Mask plate assembly

Abstract

The invention provides a mask plate assembly, comprising: a mask plate having an evaporation surface and a non-evaporation surface arranged back to back, the evaporation surface being used for facing a substrate to be evaporated, the mask plate comprising a plurality of pixel openings and a non-opening part; the supporting framework is arranged on one side of the non-evaporation surface of the mask plate and is configured to be used for assisting the mask plate to be attached to the substrate to be evaporated under the action of magnetic adsorption force in the evaporation process; wherein the supporting framework comprises a plurality of hollowed-out parts and framework parts located between the hollowed-out parts, each hollowed-out part corresponds to N pixel openings in the mask plate, the framework parts correspond to and support the non-opening parts, and N is a positive integer larger than or equal to 2. The mask plate assembly provided by the invention can improve the defects of evaporation shadow and the like.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more particularly to a mask assembly. Background Technology

[0002] OLED (Organic Light-Emitting Diode) displays are considered a promising next-generation display technology due to their advantages such as thinness, light weight, wide viewing angle, active emission, continuously adjustable emission color, low cost, fast response speed, low power consumption, low driving voltage, wide operating temperature range, simple manufacturing process, high luminous efficiency, and flexible display capabilities. With the rapid development of OLED display technology, high pixel density (PPI) and low pixel definition layer gap (PDL Gap) have become key indicators for improving display performance. The fine metal mask (FMM), as a core component in the OLED evaporation process, directly affects the yield and display effect of the display panel. Summary of the Invention

[0003] In order to solve at least one of the technical problems in the prior art, embodiments of this application provide a mask assembly.

[0004] To solve the above-mentioned technical problems, this application is implemented as follows:

[0005] This disclosure provides a mask assembly, including:

[0006] A photomask has a vapor deposition surface and a non-vapor deposition surface arranged opposite to each other, the vapor deposition surface being used to face the substrate to be vapor-deposited, and the photomask includes multiple pixel openings and non-opening portions;

[0007] A support frame is disposed on the non-evaporation surface side of the photomask and is configured to assist the photomask in adhering to the substrate to be evaporated under the action of magnetic attraction during the evaporation process; wherein,

[0008] The supporting skeleton includes multiple hollow portions and a skeleton portion located between the hollow portions. Each hollow portion corresponds to N pixel openings on the mask template. The skeleton portion corresponds to and supports the non-opening portions, where N is a positive integer greater than or equal to 2.

[0009] For example, in a first direction perpendicular to the vapor deposition surface, the thickness of the mask is less than or equal to the thickness of the support frame.

[0010] For example, in a first direction perpendicular to the vapor deposition surface, the thickness of the support frame is 30-50 micrometers.

[0011] For example, the plurality of pixel openings include a plurality of pixel units, each pixel unit including n pixel openings, where N≥9n.

[0012] For example, the mask template includes a plurality of mask strips, and at least in the width direction of the mask strips, the edge of the support skeleton extends beyond the edge of the mask template to enhance the magnetic attraction at the edge position of the mask template.

[0013] For example, the distance by which the edge of any side of the support frame extends beyond the corresponding edge of the mask template is 0.5~1mm.

[0014] For example, the mask template is provided with a first alignment pattern, and the support frame is provided with a second alignment pattern at a position corresponding to the first alignment pattern, and the center of the second alignment pattern coincides with the center of the first alignment pattern.

[0015] For example, the photomask is provided with a pixel position calibration area and / or a film thickness measurement area, and the support frame is provided with an avoidance cutout corresponding to the pixel position calibration area and / or the film thickness measurement area.

[0016] For example, the mask template has multiple single-screen areas, each single-screen area is provided with multiple pixel openings distributed in an array, and the non-opening portion includes an inter-screen bridging portion located between adjacent single-screen areas and an inter-pixel bridging portion located between adjacent pixel openings within the single-screen area;

[0017] The support skeleton includes multiple support units, each support unit corresponding to one single-screen area, and the edge of the support unit extends outward relative to the edge of the single-screen area. Each support unit has multiple cutout portions arranged in an array. The skeleton portion includes an inter-screen skeleton portion located between adjacent support units and an inter-pixel skeleton portion located between adjacent cutout portions within the support unit. The inter-screen skeleton portion corresponds to and supports the inter-screen bridging portion, and the inter-pixel skeleton portion corresponds to and supports the inter-pixel bridging portion.

[0018] For example, the plurality of pixel openings in each of the single screen areas include real pixel openings and virtual pixel openings. The real pixel openings are provided in the effective display area of ​​the single screen area, and the plurality of virtual pixel openings are provided at the four corners of the single screen area. A third alignment pattern is also provided at the four corners of the single screen area.

