Screen mask and method for manufacturing printed matter

Abstract

To provide: a screen mask by which it is possible to improve precision of a printing shape; and a method for manufacturing a printed matter.SOLUTION: A screen mask according to one embodiment includes a mesh that permits transparency of an application material; and a mask film formed on the mesh and provided with a mask opening that is an opening. The mask opening includes at a corner part thereof a release opening from which an edge extends outward.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a screen mask and a printed matter. [Background technology]

[0002] Screen printing, a printing technique, is a method of forming a desired print on a substrate using a screen mask with a predetermined pattern of openings formed from a resin composition on a mesh substrate. This screen printing method is used for various printing processes, such as printing of wiring, electrodes, and fluorescent materials, and is used in a variety of fields, including electronic components.

[0003] In recent years, the miniaturization and high quality of electronic components has led to a demand for higher precision screen masks.

[0004] For example, a screen mask includes a mesh having holes that allow a coating material to pass through, and a mask film having pattern openings provided in the mesh. The pattern openings formed in the mask film are configured to have a shape corresponding to the coating shape of a printing pattern, for example. For example, after an emulsion that forms the mask film is applied to the mesh, the pattern openings are formed by an exposure process. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-129954 Summary of the Invention [Problem to be solved by the invention]

[0006] In such screen masks, for example, depending on the shape of the edges of the printing pattern, it is difficult to achieve the printed shape, and the corners of the edges tend to be rounded. It is particularly difficult to achieve a high-resolution printed shape when the ink viscosity is high. Therefore, there is a demand for a screen mask and a method for manufacturing a printed product that can improve printing accuracy. [Means for solving the problem]

[0007] A screen mask according to one embodiment comprises a mesh that allows the coating material to pass through, and a mask film that is formed on the mesh and has a mask opening that is an opening, and the mask opening has an escape opening at the corner portion with an edge that protrudes outward. [Effects of the Invention]

[0008] According to the embodiments of the present invention, it is possible to provide a screen mask and a method for manufacturing a printed matter that can improve printing accuracy. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view of a screen printing apparatus according to a first embodiment. [Figure 2] FIG. [Figure 3] FIG. 2 is a cross-sectional view showing a configuration of a part of the screen mask according to the embodiment. [Figure 4] 10A and 10B are explanatory diagrams showing the correspondence between the opening shapes and the printing shapes of the screen mask according to the same screen mask and a comparative example. [Figure 5] 4A and 4B are explanatory diagrams showing the printing shapes of the screen mask according to the first embodiment and a comparative example. [Figure 6] FIG. 2 is an explanatory diagram showing the shape of openings in the screen mask according to the first to third embodiments. [Figure 7] FIG. 3 is an explanatory diagram showing the shape of a corner portion of an opening of the screen mask according to the first embodiment. [Figure 8]3A and 3B are explanatory views showing the shape and dimensional relationship of corner portions of openings in the screen mask according to the first embodiment. [Figure 9] FIG. 10 is an explanatory view showing the shape of a corner portion of an opening of a screen mask according to a second embodiment. [Figure 10] 10A and 10B are explanatory views showing the shape and dimensional relationship of corner portions of openings in a screen mask according to a second embodiment. [Figure 11] FIG. 10 is an explanatory view showing the shape of a corner portion of an opening of a screen mask according to a third embodiment. [Figure 12] 10A and 10B are explanatory views showing the shape and dimensional relationship of corner portions of openings in a screen mask according to a third embodiment. [Figure 13] FIG. 10 is a plan view of a screen mask according to a fourth embodiment. [Figure 14] FIG. 10 is a cross-sectional view of a screen mask according to a fourth embodiment. [Figure 15] 10A and 10B are explanatory diagrams showing the shape of openings in a screen mask according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] A screen printing apparatus 10 and a screen mask 20 according to a first embodiment of the present invention will be described below with reference to Figs. 1 to 8. Fig. 1 is a plan view showing the screen printing apparatus 10 according to this embodiment, and Fig. 2 is a cross-sectional view. Fig. 3 is a cross-sectional view of the screen mask 20. Note that in each figure, the configuration is enlarged, reduced, or omitted as appropriate for ease of explanation. In the figures, arrows X, Y, and Z indicate three mutually orthogonal directions.

