A support mask and a mask device

Abstract

The application provides a support mask plate and a mask device, and relates to the technical field of semiconductor display. The support mask plate comprises a metal base body, the metal base body is provided with a plurality of first support strips and a plurality of second support strips, the first support strips and the second support strips are perpendicular to each other to form a mesh surface, and the mesh surface has at least one opening; the first support strips and / or the second support strips are provided with shielding parts, the shielding parts extend towards the inner side of the corresponding opening; the support mask plate further comprises an additional layer, the part of the first support strips and the second support strips surrounding the opening forms a solid area, the additional layer is arranged in the solid area, and a predetermined distance is arranged between the additional layer and the inner edge of the opening adjacent to the additional layer; the additional layer has a greater magnetic permeability than the metal base body. The mask device is provided with the above support mask plate. The application solves the problems of poor mask adhesion and product color mixing defects caused by the design of the mask plate during the production of the special-shaped screen in the prior art.

Description

Technical Field

[0001] This invention relates to the field of semiconductor display technology, and in particular to a support mask and a masking device. Background Technology

[0002] With the continuous development of the OLED screen market, various irregular screen shapes such as "waterdrop screen", "notch screen" and "blind hole screen" have gradually occupied the consumer market and become the mainstream design favored by the public.

[0003] For these irregularly shaped screens, the traditional processing method involves setting masking portions corresponding to the "waterdrop," "notch," or "blind hole" locations on the irregularly shaped screen within the patterned area of ​​a fine mask (FMM). These masking portions act as barriers during the vapor deposition process, preventing organic materials from being deposited onto the substrate and resulting in an irregularly shaped organic material film layer formed on the substrate. However, this traditional processing method suffers from poor adhesion between the masking portions on the fine mask and the substrate, easily leading to color mixing defects in the vapor-deposited products.

[0004] Therefore, a new design solution is urgently needed to solve the above problems. Summary of the Invention

[0005] To address the issues of poor mask bonding and color mixing in the production of irregularly shaped screens, this invention provides a supporting mask, which includes:

[0006] A metal substrate, comprising a plurality of first support strips and a plurality of second support strips, the first and second support strips intersecting perpendicularly to form a mesh surface, the mesh surface having at least one opening; a blocking portion is disposed on the first and / or second support strips, the blocking portion extending toward the inner side of the corresponding opening; and

[0007] An additional layer is provided in the portion of the first and second support bars surrounding the opening to form a solid area. The additional layer is disposed in the solid area and there is a predetermined distance between the additional layer and the inner edge of the opening adjacent to it.

[0008] The additional layer has a higher magnetic permeability than the metal substrate.

[0009] As a further embodiment, the metal substrate is stainless steel, and the additional layer is nickel or Invar alloy;

[0010] Preferably, the metal matrix is ​​304 stainless steel or 316 stainless steel.

[0011] As a further option, the additional layer is a nickel layer plated over the solid region; or,

[0012] The additional layer is an Invar alloy strip, welded to the solid area.

[0013] As a further embodiment, the thickness of the additional layer is less than the thickness of the metal substrate, and not less than one-fifth of the thickness of the metal substrate;

[0014] Preferably, the thickness of the additional layer is between one-third and two-thirds of the thickness of the metal substrate.

[0015] As a further embodiment, the predetermined distance between the additional layer and the inner edge of the adjacent opening is S, where S ≥ 1 mm;

[0016] Preferably, 2mm ≥ S ≥ 1mm.

[0017] As a further option, the additional layer may be multiple independently distributed parts; or,

[0018] The additional layer is a single unit.

[0019] As a further embodiment, the surface of the metal substrate is provided with grooves, and the additional layer is embedded in the grooves; or,

[0020] The additional layer is directly bonded to the surface of the metal substrate on one side facing the incoming material direction.

[0021] As a further option, the metal substrate is a one-piece molded structure; or,

[0022] The first support bar and the second support bar are each manufactured separately, and the first support bar and the second support bar in the mesh are fixedly connected by welding.

