A photomask, a metal mask, and a manufacturing method

Abstract

The application relates to the technical field of display, and provides a photomask, a metal mask and a preparation method, which comprise a pattern definition region, the pattern definition region is used for defining a pixel opening region of the metal mask, the pattern definition region is a closed pattern composed of four inner concave arcs and a round corner connecting the inner concave arcs, the pixel opening region is a round-cornered rectangle, the center of the pattern definition region is coincident with the center of the pixel opening region, and the area of the pattern definition region is smaller than the area of the pixel opening region. The pattern of the pattern definition region transferred on the metal mask can make the liquid medicine more uniformly distributed on the whole surface, effectively reduce the formation of vortex and dead zones, avoid the liquid medicine to be retained in local areas, thereby reducing the problems of impurity accumulation and incomplete reaction, reducing the etching inconsistency caused by uneven flow, and improving the etching uniformity of the round corners and the etching uniformity of the straight edges of the pixel opening region of the metal mask.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a photomask, a metal mask and a preparation method. BACKGROUND

[0002] In the field of display, FMM (Fine Metal Mask) is a key material for OLED (Organic Light Emitting Diode) panel manufacturing. It is mainly used in the vacuum evaporation process, and RGB (red, green, and blue) sub-pixel materials are evaporated to the display panel through the pixel opening area on the FMM, thereby realizing high-resolution display.

[0003] When manufacturing the FMM, the pixel opening area needs to be defined by the pattern on the photomask, and then etched by wet etching. For example, Figure 1 When the pixel opening area in the required FMM is a rounded rectangle, if the pattern on the photomask adopts a normal rectangle, the 90° right angle will cause the etching of the rounded corners of the pixel opening area to be out of place, so the existing pattern on the photomask is composed of four straight-line convex corner structures and four straight edges. Figure 1 However, this photomask pattern still limits the actual manufacturing space of the rounded corners of the pixel opening area, because the straight-line convex corner structure will cause the flow lines to change suddenly at the right angle or sharp corner or the intersection of two straight lines, easily forming vortex and dead zone, causing uneven flow, and the four rounded corners may have different radii, and the four straight edges may not be etched uniformly, resulting in that the uniformity of the rounded corners and straight edges of the pixel opening area of the FMM product cannot be effectively guaranteed.

[0004] Therefore, it is necessary to solve the problem of poor uniformity of the rounded corners and straight edges of the pixel opening area of the FMM product. SUMMARY

[0005] The purpose of the present application is to provide a photomask, a metal mask and a preparation method, to solve the technical problem of poor internal pattern uniformity of the pixel opening area of the FMM product in the prior art.

[0006] In a first aspect, an embodiment of the present application provides a photomask, comprising: a pattern definition area, the pattern definition area being used to define a pixel opening area of a metal mask, the pattern definition area being a first closed pattern composed of four concave arcs and rounded corners connecting the concave arcs, the pixel opening area being a first rounded rectangle, the first closed pattern being coincident with the center of the first rounded rectangle and the area of the first closed pattern being smaller than the area of the first rounded rectangle.

[0007] Further, a length of a short side of the pattern defining region is a first critical dimension, a distance between a midpoint of an arc of a round corner of the pattern defining region and a midpoint of an arc of a round corner of the pixel opening region is a first distance, when the first critical dimension is greater than or equal to 25 microns and less than or equal to 45 microns, the first distance is greater than or equal to one fifth of the first critical dimension and less than one half of the first critical dimension; when the first critical dimension is greater than 45 microns and less than or equal to 80 microns, the first distance is greater than or equal to one eighth of the first critical dimension and less than one third of the first critical dimension.

[0008] Further, when the first critical dimension is greater than or equal to 25 microns and less than or equal to 45 microns, the first distance is a first length; when the first critical dimension is greater than 45 microns and less than or equal to 80 microns, the first distance is a second length; the first length is greater than the second length.