[0019] The orthographic projection of the hollow portion within the support unit onto the vapor deposition surface falls entirely within the range of the actual pixel opening and the third alignment pattern in the corresponding single-screen area; the support unit has a fourth alignment pattern at the outer side of the single-screen area and at the corresponding four corner positions, the fourth alignment pattern being a hollow pattern with an area smaller than that of the hollow portion.

[0020] The embodiments disclosed herein offer at least the following beneficial effects:

[0021] In the mask assembly provided in this embodiment, a support skeleton is provided on the non-evaporation surface of the mask. The hollow part of the support skeleton corresponds to N pixel openings on the mask, and the skeleton part of the support skeleton corresponds to and supports the non-opening part on the mask. Each hollow part covers N pixel openings, where N is greater than or equal to 2. In this way, it can be ensured that the pixel openings are not blocked, and the support skeleton can generate magnetic attraction force with the electromagnetic field during the evaporation process, so that the mask and the substrate to be evaporated are tightly attached, thereby reducing problems such as evaporation shadows caused by poor adhesion between the mask and the substrate to be evaporated. Attached Figure Description

[0022] Figure 1 This is a schematic diagram showing the bonding of the photomask assembly and the substrate to be vapor-deposited in the embodiments of this application;

[0023] Figure 2 This is a structural schematic diagram of the mask template assembly during the netting process provided in the embodiments of this application;

[0024] Figure 3 This is one of the structural schematic diagrams of a single support strip and a single mask strip combination in the mask assembly provided in the embodiments of this application;

[0025] Figure 4 This is a partial structural diagram of the support frame and mask strip in the mask assembly provided in the embodiments of this application;

[0026] Figure 5 for Figure 3 A schematic diagram of a local structure where one side edge of the central support frame extends beyond the edge of the mask strip;

[0027] Figure 6 for Figure 3 A partial structural diagram of region E within the dashed box;

[0028] Figure 7 for Figure 3 A partial structural diagram of the area within the dashed box F;

[0029] Figure 8 This is a second schematic diagram of the structure of a single support strip and a single mask strip combination in the mask assembly provided in this application embodiment;

[0030] Figure 9 for Figure 8 A schematic diagram of a local structure where one side edge of the central support frame extends beyond the edge of the mask strip;

[0031] Figure 10 for Figure 8 A partial structural diagram of the area within the dashed box H;

[0032] Figure 11 for Figure 8 A partial structural diagram of region I within the dashed box;

[0033] Figure 12 for Figure 8 A schematic diagram of the partial structure of region J within the dashed box. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "a" or "one," and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked," and similar terms, are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0036] Before providing a detailed description of the mask assembly provided in the disclosed embodiments, the related technology will be described below.

[0037] With the rapid development of OLED display technology, high pixel density (PPI) and low pixel definition layer gap (PDL Gap) have become key indicators for improving display performance. The fine metal mask (FMM), as a core component in the OLED evaporation process, directly affects the yield and display effect of the display panel. However, technological advancements have led to a decrease in yield. For example, problems such as evaporation shadows exist in the evaporation process.

[0038] The inventors of this publication have discovered, through research, that some of the reasons for the aforementioned problems are as follows:

[0039] First, high PPI design leads to abnormal vapor deposition shadows: To meet high PPI requirements, the aperture density of fine metal masks needs to be continuously increased, which usually requires reducing the thickness of the mask (FMM sheet). During the vapor deposition process, thinner masks, due to their insufficient rigidity, are difficult to be completely attracted by a magnetic field, resulting in abnormal adhesion between the mask and the substrate to be vapor deposited, forming vapor deposition shadows. These shadows affect the yield and display effect of the display panel.

[0040] Secondly, abnormal evaporation shadows caused by special pixel designs: For Real RGB or other special pixel designs, the length of a single pixel is relatively long, making it easier for excessive shadows to occur during the evaporation process. This is because the longer pixel structure makes it more difficult for the mask and substrate to adhere during evaporation, resulting in uneven deposition of the evaporation material and the formation of obvious evaporation shadow areas.

[0041] Third, the design of dummy cells at the edge of the photomask introduces the risk of foreign matter (particles): In related technologies, to address abnormal evaporation shadows, dummy cells containing openings are designed at the edge of the entire photomask to facilitate adsorption. However, the presence of these edge areas often leads to the introduction of foreign matter due to environmental factors, causing poor color mixing in localized areas.

[0042] Fourth, insufficient adhesion at the corners of the single-screen area leads to abnormal vapor deposition shadows: To improve the aesthetics of the product, the single-screen area on the photomask may have a large chamfer design. However, this large chamfer will cause uneven stress on the entire photomask in the horizontal and vertical directions, resulting in abnormal adhesion at the corners of the single-screen area and abnormal vapor deposition shadows.

