Method for controlling tensile force of mask and method for manufacturing frame-integrated mask

Abstract

The present invention relates to a method for controlling mask tensile force and a method for manufacturing a frame-integrated mask. According to one embodiment of the present invention, the method for controlling mask tensile force during the manufacturing process of a frame-integrated mask in which a frame and multiple masks are connected is used to control the mask tensile force. The method comprises the following steps: (a) determining the internal stress distribution in the thickness direction of a mask metal film manufactured by a rolling process; (b) reducing the thickness of at least one side of the mask metal film based on the internal stress distribution in the thickness direction; and (c) preparing a mask by forming multiple mask patterns on the mask metal film.

Description

Technical Field

[0001] The present invention relates to a method for controlling the tensile force of a mask and a method for manufacturing a frame-integrated mask. Background Art

[0002] As a technology for forming pixels in the OLED manufacturing process, the FMM (Fine Metal Mask) method is mainly used. In this method, a thin film metal mask (shadow mask) is attached to a substrate and organic matter is deposited at a desired position.

[0003] In the existing OLED manufacturing process, after the mask is manufactured into a strip shape, a plate shape, etc., the mask is welded and fixed to the OLED pixel deposition frame and used. A mask can have multiple units corresponding to one display. In addition, in order to manufacture large-area OLEDs, multiple masks can be fixed to the OLED pixel deposition frame. During the process of fixing them to the frame, each mask is stretched to make it flat. Adjusting the stretching force to make the entire part of the mask flat is a very difficult task. In particular, in order to flatten each unit while aligning the mask pattern with a size of several to tens of μm, the following difficult task is required: finely adjusting the stretching force applied to each side of the mask while confirming the alignment status in real time.

[0004] Despite this, the process of securing multiple masks to a single frame still presents problems with poor alignment between masks and between mask units. Furthermore, during the process of welding the masks to the frame, the mask film is too thin and has a large surface area, causing the mask to sag or twist under the load. Furthermore, wrinkles and burrs generated at the welded parts during welding can lead to misalignment of the mask units.

[0005] Among ultra-high-definition OLEDs, existing QHD resolution is 500-600 PPI (pixels per inch), with pixel sizes reaching approximately 30-50 μm. 4K UHD and 8K UHD high-definition resolutions reach even higher, reaching resolutions of 860 PPI and 1600 PPI, respectively. Given the pixel size of ultra-high-definition OLEDs, alignment errors between units must be reduced to a few μm. Exceeding this error will result in defective products, potentially leading to extremely low yields. Therefore, it is necessary to develop technologies that can prevent mask deformation, such as sagging or twisting, and ensure precise alignment, as well as technologies for securing the mask to a frame. Summary of the Invention

[0006] Technical problems to be solved

[0007] Therefore, the object of the present invention is to provide a mask tensile force control method and a frame-integrated mask manufacturing method that can manufacture a frame-integrated mask according to the internal stress distribution of the mask metal film and use a part that matches the required tensile force in order to solve the many problems of the prior art as described above.

[0008] Another object of the present invention is to provide a method for controlling tensile force of a mask and a method for manufacturing a frame-integrated mask, which can apply tensile force by utilizing internal stress without directly applying tensile force to the side surfaces of the mask.

[0009] However, the above technical problems are only exemplary, and the scope of the present invention is not limited thereto.

[0010] Technical Solution

[0011] The above-mentioned purpose of the present invention can be achieved by a method for controlling the tensile force of a mask, which is used to control the tensile force of a mask during the manufacturing process of a frame-integrated mask in which a frame and multiple masks are connected, and includes the following steps: (a) determining the internal stress distribution in the thickness direction of a mask metal film manufactured by a rolling process; (b) reducing the thickness of at least one side of the mask metal film according to the internal stress distribution in the thickness direction; (c) preparing a mask by forming multiple mask patterns on the mask metal film.

[0012] The step (b) is performed by any one of the following methods (1) to (3): (1) reducing the mask metal film of a preset thickness from the upper surface, (2) reducing the mask metal film of a preset thickness from the lower surface, (3) reducing the mask metal film of a preset thickness from both the upper surface and the lower surface.

[0013] Regarding (3), the thicknesses reduced from the upper face and the lower face may be different from each other.

[0014] In the step (c), a plurality of the mask patterns may be formed in a state where the mask metal film is bonded to a template with a temporary bonding portion interposed therebetween.

[0015] In the step (a), the upper and lower portions of the mask metal film based on the thickness direction may include compressive stress regions, and the middle portion may include a tensile stress region.

[0016] In the step (b), the greater the ratio of the compressive stress interval to the tensile stress interval in the reduced-thickness mask metal film, the greater the tensile force on the template toward the side surface of the mask.

[0017] In the step (b), in the mask metal film with reduced thickness, if the ratio of the compressive stress interval is greater than the ratio of the tensile stress interval, then after the step (c), the mask may be bonded to the template in a state of being further stretched toward at least one side compared to the initial design value.

[0018] In the step (b), in the mask metal film with reduced thickness, if the ratio of the tensile stress interval is greater than the ratio of the compressive stress interval, then after the step (c), the mask may be bonded to the template in a state of being further contracted toward at least one side compared to the initial design value.

[0019] In addition, the above-mentioned purpose of the present invention can be achieved by a manufacturing method of a frame-integrated mask, which is formed by integrating a mask for forming OLED pixels and a frame, including the following steps: (a) determining the internal stress distribution in the thickness direction of a mask metal film manufactured by a rolling process; (b) bonding the mask metal film to a template with a temporary bonding portion in the middle; (c) reducing the thickness of at least one side of the mask metal film according to the internal stress distribution in the thickness direction; (d) preparing a mask by forming multiple mask patterns on the mask metal film; and (e) connecting the mask to a frame.

[0020] The method may further include the step of (f) separating the template from the mask.

[0021] In the step (a), the upper and lower parts of the mask metal film based on the thickness direction include compressive stress intervals, and the middle part includes a tensile stress interval. In the step (b), the greater the ratio of the compressive stress interval to the tensile stress interval in the mask metal film with reduced thickness is, the greater the tensile force on the template toward the side direction of the mask.

[0022] In the step (b), the tension applied by the mask to the frame after the step (f) is controlled by controlling the ratio of the compressive stress region to the tensile stress region in the mask metal film with reduced thickness.

[0023] Effects of the Invention

[0024] According to the present invention having the above structure, there is an effect that a frame-integrated mask can be manufactured using a portion that matches a required tensile force according to the internal stress distribution of the mask metal film.

[0025] Furthermore, according to the present invention, there is an effect that a tensile force can be exerted by utilizing internal stress rather than directly applying a tensile force to the side surfaces of the mask {exerting a tensile force by utilizing internal stress}.

[0026] Of course, the scope of the present invention is not limited by the above-mentioned effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of an existing process of attaching a mask to a frame.

[0028] Figure 2 1 and 2 are front and side views of a frame-integrated mask according to an embodiment of the present invention.

[0029] Figure 3 is a schematic diagram of a mask according to an embodiment of the present invention.

[0030] Figures 4 and 5 FIG. 1 is a schematic diagram of a process of forming a mask to manufacture a mask support template by bonding a mask metal film to a template according to an embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram illustrating a problem that occurs when the thermal expansion coefficient of the template is higher than that of the mask according to a comparative example.

[0032] Figure 7 3 is a schematic diagram illustrating an interface state between the mask and the template and a state where the mask is attached to a frame when the thermal expansion coefficient of the template is lower than that of the mask according to an embodiment of the present invention.

[0033] Figure 8 FIG. 1 is a schematic diagram illustrating the extension state of a mask metal film and a template in response to a process temperature change according to an embodiment of the present invention.

[0034] Figure 9 1 is a comparison data between the initial design dimensions of the mask and the dimensions after the process is completed according to an experimental example of the present invention.

[0035] Figure 10 FIG. 4 is a schematic diagram of a method for measuring the total pitch of a mask before and after a process according to an experimental example of the present invention.

[0036] Figure 11 FIG. 1 is a schematic diagram of a state in which a template is carried on a frame and a mask is aligned with a unit area of ​​the frame according to an embodiment of the present invention.

[0037] Figure 12 FIG. 1 is a schematic diagram illustrating a process of separating the mask from the template after attaching the mask to the frame according to an embodiment of the present invention.

[0038] Figure 13 FIG. 1 is a schematic diagram illustrating a state where a mask is attached to a unit region of a frame according to an embodiment of the present invention.

