Mask cleaning method

Abstract

The invention relates to a mask cleaning method. The mask cleaning method includes: a first operation of cleaning a mask using a mask cleaning composition, in which the mask cleaning composition for cleaning a deposition mask includes a solvent having a Hansen solubility parameter distance Ra1 of 7.35 (MPa) 1 / 2 or less, the Hansen solubility parameter distance Ra1 being represented by the following equation: [equation] Ra1 = {4 * (17.9-[delta] D) 2 + (9.9-[delta] P) 2 + (7.4-[delta] H) 2} 1 / 2, [delta] D (MPa) 1 / 2 represents a dispersion force term of the solvent, [delta] P (MPa) 1 / 2 represents a polarity term of the solvent, and [delta] H (MPa) 1 / 2 represents a hydrogen bond force term of the solvent.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0124996 filed in the Korean Intellectual Property Office on September 19, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] One or more embodiments relate to a mask cleaning composition for cleaning a deposition mask, a mask cleaning method, and a method of manufacturing a display device. Background Art

[0004] The display device displays an image based on display data. The display device provides an image by using a light emitting diode. The applications and structures of a plurality of display devices have been diversified, and a structure that is bent from a flat state to a selectable angle is also being developed.

[0005] In order to display an image, a display device may include pixels in a certain pattern. The pixels may include multiple layers including an emissive layer. These layers may be arranged on a substrate in different patterns depending on their type. Summary of the invention

[0006] The embodiment provides a mask cleaning composition that ensures sufficient solubility of organic substances remaining on a mask after a deposition process and has a small surface tension so as to remain on the mask surface in a small amount.

[0007] Each layer of the display device can be formed by spraying a deposition material onto a mask assembly having an opening corresponding to a pattern desired to be formed on the substrate. The mask assembly can be cleaned using a cleaning solution to remove deposition material remaining on the mask assembly that does not pass through the opening. For example, the cleaning solution may remain on the surface of the mask assembly. The residual cleaning solution may deteriorate the deposition quality, such as generating gas in a subsequent deposition process using the mask assembly.

[0008] However, the embodiments are not limited to the embodiments described herein.The above and other embodiments will become more apparent to those of ordinary skill in the art to which the present disclosure pertains by referring to the detailed description of the present disclosure given below.

[0009] According to one or more embodiments, the mask cleaning composition for cleaning a deposition mask may include a composition having a viscosity of 7.35 (MPa) 1 / 2 or smaller Hansen solubility parameter distance R a1 The Hansen solubility parameter of the solvent is R a1 It is expressed by the following equation.

[0010] [Equation]

[0011] R a1 ={4×(17.9-δD) 2 +(9.9-δP) 2 +(7.4-δH) 2} 1 / 2

[0012] In the equation, δD(MPa) 1 / 2 represents the dispersion force term of the solvent, δP (MPa) 1 / 2 represents the polarity term of the solvent, and δH (MPa) 1 / 2 represents the hydrogen bonding term of the solvent.

[0013] The δD value of the solvent may be about 14.9 (MPa) 1 / 2 To about 20.9 (MPa) 1 / 2 In the range of , the δP value of the solvent is about 6.9 (MPa) 1 / 2 To about 12.9 (MPa) 1 / 2 and the δH value of the solvent is about 4.4 (MPa) 1 / 2 To about 10.4 (MPa) 1 / 2 within the range.

[0014] The solvent may have a surface tension of about 36 mN / m or less.

[0015] The mask cleaning composition may have a boiling point of about 176° C. or higher.

[0016] The solvent includes an amide compound, and the amide compound may include at least one selected from N,N-diethylformamide, N,N-dimethylpropionamide, N,N-diethylacetamide, N-n-butylacetamide, N,N-dimethylisobutyramide, N-ethylpropionamide and N-methylbutyramide.

[0017] The solvent may include a compound that is not reproductively toxic.

[0018] According to one or more embodiments, the mask cleaning method may include a first operation of cleaning the mask using a mask cleaning composition, wherein the mask cleaning composition may include a molten metal having a viscosity of 7.35 (MPa) 1 / 2 or smaller Hansen solubility parameter distance R a1 The Hansen solubility parameter of the solvent is R a1 It is expressed by the following equation.

[0019] [Equation]

[0020] R a1 ={4×(17.9-δD)2 +(9.9-δP) 2 +(7.4-δH) 2} 1 / 2

[0021] In the equation, δD(MPa) 1 / 2 represents the dispersion force term of the solvent, δP (MPa) 1 / 2 represents the polarity term of the solvent, and δH (MPa) 1 / 2 represents the hydrogen bonding term of the solvent.

[0022] The δD value of the solvent is about 14.9 (MPa) 1 / 2 To about 20.9 (MPa) 1 / 2 In the range of , the δP value of the solvent is about 6.9 (MPa) 1 / 2 To about 12.9 (MPa) 1 / 2 In the range of , and the δH value of the solvent is about 4.4 (MPa) 1 / 2 To about 10.4 (MPa) 1 / 2 within the range.

[0023] The solvent may have a surface tension of 36 mN / m or less.

[0024] The mask cleaning composition may have a boiling point of 176° C. or higher.

[0025] The solvent may include an amide compound, and the amide compound may include at least one selected from N,N-diethylformamide, N,N-dimethylpropionamide, N,N-diethylacetamide, N-n-butylacetamide, N,N-dimethylisobutyramide, N-ethylpropionamide and N-methylbutyramide.

[0026] The first operation may be performed under conditions in a temperature range of about 40°C to about 60°C.

