Production Method for Opening Morphology of OLED Metal Mask

Abstract

The present invention provides a method for producing the opening topography of an OLED metal mask plate, which relates to the technical field of mask plate production. The method for producing the opening topography of the OLED metal mask plate comprises the following steps: feeding a mask plate substrate, cleaning the mask plate substrate with RO pure water, pickling the cleaned mask plate substrate; etching the mask plate substrate with an etching solution, wherein the etching solution comprises 40%-50% ferric chloride, 0.5%-1% hydrochloric acid, 0.5%-2% sodium octane sulfonate and 47%-59% water; alkali-washing the etched mask plate substrate, and performing water washing after alkali-washing; drying the mask plate substrate and discharging it. The technical effect that the graphic size required on the fine metal mask plate meets the standard is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of mask plate production, and more particularly, to a method for producing the opening morphology of an OLED metal mask plate. Background Art

[0002] Many film layer structures in organic light-emitting diodes (OLEDs) are formed by evaporation using a metal mask plate assembly (MFA). A complete set of metal mask plate assemblies (MFAs) usually consists of a mask plate frame (Frame), a fine metal mask (FMM, Fine Metal Mask), and an alignment mask (AlignMask). Among them, the quality of the fine metal mask (FMM) plays a decisive role in the evaporation effect of the film layer structure.

[0003] Currently, the fine metal mask is produced by a wet etching process. The area on the fine metal mask that is not protected by the dry film reacts with the etching substrate through a chemical solution to obtain the required pattern. However, in the existing technical solutions, during the etching process of the fine metal mask, there is an easy problem of corner loss after etching of acute-angle patterns, resulting in poor uniformity of the size (CD) of the etched required pattern (large and small hole phenomenon) and a smaller CD of the holes in the abnormal area, causing the evaporation size during the evaporation process at the client side not to meet the set size, and seriously leading to dark spot problems that affect the product quality. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for producing the opening morphology of an OLED metal mask plate to alleviate the technical problem that the size of the required pattern on the fine metal mask in the existing technology does not meet the standard.

[0005] In a first aspect, an embodiment of the present invention provides a method for producing the opening morphology of an OLED metal mask plate, including the following steps:

[0006] Loading the mask plate substrate, washing the mask plate substrate with RO pure water, and pickling the washed mask plate substrate;

[0007] Etching the mask plate substrate with an etching solution, where the etching solution includes 40%-50% ferric chloride, 0.5%-1% hydrochloric acid, 0.5%-2% sodium octane sulfonate, and 47%-59% water;

[0008] Alkaline washing the etched mask plate substrate, and then performing water washing after alkaline washing;

[0009] Drying the mask plate substrate and unloading it.

[0010] In combination with the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the temperature of the etching solution is between 24°C and 41°C.

[0011] In combination with the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the specific gravity of the sodium octane sulfonate is between 0.5% and 1.5%.

[0012] In combination with the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the specific gravity of the sodium octane sulfonate is between 0.8% and 1.2%.

[0013] In combination with the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the specific gravity of the sodium octane sulfonate is 1%.

[0014] In combination with the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the specific gravity of the hydrochloric acid is 0.5%.

[0015] In combination with the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the surface tension of the etching solution is between 20 and 25 mN / m.

[0016] In combination with the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the surface tension of the etching solution is between 22 and 24 mN / m.

[0017] In combination with the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the alkali washing solution uses an aqueous solution of 1% sodium hydroxide.

[0018] Beneficial effects:

[0019] The present invention provides a method for producing the opening morphology of an OLED metal mask plate, including the following steps: loading the mask plate substrate, washing the mask plate substrate with RO pure water, pickling the washed mask plate substrate; etching the mask plate substrate with an etching solution, the etching solution includes 40%-50% ferric chloride, 0.5%-1% hydrochloric acid, 0.5%-2% sodium octane sulfonate and 47%-59% water; alkali washing the etched mask plate substrate, followed by water washing after alkali washing; drying the mask plate substrate and unloading it.