[0011] As shown in Figures 1 to 3, the screen printing apparatus 10 includes a screen mask 20, a squeegee 13 configured to be movable while in contact with the back surface (other surface) opposite the printing surface of the screen mask 20, a moving unit that moves the squeegee 13, and a support unit 12 that supports the screen mask 20 facing the printing medium.

[0012] The screen printing apparatus 10 forms various printing materials in predetermined patterns on the surface of a printing medium. For example, the screen printing apparatus 10 is used in the manufacture of chip components (capacitors, chip resistors, inductors, thermistors, etc.), touch panels, liquid crystal display (LCD) substrate seals, LTCC (Low Temperature Co-fired ceramics) substrates, solar cell electrodes, and other electronic components.

[0013] 1 to 3, the screen mask 20 includes a frame 21, a mesh 22 that is a base material stretched over the frame 21, and a mask film 23 formed on the mesh 22. In the screen mask 20, the side that faces the surface of the printing medium Ba when printing is performed is called the front side, and the opposite side, the side to which the coating material P is supplied, is called the back side.

[0014] The frame 21 has two pairs of parallel edges and is configured in the shape of a frame with, for example, a rectangular opening of a desired size. The frame 21 supports the outer periphery of the mesh 22, and the mesh 22 is stretched across the opening. In this embodiment, as an example, a frame 21 with an opening dimension of 275 mm in the Y direction and 275 mm in the X direction is used.

[0015] The frame 21 also functions as a frame for holding a predetermined amount of coating material on the rear surface of the mask film 23. The frame 21 and the mesh 22 are joined at the joints with, for example, a synthetic rubber or cyanoacrylate adhesive.

[0016] The mesh 22 is a woven fabric formed by weaving warp threads 22a and weft threads 22b, and has many holes 22c that allow the coating material to pass through. The warp threads 22a and weft threads 22b are wires made of metal such as stainless steel or tungsten, or fibers made of resin such as polyester. The warp threads 22a and weft threads 22b each extend obliquely with respect to the moving direction (first direction) of the squeegee 13, for example.

[0017] A mask film 23 having a predetermined pattern opening 24 (mask opening) is formed on the mesh 22. That is, the mesh 22 holds the mask film 23 in the opening portion of the frame 21.

[0018] The mask film 23 is a layer made of a photocurable resin composition, such as PVA, PVAc, silicone resin, acrylic resin, epoxy resin, polyimide resin, etc. For example, the mask film 23 may have a multilayer structure having multiple layers.

[0019] The thickness of the mask film 23 is set to, for example, 10 μm to 100 μm.

[0020] The mask film 23 is formed on the mesh 22 and is placed in the opening portion of the frame 21. A predetermined pattern opening 24 for printing is formed in the mask film 23 by exposure. The pattern opening 24 constitutes a through-hole that penetrates the mask film 23 in the thickness direction (depth direction). Depending on the material of the mask film 23, through holes may be formed by laser processing to form the pattern openings 24. For example, when the mask film 23 is made of polyimide resin, the predetermined pattern openings 24 for printing are formed by a laser.

[0021] The mask film 23 forms a printed portion where no photosensitive resin is present in the pattern openings 24 and where the coating material can pass through the holes in the mesh 22 from the back surface to the front surface. Areas of the mask film 23 other than the pattern openings 24 and where the holes in the mesh 22 are blocked with photosensitive resin form non-printed portions that do not allow ink as a coating material to pass through. The pattern openings 24 are configured to be able to hold the coating material.

