Screen mask for screen printing, and production method of the same

Abstract

To provide a screen mask for screen printing that improves accuracy of a position while improving reproductivity of printing.SOLUTION: A screen mask for screen printing comprises a mesh constituted by braiding mesh lines that is formed with a stencil composed of an opening and a mask part, where the mesh line of the mask part comprises a core material having a coating layer, the mesh line of the opening comprises a core material, the core material of the mask part is thinner than the core material of the mesh line, and a ratio (Do / Dm) of a diameter Do of the mesh line of the opening to a diameter Dm of the mesh line of the mask part is 0.3 to 0.95.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a screen mask for screen printing and a method for manufacturing the same. [Background technology]

[0002] Conventionally, screen printing masks are manufactured by stretching a screen mesh made of metal fibers such as stainless steel or tungsten or synthetic fibers such as polyester or nylon over a rectangular aluminum pipe or cast frame, coating the surface of the screen mesh with a photosensitive material to a predetermined thickness, overlaying the desired image film on top of this and exposing it to ultraviolet light, and then washing the non-exposed areas with water to develop them, thereby forming a screen printing mask with a pattern. Screen printing is used in a wide range of industries because it allows for thicker printing than other printing methods and the use of functional pastes containing metal or glass particles.

[0003] In particular, ceramic passive components such as low-temperature co-fired ceramics (LTCC), multilayer ceramic capacitors (MLCC), and chip resistors require not only finer and more uniform thickness and height (i.e., print reproducibility) but also extremely high positional accuracy in terms of the printed wiring width, thickness, and height. Therefore, screen meshes made of stretch-resistant metal fibers are used in the areas where printed images are formed. However, due to the accumulation of stress caused by the sliding of the squeegee, the intersections of the weave become misaligned, making it difficult to print large numbers of sheets. To address this issue, a rigidized screen printing mask has been developed that fixes the intersections of the screen mesh and suppresses the stretching of the mesh itself by electrolytically or electrolessly plating metal fibers made of stainless steel or tungsten. This improves positional accuracy by forming a nickel coating of 1 to 3 μm on the surface (Patent Document 1).

[0004] Rigidized screen printing masks minimize the stretching of the screen mesh and the amount of misalignment of intersections during squeegee sliding, allowing for high positional accuracy to be reproduced. However, because a plating film is formed over the entire surface, the threads that make up the screen mesh become 2 to 6 μm thick in diameter, which reduces the permeability of functional inks and metal pastes and reduces printability (i.e., print reproducibility). Patent Document 2 addresses this issue by plating only the outer periphery, leaving the central portion where the print pattern is located unplated. However, while this method improves printability, it also has the problem that the plated outer periphery makes the mesh less stretchable and the lack of plating in the center causes stress from the sliding of the squeegee to be concentrated on the mesh in the center, resulting in misalignment of intersections.

[0005] To address the above-mentioned issues, a method has been disclosed in which a screen mesh is formed from threads that are coated with a removable material in a post-process using a stainless steel or carbon fiber core, and after the screen is made using this, the coating material at the openings is removed (Patent Document 3).However, the method of removing the resin or other material that coats the threads requires that thinner threads be prepared as the original core threads, and currently, such thinning is not possible. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 4-211260 [Patent Document 2] Japanese Patent Application Publication No. 4-151666 [Patent Document 3] Japanese Patent Application Publication No. 10-315648 Summary of the Invention [Problem to be solved by the invention]

[0007] As a result of intensive research, the present inventors have now discovered a screen mask for screen printing in which a stencil consisting of openings and a mask portion is formed on a mesh made of braided mesh wires, wherein the mesh wires in the mask portion are made of a core material having a coating layer, and the mesh wires in the openings are made of a core material (i.e., a core material without a coating layer), and the core material is thinner than the core material of the mesh wires in the mask portion (i.e., a core material having a coating layer), and the diameter D of the mesh wires in the openings is o and the diameter D of the mesh wire in the mask section m The present inventors have developed a screen mask that sets a specific ratio between the thickness of the mask and the thickness of the ink, and have found that this screen mask for screen printing improves printing reproducibility and positional accuracy, thereby completing the present invention.