[0023] as well as

[0024] The present invention also provides a mask device made using the above-described support mask.

[0025] As a further embodiment, the mask device includes:

[0026] Mask frame; and

[0027] The aforementioned support mask; and

[0028] Fine photomask;

[0029] The support mask and the fine mask are sequentially attached to the mask frame.

[0030] The beneficial effects of this invention are as follows:

[0031] 1) In this invention, a shielding portion for fabricating irregularly shaped screens (such as "waterdrop," "notch," or "blind hole") is provided on a supporting mask. Simultaneously, the supporting mask is configured as a composite structure including a metal substrate and an additional layer with better magnetic permeability than the metal substrate. The additional layer is disposed within a solid area surrounding each opening, providing the main attraction for adhesion between the mask and the substrate. Furthermore, a predetermined distance is maintained between the additional layer and the inner edge of the opening, preventing it from covering the metal substrate at the opening edge. Based on this design, the supporting mask of this invention not only provides support for the fine mask to reduce sagging but also improves the adhesion between the mask and the substrate. This solves the technical problem in traditional vapor deposition processes where poor adhesion and subsequent color mixing defects occur due to the magnetic effect of the shielding portion of the mask. This improves product quality.

[0032] 2) Using the support mask of the present invention as a support, together with the fine mask, can reduce the influence of the support mask on the pattern area of ​​the fine mask, avoid the generation of wrinkles, ensure better adhesion between the pattern area of ​​the fine mask and the substrate, and help improve the pattern accuracy of the fine mask during vapor deposition and improve product quality.

[0033] Furthermore, other additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0034] Figure 1 A schematic diagram of the structure supporting the photomask;

[0035] Figure 2 This is a schematic diagram of the mask frame structure;

[0036] Figure 3 This is a schematic diagram of the structure of a fine photomask;

[0037] Figure 4 This is a schematic diagram showing the distance between the additional layer and the opening edge of the supporting mask.

[0038] Figure 5 A schematic diagram of a structure in which an additional layer is set in a groove supporting a mask;

[0039] Figure 6 Schematic diagrams of two different implementations of the additional layer;

[0040] In the diagram: 1. Mask frame; 10. Window;

[0041] 2. Supporting mask; 20. Opening; 21. Metal substrate; 22. Additional layer; 201. First support strip; 202. Second support strip; 211. Solid area; 212. Masking part; 213. Groove;

[0042] 3. Fine mask; 31. Pattern area; 32. Masking area. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. For reference, the following description and accompanying drawings are brief examples to help understand this invention, and are not intended to limit the technical scope of this invention. In other words, the embodiments described below may have various modifications, which fall within the scope of the technical concept of this invention. Those skilled in the art can easily understand the technical concept of this invention through the following description. The invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] In traditional manufacturing methods for various irregularly shaped screens such as "waterdrop screens," "notch screens," and "blind hole screens," the masking portions corresponding to the "waterdrop," "notch," or "blind hole" areas are typically placed on a fine mask (FMM). In other words, the fine mask is used to mask out the shape of the irregular screen. During the vapor deposition process, the mask adheres to the substrate due to the magnetic force of a magnet. The masking portions on the fine mask are also affected by the magnetic effect, leading to poor adhesion between the masking portions and the substrate. This manifests as color mixing defects in the vapor-deposited product, resulting in a decrease in product yield.

[0045] To address this issue, the industry has adopted a solution where the masking portions corresponding to the "waterdrop," "notch," or "hole-in-the-hole" areas on the screen are placed on a supporting mask below the fine mask. This means the supporting mask masks out the shapes of various irregularly shaped screens such as "waterdrop screens," "notch screens," and "hole-in-the-hole screens," eliminating the need for pre-reserved masking portions on the fine mask itself. However, the research team for this invention discovered during practical application that this mask structure cannot truly solve the color mixing defect problem in irregularly shaped design areas. Further research revealed that while the fine mask itself adheres well to the substrate after removing the masking portions, the masking portions on the supporting mask, when influenced by magnetism, indirectly cause poor adhesion between the corresponding parts of the fine mask and the substrate.