[0039] Figure 14 FIG. 1 is a schematic diagram of a process of manufacturing a mask metal film using a rolling process according to an embodiment of the present invention.

[0040] Figure 15Schematic diagram of an internal stress model of a mask metal film manufactured by a rolling process and a state where the mask metal film and a template are bonded according to an embodiment of the present invention.

[0041] Figure 16 FIG. 4 is a schematic diagram illustrating a change in the total pitch (TP) of a mask according to an embodiment of the present invention.

[0042] Figure 17 FIG. 1 is a schematic diagram of TP changes before and after the mask is welded to the frame according to an embodiment of the present invention.

[0043] Figure 18 FIG. 1 is a schematic diagram of the stretching amount in each step based on a stable state after the mask is welded to the frame according to an embodiment of the present invention.

[0044] Figure 19 FIG. 1 is a schematic diagram of a method for using a mask metal film to match a tensile force according to an embodiment of the present invention.

[0045] Figure 20 FIG. 1 is a schematic diagram of a process of reducing the thickness of at least one side of a mask metal film based on the internal stress distribution of the mask metal film according to an embodiment of the present invention.

[0046] Figure 21 FIG. 1 is a schematic diagram of the internal stress distribution state in the tensile direction and the width direction of the mask metal film manufactured by the rolling process according to one embodiment of the present invention.

[0047] Figure 22 FIG. 1 is a schematic diagram of a sample of a mask applicable based on internal stress distribution according to an embodiment of the present invention.

[0048] Figure 23 yes Figure 22 Comparison data of the sample's mask's initial design dimensions and dimensions after processing.

[0049] Figure 24 yes Figure 22 A graph showing the required stretching of the mask side based on the internal stress distribution of the sample. DETAILED DESCRIPTION

[0050] Below, the present invention is described in detail with reference to the accompanying drawings, which are used to illustrate examples of specific embodiments that can be implemented as the present invention. These embodiments are described in detail so that those skilled in the art can fully implement the present invention. The various embodiments of the present invention should be understood to be different from each other but not exclusive. For example, the specific shapes, structures and characteristics described herein can be implemented as other embodiments of one embodiment without exceeding the spirit and scope of the present invention. In addition, the position or arrangement of the individual components in each disclosed embodiment should be understood to be subject to change without exceeding the spirit and scope of the present invention. Therefore, the following detailed description is not intended to limit the present invention. As long as it can be properly explained, the scope of the present invention is limited only by the attached claims and all scopes equivalent thereto. Similar figure numbers in the drawings refer to the same or similar functions in various aspects. For convenience, length, area, thickness, etc. and their forms may also be exaggerated.

[0051] Hereinafter, in order to enable those skilled in the art to easily implement the present invention, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0052] Figure 1 is a schematic diagram of an existing process of attaching a mask to a frame.

[0053] The existing mask 10 is a stick-type or plate-type. Figure 1 The strip mask 10 can be welded onto an OLED pixel deposition frame on both sides for use. The main body (or mask film 11) of the mask 10 has multiple display cells C. Each cell C corresponds to a display on a smartphone, etc. A pixel pattern P is formed in each cell C to correspond to each pixel of the display.

[0054] Reference Figure 1 (a), a tensile force F1-F2 is applied along the long axis direction of the strip mask 10, and the strip mask 10 is loaded on the frame 20 in the unfolded state. The cells C1-C6 of the strip mask 10 will be located in the blank area inside the frame 20.

[0055] Reference Figure 1 (b), the tensile forces F1-F2 applied to the respective sides of the strip mask 10 are finely adjusted while being aligned, and then the strip mask 10 and the frame 20 are connected to each other by welding a portion of the side surface of the strip mask 10 W. Figure 1 (c) shows a side section of the stripe type mask 10 and the frame connected to each other.

[0056] Despite fine-tuning the tensile forces F1-F2 applied to each side of the strip mask 10, the problem of poor alignment between the mask units C1-C3 still occurs. For example, the distances between the patterns P of the units C1-C6 are different from each other or the patterns P are skewed. Since the strip mask 10 has a large area including a plurality of units C1-C6 and has a very thin thickness of tens of μm, it is easy to sag or twist due to the load. In addition, it is a very difficult task to adjust the tensile forces F1-F2 to make all the units C1-C6 flat while confirming the alignment status between the units C1-C6 in real time through a microscope. However, in order to avoid the mask pattern P with a size of several μm to tens of μm from having a bad influence on the pixel process of the ultra-high-definition OLED, the alignment error is preferably not more than 3 μm. The alignment error between such adjacent units is called pixel position accuracy (PPA).

[0057] Furthermore, it is a very difficult task to connect each strip mask 10 to a frame 20 respectively and to accurately align the multiple strip masks 10 and the multiple units C-C6 of the strip mask 10. This will only increase the process time based on alignment, thereby becoming an important reason for reducing production efficiency.

[0058] Furthermore, after the strip mask 10 is connected and fixed to the frame 20, the tensile force F1-F2 applied to the strip mask 10 acts inversely on the frame 20. This tension causes the frame 20 to deform slightly and the alignment between the cells C-C6 to be distorted.

[0059] In view of this, the present invention proposes a frame 200 and a frame-integrated mask that can form an integrated structure of the mask 100 and the frame 200. The mask 100 integrated with the frame 200 can not only prevent deformation such as sagging or twisting, but also can be accurately aligned with the frame 200.

[0060] Figure 2 This is a front view of a frame-integrated mask according to an embodiment of the present invention. Figure 2 (a)] and side cross-sectional view [ Figure 2 (b)].

[0061] Although this specification describes the configuration of the frame-integrated mask, the structure and manufacturing process of the frame-integrated mask can be understood as including the entire content of Korean Invention Patent Application No. 2018-0016186.

[0062] Reference Figure 2A frame-integrated mask can include multiple masks 100 and a frame 200. In other words, multiple masks 100 are attached to the frame 200. For ease of explanation, a square mask 100 is used as an example. However, before the mask 100 is attached to the frame 200, it can be a strip-shaped mask with protrusions on both sides for clamping. After attachment to the frame 200, the protrusions can be removed.

[0063] A plurality of mask patterns P are formed on each mask 100, and one cell C can be formed on one mask 100. One mask cell C can correspond to one display of a smartphone or the like.

[0064] The mask 100 may also be made of materials such as invar, super invar, nickel (Ni), nickel-cobalt (Ni-Co), etc. The mask 100 may be made of a metal sheet produced by rolling or electroforming.

[0065] The frame 200 can be formed to attach multiple masks 100. Considering thermal deformation, the frame 200 is preferably formed from a material such as Invar, Super Invar, nickel, or nickel-cobalt that has the same thermal expansion coefficient as the masks. The frame 200 can include a substantially quadrilateral or square edge frame portion 210. The interior of the edge frame portion 210 can be hollow.

[0066] In addition, the frame 200 includes a plurality of mask unit regions CR and may include a mask unit sheet portion 220 connected to the edge frame portion 210. The mask unit sheet portion 220 may be composed of an edge sheet portion 221, a first grid sheet portion 223, and a second grid sheet portion 225. The edge sheet portion 221, the first grid sheet portion 223, and the second grid sheet portion 225 are sections formed on the same sheet and are integrally formed.

[0067] The thickness of the edge frame portion 210 can be greater than that of the mask unit sheet portion 220, and can be formed with a thickness of several millimeters to several centimeters. Although thinner than the edge frame portion 210, the mask unit sheet portion 220 is thicker than the mask 100, and can be approximately 0.1 mm to 1 mm thick. The width of the first grid sheet portion 223 and the second grid sheet portion 225 can be approximately 1-5 mm.

[0068] In the planar sheet, a plurality of mask unit regions CR ( CR11 - CR56 ) may be provided in addition to the regions occupied by the edge sheet portion 221 , the first grid sheet portion 223 , and the second grid sheet portion 225 .

[0069] The mask 200 includes multiple mask cell regions CR, and each mask 100 can be attached so that each mask cell C corresponds to each mask cell region CR. The mask cells C correspond to the mask cell regions CR of the frame 200, and part or all of the dummy portion can be attached to the frame 200 (mask cell sheet 220). Thus, the mask 100 and frame 200 can form an integrated structure.

[0070] Figure 3 is a schematic diagram of a mask 100 according to an embodiment of the present invention.

