Method for manufacturing a deposition mask

Abstract

To provide a method for manufacturing a vapor deposition mask that is improved in location accuracy of an opening region.SOLUTION: A method for manufacturing a vapor deposition mask includes the steps of: forming a photoresist layer, in which a predetermined pattern is formed, on a support substrate via a base metal layer; disposing the support substrate so as to position a first surface of the support substrate perpendicular to a horizontal plane and measuring a first warpage of the support substrate; forming a mask body by precipitating a metal by electroforming in a region where the photoresist layer is not formed in the base metal layer; disposing the support substrate so as to position the first surface of the support substrate perpendicular to a horizontal plane and measuring a second warpage of the support substrate; and calculating a shrinkage rate of the mask body on the basis of a change amount of warpage calculated on the basis of the first warpage and the second warpage as well as internal stress of the support substrate calculated on the basis of the change amount of warpage.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a deposition mask, and more particularly to a method for manufacturing a deposition mask having a thin-film mask body attached to a mask frame.

[0002] Examples of flat panel display devices include liquid crystal display devices and organic electroluminescence (EL) display devices. These display devices are structures in which thin films containing various materials such as insulators, semiconductors, and conductors are stacked on a substrate. These thin films are appropriately patterned and connected to realize the display device's function.

[0003] Methods for forming thin films can be broadly classified into gas-phase methods, liquid-phase methods, and solid-phase methods. Gas-phase methods are further classified into physical vapor methods and chemical vapor methods. Vapor deposition is a well-known example of a physical vapor method. The simplest vapor deposition method is vacuum deposition. In vacuum deposition, a material is heated under high vacuum to sublimate or evaporate the material, generating vapor (hereinafter, these methods are collectively referred to as vaporization). In the region for depositing this material (hereinafter, deposition region), the vaporized material solidifies and is deposited, resulting in a thin film of the material. Vacuum deposition is performed using a mask (deposition mask) to selectively form a thin film in the deposition region and prevent the material from being deposited in other regions (hereinafter, non-deposition region) (see Patent Documents 1 and 2).

[0004] The deposition mask has a mask frame attached to a mask body on which a deposition pattern is formed, and the mask body is formed by forming a plating film using a photoresist layer having a predetermined pattern formed on a support substrate via a metal layer as a mask, attaching the frame, and then separating the mask body from the support substrate and the underlying metal layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-87840 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-209710 Summary of the Invention [Problem to be solved by the invention]

[0006] During the mask body manufacturing process, when a plating layer consisting of a fine pattern formed on a support substrate by electroplating is separated from the support substrate, the plating layer shrinks due to stress in the plating layer. This causes the opening area to shift from the desired position, making it important to manage the shrinkage rate of the plating layer. However, since the shrinkage rate of the plating layer cannot be measured unless the plating layer is separated from the support substrate, it takes a certain number of days to feed back the measured shrinkage rate to the fine pattern formation process and the plating layer formation process.

[0007] On the other hand, there is a method for measuring the shrinkage of a plating layer by forming the plating layer on a dummy support substrate and immediately peeling it off. In this method, the plating layer needs to be formed thick enough so that it will not be damaged or deformed even if it is peeled off alone. However, the plating layer peeled off from the dummy support substrate is in a different state from the plating layer that constitutes the actual mask body, making it difficult to accurately evaluate the shrinkage.

[0008] In view of the above problems, an object of one embodiment of the present invention is to provide a method for manufacturing a deposition mask with improved positional accuracy of opening regions. [Means for solving the problem]

[0009] A method for manufacturing a vapor deposition mask according to one embodiment of the present invention includes forming a photoresist layer having a predetermined pattern on a support substrate via a metal base layer, positioning the support substrate so that a first surface of the support substrate is perpendicular to a horizontal plane, measuring a first amount of warpage of the support substrate, forming a mask body by electroforming metal in an area of ​​the metal base layer where the photoresist layer is not formed, positioning the support substrate so that the first surface of the support substrate is perpendicular to the horizontal plane, measuring a second amount of warpage of the support substrate, calculating a shrinkage rate of the mask body based on an amount of change in the amount of warpage calculated based on the first and second amounts of warpage and an internal stress of the support substrate calculated based on the amount of change in the amount of warpage, and changing the drawing coordinates of each of the predetermined patterns on a mask body to be manufactured next according to the shrinkage rate of the mask body when the shrinkage rate of the mask body is smaller than the lower limit of a predetermined range and is equal to or greater than a first threshold, or when the shrinkage rate of the mask body is greater than the upper limit of the predetermined range and is equal to or less than a second threshold. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1 is a plan view of a deposition mask according to an embodiment of the present invention. [Figure 1B] FIG. 1 is a plan view of a deposition mask according to an embodiment of the present invention. [Figure 1C] 1 is a cross-sectional view of a deposition mask according to one embodiment of the present invention. [Figure 2] 1 is a flowchart illustrating an outline of a manufacturing process of a deposition mask according to an embodiment of the present invention. [Figure 3] 10 is a flowchart illustrating a process for adjusting the shrinkage rate of the mask body. [Figure 4A] 5A to 5C are cross-sectional views showing a method for manufacturing the mask body. [Figure 4B] 5A to 5C are cross-sectional views showing a method for manufacturing the mask body. [Figure 4C] 5A to 5C are cross-sectional views showing a method for manufacturing the mask body. [Figure 5] This shows the results of a simulation of the amount of warpage when a plating layer is formed on a SUS substrate. [Figure 6]10 shows the results of a simulation of the amount of warpage when a plating layer is formed on a glass substrate. [Figure 7] 6 is a diagram showing regions 301 to 305 shown in FIG. 5 schematically represented on a support substrate. [Figure 8] 6 is an example of a photoresist layer after adjusting the magnification of a predetermined pattern based on the shrinkage rate of the mask body obtained from FIG. 5. [Figure 9A] 5A to 5C are cross-sectional views showing a method of forming a mask frame on a mask body. [Figure 9B] 5A to 5C are cross-sectional views showing a method of forming a mask frame on a mask body. [Figure 9C] 5A to 5C are cross-sectional views showing a method of forming a mask frame on a mask body. [Figure 9D] 5A to 5C are cross-sectional views showing a method of forming a mask frame on a mask body. [Figure 9E] 5A to 5C are cross-sectional views showing a method of forming a mask frame on a mask body. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, each embodiment of the present invention will be described with reference to the drawings, etc. However, the present invention can be embodied in various forms without departing from the spirit of the present invention, and should not be construed as being limited to the description of the embodiments exemplified below.