[0043] Based on this, the present disclosure provides a mask assembly that can improve problems such as vapor deposition shadows caused by poor adhesion between the mask and the substrate to be vaporized.

[0044] like Figures 1 to 4 As shown, the mask assembly provided in this embodiment includes:

[0045] A photomask 100 has a vapor deposition surface 110 and a non-vapor deposition surface 120 disposed opposite to each other. The vapor deposition surface 110 is used to face the substrate 10 to be vapor-deposited. The photomask 100 includes a plurality of pixel openings 101 and non-opening portions 102.

[0046] A support frame 200 is disposed on the non-evaporation surface 120 side of the mask 100 and is configured to assist the mask 100 in adhering to the substrate 10 to be evaporated under the action of magnetic attraction during the evaporation process; wherein,

[0047] The support frame 200 includes a plurality of cutout portions 201 and a frame portion 202 located between the cutout portions 201. Each cutout portion 201 is provided corresponding to N pixel openings 101 on the mask template 100. The frame portion 202 corresponds to and supports the non-opening portion 102, where N is a positive integer greater than or equal to 2.

[0048] In the above scheme, the photomask 100 can be a fine metal photomask (FMM). A support frame 200 is provided on the non-evaporation surface 120 side of the photomask 100, with the cutout portion 201 of the support frame 200 corresponding to N pixel openings 101 on the photomask 100. The frame portion 202 of the support frame 200 corresponds to and supports the non-opening portion 102 on the photomask 100. Each cutout portion 201 can cover the range of N pixel openings 101, where N is greater than or equal to 2. This ensures that the pixel openings are not obstructed. Simultaneously with the opening 101, the support frame 200 provides additional rigid support for the mask 100, compensating for insufficient rigidity of the mask 100 due to high PPI design, etc., and the frame portion 202 supports the non-opening portion 102, so that during the evaporation process, the support frame 200 generates a magnetic attraction force with the electromagnetic field, causing the mask 100 to be tightly attached to the substrate 10 to be evaporated under the action of the magnetic attraction force, thereby significantly reducing problems such as evaporation shadows caused by poor adhesion between the mask 100 and the substrate 10 to be evaporated.

[0049] Furthermore, due to the provision of the support frame 200, the mask 100 and the substrate 10 to be vaporized can be tightly fitted together, thereby eliminating the need to design virtual opening areas at the edge of the mask 100, which can reduce the risk of foreign matter introduction, avoid localized poor mixing, and improve vaporization yield.

[0050] Furthermore, since the hollow portion 201 corresponds to N pixel openings 101, this modular structural design can enhance the overall support of the entire photomask 100, flexibly adapt to high PPI, Real RGB, or other special pixel arrangement designs, breaking through the limitations of traditional photomasks 100 on pixel structure, enhancing process compatibility, and increasing design freedom. Simultaneously, for photomasks 100 with large chamfers on a single screen, the support frame 200 does not require a large chamfer design, eliminating the problem of uneven stress at the chamfer. This enhances the adhesion between the photomask 100 and the substrate 10 to be vapor-deposited at the chamfer, thereby avoiding abnormal vapor deposition shadows caused by abnormal adhesion at the corners of the single-screen area.

[0051] In some exemplary embodiments, in a first direction perpendicular to the vapor deposition surface 110, the thickness of the mask 100 is less than or equal to the thickness of the support frame 200.

[0052] In the above scheme, since the function of the support frame 200 is to provide rigid support for the mask 100 during the evaporation process and to tightly bond the mask 100 to the substrate 10 to be evaporated using magnetic attraction, the support frame 200 needs to have sufficient structural strength to compensate for the insufficient rigidity caused by the small thickness of the mask 100. Therefore, the thickness of the support frame 200 can be greater than or equal to the thickness of the mask 100, so that the support frame 200 has better bending stiffness and can provide more effective structural support for the mask 100 under the action of magnetic attraction, preventing the mask 100 from undergoing local deformation or warping due to insufficient rigidity, thereby ensuring uniform bonding between the mask 100 and the substrate 10 to be evaporated. Furthermore, a thicker support frame 200 can more effectively distribute the magnetic attraction force evenly to all areas of the mask 100, especially the area between the pixel openings 101, avoiding abnormal bonding caused by insufficient local magnetic attraction force.

