore, when the deposition mask is separated, damage to the deposition mask can be prevented.

[0147] In addition, a gap between the deposition mask and the deposition substrate can be prevented. As a result, the size and shape of the deposition pattern become uniform.

[0148] The features, structures, and effects described in the above embodiments are included in at least one embodiment, but are not limited to one embodiment. In addition, the features, structures, effects, etc. shown in each embodiment can even be combined or modified by those of ordinary skill in the art to which the embodiment pertains with respect to other embodiments. Therefore, the content related to such combinations and such modifications should be construed as being included within the scope of the embodiments.

[0149] The above description focuses on the embodiments, but is merely illustrative and does not limit the embodiments. Those skilled in the art to which the present embodiments pertain can understand that various modifications and applications not shown above are possible without departing from the basic features of the present embodiments. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, the differences related to such variations and applications should be construed as being included within the scope of the embodiments defined in the appended claims.

Claims

1. A deposition mask, the deposition mask comprising: A metal plate having a first surface and a second surface opposite to the first surface, wherein the metal plate includes a deposition region and a non-deposition region, wherein the deposition region includes an effective region and an ineffective region, wherein a plurality of through holes are formed in the effective region, and the plurality of through holes are formed by small area holes formed on the first surface, large area holes formed on the second surface, and connecting portions connecting the small area holes and the large area holes, wherein the small area holes have a step height, the step height being defined as the height of a region where the width of the small area holes widens when extending from the connecting portion towards the first surface, and wherein the step height of the small area holes is 0 μm.

2. The deposition mask according to claim 1, wherein The angle formed by the connecting portion and the inner surface of the small area hole is an acute angle or a right angle.

3. A deposition mask, the deposition mask comprising: A metal plate having a first surface and a second surface opposite to the first surface, wherein the metal plate includes a deposition region and a non-deposition region, wherein the deposition region includes an effective region and an ineffective region, wherein a plurality of through holes are formed in the effective region, and the plurality of through holes are formed by small area holes formed on the first surface, large area holes formed on the second surface, and connecting portions connecting the small area holes and the large area holes, wherein the small area holes have a step height, the step height being defined as the height of a region where the width of the small area holes widens when extending from the connecting portion towards the first surface, and wherein the step height of the small area holes is greater than 0 μm and less than or equal to 5 μm, and wherein the surface roughness of the small area holes is less than the surface roughness of the large area holes.

4. The deposition mask according to claim 3, wherein, The arithmetic mean roughness (Ra) of the small area holes is 30 nm to 160 nm.

5. The deposition mask according to claim 1 or 3, further comprising: Protrusions provided on the first surface.

6. The deposition mask according to claim 5, wherein, The protrusions are provided on at least one of the deposition region and the non-deposition region.

7. The deposition mask according to claim 5, wherein, The protrusions are integrally formed with the metal plate.

8. The deposition mask according to claim 1, wherein, The surface roughness of the first surface is different from the surface roughness of the second surface.

9. The deposition mask according to claim 8, wherein The surface roughness of the first surface is less than the surface roughness of the second surface.

10. The deposition mask according to claim 9, wherein, The surface roughness of the first surface has an arithmetic mean roughness (Ra) of 30 nm to 160 nm or a ten-point mean roughness of 0.5 μm to 1.7 μm.

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