[0012] In order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part more schematically than the actual embodiment. However, the examples shown in the drawings are merely examples and do not limit the interpretation of the present invention unless otherwise specified. In this specification and each drawing, the same components as those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0013] In this specification and claims, when expressing an aspect in which another structure is placed on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both a case in which another structure is placed directly on top of the structure so as to be in contact with the structure, and a case in which another structure is placed above the structure via yet another structure.

[0014] (First embodiment) The configuration of a deposition mask according to one embodiment of the present invention will be described with reference to FIGS. 1A to 1C.

[0015] 1A and 1B are plan views of a deposition mask 10 according to one embodiment of the present invention. Specifically, FIG. 1A is a plan view of the deposition mask 10 as viewed from a first surface 110a of a mask body 110, and FIG. 1B is a plan view of the deposition mask 10 as viewed from a second surface 110b opposite to the first surface 110a of the mask body 110. FIG. 1C is a cross-sectional view of the deposition mask 10 according to one embodiment of the present invention. Specifically, FIG. 1C is a cross-sectional view of the deposition mask 10 taken along line A1-A2 shown in FIG. 1A or 1B.

[0016] The deposition mask 10 includes a mask body 110, a mask frame 120, and a connecting portion 130. The mask body 110 has a first surface 110a and a second surface 110b. As shown in FIGS. 1A and 1B, the mask frame 120 and the connecting portion 130 are provided on the first surface 110a of the mask body 110. In addition, in a plan view, the mask frame 120 and the connecting portion 130 overlap with the mask body 110. As shown in FIG. 1A, in a plan view seen from the first surface 110a of the mask body 110, the mask frame 120 and the connecting portion 130 are exposed from the mask body 110. On the other hand, as shown in FIG. 1B, in a plan view seen from the second surface 110b of the mask body 110, the mask frame 120 and the connecting portion 130 are not exposed from the mask body 110. In other words, in a plan view seen from the second surface 110b of the mask body 110, the mask frame 120 and the connection portion 130 are covered by the mask body 110.

[0017] The mask body 110 includes an opening region 111 and a non-opening region 112. The opening region 111 has openings 113 that penetrate the mask body 110 and correspond to the deposition pattern. On the other hand, the non-opening region 112 has no openings 113. The boundary between the opening region 111 and the non-opening region 112 is not always clear. However, in many cases, the openings 113 are provided according to the deposition pattern, and therefore the interval between two adjacent openings 113 has a predetermined pitch. Therefore, it is possible to distinguish the opening region 111 from the non-opening region 112 based on the predetermined pitch of the deposition pattern.

[0018] The thickness of the mask body 110 is, for example, 1 μm or more and 10 μm or less. The mask body 110 is preferably formed from a material used in electroforming (or electrolytic plating). The mask body 110 is formed by electroforming from a material such as nickel or a nickel alloy.

[0019] When a deposition process is performed using the deposition mask 10, a substrate to be deposited is provided on the second surface 110b of the mask body 110. For example, a circuit board having transistors and the like formed thereon is used as the substrate to be deposited. The deposition mask 10 is fixed in a chamber of the deposition device with the substrate to be deposited sandwiched between the deposition mask 10 and the deposition mask 10, while being attracted by magnets provided in the deposition device. In the deposition device, a deposition source is provided on the first surface 110a side of the mask body 110. The deposition source is heated, causing the organic material to be heated and sublimated or evaporated. In this deposition process, the organic material is deposited by passing only through the openings 113 in the mask body 110. Therefore, a pattern (deposition pattern) corresponding to the openings 113 is formed on the substrate to be deposited. The openings 113 can be provided, for example, to correspond to the pixel arrangement of a display device and can be arranged in a matrix. The openings 113 are arranged in an x-axis direction (also referred to as a first direction) and a y-axis direction (also referred to as a second direction). In Figure 1A, if the center of the mask body 110 is taken as the reference point and the reference point is taken as coordinate O(0,0), the four corners of the substrate are coordinates A(-x,y), coordinate B(-x,-y), coordinate C(x,-y), and coordinate D(x,-y).

[0020] The mask frame 120 includes a frame portion 121 located on the outer periphery of the deposition mask 10 and crosspieces 122 located inside the frame portion 121. The mask frame 120 has an opening on the inside of the frame portion 121, and the opening is partitioned by the crosspieces 122 arranged in a grid pattern. When the size of the mask frame 120 increases, it may be difficult to maintain the parallelism of the mask frame 120 at a predetermined standard due to warping or twisting of the frame portion 121. In the deposition mask 10, the crosspieces 122 increase the rigidity of the frame portion 121, thereby enabling the parallelism of the mask frame 120 to be maintained at a predetermined standard. Note that when the size of the deposition mask 10 is small and the rigidity of the frame portion 121 is sufficiently high, the crosspieces 122 may not be provided.

[0021] The mask frame 120 may be formed by integrating the frame portion 121 and the crosspiece portion 122, or may be formed by separately manufacturing the frame portion 121 and the crosspiece portion 122 and welding them together.

[0022] In FIG. 1A, the mask frame 120 is divided into 12 openings by the crosspieces 122, but the number of divided openings is not limited to this. The number of divided openings can be determined appropriately depending on the size of the substrate to be vapor-deposited and the vapor deposition pattern. Furthermore, the arrangement of the crosspieces 122 is not limited to a lattice pattern. When the mask frame 120 is rectangular with short and long sides, warping or twisting is more likely to occur on the long sides than on the short sides. Therefore, it is preferable that the crosspieces 122 are provided so as to connect the opposing long sides. Furthermore, the arrangement of the crosspieces 122 may be shaped according to the vapor deposition pattern.

