OLED metal mask plate opening morphology production method

Abstract

The invention provides an OLED metal mask plate opening morphology production method, and relates to the technical field of mask plate production. The OLED metal mask plate opening morphology production method comprises the following steps: feeding a mask plate substrate, cleaning the mask plate substrate with RO pure water, and carrying out acid pickling on the cleaned mask plate substrate; etching the mask substrate by using an etching solution, wherein the etching solution comprises 40%-50% of ferric chloride, 0.5%-1% of hydrochloric acid, 0.5%-2% of sodium n-octane sulfonate and 47%-59% of water; performing alkali washing on the etched mask substrate, and performing water washing after alkali washing; and drying and blanking the mask substrate. The technical effect that the required pattern size on the fine metal mask reaches the standard is achieved.

Description

Technical Field

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

[0002] Many film structures in organic light-emitting diodes (OLEDs) are formed by evaporation using a metal mask assembly (MFA). A complete set of metal mask assemblies (MFA) usually consists of a mask frame (Frame), a fine metal mask (FMM), 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 structure.

[0003] At present, fine metal mask plates are produced by wet etching process. The areas on the fine metal mask plates that are not protected by dry film react with the etching substrate through the liquid medicine to obtain the required pattern. However, in the etching process of fine metal mask plates under the existing technical scheme, the sharp-angle pattern is prone to chipping after etching, resulting in poor uniformity of the size (CD) of the etched desired pattern (large and small hole phenomenon) and the CD of the holes in abnormal areas is small, resulting in the client's evaporation size not meeting the set size during the evaporation process, which will seriously cause dark spot problems and affect product quality. Summary of the invention

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

[0005] In a first aspect, an embodiment of the present invention provides a method for producing an opening morphology of an OLED metal mask, comprising the following steps: The mask plate substrate is loaded, the mask plate substrate is cleaned with RO pure water, and the cleaned mask plate substrate is pickled; The mask substrate is etched using an etching solution, wherein the etching solution includes 40%-50% ferric chloride, 0.5%-1% hydrochloric acid, 0.5%-2% sodium n-octane sulfonate and 47%-59% water; Performing alkali washing on the etched mask substrate, and then washing with water; Dry the mask substrate and unload the material.

[0006] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the temperature of the etching solution is between 24° C. and 41° C.

[0007] In combination with the first aspect, the embodiment of the present invention provides a possible implementation of the first aspect, wherein the specific gravity of the above-mentioned sodium n-octane sulfonate is between 0.5% and 1.5%.

[0008] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the specific gravity of the above-mentioned sodium n-octane sulfonate is between 0.8% and 1.2%.

[0009] In combination with the first aspect, the embodiment of the present invention provides a possible implementation of the first aspect, wherein the specific gravity of the above-mentioned sodium n-octane sulfonate is 1%.

[0010] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the specific gravity of the hydrochloric acid is 0.5%.

[0011] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the surface tension of the etching solution is between 20-25 mN / m.

[0012] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the surface tension of the etching solution is between 22-24 mN / m.

[0013] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the alkaline washing solution is a 1% sodium hydroxide aqueous solution.

[0014] Beneficial effects: The invention provides a method for producing an opening morphology of an OLED metal mask plate, comprising the following steps: loading a mask plate substrate, cleaning the mask plate substrate with RO pure water, and 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 n-octane sulfonate and 47%-59% water; alkali-washing the etched mask plate substrate, and then washing with water; drying the mask plate substrate and unloading the material.

[0015] Specifically, the fine metal mask plate is used to produce OLED screens. In 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 on the mask plate substrate, and then the mask plate substrate is pickled after cleaning to neutralize the residual alkali solution in the previous stage by pickling, and then it is washed with water to remove the residual liquid and impurities, and then the mask plate substrate is etched by an etching solution containing ferric chloride, hydrochloric acid and sodium n-octane sulfonate to etch the evaporation source opening on the mask plate substrate, and the mask plate substrate is alkaline washed after etching, and then dried and unloaded, wherein sodium n-octane sulfonate is added to the etching solution, so that the etching solution can better enter every corner of the pre-etched area, especially the sharp angle area of ​​the pre-etched area, so that the etching solution can etch comprehensively, ensuring that the size of the evaporation source opening after etching is uniform, thereby ensuring the production quality of OLED. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of a local opening of a metal mask produced by the method for producing an opening morphology of an OLED metal mask provided by an embodiment of the present invention; Figure 2 A schematic diagram of a partial opening of a metal mask produced using prior art. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] The present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0023] See also Figure 1 and Figure 2 As shown, this embodiment provides a method for producing an opening morphology of an OLED metal mask plate, comprising the following steps: loading a mask plate substrate, cleaning the mask plate substrate with RO pure water, and pickling the cleaned mask plate substrate; etching the mask plate substrate with an etching solution, the etching solution comprising ferric chloride, hydrochloric acid and sodium n-octane sulfonate; alkaline washing the etched mask plate substrate, and then washing with water; drying the mask plate substrate and unloading.