[0009] Further, a round corner radius of the pattern defining region is a difference between a round corner radius of the pixel opening region and the first distance.

[0010] Further, an arc length of the round corner of the pattern defining region is one fourth of a circle.

[0011] Further, a distance between a midpoint of a line connecting a midpoint of the concave arc and end points of two adjacent round corners is a second distance, a length of a side of the pixel opening region corresponding to the concave arc is a second critical dimension, and the second distance increases logarithmically with the second critical dimension.

[0012] Further, when the second critical dimension is greater than or equal to 25 microns and less than or equal to 40 microns, the second distance is a first recess depth; when the second critical dimension is greater than or equal to 40 microns and less than or equal to 50 microns, the second distance is a second recess depth; when the second critical dimension is greater than or equal to 50 microns and less than or equal to 80 microns, the second distance is a third recess depth.

[0013] Further, the first recess depth is less than the second recess depth, and the second recess depth is less than the third recess depth.

[0014] In a second aspect, an embodiment of the present application further provides a metal mask plate prepared by using the photomask.

[0015] In a third aspect, an embodiment of the present application further provides a preparation method of a metal mask plate, the metal mask plate is prepared by using the photomask, and subsequent etching is performed by using a wet etching process.

[0016] The embodiment of the present application has at least the following technical effects:

[0017] The photomask provided by the embodiment of the present application is applied to an exposure machine to manufacture a metal mask plate. The photomask includes a plurality of densely arranged pattern definition regions. The pattern definition regions are used to define pixel opening regions of the metal mask plate. The pattern definition regions are regions that cannot transmit light. After exposure, the pattern definition regions are left on the metal mask plate. After wet etching, the pixel opening regions are etched by etching agents. Therefore, the centers of the pattern definition regions and the pixel opening regions coincide. The wet etching method is based on the non-directional corrosion of the etching agents. After wet etching, the pixel opening regions have larger opening areas than the pattern definition regions. Since the pixel opening regions of the metal mask plate to be manufactured are circular rectangles, the pattern of the pattern definition regions is a closed pattern composed of four concave arcs and a circular corner connecting the concave arcs. The circular corner connecting the concave arcs is a first circular corner.

[0018] In the process of wet etching, the closed pattern composed of the concave arcs and the first circular corner on the metal mask plate can make the etching agents more uniformly distributed on the entire surface, effectively reduce the formation of eddy currents and dead zones, avoid the stagnation of the etching agents in local regions, thereby reducing the problems of impurity accumulation and incomplete reaction, reducing the etching inconsistency caused by uneven flow, and improving the etching uniformity of the circular corners and the straight edges of the pixel opening regions. At the same time, by matching the concave arcs with the first circular corner, the present application increases the manufacturing space of the circular corners of the pixel opening regions and solves the space limitation problem caused by the convex corner structure in the prior art. By optimizing the structural design of the pattern definition regions, the manufacturing space and uniformity of the circular corners and the uniformity of the straight edges of the pixel opening regions are ensured, and the performance and yield of the metal mask plate are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The prior art schematic diagram provided by the present application;

[0021] Figure 2 The structural schematic diagram of the photomask provided by the embodiment of the present application;

[0022] Figure 3 The circular corner size relationship schematic diagram of the photomask provided by the embodiment of the present application;

[0023] Figure 4A schematic diagram of the concave arc recess relationship of a first structure of a photomask provided by the embodiment of the present application is shown in the figure.

[0024] Figure 5 A schematic diagram of the concave arc recess relationship of a second structure of a photomask provided by the embodiment of the present application is shown in the figure.

[0025] Icon: 1- graphic definition area; 2- pixel opening area; 11- concave arc; 12- first round corner; 21- second straight side; 22- second round corner. DETAILED DESCRIPTION

[0026] The technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0027] Those skilled in the art can understand that, unless otherwise defined, all the terms (including technical terms and scientific terms) used herein have the same meaning as that generally understood by those skilled in the art to which the present application belongs. It should also be understood that, those terms such as those defined in general dictionaries should be understood as having the same meaning as that in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as such.