[0046] Furthermore, based on the above attempts, the research team of this invention also tried to perform a half-cut at the edge of the opening of the support mask, in order to minimize the impact of the support mask on the fine mask. However, practical results showed that this improvement was not significantly effective in improving the aforementioned color mixing defects.

[0047] Based on further in-depth research, this invention proposes a supporting mask that can solve the problem of color mixing defects in products caused by poor mask bonding. (Attached) Figure 1 The diagram illustrates one structural form of the support mask of the present invention.

[0048] See appendix Figure 1 As shown, the support mask 2 includes a metal substrate 21, which has a mesh structure and is equipped with multiple first support strips 201 and multiple second support strips 202. The first support strips 201 and the second support strips 202 intersect perpendicularly to form a mesh surface, and the mesh surface has multiple openings 20 penetrating the mesh surface. It is worth noting that the number of openings 20 on the metal substrate 21 can be increased or decreased according to actual needs, and there can be as little as one opening 20.

[0049] In one embodiment of the present invention, the metal substrate 21 constituting the supporting mask 2 adopts an integral molding structure. For example, a whole metal sheet is used as the master plate, and openings 20 are processed on the master plate by etching or other processing methods to form a mesh-like metal substrate 21. Alternatively, the metal sheet can be processed into individual metal strips, with some metal strips arranged horizontally as first support strips 201 and other metal strips arranged vertically as second support strips 202. The first support strips 201 and the second support strips 202 intersect perpendicularly and are welded together at the intersection to form a mesh-like metal substrate 21.

[0050] The metal substrate 21 also has a shielding portion 212, which is used to create irregularly shaped design areas on the irregularly shaped screen, such as "waterdrop," "notch," or "hole-in-the-hole." Therefore, the shape of the shielding portion 212 is basically consistent with the shape of the irregularly shaped design area on the irregularly shaped screen. The shielding portion 212 is located at the corresponding opening 20, and is a portion of the metal substrate 21 protruding inwards from the opening 20, disposed on the support strip. See also... Figure 1 In the embodiment shown, the shielding portion 212 is provided on the second support strip 202. It should be understood that the provision of the shielding portion 212 in this invention is not limited to the attached... Figure 1 As shown, the shielding part 212 can be formed on the second support bar 202, or on the first support bar 201, or partly on the first support bar 201 and partly on the second support bar 202.

[0051] See appendix Figure 1 As shown, the support mask 2 of the present invention further includes an additional layer 22. The portion of the first support strip 201 and the second support strip 202 surrounding the opening 20 constitutes the solid region 211 of the support mask 2. The additional layer 22 is disposed in the solid region 211, and there is a predetermined distance between the additional layer 22 and the inner edge of the opening 20 adjacent to it, so that the additional layer 22 does not cover the metal substrate 21 at the edge of the opening 20.

[0052] Furthermore, the additional layer 22 has a higher magnetic permeability than the metal substrate 21. Magnetic permeability represents the sensitivity of a material to an external magnetic field; the higher the magnetic permeability, the better the sensitivity to an external magnetic field. That is to say, under the action of the magnet plate in the vapor deposition machine, the additional layer 22 is more easily attracted and adheres to the substrate than the metal substrate 21. In the vapor deposition machine, the attraction force supporting the mask 2 and adhering to the substrate is mainly generated by the magnetic attraction of the additional layer 22 to the magnet plate; that is, the additional layer 22 provides the main attraction force for adhering the mask to the substrate. Moreover, since there is a predetermined distance between the additional layer 22 and the inner edge of the opening 20, and it does not cover the metal substrate 21 at the edge of the opening 20, the magnetic influence on the additional layer 22 will not affect the pattern area of ​​the fine mask corresponding to the area of ​​the opening 20 supporting the mask 2.