[0022] For example, the shape of the pattern opening 24 can be set appropriately depending on the shape of the printing pattern. For example, it can be set to various shapes such as a slit-shaped line pattern, or an opening with a rectangular or circular shape. The minimum opening width of the pattern opening 24, i.e., the width dimension of the opening at the narrowest part of the pattern opening 24, is 30 μm or less. Here, as an example, the dimensions of the surface of the mask film 23, i.e., the surface facing the printing medium, are used as the reference. As an example, in this embodiment, the pattern shape has multiple identical pattern units arranged in a matrix.

[0023] The pattern opening 24 has a main opening 241 that corresponds to the shape of the printing pattern, and a relief opening 242 that is an enlarged portion with an edge 243 that protrudes outward from a corner of the main opening 241. For example, in this embodiment, the shape of the printing pattern is rectangular, and the main opening 241 has the same shape as the printing pattern.

[0024] As shown in FIGS. 4 to 7, the pattern opening 24 according to this embodiment is a rectangular opening having four sides, and has corner portions 24a at the four corners.

[0025] The relief opening 242 formed by the corner portions 24a are notches 244 cut outward from the four corners of the main opening 241, and the pattern opening 24 has the relief opening 242 extending outward relative to the outline of the corner at a position facing the corner of the image to be printed. In other words, if the intersection of the extensions of a pair of edges 243 in the main opening 241 is taken as a reference intersection C1, for example, the end of the relief opening 242 is positioned at a position shifted a predetermined distance outward from the reference intersection C1. That is, in the pattern opening 24, the pair of edges 243 constituting one corner portion 24a of the four sides constituting the rectangular main opening 241 have a curved portion 243a that curves outward.

[0026] Of the four sides forming the rectangular pattern opening 24, two sides constituting one corner 24a are curved outward at curved portions 243a near the corners 24a. In this embodiment, because relief openings 242 are formed at each of the four corners of the pattern opening 24, the edges 243 of each of the four sides have curved portions 243a that bend outward near the end, leading edges 243b that are closer to the end than the curved portions 243a, and intermediate edges 243c that are regions farther from the end than the curved portions 243a, and the four corners 24a are formed by the leading edges 243b at both ends of the four sides. The vertex Q of each corner 24a is set outside the virtual reference intersection C1 where extensions of the intermediate edges 243c of the two sides intersect. In this embodiment, the extension lines of intermediate edges 243c, 243c that are intermediate portions of the two edges 243, 243 that make up each corner portion 24a extend linearly at an angle of 90 degrees to each other, and the angle of reference intersection C1 where the extension lines of these intermediate edges 243c, 243c intersect is 90°. The vertex Q of the relief opening 242 is configured to be at an acute angle smaller than 90°, outside the opening 24, than the reference intersection C1.

[0027] For example, the relief opening 242 is configured such that the relief distance, which is the distance that the relief opening 242 extends from the edge 243 of the main opening 241 to the outside of the opening, is 5 μm or more and less than 30 μm. In other words, the distance from the curved portion 243 a to the end Q, which is the apex of the edge that becomes the corner portion, is 5 μm or more and less than 30 μm.

[0028] 6 shows the correspondence between the print shape according to this embodiment and other embodiments and the shape and dimensions of the relief opening 242. For example, when the opening shape of the mask film 23 is applied in the same shape as the print pattern, the dimensions of the relief opening 242 are set based on the shape of the edge portion that is actually printed. For example, when printing with a pattern of the shape of Comparative Example 1 that does not have a relief opening, the area of ​​the ink missing portion S1 (ink missing area) is calculated from the R of the corner of the print shape that is generated by the corner of the print shape being overturned, and is calculated as (1-π÷4)×R 2 [mm 2The area of ​​the relief opening 242 formed in the mask film 23, that is, the relief area which is the area of ​​the enlarged portion added to the outside of the reference intersection C1 corresponding to the corner of the print shape, is set to 2 to 20 times the ink missing area.

