Mask for OLED and manufacturing method thereof
By combining substrates with different thermal expansion coefficients and applying stress during evaporation, the problems of FMM sag and shading effects are solved, and the high resolution of OLED and reuse and warp adjustment of FMM are achieved.
Patent Information
- Application Number
- CN202411042720.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-02
- Filing Date
- 2024-07-31
- Publication Date
- 2025-02-14
AI Technical Summary
In the existing OLED manufacturing technology, FMM sags due to its own weight, resulting in a shadow effect, and requires additional equipment and time to be fixed and reused.
By combining the second substrate with different coefficients of thermal expansion with the first substrate, the FMM is bent into a convex shape upwards by using the difference in thermal expansion, reducing sagging, and applying tensile stress or compression stress during the evaporation film to adjust the warping degree.
The FMM is efficiently attached to the substrate, reducing the shadow effect, improving the high resolution and alignment ease of OLEDs, and allowing reuse and warp adjustment of FMMs.
Smart Images
Figure CN119433432A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an OLED mask and a method for manufacturing the same, and more particularly to an OLED mask that can be manufactured using existing semiconductor equipment without requiring additional equipment and a method for manufacturing the same. Background Art
[0002] OLED (Organic Light-Emitting Diode) is an organic light-emitting diode that uses organic compounds to generate light. Such organic compounds can emit light when electricity flows through each pixel. Unlike plasma displays or LCD (Liquid Crystal Display), OLED displays do not require a backlight or LED backlight, and individual pixels emit light directly, so they can provide high contrast and wide viewing angles.
[0003] Such OLED manufacturing includes various steps such as metal substrate manufacturing, transparent electrode pattern manufacturing, organic light-emitting material layer evaporation, electrode pattern manufacturing and protective layer attachment.
[0004] The organic light-emitting material layer is deposited by evaporating the core of OLED, the organic light-emitting material layer, on the pixel of TFT (Thinfilm transistor). Such an organic light-emitting material layer plays the role of emitting light, and various organic compounds are used to present various colors.
[0005] In order to deposit the organic light-emitting material layer, a fine metal mask (FMM) is used. The FMM is composed of a metal plate having fine holes.
[0006] Figure 6 Schematic diagram showing the process of evaporating an organic light-emitting material using FMM according to the conventional technology.
[0007] See also Figure 6 , the organic matter can be heated at the evaporation source located below, the heated organic matter sublimates, and the green, red, blue and other organic light-emitting substances are accurately evaporated and arranged in the OLED sub-pixels through the first hole of the FMM located above.
[0008] exist Figure 6 In the figure, for the sake of convenience, the FMM is shown as being separated from the substrate, but in fact, the evaporation occurs in a state where the FMM is in close contact with the substrate. Thus, the organic light-emitting material is evaporated at an accurate position corresponding to the first hole of the FMM.
[0009] However, when evaporation is performed from the evaporation source below to the top, the FMM may sag due to its own weight. If a gap is formed between the FMM and the substrate, a shadow effect may occur, which prevents the evaporation from being performed normally. Therefore, in order to prevent such a phenomenon, the FMM is bent or warped. For example, Figure 6 In this way, the FMM is warped in a “⌒” shape or convexly curved upward. This allows the FMM to be more closely attached to the substrate.
[0010] In the prior art, when fixing the FMM, an additional stretcher is used to apply a stretching force to the FMM to prevent it from sagging. However, if an additional device is used in this way, it requires a space for setting up the stretching device, and a lot of additional processes and time are required to move the FMM to perform operations on the stretcher.
[0011] Furthermore, FMMs manufactured using Invar in the past are difficult to reuse, and thus a large amount of cost and time are required to manufacture FMMs. Summary of the invention
[0012] In order to solve the above-mentioned problems, an object of the present invention is to provide an OLED mask and a method for manufacturing the same, which enable manufacturing of FMM using equipment and devices used in conventional semiconductor equipment.
[0013] Another object of the present invention is to provide an OLED mask and a method for manufacturing the same, which can reduce the shadow effect by causing the FMM to warp upward and thereby reduce the sagging of the central portion.
[0014] Furthermore, an object of the present invention is to provide an OLED mask that can be repeatedly used and in which the warpage of the FMM can be adjusted to a desired level when repeatedly used, and a method for manufacturing the same.
[0015] The object of the present invention as described above is achieved by a method for manufacturing a mask for OLED, which is characterized in that it includes: a step of providing a first substrate formed of metal with a plurality of first holes formed therein; a step of attaching a second substrate having a thermal expansion coefficient different from that of the first substrate to the underside of the first substrate to manufacture the mask; and a step of heating the mask.