[0053] Based on this design, the support mask of the present invention can not only provide basic support for the fine mask to reduce the sagging of the fine mask, but also improve the adhesion between the mask and the substrate. This solves the technical problem in the vapor deposition process where poor adhesion and color mixing defects occur due to the magnetic effect of the mask's blocking part. This improves product quality.

[0054] In one embodiment of the present invention, the metal substrate 21 constituting the support mask 2 is stainless steel, preferably 304 stainless steel or 316 stainless steel; the additional layer 22 is metallic nickel, which is processed onto the solid area 211 of the metal substrate 21 by a plating process to form a metallic nickel layer; in addition, the additional layer 22 may also be made of Invar alloy, such as an Invar alloy strip, which is welded to the solid area 211.

[0055] Nickel and Invar alloys have a suitable and relatively significant difference in magnetic permeability compared to stainless steel, especially 304 and 316 stainless steel. The combination of these two materials in this solution is highly effective in resolving the technical problem of poor mask bonding leading to color mixing defects. Furthermore, the primary function of the supporting mask 2 remains to provide support and shielding for the fine mask. The composite structure formed by combining stainless steel with nickel or Invar alloys in this invention has good anti-expansion properties, preventing excessive sagging of the supporting mask 2 and ensuring that its basic support function remains unaffected.

[0056] In a photomask assembly, the supporting photomask 2 serves as a support for the fine photomask, and its sag directly affects the overall sag of the photomask assembly. Within the supporting photomask 2, the additional layer 22 provides the primary magnetic attraction for its adhesion to the substrate. Therefore, the appropriate configuration of the additional layer 22 on the metal substrate 21 directly determines the adhesion capability of the supporting photomask 2 to the substrate. In this application, the width of the additional layer 22 is limited by the widths of the first support strip 201 and the second support strip 202; therefore, the selection of the thickness of the additional layer 22 is particularly important.

[0057] In this application, the thickness of the additional layer 22 is set to be less than the thickness of the metal substrate 21, but not less than one-fifth of the thickness of the metal substrate 21. This effectively ensures the adhesion of the support mask 2 to the substrate caused by the magnetic force of the magnet plate in the vapor deposition machine, reducing the overall sag of the mask assembly. As a more preferred embodiment, the thickness of the additional layer 22 is between one-third and two-thirds of the thickness of the metal substrate 21. This ensures the adhesion of the support mask 2 to the substrate while reducing thermal expansion deformation of the support mask 2. For example, the thickness of the additional layer 22 is one-third, one-half, or two-thirds of the thickness of the metal substrate 21.

[0058] Appendix Figure 4 It is shown that there is a predetermined distance between the additional layer 22 and the edge of the opening 20. Figure 4 (a) shows a partial view of the interface at a certain location in the solid region 211 of the support mask 2. Figure 4 (b) shows a schematic plan view of one arrangement of the additional layer 22 around the opening 20. See Appendix Figure 4 As shown, the predetermined distance S between the additional layer 22 and the inner edge of the adjacent opening 20 is S ≥ 1 mm. This predetermined distance S provides an effective buffer zone between the additional layer 22, the shielding portion 212, and the opening 20. Due to the presence of this buffer zone, the magnetic effect of the magnet plate on the additional layer 22 has virtually no impact on the shielding portion 212, resulting in good adhesion between the mask and the substrate. Furthermore, in the mask assembly, this buffer zone prevents the magnetic force on the additional layer 22 supporting the mask 2 from indirectly affecting the pattern area of ​​the fine mask, thus avoiding wrinkles in the pattern area and ensuring better adhesion between the pattern area of ​​the fine mask and the substrate.