[0071] The mask 100 may include a mask cell C having a plurality of mask patterns P formed therein and a dummy portion DM surrounding the mask cell C. The mask 100 may be manufactured using a metal sheet produced by a rolling process, electroforming, or the like, and may include a single cell C therein. The dummy portion DM corresponds to the portion of the mask film 110 (mask metal film 110) excluding the cell C and may include only the mask film 110 or the mask film 110 formed with a predetermined dummy portion pattern similar in form to the mask pattern P. The dummy portion DM corresponds to the edge of the mask 100, and a portion or all of the dummy portion DM may be attached to the frame 200 (mask cell sheet portion 220).

[0072] The width of the mask pattern P may be less than 40 μm, and the thickness of the mask 100 may be approximately 5-20 μm. Since the frame 200 includes a plurality of mask cell regions CR (CR11-CR56), it may also include a plurality of masks 100, each having a mask cell C (C11-C56) corresponding to each mask cell region CR (CR11-CR56).

[0073] Reference Figure 4 (a) A template 50 may be provided. The template 50 is a medium having the mask 100 attached to one side thereof and supporting the mask 100 so as to allow the mask 100 to move. One side of the template 50 is preferably a flat surface to support and transport the flat mask 100. The center portion 50a may correspond to the mask cell C of the mask metal film 110, and the edge portion 50b may correspond to the dummy portion DM of the mask metal film 110. In order to support the mask metal film 110 as a whole, the template 50 has a flat shape with an area larger than the mask metal film 110.

[0074] In order to enable the laser L irradiated from the upper part of the template 50 to reach the welding part WP (the area where welding is performed) of the mask 100, a laser through hole 51 may be formed on the template 50. The laser through hole 51 can be formed on the template 50 in a manner corresponding to the position and number of the welding part WP. Since a plurality of welding parts WP are arranged at preset intervals on the edge or dummy part DM of the mask 100, a plurality of laser through holes 51 can also be formed at preset intervals accordingly. As an example, since a plurality of welding parts WP are arranged at preset intervals on the dummy part DM on both sides (left / right) of the mask 100, a plurality of laser through holes 51 can also be formed on both sides (left / right) of the template 50 at preset intervals.

[0075] The position and number of laser holes 51 do not necessarily correspond to the position and number of welded portions WP. For example, laser light L may be irradiated only at a portion of laser holes 51 to perform welding. Furthermore, the portion of laser holes 51 not corresponding to welded portions WP can also serve as alignment marks when aligning mask 100 and template 50. If the material of template 50 is transparent to laser light L, laser holes 51 may not be formed.

[0076] A temporary adhesive portion 55 may be formed on one side of the template 50. Before the mask 100 is attached to the frame 200, the temporary adhesive portion 55 may temporarily attach the mask 100 (or the mask metal film 110) to one side of the template 50 and support the mask 100.

[0077] The temporary adhesive portion 55 may be an adhesive that is releasable by heating or an adhesive that is releasable by UV irradiation.

[0078] As an example, the temporary bonding portion 55 can use liquid wax. Liquid wax can use the same wax used in the polishing step of semiconductor wafers, etc., and its type is not particularly limited. As a resin component mainly used to control the adhesion, impact resistance, etc. related to the maintenance force, liquid wax can include substances and solvents such as acrylic acid, vinyl acetate, nylon and various polymers. As an example, the temporary bonding portion 55 can use SKYLIQUIDABR-4016 including acrylonitrile butadiene rubber (ABR) as a resin component and n-propyl alcohol as a solvent component. Liquid wax is formed on the temporary bonding portion 55 using a spin coating method.

[0079] The temporary adhesive portion 55 as liquid wax has its viscosity reduced at temperatures above 85°C-100°C, and its viscosity increased at temperatures below 85°C, with a portion being solidified, thereby fixing and bonding the mask metal film 110 to the template 50 .

[0080] Secondly, refer to Figure 4(b) The mask metal film 110 may be bonded to the template 50. Liquid wax may be heated to above 85°C, and the mask metal film 110 may be brought into contact with the template 50, and then the mask metal film 110 and the template 50 may be passed between rollers for bonding.

[0081] According to one embodiment, the template 50 is baked at approximately 120°C for 60 seconds to vaporize the solvent in the temporary adhesive portion 55, after which the mask metal film lamination process can be performed immediately. Lamination is performed by placing the mask metal film 110 on the template 50, which has the temporary adhesive portion 55 formed on one side, and passing the mask metal film 110 between an upper roller at approximately 100°C and a lower roller at approximately 0°C. As a result, the mask metal film 110 can contact the template 50 with the temporary adhesive portion 55 interposed therebetween.

[0082] After the mask metal film 110 is bonded to the template 50, one side of the mask metal film 110 may be flattened. The thickness of the mask metal film 110 manufactured by the rolling process can be reduced by the flattening process. In addition, the mask metal film 110 manufactured by the electroforming process may be flattened to control its surface properties and thickness. In addition, the mask metal film 110 may be flattened before being bonded to the template 50. The thickness of the mask metal film 110 may be approximately 5 μm to 20 μm.

[0083] Furthermore, when the mask metal film 110 is formed by etching, it is important to prevent the etching solution from entering the interface between the mask metal film 110 and the temporary bonding portion 55 to damage the temporary bonding portion 55 / template 50, thereby causing etching errors in the mask pattern P. Therefore, the mask metal film 110 is bonded to the upper surface of the template 50 with the first insulating portion 23 formed on one surface of the mask metal film 110. Specifically, the surface of the mask metal film 110 on which the first insulating portion 23 is formed can face the upper surface of the template 50. The mask metal film 110 and the template 50 can be bonded to each other with the first insulating portion 23 and the temporary bonding portion 55 interposed therebetween.

[0084] The first insulating portion 23 can be formed on the mask metal film 110 by a printing method or the like using a photoresist material that is not etched by an etching solution. In addition, in order to maintain a circular shape after multiple wet etching processes, the first insulating portion 23 can include at least one of a curable negative photoresist and a negative photoresist containing an epoxy resin. As an example, it is preferred to use an epoxy resin-based SU-8 photoresist or a black matrix photoresist to achieve the baking of the temporary bonding portion 55 and the baking of the second insulating portion 25 (see Figure 5 (c)) and the like are solidified together.

[0085] Due to the material properties of the first insulating portion 23, even if the second insulating portion 25 is formed [refer to Figure 5 (c)] and subsequent etching processes will not be dissolved by the etching solution. If the first insulating portion 23 is not present, the etching solution can enter the interface between the damaged temporary adhesive portion 55 and the mask metal film 110, further etching the lower portion of the first mask pattern P, which will cause the pattern size to be too large or a local amorphous defect. With the further inclusion of the first insulating portion 23 in the present invention, during the process of forming the mask pattern P using multiple processes, even if the mask metal film 110 is penetrated, the pattern width will not further expand, thereby maintaining the pattern width of the insulating portion 25.

[0086] Although the first insulating portion 23 and the temporary adhesive portion 55 are shown as being formed on the upper surface of the template 50, they may be formed on the lower surface of the mask metal film 110. In addition, the first insulating portion 23 and the temporary adhesive portion 55 may be formed on the template 50 and the mask metal film 110, respectively.

[0087] Then, refer to Figure 5 In (c), a patterned insulating portion 25 (second insulating portion 25) can be formed on the mask metal film 110. The insulating portion 25 can be formed of photoresist using a printing method or the like.

[0088] Next, the mask metal film 110 can be etched. Dry etching, wet etching, or other methods can be used without limitation. As a result of the etching, portions of the mask metal film 110 exposed from the empty spaces 26 between the insulating portions 25 can be etched away. The etched portions of the mask metal film 110 form mask patterns P, thereby manufacturing a mask 100 having a plurality of mask patterns P formed therein.

[0089] Then, refer to Figure 5 In step (d), the manufacturing of the template 50 supporting the mask 100 can be completed by removing the insulating portion 25 (second insulating portion).

[0090] in addition, Figure 5 Although the process of forming the mask pattern P after the mask metal film 110 is bonded to the template 50 is described in (d), it is not limited thereto and can be Figure 4 (a) and (b) will form a mask 100 with a mask pattern P (refer to Figure 3 ) is bonded to the template 50, thereby completing the manufacture of the template 50 for supporting the mask 100.

[0091] Since the frame 200 has a plurality of mask cell regions CR (CR11-CR56), it can also have a plurality of masks 100, each of which has a mask cell C (C11-C56) corresponding to each mask cell region CR (CR11-CR56). In addition, a plurality of templates 50 can be provided, each of which is used to support each of the plurality of masks 100.