[0028] Those skilled in the art can understand that, unless otherwise stated, the singular forms “a”, “an” and “the” used herein also include the plural forms. It should be further understood that the use of the phrase “comprising” in the specification of the present application means that the features, integers, steps, operations, elements and / or components exist, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof. The phrase “and / or” used herein includes all or any one of the associated listed items and all combinations thereof.

[0029] In a first aspect, referring to Figures 2 to 5 The embodiment of the present application provides a photomask, which comprises: a graphic definition area 1, the graphic definition area 1 is used for defining a pixel opening area 2 of a metal mask, the graphic definition area 1 is a closed graphic composed of four concave arcs 11 and round corners connecting the concave arcs 11, the pixel opening area 2 is a round-cornered rectangle, the center of the graphic definition area 1 coincides with that of the pixel opening area 2, and the area of the graphic definition area 1 is smaller than that of the pixel opening area 2.

[0030] In this embodiment, the photomask is applied to an exposure machine for manufacturing a metal mask, the photomask includes a plurality of densely arranged pattern definition regions 1, the pattern definition region 1 is used to define a pixel opening region 2 of the metal mask, the pattern definition region 1 can be understood as a region that light cannot penetrate, after exposure, the pattern of the pattern definition region 1 is left on the metal mask, and then after wet etching, the pixel opening region 2 is etched by the etching agent, so the center of the pattern definition region 1 and the pixel opening region 2 coincide, and the wet etching method is due to the non-directional corrosion of the liquid medicine, so after wet etching, the pixel opening region 2 with a larger opening area than the area of the pattern definition region 1 is obtained. Since it is desired to prepare a pixel opening region 2 of the metal mask as a rounded rectangle, the pattern of the pattern definition region 1 is a closed pattern composed of four concave arcs 11 and rounded corners connecting the concave arcs 11, and the rounded corner connecting the concave arcs 11 is a first rounded corner 12.

[0031] In the process of wet etching, the closed pattern composed of the concave arcs 11 and the first rounded corner 12 transferred on the metal mask can make the liquid medicine more uniformly distributed on the entire surface, effectively reduce the formation of eddy current and dead zone, avoid the liquid medicine to stay in the local area, thereby reducing the problem of impurity accumulation and incomplete reaction, reducing the etching inconsistency caused by uneven flow, thereby improving the etching uniformity of the rounded corners and the straight edges of the pixel opening region 2. At the same time, by matching the concave arcs 11 with the first rounded corner 12, the present scheme increases the manufacturing space of the rounded corners of the pixel opening region 2, and also solves the space limitation problem caused by the convex corner structure in the prior art. By optimizing the structural design of the pattern definition region 1, the manufacturing space and uniformity of the rounded corners and the uniformity of the straight edges of the pixel opening region 2 are ensured, and the performance and yield of the metal mask are significantly improved.

[0032] Optionally, please refer to Figure 3 The length of the short side of the pixel opening region 2 is the first critical dimension D1, the distance between the arc midpoint of the rounded corner of the pattern definition region 1 and the arc midpoint of the rounded corner of the pixel opening region 2 is the first distance X1, when the first critical dimension D1 is greater than or equal to 25 microns and less than or equal to 45 microns, the first distance X1 is greater than or equal to one fifth of the first critical dimension D1 and less than one half of the first critical dimension D1; when the first critical dimension D1 is greater than 45 microns and less than or equal to 80 microns, the first distance X1 is greater than or equal to one eighth of the first critical dimension D1 and less than one third of the first critical dimension D1.

