Alignment mark, method for forming alignment mark, and metal mask with alignment mark

Abstract

To provide an alignment mark formed in mask substrate in which the alignment mark is prevented from disappearing due to a mark body inadvertently dropping out from s mark through hole.SOLUTION: An alignment mark 5 formed in a mask substrate 1 comprises a mark through hole 6 formed through the mask substrate 1 toward the vertical direction, which is the thickness direction, and a mark body 7 filling the mark through hole 6. A slip-off prevention part 9 for restricting movement of the mark body 7 in the vertical direction is formed in an inner wall of the mark through hole 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an alignment mark for detecting the position and / or posture of a detection object, a method for forming an alignment mark, and a metal mask provided with an alignment mark. [Background technology]

[0002] For example, Patent Document 1 (title of invention: Metal mask and manufacturing method thereof) discloses a metal mask equipped with an alignment mark (target mark). The alignment mark in Patent Document 1 is composed of a through-hole formed in a mask substrate made of a thin metal plate in the plate thickness direction, and a dye filled in this through-hole. The through-hole is a stepped hole having a large diameter hole and a small diameter hole, each of which is a straight hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-71637 Summary of the Invention [Problem to be solved by the invention]

[0004] In the alignment mark of Patent Document 1, dye is filled into stepped through-holes. The step catches the dye as it moves from the larger-diameter hole to the smaller-diameter hole, preventing it from falling out of the smaller-diameter side of the through-hole. Furthermore, the dye filled in the smaller-diameter holes exerts an anchoring effect, preventing it from falling out of the larger-diameter side of the through-hole. However, the mask substrate is thin, making it difficult to reliably retain the dye solely through the anchoring effect of the small-diameter holes. Furthermore, deformation, such as bending, of the mask substrate can cause separation between the inner surface of the through-hole and the dye, potentially resulting in the dye falling out. Foreign matter can also enter the separated area, potentially causing the dye to fall out. In particular, when cleaning the mask substrate, friction on the surface of the mask substrate or deformation of the mask substrate can cause cleaning water to enter the separated area, potentially causing the dye to fall out of the through-hole, resulting in the inadvertent loss of the alignment mark.

[0005] An object of the present invention is to prevent the mark body from accidentally falling out of the mark through-hole, causing the alignment mark to be lost, in an alignment mark consisting of a mark through-hole formed in a mask substrate and a mark body filling the mark through-hole. Another object of the present invention is to provide a method for forming the above alignment mark, and a metal mask equipped with the alignment mark. [Means for solving the problem]

[0006] The present invention is directed to an alignment mark 5 formed on a mask substrate 1 having a mask opening 2. The alignment mark 5 is composed of a mark through-hole 6 formed to penetrate the mask substrate 1 in the vertical direction, which is the thickness direction, and a mark body 7 filling the mark through-hole 6. A retaining portion 9 is formed on the inner wall of the mark through-hole 6 to restrict movement of the mark body 7 in the vertical direction. The mark through hole 6 is composed of a downwardly expanding, tapered upper half 6a whose diameter gradually increases downward, and a downwardly tapered lower half 6b whose diameter gradually decreases downward, and a recess 22 that serves as a retaining portion 9 is formed inside the mark through hole 6 at the boundary between the upper and lower halves 6a and 6b, and bulges outward to the left and right. The mark body 7 is composed of a downwardly expanding, truncated conical upper portion 7a that fills the upper half 6a, and a downwardly tapered, truncated conical lower portion 7b that fills the lower half 6b, and is provided in the vertical center with an expanded diameter portion 23 whose outer diameter is larger than the opening dimensions of the upper and lower openings of the mark through hole 6.

[0007] The depth of the upper half portion 6 a is set to half the thickness of the mask substrate 1 .

[0008] The metal mask according to the present invention has the above-described alignment marks 5 formed on a mask substrate 1 made of a thin metal plate.

[0009] The present invention relates to a method for forming an alignment mark 5 on a mask substrate 1 having a mask opening 2. The alignment mark 5 is composed of a mark through-hole 6 formed to penetrate the mask substrate 1 in the vertical direction, which is the thickness direction, and a mark body 7 that fills the mark through-hole 6. The method for forming the alignment mark 5 includes a through-hole forming step of forming the mark through-hole 6 in the mask substrate 1, a base material filling step of filling the mark through-hole 6 with a mark base material 16, and a curing step of curing the filled mark base material 16 to form the mark body 7 so as to fill the mark through-hole 6. In the through-hole forming process, an irradiation device 24 is placed above the mask substrate 1, and laser light is irradiated onto the formation location of the alignment mark 5 on the mask substrate 1, causing a portion of the mask substrate 1 to disappear and forming a depression 26 that becomes the upper half 6a of the mark through-hole 6. Next, the irradiation device 24 is placed below the mask substrate 1 and laser light is irradiated, causing a portion of the lower part of the mask substrate 1 to disappear, thereby forming the lower half 6b of the mark through-hole 6 and forming a through-hole 27 that communicates with the previous depression 26 above. The beam diameter of the laser light irradiated from the irradiation device 24 gradually increases with increasing distance from the irradiation device 24, and the mark through hole 6 formed in the through hole forming process is composed of an upper half 6a that tapers downward and widens downward, the diameter of which gradually increases downward, and a lower half 6b that tapers downward and narrows downward, and is characterized in that recesses 22 that serve as retention portions 9 are formed by bulging outward to the left and right inside the mark through hole 6 at the boundary between the upper and lower halves 6a and 6b. [Effects of the Invention]

[0017] As in the alignment mark 5 of the present invention, when the inner wall of the mark through-hole 6 is formed with a retaining portion 9 that restricts the mark body 7 from moving in the vertical direction, the retaining portion 9 can prevent the mark body 7 from accidentally falling out of the mark through-hole 6 and causing the loss of the alignment mark 5. Therefore, a more reliable alignment mark 5 can be formed on the mask substrate 1.