[0027] The first operation may be performed by bringing the mask cleaning composition into contact with the mask by using a spray method or a dipping method.

[0028] The mask cleaning method may further include at least one of a second operation of cleaning the mask by using ultrapure water, a third operation of cleaning the mask by using alcohol, and a fourth operation of drying the mask.

[0029] According to one or more embodiments, a method for manufacturing a display device may include: arranging a mask to face a substrate; aligning the mask and the substrate; supplying a deposition material from a deposition source facing the mask so that the deposition material is deposited on the substrate; and cleaning the mask using a mask cleaning composition, wherein the mask cleaning composition may include a film having a viscosity of 7.35 (MPa) 1 / 2 or smaller Hansen solubility parameter distance R a1 The Hansen solubility parameter of the solvent is R a1 It is expressed by the following equation:

[0030] [Equation]

[0031] R a1 ={4×(17.9-δD) 2 +(9.9-δP) 2 +(7.4-δH) 2} 1 / 2

[0032] In the equation, δD(MPa) 1 / 2 represents the dispersion force term of the solvent, δP (MPa) 1 / 2 represents the polarity term of the solvent, and δH (MPa) 1 / 2 represents the hydrogen bonding term of the solvent.

[0033] The δD value of the solvent is about 14.9 (MPa) 1 / 2 To about 20.9 (MPa) 1 / 2 In the range of , the δP value of the solvent is about 6.9 (MPa) 1 / 2 To about 12.9 (MPa) 1 / 2 In the range of , and the δH value of the solvent is about 4.4 (MPa) 1 / 2 To about 10.4 (MPa) 1 / 2 within the range.

[0034] The solvent may have a surface tension of about 36 mN / m or less.

[0035] The mask cleaning composition may have a boiling point of about 176° C. or higher.

[0036] The solvent may include an amide compound, and the amide compound may include at least one selected from N,N-diethylformamide, N,N-dimethylpropionamide, N,N-diethylacetamide, N-n-butylacetamide, N,N-dimethylisobutyramide, N-ethylpropionamide and N-methylbutyramide.

[0037] The solvent may include a compound that is not reproductively toxic. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other aspects, features and advantages of certain embodiments will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0039] Figure 1 is a schematic plan view of a display device according to an embodiment;

[0040] Figure 2 It is along Figure 1 A schematic cross-sectional view taken along line II-II';

[0041] Figure 3 is a schematic cross-sectional view illustrating a method of manufacturing a display device and a mask cleaning method according to an embodiment;

[0042] Figure 4 is a three-dimensional (3D) graph showing the distribution of solvents according to Hansen solubility parameters and Hansen solubility parameter spheres; and

[0043] Figure 5A , Figure 5B , Figure 5C , Figure 5D and Figure 5E is a graph showing the change in brightness over time of a display device manufactured using a mask cleaned using Material X or the mask cleaning composition according to an embodiment. DETAILED DESCRIPTION

[0044] In the following description, many specific details are listed for the purpose of explanation to provide a thorough understanding of various embodiments or implementations of the present invention. As used herein, "embodiment" and "implementation" are interchangeable words and are non-limiting examples of the devices or methods disclosed herein. However, it is obvious that various embodiments can be implemented without these specific details or with one or more equivalent arrangements. Here, various embodiments do not have to be exclusive and must limit the disclosed content. For example, the specific shape, configuration and characteristics of an embodiment can be used or implemented in another embodiment.

[0045] Unless otherwise specified, the illustrated embodiments should be understood to provide features of the present invention. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions and / or aspects of the various embodiments, etc. (hereinafter individually or collectively referred to as "elements") may be combined, separated, interchanged and / or rearranged in other ways without departing from the scope of the present invention.

[0046] The use of cross-hatching and / or shading in the figures is generally provided to clarify the boundaries between adjacent elements. Therefore, unless otherwise specified, the presence or absence of cross-hatching or shading does not convey or indicate any preference or requirement for a specific material, material properties, size, ratio, commonality between illustrated elements and / or any other idiosyncrasies, attributes, characteristics, etc. of an element. In addition, in the figures, the size and relative size of the elements may be exaggerated for the purpose of clarity and / or description. When the embodiment can be implemented in different ways, a specific process sequence can be performed in a different order than described. For example, two processes described in succession can be performed substantially simultaneously or in an order opposite to the order of description. In addition, the same reference numerals represent the same elements.

[0047] When an element or layer is referred to as being "on" another element or layer, "connected to" or "coupled to" another element or layer, the element or layer may be directly on, connected to or coupled to the other element or layer, or there may be an intervening element or layer. However, when an element or layer is referred to as being "directly on" another element or layer, "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. For this reason, the term "connected" may refer to a physical connection, an electrical connection and / or a fluid connection, whether there are or are no intervening elements. In addition, the axis of the first direction DR1, the axis of the second direction DR2, and the axis of the third direction DR3 are not limited to three axes such as the X-axis, the Y-axis, and the Z-axis of a rectangular coordinate system, and may be interpreted in a broader sense. For example, the axis of the first direction DR1, the axis of the second direction DR2, and the axis of the third direction DR3 may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purpose of this disclosure, "at least one of A and B" may be understood to mean only A, only B, or any combination of A and B. In addition, “at least one of X, Y, and Z” and “at least one selected from the group consisting of X, Y, and Z” may be understood as any combination of only X, only Y, only Z, or two or more of X, Y, and Z. As used herein, the term “and / or” includes any combination or all combinations of one or more of the associated listed items.

[0048] Although the terms "first", "second", etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Therefore, without departing from the teachings of the present disclosure, the first element discussed below may be referred to as the second element.