[0016] Wherein, the thermal expansion coefficient of the first substrate may be larger than that of the second substrate.
[0017] In addition, the first substrate may be composed of any one selected from beryllium, iron, nickel, chromium, tungsten, cobalt, molybdenum, tin, zinc-titanium, aluminum, tungsten carbide and platinum, or an alloy of two or more thereof.
[0018] Furthermore, the first substrate may be made of beryllium, or an alloy of beryllium and at least one selected from iron, nickel, chromium, tungsten, cobalt, molybdenum, tin, zinc-titanium, aluminum, tungsten carbide, and platinum.
[0019] On the other hand, in the step of heating the mask, the mask may be bent into a convex shape facing upward.
[0020] Furthermore, the method for manufacturing an OLED mask may further include the step of applying tensile stress or compressive stress to the mask by vapor-depositing a thin film on at least one of the upper surface of the first substrate and the lower surface of the second substrate.
[0021] In addition, in the step of applying tensile stress or compressive stress to the mask by evaporating the thin film, at least one of the type of process gas supplied, the supply amount of the process gas, the supply speed of the process gas, the intensity of the voltage applied to generate plasma, the pressure in the chamber, and the thickness of the evaporated thin film is adjusted to apply tensile stress or compressive stress.
[0022] On the other hand, the purpose of the present invention as described above is achieved by a mask for OLED, which is characterized in that it includes: a first substrate formed of a metal having a plurality of first holes; and a second substrate arranged under the first substrate and having a thermal expansion coefficient different from that of the first substrate.
[0023] The mask may be formed by bending in a convex shape toward the upper side.
[0024] Furthermore, a thin film may be further provided on at least one of the upper surface of the first substrate and the lower surface of the second substrate.
[0025] According to the present invention having the above structure, when manufacturing the mask for OLED, that is, FMM, no additional equipment and devices are required, and the equipment and devices used in existing semiconductor equipment can be used, thereby reducing the cost and space constraints caused by the equipment.
[0026] In addition, according to the present invention, the FMM is warped upward to reduce the shadow effect, thereby achieving high resolution, and further reducing the sagging of the central portion, so that the alignment of the FMM can be further easily performed.
[0027] Furthermore, according to the present invention, the FMM can be reused, and when it is reused, the warpage of the FMM can be adjusted to a desired level. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1is a diagram of a step of attaching a second substrate having a different thermal expansion coefficient under a first substrate according to an embodiment of the present invention,
[0029] Figure 2 is a bottom view of the second substrate,
[0030] Figure 3 is a bottom view of a state where the second substrate is attached to the first substrate,
[0031] Figure 4 is a side view showing a state where warpage occurs in the mask,
[0032] Figure 5 It is enlarged to show Figure 4 A local area graph,
[0033] Figure 6 Schematic diagram showing the process of evaporating an organic light-emitting material using FMM according to the conventional technology.
[0034] (Explanation of Reference Numerals)
[0035] 100: First substrate
[0036] 110: First hole
[0037] 200: Second substrate
[0038] 210: Opening
[0039] 220: Second hole
[0040] 400: Mask for OLED DETAILED DESCRIPTION
[0041] Hereinafter, the method for manufacturing an OLED (Organic Light-Emitting Diode) mask according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the OLED mask used in this specification corresponds to the FMM (Fine Metal Mask) used for evaporating an organic light-emitting material layer in the OLED manufacturing step.
[0042] According to an embodiment of the present invention, a method for manufacturing an OLED mask may include: providing a first substrate 100 formed of metal with a plurality of first holes 110 formed therein; attaching a second substrate 200 having a thermal expansion coefficient different from that of the first substrate 100 to the bottom of the first substrate 100 to manufacture a mask 400; and heating the mask 400.
[0043] Figure 1 FIG. 1 is a diagram showing a step of attaching a second substrate 200 having a different thermal expansion coefficient under the first substrate 100 according to an embodiment of the present invention.
[0044] First, provide Figure 1 As shown in (A), the first substrate 100 is formed of metal.
[0045] The metal forming the first substrate 100 can be, for example, composed of any one selected from beryllium, iron, nickel, chromium, tungsten, cobalt, molybdenum, tin (Sn), zinc-titanium (Zn-Ti), aluminum (Al), tungsten carbide and platinum, or an alloy of two or more thereof.
[0046] Alternatively, preferably, the metal forming the first substrate 100 is composed of beryllium, or an alloy of beryllium and any one or more selected from iron, nickel, chromium, tungsten, cobalt, molybdenum, tin, zinc titanium, aluminum, tungsten carbide and platinum.