[0019] When the retaining portion 9 is formed by a recess 22 that protrudes outward in the left and right directions from the inner wall of the mark through hole 6 and forms an expanded diameter portion 23 in the mark body 7, the outer shape of the mark body 7 at the expanded diameter portion 23 can be made larger than the inner shape of the opening of the mark through hole 6 on the upper and lower surfaces of the mask substrate 1, thereby restricting the mark body 7 from moving up and down inside the mark through hole 6. This prevents the mark body 7 from falling out of the mark through hole 6.

[0024] A configuration can be adopted in which the mark through-holes 6 are formed in the mask substrate 1 by laser irradiation. With this, for example, when the mark through-holes 6 are formed by irradiating the upper and lower surfaces of the mask substrate 1 with laser light 25 whose beam diameter increases with increasing distance from an irradiation device 24 that is responsible for laser irradiation, recesses 22 that become the retaining portions 9 and that are formed to protrude outward in the left and right directions can be formed in the inner walls of the mark through-holes 6.

[0027] The present invention can provide a metal mask in which the above-described alignment marks 5 are formed on a mask substrate 1 made of a thin metal plate. This makes it possible to obtain a metal mask with a more reliable alignment mark, in which the mark body 7 does not accidentally fall out of the mark through-hole 6 and the alignment mark 5 does not disappear. [Brief explanation of the drawings]

[0028] [Figure 1]3 is a longitudinal sectional front view of the alignment mark according to the first reference example, and is a cross-sectional view taken along line AA in FIG. 2. FIG. [Figure 2] FIG. 1 is a perspective view of a metal mask having alignment marks according to a first reference example. [Figure 3] 10(a) to 10(e) are diagrams illustrating a method for manufacturing an alignment mark according to a first reference example. [Figure 4] FIG. 10 is a vertical sectional front view of an alignment mark according to a second reference example. [Figure 5] 10(a) to 10(d) are diagrams illustrating a method for manufacturing a mark through-hole that constitutes an alignment mark according to a second reference example. [Figure 6] 1 is a vertical sectional front view of an alignment mark according to a first embodiment of the present invention. [Figure 7] 5(a) to 5(d) are diagrams illustrating a method for manufacturing a mark through-hole that constitutes the alignment mark according to the first embodiment. [Figure 8] FIG. 11 is a vertical sectional front view of an alignment mark according to a third reference example. [Figure 9] 10(a) to 10(d) are diagrams illustrating a method for manufacturing a mark through-hole that constitutes an alignment mark according to a third reference example. [Figure 10] 10A and 10B are a longitudinal sectional front view and a plan view of an alignment mark according to a fourth reference example. [Figure 11] 10(a) to 10(e) are diagrams illustrating a method for manufacturing an alignment mark and a metal mask according to a fifth reference example. [Figure 12] FIG. 13 is a vertical sectional front view of an alignment mark according to a sixth reference example. [Figure 13] 13(a) is a vertical sectional front view of an alignment mark according to a seventh reference example, and FIG. 13(b) is a vertical sectional front view of an alignment mark according to a modified example of the reference example. [Figure 14] FIG. 13 is a vertical sectional front view of an alignment mark according to an eighth reference example. [Figure 15] FIG. 13 is a vertical sectional front view of an alignment mark according to a ninth reference example. [Figure 16]FIG. 23 is a vertical sectional front view of an alignment mark according to a tenth reference example. [Figure 17] FIG. 23 is a vertical sectional front view of an alignment mark according to an eleventh reference example. [Figure 18] FIG. 23 is a longitudinal sectional front view of an alignment mark according to a twelfth reference example. [Figure 19] 13A and 13B are a longitudinal sectional front view and a plan view of an alignment mark according to a thirteenth reference example. [Figure 20] 14A and 14B are a longitudinal sectional front view and a plan view of an alignment mark according to a fourteenth reference example. [Figure 21] 14(a) to 14(d) are diagrams illustrating a method for manufacturing an alignment mark and a metal mask according to a fourteenth reference example. [Figure 22] FIG. 23 is a perspective view of an alignment mark according to a fifteenth reference example. DETAILED DESCRIPTION OF THE INVENTION

[0029] (1st Reference example ) Figures 1 to 3 Nia The first alignment mark was applied to the alignment mark of a metal mask for screen printing. Reference example This indicates Reference example The front, back, left, right, top and bottom in this document refer to the crossed arrows shown in Figures 1 and 2 and the indications of front, back, left, right, top and bottom written near each arrow. As shown in Figure 2, the metal mask is based on a mask substrate 1 made of a metal thin plate formed into a square planar shape, and is provided with a printing pattern section (pattern area) 3 having a group of numerous through holes (mask openings) 2 for ink paste formed in the center by patterning in the desired printing pattern, and a square frame-shaped outer periphery 4 formed to surround this printing pattern section 3. Reference example The metal mask in question is formed by integrally molding the printing pattern portion 3 and the outer peripheral portion 4 by electroforming (plating).

[0030] Alignment marks 5 used for alignment with the printing substrate are formed at each of two corners arranged diagonally on the outer periphery 4. As shown in FIG. 1, each alignment mark 5 consists of a mark through-hole 6 formed through the mask substrate 1 in the vertical direction, which is the thickness direction, and a mark body 7 filling this mark through-hole 6. The alignment marks 5 are recognized by a camera or the like by distinguishing the difference in color tone between the surface of the alignment mark 5 and the surface of the mask substrate 1 around its periphery. To make it easier to identify the alignment marks 5 using a CCD camera or the like, the mark body 7 filling the mark through-hole 6 is made of a resin (mark base material) with a reflectance different from the reflectance of the surface of the mask substrate 1.

[0031] A retaining portion 9 is formed on the inner wall of the mark through-hole 6 in order to restrict the vertical movement of the mark body 7. As shown in Fig. 1, the retaining portion 9 is formed as a convex portion 10 formed to protrude inward from the inner wall of the mark through-hole 6. Due to the presence of this convex portion 10, a portion 11 with a small diameter (reduced diameter portion) is formed in the mark body 7.