[0023] The width of the frame portion 121 and the width of the crosspiece 122 can be determined appropriately according to the size of the deposition mask 10. Note that, in order to make the region of the deposition pattern as large as possible, it is preferable that the width of the crosspiece 122 be smaller than the width of the frame portion 121.

[0024] The thickness of the mask frame 120 is, for example, 10 μm or more and 2000 μm or less. The mask frame 120 is preferably made of a material with a low thermal expansion coefficient. For example, the mask frame 120 can be made of a material such as Invar, which contains iron and nickel, or Super Invar, which contains iron, nickel, and cobalt.

[0025] The connecting portion 130 can connect the mask body 110 and the mask frame 120. As shown in Fig. 1C, the mask body 110 and the mask frame 120 are in direct contact with each other, but are not adhered or joined to each other. By joining the connecting portion 130 to the mask body 110 and the mask frame 120, the mask body 110 and the mask frame 120 are connected and fixed via the connecting portion 130.

[0026] The connecting portions 130 may be provided on at least a portion of the side surface of the frame portion 121 or the crosspiece 122 of the mask frame 120. However, in order to increase the bonding strength between the mask body 110 and the mask frame 120, the connecting portions 130 are preferably provided on at least half of the side surface of the frame portion 121 or the crosspiece 122, and more preferably on the entire side surface of the frame portion 121 or the crosspiece 122. The connecting portions 130 are preferably formed from a material used in electroforming. The connecting portions 130 are formed from a material such as nickel or a nickel alloy, for example. The material of the connecting portions 130 may be the same as or different from the material of the mask body 110.

[0027] As described above, in the deposition mask 10, the mask body 110 and the mask frame 120 are in direct contact with each other, but are not directly fixed to each other. Therefore, even if the mask body 110 and the mask frame 120 are made of materials with different thermal expansion coefficients, stress in the mask body 110 or the mask frame 120 can be dispersed. Note that the mask body 110 and the mask frame 120 may not be in direct contact with each other, and a gap may be provided between the mask body 110 and the mask frame 120. In this case, stress in the mask body 110 or the mask frame 120 can also be dispersed.

[0028] During the mask body manufacturing process, when the plating layer, which is made up of a fine pattern formed by electroplating, is separated from the plating support substrate, the plating layer shrinks due to stress in the plating layer. This causes the opening area to shift from the desired position, making it important to manage the shrinkage rate of the plating layer. However, since the shrinkage rate of the plating layer cannot be measured unless the plating layer is separated from the support substrate, it takes several days to feed back the measured shrinkage rate to the fine pattern formation process and the plating layer formation process.

[0029] On the other hand, there is a method for measuring the shrinkage of a plating layer by forming the plating layer on a dummy support substrate, immediately peeling it off, and then measuring the shrinkage of the plating layer. In this method, the plating layer needs to be formed thick enough so that it will not be damaged or deformed even if it is peeled off alone. However, the plating layer peeled off from the dummy support substrate is in a different state from the plating layer that constitutes the actual mask body, making it difficult to accurately evaluate the shrinkage.

[0030] In view of the above problems, an object of one embodiment of the present invention is to provide a method for manufacturing a deposition mask with improved positional accuracy of opening regions.

[0031] In one embodiment of the present invention, an in-line inspection of the shrinkage rate of the mask body is performed during the deposition mask manufacturing process, and the inspection results are fed back to the previous process. This allows the shrinkage rate of the mask body to be inspected at the stage where the mask body is formed, before the deposition mask is completed, and the inspection results can be fed back earlier. Furthermore, the number of deposition masks manufactured that have a large shrinkage rate and low positional accuracy of the opening region can be reduced. In other words, the yield of usable deposition masks can be improved.

[0032] Hereinafter, a method for manufacturing a deposition mask according to one embodiment of the present invention will be described with reference to FIGS. 2 to 9E.

[0033] FIG. 2 is a flowchart outlining a method for manufacturing a deposition mask. In this embodiment, the deposition mask 10 is manufactured as follows. First, when the manufacturing process of the deposition mask 10 is started, it is determined whether or not a termination condition for the manufacturing process is satisfied (step S401). If the termination condition is satisfied (step S401; Yes), the process proceeds. If the termination condition is not satisfied (step S401; No), the process proceeds to a step of adjusting the shrinkage rate of the mask body (step S402). Next, it is determined whether or not a termination condition for the loop is satisfied (step S403). If the termination condition for the loop is not satisfied (step S403; No), the process proceeds to a step of forming the mask body (step S404) and a step of forming the mask frame (step S405), and then the process returns to step S403, and the loop process is repeatedly executed. If the termination condition for the loop is satisfied (step S403; Yes), the process returns to step S401. In the following description, the deposition masks 10 will be referred to as deposition masks 10-1, 10-2, and 10-3 in the order in which they are manufactured, and will be referred to as deposition masks 10 when there is no need to distinguish between the manufacturing order. The same applies to the components of the deposition mask 10. Each of the steps S401 to S405 will be described in detail below.

[0034] The termination condition in step S401 is, for example, whether a predetermined number of deposition masks 10 have been manufactured or whether an operation for terminating the manufacture of deposition masks has been performed. Here, a case where the first deposition mask 10-1 is manufactured will be described, and therefore, if the termination condition is not satisfied (step S401; No), the process proceeds to step S402.

[0035] The process of adjusting the shrinkage rate of the mask body in step S402 will be described with reference to FIG. 3 and FIGS. 4A to 4C.