[0049] Spatially relative terms such as "under," "beneath," "below," "lower," "on," "upper," "above," "higher," and "side" (e.g., in a "sidewall") may be used herein for descriptive purposes, and therefore, to describe the relationship of one element to another (or multiple) elements as shown in the figures. In addition to the orientations depicted in the figures, the spatially relative terms are intended to encompass different orientations of the device in use, operation, and / or manufacture. For example, if the device in the figures is turned over, elements described as "under" or "below" other elements or features would subsequently be oriented "on" the other elements or features. Thus, the term "under" can encompass both above and below orientations. Furthermore, the device can be in other orientations (e.g., rotated 90 degrees or other orientations), and therefore, the spatially relative descriptions used herein should be interpreted accordingly.

[0050] The terms used herein are for the purpose of describing specific embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "one (person / kind)" and "the (the)" as used herein are also intended to include plural forms. In addition, the terms "comprises / comprising" and "includes / including" when used in this specification indicate the presence of the features, integers, steps, operations, elements, components and / or their groups, but do not exclude the presence or increase of one or more other features, integers, steps, operations, elements, components and / or their groups. It is also noted that the terms "substantially", "approximately" and other similar terms as used herein are used as approximate terms and are not terms of degree, and therefore, these terms are used to explain the inherent deviations in the values ​​measured, calculated and / or provided that can be recognized by ordinary technicians in the field.

[0051] Various embodiments herein will be described with reference to cross-sectional views and / or exploded views, which are schematic diagrams of embodiments and / or intermediate structures. Therefore, variations in the shapes shown, for example due to manufacturing techniques and / or tolerances, are contemplated. Therefore, the embodiments disclosed herein need not be construed as being limited to the shapes shown in specific areas, but should include shape deviations that arise, for example, during the manufacturing process. In this way, the areas shown in the figures may be schematic in nature, and the shapes of these areas may not reflect the actual shapes of the areas of the device, and therefore need not be intended to be restrictive.

[0052] According to the practice in the art, some embodiments are described and shown in the form of functional blocks, units and / or modules in the accompanying drawings. It will be understood by those skilled in the art that these blocks, units and / or modules are physically implemented by electronic (or optical) circuits such as logic circuits, discrete components, microprocessors, hard-wired circuits, storage elements and wiring connections, and they can be formed using semiconductor-based manufacturing techniques or other manufacturing techniques. In the case where blocks, units and / or modules are implemented by microprocessors or other similar hardware, they can be programmed and controlled using software (e.g., microcode) to perform the various functions discussed herein and can be selectively driven by firmware and / or software. It is also considered that each block, unit and / or module can be implemented by dedicated hardware, or as a combination of dedicated hardware to perform some functions and processors (e.g., one or more programmed microprocessors and related circuits) to perform other functions. In addition, without departing from the scope of the present invention, each block, unit and / or module of some embodiments can be physically separated into two or more interactive and discrete blocks, units and / or modules. Furthermore, the blocks, units and / or modules of some embodiments may be physically combined into more complex blocks, units and / or modules without departing from the scope of the invention.

[0053] In the case where a certain embodiment can be implemented in different ways, a specific process sequence can be performed in a different order than described. For example, two processes described in succession can be performed substantially simultaneously or in a reverse order to the described order.

[0054] Figure 1 is a schematic plan view of a display device 20 according to the embodiment. Figure 2 It is along Figure 1 Schematic cross-sectional view taken along line II-II'.

[0055] refer to Figure 1 and Figure 2 , in the display device 20 , a display area DA and a non-display area NDA surrounding the display area DA may be defined on the substrate 21 .

[0056] The organic light emitting device (OLED) 28 may be arranged in the display area DA. For example, a power wiring may be arranged in the non-display area NDA. The pad portion C may also be arranged in the non-display area NDA. Figure 1 , the display area DA is shown to have a substantially rectangular shape. However, the embodiment is not limited thereto, and the shape of the display area DA may be modified in various ways. A deposition material pattern may be arranged in the display area DA.

[0057] The display device 20 may include a display substrate D, an intermediate layer 28 - 2 disposed on the display substrate D, and an opposite electrode 28 - 3 disposed on the intermediate layer 28 - 2. The display device 20 may include a thin film encapsulation layer E formed on the opposite electrode 28 - 3.

[0058] The display substrate D may include a substrate 21 , a thin film transistor TFT, a through layer 27 , and a pixel electrode 28 - 1 .

[0059] The substrate 21 may be formed of a plastic material, or may be formed of a metal material such as stainless steel (SUS) or titanium (Ti). In another example, the substrate 21 may be formed of polyimide (PI).

[0060] A thin film transistor TFT may be formed on the substrate 21 , a through layer 27 may be formed to cover the thin film transistor TFT, and an OLED 28 may be formed on the through layer 27 .

[0061] A buffer layer 22 made of an organic compound and / or an inorganic compound may be further formed on the upper surface of the substrate 21, and the buffer layer 22 may include silicon oxide (SiO x ) or silicon nitride (SiN x ).

[0062] An active layer 23 arranged in a certain pattern may be formed on the buffer layer 22 and may be buried by the gate insulating layer 24. The active layer 23 may include a source region 23-1 and a drain region 23-3, and may further include a channel region 23-2 between the source region 23-1 and the drain region 23-3.

[0063] The active layer 23 may include various materials. For example, the active layer 23 may include an inorganic semiconductor material such as amorphous silicon or crystalline silicon. As another example, the active layer 23 may include an oxide semiconductor. As another example, the active layer 23 may include an organic semiconductor material.