[0092] Figure 6 This is a schematic diagram illustrating a problem that occurs when the thermal expansion coefficient of the template is higher than that of the mask according to a comparative example.

[0093] Reference Figure 6 (a) The process temperature of the space where the mask metal film 110 (or mask 100) and the template 50' are bonded is raised to a temperature T1 higher than room temperature. The process temperature T1 may be 85°C to 100°C, which reduces the viscosity of the temporary bonding portion 55. Next, the solvent in the temporary bonding portion 55 is vaporized by baking, and the mask metal film 110 is bonded to the template 50'. The process temperature can then be lowered to a temperature T2, which increases the viscosity of the temporary bonding portion 55 and allows a portion of it to solidify.

[0094] In the past, glass, borosilicate glass, etc. were used as the material of the template 50'. The thermal expansion coefficient is about 3.3X10 -6 / ℃, and its thermal expansion coefficient is about 1.5-3X10 -6 The thermal expansion coefficient difference of the invar mask metal film 110 of 0.1 / °C is small, and the mask metal film 110 is easy to control, so it is often used.

[0095] The thermal expansion coefficient of the template 50' is higher than that of the mask metal film 110. Figure 6 As shown in (a), when the temperature T2 is lowered, the degree of contraction L2 of the mask metal film 110 due to the temperature change is relatively small. Conversely, the degree of contraction L1 of the template 50' relative to the template 50' is large (L1>L2). Simultaneously, the template 50' and the mask metal film 110 are firmly bonded together with the temporary bonding portion 55 interposed therebetween. A force CT is applied to the mask metal film 110, which compresses it further than the original degree of contraction L2. This force CT is generated because the degree of contraction L1 of the template 50' is greater than the degree of contraction L2 of the mask metal film 110. Consequently, the mask metal film 110 is bonded to the template 50' with a compressive force CT applied to the side (inside the mask metal film 110).

[0096] If the thermal expansion coefficient of the template 50 ′ is higher than that of the mask 100 (or the mask metal film 110 ), the following problem may occur.

[0097] Reference Figure 6 (b), by Figure 6 The template 50' of (a) is loaded onto the frame 200 (or the edge sheet portion 221, the first grid sheet portion 223 and the second grid sheet portion 225) so as to correspond to the mask 100, and weld beads WB are formed by welding, so that the mask 100 can be attached to the frame 200.

[0098] Furthermore, the template 50' can be separated from the mask 100. However, when the template 50' is separated from the mask 100, the compressive force CT applied to the mask 100 is released, causing the alignment of the mask 100 to be disrupted. In other words, the mask 100 cannot be attached to the frame 200 with both sides pulled outward tightly, but instead becomes wrinkled or droopy. This can lead to product defects due to errors in the alignment of the mask 100 and PPA errors between cells C.

[0099] Therefore, the template 50 of the present invention has a characteristic of having a lower thermal expansion coefficient than the mask 100 (or the mask metal film 110 ).

[0100] Figure 7 3 is a schematic diagram illustrating an interface state between the mask and the template and a state where the mask is attached to a frame when the thermal expansion coefficient of the template is lower than that of the mask according to an embodiment of the present invention.

[0101] Reference Figure 7 (a), such as Figure 6 As shown in (a), the process temperature of the space where the process is performed is raised to a temperature T1 higher than room temperature, and the mask metal film 110 (or the mask 100 with the pattern P formed thereon) is bonded to the template 50. Then, the process temperature can be lowered to a temperature T2 at which the viscosity of the temporary bonding portion 55 increases and a portion of the temporary bonding portion 55 can be solidified.

[0102] Mask metal 110 (or mask 100) is made of a material such as Invar, Super Invar, nickel, or nickel-cobalt, with a thermal expansion coefficient greater than 1. Conversely, the thermal expansion coefficient of template 50 can be less than 1 (greater than 0). Preferably, template 50 can be made of quartz with a thermal expansion coefficient of 0.55, but is not limited thereto.

[0103] Since the thermal expansion coefficient of the template 50 is lower than that of the mask metal film 110, Figure 7 As shown in (a), when the temperature T2 is lowered, the template 50 hardly shrinks or shrinks to a relatively smaller extent than the mask metal film 110. The shrinkage degree of the mask metal film 110 [shrinkage Figure 7Although the L2 degree in (a) is relatively large, the mask metal film 110 is firmly bonded to the template 50 by the temporary bonding portion 55, and thus cannot shrink and is subjected to an internal force IT that tends to shrink. In other words, the mask metal film 110 is subjected to a lateral tensile force IT and is bonded to the template 50 in a taut state.

[0104] Reference Figure 7 (b) Figure 6 In state (a), the template 50 is loaded onto the frame 200 (or the edge sheet portion 221, the first grid sheet portion 223 and the second grid sheet portion 225) so as to correspond to the mask 100, and welding beads WB are formed by welding, so that the mask 100 can be bonded to the frame 200.

[0105] Furthermore, the template 50 can be separated from the mask 100. However, when the template 50' is separated from the mask 100, the tensile force IT applied to the mask 100 is released and converted into a tension TS that tightens both sides of the mask 100. In other words, this state is a state in which the mask 100 is stretched to a length longer than the original length at the drop temperature T2 of the mask 100 and then adhered to the template 50. Since it is welded and bonded to the frame 200 intact in this state, it can maintain the stretched state (the state in which the mask 100 applies tension TS to the surrounding mask unit sheet portion 220). The mask 100 is attached to the frame 200 in a stretched state, so that wrinkles and deformations will not occur. Therefore, it has the effect of reducing the alignment error of the mask 100 and the PPA error between the units C.

[0106] Figure 8 FIG. 1 is a schematic diagram illustrating the extension state of the mask metal film 110 and the template 50 in response to process temperature changes according to an embodiment of the present invention.

[0107] In addition, if Figure 7 Although the internal force IT (or tensile force IT) can be applied to the mask metal film 110 (or mask 100) by setting the thermal expansion coefficient of the template 50 to be lower than the thermal expansion coefficient of the mask metal film 110, the temperature rise required to bond the mask metal film 110 to the template 50 is 85-100°C. Within this range, the difference in the degree of thermal expansion between the template 50 and the mask metal film 110 is not large, and the bonding is performed under a condition in which the bonding strength of the temporary bonding portion 55 is sufficiently large. Therefore, there is a limitation that the tensile force IT contained in the mask metal film 110 is not large.

[0108] Therefore, the present invention is characterized in that Figure 8 As shown, compared Figure 7 In an embodiment, the process temperature is further controlled to further increase the stretching of the mask metal film 110 or the stretching force IT. Figure 8In (a), in order to compare the expansion and contraction degrees of the mask metal film 110 and the template 50 , their initial lengths are the same, but the initial length of the template 50 may be greater than or equal to that of the mask metal film 110 .

[0109] Reference Figure 8 (a) Prepare a template 50 and a mask metal film 110 (or a mask 100 having a mask pattern P formed thereon) at room temperature (RT) of about 25° C. The first insulating portion 23 and the temporary adhesive portion 50 may be formed on one side of the template 50 or / and the mask metal film 110 .

[0110] Next, refer to Figure 8 (b) The process temperature can be raised to a first process temperature TS1 at which the push-pull strength of the temporary adhesive portion 55 becomes 0 to 5 kgf / cm2. The first process temperature TS1 can be approximately 110-200°C. When the temporary adhesive portion 55 is 0 to 5 kgf / cm2 at the first process temperature TS1, the temporary adhesive portion 55 is in a state where it does not have the adhesive force to bond the mask metal film 110 and the template 50. In other words, it is difficult to bond the mask metal film 110 and the template 50 when the temporary adhesive portion 55 is non-adhesive. This state can be understood as a state where the mask metal film 110 and the template 50 can be easily separated even without applying a load or external force. Therefore, even if the temporary adhesive portion 55 (and the first insulating portion 23) are sandwiched between them, there is only contact between the mask metal film 110 and the template 50, but no adhesion. The mask metal film 110 is not hindered by the temporary adhesive portion 55 and extends linearly as the temperature rises. In addition, the thermal expansion coefficient of the mask metal film 110 is smaller than that of the template 50 , and thus the extension L1 of the mask metal film 110 may be greater than the extension L2 of the template 50 at the first process temperature TS1 .