[0059] Generally, the higher the density of the openings 20 in the support mask 2, the higher the effective utilization rate of the mask surface. Correspondingly, the widths of the first support strip 201 and the second support strip 202 will decrease. Based on this consideration, in one embodiment, it is preferable to set the predetermined distance between the additional layer 22 and the inner edge of its adjacent opening 20 between 1 and 2 mm, i.e., 2 mm ≥ S ≥ 1 mm. For example, the predetermined distance S is 1 mm, 1.5 mm, or 2 mm. In this way, when the widths of the first support strip 201 and the second support strip 202 are already small, the width of the additional layer 22 will not be excessively compressed, and the adhesion of the support mask 2 to the substrate generated by the magnetic force of the magnet plate in the vapor deposition machine is guaranteed.

[0060] In some embodiments, the additional layer 22 in the supporting mask 2 may include multiple independently distributed portions, or it may be a single unit. For example, the additional layer... Figure 6 Two different implementations of the additional layer 22 structure are shown in the figure.

[0061] See appendix Figure 6 As shown in (a), the additional layer 22 surrounding each opening 20 is disposed independently on each side of the opening 20, and is not connected to or in contact with each other. Furthermore, throughout the entire support mask 2, the portions of the additional layer 22 surrounding the different openings 20 are also independent of each other. See Appendix Figure 6 As shown in (b), within the entire support mask 2, the various parts of the additional layer 22 are connected to each other to form a whole.

[0062] It is worth noting that, compared to the appendix Figure 6 The example in (a), with appendix Figure 6 The example in (b) has an additional layer 22 that is a monolithic mesh structure, which provides better resistance to thermal expansion in supporting the mask 2. Therefore, having an additional layer... Figure 6 The additional layer 22 shown in (b) has a smaller deformation before and after heating of the support mask 2, and has a smaller impact on the accuracy of the vapor deposition pattern.

[0063] See appendix Figure 5 As shown, a groove 213 is provided on the surface of the metal substrate 21, and an additional layer 22 is embedded in the groove 213, with the additional layer 22 bonded to the inner surface of the groove 213. The groove 213 can be provided on the side surface of the metal substrate 21 facing the material inlet direction, or on the side surface of the metal substrate 21 away from the material inlet direction. Here, the material inlet direction refers to the direction in which the organic material moves towards the metal mask during the vapor deposition process. Generally, in a vapor deposition machine, the organic material is usually placed below the substrate and the metal mask. In this case, the side surface of the metal substrate 21 facing the material inlet direction should refer to the lower surface of the metal substrate 21, and the side surface away from the material inlet direction should refer to the upper surface of the metal substrate 21.

[0064] Because of the presence of the groove 213, setting the additional layer 22 on the metal substrate 21 will not increase the thickness of the support mask 2. In this way, the support mask 2 can maintain a small thickness, thus making it easier to achieve higher precision requirements.

[0065] Furthermore, as another embodiment of the present invention, the additional layer 22 can also be directly bonded to the surface of the metal substrate 21 facing the incoming material direction. For example, the additional layer 22... Figure 4 In the example shown in (a), the additional layer 22 is directly bonded to the lower surface of the metal substrate 21.

[0066] The supporting mask of the present invention has been described in as much detail as possible above, but the present invention is not limited thereto. The present invention also provides a masking device.

[0067] One embodiment of the masking device of the present invention includes the aforementioned supporting mask 2, as well as a mask frame 1 and a fine mask 3. The supporting mask 2 and the fine mask 3 are sequentially joined (there are various joining methods, such as welding) on ​​the mask frame 1.

[0068] See appendix Figure 2 As shown, the mask frame 1 has a vertically continuous window 10 in its center, and the openings 20 in the supporting mask 2 are located within the window 10 in the center of the mask frame 1. Multiple fine mask plates 3 are located above the supporting mask 2; see attached diagram. Figure 3 As shown in (a), the fine mask 3 has a pattern area 31 and a masking area 32. The pattern area 31 corresponds vertically to the opening 20 in the supporting mask 2, and the masking area 32 corresponds vertically to the solid area 211 of the supporting mask 2. It is worth noting that the number of fine masks 3 set in the masking device can be increased or decreased according to needs in different application scenarios, and at least only one fine mask 3 can be set.