[0053] For example, in the first direction perpendicular to the vapor deposition surface 110, the thickness of the support frame 200 is 30-50 micrometers. The selection of the thickness range of the support frame 200 needs to match the thickness of the mask 100. For example, the mask 100 is generally thin, such as 8-30 μm, and the support frame 200 needs to have sufficient thickness to provide rigid support; therefore, the thickness of the support frame 200 can be set to 30 μm or more. If the thickness of the support frame 200 is too thin, the support will be insufficient; however, if the thickness of the support frame 200 is too thick, it may affect the penetration effect of the magnetic field. When the thickness of the support frame 200 is 30-50 micrometers, it can match the magnetic field strength to ensure the magnetic field penetration effect while also ensuring support strength.

[0054] Furthermore, the thickness of the support frame 200 must ensure that it does not interfere with the deposition angle of the vapor-deposited material. Within the aforementioned thickness range, the sidewalls of the support frame 200 will not obstruct the deposition path of the vapor-deposited material. For example, taking the minimum vapor deposition angle of 62° in the current vapor deposition process as an example, the thickness design of the support frame 200 can ensure that the vapor-deposited material can be deposited onto the substrate 10 to be vapor-deposited through the pixel opening 101 at the correct angle, avoiding problems such as vapor deposition shadows or uneven film thickness caused by interference from the support frame 200. For example, when the thickness of the mask 100 is 30 μm, the thickness of the support frame 200 can be 50 μm. As another example, when the thickness of the mask 100 is 8 μm, the thickness of the support frame 200 can be 30 μm. Of course, it is understood that the specific thickness of the support frame 200 is not limited to these values.

[0055] In some exemplary embodiments, such as Figure 4 As shown, the plurality of pixel openings include a plurality of pixel units, and each pixel unit includes n pixel openings, where N≥9n, and n is greater than or equal to 2. The hollow portion 201 of the support frame 200 needs to be fabricated through patterning processes such as photolithography, and each hollow portion 201 corresponds to more than 9 pixel units. This design ensures that the size of the hollow portion 201 is within the controllable range of the process, neither being too small to cause manufacturing difficulties, nor too large to cause a decrease in support effect.

[0056] For example, the value of N can be in the range of (9~36)n, meaning that each of the cutout portions 201 covers 9 to 36 pixel units. This ensures that each cutout portion 201 covers at least a 3*3 pixel unit array. The skeleton portion 202 surrounding the cutout portion 201 can form a support area of ​​a certain size, effectively blocking the stress generated by the mask 100 during the vapor deposition process within each independent support area, preventing stress from being conducted and diffused throughout the entire mask 100. Furthermore, when the value of N is in the range of (9~36)n, the size of the cutout portion 201 corresponding to this range of pixel openings 101 is within the optimal controllable range of photolithography, etching, and other processes, ensuring manufacturing accuracy. The coverage range of the cutout portion 201 with 9~36 pixel units also provides good design flexibility, adapting to different pixel arrangements. For example, in the design of elongated pixels such as Real RGB, the coverage area of ​​the cutout portion 201 of 9 to 36 pixel units can also combine multiple elongated pixels into a single support area, effectively improving the deformation caused by uneven stress between the openings 101 of the elongated pixels. It is understood, however, that in practical applications, the value of N is not limited to this.

[0057] In addition, such as Figure 2As shown, the mask template 100 includes multiple mask strips 130. For example, the mask template 100 can be formed by splicing multiple mask strips 130 into a single mask template 100. Each mask strip 130 can be a long strip with a certain extension length, and the opposite ends of the mask strip 130 in the length direction are welded and fixed to the frame 20 during mesh stretching. Figure 3 As shown, along the length of the mask strip 130, the mask strip 130 is divided into a middle region A and an extension region B located at both ends. The pixel openings 101 are distributed in the middle region A. A first cutting line is provided on the opposite sides of the middle region A. After the mesh is stretched, the ends of the extension region B can be cut off along the first cutting line.

[0058] In some exemplary embodiments of this disclosure, such as Figure 3 As shown, one support frame 200 is provided corresponding to one mask strip 130. The shape of the support frame 200 is adapted to the mask strip 130. A second cutting line a is provided on the support frame 200 at a position corresponding to the first cutting line. The second cutting line a can be formed by a half-cutting process. After the screen is stretched, the end of the support frame 200 can be cut off along the second cutting line a.

[0059] Furthermore, during the vapor deposition process, the edges of the mask 100 are prone to problems such as poor adhesion and warping due to the lack of support from adjacent structures, resulting in abnormal edge vapor deposition shadows. In the prior art, virtual opening areas are set in the edge region of the entire mask 100 to enhance edge adsorption; however, the design of virtual opening areas can introduce impurities, causing abnormal edge vapor deposition shadows.