[0033] In this embodiment, the length of the short side of the pixel opening region 2 is the first critical dimension D1, it should be noted that the short side here does not mean that the pixel opening region 2 is only the short side of the rounded rectangular, for example Figure 3The pixel opening area 2 in the above embodiment is a circular rectangle. In this case, the first critical dimension D1 is the length of the short side of the circular rectangle. Figure 2 The pixel opening area 2 in the above embodiment is a circular rectangle. In this case, the first critical dimension D1 is the length of the short side of the circular rectangle. The first distance X1 is defined as the distance between the arc midpoints of the first rounded corner 12 and the corresponding second rounded corner 22. If the first critical dimension D1 of the pixel opening area 2 on the target mask is between 25-80 microns, the first distance X1 should follow the following rules: when 25μm≤D1≤45μm, D1≤X1≤ D1; when 45μm<D1≤80μm, D1≤X1≤ D1. For example, when the first critical dimension D1 is 45μm, the first distance X1 is selected between 9μm-22.5μm, and the arc midpoints of the four rounded corners of the pattern defining area 1 on the mask can be determined accordingly. When the first distance X1 follows the above rules, the desired transfer pattern on the mask can be prepared according to the pattern defining area 1 on the mask, and then the size of the pixel opening area 2 on the target mask can be etched.

[0034] Alternatively, when the first critical dimension D1 is greater than or equal to 25 microns and less than or equal to 45 microns, the first distance X1 is a first length; when the first critical dimension D1 is greater than 45 microns and less than or equal to 80 microns, the first distance X1 is a second length; the first length is greater than the second length.

[0035] In the above embodiment, when the value range of X1 is followed, the first distance X1 can be selected according to the following value mode: when 25μm≤D1≤45μm, the first distance X1 can be the same length, and the value range of the first distance X1 should be the intersection of the value ranges of the first critical dimension D1 at 25μm and 45μm; when 45μm<D1≤80μm, the first distance X1 can be the same length, and the value range of the first distance X1 should be the intersection of the value ranges of the first critical dimension D1 at greater than 45μm and 80μm. The advantage of taking the same length is that it can reduce the variable links, increase the reliability of the design, unify the rules of consensus in production, and increase the quality stability of the product. Preferably, the first length should be greater than the second length, and the size of the first distance when 25μm≤D1≤45μm is smaller than the size of the first distance when 45μm<D1≤80μm, so as to ensure better etching effect.

[0036] Optionally, the radius of the rounded corner of the graphic definition area 1 is the difference between the radius of the rounded corner of the pixel opening area 2 and the first distance X1. In the embodiment, the radius of the first rounded corner 12 is the difference between the radius of the rounded corner of the pixel opening area 2 and the first distance X1, and the rounded corners of the first rounded corner 12 and the pixel opening area 2 have the same center, which is under the action of the wet etching solution, in order to ensure that the etching is uniform like the second rounded corner 22.

[0037] Optionally, the arc length of the rounded corner of the graphic definition area 1 is one fourth of the circle. In the embodiment, the arc length of the first rounded corner 12 is one fourth of the circle with the radius of the difference between the radius of the rounded corner of the second rounded corner 22 and the first distance X1, which not only ensures that the etching of the rounded corner of the pixel opening area 2 is uniform, but also ensures that the flow of the solution between the first rounded corner 12 and the inner recessed arc 11 is more uniform, and the straight side of the pixel opening area 2 is the second straight side 21, which also ensures that the second straight side 21 can be etched uniformly by the solution.

[0038] Optionally, the distance between the midpoint of the inner recessed arc 11 and the midpoint of the line connecting the endpoints of the adjacent two first rounded corners 12 is the second distance, so each inner recessed arc 11 has its corresponding recessed depth, that is, the second distance, and the second critical dimension is the length corresponding to the side of the pixel opening area 2. As shown in FIG. 6, if the pixel opening area 2 is a rounded rectangle, then the recessed depth of the inner recessed arc 11, that is, the second distance, includes X21 and X22, and the corresponding second critical dimensions are D21 and D22, respectively. Figure 4 As shown in FIG. 7, if the pixel opening area 2 is a rounded square, then the recessed depth of the inner recessed arc 11 is the same, that is, the second distance X2 is the same, and the second critical dimension D2 is also the same. Figure 5