[0036] FIG. 3 is a flowchart illustrating a process for adjusting the shrinkage rate of the mask body 110. First, a photoresist layer 230 having a predetermined pattern is formed on a support substrate 210 on which an Nth mask body is to be formed (step S411 shown in FIG. 3). Here, the description is given assuming that N=1. The predetermined pattern is an opening pattern formed in the mask body. FIG. 4A illustrates a process for forming a metal layer 220 on the support substrate 210 and then forming a photoresist layer 230 having a predetermined pattern on the metal layer 220. The support substrate 210 has a first surface 210a and a second surface 210b. The metal layer 220 is formed on the first surface 210a side. In a plan view, the shape of the pattern of the photoresist layer 230 is, for example, approximately rectangular. In this case, the pattern arrangement corresponds to the pixel arrangement of the display device and is arranged in a matrix. When manufacturing the first deposition mask 10-1, the pattern arrangement may be a pattern designed to be unaffected by the shrinkage of the mask body, or may be a pattern designed from the beginning taking the influence of the shrinkage of the mask body into consideration.

[0037] The support substrate 210 supports each layer in the manufacturing process of the deposition mask 10. Therefore, the support substrate 210 is preferably a rigid substrate. The manufacturing process of the deposition mask 10 includes a step of heating the support substrate 210. If the support substrate 210 expands or contracts due to the heat treatment, not only will the position of the photoresist layer 230 formed on the support substrate 210 be shifted, but stress may also cause peeling. Therefore, in order to stabilize the manufacturing process of the deposition mask 10, it is more preferable that the support substrate 210 be a rigid substrate with a small thermal expansion coefficient. Examples of materials for the support substrate 210 include stainless steel (such as SUS304 or SUS430), 42 alloy, invar, super invar, and stainless invar. Alternatively, a glass substrate may be used as the support substrate 210.

[0038] The metal layer 220 functions as a base metal in the first electroforming step. The material of the metal layer 220 is, for example, nickel or a nickel alloy. The metal layer 220 is formed by sputtering, electroforming, electroless plating, or the like.

[0039] Note that the metal layer 220 is eventually separated and removed. Therefore, a conductive layer may be provided on the metal layer 220 to facilitate separation of the metal layer 220 from the support substrate 210. In this case, the metal layer 220 can be easily separated from the support substrate 201 by peeling off the conductive layer.

[0040] The deposition mask 10 may be manufactured by electroless plating instead of electroforming. When electroless plating is used, an insulating layer may be used instead of the metal layer 220.

[0041] The photoresist layer 230 functions as a mask in the first electroforming process. The photoresist layer 230 is formed into a desired shape by disposing a photoresist on the metal layer 220 so as to have a predetermined film thickness and developing it. The photoresist may be a dry film resist, which is a film that can be applied and processed, or a liquid coating resist. The photoresist may have either a positive or negative photosensitive characteristic. In the following, a negative photosensitive dry film will be used as an example.

[0042] The photoresist layer 230 has a pattern corresponding to the opening pattern of the mask body 110 of the deposition mask 10. The pattern of the photoresist layer 230 is formed by photolithography. That is, the pattern of the photoresist layer 230 is formed by adhering a photomask to a dry film resist, exposing the dry film to ultraviolet light, and dissolving and removing the unexposed portions.

[0043] Next, the amount of warpage of the support substrate 210 on which the metal layer 220 and the photoresist layer 230 have been formed is measured (see step S412 shown in FIG. 3). The amount of warpage of the support substrate 210 is measured using, for example, a laser displacement sensor. The laser displacement sensor measures the amount of warpage by irradiating the support substrate 210 with laser light and forming an image of the reflected light with a CMOS sensor. The laser displacement sensor obtains data on the amount of warpage in the XY plane of the support substrate 210. The amount of warpage obtained for each coordinate in the XY plane of the support substrate 210 is called warpage amount data. The number of points of warpage amount to be obtained is set appropriately depending on the area of ​​the support substrate 210.

[0044] When measuring the amount of warpage of the support substrate 210, it is preferable to measure the amount of warpage of the support substrate 210 by positioning the support substrate 210 so that the first surface 210a of the support substrate 210 is perpendicular to the horizontal plane. If the support substrate 210 is positioned so that the first surface 210a of the support substrate 210 is parallel to the horizontal plane and the amount of warpage of the support substrate 210 is measured, the amount of warpage will be reduced by the weight of the support substrate 210, making it impossible to measure the amount of warpage accurately. By positioning the support substrate 210 so that the first surface 210a of the support substrate 210 is perpendicular to the horizontal plane, the influence of the weight of the support substrate 210 can be reduced, and the amount of warpage of the support substrate 210 can be measured accurately. If the influence of the weight of the support substrate 210 is small, the first surface 210a of the support substrate 210 may be tilted ±20° from the perpendicular to the horizontal plane.

[0045] Next, a first plating layer 240 is formed on the support substrate 210 (see step S413 shown in FIG. 3). Fig. 4B shows a step of forming the first plating layer 240 using the photoresist layer 230 as a mask. The first plating layer 240 is formed by electroforming (plating).

[0046] The plating solution used in electroforming is usually a solvent in which one or more types of metal salts, organic electrolytes, acids such as phosphoric acid, alkaline substances, and other electrolytes are dissolved. Examples of the solvent include water, alcohols such as methanol and ethanol, cyclic carbonates such as ethylene carbonate and propylene carbonate, linear carbonates such as dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate, and mixed solvents thereof.

[0047] The metal salt may be appropriately selected in consideration of the metal or alloy to be precipitated. Examples of metals in the metal salt include Cu, Zn, Ga, As, Cr, Se, Mn, Fe, Co, Ni, Ag, Cd, In, Sn, Sb, Te, Ru, Rh, Pd, Au, Hg, Tl, Pb, Bi, W, Po, Re, Os, Ir, and Pt. Among these, Ni, Ag, Au, Cd, Co, Cr, Cu, Fe, Sn, and Zn are preferred, and Ni is particularly preferred. These metals may be used alone or in combination of two or more.

[0048] Specific examples of metal salts that are the main components of plating solutions include nickel sulfate, nickel sulfate, nickel chloride, nickel sulfamate, and nickel chloride for nickel plating solutions. These metal salts may be used alone or in combination. Cobalt sulfamate may be added to the nickel plating solution.