[0008] Therefore, an object of the present invention is to provide a screen mask for screen printing that improves positional accuracy while improving print reproducibility, and a method for manufacturing the same.

[0009] The present invention includes the following inventions. [1] A screen mask for screen printing in which a stencil consisting of an opening and a mask portion is formed on a mesh made by braiding mesh wires, The mesh wire in the mask portion is made of a core material having a coating layer, The mesh wires in the openings are made of a core material, and the core material is thinner than the core material of the mesh wires in the mask portion, Diameter D of the mesh wire at the opening o and the diameter D of the mesh wire in the mask portion m Ratio to (D o / D m ) is 0.3 to 0.95, a screen mask. [2] Diameter D of the mesh wire at the opening o The screen mask according to [1], wherein the thickness is 8 μm to 25 μm. [3] Diameter of mesh wire at opening D o The diameter D of the core material of the mesh wire in the mask part mcThe screen mask according to [1] or [2], wherein the thickness is 0.1 to 5.0 μm thinner than the thickness of the screen mask. [4] The screen mask according to any one of [1] to [3], wherein the core material is a metal wire. [5] The screen mask according to [4], wherein the metal wire is at least one selected from the group consisting of stainless steel wire, tungsten, and steel wire. [6] The screen mask according to any one of [1] to [5], wherein the coating layer is a metal plating layer. [7] The screen mask according to any one of [1] to [6], wherein the mesh lines in the openings are made of an etched core material. [8] A method for producing a screen mask for screen printing according to any one of [1] to [7], forming a coating layer on the core material of the mesh; a step of masking the mesh wires at the portions corresponding to the mask portions in the mesh with a masking material, and then removing the coating layer of the mesh wires at the portions corresponding to the openings in the mesh; a step of thinning the mesh wires at portions corresponding to the openings in the mesh; removing the masking material; and A process for forming a mask portion A manufacturing method comprising: [9] A method for producing a screen mask for screen printing according to any one of [1] to [7], a step of masking mesh wires in a portion of the mesh corresponding to the openings with a first masking material, then forming a coating layer on the mesh wires in a portion of the mesh corresponding to the masked portion, and then removing the first masking material; a step of masking the mesh wires in the portions corresponding to the mask portions with a second masking material, then thinning the mesh wires in the portions corresponding to the openings, and then removing the second masking material; forming the mask portion A manufacturing method comprising: [Effects of the Invention]