[0111] Next, refer to Figure 8 In step (c), while the mask metal film 110 is in contact with the template 50, the process temperature can be lowered to a second process temperature TS2. At the second process temperature TS2, the adhesive strength of the temporary adhesive portion 55 is at least greater than 5 kgf / cm2. The second process temperature TS2 can be less than 85-100°C and greater than room temperature. As the temporary adhesive portion 55 exhibits adhesive strength at the second process temperature TS2, the mask metal film 110 and the template 50 can be bonded. As the temperature decreases, the template 50 can shrink (L2->L3), and the mask metal film 110 will shrink accordingly.

[0112] only, Figure 8When the process temperature decreases from step (b) to step (c) (TS1->TS2), the temporary bonding portion 55 is cooled and solidified first, while the temperature decrease rate of the mask metal film 110 is delayed compared to the temporary bonding portion 55. Figure 7 In the case of the mask metal film 110, the mask metal film 110 can be bonded to the template 50 in a further extended state. In other words, compared to the case of the mask metal film 110 Figure 7 When the mask metal film 110 and the template 50 are bonded after the temperature is immediately raised to the second process temperature TS2 at room temperature RT, as shown in FIG. Figure 8 By further increasing the temperature to the first process temperature TS1 between room temperature T and the second process temperature TS2, the mask metal film 110 can be bonded to the template 50 in a further extended state. When the mask metal film 110 and the template 50 are bonded immediately after the temperature is raised to the second process temperature TS2 from room temperature RT, the mask metal film 110 is resisted by the temporary bonding portion 55 due to the considerable adhesive force. Consequently, even with the temperature increase, the mask metal film 110 does not undergo linear extension. This further extension of the mask metal film 110 corresponds to a further increase in the tensile force IT inherent in the mask metal film 110 (or mask 100) supported by the template 50. This means that the mask 100 can remain more taut after it is aligned with / attached to the frame 200 in a subsequent process.

[0113] Next, refer to Figure 8 (e) The process temperature can be lowered to room temperature RT. As the temperature drops, the template 50 shrinks (around L3), and the mask metal film 110 also shrinks accordingly. The template 50 can be restored to Figure 8 The length of the mask metal film 110 at the initial room temperature RT state is greater than the length of the mask metal film 110 at the initial room temperature RT state. The extent of the extension L5 and the tensile force IT contained in the mask metal film 110 are greater than Figure 7 to the extent described in .

[0114] In addition, Figure 8 Between step (c) and step (e), a process of lowering the process temperature to a process temperature TS3 lower than the room temperature RT may be further performed. Then, the temperature may be raised to the room temperature RT again. As the temperature is lowered to the process temperature TS3, the template 50 will shrink more than the room temperature state by L4, and the mask metal film 110 will shrink accordingly. The process temperature TS3 may be about 5-15°C. In addition, the maintenance time of the process temperature TS3 may be at least greater than or equal to Figure 8The maintenance time of process temperatures TS1 and TS2 in (b) and (c) is determined. For example, if the maintenance time of TS1 is 10 minutes and the maintenance time of TS2 is 5 minutes, the maintenance time of TS3 can be more than 10 minutes. By the above-mentioned rapid cooling rather than slow cooling, the viscosity of the temporary bonding portion 55 increases, thereby further increasing the bonding strength. With the bonding strength of the temporary bonding portion 55 maximized, the mask metal film 110 and the template 50 can be further firmly bonded. Figure 8 The length of the mask metal film 110 further extended in step (b) can still be maintained after the temperature drops.

[0115] Figure 9 1 is a comparison data between the initial design dimensions of the mask and the dimensions after the process is completed according to an experimental example of the present invention. Figure 9 (a) and (c) show the initial state of the two samples, (b) and (d) show the execution Figure 8 The post-processing state. Three points were set at the top, middle, and bottom of the mask metal film 110 (or mask 100) and their sizes were compared. The dashed lines in (a) to (d) represent the design preset values, while the solid lines represent the actual measured values.

[0116] Comparing (a) with (b) and (c) with (d), we can see that when executing Figure 8 After the process, the dotted lines have a larger spacing than the solid lines. This indicates that the mask metal film 110 has extended compared to the same point. Comparing (a) and (b), it can be seen that it has further extended by approximately 1.6μm in the X-axis (short side) direction and approximately 4.3μm in the Y-axis (long side) direction. Comparing (c) and (d), it can be seen that it has further extended by approximately 0.9μm in the X-axis direction and approximately 3.3μm in the Y-axis direction.

[0117] Figure 10 FIG. 4 is a schematic diagram of a method for measuring the total pitch of a mask before and after a process according to an experimental example of the present invention.

[0118] The conditions in Table 1 were as follows. Figure 7 and Figure 8 technology.

[0119] Table 1

[0120]

[0121]

[0122] Experimental Examples 1 to 3 correspond to Figure 7 process, Experimental Examples 5, 6 and 8 correspond to Figure 8 In Experiment 4, only the initial rising temperature TS2 corresponds to Figure 8process, Experimental Example 7 corresponds to Figure 8 A process in which the step of descending to TS2 is omitted and the process is directly cooled to TS3.

[0123] Figure 10 This section describes a method for measuring the extended state of mask 100 after a process. The portion of mask 100 actually attached to frame 200 (mask unit sheet 220) and functioning as mask unit C is where the mask pattern P is formed. Therefore, the extended state can be measured using the position of mask pattern P, excluding the dummy portion DM, as a reference. The distance between mask patterns P at the ends of a mask unit C is called the total pitch (TP).

[0124] Reference Figure 10 When the mask 100 has a pair of long sides (X-axis sides) and a pair of short sides (Y-axis sides), if the mask 100 is equally divided into three regions along the short sides, arbitrary straight lines S1, S2, and S3 are extended in a direction perpendicular to the short sides in each region, and the average value (X-axis TP) of the distances from the mask pattern P arranged at one end to the mask pattern P arranged at the other end along the arbitrary straight lines S1, S2, and S3 can be calculated. Furthermore, if the mask 100 is equally divided into three regions along the long sides, arbitrary straight lines S4, S5, and S6 are extended in a direction perpendicular to the long sides in each region, and the average value (Y-axis TP) of the distances from the mask pattern P arranged at one end to the mask pattern P arranged at the other end along the arbitrary straight lines S4, S5, and S6 can be calculated.

[0125] The following table shows the X-axis (long axis) TP and Y-axis (short axis) TP of Experimental Examples 1-8. The average value of each axis can be calculated by measuring the TP of three areas. Figure 8 The TP value measured after the process is deducted from the execution Figure 7 The TP value is obtained by measuring the TP value after the process. Figure 8 The TP value measured after the process is deducted Figure 9 The preset design values ​​described in (refer to Figure 9 TP was measured for three samples in Experiments 1-7, and for two samples in Experiment 8. The adhesive strength of temporary adhesive section 55 in each experiment was approximately 40 kgf / cm² (-4 MPa). The values ​​in the table are in μm.

[0126] Table 2

[0127] Experimental example X-axis ΔTP Y-axis ΔTP X-axis ΔTP average / Y-axis ΔTP average Experimental Example 1 -0.9 / -0.6 / +0.2 -0.2 / -0.1 / +0.8 -0.4 / +0.2 Experimental Example 2 -0.6 / -0.7 / -0.2 +0.1 / -0.3 / +0.1 -0.5 / -0.0 Experimental Example 3 -0.1 / -0.3 / -0.6 0.0 / 0.0 / +0.2 -0.6 / +0.1 Experimental Example 4 +0.6 / +1.0 / +0.6 0.0 / +0.3 / -0.2 +0.7 / +0.0 Experimental Example 5 +1.1 / +0.9 / -0.4 +0.6 / +0.6 / +0.3 +0.5 / +0.5 Experimental Example 6 +2.6 / +5.5 / +3.8 +1.7 / +2.7 / +2.0 +4.0 / +2.1 Experimental Example 7 +2.0 / +2.3 / +2.0 +1.7 / +2.1 / +1.2 +2.1 / +1.7 Experimental Example 8 +6.8 / +5.2 +2.9 / +2.3 +6.0 / +2.6

[0128] Referring to Table 2, it can be seen that the average of ΔTP in Experimental Examples 1 to 3 is negative rather than positive. Figure 8The average of ΔTP is a positive number in Experimental Examples 5, 6, and 8. In particular, it was confirmed that the absolute value of ΔTP increases as Experimental Examples 5, 6, and 8 are performed, that is, as the initial temperature rise TP2 increases.