[0032] More specifically, as shown in Fig. 2, the upper and lower openings of the mark through-hole 6 facing the upper and lower surfaces of the mask substrate 1 are formed to be circular in plan view. On the other hand, as shown in the cross-sectional view of Fig. 1, the diameter defined by the distance between the opposing inner walls of the mark through-hole 6 in the left-right direction varies in size along the vertical direction. Reference example The mark through-hole 6 in the mark through-hole 6 is composed of an upper half 6a that is shaped like a bowl tapering downward and whose diameter decreases downward, and a lower half 6b that is shaped like a bowl widening downward and whose diameter increases downward, and a protrusion 10 is formed on the inner wall at the boundary between these upper and lower halves 6a and 6b, protruding inward. The upper and lower halves 6a and 6b have approximately the same thickness in the vertical direction, and the protrusion 10 is formed in the vertical center of the inner wall of the mark through-hole 6. The protrusion 10 is formed around the entire periphery of the inner wall, and the diameter defined by the spacing between the protrusions 10 is the smallest throughout the entire mark through-hole 6 in the vertical direction.

[0033] The mark through-hole 6 is filled with a resin that will become the mark base material 16 (see FIG. 3(d)) and then hardened, thereby forming the mark body 7 in the mark through-hole 6. Reference example The mark body 7 is composed of an upper portion 7a having a hemispherical trapezoidal shape that narrows downward and is formed to fill the upper half portion 6a, and a lower portion 7b having a hemispherical trapezoidal shape that widens downward and is formed to fill the lower half portion 6b. A reduced diameter portion 11 is formed in the vertical center of the mark body 7 corresponding to the protrusion 10.

[0034] With the alignment mark 5 configured as described above, the vertical movement of the mark body 7 is restricted by the engagement of the convex portion 10 of the mark through-hole 6 with the outer peripheral surfaces positioned above and below the reduced diameter portion 11 on the mark body 7 side. Therefore, it is possible to prevent the mark body 7 from accidentally falling off the mark through-hole 6.

[0035] From the above, this Reference example The printing metal masks related to this project can contribute to Goal 9 (Industry, innovation and infrastructure - Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation) and Goal 12 (Responsible consumption and production - Ensure sustainable consumption and production patterns) of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0036] Figure 3(a) to (e) show the first Reference example The present invention will now be described with reference to the accompanying drawings, in which: Reference exampleIn this method, mask through-holes 6 for alignment marks 5 are formed by etching a mask substrate 1 prepared by an electroforming process. Specifically, first, as shown in FIG. 3(a), resist films 15 having openings 15a at the positions where alignment marks 5 are to be formed are formed on the top and bottom surfaces of the mask substrate 1 prepared by the electroforming process. More specifically, a photoresist layer is applied or laminated to the top and bottom surfaces of the mask substrate 1, and then a pattern film having a pattern corresponding to the openings is adhered to the mask substrate 1. Then, the mask substrate 1 is baked with an ultraviolet lamp, developed, and dried, thereby forming resist films 15 having openings 15a at the positions where alignment marks 5 are to be formed on the top and bottom of the mask substrate 1, as shown in FIG. 3(a). Next, as shown in FIG. 3(b), etching is performed using an etching solution through the opening 15a of the resist film 15 to form recesses that communicate with the opening 15a from the top and bottom of the mask substrate 1. As shown in FIG. 3(c), a mark through-hole 6 is formed, which is composed of an upper half 6a that narrows downward and a lower half 6b that widens downward (through-hole forming process). At this time, a protrusion 10 that serves as a retaining portion 9 remains in the vertical center of the inner wall of the mark through-hole 6. After removing the resist film 15, as shown in FIG. 3(d), a mark base material 16 made of resin is filled into the mark through-hole 6 so as to fill it (base material filling process). In this base material filling process, the mask substrate 1 is placed on a work table 17, and the mark through-hole 6 is filled with the mark base material 16 while the lower opening of the mark through-hole 6 is closed. Finally, by hardening the mark base material 16 filled in the mark through hole 6, an alignment mark 5 can be formed, which consists of the mark through hole 6 and a mark body 7 consisting of an upper part 7a and a lower part 7b that fill the mark through hole 6, and which has a protrusion 10 on the inner wall of the mark through hole 6 that serves as a removal prevention part 9.

[0037] (2nd Reference example ) Figures 4 and 5 Nia Alignment mark No. 2 Reference example As shown in Figure 4, Reference exampleThe mark through-hole 6 constituting the alignment mark 5 according to the present invention is configured with an upper half portion 6a tapered downwards, the diameter of which gradually decreases as it goes downward, and a lower half portion 6b tapered downwards, the diameter of which gradually increases as it goes downwards, which is the same as that of the first alignment mark 5 mentioned above. Reference example In addition, the upper portion 7a of the mark body 7 filling the upper half portion 6a of the mark through-hole 6 is formed in a truncated cone shape that narrows downward, and the lower portion 7b of the mark body 7 filling the lower half portion 6b of the mark through-hole 6 is formed in a truncated cone shape that widens downward. Other points, such as the fact that the mark body 7 is embedded in the mark through-hole 6 and that a protrusion 10 that serves as a retaining portion 9 that protrudes inward is formed on the inner wall at the boundary between the upper and lower halves 6a and 6b, are different from those of the first embodiment. Reference example is the same as:

[0038] Book Reference exampleThe mark through-holes 6 that constitute the alignment marks 5 are formed by machining the mask substrate 1 (FIG. 5(a)) created by the electroforming process. Specifically, as shown in FIG. 5(b), a drill 19 is driven from above into the mask substrate 1 at the location where the alignment marks 5 are to be formed, to form drill holes 20a in the mask substrate 1. Here, cutting is performed until the head of the drill 19 penetrates through to the underside, and the drill holes 20a thus formed are tapered, narrowing downward. Next, as shown in FIG. 5(c), the drill 19 is driven from below the mask substrate 1 to form drill holes 20b that are tapered and widen upward on the lower side of the mask substrate 1. Of course, the drill holes 20b can also be formed by driving the drill 19 from above with the mask substrate 1 upside down. As a result of the above, as shown in FIG. 5(d), a mark through-hole 6 can be formed. The mark through-hole 6 has an upper half 6a tapered downward, originating from the drilled hole 20a, and a lower half 6b tapered downward, originating from the drilled hole 20b, and a diameter gradually increasing downward. A protrusion 10 serving as the retaining portion 9 can be formed on the inner wall at the boundary between the upper and lower halves 6a and 6b. Furthermore, by filling the mask substrate 1 with a mark base material 16 (see FIG. 3(d)) and curing it, an alignment mark 5 can be formed, as shown in FIG. 4, which includes a mark through-hole 6 formed through the mask substrate 1 and a mark body 7 consisting of an upper portion 7a and a lower portion 7b filling the mark through-hole 6. The mark through-hole 6 has a protrusion 10 serving as the retaining portion 9 on the inner wall of the mark through-hole 6.