[0060] In some exemplary embodiments of this disclosure, at least in the width direction of the mask strip 130, the edge of the support skeleton 200 extends beyond the edge of the mask template 100. This edge-extension design allows the support skeleton 200 to extend beyond a portion of the edge of the mask template 100, providing additional points of magnetic attraction and thus enhancing the magnetic attraction at the edge of the mask template 100. This prevents edge warping of the mask template 100 and improves the edge-fitting effect of the mask template 100.

[0061] Furthermore, the edge of the support frame 200 extends beyond the edge of the mask template 100, which is equivalent to adding a support platform below the edge of the mask template 100, forming a protective enclosure for the mask template 100, significantly increasing the overall rigidity of the edge area of ​​the mask template 100, ensuring the stability of the overall structure, and preventing deformation of the edge area of ​​the mask template 100.

[0062] In some exemplary embodiments, such as Figure 5 and Figure 9 As shown, the distance by which the edge b of any side of the support frame 200 extends beyond the corresponding edge c of the mask template 100 is 0.5~1mm. Setting the distance d of the support frame 200 extending beyond the mask template 100 on one side to 0.5~1mm allows for enhanced edge magnetic adhesion without interfering with surrounding structures. This distance range is within the controllable precision range of the mesh alignment process, achieving a stable edge extension effect without increasing the difficulty of mesh alignment due to excessive extension. This extension distance allows the support frame 200 to adequately wrap around the mask template 100. It is understood that the specific value of the extension distance is not limited to this.

[0063] It should be noted that the portion of the support frame 200 extending beyond the edge of the mask template 100 can all be solid material, eliminating the risk of impurity introduction caused by setting virtual opening areas in related technologies. For example, in some embodiments, the support frame 200 has a middle region A and an edge region B in the width direction. The hollow portion 201 is provided in the middle region A, while the hollow portion 201 is not provided in the edge region B. The dimension D of the edge region B in the width direction can be greater than or equal to 0.5 mm. For example, the distance D between the edge of the edge region B and the boundary of the middle region A can be approximately 0.9 mm or 0.6 mm to further ensure the adhesion of the edge region.

[0064] Since the support frame 200 is located on the non-evaporation surface 120 side of the mask 100, each of the cutout portions 201 covers N pixel openings 101, and the frame portion 202 needs to correspond to the non-opening area, extremely high requirements are placed on the relative positional accuracy of the two. During the screen stretching process, the mask 100 and the support frame 200 need to be stretched and fixed synchronously. If there is no precise alignment, relative displacement may occur between the two, causing the cutout portion 201 and the pixel opening 101 to be misaligned.

[0065] Therefore, in some exemplary embodiments, such as Figure 5 and Figure 8 As shown, the mask template 100 is provided with a first alignment pattern T1, and the support frame 200 is provided with a second alignment pattern T2 at a position corresponding to the first alignment pattern T1. The second alignment pattern T2 can be adapted to the shape of the first alignment pattern T1, and the center of the second alignment pattern T2 coincides with the center of the first alignment pattern T1. In this way, alignment patterns are provided on both the mask template 100 and the support frame 200, and the alignment centers coincide. Using the center of the alignment pattern as the alignment reference, alignment errors caused by differences in pattern shape can be avoided.

[0066] For example, the first alignment pattern T1 can be a first alignment hole, and correspondingly, the second alignment pattern T2 is a second alignment hole, with their centers overlapping. For example, the first alignment hole can be any suitable shape such as a circle or a cross, making it easy to identify and locate. Exemplarily, the second alignment hole is designed to expand outwards relative to the first alignment hole to avoid obstructing it.

[0067] For example, both the second alignment pattern and the first alignment pattern may include a coarse alignment mark T11. There may be two coarse alignment marks T11, respectively located on opposite sides of the mask template 100 and the support frame 200 in the width direction, and they are centrally symmetrical. For example, one side of the coarse alignment mark T11 may be a circular hole, and the other side of the coarse alignment mark T12 may be an elliptical hole.

[0068] For example, in some embodiments, the thickness of the support frame 200 is 50 μm, and the thickness of the mask 100 is 30 μm. The diameter of the circular coarse alignment mark T11 hole on the support frame 200 can be 2 mm, and the size of the elliptical coarse alignment mark T11 hole can be 4*2 mm. The distance between the circular and elliptical coarse alignment mark T11 holes in the longitudinal direction is 550 mm. The size of the coarse alignment mark T11 hole on the mask 100 is 1 mm smaller than the size of the coarse alignment mark T11 hole on the support frame 200. However, this is not a limitation.