[0047] Here, if we look at the physical properties of beryllium, its specific gravity is about 0.7 times that of aluminum and about 0.23 times that of iron. Its rigidity is more than 50% higher than that of steel, and it is lighter and harder than titanium. In addition, when beryllium is used, etching equipment used in conventional semiconductor equipment can be applied to manufacture FMMs. Due to the characteristics of the material, it can be reused after cleaning. Furthermore, since it is about 0.7 times lighter than the conventionally used invar, it can also prevent the phenomenon of pattern destruction due to sagging of the mask.
[0048] On the other hand, the first substrate 100 can be made of the aforementioned metal or metal alloy by rolling. For example, when beryllium is used, the thickness of the metal film can be made to be approximately 10 μm to 20 μm.
[0049] Then, if Figure 1 As shown in (B), the second substrate 200 is arranged under the first substrate 100, and the second substrate 200 having a thermal expansion coefficient different from that of the first substrate 100 is attached to the lower surface of the first substrate 100.
[0050] Figure 2 is a bottom view of the second substrate 200, Figure 3 It is a bottom view showing a state where the second substrate 200 is attached to the first substrate 100 .
[0051] Reference Figure 2 as well as Figure 3, the second substrate 200 may be formed with a predetermined thickness and form an opening portion 210 exposing the pattern of the first holes 110 of the first substrate 100. Therefore, when the second substrate 200 is attached below the first substrate 100, when viewed from the direction of the second substrate 200 ( Figure 3 ) can expose the first hole 110 of the first substrate 100 through the opening portion 210 of the second substrate 200.
[0052] On the other hand, the thermal expansion coefficient of the second substrate 200 may be different from that of the first substrate 100, and the thermal expansion coefficient of the first substrate 100 may be greater than that of the second substrate 200. That is, the thermal expansion coefficient of the second substrate 200 may be smaller than that of the first substrate 100.
[0053] This is to generate the following when the OLED mask 400 in the form of the first substrate 100 and the second substrate 200 being attached is heated. Figure 4 A bend that bulges upward as shown or a “⌒”-shaped warpage.
[0054] The following [Table 1] shows the thermal expansion coefficients of metals and various materials.
[0055] [Table 1]
[0056] Material Thermal expansion coefficient (μm / m℃) silicon 2.6～4.0 Silicon Nitride 2.5～4.0 Silicon oxide 0.5～1.0 Yin Gang 1.2 Super Invar 0.6 Iron, Beryllium 11.0 copper 17.0 aluminum 23.0
[0057] As shown in [Table 1], for example, when the first substrate 100 is made of beryllium and the second substrate 200 is made of silicon (Si), the thermal expansion coefficient of beryllium is approximately 11 μm / m°C, and the thermal expansion coefficient of silicon is equivalent to approximately 2.6 to 4 μm / m°C.
[0058] Therefore, since the thermal expansion coefficient of the first substrate 100 located above is larger than that of the second substrate 200 located below, the first substrate 100 located above expands more than the second substrate 200 during thermal expansion, so that the OLED mask 400 may have an upwardly convex shape.
[0059] If the OLED mask 400 is warped in this way, the OLED mask 400 can be more closely attached to a TFT (Thin Film Transistor) substrate (not shown) located thereover, and sagging due to the weight of the OLED mask 400 can be prevented.
[0060] on the other hand, Figure 5 It is enlarged to show Figure 4 FIG. 4 is a side view of a partial area of a mask 400 for an OLED.
[0061] Reference Figure 5 As described above, a plurality of first holes 110 are formed in the first substrate 100 of the OLED mask 400, and the openings 210 are formed in the second substrate 200 in a pattern corresponding to the first holes 110. Therefore, when viewed from below, the first holes 110 above are exposed through the openings 210 of the second substrate 200.
[0062] In this case, as described above, when the OLED mask 400 is heated, the deformation rates due to thermal expansion of the pattern region A and the non-pattern region B in the first substrate 100 where the first hole 110 is formed may be different.
[0063] For example, the deformation rate may be large in the pattern region A due to the formation of a plurality of first holes 110, and the deformation rate may be small in the non-pattern region B. Therefore, when the OLED mask 400 is heated, the pattern region A may be deformed in a convex shape upward as shown by the dotted line (in the drawings, the deformation is exaggerated for convenience of explanation). On the contrary, the deformation may be relatively small in the non-pattern region B.