[0039] (No. 1 6 and 7 show the first embodiment of the alignment mark according to the present invention. 16, the mark through-hole 6 constituting the alignment mark 5 according to this embodiment is composed of a tapered upper half 6a that widens downward and has a diameter that gradually increases downward, and a tapered lower half 6b that narrows downward and has a diameter that gradually decreases downward. A recess 22 that serves as a retaining portion 9 is formed on the inner wall of the mark through-hole 6 at the boundary between the upper and lower halves 6a and 6b and protrudes outward. The mark body 7 is composed of an upper portion 7a that has a frustum shape that widens downward and fills the upper half 6a, and a lower portion 7b that has a frustum shape that narrows downward and fills the lower half 6b. The mark body 7 has an expanded diameter portion 23 in the vertical center whose outer diameter is larger than the opening dimensions of the upper and lower openings of the mark through-hole 6. In this embodiment, the outer shape (outer diameter dimension) of the mark body 7 in the expanded diameter portion 23 can be made larger than the inner shape (opening dimension) of the opening of the mark through hole 6 on the upper and lower surfaces of the mask substrate 1, thereby preventing the mark body 7 from falling off from the mark through hole 6.

[0040] The mark through-hole 6 constituting the alignment mark 5 of this embodiment is formed by irradiating a mask substrate 1 (FIG. 7(a)) prepared by an electroforming process with a laser. Specifically, as shown in FIG. 7(b), an irradiation device 24 is disposed above the mask substrate 1, and a laser beam 25 is irradiated onto the mask substrate 1 at the location where the alignment mark 5 is to be formed, thereby eliminating a portion of the mask substrate 1 and forming a depression 26. Here, the beam diameter of the laser beam 25 gradually increases with increasing distance from the irradiation device 24, and the depression 26 formed by the laser irradiation has a tapered shape that widens downward. The depth of the depression 26 is set to half the thickness of the mask substrate 1. Next, as shown in FIG. 7(c), an irradiation device 24 is disposed below the mask substrate 1, and a laser beam is irradiated from below onto the location where the alignment mark 5 is to be formed, thereby partially eliminating the lower portion of the mask substrate 1 and forming a through-hole 27 that communicates with the depression 26 above. At this time, the beam diameter of the laser light 25 irradiated from the irradiation device 24 gradually increases with increasing distance from the irradiation device 24, as in the previous example, and the through-hole 27 formed by the laser irradiation has a tapered shape that narrows downward. As a result, as shown in FIG. 7(d), a mark through-hole 6 can be formed, which is composed of an upper half 6a that tapers upward and originates from the upper depression 26 and whose diameter gradually decreases upward, and a lower half 6b that tapers downward and originates from the lower through-hole and whose diameter gradually decreases downward. It is also possible to form the through-hole 27 that communicates with the depression 26 by irradiating the mask substrate 1 with a laser from above while holding it upside down. The mark through-hole 6, which is composed of the depression 26 and the through-hole 27, may also be formed simultaneously by irradiating the mask substrate 1 with a laser from both above and below.

[0041] By filling this mark through-hole 6 with a mark base material 16 (see Figure 3(d)) and hardening it, an alignment mark 5 can be formed, as shown in Figure 6, which consists of a mark through-hole 6 formed through the mask substrate 1 and a mark body 7 filling this mark through-hole 6, and which has a recess 22 on the inner wall of the mark through-hole 6 that serves as a removal prevention portion 9.

[0042] (No. 3 Reference examples ) Figures 8 and 9 Nia Alignment mark number 3 Reference examples As shown in Figure 8, Reference example In the alignment mark 5 according to the present invention, the retaining portion 9 is formed on the inner wall of the mark through-hole 6 and is configured as a rough surface portion 30 with minute irregularities 29. More specifically, the mark through-hole 6 is a straight hole with a uniform outer diameter in the vertical direction, but the entire surface of its inner wall is configured as a rough surface portion 30 with minute irregularities 29. The outer periphery of the mark body 7 enters into the minute irregularities 29 of this rough surface portion 30, and the two (the inner wall of the mark through-hole 6 and the outer periphery of the mark body 7) are engaged with each other by the irregularities. Reference example The alignment mark 5 can improve the frictional engagement force between the two (the inner wall of the mark through-hole 6 and the outer periphery of the mark body 7), thereby restricting the mark body 7 from moving up and down inside the mark through-hole 6. This prevents the mark body 7 from falling out of the mark through-hole 6.

[0043] Book Reference example The mark through-holes 6 that constitute the alignment marks 5 are formed by irradiating a mask substrate (FIG. 9(a)) prepared by an electroforming process with a laser. Specifically, as shown in FIG. 9(b), an irradiation device 24 is disposed above the mask substrate 1, and laser light 25 is irradiated onto the mask substrate 1 at the locations where the alignment marks 5 are to be formed, thereby eliminating portions of the mask substrate 1 and forming mark through-holes 6 that penetrate the mask substrate 1 in the vertical direction. The laser light 25 is set to a straight beam with no change in diameter, and a straight hole with a uniform diameter is formed in the mask substrate 1 in the vertical direction. Next, the mask substrate 1 is placed on the workbench 17, a diffusion prism 32 is placed inside the mark through-holes 6, and the irradiation device 24 is again driven to irradiate the diffusion prism 32 with the laser light 25. The laser light 25 diffused by the diffusion prism 32 is irradiated onto the entire inner wall of the mark through-hole 6, eliminating the surface of the inner wall and forming minute irregularities 29. As a result of the above, as shown in FIG. 9(d), a mark through-hole 6 can be formed that has a rough surface portion 30 made up of minute irregularities 29 on the entire inner wall of the straight hole.