[0069] For example, in some embodiments, the thickness of the support frame 200 is 30 μm, and the thickness of the mask 100 is 8 μm. The diameter of the circular coarse alignment mark T11 hole on the support frame 200 can be 2 mm, and the size of the elliptical coarse alignment mark T11 hole can be 4*2 mm. The distance between the circular and elliptical coarse alignment mark T11 holes in the longitudinal direction is 550 mm. The size of the coarse alignment mark T11 hole on the mask 100 is 1 mm smaller than the size of the coarse alignment mark T11 hole on the support frame 200. However, this is not a limitation.

[0070] In addition, such as Figure 8 and Figure 10 As shown, both the second alignment pattern T2 and the first alignment pattern T1 may further include a fine alignment mark T12. The mask 100 has multiple single-screen areas, and there may be multiple fine alignment marks T12, which are spaced apart adjacent to the sides of each single-screen area and in the width direction of the mask 100.

[0071] For example, in some embodiments, the thickness of the support frame 200 is 50 μm, and the thickness of the mask 100 is 30 μm. The spacing between adjacent alignment marks T12 in the width direction (longitudinal direction) of the mask 100 can be 17 mm, and the spacing between adjacent alignment marks T12 in the length direction (lateral direction) of the mask 100 can be 352 mm, with at least one set of alignment marks T12 located on the transverse centerline of the entire mask 100. For example, the alignment marks T12 on the mask 100 are circular holes with a diameter of 0.2 mm. The alignment marks T12 on the support frame 200 are extended outwards relative to the alignment marks T12 on the mask 100.

[0072] For example, in some embodiments, the thickness of the support frame 200 is 30 μm, and the thickness of the mask 100 is 8 μm. The spacing between adjacent alignment marks T12 in the width direction (longitudinal direction) of the mask 100 can be 17 mm, and the spacing between adjacent alignment marks T12 in the length direction (lateral direction) of the mask 100 can be 352 mm, with at least one set of alignment marks T12 located on the transverse centerline of the entire mask 100. For example, the alignment marks T12 on the mask 100 are circular holes with a diameter of 0.2 mm. The alignment marks T12 on the support frame 200 are extended outwards relative to the alignment marks T12 on the mask 100.

[0073] It should be understood that the above is merely an example and is not intended to be limiting. In the above scheme, by setting coarse alignment mark T11 and fine alignment mark T12, the overall positional accuracy can be ensured through multi-point alignment.

[0074] Furthermore, in some exemplary embodiments, such as Figure 3 and Figure 7 ,like Figure 8 and Figure 12The photomask 100 is provided with a pixel position calibration area and / or a film thickness measurement area (PPA Teg). The pixel position calibration area and / or film thickness measurement area (PPA Teg) are critical areas used in the vapor deposition process for monitoring or calibrating the position of deposited pixels or the thickness of the film. The support frame 200 is provided with a clearance cutout 203 corresponding to the pixel position calibration area and / or film thickness measurement area. The clearance cutout 203 is a localized cutout design for the critical measurement and / or calibration areas, which does not affect the overall structural function of the support frame 200 and requires no modification to the existing process, ensuring that the measurement or calibration function of the original pixel position calibration area and / or film thickness measurement area (PPA Teg) is not interfered with. For example, the orthographic projection of the clearance cutout 203 and the pixel position calibration area and / or film thickness measurement area on the vapor deposition surface 110 can completely coincide.

[0075] Furthermore, in some exemplary embodiments, such as Figures 3 to 11 As shown, the mask template 100 has multiple single-screen areas A1, each of which has multiple pixel openings 101 arranged in an array. The non-opening portion 102 includes an inter-screen bridging portion 1021 located between adjacent single-screen areas A1 and an inter-pixel bridging portion 1022 located between adjacent pixel openings 101 within a single-screen area A1. The support skeleton 200 includes multiple support units A2, each support unit A2 corresponding to one single-screen area A1. Each support unit A2 has multiple hollow portions 201 arranged in an array. The skeleton portion 202 includes an inter-screen skeleton portion 2021 located between adjacent support units A2 and an inter-pixel skeleton portion 2022 located between adjacent hollow portions 201 within a support unit A2. The inter-screen skeleton portion 2021 corresponds to and supports the inter-screen bridging portion 1021, and the inter-pixel skeleton portion 2022 corresponds to and supports the inter-pixel bridging portion 1022.

[0076] In the above scheme, the photomask 100 is divided into multiple single-screen areas A1, each of which corresponds to a display screen unit, such as a mobile phone screen or a watch screen. Each single-screen area A1 has multiple pixel openings 101 arranged in an array. The connection area between adjacent single-screen areas A1 is considered an inter-screen bridging part 1021, and the connecting ribs between adjacent pixel openings 101 within the same single-screen area A1 are considered inter-pixel bridging parts 1022. The support frame 200 is divided into multiple support units A2, with one support unit A2 corresponding to one single-screen area A1. The inter-screen frame 2021 corresponds to and supports the inter-screen bridging parts 1021 to ensure the overall structural stability of the entire photomask 100 during the screen stretching and vapor deposition processes. The inter-pixel frame 2022 corresponds to and supports the inter-pixel bridging parts 1022, ensuring that the connecting parts around the pixel openings 101 are accurately supported, preventing local collapse.