[0024] Specifically, the fine metal mask plate is used to produce OLED screens. In 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 on the mask plate substrate, and then the mask plate substrate is pickled after cleaning to neutralize the residual alkali solution in the previous stage by pickling, and then it is washed with water to remove the residual liquid and impurities, and then the mask plate substrate is etched by an etching solution containing ferric chloride, hydrochloric acid and sodium n-octane sulfonate to etch the evaporation source opening on the mask plate substrate, and the mask plate substrate is alkaline washed after etching, and then dried and unloaded, wherein sodium n-octane sulfonate is added to the etching solution, so that the etching solution can better enter every corner of the pre-etched area, especially the sharp angle area of ​​the pre-etched area, so that the etching solution can etch comprehensively, ensuring that the size of the evaporation source opening after etching is uniform, thereby ensuring the production quality of OLED.

[0025] Among them, RO pure water is water filtered through a reverse osmosis membrane and has a high degree of purity.

[0026] Among them, in the existing production process, due to the surface tension of the wet etching solution, the etching solution cannot evenly enter every corner of the etching area, especially in the sharp-angle area, the solution replacement is slower than that in the normal area. Therefore, the size of each evaporation source opening cannot be guaranteed to be exactly the same, and etching corners appear. As a result, the size (CD) of the etched desired pattern (evaporation source opening) is not uniform (large and small holes) and the CD of the evaporation source opening in the abnormal area is small. In the subsequent customer-end evaporation process, the evaporation size does not meet the set size, which will seriously cause dark spot problems and reduce product quality.

[0027] 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.

[0028] Wherein, the alkaline washing solution adopts 1% sodium hydroxide aqueous solution.

[0029] In an optional solution of this embodiment, the etching solution includes 40%-50% ferric chloride, 0.5%-1% hydrochloric acid, 0.5%-2% sodium n-octane sulfonate and 47%-59% water.

[0030] Specifically, the etching solution includes 40% ferric chloride, 0.5% hydrochloric acid, 0.5% sodium n-octane sulfonate and 59% water, or the etching solution includes 40% ferric chloride, 0.5% hydrochloric acid, 0.8% sodium n-octane sulfonate and 58.7% water, or the etching solution includes 40% ferric chloride, 0.8% hydrochloric acid, 0.5% sodium n-octane sulfonate and 58.7% water, or the etching solution includes 40% ferric chloride, 1% hydrochloric acid, 1% sodium n-octane sulfonate and 58% water, or the etching solution includes 40% ferric chloride, 1% hydrochloric acid, 2% sodium n-octane sulfonate and 57% water, or the etching solution includes 45% ferric chloride, 0.5% hydrochloric acid, 1% sodium n-octane sulfonate and 53.5% water, or the etching solution includes 45% ferric chloride, 1 % hydrochloric acid, 0.5% sodium n-octane sulfonate and 53.5% water, or the etching solution includes 45% ferric chloride, 1% hydrochloric acid, 1.5% sodium n-octane sulfonate and 52.5% water, or the etching solution includes 45% ferric chloride, 1% hydrochloric acid, 2% sodium n-octane sulfonate and 52% water, or the etching solution includes 50% ferric chloride, 0.5% hydrochloric acid, 1% sodium n-octane sulfonate and 48.5% water, or the etching solution includes 50% ferric chloride, 0.5% hydrochloric acid, 1.5% sodium n-octane sulfonate and 48% water, or the etching solution includes 50% ferric chloride, 1% hydrochloric acid, 1.5% sodium n-octane sulfonate and 47.5% water, or the etching solution includes 50% ferric chloride, 1% hydrochloric acid, 2% sodium n-octane sulfonate and 47% water.

[0031] The specific gravity of sodium n-octane sulfonate is between 0.5% and 1.5%. The specific gravity of sodium n-octane sulfonate can be set to 0.5%, or the specific gravity of sodium n-octane sulfonate can be set to 0.8%, or the specific gravity of sodium n-octane sulfonate can be set to 1%, or the specific gravity of sodium n-octane sulfonate can be set to 1.2%, or the specific gravity of sodium n-octane sulfonate can be set to 1.5%.

[0032] It should be pointed out that during the etching process, the ratio of etching liquid to liquid in the etching pool is between 0.5% and 2%. After the solubility of the solution in the etching pool is reduced to the set value, the staff will add etching liquid into the etching pool to increase the solubility of the etching liquid in the etching pool.

[0033] Among them, the specific gravity of hydrochloric acid can be set to 0.5%.

[0034] The surface tension of the etching solution is between 20 and 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.

[0035] In addition, when the etching solution includes 45% ferric chloride, 0.5% hydrochloric acid, 1% sodium n-octane sulfonate and 53.5% water, the surface tension of the etching solution is 23.1mN / m, and the uniformity of the etching evaporation source openings on the mask substrate is 0.9 (3σ criterion, the smaller the value, the better).