[0129] In particular, ΔTP is preferably approximately 0.1 μm to 20.0 μm based on the major axis, and approximately 0.1 μm to 15.0 μm based on the minor axis. If it is smaller than this, it will be difficult to maintain sufficient tension on the frame 200. If it is larger than this, the tension exerted by the mask 100 on the frame 200 will increase, increasing the likelihood of misalignment of the mask pattern P, which may in turn cause wrinkles in parts of the mask 100.

[0130] Figure 11 FIG. 5 is a schematic diagram illustrating a state in which the template 50 is loaded onto the frame 200 and the mask 100 is aligned with the unit region CR of the frame 200 according to an embodiment of the present invention. Figure 11 , a method of corresponding / attaching one mask 100 to the unit region CR is listed, but a process of simultaneously corresponding multiple masks 100 to all unit regions CR and attaching the masks 100 to the frame 200 can also be performed. In this case, there can be multiple templates 50, which are used to support each of the multiple masks 100 respectively.

[0131] The template 50 can be transferred using a vacuum suction cup 90. The vacuum suction cup 90 can be used to suck the opposite side of the template 50 to which the mask 100 is bonded and then transferred. After the vacuum suction cup 90 sucks the template 50 and flips it, the template 50 can be transferred to the frame 200 without affecting the bonding and alignment of the mask 100.

[0132] Then refer to Figure 11 , the mask 100 can be aligned with a mask unit region CR of the frame 200. By loading the template 50 onto the frame 200 (or the mask unit sheet portion 220), the mask 100 can be aligned with the mask unit region CR. While controlling the position of the template 50 / vacuum chuck 90, the mask 100 can be observed under a microscope to ensure that it is aligned with the mask unit region CR. Because the template 50 presses the mask 100, the mask 100 can be tightly attached to the frame 200.

[0133] In addition, a lower support body 70 may be further disposed below the frame 200. The lower support body 70 can press the reverse side of the mask unit region CR in contact with the mask 100. Simultaneously, since the lower support body 70 and the template 50 press the edge of the mask 100 and the frame 200 (or the mask unit sheet portion 220) in opposite directions, the alignment of the mask 100 can be maintained without being disturbed.

[0134] Next, laser L is irradiated to the mask 100 and the mask 100 is attached to the frame 200 by laser welding. The laser welding generates weld beads WB on the weld portion WP of the mask. The weld beads WB may have the same material as the mask 100 / frame 200 and be integrally connected to them.

[0135] Figure 12 FIG. 2 is a schematic diagram illustrating a process of separating the mask from the template after attaching the mask to the frame according to an embodiment of the present invention.

[0136] Reference Figure 12 After the mask 100 is attached to the frame 200, the mask 100 can be separated from the template 50 (debonding). The separation of the mask 100 from the template 50 can be performed by heating the temporary adhesive portion 55, chemically treating the temporary adhesive portion 55, applying ultrasonic waves, or applying ultraviolet rays. Since the mask 100 remains attached to the frame 200, only the template 50 can be lifted. As an example, if heat ET at a temperature higher than 85°C-100°C is applied, the viscosity of the temporary adhesive portion 55 decreases, and the bonding force between the mask 100 and the template 50 is weakened, thereby allowing the mask 100 and the template 50 to be separated. As another example, the mask 100 can be separated from the template 50 by immersing the temporary adhesive portion 55 in a chemical substance such as IPA, acetone, or ethanol to dissolve or remove the temporary adhesive portion 55. As another example, the bonding force between the mask 100 and the template 50 is weakened by applying ultrasonic waves, US, or ultraviolet rays, thereby allowing the mask 100 to be separated from the template 50.

[0137] When the template 50 is separated from the mask 100, the tensile force IT applied to the mask 100 is released and converted into a tension TS that tightens both sides of the mask 100. Thus, the mask 100 can be attached in a tightened state by applying the tension TS to the frame 200 (mask unit sheet portion 220).

[0138] Figure 13 FIG. 2 is a schematic diagram illustrating a state where the mask 100 is attached to the frame 200 according to an embodiment of the present invention. Figure 13 2 shows a state where all the masks 100 are attached to the unit region CR of the frame 200. Although the masks 100 may be attached one by one and then the templates 50 may be separated, all the masks 100 may be attached and then all the templates 50 may be separated.

[0139] Existing Figure 1While the conventional mask 10 comprises six cells C1-C6 and is therefore longer, the mask 100 of the present invention comprises a single cell C and is therefore shorter, resulting in less distortion in pixel position accuracy (PPA). Furthermore, since the present invention only requires alignment verification for one cell C of mask 100, it significantly shortens manufacturing time compared to conventional methods that require simultaneous alignment verification for multiple cells C (C1-C6).

[0140] If each mask 100 is attached to its corresponding mask cell region CR before the template 50 and mask 100 are separated, the multiple masks 100 exert tensions TS in opposite directions, which cancel each other out. Consequently, no deformation occurs on the mask cell sheet portion 220. For example, on the first grid sheet portion 223 between the mask 100 attached to the CR11 cell region and the mask 100 attached to the CR12 cell region, the tension TS acting to the right of the mask 100 attached to the CR11 cell region and the tension TS acting to the left of the mask 100 attached to the CR12 cell region cancel each other out. Consequently, deformation of the frame 200 (or mask cell sheet portion 220) due to tension TS is minimized, thereby minimizing alignment errors of the mask 100 (or mask pattern P).

[0141] Next, a process of manufacturing a mask metal film using a rolling process and an internal stress distribution of the mask metal film generated by the rolling process will be described.

[0142] Figure 14 FIG. 1 is a schematic diagram of a process of manufacturing the mask metal film 110 by using a rolling process according to an embodiment of the present invention.

[0143] Reference Figure 14 , prepare a rolled piece 120 made of materials such as invar, super invar, nickel (Ni), and nickel-cobalt (Ni-Co), and the first rolling process can be performed using the first roller R1. After the first rolling process, a rolled plate 130 having a thickness of approximately 100 μm can be formed. Next, a second rolling process can be performed using the second roller R2 to form a mask metal film 110 having a thickness of approximately 40 μm. During the first rolling, due to the large diameter of the roller R1, the reduction rate becomes larger, and plastic deformation may occur inside the material. Therefore, tensile residual stress is generated on the surface, and compressive residual stress is generated inside. In addition, during the second rolling, due to the small diameter of the roller R2, the reduction rate becomes smaller, and plastic deformation may occur on the surface inside the material. Therefore, compressive residual stress is generated on the surface, and tensile residual stress is generated inside.

[0144] Figure 15 Schematic diagram of an internal stress model of a mask metal film manufactured by a rolling process and a state where the mask metal film and a template are bonded according to an embodiment of the present invention.

[0145] The mask metal film manufactured using a rolling process may have different internal stresses in the tensile direction X and in the width direction Y. Specifically, the compressive stress distribution and the tensile stress distribution may be different based on the tensile direction X, the width direction Y, the thickness direction, etc. In addition, the stress distribution in the tensile direction is wider than the stress distribution in the width direction. In addition, the internal stress above the mask metal film 110 and the internal stress below may be almost symmetrical. In addition, when the mask metal film is in a bonded state with the template, the stress distribution applied to the template will also be different based on this compressive stress / tensile stress, so this needs to be taken into account when manufacturing a frame-integrated mask.

[0146] Figure 16 Figure 1 is a schematic diagram illustrating the variation in the total pitch (TP) of a mask according to one embodiment of the present invention. The TP in the X and Y directions for each step is shown. As described above, the distance between the mask patterns P at the ends of a mask cell C is referred to as the total pitch (TP).

[0147] The figure shows the state after the mask metal film 110 and the template 50 are bonded (A. Bonded state), and the state after the mask pattern P is formed on the mask metal film 110 and the thickness reduction process (thinning; PS) is performed (B. After the unit process). Figure 8 The state ② is changed before the mask 100 is welded to the frame 200 by controlling the temperature (C. Before welding attachment). The initial free state illustrates the state in which the mask metal film 110 is manufactured by rolling without additional processes.

[0148] Compared to the attached state after the unit process, the TP in the X and Y directions is reduced. In addition, by controlling the temperature of the mask 100 / template 50 before welding the mask 100 to the frame 200, the TP is increased. In addition, if the template 50 is separated after welding the mask 100 to the frame 200, the TP is reduced.

[0149] The difference between TPx and TPy confirms that the degree of bending of template 50 in the x-axis due to the internal stress of mask metal film 110 is greater. Furthermore, it can be confirmed that controlling the temperature of mask 100 / template 50 results in greater stretching in the y-direction, where the tension is relatively small. Compared to the initial free state, the stretch increments in the x- and y-axes are almost the same.