[0064] The active layer 23 may be formed by forming an amorphous silicon layer on the buffer layer 22, by crystallizing the amorphous silicon layer to form a polysilicon layer, and by patterning the polysilicon layer. The source region 23-1 and the drain region 23-3 of the active layer 23 may be doped with impurities according to the type of the thin film transistor TFT, such as a driving transistor and a switching transistor.

[0065] A gate electrode 25 overlapping the active layer 23 and an interlayer insulating layer 26 burying / covering the gate electrode 25 may be formed on the upper surface of the gate insulating layer 24. A contact hole H1 may be formed in (or through) the interlayer insulating layer 26 and the gate insulating layer 24, and a source electrode 27-1 and a drain electrode 27-2 may be formed on the interlayer insulating layer 26 so that the source electrode 27-1 and the drain electrode 27-2 may contact the source region 23-1 and the drain region 23-3, respectively, through the contact hole H1.

[0066] The through layer 27 may be formed on the thin film transistor TFT formed as described above, and the pixel electrode 28-1 of the OLED 28 may be formed on the through layer 27. The pixel electrode 28-1 may contact the drain electrode 27-2 of the thin film transistor TFT through the through hole H2 formed in the through layer 27 (or through the through layer 27). The through layer 27 may be formed of an inorganic material and / or an organic material, and may be formed as a single layer or multiple layers. The through layer 27 may be formed as a planarization layer so that the upper surface of the through layer 27 may be flat, and has nothing to do with the unevenness of the lower layer below the through layer 27. In another example, the through layer 27 may be formed as an uneven layer according to the unevenness of the lower layer below the through layer 27.

[0067] After forming the pixel electrode 28 - 1 on the through layer 27 , a pixel defining layer 29 may be formed of an organic and / or inorganic material to cover the through layer 27 and a portion of the pixel electrode 28 - 1 , and may be opened (or removed) to expose the pixel electrode 28 - 1 .

[0068] The intermediate layer 28-2 and the opposing electrode 28-3 may be formed on the pixel electrode 28-1. According to an embodiment, the opposing electrode 28-3 may be formed on the entire surface of the display substrate D. For example, the opposing electrode 28-3 may be formed on the intermediate layer 28-2 and the pixel defining layer 29. The pixel electrode 28-1 may be used as an anode, and the opposing electrode 28-3 may be used as a cathode. In another example, the pixel electrode 28-1 may be used as a cathode, and the opposing electrode 28-3 may be used as an anode.

[0069] The intermediate layer 28-2 may include an organic emission layer. As another example, the intermediate layer 28-2 may include an organic emission layer, and may further include at least one of a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (EIL). The embodiment is not limited thereto, and in addition to the organic emission layer, the intermediate layer 28-2 may further include various other functional layers.

[0070] The pixel electrode 28 - 1 and the opposite electrode 28 - 3 may be spaced apart from each other by the intermediate layer 28 - 2 , and voltages of opposite polarities are applied to the intermediate layer 28 - 2 , respectively, so that light emission may be performed in the organic emission layer.

[0071] The intermediate layer 28 - 2 may include the intermediate layer 28 - 2 , and the intermediate layer 28 - 2 may be formed in the display area DA. For example, the intermediate layers 28 - 2 may be spaced apart from each other and arranged in a certain pattern within the display area DA.

[0072] A unit pixel (e.g., a single unit pixel) may include sub-pixels, and the sub-pixels may emit light of various colors. For example, the sub-pixels may include sub-pixels that emit red light, green light, and blue light, respectively, or may include sub-pixels that emit red light, green light, blue light, and white light, respectively. The sub-pixels may each include a single intermediate layer 28-2.

[0073] The thin film encapsulation layer E may include an inorganic layer, or may include an inorganic layer and an organic layer.

[0074] The organic layer of the thin film encapsulation layer E may be formed of a polymer, and may be a single layer or a stacked layer formed of polyethylene terephthalate (PET), PI, polycarbonate (PC), epoxy resin, polyethylene, or polyacrylate.

[0075] The inorganic layer of the thin film encapsulation layer E may be a single layer or a stacked layer including oxide or nitride. For example, the inorganic layer may include SiN x 、Al 2 O 3 、SiO 2 and TiO 2 Any one of .

[0076] The uppermost layer exposed to the outside among the thin film encapsulation layer E may be formed of an inorganic layer to prevent moisture from penetrating (or permeating) into the OLED 28 .

[0077] Figure 3 2 is a schematic cross-sectional view illustrating a method of manufacturing a display device and a mask cleaning method according to an embodiment.

[0078] References Figure 1 and Figure 2 The various layers of the display device described may be formed on a substrate by a deposition process. The deposition process may be performed by a manufacturing device for a display device (eg, the deposition device 10).

[0079] The deposition apparatus 10 may include a chamber 11 providing a space for performing a deposition process and a deposition source 12 for performing deposition by spraying a deposition material. The deposition apparatus 10 may further include various components such as a pressure control unit, a magnetic force unit, and a scanning unit, but for convenience of description, Figure 3 These components are not shown in FIG.

[0080] In order to perform the deposition operation DS, a display substrate D, a mask M, and a deposition source 12 may be disposed in the chamber 11. For example, the display substrate D may be a process target, and disposing a deposition material in a specific pattern on the display substrate D may be the deposition operation DS. Therefore, the mask M may have an opening of a shape corresponding to the specific pattern, and may be disposed between the display substrate D and the deposition source 12.