[0064] Therefore, when the OLED mask 400 is brought into close contact with a TFT (Thin Film Transistor) substrate (not shown) located thereon, the pattern region A has a more convex shape toward the upper side, so that the pattern region A can be brought into close contact with the TFT substrate more effectively.
[0065] On the other hand, when the OLED mask 400 according to the present invention is repeatedly used, the warpage degree of the OLED mask 400 may change after one process is completed. In this case, in order to adjust the warpage degree of the OLED mask 400 to a desired level, a step of applying tensile stress or compressive stress to the OLED mask 400 by evaporating a thin film (not shown) on at least one of the upper surface of the first substrate 100 and the lower surface of the second substrate 200 may be further included.
[0066] That is, a thin film may be deposited on at least one of the upper surface of the first substrate 100 and the lower surface of the second substrate 200, and stress may be applied by the thin film to cause warpage of the OLED mask 400 and adjust the warpage degree of the OLED mask 400 to a desired level.
[0067] In this case, when a thin film is deposited on the upper surface of the first substrate 100, stress should be applied to form a convex shape toward the upper side, so that the thin film is deposited in a manner that compressive stress can be applied. Conversely, when a thin film is deposited on the lower surface of the second substrate 200, stress should be applied to form a convex shape toward the upper side, so that the thin film is deposited in a manner that tensile stress can be applied.
[0068] On the other hand, when the OLED mask 400 is bent into a convex shape upward, the area above the OLED mask 400 is wider than the area below. Therefore, when stress is applied by vapor depositing a thin film, it is preferred to vapor deposit the thin film on the wider area of the OLED mask 400, that is, on the first substrate 100.
[0069] In this way, when the evaporated film applies tensile stress or compressive stress to the OLED mask 400, the tensile stress or compressive stress can be applied by adjusting at least one of the type of process gas supplied, the supply amount of the process gas, the supply speed of the process gas, the intensity of the voltage applied to generate plasma, the pressure in the chamber of the evaporated film, and the thickness of the evaporated film.
[0070] The above description is made with reference to the preferred embodiments of the present invention, and those skilled in the art can make various modifications and changes to the present invention without departing from the concept and scope of the present invention as described in the attached claims. Therefore, if the implementation of the modification basically includes the constituent elements of the claims of the present invention, it should be deemed to be included in the technical scope of the present invention.
Claims
1. A method for manufacturing a mask for OLED, characterized in that: include: providing a first substrate formed of metal having a plurality of first holes formed therein; The step of attaching a second substrate having a thermal expansion coefficient different from that of the first substrate to the underside of the first substrate to manufacture a mask; as well as The step of heating the mask.
2. The method for manufacturing an OLED mask according to claim 1, wherein: The first substrate has a greater thermal expansion coefficient than the second substrate.
3. The method for manufacturing an OLED mask according to claim 1, wherein: The first substrate is composed of any one selected from beryllium, iron, nickel, chromium, tungsten, cobalt, molybdenum, tin, zinc-titanium, aluminum, tungsten carbide and platinum, or an alloy of two or more thereof.
4. The method for manufacturing an OLED mask according to claim 1, wherein: The first substrate is made of beryllium, or an alloy of the beryllium and at least one selected from the group consisting of iron, nickel, chromium, tungsten, cobalt, molybdenum, tin, zinc-titanium, aluminum, tungsten carbide, and platinum.
5. The method for manufacturing an OLED mask according to claim 1, wherein: In the step of heating the mask, The mask is bent into a convex shape toward upward.
6. The method for manufacturing an OLED mask according to claim 1, wherein: The OLED mask manufacturing method further includes: A step of applying tensile stress or compressive stress to the mask by depositing a thin film on at least one of the upper surface of the first substrate and the lower surface of the second substrate.
7. The method for manufacturing an OLED mask according to claim 6, characterized in that: In the step of applying tensile stress or compressive stress to the mask by evaporating the thin film, Tensile stress or compressive stress is applied by adjusting any one of the type of process gas supplied, the supply amount of the process gas, the supply speed of the process gas, the intensity of the voltage applied to generate plasma, the pressure in the chamber, and the thickness of the deposited film.
8. A mask for OLED, characterized in that: have: a first substrate formed of metal having a plurality of first holes formed therein; and The second substrate is disposed below the first substrate and has a thermal expansion coefficient different from that of the first substrate.
9. The OLED mask according to claim 8, characterized in that: The mask is formed to be curved in a convex shape toward the upper side.
10. The OLED mask according to claim 8, characterized in that: A thin film is further provided on at least one of the upper surface of the first substrate and the lower surface of the second substrate.