[0020] Specifically, a fine metal mask plate is used in the production of OLED screens. During the production process of the fine metal mask plate, the mask plate substrate is loaded, and then the mask plate substrate is cleaned to remove the residual chemical solution on the mask plate substrate. Then, the mask plate substrate is pickled after cleaning to neutralize the residual alkali solution in the previous stage. Then, a water wash is carried out to remove the residual chemical solution and impurities. Then, the mask plate substrate is etched with an etching solution containing ferric chloride, hydrochloric acid, and sodium octane sulfonate to etch evaporation source openings on the mask plate substrate. After etching, the mask plate substrate is alkali-washed and then dried and unloaded. By adding sodium octane sulfonate to the etching solution, the etching solution can better enter every corner of the pre-etching area, especially the acute-angle area of the pre-etching area, so that the etching solution can etch comprehensively, ensuring that the sizes of the evaporation source openings after etching are uniform, thereby ensuring the production quality of OLEDs. Description of the Drawings

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 Schematic diagram of a partial opening of a metal mask plate produced by the production method of the opening morphology of an OLED metal mask plate provided in the embodiment of the present invention;

[0023] Figure 2 Schematic diagram of a partial opening of a metal mask plate produced by the prior art. Specific Embodiments

[0024] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0025] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0026] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0027] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The present invention will be further described in detail below through specific embodiments in conjunction with the drawings.

[0029] See Figure 1 and Figure 2 As shown, this embodiment provides a method for producing the opening morphology of an OLED metal mask plate, including the following steps: loading the mask plate substrate, cleaning the mask plate substrate with RO pure water, pickling the cleaned mask plate substrate; etching the mask plate substrate with an etching solution, the etching solution including ferric chloride, hydrochloric acid, and sodium octanesulfonate; alkali-washing the etched mask plate substrate, followed by water-washing after alkali-washing; drying the mask plate substrate and unloading it.

[0030] Specifically, the fine metal mask plate is used for the production of OLED screens. During the production process of the fine metal mask plate, the mask plate substrate is loaded, and then the mask plate substrate is cleaned to remove the residual liquid medicine on the mask plate substrate. Then, the mask plate substrate is pickled after cleaning to neutralize the residual alkali liquid in the previous stage. Then, it is washed with water once to remove the residual liquid medicine and impurities. Then, the mask plate substrate is etched with an etching solution containing ferric chloride, hydrochloric acid, and sodium octanesulfonate to etch evaporation source openings on the mask plate substrate. After etching, the mask plate substrate is alkali-washed and then dried and unloaded. By adding sodium octanesulfonate to the etching solution, the etching solution can better enter each corner of the pre-etching area, especially the acute-angle area of the pre-etching area, so that the etching solution can etch comprehensively, ensuring that the sizes of the evaporation source openings after etching are uniform, thus ensuring the production quality of OLEDs.

[0031] Among them, RO pure water is water filtered through a reverse osmosis membrane and has a high degree of purity.

[0032] Among them, in the existing production process, due to the surface tension of the liquid medicine in wet etching, the etching liquid medicine cannot enter each corner of the etching area evenly. Especially in the acute-angle area, the replacement of the liquid medicine is slower than that in the normal area. Therefore, the sizes of each evaporation source opening cannot be guaranteed to be exactly the same, resulting in etching missing corners. Thus, the dimensional (CD) uniformity of the required pattern (evaporation source opening) etched is poor (large and small holes), and the CD of the evaporation source opening in the abnormal area is smaller. During the subsequent evaporation process at the customer end, the evaporation size does not meet the set size, which may seriously lead to dark spot problems and reduce the product quality.

[0033] Among them, the temperature of the etching solution can be set to 24 °C, or the temperature of the etching solution can be set to 25 °C, or the temperature of the etching solution can be set to 27 °C, or the temperature of the etching solution can be set to 30 °C, or the temperature of the etching solution can be set to 32 °C, or the temperature of the etching solution can be set to 35 °C, or the temperature of the etching solution can be set to 40 °C, or the temperature of the etching solution can be set to 41 °C.

[0034] Among them, the alkali-washing solution uses an aqueous solution of 1% sodium hydroxide.

[0035] In an alternative solution of this embodiment, the etching solution includes 40%-50% ferric chloride, 0.5%-1% hydrochloric acid, 0.5%-2% sodium octanesulfonate, and 47%-59% water.