[0081] In a case where the display substrate D, the mask M, and the deposition source 12 are disposed in the chamber 11, the deposition material may be ejected from the deposition source 12 toward the display substrate D. For example, some of the deposition material ejected from the deposition source 12 may pass through the openings formed in the mask M and may be disposed on the display substrate D. Thus, the deposition material may be disposed on the display substrate D in a pattern similar to the shape of the openings of the mask M.

[0082] According to an embodiment, the deposition source 12 may include Figure 2 The intermediate layer 28-2 includes a deposition material, and the deposition material can be sprayed onto the display substrate D to form Figure 2 Since the deposition material can be disposed on the display substrate D through the openings formed in a certain pattern in the mask M, Figure 2 The intermediate layer 28 - 2 disposed on the display substrate D may be arranged in a pattern similar to the openings of the mask M.

[0083] After performing the deposition operation DS, the deposition material that does not pass through the openings may remain on at least one surface of the mask M. Thereafter, in order to repeatedly perform a separate deposition process, it is necessary to remove the deposition material remaining on the mask M. For example, the mask M may be reused through a cleaning process.

[0084] The operation of cleaning the mask M may include a first operation S1 of cleaning the mask M using a first composition C1 , a second operation S2 of cleaning the mask M using a second composition C2 , a third operation S3 of cleaning the mask M using a third composition C3 , and a fourth operation S4 of drying the mask M.

[0085] In the first operation S1, the mask M may be cleaned using a first composition C1. The first composition C1 as a mask cleaning composition may include a solvent capable of dissolving a deposition material remaining on the mask M. The mask cleaning composition may be a mixture of a solvent and distilled water at a certain ratio.

[0086] Thereafter, in the second operation S2, the mask M having undergone the first operation S1 may be cleaned using a second composition C2. According to an embodiment, the second composition C2 may include deionized water or ultrapure water. According to another embodiment, the second composition C2 may include distilled water.

[0087] Afterwards, in the third operation S3, the mask M that has undergone the second operation S2 may be cleaned using the third composition C3. According to an embodiment, the third composition C3 may contain an alcohol. According to some embodiments, the alcohol of the third composition C3 may include methanol, ethanol, pentanol, 2-methyl-2-butanol, 3-methyl-2-butanol, n-propanol, isopropanol, butanol, isobutanol, 2-butanol, 2-methyl-2-propanol, hexanol, cyclohexanol, benzyl alcohol, propanol, isopropanol, ethylene glycol, propylene glycol, diethylene glycol, glycerol, dipropylene glycol, or any combination thereof.

[0088] In the fourth operation S4, the mask M having undergone the third operation S3 may be dried. Therefore, the fourth composition C4 may be air. According to an embodiment, in the fourth operation S4, the liquid remaining on the surface of the mask M may be removed using an air knife to dry the mask M.

[0089] According to some embodiments, the first operation S1, the second operation S2, the third operation S3, and the fourth operation S4 may be performed in a temperature range of about 40 degrees Celsius (° C.) to about 60 degrees Celsius (° C.) According to some embodiments, at least one of the second operation S2, the third operation S3, and the fourth operation S4 may be omitted.

[0090] exist Figure 3 , the first operation S1, the second operation S2, and the third operation S3 are shown to be performed using a dipping method. However, the embodiment is not limited thereto. According to another embodiment, at least one of the first to third operations may include a method of cleaning the mask M by various methods (such as a spraying method).

[0091] The first composition C1 used in the first operation S1 may be a mask cleaning composition, and may need to ensure sufficient solubility of the deposition material remaining on the mask M. Therefore, the first composition C1 may include a solvent for the deposition material.

[0092] In the case where the first composition C1 remains on the surface of the mask M after the first operation S1, there is a risk of deterioration in deposition quality in a separate deposition process using the mask M. Therefore, the first composition C1 may have a small surface tension so that the amount of the first composition C1 remaining on the mask surface may be reduced.

[0093] Figure 4 is a three-dimensional (3D) graph showing the distribution of solvents according to Hansen solubility parameters and Hansen solubility parameter spheres.

[0094] refer to Figure 4, Hansen solubility parameters may represent the degree to which two substances located in a 3D space defined by axes defined by δD, δH, and δP mix with each other by the distance between the two substances. Two substances that are close to each other in the 3D space may be substances that are easily mixed with each other. Two substances that are far away from each other may be substances that are difficult to mix with each other.

[0095] The axis δD may be the dispersion force axis of the material, the axis δP may be the polarity (or dipole energy) axis of the material, and the axis δH may be the hydrogen bonding force axis of the material.

[0096] The deposition material is shown as a sphere labeled 1. The cleaning composition used to remove the deposition material 1 from the mask surface may need to include a substance that is easily mixed with the deposition material 1, for example, a substance (or solvent) in which the deposition material 1 is easily dissolved. It is understood that as the substance approaches the Figure 4 , the substance has a large solubility for the deposition material 1. The distribution range of the substance that can be used as a solvent for the deposition material 1 is shown as a sphere with a third distance R3 as a radius. For example, the third material 3 located at the third distance R3 away from the deposition material 1 can be understood as one of the substances with the smallest solubility among the substances that can be used as a solvent for dissolving the deposition material 1. Since the second material 2 is located in the sphere, the distance between the second material 2 and the deposition material 1 is the second distance R2, and the second material 2 can be used as a solvent for dissolving the deposition material 1. Since the second distance R2 is less than the third distance R3, the second material 2 can be more suitable as a solvent for the deposition material 1 than the third material 3. Since the fourth material 4 is located outside the sphere, the distance between the fourth material 4 and the deposition material 1 is the fourth distance R4, and the fourth material 4 cannot be used as a solvent for dissolving the deposition material 1.