[0049] In the first electroforming step, the metal layer 220 and the photoresist layer 230 are placed in an electroforming tank containing the plating solution prepared under predetermined conditions. Then, metal plating is formed from the surface of the metal layer 220 that is not covered by the photoresist layer 230 to the height of the photoresist layer 230. Examples of materials for the first plating layer 240 include nickel and nickel alloys.

[0050] In this embodiment, nickel sulfamate is preferably used as the metal salt. By using nickel sulfamate as the metal salt and adjusting the current density, the internal stress of the deposited nickel film can be adjusted. Furthermore, the internal stress may be reduced by adding a stress reducer such as saccharin to the plating solution.

[0051] Furthermore, the internal stress of the nickel film can be adjusted by adding impurities to the nickel plating solution. Compressive stress can be generated in the nickel film by adding, as an organic chemical species, a compound containing a sulfur atom in its molecule to the nickel plating solution. Tensile stress can be generated in the nickel film by adding, as an inorganic chemical species, iron (II, III) ions, zinc ions and their hydroxides, or chromate ions, or, as an organic chemical species, 2-butyne-1,4-diol and 2-propyne-1-ol, which have a double bond in their molecule, to the nickel plating solution. When compressive stress is applied to the nickel film, it is preferable to add impurities that generate compressive stress to the nickel plating solution. Furthermore, to adjust the stress of the nickel film, impurities that generate tensile stress may be added in addition to the impurities that generate compressive stress.

[0052] Next, the amount of warpage of the support substrate 210 on which the first plating layer 240 has been formed is measured (see step S414 shown in FIG. 3). The method for measuring the amount of warpage in step S414 is the same as the method for measuring the amount of warpage in step S412. Furthermore, the coordinates of the amount of warpage measured in step S414 correspond to the coordinates of the amount of warpage measured in step S412. This allows data on the amount of warpage in the XY plane to be obtained. In the following description, the amount of warpage measured before the first plating layer 240 is formed will be referred to as the first amount of warpage, and the amount of warpage measured after the first plating layer 240 is formed will be referred to as the second amount of warpage.

[0053] Next, the change in warpage δ is calculated based on the first warpage amount and the second warpage amount before and after the formation of the first plating layer 240. The change in warpage δ can be calculated by subtracting the first warpage amount from the second warpage amount for each coordinate. Next, the internal stress σ of the first plating layer 240 is calculated based on the change in warpage δ (step S415 shown in FIG. 3). The internal stress σ of the first plating layer 240 is calculated by the following formula (1):

[0054]

number

[0055] In formula (1), Es represents the Young's modulus of the support substrate 210, b represents the thickness of the support substrate 210, ν represents the Poisson's ratio of the support substrate 210, L represents the distance from a reference point of the support substrate 210, and d represents the thickness of the first plating layer 240. Based on formula (1), the internal stress σ can be calculated for each coordinate in the XY plane. The internal stress σ calculated for each coordinate in the XY plane of the support substrate 210 is referred to as internal stress data. The internal stress data for each coordinate has a one-to-one relationship with the amount of warpage at that coordinate. However, the internal stress data may be calculated for all coordinates, or, based on the assumption that the amount of change in stress within the surface of the support substrate is constant, stress values ​​at other coordinates may be approximated based on the relationship between the stress values ​​and the amount of warpage at several points sampled within the surface.

[0056] Next, the shrinkage rate ε of the first plating layer 240 is calculated based on the internal stress σ of the first plating layer 240 (step S416 shown in FIG. 3). The shrinkage rate ε of the first plating layer 240 is calculated by the following formula (2).

number

[0057] By performing the above calculations on the data of the internal stress in the XY plane, data of the contraction rate ε of the first plating layer 240 in the XY plane can be obtained.

[0058] Next, the shrinkage rate ε of the first plating layer 240 is determined to be within a predetermined range (step S417). The allowable predetermined range of the shrinkage rate ε varies depending on the material of the support substrate, such as the Young's modulus and thickness. For example, if the shrinkage rate ε is within the predetermined range at all of the coordinates of the four corners of the support substrate 210, the shrinkage rate ε may be determined to be within the predetermined range. For example, if the shrinkage rate ε is within the predetermined range at predetermined coordinates other than the coordinates of the four corners of the support substrate 210, the shrinkage rate ε may be determined to be within the predetermined range. If the shrinkage rate ε is determined to be within the predetermined range (step S417; Yes), the process proceeds to step S422, where the photoresist layer 230 is removed. FIG. 4C shows a process of stripping the photoresist layer 230 from the surface of the metal layer 220. The photoresist layer 230 is stripped using, for example, an amine-based stripping solution. This results in the formation of the first plating layer 240 having the opening region 111 and the non-opening region 112.

[0059] The first plating layer 240 formed by electroforming may be polished before stripping off the photoresist layer 230. By polishing the first plating layer 240, the surface of the first plating layer 240 can be flattened.

[0060] The first plating layer 240 corresponds to the mask body 110 of the vapor deposition mask 10. Therefore, hereinafter, the first plating layer 240 will be described as the mask body 110 for convenience.

[0061] Next, a mask frame forming step is performed (step S423). The mask frame forming step will be described in detail later. When the formation of the mask frame is completed, the manufacture of the deposition mask 10-1 is completed. After the step of adjusting the shrinkage rate of the mask body 110 is completed, the process proceeds to step S403 shown in FIG. 2.