[0044] Furthermore, by filling this mark through-hole 6 with a mark base material 16 (see Figure 3(d)) and hardening it, an alignment mark 5 can be formed, as shown in Figure 8, which consists of a mark through-hole 6 formed through the mask substrate 1 and a mark body 7 filling this mark through-hole 6, and which has a rough surface portion 30 on the inner wall of the mark through-hole 6 consisting of minute irregularities 29 that serve as a removal prevention portion 9.

[0045] (No. 4 Reference examples ) Figure 10 Nia Alignment mark number 4 Reference examples This indicates Reference example In the alignment mark 5 according to the present invention, the retaining portion 9 is composed of a bridge 34 spanning the inner wall of the mark through-hole 6. More specifically, the mark through-hole 6 is a straight hole with a uniform outer diameter in the vertical direction, but the upper and lower ends of the inner wall are each formed with a bridge 34 shaped like a square in plan view, consisting of two ribs 35 running in the left-right direction and two ribs 35 running in the front-rear direction. Furthermore, by filling the mark through-hole 6 with a mark base material 16 (see FIG. 3(d)) and curing it, an alignment mark 5 can be formed, as shown in FIG. 10, which is composed of the mark through-hole 6 formed to penetrate the mask substrate 1 and the mark body 7 filling the mark through-hole 6, and which has bridges 34 serving as the retaining portion 9 on the inner walls of the upper and lower ends of the mark through-hole 6.

[0046] In this way, when the retaining portion 9 is configured with the bridge 34 spanning the inner wall of the mark through-hole 6, the bridge 34 engages with the mark body 7, thereby restricting the mark body 7 from moving up and down inside the mark through-hole 6. Therefore, the mark body 7 can be prevented from falling out of the mark through-hole 6.

[0047] (No. 5 Reference examples ) Figure 11(a)~(e) , 5th reference example The present invention provides a method for manufacturing an alignment mark and a metal mask. Reference exampleIn the present invention, the mask substrate 1 is formed by electroforming, and the process of forming the mask substrate 1 by electroforming and the process of forming the mark through-holes 6 are performed simultaneously. Specifically, as shown in FIG. 11(a), a photoresist layer 39 is applied or laminated onto the upper surface of a matrix 38. Then, a pattern film 40 having pattern openings 40a corresponding to the mask openings 2 and the mark through-holes 6 is adhered to the matrix 38. The resist film is baked with an ultraviolet lamp 41, developed, and dried. The unexposed portions are then removed, forming a resist body 42a corresponding to the mask openings 2 and a resist body 42b corresponding to the mark through-holes 6 on the matrix 38, as shown in FIG. 11(b). Next, as shown in FIG. 11(c), these resist bodies 42a and 42b are used to form an electrodeposited layer 43 on the matrix 38 by electroforming. This allows the mask substrate 1 having the mask openings 2 to be formed simultaneously with the formation of the mark through-holes 6. Next, the resist bodies 42a and 42b are dissolved (swelled) and removed, thereby forming the mask substrate 1 having the mask opening 2 and the mark through-hole 6, as shown in FIG. 11(d).

[0048] Next, as shown in FIG. 11(e), the mask substrate 1 is placed on the work table 17, and a diffusion prism 32 is placed in the mark through-hole 6. Then, the irradiation device 24 is driven to irradiate the diffusion prism 32 with laser light 25, thereby eliminating the surface of the inner wall of the mark through-hole 6 and forming minute irregularities 29. 3 Reference examples 9(d), it is possible to form a mark through-hole 6 having a rough surface portion 30 consisting of minute asperities 29 on the entire inner wall of the straight hole. Furthermore, by filling this mark through-hole 6 with a mark base material 16 (see FIG. 3(d)) and curing it, it is possible to form an alignment mark 5 consisting of the mark through-hole 6 formed through the mask substrate 1 and the mark body 7 filling this mark through-hole 6, as shown in FIG. 8, which has a rough surface portion 30 consisting of minute asperities 29 that serve as a removal prevention portion 9 on the inner wall of the mark through-hole 6.

[0049] (No. 6 Reference examples ) Figure 12 Nia Alignment Mark 5 6 Reference examples This indicates Reference exampleIn the alignment mark 5, the inner wall of the mark through hole 6 constituting the alignment mark 5 is bell-mouth shaped with a curved surface formed by bulging inward in both left and right directions. The most inward-bulging portion of the inner wall of the mark through hole 6 is a protrusion 10 that serves as the retaining portion 9. The mark body 7 filling the mark through hole 6 is shaped like a small drum, with the outer diameter of the vertical center being smaller than the outer diameters of both vertical ends. A reduced-diameter portion 11 is formed in the vertical center of the mark body 7. As described above, the protrusion 10 on the mark through hole 6 side engages with the reduced-diameter portion 11 on the mark body 7 side, restricting the vertical movement of the mark body 7 within the mark through hole 6 and preventing the mark body 7 from accidentally falling out of the mark through hole 6.

[0050] (No. 7Reference examples ) Figure 13(a) Nia Alignment Mark 5 7Reference examples This indicates Reference example In the mark through-hole 6, the upper half 6a is formed in a tapered bell-mouth shape with the inner wall's inclination angle increasing downward, while the lower half 6b is formed in a straight shape with a uniform diameter in the vertical direction. The inner diameter of the lowermost part of the upper half 6a is set smaller than that of the lower half 6b, and the lowermost part of the upper half 6a is formed with a protrusion 10 that serves as a retaining portion 9 extending inward in the left and right directions, and a downward-facing receiving surface 45 is formed around the boundary between the upper half 6a and the lower half 6b. The mark body 7 filling the mark through-hole 6 is formed in a tapered, bottomed shape with the upper part 7a being a concave curved surface with the outer periphery's inclination angle increasing downward, while the lower part 7b is formed in a straight, cylindrical shape with a uniform diameter in the vertical direction. Corresponding to the protrusion 10 of the mark through-hole 6, a reduced-diameter portion 11 with a small outer diameter is formed at the lower end of the upper part 7a. A ring-shaped cylindrical end surface 48 is formed at the upper end of the lower portion 7b so as to protrude outward from the lower end of the upper portion 7a.