[0010] According to the present invention, there is provided a screen mask for screen printing that improves positional accuracy while improving print reproducibility, and a method for manufacturing the same. In particular, when a metal wire is used as a core material, in a screen printing mask for printing functional ink or metal paste on electrical and electronic components, the mask portion of the stencil has a coating layer such as metal plating, which further improves positional accuracy, and the mesh wires present in the openings of the stencil have a coating layer such as metal plating removed or no coating layer present, and the original metal wires are thinned by etching or the like, thereby eliminating the interference of the mesh wires present in the openings with the transfer of the functional ink or metal paste, thereby further improving print reproducibility such as line width and height. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B are conceptual diagrams showing a portion of a screen mask in which the mesh lines in the mask portion of the stencil are made of a core material with a coating layer, and the mesh lines in the openings of the stencil are made of a core material that is thinner than the core material of the mesh lines in the mask portion. Figure 1A shows a plan view. Figure 1B shows a cross-sectional view of the W-W' portion in the plan view. [Figure 2] A mesh wire 14 is shown consisting of a core material 12 with a coating layer 13. The mesh wire 14 has a diameter Dm and the core material 12 has a diameter Dmc. [Figure 3] A mesh wire 16 is shown, consisting of a thinned core material 15. The diameter of said mesh wire 16 is Do. [Figure 4] 4A and 4B are plan and cross-sectional views of a portion of a screen mask in which the mesh lines in the mask portion of the stencil are made of a core material with a coating layer, and the mesh lines in the opening portion of the stencil are made of a core material. Figure 4A shows the plan view. Figure 4B shows the cross-sectional view of part X-X' in the plan view. [Figure 5]5A and 5B are plan and conceptual diagrams of a portion of a screen mask in which the mesh lines in the mask portion of the stencil are made of a core material and the mesh lines in the openings of the stencil are made of a core material. Fig. 5A shows the plan view. Fig. 5B shows a cross-sectional view of the Y-Y' portion in the plan view. [Figure 6] 6A and 6B are plan and conceptual diagrams of a portion of a screen mask in which the mesh lines in the mask portion of the stencil are made of a core material with a coating layer, and the mesh lines in the opening portion of the stencil are made of a core material with a coating layer. Figure 6A shows the plan view. Figure 6B shows a cross-sectional view of part Z-Z' in the plan view. [Figure 7] Fig. 7 is a diagram showing an outline of a first embodiment of a method for manufacturing a screen mask for screen printing. The left side of Fig. 7 shows a plan view. The right side of Fig. 7 shows a cross-sectional view of part U-U' in the plan view. [Figure 8A-B] 8A-B are diagrams showing an outline of a second embodiment of a method for manufacturing a screen mask for screen printing. The left side of Figures 8A-B shows a plan view. The right side of Figures 8A-B shows a cross-sectional view of part V-V' in the plan view. DETAILED DESCRIPTION OF THE INVENTION

[0012] Screen mask for screen printing In the present invention, there is provided a screen mask for screen printing in which a stencil consisting of openings and a mask portion is formed on a mesh formed by braiding mesh wires, wherein the mesh wires in the mask portion are made of a core material having a coating layer, and the mesh wires in the openings are made of a core material, and the core material of the mesh wires in the openings is thinner than the core material of the mesh wires in the mask portion, and the diameter D of the mesh wires in the openings is o and the diameter D of the mesh wire in the mask portion m Ratio to (D o / D m ) is 0.3 to 0.95.

[0013] According to one embodiment of the present invention, there is provided a screen mask for screen printing in which a stencil consisting of openings and a mask portion is formed on a mesh formed by braiding mesh wires, wherein the mesh wires in the mask portion are made of a core material having a coating layer, and intersections of the mesh wires in the mask portion are fixed by the coating layer of the mesh wires in the mask portion, the mesh wires in the openings are made of a core material, the core material of the mesh wires in the openings is thinner than the core material of the mesh wires in the mask portion, and the diameter D of the mesh wires in the openings is o and the diameter D of the mesh wire in the mask portion m Ratio to (D o / D m ) is 0.3 to 0.95.

[0014] Although the present invention is not particularly limited thereto, one embodiment of the screen mask for screen printing of the present invention will be described below with reference to FIG.

[0015] The screen mask 10 of this embodiment is a screen mask 10 for screen printing in which a stencil 11 consisting of openings 11a and mask portions 11b is formed on a mesh 17 formed by braiding mesh wires 14 made of core materials 12 having coating layers 13, and the mesh intersections are preferably fixed by the coating layers 13 of the mesh wires 14, and the mesh wires 16 in the openings 11a are made of core materials (i.e., core materials having no coating layer) 15, which are thinner than the core materials of the mesh wires in the mask portions, and the diameter D of the mesh wires 16 in the openings 11a is o and the diameter D of the mesh wire 14 in the mask portion m Ratio to (D o / D m ) is 0.3 to 0.95.

[0016] 1 includes a mesh 17 formed by braiding mesh wires 14 stretched within a suitable frame (not shown), and a film-like stencil 11 preferably made of a photosensitive material and including openings 11a and mask portions 11b. Such a screen mask 10 may be a combination mask having a peripheral support (e.g., a polyester mesh) between the mesh 17 formed by braiding mesh wires 14 and the frame.