[0097] The Hansen solubility parameter distance can be expressed by the following Equation 1.

[0098] [Equation 1]

[0099]

[0100] Among them, R a It can represent the Hansen solubility parameter distance, and its unit can be (MPa) 1 / 2 ; δD can represent the dispersion force term of the material, and its unit can be (MPa) 1 / 2 ; δP can represent the polarity (or dipole energy) term of the material, and its unit can be (MPa) 1 / 2 ; and δH can represent the hydrogen bonding force term of the material, and its unit can be (MPa) 1 / 2For example, the second distance R2 may be a Hansen solubility parameter distance determined by a δD (or dispersion force) difference between the deposition material 1 and the second material 2, a δP (or polarity) difference between the deposition material 1 and the second material 2, and a δH (or hydrogen bonding force) difference between the deposition material 1 and the second material 2.

[0101] Therefore, as the difference in δD, δP, and δH between the two materials decreases, the Hansen solubility parameters move away from R a (i.e., between the two materials Figure 4 The distance in the 3D space shown) can be reduced. Therefore, the two materials can be easily mixed (or fused) with each other. Therefore, it may be appropriate to use one material as a solvent for another material.

[0102] In order to effectively remove the deposition material 1 remaining on the mask surface, the solubility of the mask cleaning composition to the deposition material 1 may be sufficiently large. In order to effectively remove the deposition material 1 remaining on the mask surface, the Hansen solubility parameter distance R between the deposition material 1 and the mask cleaning composition may be large enough. a Can be small enough. For example, in order to reduce the amount of the mask cleaning composition remaining on the mask surface, the surface tension of the mask cleaning composition can be small. Such a mask cleaning composition can be implemented by including one or more materials in the materials shown in Table 1 below. However, the embodiment is not limited to the materials disclosed in Table 1 below.

[0103] [Table 1]

[0104] Material Name Surface tension (mN / m) <![CDATA[δD(MPa) 1 / 2 ]]> <![CDATA[δP9(MPa) 1 / 2 ]]> <![CDATA[δH(MPa )1 / 2 ]]> X 40.1 17.9 9.9 7.4 N,N-Diethylformamide 27.8 16.7 11.1 7.7 N,N-Dimethylpropionamide 26.5 16.8 10.4 7.6 N,N-Diethylacetamide 27.3 16.7 9.5 5.4 N-butylacetamide 27.9 17.0 11.0 8.8 N,N-Dimethylisobutylamide 26.1 16.6 9.1 6.4 N-Ethylpropionamide 26.0 16.9 12.3 8.9 N-Methylbutyramide 26.0 17.1 12.0 8.9

[0105] The material X as a comparative example for the present disclosure may be N-methylpyrrolidone (NMP). According to an embodiment, a mask cleaning composition having solubility in deposition material 1 similar to that of the material X according to the comparative example may be implemented.

[0106] The Hansen solubility parameter distance between material X and the mask cleaning composition can be expressed by Equation 2 below.

[0107] [Equation 2]

[0108]

[0109] Among them, R a1 The Hansen solubility parameter distance between the material X and the mask cleaning composition according to an embodiment may be represented by , and its unit may be (MPa) 1 / 2 .

[0110] In Equation 2, δD, δP, and δH may represent the dispersion force term, polarity term, and hydrogen bonding force term of the mask cleaning composition, respectively, and have (MPa)1 / 2 Unit of.

[0111] In Equation 2, 17.9 may be the value of the dispersion force term for material X and may be expressed in (MPa) 1 / 2 In units of 9.9, the polar term of material X can be expressed as (MPa). 1 / 2 The unit is expressed in MPa, and 7.4 can be the value of the hydrogen bonding force term of material X and can be expressed in MPa. 1 / 2 The unit is expressed as .

[0112] The values ​​of δD, δP and δH of the mask cleaning composition are respectively the same as δD (or 17.9 (MPa)) of material X. 1 / 2 ),δP(or 9.9(MPa) 1 / 2 ) and δH(or 7.4(MPa) 1 / 2 ) The difference between the respective values ​​can be within ±3.0 (MPa) 1 / 2 or smaller.

[0113] For example, the value of δD of the mask cleaning composition may be about 14.9 (MPa) 1 / 2 To about 20.9 (MPa) 1 / 2 The value of δP of the mask cleaning composition may be about 6.9 (MPa) 1 / 2 To about 12.9 (MPa) 1 / 2 The value of δH of the mask cleaning composition may be about 4.4 (MPa) 1 / 2 To about 10.4 (MPa) 1 / 2 within the range.

[0114] Therefore, the Hansen solubility parameter distance R between material X and the mask cleaning composition a1 Can be less than approximately exist Figure 4 In the 3D space shown in FIG, such a mask cleaning composition may be close to material X and may be close to deposition material 1, and deposition material 1 may be cleaned using material X. Therefore, the mask cleaning composition according to an embodiment may have a solubility (or cleaning power) for deposition material 1 similar to that of material X for deposition material 1.

[0115] The surface tension of the mask cleaning composition according to an embodiment may be less than the surface tension of the material X. For example, the surface tension of the mask cleaning composition may be 10% or more less than the surface tension of the material X. According to an embodiment, the surface tension of the mask cleaning composition may be about 36.0 mN / m or less. Therefore, such a mask cleaning composition has a smaller surface tension than the material X, and thus a small amount of residue may remain on the mask after the cleaning step.