[0051] Figure 13(b) shows the 7Reference examples1 shows an alignment mark according to a modified example, in which the diameter (d1) of the receiving surface 45, defined by the inner wall of the lowermost portion 6a of the upper half 6a and the inner wall of the uppermost portion 6b of the mark through-hole 6, is set to be the same as the height (d2) of the upper half 6a. This configuration can be obtained by forming a resist body having substantially the same shape as the lower portion 7b of the mark body 7 on a matrix, and then producing the mask substrate 1 by electroforming. In other words, when electroforming is performed using a resist body having substantially the same shape as the lower portion 7b of the mark body 7, the electroforming speed in the horizontal direction from the upper corner of the resist body and the electroforming speed in the upward direction from the upper end of the resist body are substantially the same. Therefore, the dimension d1 resulting from the amount of electroforming in the horizontal direction and the dimension d2 resulting from the amount of electroforming in the upward direction can be made substantially the same.

[0052] In the alignment mark 5 configured as described above, the reduced diameter portion 11 of the mark body 7 is received by the convex portion 10 of the mark through hole 6, thereby restricting downward movement of the mark body 7. Furthermore, the cylindrical end surface 48 of the mark body 7 is received by the receiving surface 45 of the mark through hole 6, thereby restricting upward movement of the mark body 7. As described above, the vertical movement of the mark body 7 within the mark through hole 6 can be restricted, and the mark body 7 can be prevented from accidentally falling out of the mark through hole 6.

[0053] (No. 8 Reference examples ) Figure 14 Nia Alignment Mark 5 8 Reference examples This indicates Reference example In the mark through hole 6, the upper half 6a is formed in a bowl-like shape that narrows downward, with the angle of inclination of the inner wall decreasing downward, while the lower half 6b is formed in a tapered shape with a uniform angle of inclination of the inner wall that widens downward. A protrusion 10 that protrudes inward and serves as a retaining portion 9 is formed on the inner wall at the boundary between the upper and lower halves 6a and 6b. The mark body 7 that fills the mark through hole 6 has an upper portion 7a formed in a hemispherical truncated shape that narrows downward, with the angle of inclination of the outer periphery decreasing downward, and the lower portion 7b formed in a truncated cone that widens downward. Corresponding to the protrusion 10 of the mark through hole 6, a reduced diameter portion 11 with a small outer diameter is formed at the boundary between the upper and lower portions 7a and 7b.

[0054] In the alignment mark 5 configured as described above, the reduced diameter portion 11 of the mark body 7 is received by the convex portion 10 of the mark through-hole 6, thereby restricting the vertical movement of the mark body 7. As described above, the vertical movement of the mark body 7 within the mark through-hole 6 can be restricted, and the mark body 7 can be prevented from accidentally falling out of the mark through-hole 6.

[0055] (No. 9 Reference examples ) Figure 15 Nia The ninth reference example of the alignment mark 5 is shown. Reference example In the mark through hole 6, the upper half 6a is formed in a bell-mouth shape that narrows downward, with the angle of inclination of the inner wall increasing downward, while the lower half 6b is formed in a tapered shape with a uniform angle of inclination of the inner wall that widens downward. A protrusion 10 that protrudes inward and serves as a retaining portion 9 is formed on the inner wall at the boundary between the upper and lower halves 6a and 6b. The mark body 7 that fills the mark through hole 6 has an upper portion 7a that is formed in a tapered shape with a concave curved surface whose angle of inclination of the outer periphery increases downward, while the lower portion 7b is formed in a truncated cone shape that widens downward. Corresponding to the protrusion 10 of the mark through hole 6, a reduced diameter portion 11 with a small outer diameter is formed at the boundary between the upper and lower portions 7a and 7b.

[0056] In the alignment mark 5 configured as described above, the reduced diameter portion 11 of the mark body 7 is received by the convex portion 10 of the mark through-hole 6, thereby restricting the vertical movement of the mark body 7. As described above, the vertical movement of the mark body 7 within the mark through-hole 6 can be restricted, and the mark body 7 can be prevented from accidentally falling out of the mark through-hole 6.

[0057] (1st 0Reference example ) Figure 16 Nia Alignment mark No. 1 0Reference example This indicates Reference example The first feature of the mark through-hole 6 is that a cylindrical straight portion 51 having a uniform diameter in the vertical direction is formed between the upper half portion 6a of a bowl-like shape narrowing downward and the lower half portion 6b of a bowl-like shape widening downward. Reference exampleThe inner peripheral portion of this straight portion 51 is a protrusion 10 that protrudes inward and serves as a retaining portion 9. The mark body 7 that fills the mark through-hole 6 is made up of a hemispherical trapezoid upper portion 7a that narrows downward and fills the upper half portion 6a, a cylindrical portion 52 that fills the straight portion 51 and serves as a reduced diameter portion 11, and lower half 6b and a lower portion 7b in the shape of a hemispherical trapezoid that expands downward and fills the space.

[0058] (1st 1 Reference example ) Figure 17 Nia Alignment mark No. 1 1 Reference example This indicates Reference example The first feature is that both the upper half 6a and the lower half 6b constituting the mark through-hole 6 are straight openings with uniform diameters in the vertical direction, and both the upper part 7a and the lower part 7b constituting the mark body 7 filling the mark through-hole 6 are cylindrical. 0Reference example is different from.

[0059] (1st 2 Reference examples ) Figure 18 Nia Alignment mark No. 1 2 Reference examples This indicates Reference example In the first embodiment, the straight portion 51 constituting the mark through-hole 6 is formed by projecting outward from the inner wall of the upper and lower half portions 6a and 6b to form the recessed portion 22 (retaining portion 9), and the cylindrical portion 52 of the mark body 7 filling the straight portion 51 is formed as the enlarged diameter portion 23. 1 Reference example is different from.