[0069] See appendix Figure 3 As shown in (a), in the fine mask 3, the portion of the pattern area 31 corresponding to the shielding portion 212 on the supporting mask 2 and the other portions of the pattern area 31 have etched holes with the same arrangement and density, that is, no shielding structure corresponding to the "water drop", "notch" or "blind hole" part on the irregular screen is provided.

[0070] In addition, there is another implementation method, which differs from the aforementioned implementation method in that, see Appendix Figure 3 As shown in (b), the effective area of ​​the fine mask 3 is etched across the entire surface, and the corresponding masking area 32 has etched holes that are consistent with the pattern area 31. This structure helps to reduce the influence of the magnetic effect on the supporting mask 2 on the fine mask 3, further improves the consistency of the bonding between the various parts of the fine mask 3 and the substrate, and improves the evaporation quality.

[0071] The mask apparatus of the present invention uses the supporting mask provided by the present invention as a support, and is used together with the fine mask. This can reduce the influence of the supporting mask on the pattern area of ​​the fine mask, avoid the generation of wrinkles, ensure better adhesion between the pattern area of ​​the fine mask and the substrate, and help improve the pattern accuracy of the fine mask during vapor deposition and improve product quality.

[0072] Finally, it should be emphasized again that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and not to limit them. Although the embodiments of the present invention have been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the embodiments of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A support mask, characterized in that, include: A metal substrate (21) is provided with a plurality of first support strips (201) and a plurality of second support strips (202). The first support strips (201) and the second support strips (202) intersect perpendicularly to form a mesh surface, and the mesh surface has at least one opening (20). A blocking part (212) is provided on the first support strip (201) and / or the second support strip (202), and the blocking part (212) extends toward the inside of the corresponding opening (20). as well as An additional layer (22) is provided in the solid area (211) formed by the portion of the first support bar (201) and the second support bar (202) surrounding the opening (20). The additional layer (22) is disposed in the solid area (211), and there is a predetermined distance between the additional layer (22) and the inner edge of the opening (20) adjacent to it, the predetermined distance being 1mm to 2mm. The additional layer (22) has a higher magnetic permeability than the metal substrate (21). Wherein, the metal substrate (21) is stainless steel, and the additional layer (22) is nickel or Invar alloy. Among them, nickel is processed onto the solid area (211) to form a metallic nickel layer by plating process, or an Invar alloy strip is made and welded to the solid area (211); The thickness of the additional layer (22) is less than the thickness of the metal substrate (21) and not less than one-fifth of the thickness of the metal substrate (21).

2. The supporting mask according to claim 1, characterized in that, The metal matrix (21) is 304 stainless steel or 316 stainless steel.

3. The supporting mask according to claim 1, characterized in that, The thickness of the additional layer (22) is between one-third and two-thirds of the thickness of the metal substrate (21).

4. The supporting mask according to claim 1, characterized in that, The additional layer (22) consists of multiple independently distributed parts; or, The additional layer (22) is a single unit.

5. The supporting mask according to claim 1, characterized in that, The surface of the metal substrate (21) is provided with a groove (213), and the additional layer (22) is embedded in the groove (213); or, The additional layer (22) is directly bonded to the side surface of the metal substrate (21) facing the incoming material direction.

6. The supporting mask according to claim 1, characterized in that, The metal substrate (21) is a one-piece molded structure; or, The first support bar (201) and the second support bar (202) are each individually manufactured, and the first support bar (201) and the second support bar (202) in the mesh are fixedly connected by welding.

7. A masking device made using the support mask as described in any one of claims 1 to 6.

8. The masking device according to claim 7, characterized in that, include: Mask frame (1); as well as The aforementioned support mask; as well as Fine mask (3); The support mask and the fine mask (3) are sequentially attached to the mask frame (1).

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