[0062] In the manufacturing process of the deposition mask 10-1, if it is determined in step S417 that the shrinkage rate is not within the predetermined range (step S417; No), the process proceeds to step S418. For example, if the shrinkage rate ε is not within the predetermined range at any of the coordinates of the four corners of the support substrate 210, it may be determined that the shrinkage rate ε is not within the predetermined range. For example, even if the coordinates of the four corners of the support substrate 210 are within the predetermined range, if the shrinkage rate ε is not within the predetermined range at any of the coordinates other than the four corners, it may be determined in step S417 that the shrinkage rate ε is not within the predetermined range. In step S418, it is determined whether the shrinkage rate is equal to or greater than a first threshold or equal to or less than a second threshold. Here, the first threshold is a value smaller than the lower limit of the predetermined range, and the second threshold is a value larger than the upper limit of the predetermined range. Like the predetermined range, the first and second thresholds of the allowable shrinkage rate differ depending on the material of the support substrate, such as Young's modulus and thickness. Therefore, for a display device pattern where multiple patterns are arranged on a surface, the values ​​at which the aperture pattern with the greatest positional misalignment deviates from the original aperture pattern by approximately ±1 / 2 of the pixel pitch, relative to a certain location where the misalignment is zero, are referred to as the first and second thresholds. Here, the deposition mask has the relationship of shrinkage rate ∝ stress ∝ tension. If the tension is too large, the deposition mask deforms significantly, making pattern adjustment difficult. Also, if the tension is too small, the mask itself expands when the mask temperature rises during the deposition process, causing the tension to drop to zero and the mask to sag.

[0063] If it is determined that the shrinkage rate is equal to or greater than the first threshold value or equal to or less than the second threshold value (step S418; No), and adjust the drawing coordinates of the predetermined pattern of the (N+1)th photoresist layer so that the calculated shrinkage rate falls within a predetermined range of shrinkage rates (step S419). Here, since N=1, the drawing coordinates of the predetermined pattern of the photoresist layer in the manufacturing process of the next deposition mask 10-2 are adjusted. If the center of the support substrate 210 is used as the reference point, the shrinkage rate tends to increase toward the peripheral region of the support substrate 210. In this case, the magnification of the drawing of the predetermined pattern may be increased from the reference point (coordinate O) of the support substrate 210 toward the peripheral region. In other words, the magnification of the drawing of the predetermined pattern may be linearly increased from the reference point on the support substrate 210 toward the peripheral region. The drawing coordinates are changed by increasing the magnification of the drawing of the predetermined pattern. Furthermore, the uniformity of the film thickness of the first plating layer 240 in the XY plane affects the shrinkage rate in the XY plane. Therefore, in the XY plane, the magnification of the drawing of the predetermined pattern may be increased in areas with a relatively high shrinkage rate, and may be decreased in areas with a relatively low shrinkage rate. Alternatively, the support substrate 210 may be divided into multiple regions, and a predetermined pattern magnification may be set for each region. The reference point of the support substrate 210 does not have to be the center of the support substrate 210, but may be the point or region with the smallest shrinkage rate among the shrinkage rate data of the first plating layer 240 in the XY plane. Adjusting the drawing coordinates of the predetermined pattern of the (N+1)th photoresist layer completes the process in step S402. Thereafter, to manufacture the (N+1)th mask body, the process in step S402 may be started from step S411.

[0064] In step S418, when it is determined that the shrinkage rate of the two-dimensional data of the shrinkage rate ε is less than the first threshold value or exceeds the second threshold value (step S418; Yes), and adjust the conditions of the first electroforming process so that the calculated shrinkage rate ε falls within a predetermined range (step S420). Here, since N=1, the drawing of a predetermined pattern on the photoresist layer in the manufacturing process of the next deposition mask 10-2 is adjusted. Because the shrinkage rate of the mask body 110 is large, in the first electroforming process, for example, a stress reducer may be added to the plating solution. Also, nickel sulfamate may be used as a metal salt contained in the plating solution to adjust the current density. Also, when a nickel plating solution is used as the plating solution, impurities may be added. As another method of stress adjustment, stress can be adjusted by increasing or decreasing the liquid temperature of the plating solution. Alternatively, multiple stress adjustment methods may be used in combination. Also, the processing time of the first electroforming process may be adjusted. After adjusting the conditions of the (N+1)th first electroforming process, the process in step S402 is completed. Thereafter, to manufacture the (N+1)th (here, second) mask body, the process in step S402 may be started from step S411.

[0065] By performing steps S411 to S420, the shrinkage rate of the Nth manufactured mask body can be used as feedback to the predetermined pattern formation step of the photoresist layer for the (N+1)th mask body to be manufactured next and to the first electroforming step, thereby improving the accuracy of the opening positions of the mask body 110 and stabilizing the manufacturing process.

[0066] In step S403, it is determined whether a loop termination condition is satisfied. The loop termination condition is whether a predetermined number of deposition masks 10 have been manufactured. Here, the predetermined number in step S403 is smaller than the predetermined number in step S401. The predetermined number in step S403 is, for example, the number for returning to the step of adjusting the shrinkage rate of the mask body (step S402) after repeatedly performing the cycle of manufacturing the deposition masks 10 (steps S404 and S405). After manufacturing the predetermined number of deposition masks 10, the shrinkage rate of the mask body 110 is inspected for abnormalities. If an abnormality is found in the shrinkage rate of the mask body 110, the shrinkage rate can be adjusted early. Therefore, if the predetermined number of deposition masks 10 has been manufactured (step S403; Yes), the process returns to step S402 to inspect for abnormalities in the shrinkage rate of the mask body 110. If the predetermined number of deposition masks 10 has not been manufactured (step S403; No), the process returns to step S402.

[0067] Through the above steps, the deposition mask 10 can be manufactured.

[0068] In a method for manufacturing a deposition mask according to one embodiment of the present invention, instead of forming a plating layer on a dummy support substrate for measurement and then peeling it off from the support substrate to measure the shrinkage percentage, a first plating layer 240 (mask body 110) to be used as a product is formed, and the shrinkage percentage of the first plating layer 240 can be calculated without peeling the first plating layer 240 from the support substrate. This allows measurement to be performed at the same thickness as the plating layer that constitutes the mask body 110. Therefore, the shrinkage percentage can be evaluated more accurately than when measuring the shrinkage percentage using a dummy substrate. Furthermore, since the calculated shrinkage percentage can be used to correct the conditions of a predetermined pattern or the conditions of the first electroforming process, feedback can be performed early.