[0060] (1st 3 Reference examples ) Figure 19 Nia Alignment mark No. 1 3 Reference examples This indicates Reference exampleThe inner periphery of the mark through hole 6 is formed in a polygonal shape with numerous continuous irregularities 54 in a plan view, and the outer periphery of the mark body 7 filling the mark through hole 6 is formed in a plan view with numerous irregularities 55. The inner diameter dimension of the mark through hole 6 does not change in the vertical direction, and the mark body 7 filling the mark through hole 6 is a polygonal cylinder with irregularities on the outer periphery. With the alignment mark 5 configured as described above, the contact area between the mark through hole 6 and the mark body 7 can be increased by the amount of the irregularities 54 and 55 formed on the inner and outer peripheries, thereby increasing the frictional engagement force, compared to when the mark through hole 6 is a straight hole with a perfectly circular inner periphery in a plan view and the mark body 7 is a cylindrical body with a uniform diameter. As described above, the irregularities 54 and 55 function as a retaining portion 9, restricting the mark body 7 from moving vertically within the mark through hole 6 and preventing the mark body 7 from accidentally falling out of the mark through hole 6.

[0061] (1st 4 Reference examples ) Figures 20 and 21 Nia Alignment mark No. 1 4 Reference examples As shown in FIG. 20, the inner periphery of the mark through-hole 6 of this reference example is formed in a circular shape with countless minute irregularities 54 continuing in a plan view. Reference example In this case, the number of the irregularities 54 formed on the inner periphery of the mark through-hole 6 is 3 Reference examples The amplitude (width) of each of the irregularities 54 is significantly larger than that of the first irregularity. 3 Reference examples and the inner periphery of the mark through-hole 6 is formed in a circular shape in a plan view. 3 Reference examples In plan view, countless irregularities 55 are formed on the outer periphery of the mark body 7 filling the mark through-hole 6. The inner diameter dimension of the mark through-hole 6 does not change in the vertical direction, and the mark body 7 filling the mark through-hole 6 is cylindrical with irregularities on the outer periphery.

[0062] The alignment mark 5 described above can be obtained by forming minute irregularities on the outer periphery of a resist body 42b used when producing the mask substrate 1 by electroforming. Specifically, as shown in FIG. 21(a), a photoresist layer 39 is applied or laminated on the upper surface of a matrix 38, and then a pattern film 40 having pattern openings 40a corresponding to the mask openings 2 and the mark through-holes 6 is adhered to the upper surface. The resist film 40 is then baked (exposed) with an ultraviolet lamp 41, developed, and dried. The unexposed portions are then removed, forming a resist body 42a corresponding to the mask openings 2 and a resist body 42b corresponding to the mark through-holes 6 on the matrix 38, as shown in FIG. 21(b). By forming minute irregularities on the inner periphery of the pattern openings 40a corresponding to the mark through-holes 6, a minute irregularity 58 can be formed on the outer periphery of the resist body 42b corresponding to the mark through-holes 6, as shown in FIG. 21(b). 21(c), these resist bodies 42a and 42b are used to form an electrodeposited layer 43 on a matrix 38 by electroforming, and then only the resist body 42a is dissolved (swelled) and removed, leaving the resist body 42b, thereby forming an alignment mark 5 as shown in Fig. 20. The alignment mark 5 has a mark through-hole 6 that penetrates the mask substrate 1 and has countless minute irregularities 54 on its inner wall that serve as retention portions 9, and a mark body 7 derived from the resist body 42b that fills the mark through-hole 6 and has countless irregularities 55 on its outer periphery (outer periphery). Alternatively, the alignment mark 5 may be formed by dissolving (swelling) and removing both resist bodies 42a and 42b, and filling the mark through-hole 6 with a mark matrix.

[0063] (1st 5 Reference examples ) Figure 22 Nia Alignment mark No. 1 5 Reference examples This indicates Reference exampleIn the mask substrate 1 shown in FIG. 1, a heat-shielding structure is formed around the alignment mark 5. The heat-shielding structure is composed of a ring-shaped (annular) recessed groove 61 formed in the upper surface of the mask substrate 1 so as to surround the alignment mark 5, and a flat surface 62 formed between the outer periphery of the alignment mark 5 and the recessed groove 61. When a heat-shielding structure is provided around the alignment mark 5 in this manner, it is possible to prevent heat generated when forming the mark through-hole 6 and the rough surface portion 30 by irradiating with laser light from spreading around the mask substrate 1, thereby preventing deformation of the mask substrate 1 when irradiated with laser light. Note that the shape of the recessed groove 61 is not limited to annular, and it may be a square (polygonal) frame shape.

[0064] Although the above embodiments illustrate alignment marks of various shapes, the present invention is not limited to the above embodiments. Specifically, for example, in the first embodiment, the upper and lower halves 6a and 6b of the mark through-hole 6 have substantially the same vertical thickness. However, the upper and lower halves 6a and 6b may have a larger vertical thickness than the other, and the retaining portions 9 (protrusions 10) may be biased toward one side of the mask substrate 1 in the vertical direction. Furthermore, the retaining portions 9 (protrusions 10) may be intermittently formed in the circumferential direction on the inner wall of the mark through-hole 6. In the fifth embodiment, the bridges 34 are provided at the upper and lower ends of the inner wall of the mark through-hole 6. However, the bridges 34 may be formed only at the upper or lower ends, or may be formed in the vertical midpoint of the mark through-hole 6. In the seventh embodiment, a straight hole may be formed in the midpoint of the inner wall (curved surface) of the mark through-hole 6, and a straight portion may be formed in the midpoint of the mark body 7. In the eighth embodiment, a straight hole may be formed at the bottom of the upper half 6a of the mark through-hole 6, and a straight cylindrical portion may be formed between the upper portion 7a and the lower portion 7b of the mark body 7. This configuration can be obtained by forming a resist body having a shape substantially identical to the lower portion 7b of the mark body 7 on a matrix, laminating another resist body having a shape substantially identical to the straight cylindrical portion, and then electroforming the mask substrate 1. In the ninth or tenth embodiment, the lower half 6b of the mark through-hole 6 may be a straight cylindrical portion or tapered downward. Various other embodiments of the present invention are conceivable, such as a combination of the retaining portions 9 of the respective embodiments. The essential point is that the retaining portion 9 that restricts the vertical movement of the mark body 7 is formed on the inner wall of the mark through-hole 6.