[0077] In some exemplary embodiments, the width of the inter-pixel skeleton portion 2022 is smaller than the width of the inter-pixel bridging portion 1022. For example, the width of the inter-pixel skeleton portion 2022 is 10-20 nm smaller than the width of the inter-pixel bridging portion 1022, that is, the inter-pixel skeleton portion 2022 is recessed by 5-10 nm from one side edge of the inter-pixel bridging portion 1022. The width of the inter-screen skeleton portion 2021 is smaller than the width of the inter-screen bridging portion 1021. For example, the width of the inter-screen skeleton portion 2021 is 10-20 nm smaller than the width of the inter-screen bridging portion 1021, that is, the inter-screen skeleton portion 2021 is recessed by 5-10 nm from one side edge of the inter-screen bridging portion 1021.

[0078] In this way, during the mesh alignment process of the double-layer composite structure of the mask template 100 and the support frame 200, even if there is a slight alignment deviation, the thinner frame portion 202 can still ensure that it falls completely within the range of the bridging portion, preventing the frame portion 202 from extending into the pixel opening 101 area; furthermore, the thinner frame portion 202 has less impact on the deposition path of the vapor deposition material, ensuring that the vapor deposition angle is not affected; in addition, while ensuring the support function, the weight of the support frame 200 is reduced as much as possible, reducing the impact on the mesh tension.

[0079] Furthermore, in some exemplary embodiments, such as Figure 8 and Figure 11As shown, each of the single-screen areas A1 contains multiple pixel openings 101, including real pixel openings (not shown in the figure) and virtual pixel openings 101b. The real pixel openings are provided in the effective display area of ​​the single-screen area A1, and multiple virtual pixel openings 101b are provided at the four corners of the single-screen area A1. A third alignment pattern T3 is also provided at the four corners of the single-screen area A1. The orthographic projection of the hollow portion 201 in the support unit A2 onto the vapor deposition surface 110 falls completely within the range of the real pixel openings and the third alignment pattern T3 in the corresponding single-screen area A1. The support unit A2 provides a fourth alignment pattern T4 on the outside of the single-screen area A1 and at the corresponding four corners. The fourth alignment pattern T4 is a hollow pattern and its area is smaller than the area of ​​the hollow portion 201.

[0080] In the above scheme, the pixel openings 101 located in the single-screen area A1 can be divided into real pixel openings and virtual pixel openings 101b. Real pixels are pixel units that are actually used for light emission, and the hollowed-out portion 201 of the support frame 200 must completely correspond to these real pixel openings. Virtual pixels are located at the four corner positions and are auxiliary non-light-emitting pixel units used to play auxiliary functions such as stress relief.

[0081] For the actual pixel opening, it can be set to correspond with the cutout portion 201 to ensure that no solid part of the supporting frame 200 extends into the actual pixel opening area, thus avoiding obstruction of the light-emitting area. For the virtual pixel opening 101b, which is a non-light-emitting area, it can be set to correspond with or not be aligned with the cutout portion 201.

[0082] For high PPI designs, more precise positioning is required. Therefore, a third alignment pattern T3 can be set at the four corners of each single-screen area A1. Figure 11 As shown, the third alignment pattern T3 on the mask 100 can be set in the area where the virtual pixel opening 101b is located, and the third alignment pattern T3 can include three circular alignment holes. Due to the structure, the mask 100 may also have uneven stress at the chamfer position, which in turn leads to abnormal vapor deposition shadows at the four corners.

[0083] The third alignment pattern T3 is correspondingly set in the cutout portion 201 within the support unit A2. Even if the third alignment pattern T3 is located within the cutout portion 201, it can be directly avoided by the cutout portion 201. A fourth alignment pattern T4 is provided on the outer side of the single-screen area A1 at the corresponding four corner positions. The fourth alignment pattern T4 is a cutout pattern with an area smaller than that of the cutout portion 201. For example, the area of ​​the fourth alignment pattern T4 can be one-quarter of the area of ​​the cutout portion 201. In this way, the smaller cutout area makes it easier to identify the fourth alignment pattern T4 and allows more solid material to be retained at the four corner positions of the support frame 200, avoiding weakening of the corner structure due to large-area cutouts, thereby improving stress uniformity at the corner positions.