[0116] The boiling point of the mask cleaning composition according to an embodiment may be about 176 degrees Celsius (° C.) or higher. Therefore, in a subsequent deposition process, the mask cleaning composition may not be vaporized and thus may not generate gas.

[0117] According to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) and the Material Safety Data Sheet (MSDS) of the Korean Occupational Safety and Health Agency according to GHS, material X (or N-methylpyrrolidone) may have reproductive toxicity (hazard statement H360). For example, according to the classification of GHS and MSDS, the mask cleaning composition according to the embodiment may not include reproductive toxic compounds. For example, the mask cleaning composition according to the embodiment may only include compounds without reproductive toxicity based on the classification of GHS and MSDS. For example, according to the classification of GHS and MSDS, all the substances except material X among the materials listed in Table 1 may not have reproductive toxicity.

[0118] Therefore, according to an embodiment, a mask cleaning composition can be provided, wherein the cleaning ability of the mask cleaning composition for the deposited material is similar to that of material X, since the surface tension is smaller than that of material X, the residual amount of the mask cleaning composition on the mask is smaller than the residual amount of material X, and compared with material X, the mask cleaning composition does not include reproductive toxicity.

[0119] FIG. 5A to FIG. 5E is a graph showing the change in brightness over time of a display device manufactured using a mask cleaned using Material X or the mask cleaning composition according to an embodiment.

[0120] FIG. 5A to FIG. 5E The brightness of the display device changing over time in the case of operation of the display device emitting light at a brightness of approximately 500 nits at room temperature is shown.

[0121] The first embodiment 100 shown in solid lines may be a comparative example of the present disclosure, and demonstrates the brightness of a display device manufactured using a mask cleaned with material X. The second embodiment 200 shown in another solid line demonstrates the brightness of a display device manufactured using a mask cleaning composition according to an embodiment. The first trend 100′ shown in dashed lines overlapping the first embodiment 100 may be a trend line of the first embodiment 100. The second trend 200′ shown in dashed lines overlapping the second embodiment 200 may be a trend line of the second embodiment 200′.

[0122] exist FIG. 5A to FIG. 5D In the above description, "luminance lifetime" refers to the reference Figure 1 and Figure 2 The brightness of a pixel (or sub-pixel) of a display device (e.g. Figure 2The time required for the brightness of OLED 28 in the display to drop to a certain percentage of the initial brightness (e.g., about 500 nits) is shown in the figure. In the graph, the X-axis may represent time, and the unit may be hours. In the figure, the Y-axis may represent brightness as a percentage (%) relative to the initial lighting brightness (e.g., about 500 nits).

[0123] Figure 5A A graph showing the brightness of a pixel of a display device changing over time is shown.

[0124] refer to Figure 5A , the decreasing slope of the first embodiment 100 may be greater than the decreasing slope of the second embodiment 200. For example, the brightness of the first embodiment 100 may be about 92.3% after 500 hours, the brightness of the second embodiment 200 may be about 94% after 500 hours, and the brightness of the second embodiment 200 may be greater than the brightness of the first embodiment 100.

[0125] Any brightness can be set as the threshold brightness Ls. According to an embodiment, the threshold brightness Ls may be about 93%. The time required for the first embodiment 100 (or the first trend 100') to reach the threshold brightness Ls may be defined as a first time t1. The first time t1 may be about 460 hours. The time required for the second embodiment 200 (or the second trend 200') to reach the threshold brightness Ls may be defined as a second time t2. The second time t2 may be about 613 hours.

[0126] Figure 5B A graph showing the brightness of a red sub-pixel of a pixel of a display device varying over time is shown.

[0127] refer to Figure 5B , the decreasing slope of the first embodiment 100 may be greater than the decreasing slope of the second embodiment 200. For example, the first brightness L1 (i.e., the brightness of the first embodiment 100 after 500 hours) may be about 97.2%, and the second brightness L2 (i.e., the brightness of the second embodiment 200 after 500 hours) may be about 98.2%. The second brightness L2 may be greater than the first brightness L1.

[0128] Figure 5C A graph showing the brightness of a green sub-pixel of a pixel of a display device varying over time is shown.

[0129] refer to Figure 5C , the decreasing slope of the first embodiment 100 may be greater than the decreasing slope of the second embodiment 200. For example, the first brightness L1 (i.e., the brightness of the first embodiment 100 after 500 hours) may be about 92.3%, and the second brightness L2 (i.e., the brightness of the second embodiment 200 after 500 hours) may be about 94.2%. The second brightness L2 may be greater than the first brightness L1.

[0130] Figure 5D A graph showing the brightness of a blue sub-pixel of a pixel of a display device varying over time is shown.

[0131] refer to Figure 5D , the decreasing slope of the first embodiment 100 may be greater than the decreasing slope of the second embodiment 200. For example, the first brightness L1 (i.e., the brightness of the first embodiment 100 after 500 hours) may be about 87.2%, and the second brightness L2 (i.e., the brightness of the second embodiment 200 after 500 hours) may be about 88.5%. The second brightness L2 may be greater than the first brightness L1.

[0132] like FIG. 5A to FIG. 5D , it is shown that, after the same period of time (e.g., 500 hours), the brightness of the display device according to the second embodiment 200 may be greater than the brightness of the display device according to the first embodiment 100. For example, it can be considered that, after the same period of time, the brightness of the display device manufactured using the mask cleaned by the mask cleaning composition according to the embodiment may be greater than the brightness of the display device manufactured using the mask cleaned by the material X.