[0036] In addition, when the etching solution includes 45% ferric chloride, 0.5% hydrochloric acid, 1.25% sodium n-octane sulfonate and 53.25% water, the surface tension of the etching solution is 22.6mN / m, and the uniformity of the etching evaporation source openings on the mask substrate is 0.9 (3σ criterion, the smaller the value, the better).

[0037] When the existing production process is used, the uniformity of the etching evaporation source openings on the mask substrate is 5 (3σ criterion, the smaller the value, the better).

[0038] It should be pointed out that the bubble height of the etching solution containing sodium n-octane sulfonate can be reduced to 2-4 mm, and the bubble elimination time can be shortened to less than 2 minutes, without abnormal reaction and without residual impurities on the mask substrate.

[0039] As shown in Table 1 below, in the comparative example of the production process of the prior art and the method for producing the opening morphology of the OLED metal mask provided in this embodiment, the reference conditions are: 1. Base conditions: the existing etching solution, surface tension 42mN / m; wetting agent conditions: the production solution of this embodiment, using 1% sodium n-octane sulfonate, surface tension 23mN / m; 2. Select a mask pattern with an opening of 25um*25um, and CD after etching The opening size is 35um*35um; 3. Statistical explanation of missing corner rate: Each conditional single sample has 5 areas (Cell), each Cell has 9 grid points, totaling 135 points; each screen has 9 graphics, and if there is a missing corner, it is considered a missing corner of that point. The missing corner rate is the number of missing corners of points divided by the total number of points.

[0040] The test results are shown in Table 1.

[0041] Table 1

[0042] As shown in Table 1, the OLED metal mask opening morphology production method provided in this embodiment can reduce the average corner defect rate from 76% to 20%, which can significantly reduce the corner defect of the mask plate and improve the production quality and yield rate of the subsequent OLED screen evaporation process.

[0043] See also Figure 1 and Figure 2As shown, the method for producing the opening morphology of the OLED metal mask provided by this embodiment can effectively reduce the roundness of the four corners of the opening on the metal mask, thereby reducing the corner missing phenomenon. However, the four corners of the opening on the metal mask produced by the prior art have larger roundness and obvious corner missing phenomenon.

[0044] It should be pointed out that the main function of the metal mask is to deposit the RGB organic substances that pass through the mask and form pixels during the OLED production process. The organic substances are accurately and finely deposited where needed. The denser the holes on the metal mask, the smaller the generated pixels, and the higher the resolution of the OLED screen. Generally, tens of millions of holes need to be opened on a metal mask, and each hole corresponds to a pixel on the OLED screen. Therefore, the opening shape of each hole determines the quality of the OLED pixel. The sharp angles of the four corners of the opening of the hole in the prior art cannot be fully opened, resulting in Figure 2 As shown in the figure, the sharp angles around the small hole opening are rounded, which will cause defects in the pixels of the OLED screen during the later evaporation process, and the qualified rate is low, resulting in poor quality of the OLED screen and easy screen burn-in. However, the metal mask plate produced by the OLED metal mask plate opening morphology production method provided by this embodiment has a complete opening morphology of the small holes on it, clear sharp angles around it, and a high qualified rate. The quality and qualified rate of the OLED screen produced later will also be improved, reducing the production cost.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing an opening morphology of an OLED metal mask, characterized in that: The following steps are involved: The mask plate substrate is loaded, the mask plate substrate is cleaned with RO pure water, and the cleaned mask plate substrate is pickled; The mask substrate is etched using an etching solution, wherein the etching solution includes 40%-50% ferric chloride, 0.5%-1% hydrochloric acid, 0.5%-2% sodium n-octane sulfonate and 47%-59% water; Performing alkali washing on the etched mask substrate, and then washing with water; Dry the mask substrate and unload the material.

2. The method for producing the opening morphology of an OLED metal mask according to claim 1, characterized in that: The temperature of the etching solution is between 24°C and 41°C.

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

4. The method for producing the opening morphology of an OLED metal mask according to claim 3, characterized in that: The specific gravity of the sodium n-octane sulfonate is between 0.8% and 1.2%.

5. The method for producing the opening morphology of an OLED metal mask according to claim 4, characterized in that: The proportion of the sodium n-octane sulfonate is 1%.

6. The method for producing an opening profile of an OLED metal mask according to claim 1, characterized in that: The specific gravity of the hydrochloric acid is 0.5%.

7. The method for producing an opening profile of an OLED metal mask according to claim 1, characterized in that: The surface tension of the etching solution is between 20-25 mN / m.

8. The method for producing the opening morphology of an OLED metal mask according to claim 7, characterized in that: The surface tension of the etching solution is between 22-24 mN / m.

9. The method for producing an opening profile of an OLED metal mask according to claim 1, characterized in that: The alkaline washing solution is a 1% sodium hydroxide aqueous solution.

Images