[0029] For example, as shown in Figure 7, when R = A = B in the shape of this embodiment and the corner is 90 degrees, if the dimension of the missing dimension of the ink missing portion, which is the dimension in the direction of one side from the reference intersection point C1 corresponding to the corner, which is the vertex of the print pattern, to the edge portion of the actual print shape, is B, relative to the dimension R of the actually formed print shape, a square with one side A the same dimension as B is placed on the reference intersection point C1 of the corner, and the position of its diagonal is set as the vertex Q of the escape opening 242, and Q is set as the end of the cutout portion.

[0030] The mesh 22 on which the mask film 23 is formed is configured to be elastically deformable so that it is flexed and deformed by, for example, the pressing force of the squeegee 13 and returns to its original shape when the pressing force is released. With the coating material held in the pattern openings 24 of the mask film 23, the mask film 23 moves toward and away from the printing medium due to the elastic deformation of the mesh 22, and the coating material is transferred from the pattern openings 24 to the printing medium Ba arranged opposite the printing surface side of the mask film 23.

[0031] The squeegee 13 is formed, for example, in the shape of a thin plate from a material such as urethane rubber, silicone rubber, synthetic rubber, metal, or plastic. For example, the squeegee 13 is chamfered to reduce the thickness of its tip. The squeegee 13 is configured to be movable relative to the frame 21. For example, the squeegee 13 has a length that spans the entire length of the area of ​​the mask film 23 in a direction perpendicular to the direction of movement. The tip of the squeegee 13 abuts against the back surface of the screen mask 20 and is pressed against the front surface. When the squeegee 13 moves in the direction indicated by the arrow in FIG. 1 , it presses against the entire surface of the mask film 23 and pushes the coating material out toward the front surface from the pattern openings 24 that have been pre-filled with the coating material.

[0032] The support unit 12 supports the frame 21 in parallel with and at a predetermined distance from the print medium. For example, the support unit 12 includes a plurality of positioning pins 12a that regulate the position of the frame 21. The moving unit moves the squeegee 13 in a predetermined direction at a predetermined speed.

[0033] For example, in a method for manufacturing a screen mask, a photocurable resin is applied as an emulsion to a support material having holes that allow the coating material to pass through, and then formed into a flat plate on the mesh 22. At this time, the thickness varies depending on the number of times it is applied, so multiple applications are repeated as necessary. In addition, the film thickness may be measured after drying, and additional applications may be made if necessary.

[0034] The emulsion layer is then exposed to a predetermined exposure pattern to harden the areas corresponding to the shape of the mask film 23. As an example, the exposure is performed using a maskless exposure machine to perform a maskless exposure process. The exposure machine does not use a photomask, but instead uses an irradiation head to directly draw a drawing pattern based on preset target CAD data onto a screen mask.

[0035] The emulsion layer is patterned as described above, and is subsequently removed in an etching process to form a first removal target portion in the area corresponding to the opening 24 .

[0036] Thereafter, in an etching step (development step), the uncured portions of the mask film 23 are washed away with water or a solvent. This process washes away the uncured portions of the emulsion, forming openings 24 that penetrate from the front surface side to the back surface side in the thickness direction.

[0037] Next, a method for producing a printed matter by a screen printing method using the screen printing apparatus 10 according to this embodiment will be described with reference to Figures 1 and 2. First, the front side of the screen mask 20 is placed facing the surface of the printing medium Ba. At this time, the screen mask 20 is positioned using a positioning member such as a positioning pin 12a.

[0038] Then, a highly viscous paste-like coating material is supplied from the rear surface of the screen mask 20, i.e., the surface opposite the printing medium, to fill the pattern openings 24. For example, the coating material is a highly viscous coating material with an ink viscosity of 50 to 2000 Pa s (shear rate: 1 sec-1).