[0150] Figure 17 Schematic diagram of the TP change before and after the mask 100 is welded to the frame 200 according to an embodiment of the present invention

[0151] Figure 17 "D. After welding attachment and template separation" in FIG. 1 shows a state in which the process from welding the mask 100 to the frame 200 to separating the template 50 from the mask 100 is performed. Figure 13 State]. It was confirmed that when the template 50 was separated from the mask 100 after welding, the mask 100 contracted more in the y direction than in the x direction where the warping was greater.

[0152] Figure 18 FIG. 1 is a schematic diagram of the stretching amount of each step based on a stable state after the mask 100 is welded to the frame 200 according to an embodiment of the present invention.

[0153] Compared to the free state, the total stretch of each mask cell C before welding is approximately 6 to 7 μm. In comparison, the stretch of a strip mask with multiple mask cells C is even greater, approximately 30 to 35 μm. Moreover, after the mask cell C formation process, the tensile force generated in the mask metal film 110 based on the natural tensile force (after the cell formation process - free state) is naturally generated due to rolling stress.

[0154] The TP variation according to one embodiment is shown in the table below: The unit of variation per side is μm.

[0155] Table 3

[0156]

[0157] Figure 19 FIG. 1 is a schematic diagram of a method for using a mask metal film 110 to match a tensile force according to an embodiment of the present invention.

[0158] like Figures 15 to 18 As described above, the amount of change in TP can vary depending on the tensile force and direction of the rolled Invar alloy (or the mask metal film 110). Therefore, the present invention can achieve a thinning of the mask metal film 110 by taking into account the internal stress distribution in the thickness direction of the rolled Invar alloy (or the mask metal film 110) when manufacturing a frame-integrated mask.

[0159] Specifically, a mask metal film 110 with controllable tensile force can be used. The tensile force of the mask metal film 110 is controlled by determining the internal stress distribution in the thickness direction of the mask metal film 110 manufactured by a rolling process; and reducing the thickness of at least one side of the mask metal film 110 in accordance with the internal stress distribution in the thickness direction. Furthermore, the mask 100 with controllable tensile force can be used by forming a plurality of mask patterns P on the mask metal film 110.

[0160] The mask metal film 110 manufactured by the rolling process can be reduced by any of the following methods (1) to (3): (1) reducing the mask metal film 110 to a predetermined thickness from the upper surface; (2) reducing the mask metal film 110 to a predetermined thickness from the lower surface; (3) reducing the mask metal film to a predetermined thickness from both the upper surface and the lower surface. Any of the mask metal films 110 in (1) to (3) can be used as the mask material. In the case of (3), the thickness reduced from the upper surface and the thickness reduced from the lower surface can be different.

[0161] As an example, you can use Figure 19 In Example ①, the mask metal film 110 is reduced from the lower surface to a predetermined thickness and includes the upper portion. Alternatively, a mask metal film 110 can be used that is reduced from both the upper and lower surfaces to the same thickness and includes the central portion, as in Example ②. Furthermore, a mask metal film 110 that is reduced more from the upper surface and less from the lower surface and includes the central portion, as in Example ③, can be used. Therefore, the stress distributions of the mask metal films 110 in Examples ① to ③ are different. In view of this, when manufacturing a frame-integrated mask, the desired mask metal film 110 can be applied by finding an appropriate tensile force. Consequently, the influence of the internal stress of the mask metal film on TP variations can be minimized during the manufacturing process of the frame-integrated mask.

[0162] Figure 20 FIG. 1 is a schematic diagram of a process of reducing the thickness of at least one side of a mask metal film based on the internal stress distribution of the mask metal film according to an embodiment of the present invention. Figure 19 The method (3) for reducing the thickness of the mold metal film 110 is described in the following. However, it is not limited to this. When reducing the preset thickness from the upper surface or the lower surface, it is possible to use Figure 20 The thickness reduction process is performed by performing some steps of the process.

[0163] Reference Figure 20 (a), the lower surface 112″ [second surface] of the mask metal film 110″ manufactured by the rolling process can be bonded to the supporting substrate 40 using the bonding portion 41. The bonding portion 41 can be made of the same material as the temporary bonding portion 55 or a material with a preset bonding force and can be separated, as long as this condition is met.

[0164] After the mask metal film 110″ is bonded to the supporting substrate 40, the upper surface 111″ [first surface] can be patterned PS1. Here, patterning PS1 and PS2 refers to mirroring one side of the mask metal film 110″ while removing a portion of the mask metal film 110″ to reduce the thickness and make it thinner. Patterning PS1 and PS2 can be performed using methods such as CMP, chemical wet etching, and dry etching.

[0165] Based on the thickness of the mask metal film 110″, assuming that the upper surface is 0% and the lower surface is 100%, the central portion 115″ can use at least a portion of the thickness portion of 10% to 90%. Assuming that planarization PS1 and PS2 are performed within approximately the same thickness range, the thickness reduction based on the planarization PS1 process performed from the upper surface 111″ can be performed between approximately 5% and 45% of the thickness of the entire mask metal film 110″. However, it is not necessarily limited to this. If the central portion 115″ uses at least a portion of the thickness portion of 10% to 90% based on the thickness of the mask metal film 110″, the degree of thickness reduction in each planarization PS1 and PS2 process can be variable.

[0166] After the planarization PS1 process, the upper portion 117 ″ of the mask metal film 110 ″ may be removed.

[0167] Then, refer to Figure 20 (b), another supporting substrate 45 may be prepared, and the upper surface 111″ [first surface] of the mask metal film 110′ may be bonded to the supporting substrate 45 using the bonding portion 46. The supporting substrate 45 and the bonding portion 46 may be the same as the supporting substrate 40 and the bonding portion 41. Alternatively, the supporting substrate 45 may correspond to the template 50, and the bonding portion 46 may correspond to the temporary bonding portion 55. In this case, Figure 5 Step (b) can also be performed by Figure 20 The method is replaced by step (b).

[0168] Then, refer to Figure 20 (c), after the mask metal film 110' is bonded to the support substrate 45, the support substrate 40 may be separated. Next, the second surface 112" may be planarized PS2. After the planarization PS2 process, the lower layer 119" of the mask metal film 110" may be removed.

[0169] Then, refer to Figure 20 In step (d), if the planarization PS2 is completed, the manufacturing of the mask metal film 110 may be completed. The mask metal film 110 may include a central portion 115 ″, and the thickness of the mask metal film 110 may be approximately 5 μm to 20 μm.

[0170] Figure 21FIG. 1 is a schematic diagram of the internal stress distribution state in the tensile direction and the width direction of the mask metal film manufactured by the rolling process according to one embodiment of the present invention.

[0171] like Figure 15 As described in , the mask metal film manufactured by the rolling process has different internal stresses in the tensile direction X and the width direction Y. Figure 21 Taking a mask metal film 110 with a thickness of approximately 40 μm as an example, the mask metal film 110 includes a compressive stress region and a tensile stress region based on the thickness direction. Specifically, with respect to the tensile direction X, the mask metal film 110 includes compressive stress regions at its upper and lower portions, and a tensile stress region in its middle portion, based on the thickness direction. Furthermore, with respect to the width direction Y, the side portions of the mask metal film 110 include a compressive stress region, while the middle portion includes a tensile stress region.

[0172] Figure 22 FIG. 1 is a schematic diagram of a sample of a mask 100 based on internal stress distribution according to an embodiment of the present invention.

[0173] Reference Figure 22 Samples (a) through (e) were fabricated using a 40μm-thick mask metal film 110, each having different portions along the thickness direction. The 40μm-thick mask metal film 110 was subjected to a thickness reduction process on at least one side (the upper and lower surfaces) to a thickness of 15μm, and then used as samples (a) through (e). The diagram shows the shape of a mask pattern P after two etching processes were performed on the upper and lower surfaces of each sample (a) through (e).

[0174] Sample (a) is a case where the thickness is reduced only from the upper surface but not from the lower surface, sample (b) is a case where the thickness is reduced by approximately 4 μm from the lower surface and by approximately 21 μm from the upper surface, sample (c) is a case where the thickness is reduced by approximately 8 μm from the lower surface and by approximately 17 μm from the upper surface, sample (d) is a case where the thickness is reduced by approximately 1 μm from the lower surface and by approximately 13 μm from the upper surface, and sample (e) is a case where the thickness is reduced by approximately 15 μm from the lower surface and by approximately 10 μm from the upper surface.