[0133] like Figure 5A , the time period (or brightness lifetime) required to reach the same brightness (e.g., about 93%) in the second embodiment 200 may be longer than the time period required to reach the same brightness (e.g., about 93%) in the first embodiment 100. For example, it can be considered that the brightness lifetime of a display device manufactured using a mask cleaned with the mask cleaning composition according to the embodiment may be longer than the brightness lifetime of a display device manufactured using a mask cleaned with material X.

[0134] Figure 5E is a graph showing how the distance between the light from the display device and the position of the original light on the color coordinate system changes over time. Figure 5E In , the X-axis can represent time, and the unit can be hours. Figure 5E In the figure, the Y axis may represent a separation distance Δu'v' in the color coordinate system, and the separation distance Δu'v' is an arbitrary value.

[0135] Under the same conditions, the color of light emitted by a pixel of a display device can change gradually over time. The separation distance in the color coordinate system represents the degree of distance of the color of light from another color, for example, the degree of difference. Figure 5E In the context of color life, "color lifetime" refers to the time required for the position of light emitted by a pixel (or sub-pixel) of a display device on a color coordinate system to be a certain distance away from the position of the light originally emitted on the color coordinate system, such as the time required for the color of the light to change.

[0136] refer to Figure 5E , after 500 hours, the separation distance of the first embodiment 100 may be about 0.006, and the separation distance of the second embodiment 200 may be about 0.0045. Figure 5D , the separation distance of the first embodiment 100 may be greater than the separation distance of the second embodiment 200 .

[0137] Any separation distance may be set as the critical separation distance Ds. According to an embodiment, the critical separation distance Ds may be about 0.01. The time required for the first trend 100' to reach the critical separation distance Ds may be defined as a first time t1. The first time t1 may be about 832 hours. The time required for the second trend 200' to reach the critical separation distance Ds may be defined as a second time t2. The second time t2 may be about 1120 hours.

[0138] Therefore, after the same time (e.g., 500 hours) has passed, the color of light emitted by the pixels of the display device in the second embodiment 200 may differ less than the color of light originally emitted in the first embodiment 100. For example, it can be considered that after the same period of time has passed, the color of light emitted by a display device manufactured using a mask cleaned with the mask cleaning composition according to the embodiment may differ less than the color of light emitted by a display device manufactured using a mask cleaned with material X.

[0139] For example, the time required to reach the same separation distance (e.g., about 0.01) in the color coordinate system in the second embodiment 200 may be longer than the time required in the first embodiment 100. For example, it can be considered that the color life of a display device manufactured using a mask cleaned with the mask cleaning composition according to an embodiment may be longer than the color life of a display device manufactured using a mask cleaned with material X.

[0140] According to the above described embodiments, the mask cleaning composition can be implemented to maintain the cleaning power of the organic deposits remaining on the mask assembly, and has a small surface tension, so that a small amount remains on the surface of the mask assembly after cleaning. For example, by implementing a mask cleaning method and a display device manufacturing method using such a mask cleaning composition, a display device with improved panel life can be manufactured. The present disclosure is not limited to this effect.

[0141] In summarizing the detailed description, it will be appreciated by those skilled in the art that many changes and modifications may be made to the embodiments of the present invention without substantially departing from the principles and spirit and scope of the present disclosure. Therefore, the disclosed embodiments are used only in a general and descriptive sense and are not intended to be limiting.

Claims

1. A mask cleaning method, wherein: The mask cleaning method comprises: a first operation of cleaning the mask using a mask cleaning composition, Wherein, the mask cleaning composition comprises a 1 / 2 or smaller Hansen solubility parameter distance R a1 The Hansen solubility parameter of the solvent is R a1 It is expressed by the following equation: Equation R a1 ={4×(17.9-δD) 2 +(9.9-δP) 2 +(7.4-δH) 2 } 1 / 2 Among them, δD (MPa) 1 / 2 represents the dispersion force term of the solvent, δP (MPa) 1 / 2 represents the polarity term of the solvent, and δH (MPa) 1 / 2 represents the hydrogen bonding term of the solvent.

2. The mask cleaning method according to claim 1, wherein: The δD value of the solvent is 14.9 (MPa) 1 / 2 To 20.9 (MPa) 1 / 2 within the range of The δP value of the solvent is 6.9 (MPa) 1 / 2 To 12.9 (MPa) 1 / 2 within the scope of The δH value of the solvent is 4.4 (MPa) 1 / 2 To 10.4 (MPa) 1 / 2 within the range.

3. The mask cleaning method according to claim 1, wherein: The solvent has a surface tension of 36 mN / m or less.

4. The mask cleaning method according to claim 1, wherein: The mask cleaning composition has a boiling point of 176° C. or higher.

5. The mask cleaning method according to claim 1, wherein: The solvent includes an amide compound, and The amide compound includes at least one selected from N,N-diethylformamide, N,N-dimethylpropionamide, N,N-diethylacetamide, N-n-butylacetamide, N,N-dimethylisobutyramide, N-ethylpropionamide and N-methylbutyramide.

6. The mask cleaning method according to claim 1, wherein: The solvent includes a compound that is not reproductively toxic.

7. The mask cleaning method according to claim 1, wherein: The first operation is performed under the condition of a temperature range of 40°C to 60°C.

8. The mask cleaning method according to claim 1, wherein: The first operation is performed by bringing the mask cleaning composition into contact with the mask by using a spray method or a dipping method.

9. The mask cleaning method according to claim 1, wherein: The mask cleaning method further comprises at least one of the following operations: The second operation of cleaning the mask by using ultrapure water a third operation of cleaning the mask by using alcohol; and A fourth operation is to dry the mask.

Images