[0039] Next, a squeegee 13 is placed on the back surface of the screen mask 20, i.e., the surface opposite the printing surface. At this time, for example, the squeegee 13 is placed at a predetermined angle relative to the front surface of the printing medium. Then, the squeegee 13 is moved at a predetermined speed while pressing the mesh 22 and the back surface of the mask film 23 toward the printing medium with a predetermined printing pressure. The squeegee 13 presses against the mask film 23 over the entire back surface of the mask film 23. The pressure of the squeegee 13 causes the pressed portion of the mask film 23 to deform toward the front surface and come into contact with the printing medium. The coating material pressed by the squeegee 13 is pushed out from the pattern openings 24 toward the printing medium as the squeegee 13 passes.

[0040] After the squeegee 13 has passed, the mask film 23 and mesh 22 deform to restore their original shape and separate from the print medium, and some of the coating material P is transferred and remains on the print medium Ba, thereby printing a pattern on the print medium Ba and completing the print. At this time, part of the back side of the coating material remains on the mask film 23 side. The coating material may be any of a variety of materials including, for example, metal or resin, and a variety of materials are used depending on the type of printing object, such as electronic components or displays.

[0041] According to the method for manufacturing the screen mask 20 configured as above, the corners of the printed matter can be formed with high precision by forming the relief openings 242 at the corners of the mask openings 24 of the screen mask.

[0042] For example, if the ink has a high viscosity of 50 to 2000 Pa·s (shear rate: 1 sec-1), it will be difficult for the ink to penetrate into the corners of the pattern openings in the screen mask, and the corners of the printed image will have a rounded shape with a radius of 0.001 to 0.02 mm. However, by providing a cut in the corner that is deeper than the tangent of the edge near the corner, the precision of the printed shape can be improved.

[0043] The configuration and arrangement of the pattern openings 24 are not limited to those described above, and can be changed as appropriate depending on the printing shape.

[0044] For example, in the first embodiment, the shape of the relief opening 242 is an example of a notch that is deeply cut outward from the corner or bend of the print pattern and has one vertex, but the shape is not limited to this. For example, the relief opening 242 may be a cutout that protrudes outward from a predetermined position of the main opening corresponding to the print pattern and has a curved or angular outer edge.

[0045] For example, the relief opening 242A shown in Figures 6 and 8 as a second embodiment is a cutout portion having an angular outer edge and has two vertices. As shown in Figures 6 and 8, the relief opening 242A is configured in an angular shape that protrudes outward from the reference intersection point C1 corresponding to the corner. For example, when R = B = 2a, the relief area of ​​the opening 242A is (5 ÷ 8)R 2 [mm 2 That is, assuming that the corners of the print pattern are 90 degrees and the mask opening has the same shape as Comparative Example 1, and based on the dimension R of the print shape that is actually formed, and the dimension of one side of the ink missing portion is B, one corner of a square with one side a = B / 2 is placed on the reference intersection point C1, and two points on the diagonal line located a = B / 2 outside in each of the X and Y directions are set as the two vertices Q1 and Q2 of the relief opening 242A.

[0046] 6 and 9 as a third embodiment has a curved outer edge. In this embodiment, the outer edge of the relief opening 242B is arc-shaped, and when R = r, the relief area is (3 ÷ 4) π × R 2 [mm 2 That is, when the corners of the print pattern are 90 degrees and the mask opening has the same shape as Comparative Example 1, and the dimension of one side of the ink missing portion is B based on the dimension of R that is actually formed, when a circle with a radius of B is placed with its center at the reference intersection point C1, the outermost circumference is defined as the outer edge of the relief opening 242B.

[0047] Furthermore, in the mask film 23, the pattern opening 24 may be an opening whose cross-sectional shape changes in the depth direction, and the depth of the pattern opening 24 can also be set.

[0048] Furthermore, the mask film 23 may have steps in addition to the pattern openings 24 which are through holes.