[0065] The alignment mark 5 described in each embodiment may be upside down. In the alignment mark of the present invention, the mark body 7 (mark material) does not have to completely fill the mark through-hole 6. Furthermore, the number and positions of the alignment marks formed on the mask substrate of the present invention are not limited to those described in the above embodiments. The number of alignment marks may be one or three or more, and the alignment marks may be positioned within the printing pattern section (pattern area) 3. The shape of the alignment marks formed on the mask substrate of the present invention is not limited to those described in the above embodiments. They may be formed in polygonal or star shapes, etc. The shape of the alignment marks 5 appearing on the top and bottom surfaces of the mask substrate 1 is preferably different from the shape of the openings of the through-holes (mask openings) 2. Furthermore, the shape of the openings of the mark through-holes 6 constituting the alignment mark 5 is preferably different from the shape of the openings of the through-holes (mask openings) 2. The mask substrate of the present invention is not limited to those formed by electroforming (plating). The metal mask of the present invention may be prepared by preparing a metal plate and subjecting it to chemical processing (etching), optical processing (laser irradiation), or mechanical processing (drilling or punching) to form through-holes (mask openings) 2 and mark through-holes 6. By adjusting the composition of the etching agent, the laser irradiation level, or the drill shape and rotation speed, a roughened surface (unevenness) can be formed within each through-hole 2 / 6. The metal mask of the present invention may also be provided with a frame on the outer periphery 4 of the mask substrate 1 or on the outer periphery of the mask substrate 1, with a gauze interposed between them. The marking body (marking material) may be formed from metal (plating, electrodeposition, welding, etc.). Furthermore, the technology of the present invention is not limited to metal masks for printing, but can also be applied to metal masks for evaporation, solder ball array masks, solder ball attraction masks, and other metal masks.

[0066] The diameter dimension of the alignment mark 5 appearing on the upper and lower surfaces of the mask substrate 1 is preferably equal to or greater than the diameter dimension at the opening of the through hole (mask opening) 2 and the diameter dimension at the straight portion extending in the vertical direction of the through hole (mask opening) 2, but it is more preferable to set the diameter dimension of the alignment mark 5 larger than the diameter dimension at the opening of the through hole (mask opening) 2 and the diameter dimension at the straight portion extending in the vertical direction of the through hole (mask opening) 2. [Explanation of symbols]

[0067] 1 Mask substrate 2 Mask opening 5 Alignment marks 6 Mark holes 7 Mark Body 9 Stopper 10 Convex part 16 Mark base material 22 recess 29 Microscopic irregularities 30 Rough surface area 34 Crosslinked product

Claims

1. An alignment mark (5) formed on a mask substrate (1) having a mask opening (2), The mask substrate (1) comprises a mark through-hole (6) formed through the mask substrate (1) in the thickness direction, ie, the vertical direction, and a mark body (7) filling the mark through-hole (6). A retaining portion (9) is formed on the inner wall of the mark through-hole (6) to restrict the mark body (7) from moving in the vertical direction. The mark through hole (6) is composed of an upper half portion (6a) tapered downwards, the diameter of which gradually increases downwards, and a lower half portion (6b) tapered downwards, the diameter of which gradually decreases downwards, and a recess (22) that bulges outward to the left and right and serves as a retaining portion (9) is formed inside the mark through hole (6) at the boundary between the upper and lower halves (6a, 6b). The alignment mark is characterized in that the mark body (7) comprises an upper part (7a) in the shape of a downwardly expanding truncated cone filling the upper half part (6a) and a lower part (7b) in the shape of a downwardly narrowing truncated cone filling the lower half part (6b), and is provided with an expanded diameter part (23) in the vertical center part, the outer diameter of which is larger than the opening dimensions of the upper and lower openings of the mark through hole (6).

2. An alignment mark as described in claim 1, wherein the depth dimension of the upper half (6a) is set to half the thickness dimension of the mask substrate (1).

3. A metal mask characterized in that an alignment mark (5) described in claim 1 or 2 is formed on a mask substrate (1) made of a thin metal plate.

4. A method for forming an alignment mark (5) formed on a mask substrate (1) having a mask opening (2), comprising: The alignment mark (5) comprises a mark through-hole (6) formed through the mask substrate (1) in the vertical direction, which is the thickness direction, and a mark body (7) filling the mark through-hole (6); a through-hole forming step of forming a mark through-hole (6) in a mask substrate (1); a base material filling step of filling the mark through-hole (6) with a mark base material (16); a hardening step of hardening the filled mark base material (16) to form a mark body (7) so as to fill the mark through-hole (6), In the through-hole forming step, an irradiation device (24) is disposed above the mask substrate (1), and a laser beam is irradiated onto the mask substrate (1) at a location where the alignment mark (5) is to be formed, thereby eliminating a portion of the mask substrate (1) and forming a depression (26) that will become the upper half (6a) of the mark through-hole (6); next, an irradiation device (24) is disposed below the mask substrate (1), and a laser beam is irradiated onto the mask substrate (1), thereby partially eliminating the lower portion of the mask substrate (1), thereby forming the lower half (6b) of the mark through-hole (6) and forming a through-hole (27) that communicates with the depression (26) above; The beam diameter of the laser light emitted from the irradiation device (24) gradually increases with increasing distance from the irradiation device (24), A method for forming an alignment mark, characterized in that the mark through hole (6) formed in the through hole forming process is composed of an upper half (6a) that tapers downward and widens downward, the diameter of which gradually increases downward, and a lower half (6b) that tapers downward and narrows downward, the diameter of which gradually decreases downward, and a recess (22) that bulges outward to the left and right and serves as a removal prevention portion (9) is formed inside the mark through hole (6) at the boundary between the upper and lower halves (6a, 6b).

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