[0039] Optionally, the second distance X2 increases logarithmically with the second critical dimension D2. In the embodiment, the recessed depth of the inner recessed arc 11 and the length corresponding to the side of the pixel opening area present a logarithmic growth trend, whether the pixel opening area 2 is a rounded rectangle, the second distances X21 and X22 follow the logarithmic growth trend with the second critical dimensions D21 and D22, respectively, or the pixel opening area 2 is a rounded square, the second distance X2 follows the logarithmic growth rule with the second critical dimension D2. Specifically, taking the second critical dimension as the independent variable x and the second distance as the dependent variable y, the growth relationship between the second critical dimension and the second distance is: y = a * ln(x) - b, wherein 0.55 ≤ a ≤ 0.65 and 1.4 ≤ b ≤ 1.6, which ensures that each straight side of the pixel opening area 2 can also be etched uniformly.

[0040] ​Optionally, when the second critical dimension is greater than or equal to 25 microns and less than 40 microns, the second distance is the first recess depth; when the second critical dimension is greater than or equal to 40 microns and less than or equal to 50 microns, the second distance is the second recess depth; and when the second critical dimension is greater than 50 microns and less than or equal to 80 microns, the second distance is the third recess depth.

[0041] In the embodiment, taking the pixel opening area 2 as a circular square as an example, if the second critical dimension 25 μm≤D2<40 μm, the second distance X2 is the first recess depth, that is, the recess of the inner recess arc 11, that is, the second distance X2, can be the same value when the second critical dimension D2 is 25 μm and when the second critical dimension D2 is 39 μm, and at this time, the value range of the first distance X2 should be the intersection of the value range of the second critical dimension D2 when the second critical dimension D2 is 25 μm and less than 40 μm. If the second critical dimension 40 μm≤D2≤50 μm, the second distance X2 is the second recess depth, for example, the recess of the inner recess arc 11, that is, the second distance X2, can be the same value when the second critical dimension D2 is 40 μm and when the second critical dimension D2 is 50 μm, and at this time, the value range of the first distance X2 should be the intersection of the value range of the second critical dimension D2 when the second critical dimension D2 is 40 μm and 50 μm. If the second critical dimension 50 μm<D2≤80 μm, the second distance X2 is the third recess depth, for example, the recess of the inner recess arc 11, that is, the second distance X2, can be the same value when the second critical dimension D2 is 51 μm and when the second critical dimension D2 is 50 μm, and at this time, the value range of the first distance X2 should be the intersection of the value range of the second critical dimension D2 when the second critical dimension D2 is greater than 50 μm and 80 μm.

[0042] Optionally, the first recess depth is less than the second recess depth, which is less than the third recess depth. In the embodiment, because the recess of the inner recess arc can be larger when the second critical dimension D2 is larger, the first recess depth is less than the second recess depth, which is less than the third recess depth when the value is taken, so as to ensure better etching effect.

[0043] In a second aspect, the embodiment of the present application provides a metal mask plate prepared by using the mask as described above. The mask as described above is used on an exposure machine to transfer a corresponding pattern on the metal mask plate, so as to obtain a corresponding pixel opening area.

[0044] Optionally, the material of the metal mask plate includes Invar. In the embodiment, because the material of the metal mask plate is Invar, the mask in the first aspect needs to be used to prepare the corresponding pixel opening area according to the design rules of the graphic definition area.