[0049] For example, the relief opening 242 is not limited to an opening that penetrates in the thickness direction. For example, as shown in FIGS. 10 and 11 as a fourth embodiment, the relief opening 242D, which is an enlarged portion, may have a shape that protrudes outward in the thickness direction only on a portion of the surface to which the coating material is supplied. In the screen mask 20D according to this embodiment, the side that faces the front surface of the print medium Ba during printing is formed along the shape of the main opening 241D, and the relief opening 242D is formed only on the back surface, which is the side to which the coating material P is supplied. In this embodiment, too, in the corner portion 24a where ink is difficult to flow, ink is supplied to the relief opening 242D, which is a recess that protrudes outward from the reference intersection C1 corresponding to the corner of the print pattern. This makes it easier for ink to flow into the corner portion, thereby ensuring the print shape.

[0050] The print shape can also be changed as appropriate. For example, as shown in Fig. 12, in another embodiment, the pattern shape can be various shapes other than a square, such as a rectangle, a triangle, a pentagon, an octagon, or a line pattern.

[0051] In addition, in each of the above embodiments, a so-called single mesh is exemplified as the mesh 22, but this is not limiting. For example, the mesh 22 may have a so-called combination mesh structure that includes a main mesh 26 and a support mesh 27 provided on the outer periphery of the main mesh 26. Furthermore, the mask film 23 may be formed only on a portion of the central part of the mesh 22, or may be formed over the entire area.

[0052] Furthermore, the features of the different embodiments described above may be combined.

[0053] The present invention is not limited to the above-described embodiments, and in the implementation stage, the components can be modified and embodied without departing from the spirit of the invention.

[0054] In addition, the components illustrated in the above embodiments may be deleted, or the shape, structure, material, etc. of each component may be changed. Various inventions can be created by appropriately combining the multiple components disclosed in the above embodiments. By adjusting the dimensional ratio of the material, the difference in the amount of stretch between the length and width can be reduced, thereby improving printing accuracy. [Explanation of symbols]

[0055] 10...screen printing device, 13...squeegee, 20...screen mask, 21...frame, 22...mesh, 22a...warp thread, 22b...weft thread, 22c...hole portion, 23...mask membrane, 24...pattern opening (mask opening), 26...main mesh, 27...support mesh

Claims

1. A mesh through which the coating material can pass; a mask film formed on the mesh and having a mask opening formed therein; A screen mask, wherein the mask opening has an enlarged portion at a corner portion, the edge of which flares outward.

2. A mesh through which the coating material can pass; a mask film formed on the mesh and having a mask opening formed therein; The screen mask has a main opening corresponding to the shape of a printing pattern and an enlarged portion protruding outward from the main opening.

3. the mask opening has a corner portion where a pair of edges intersect; The screen mask according to claim 1 , wherein at least one of the pair of edges has a curved portion that curves toward an outside of the opening near the corner portion.

4. The screen mask according to claim 1 , wherein the length of the edge constituting the enlarged portion is equal to or greater than 5 μm and less than 30 μm.

5. The screen mask according to claim 1 , wherein the enlarged portion has a notch cut outward.

6. The screen mask according to claim 1 , wherein the enlarged portion has a curved or angular cutout portion in which an end of the edge is curved or bent outward and bulges outward.

7. A screen mask includes a mesh that allows a coating material to pass through, and a mask film that is formed in the mesh and has mask openings that are openings with enlarged portions whose edges protrude outward at corner portions. The mask film holds the coating material, and the coating material is applied from the mask openings of the mask film to a printing medium that is arranged opposite the printing surface side of the mask film, A method for manufacturing a printed matter, which comprises forming a print pattern having a corner portion at a position corresponding to the enlarged portion.

8. The viscosity of the coating material is 50 to 2000 Pa·s, The method for producing a printed matter according to claim 7 , wherein the printed pattern has a line-shaped pattern having an angular or bent portion.

9. The method for producing a printed matter according to claim 7 , wherein the enlarged portion is a cut that is made deeper outside a corner or a bend of the print pattern.

10. The method for producing a printed matter according to claim 7 , wherein the enlarged portion is a cutout portion that protrudes outward from a predetermined position of the main opening corresponding to the print pattern and has a curved or angular outer edge.

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