[0017] Examples of the core material 12 include those with high tensile strength, little stress relaxation, and a low coefficient of thermal expansion so that the tension during stretching can be maintained, those with high strength so that they do not stretch even when slid across a rubber plate called a squeegee, and those with high chemical resistance so that they do not corrode during storage or printing.Specific examples include metal wires such as stainless steel wire and tungsten wire, carbon fiber, and steel wire, with metal wires being preferred, and stainless steel wire and tungsten wire being more preferred.Stainless steel screen meshes in particular are generally commercially available and easy to obtain.

[0018] Diameter (also called wire diameter) D of the core material 12 mc From the viewpoint of printing high-definition patterns, the thickness is, for example, 9 μm to 25 μm, and preferably 11 μm to 23 μm.

[0019] The coating layer 13 can be removably formed on the core material 12. The coating layer 13 can be made of a material that adheres appropriately to the core material, can be formed with a uniform thickness over a wide area, and has different properties from the core material to allow for removal. Specific examples include metal materials (i.e., metal plating) such as nickel, copper, gold, palladium, chromium, zinc, and tin, and organic materials such as synthetic resins (e.g., polyester resin and nylon resin). Metal plating is preferred, and nickel plating and zinc plating are more preferred from the perspective of balancing strength and cost, but are not limited to these. Here, commercially available solutions can be used to remove the coating layer depending on the type of coating layer, and the solution temperature and concentration during treatment can be adjusted appropriately to achieve the desired removal rate. For example, if the coating layer 13 is nickel plating, the nickel plating can be removed using, but is not limited to, nitric acid, a mixture of nitric acid and hydrogen peroxide, or a mixture of sulfuric acid, hydrogen peroxide, and ammonium chloride.

[0020] The thickness of the coating layer 13 can be appropriately selected depending on the thread diameter (diameter) and mesh count of the mesh (preferably a metal mesh) used, the print content, the fixation of the intersections of the mesh lines, etc. Examples of such a thickness include 0.1 μm to 5 μm, and preferably 1 μm to 3 μm.

[0021] According to a preferred embodiment of the present invention, when the core material 12 is a metal wire, the coating layer 13 is a metal plating layer, which may be electrolytic or electroless plating. The thickness of the metal plating layer is preferably 0.1 to 5 μm, more preferably 1 to 3 μm. A thickness of 0.1 μm or more can improve the effect of suppressing misalignment of the intersections, while a thickness of 5 μm or less can shorten the time required to remove the plating by subsequent etching, and can reduce the step between the plated and the removed portion, thereby reducing squeegee wear.

[0022] The diameter D of the mesh wires 14 constituting the mesh 17, i.e., the mesh wires made of the core material 12 having the coating layer 13 mFrom the viewpoint of fixing the intersections of the mesh lines, the thickness is set to, for example, 10 to 26 μm, preferably 12 to 24 μm.

[0023] According to a preferred embodiment of the present invention, the mesh wires 16 in the openings 11a of the stencil 11 are made of a core material 15, which is thinner than the core material 12 of the mesh wires 14 in the mask portion 11b (i.e., the mesh wires 14 are made of a core material 12 having a coating layer 13).

[0024] According to a more preferred embodiment of the present invention, the core material 15 is a metal wire thinned by etching. The etching solution used in the etching process can be a commercially available solution, and the solution temperature, concentration, and other parameters can be adjusted appropriately based on the etching rate. For example, when the core material 15 is a stainless steel wire (preferably a stainless steel wire), the etching solution may be a ferric chloride solution, a mixture of iron (III) chloride, hydrochloric acid, and sodium hypochlorite, or a mixture of hydrochloric acid, nitric acid, and phosphoric acid. For the core material 15 made of tungsten, the etching solution may be an aqueous solution of potassium ferricyanide and potassium hydroxide, a hydrogen peroxide solution containing an organic acid salt, or a mixture of hydrofluoric acid and nitric acid.