[0069] In a method for manufacturing a deposition mask according to one embodiment of the present invention, the conditions of the predetermined pattern or the electroforming conditions may be changed. Changing the electroforming conditions each time the shrinkage rate of the mask body 110 is adjusted may require a long time to achieve the desired accuracy or for the plating solution to stabilize. This reduces productivity of deposition masks. Therefore, rather than changing the electroforming conditions each time the shrinkage rate of the mask body 110 is adjusted, the shrinkage rate of the mask body 110 is adjusted by changing the conditions of the predetermined pattern of the photoresist layer 230. In areas of the first plating layer 240 where the shrinkage rate is high, the drawing coordinates may be corrected to increase the area of ​​the predetermined pattern. This improves the positional accuracy of the opening areas of the first plating layer 240. Furthermore, when the shrinkage rate of the mask body 110 is high and correction by changing the predetermined pattern is difficult, changing the electroforming conditions can significantly reduce the time required to determine the conditions.

[0070] After manufacturing the mask body 110, only the mask body 110 that has the desired shrinkage rate can be sent to the mask frame forming process. By manufacturing the deposition mask 10 according to this flow, it is possible to determine whether or not the mask should be sent to the mask frame forming process, and it is possible to reduce the number of masks that become defective due to a large shrinkage rate of the mask body 110 after the mask frame is formed and low positional accuracy of the opening region. In other words, it is possible to improve the yield of final shipped products.

[0071] Fig. 5 shows the results of a simulation of the amount of warpage when the mask body 110 is formed using a SUS substrate as the support substrate. Fig. 6 shows the results of a simulation of the amount of warpage when the mask body is formed using a glass substrate as the support substrate. The conditions used for the calculation are as follows:

[0072] The support substrate was a SUS substrate with a Young's modulus Es of 200 GPa, a thickness b of 1 mm, and a size of 1000 mm x 800 mm. The first plating layer formed on the support substrate was a Ni alloy with a thickness d of 5 μm and an internal stress σ of 40 MPa (tensile). The center of the support substrate was set as coordinate O (0,0), and the internal stress σ was calculated every 10 mm in the X direction and every 10 mm in the Y direction.

[0073] The support substrate was a glass substrate with a Young's modulus Es of 77 GPa, a thickness b of 0.5 mm, and a size of 1000 mm x 800 mm. The first plating layer formed on the support substrate was a Ni alloy with a thickness d of 5 μm and an internal stress σ of 40 MPa (tensile). The center of the support substrate was set as coordinate O (0,0), and the internal stress σ was calculated every 10 mm in the X direction and every 10 mm in the Y direction.

[0074] 5 and 6 show the XY plane of the support substrate. Coordinate O(0,0) is the reference point of the support substrate. In FIG. 5, region 301 is the region where the change in warpage is 0 to 0.2, region 302 is the region where the change in warpage is 0.2 to 0.4, region 303 is the region where the change in warpage is 0.4 to 0.6, region 304 is the region where the change in warpage is 0.6 to 0.8, and region 305 is the region where the change in warpage is 0.8 to 1.0. Also, in FIG. 6, region 311 is the region where the change in warpage is 0 to 2, region 312 is the region where the change in warpage is 2 to 4, region 313 is the region where the change in warpage is 4 to 6, region 314 is the region where the change in warpage is 6 to 8, and region 315 is the region where the change in warpage is 8 to 10. The glass substrate has a lower Young's modulus than the SUS substrate, and therefore the amount of change in the amount of warping is greater.

[0075] 5 and 6, the change in the amount of warpage δ increases from the coordinate O(0,0) of the reference point of the substrate toward the coordinates A(-400,500), B(-400,-500), C(400,-500), and D(400,500) of the four corners of the substrate. In other words, the amount of warpage increases from the coordinate O(0,0) of the reference point of the substrate toward the coordinates A(-400,500), B(-400,-500), C(400,-500), and D(400,500) of the four corners of the substrate.

[0076] FIG. 7 is a diagram showing regions 301 to 305 shown in FIG. 5 schematically represented on a support substrate. The amount of change in the amount of warpage increases toward the four corners of the support substrate. Although not shown, when regions 311 to 315 shown in FIG. 6 are also represented on a support substrate, the distribution of the amount of change in the amount of warpage will be similar to that shown in FIG. 7. Therefore, as the shrinkage rate of the mask body 110 increases, the area of ​​the opening region of the mask body 110 decreases, which tends to shift the position (coordinates) of the opening region. By measuring the shrinkage rate of the mask body 110, it is possible to predict the trend in the area of ​​the opening region of the mask body 110. To correct the reduction in area and position (coordinates) of the opening region of the mask body 110, it is possible to adjust the predetermined pattern of the photoresist layer or adjust the conditions of the plating solution.

[0077] FIG. 8 shows an example of photoresist layers 331 to 335 after adjusting the magnification of the predetermined pattern based on the shrinkage rate of the mask body obtained in FIG. 5. The photoresist layers 331 to 335 shown in FIG. 8 are partially illustrated; in reality, the photoresist layers are formed over the entire support substrate. When changing the magnification of the drawing of the predetermined pattern, for example, the magnification may be set so that the magnification increases from region 301 to region 305 in a plan view. Therefore, the area increases from region 301 to region 305. Furthermore, the drawing coordinates of each predetermined pattern are changed so that the area of ​​each predetermined pattern in the peripheral region of the support substrate is larger than the area of ​​each predetermined pattern near the reference point on the support substrate in a plan view. As a result, when manufacturing the next deposition mask 10, a photoresist layer can be formed in which the area of ​​the predetermined pattern changes depending on the amount of warpage of the mask body 110, thereby improving the shape accuracy and position accuracy of the opening region in the XY plane of the mask body 110.

[0078] Next, the mask frame forming step will be described with reference to FIGS. 9A to 9E.