[0036] Specifically, the etching solution includes 40% ferric chloride, 0.5% hydrochloric acid, 0.5% sodium octane sulfonate and 59% water. Or, the etching solution includes 40% ferric chloride, 0.5% hydrochloric acid, 0.8% sodium octane sulfonate and 58.7% water. Or, the etching solution includes 40% ferric chloride, 0.8% hydrochloric acid, 0.5% sodium octane sulfonate and 58.7% water. Or, the etching solution includes 40% ferric chloride, 1% hydrochloric acid, 1% sodium octane sulfonate and 58% water. Or, the etching solution includes 40% ferric chloride, 1% hydrochloric acid, 2% sodium octane sulfonate and 57% water. Or, the etching solution includes 45% ferric chloride, 0.5% hydrochloric acid, 1% sodium octane sulfonate and 53.5% water. Or, the etching solution includes 45% ferric chloride, 1% hydrochloric acid, 0.5% sodium octane sulfonate and 53.5% water. Or, the etching solution includes 45% ferric chloride, 1% hydrochloric acid, 1.5% sodium octane sulfonate and 52.5% water. Or, the etching solution includes 45% ferric chloride, 1% hydrochloric acid, 2% sodium octane sulfonate and 52% water. Or, the etching solution includes 50% ferric chloride, 0.5% hydrochloric acid, 1% sodium octane sulfonate and 48.5% water. Or, the etching solution includes 50% ferric chloride, 0.5% hydrochloric acid, 1.5% sodium octane sulfonate and 48% water. Or, the etching solution includes 50% ferric chloride, 1% hydrochloric acid, 1.5% sodium octane sulfonate and 47.5% water. Or, the etching solution includes 50% ferric chloride, 1% hydrochloric acid, 2% sodium octane sulfonate and 47% water.

[0037] Among them, the proportion of sodium octane sulfonate is between 0.5% and 1.5%. The proportion of sodium octane sulfonate can be set to 0.5%, or, the proportion of sodium octane sulfonate can be set to 0.8%, or, the proportion of sodium octane sulfonate can be set to 1%, or, the proportion of sodium octane sulfonate can be set to 1.2%, or, the proportion of sodium octane sulfonate can be set to 1.5%.

[0038] It should be noted that during the etching process, the ratio of the etching solution to the liquid in the etching tank is between 0.5% and 2%. After the concentration of the solution in the etching tank drops to the set value, the staff will add the etching solution into the etching tank to increase the concentration of the etching solution in the etching tank.

[0039] Among them, the proportion of hydrochloric acid can be set to 0.5%.

[0040] Among them, the surface tension of the etching solution is between 20 - 25 mN / m. For example, the surface tension of the etching solution can be set to 20 mN / m, or, the surface tension of the etching solution can be set to 22 mN / m, or, the surface tension of the etching solution can be set to 24 mN / m, or, the surface tension of the etching solution can be set to 25 mN / m.

[0041] In addition, when the etching solution comprises 45% ferric chloride, 0.5% hydrochloric acid, 1% sodium octane sulfonate and 53.5% water, the surface tension of the etching solution is 23.1 mN / m, and the uniformity of the openings of the etching evaporation source on the mask substrate is 0.9 (3σ criterion, the smaller the value, the better).

[0042] In addition, when the etching solution comprises 45% ferric chloride, 0.5% hydrochloric acid, 1.25% sodium octane sulfonate and 53.25% water, the surface tension of the etching solution is 22.6 mN / m, and the uniformity of the openings of the etching evaporation source on the mask substrate is 0.9 (3σ criterion, the smaller the value, the better).

[0043] When using the production process of the prior art, the uniformity of the openings of the etching evaporation source on the mask substrate is 5 (3σ criterion, the smaller the value, the better).

[0044] It should be noted that the foaming height of the etching solution with sodium octane sulfonate can be reduced, so that the foaming height of the etching solution is reduced to 2 - 4 mm, and the bubble elimination time can be shortened to within 2 minutes, and there is no abnormal reaction, and no impurities will remain on the mask substrate.