[0045] The metal mask plate in the embodiment is prepared by using the photomask in the first aspect. Details not described in the embodiment can be found in the specific description of the first aspect and Figures 2 to 5

[0046] In the third aspect, the embodiment of the present application provides a preparation method of a metal mask plate. The metal mask plate is prepared by using the photomask described above, and then etched by using a wet etching process. After the metal mask plate is exposed by using the photomask in the first aspect, the wet etching process is used for etching, so that a desired pixel opening area is obtained. Here, the wet etching can be directly performed after exposure, or a process that does not change the pattern composed of the concave arc and the first fillet transferred on the metal mask plate can be added between exposure and wet etching, for example, cleaning, which does not react with the photoresist and the metal mask plate itself.

[0047] The preparation method of the metal mask plate in the embodiment is prepared by using the photomask in the first aspect. Details not described in the embodiment can be found in the specific description of the first aspect and Figures 2 to 5

[0048] Those skilled in the art can understand that the steps, measures and schemes in various operations, methods and processes discussed in the present application can be alternated, changed, combined or deleted. Further, other steps, measures and schemes in various operations, methods and processes discussed in the present application can also be alternated, changed, rearranged, decomposed, combined or deleted. Further, the steps, measures and schemes in the prior art with the various operations, methods and processes disclosed in the present application can also be alternated, changed, rearranged, decomposed, combined or deleted.

[0049] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0050] The terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise stated, the meaning of "multiple" is two or more.

[0051] ​​In the description of the application, it should be noted that unless otherwise expressly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium; can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood in specific circumstances.

[0052] In the description of the present application, the specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0053] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part 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 application.

Claims

1. A reticle, characterized by, The application relates to a photomask and a method for manufacturing a metal mask plate. The graphic definition region is a closed graphic composed of four concave arcs and rounded corners connecting the concave arcs, and the pixel opening region is a rounded rectangle, the center of the graphic definition region coincides with the center of the pixel opening region, and the area of the graphic definition region is smaller than the area of the pixel opening region.

2. The photomask of claim 1, wherein, The length of the short side of the graphic definition region is a first critical dimension, the distance between the arc midpoint of the rounded corner of the graphic definition region and the arc midpoint of the rounded corner of the pixel opening region is a first distance, when the first critical dimension is greater than or equal to 25 microns and smaller than or equal to 45 microns, the first distance is greater than or equal to one fifth of the first critical dimension and smaller than one half of the first critical dimension; when the first critical dimension is greater than 45 microns and smaller than or equal to 80 microns, the first distance is greater than or equal to one eighth of the first critical dimension and smaller than one third of the first critical dimension.

3. The photomask of claim 2, wherein, When the first critical dimension is greater than or equal to 25 microns and smaller than or equal to 45 microns, the first distance is a first length; when the first critical dimension is greater than 45 microns and smaller than or equal to 80 microns, the first distance is a second length; the first length is greater than the second length.

4. The photomask of claim 2, wherein, The rounded corner radius of the graphic definition region is the difference between the rounded corner radius of the pixel opening region and the first distance.

5. The photomask of claim 4, wherein, The arc length of the rounded corner of the graphic definition region is one fourth of a circle.

6. The photomask of claim 2, wherein, The distance between the midpoint of the line connecting the arc midpoints of the concave arcs and the end points of the adjacent two rounded corners is a second distance, the length of the side of the pixel opening region corresponding to the concave arc is a second critical dimension, and the second distance logarithmically increases with the second critical dimension.

7. The photomask of claim 6, wherein, When the second critical dimension is greater than or equal to 25 microns and smaller than or equal to 40 microns, the second distance is a first recess depth; When the second critical dimension is greater than or equal to 40 microns and smaller than or equal to 50 microns, the second distance is a second recess depth; When the second critical dimension is greater than or equal to 50 microns and smaller than or equal to 80 microns, the second distance is a third recess depth.

8. The photomask of claim 7, wherein, The first recess depth is smaller than the second recess depth, and the second recess depth is smaller than the third recess depth.

9. A metal mask, characterized by The photomask is prepared according to any one of claims 1-8.

10. A method for producing a metal mask, characterized by, The metal mask plate is prepared according to any one of claims 1-8, and then etched by a wet etching process.

Images