[0084] Furthermore, for example, the fourth alignment pattern T4 can be rectangular. The corner structure of a rectangular pattern helps to evenly distribute the stress at the four corners along two perpendicular directions, avoiding stress concentration. Moreover, for designs with large chamfers, the rectangular pattern can better adapt to the stress state at the chamfer, reducing stress unevenness caused by the chamfer design. Please see the appendix. Figure 11 As shown, in some embodiments, the distance between the fourth alignment pattern T4 and its adjacent cutout portion 201 is the same in both the horizontal and vertical directions, in order to further ensure uniform corner stress.

[0085] Furthermore, in some embodiments of this disclosure, since the support frame is relatively thick, the hollow portions on the support frame can be formed by patterning both sides of the support frame, such as by double-sided etching. Referring to the figures, the hollow portions formed by double-sided etching have an inner diameter that gradually decreases and then gradually increases along the direction from the vapor-deposited surface to the non-vapor-deposited surface. It is understood, of course, that the structure of the hollow portions is not limited to this.

[0086] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, since the embodiments are basically similar to the product embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the product embodiments.

[0087] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0088] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

[0089] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A mask assembly, characterized in that, include: A photomask has a vapor deposition surface and a non-vapor deposition surface arranged opposite to each other. The vapor deposition surface is used to face the substrate to be vapor deposited. The photomask includes a plurality of pixel openings and non-opening portions. and A support frame is disposed on the non-evaporation surface side of the photomask and is configured to assist the photomask in adhering to the substrate to be evaporated under the action of magnetic attraction during the evaporation process; wherein, The supporting skeleton includes multiple hollow parts and a skeleton part located between the hollow parts. Each hollow part corresponds to N pixel openings on the mask template. The skeleton part corresponds to and supports the non-opening parts, where N is a positive integer greater than or equal to 2.

2. The mask assembly according to claim 1, characterized in that, In a first direction perpendicular to the vapor deposition surface, the thickness of the mask is less than or equal to the thickness of the support frame.

3. The mask assembly according to claim 2, characterized in that, In a first direction perpendicular to the vapor deposition surface, the thickness of the support frame is 30-50 micrometers.

4. The mask assembly according to claim 1, characterized in that, The plurality of pixel openings comprises a plurality of pixel units, each pixel unit comprising n pixel openings, wherein N≥9n.

5. The mask assembly according to claim 1, characterized in that, The mask template includes multiple mask strips, and at least in the width direction of the mask strips, the edge of the support skeleton extends beyond the edge of the mask template to enhance the magnetic attraction at the edge position of the mask template.

6. The mask assembly according to claim 5, characterized in that, The distance by which the edge of any side of the support frame extends beyond the corresponding edge of the mask template is 0.5~1mm.

7. The mask assembly according to claim 1, characterized in that, The mask template is provided with a first alignment pattern, and the support frame is provided with a second alignment pattern at the position corresponding to the first alignment pattern, and the center of the second alignment pattern coincides with the center of the first alignment pattern.

8. The mask assembly according to claim 1, characterized in that, The mask template is provided with a pixel position calibration area and / or a film thickness measurement area, and the support frame is provided with an avoidance cutout corresponding to the pixel position calibration area and / or film thickness measurement area.

9. The mask assembly according to claim 1, characterized in that, The mask template has multiple single-screen areas, and each single-screen area is provided with multiple pixel openings arranged in an array. The non-opening portion includes an inter-screen bridging portion located between adjacent single-screen areas and an inter-pixel bridging portion located between adjacent pixel openings within the single-screen area. The support skeleton includes multiple support units, one support unit corresponds to one single screen area, and each support unit has multiple cutouts arranged in an array. The skeleton part includes an inter-screen skeleton part located between adjacent support units and an inter-pixel skeleton part located between adjacent cutouts within the support unit. The inter-screen skeleton portion corresponds to and supports the inter-screen bridging portion, and the inter-pixel skeleton portion corresponds to and supports the inter-pixel bridging portion.

10. The mask assembly according to claim 9, characterized in that, Each of the single-screen areas has multiple pixel openings, including real pixel openings and virtual pixel openings. The real pixel openings are provided in the effective display area of ​​the single-screen area, and multiple virtual pixel openings are provided at the four corners of the single-screen area. A third alignment pattern is also provided at the four corners of the single-screen area. The orthographic projection of the hollow portion within the support unit onto the vapor deposition surface falls entirely within the range of the actual pixel opening and the third alignment pattern in the corresponding single-screen area; the support unit has a fourth alignment pattern at the outer side of the single-screen area and at the corresponding four corner positions, the fourth alignment pattern being a hollow pattern with an area smaller than that of the hollow portion.

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