[0175] From another perspective, sample (a) includes a relatively large portion of the lower portion of the mask metal film 110 and therefore includes more compressive stress intervals. Furthermore, as the sample approaches sample (e), the middle portion of the mask metal film 110 is included more while the lower portion is removed, and therefore includes more tensile stress intervals.

[0176] Figure 23 yes Figure 22 Comparative data of the size of the mask (100) of the sample in the initial design and the size after the process. Figure 23(a) to (e) are respectively Figure 22 The dotted lines in (a) to (e) are the design preset values, and the solid lines are the actual measured values.

[0177] Reference Figure 23 From (a) to (e), it can be confirmed that the closer from (a) to (e), the solid line portion gradually shifts inward toward the dotted line portion. Sample (a) extends approximately 13.3μm in the X-axis (short side) direction and approximately 4.7μm in the Y-axis (long side) direction compared to the design preset value. Sample (b) extends approximately 5.6μm in the X-axis (short side) direction and approximately 3.1μm in the Y-axis (long side) direction compared to the design preset value. Sample (c) extends approximately 3.2μm in the X-axis (short side) direction and approximately 6.5μm in the Y-axis (long side) direction compared to the design preset value. Sample (d) extends approximately 6.3μm in the X-axis (short side) direction and approximately 2.9μm in the Y-axis (long side) direction compared to the design preset value. Compared with the design preset value, the sample (e) is extended by about 12.5 μm in the X-axis (short side) direction and about 8.0 μm in the Y-axis (long side) direction.

[0178] Sample (c) is closest to the design preset value because sample (c) uses the central portion of the mask metal film 110 where the grains are most uniform.

[0179] Observation based on the X-axis (short side) confirmed that the mask 100 adhered to the template 50 in a state of being further extended than the initial design value as the sample (a) approaches the sample (e).

[0180] Furthermore, it can be confirmed that the closer the sample (a) is to the sample (e), that is, the more tensile stress intervals the mask 100 includes compared to the compressive stress intervals, the smaller the degree of stretching in the lateral direction of the mask 100 becomes. This stretching is induced by the residual stress inside the mask 100 generated during the rolling process, rather than being directly applied to the mask 100 from the outside. From another point of view, the greater the ratio of the compressive stress interval to the tensile stress interval in the mask 100, the greater the tensile force in the lateral direction of the mask 100. The mask 100 is in a state of being bonded to the template 50, and Figure 8 Unlike the change in the tensile force based on the process temperature change described in , the tensile force can further change based on the residual stress of the mask 100 itself.

[0181] Therefore, by determining the internal stress distribution in the thickness direction of the mask metal film 110 manufactured by the rolling process, only a portion of the mask metal film 110 corresponding to the tensile force to be used is taken out and bonded to the template 50, and by applying Figure 8The process temperature changes can ultimately control the tensile force IT of the mask 100 on the template 50.

[0182] Figure 24 yes Figure 22 A graph showing the required stretching of the mask side based on the internal stress distribution of the sample. Figure 23 (a) to (e) and Figure 22 and Figure 23 Corresponding to samples (a) to (e).

[0183] Reference Figure 24 (a) to (e) illustrate the required stretching amount of the mask 100 required when manufacturing a frame-integrated mask. Figure 23 As shown in Figure 3, sample (a) exhibits a relatively large degree of lateral stretch compared to the design preset value. As the mask approaches sample (e), the degree of lateral stretch decreases compared to the design preset value. Therefore, the required lateral stretching of mask 100 in sample (a) is as small as almost zero, while the required stretching increases to approximately 13 μm as the mask approaches sample (e).

[0184] As described above, the present invention can control the ratio of the compressive stress region to the tensile stress region within the reduced-thickness mask metal film 110, thereby controlling the tensile force that needs to be applied while the mask 100 is bonded to the template 50. Furthermore, depending on the specific portion of the mask 100, direct tensile force need not be applied; simply utilizing the residual stress within the mask 100 can ensure the tensile force required to maintain tight adhesion to the frame 200. Furthermore, after the mask 100 is welded to the frame 200, the tension exerted on the frame 200 by the mask 100 can be controlled as the template 50 is separated from the mask 100.

[0185] As described above, the present invention has been illustrated and described with reference to preferred embodiments. However, the present invention is not limited to the above embodiments. Various modifications and variations can be made by those skilled in the art without departing from the spirit of the present invention. Such modifications and variations are intended to fall within the scope of the present invention and the appended claims.

[0186] [Description of Reference Numerals]

[0187] 23: First insulation part

[0188] 25: Second insulating part

[0189] 50: template

[0190] 51: Laser through hole

[0191] 55: Temporary bonding part

[0192] 100: Mask

[0193] 110: Mask film, mask metal film

[0194] 200: Framework

[0195] 210: Edge frame

[0196] 220: Mask unit sheet portion

[0197] 221: Edge sheet part

[0198] 223: First grid sheet portion

[0199] 225: Second grid sheet portion

[0200] C: unit, mask unit

[0201] CR: Mask cell region

[0202] DM: dummy part, mask dummy part

[0203] L: Laser

[0204] P: mask pattern

[0205] RT: room temperature

[0206] TS1, TS2, TS3: first, second, third process temperature

[0207] WB: Weld Bead

Claims

1. A method for controlling the tensile force of a mask, wherein the method is used to control the tensile force of the mask during the manufacturing process of a frame-integrated mask in which a frame and a plurality of masks are connected, comprising the following steps: (a) determining the internal stress distribution in the thickness direction of a mask metal film manufactured by a rolling process, wherein the upper and lower portions of the mask metal film, based on the thickness direction, include compressive stress regions, and the middle portion includes a tensile stress region; (b) reducing a predetermined thickness from the upper and lower surfaces of the mask metal film according to the internal stress distribution in the thickness direction; (c) A mask is prepared by forming a plurality of mask patterns on the mask metal film.

2. The method for controlling the tensile force of a mask according to claim 1, wherein: In the step (b), the thicknesses reduced from the upper surface and the lower surface are different from each other.

3. The method for controlling the tensile force of a mask according to claim 1, wherein: In the step (c), a plurality of mask patterns are formed in a state where the mask metal film is bonded to the template with a temporary bonding portion interposed therebetween.

4. The method for controlling the tensile force of a mask according to claim 1, wherein: In the step (b), the greater the ratio of the compressive stress interval to the tensile stress interval in the reduced-thickness mask metal film, the greater the tensile force on the template toward the side surface of the mask.

5. The method for controlling the tensile force of a mask according to claim 1, wherein: In the step (b), in the mask metal film with reduced thickness, if the ratio of the compressive stress interval is greater than the ratio of the tensile stress interval, then after the step (c), the mask appears to be bonded to the template in a state of further extending toward at least one side compared to the initial design value.

6. The method for controlling the tensile force of a mask according to claim 1, wherein: In the step (b), in the mask metal film with reduced thickness, if the ratio of the tensile stress interval is greater than the ratio of the compressive stress interval, then after the step (c), the mask is bonded to the template in a state of being further shrunk toward at least one side compared to the initial design value.

7. A method for manufacturing a frame-integrated mask, wherein the frame-integrated mask is formed by integrating an OLED pixel forming mask and a frame, comprising the following steps: (a) determining the internal stress distribution in the thickness direction of a mask metal film manufactured by a rolling process, wherein the upper and lower portions of the mask metal film, based on the thickness direction, include compressive stress regions, and the middle portion includes a tensile stress region; (b) bonding the mask metal film to a template with a temporary bonding portion interposed therebetween; (c) reducing a predetermined thickness from the upper and lower surfaces of the mask metal film according to the internal stress distribution in the thickness direction; (d) preparing a mask by forming a plurality of mask patterns on the mask metal film; (e) Attach the mask to the frame.

8. The method for manufacturing a frame-integrated mask according to claim 7, wherein: Further comprising the step of (f) separating the template from the mask.

9. The method for manufacturing a frame-integrated mask according to claim 8, wherein: In the step (b), the greater the ratio of the compressive stress interval to the tensile stress interval in the reduced-thickness mask metal film, the greater the tensile force on the template toward the side surface of the mask.

10. The method for manufacturing a frame-integrated mask according to claim 9, wherein: In the step (b), the tension applied by the mask to the frame after the step (f) is controlled by controlling the ratio of the compressive stress region to the tensile stress region in the mask metal film with reduced thickness.

Images