[0079] 9A and 9B are diagrams illustrating the mask frame adhesion process. As shown in FIG. 9A, a protective layer 250 is formed on the opening region 111 of the mask body 110. The protective layer 250 can prevent particles generated in a process described below from entering the openings 113 of the opening region 111 and blocking the openings 113. The protective layer 250 can also function as a mask in the second electroforming process described below. The protective layer 250 is made of the same material as the photoresist layer 230.

[0080] 9B, an adhesive layer 280 is provided on the non-opening region 112 of the mask body 110, and the mask frame 120 is adhered onto the adhesive layer 280. The adhesive layer 280 does not need to be completely hardened, as it will be removed in a later step. Examples of materials that can be used for the adhesive layer 280 include vinyl acetate resin, ethylene vinyl acetate resin, epoxy resin, cyanoacrylate resin, and acrylic resin.

[0081] FIG. 9C is a diagram illustrating the second electroforming step. As shown in FIG. 9C, a second plating layer 270 is formed to connect the mask body 110 and the mask frame 120. The second plating layer 270 can be formed by electroforming, which applies current to the metal layer 220 or the mask frame 120. The second plating layer 270 can be formed by a method similar to that for the first plating layer 240. The second plating layer 270 is provided so as to fill the openings in the non-opening regions 112, and therefore is in contact with the metal layer 220. The second plating layer 270 also connects the upper and side surfaces of the non-opening regions 112 of the mask body 110 to the mask frame 120. In other words, the second plating layer 270 corresponds to the connection portion 130 of the deposition mask 10. Therefore, for convenience, the second plating layer 270 will be described below as the connection portion 130.

[0082] 9D and 9E are diagrams illustrating the process of separating the support substrate. As shown in Fig. 9D, the protective layer 250 is peeled off. The protective layer 250 can be peeled off in the same manner as the photoresist layer 230.

[0083] 9E, the support substrate 210 and the metal layer 220 are separated from the mask body 110. The support substrate 210 and the metal layer 220 may be separated at the same time, or the metal layer 220 may be separated after the support substrate 210 is separated.

[0084] Through the above steps, the deposition mask 10 in which the mask frame 120 and the connecting portion 130 overlap with the mask body 110 can be fabricated.

[0085] The order of steps in the manufacturing method of the deposition mask 10 is not limited to the above. For example, the formation of the protective layer 250 shown in Fig. 9A may be performed after the mask frame 120 shown in Fig. 9B is attached to the mask body. Moreover, the peeling of the protective layer 250 shown in Fig. 9D may be performed after the separation of the support substrate 210 shown in Fig. 9E.

[0086] In this embodiment, a method for forming the mask body 110 by electroplating has been described, but an embodiment of the present invention is not limited to this. The mask body 110 can also be formed using a film formed by other metal foil film formation techniques, such as a film formed by electroless plating or a film formed by sputtering. The film used as the mask body 110 may be patterned by appropriate etching.

[0087] The above-described embodiments of the present invention may be combined as appropriate as long as they are not mutually inconsistent. Furthermore, even if a person skilled in the art adds or deletes components or modifies the design, or adds or omits steps or modifies conditions based on the embodiments, such combinations are included within the scope of the present invention as long as they include the gist of the present invention.

[0088] Even if there are other effects and advantages different from those brought about by the aspects of each of the above-mentioned embodiments, those that are clear from the description in this specification or that can be easily predicted by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0089] 10, 10-1 to 10-3: deposition mask, 110: mask body, 110-1: mask body, 110-2: mask body, 110a: first surface, 110b: second surface, 111: opening region, 112: non-opening region, 113: opening, 120: mask frame, 121: frame portion, 122: crosspiece portion, 130: connecting portion, 210: supporting substrate, 210a: first surface, 210b: second surface, 220: metal layer, 230: photoresist layer, 240: first plating layer, 250: protective layer, 270: second plating layer, 280: adhesive layer, 301 to 305: regions, 311 to 315: regions

Claims

1. forming a photoresist layer having a predetermined pattern on a support substrate via a base metal layer; placing the support substrate so that a first surface of the support substrate is perpendicular to a horizontal plane, and measuring a first warpage amount of the support substrate; forming a mask body by depositing metal by electroforming in an area of ​​the base metal layer where the photoresist layer is not formed; the support substrate is disposed so that a first surface of the support substrate is perpendicular to a horizontal plane, and a second warpage amount of the support substrate is measured; calculating a shrinkage rate of the mask body based on a change in the amount of warpage calculated based on the first amount of warpage and the second amount of warpage and an internal stress of the support substrate calculated based on the change in the amount of warpage; a method for manufacturing a deposition mask, wherein when the shrinkage rate of the mask body is smaller than a lower limit value of a predetermined range and is equal to or larger than a first threshold value, or when the shrinkage rate of the mask body is larger than an upper limit value of a predetermined range and is equal to or smaller than a second threshold value, the method changes drawing coordinates of each of the predetermined patterns on a mask body to be manufactured next according to the shrinkage rate of the mask body.

2. 2. The method for manufacturing a deposition mask according to claim 1, wherein when the shrinkage rate of the mask body is smaller than the lower limit of the predetermined range and is less than the first threshold value, or when the shrinkage rate of the mask body is larger than the upper limit of the predetermined range and exceeds the second threshold value, the electroforming conditions of the mask body to be manufactured next are changed.

3. The method for manufacturing a deposition mask according to claim 1 , further comprising the steps of: peeling off the photoresist layer and forming a mask frame on the mask body when the shrinkage rate of the mask body is within the predetermined range.

4. 2. The method for manufacturing a deposition mask according to claim 1, wherein the drawing coordinates are changed so that an area of ​​the predetermined pattern increases radially from a reference point on the support substrate toward a peripheral region in a plan view.

5. The method for manufacturing a deposition mask according to claim 1 , further comprising changing the drawing coordinates so that an area of ​​the predetermined pattern in a peripheral region of the support substrate is larger than an area of ​​the predetermined pattern in the vicinity of a reference point on the support substrate in a plan view.

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