[0045] As shown in Table 1 below, in the comparative examples of the production process of the prior art and the production method of the OLED metal mask opening morphology provided in this embodiment, the reference conditions are as follows:

[0046] 1. Base condition: etching solution of the prior art, surface tension 42 mN / m; wetting agent condition: production solution of this embodiment, using 1% sodium octane sulfonate, surface tension 23 mN / m;

[0047] 2. Select a mask pattern with an opening of 25 um * 25 um, and the CD after etching

[0048] The opening size is 35 um * 35 um;

[0049] 3. Explanation of the missing corner rate statistics: For each condition, there are 5 regions (Cells) in a single sample, and there are 9 grid points in each Cell, totaling 135 points; there are 9 patterns in each picture, and if there is a missing corner in one pattern, it is considered a missing corner at this point. The missing corner rate is calculated by dividing the number of missing corners at the points by the total number of points.

[0050] The test results are shown in Table 1.

[0051] Table 1

[0052]

[0053] As shown in Table 1, the production method of the OLED metal mask opening morphology provided in this embodiment can reduce the average missing corner rate from 76% to 20%, can significantly reduce the missing corners of the mask, and improve the production quality and yield of the subsequent OLED screen evaporation process.

[0054] See Figure 1 and Figure 2 As shown, the method for producing the opening topography of the OLED metal mask plate provided in this embodiment can effectively reduce the rounded corners at the four corners of the openings on the metal mask plate and reduce the corner missing phenomenon. However, for the metal mask plate produced by the prior art, the rounded corners at the four corners of the openings are relatively large, and the corner missing phenomenon is obvious.

[0055] It should be noted that the main function of the metal mask plate is to deposit RGB organic substances passing through the mask and form pixels during the OLED production process, and deposit organic substances accurately and finely where needed. The denser the small holes on the metal mask plate, the smaller the generated pixel points, and the higher the resolution of the OLED screen. Generally, tens of millions of small holes need to be opened on a single metal mask plate, and each small hole corresponds to a pixel point of the OLED screen. Therefore, the opening topography of each small hole determines the quality of the OLED pixel points. The acute angles at the four corners of the openings of the small holes in the prior art cannot be completely opened, resulting in, as Figure 2 shown, the acute angles around the openings of the small holes are rounded corners. This will cause defects in the pixel points of the OLED screen during the later evaporation process, with a low pass rate, resulting in poor quality of the OLED screen and easy screen burning. However, for the metal mask plate produced by the method for producing the opening topography of the OLED metal mask plate provided in this embodiment, the opening topography of the small holes on it is complete, the acute angles around are clear, the pass rate is high, and the quality and pass rate of the later production of the OLED screen will also be improved, reducing the production cost.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A production method for the opening morphology of an OLED metal mask plate, characterized in that, It includes the following steps: Load the mask plate substrate, wash the mask plate substrate with RO pure water, and perform pickling on the washed mask plate substrate; Etch the mask plate substrate with an etching solution, where the etching solution includes 40%-50% ferric chloride, 0.5%-1% hydrochloric acid, 0.5%-2% sodium octane sulfonate, and 47%-59% water; Perform alkali washing on the etched mask plate substrate, and perform water washing after alkali washing; Dry the mask plate substrate and unload it; The surface tension of the etching solution is between 20-25 mN / m.

2. The production method of the opening topography of the OLED metal mask plate according to claim 1, characterized in that The temperature of the etching solution is between 24°C-41°C.

3. The method for producing the opening topography of the OLED metal mask plate according to claim 1, characterized in that The specific gravity of the sodium octane sulfonate is between 0.5%-1.5%.

4. The method for producing the opening morphology of the OLED metal mask plate according to claim 3, wherein The specific gravity of the sodium octane sulfonate is between 0.8%-1.2%.

5. The method for producing the opening morphology of the OLED metal mask plate according to claim 4, characterized in that, The specific gravity of the sodium octane sulfonate is 1%.

6. The method for producing the opening topography of the OLED metal mask plate according to claim 1, wherein The specific gravity of the hydrochloric acid is 0.5%.

7. The production method of the opening topography of the OLED metal mask plate according to claim 1, characterized in that The surface tension of the etching solution is between 22-24 mN / m.

8. The method for producing the opening topography of the OLED metal mask plate according to claim 1, wherein The alkali washing solution uses an aqueous solution of 1% sodium hydroxide.

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