[0025] Diameter D of the mesh wire 16 at the opening 11a of the stencil 11 o and the diameter D of the mesh wire 14 in the mask portion 11b m Ratio to (D o / D m ) is, from the viewpoint of improving print reproducibility and positional accuracy, 0.3 to 0.95, preferably 0.5 to 0.9, and more preferably 0.65 to 0.85 or 0.55 to 0.75.

[0026] Diameter D of the mesh wire 16 at the opening 11a of the stencil 11 o is the diameter D of the core material 12 of the mesh wire 14 in the mask portion 11b mcFrom the viewpoint of improving print reproducibility, the thickness may be 0.1 to 5.0 μm thinner (or smaller), preferably 0.5 to 4.0 μm thinner, and more preferably 1.0 to 3.0 μm thinner than the thickness of the first electrode.

[0027] According to one embodiment of the present invention, the diameter D of the mesh wire 16 at the opening 11a of the stencil 11 is o From the viewpoint of improving print reproducibility, the thickness is, for example, 8 μm to 25 μm, preferably 9 μm to 15 μm, and more preferably 10 μm to 12 μm.

[0028] stencil A stencil refers to a coating having holes, where the holes are called openings, and the portion other than the openings (i.e., the coating portion) is called the mask portion. To form a stencil, for example, a photosensitive material (preferably a photosensitive resist) can be applied to a mesh in a conventional manner, dried, and then exposed to light and developed. Examples of such exposure and development include immersing the material in water after exposure to light to dissolve and remove the unexposed portions, or removing the unexposed portions with a water jet from a spray gun and then developing the material.

[0029] The photosensitive material is preferably a photosensitive resist, and more preferably an emulsion-type photosensitive resist. Specific examples include diazo-based photosensitive resins such as direct method emulsions such as "SP-9902," "SP-2021," "SP-2040," "SP-3000," "SP-4000," "SP-8000," "SP-8301," "SP-8305," "SP-9400," "SP-9500," "SP-9600," "SP-9902," and "Toughlex-VH" (all manufactured by Murakami Corporation), SBQ (stilbazolium)-based photosensitive resins such as emulsions such as "OnePot 50M" and "MSP-2" (both manufactured by Murakami Corporation), and "MSFILM" and "MS-DX-W-FILM" (both manufactured by Murakami Corporation) that are pre-coated on polyester film.

[0030] According to one embodiment of the present invention, the opening, aperture ratio, mesh thickness, etc. of the mesh 17 can be appropriately determined taking into consideration, for example, the printing object, printing pattern, printing accuracy, durability, etc.

[0031] The reproducibility of printing using the screen mask for screen printing of the present invention is not particularly limited, but the reproducibility of the height of a printed line with a line width of 25 μm is preferably a printed line height of 10 μm or more, and more preferably a printed line height of 10 μm or more with a variation (standard deviation) of 2 μm or less. The reproducibility of the width of a printed line with a line width of 25 μm is preferably no breaks in the printed line, more preferably no breaks in the printed line and a narrowing of the printed line width of 10 μm or less from the original line width, and even more preferably no breaks in the printed line and a narrowing of the printed line width of 10 μm or less from the original line width, and a variation (standard deviation) of 2 μm or less from the original line width. Here, printing conditions include a printing machine: MT-550TV manufactured by Microtec, a squeegee: Micro squeegee, squeegee hardness: 70 degrees, squeegee angle: 70°, squeegee speed: 50 mm / sec, clearance: 1.2 mm, printing pressure: 0.4 MPa, printing substrate: GCS71 manufactured by Yamamura Photonics Co., Ltd., and paste: DD-1411F-124 manufactured by Kyoto Elex Co., Ltd. The width and height of the printed lines can be measured using a commercially available laser microscope (for example, a VKX-100 manufactured by Keyence Corporation).

[0032] The positional accuracy of printing using the screen mask for screen printing of the present invention is not particularly limited, but it is preferable that all nine recognition marks set in a size of 200 mm x 200 mm in the printing area are printed within 10 μm of the design value.

[0033] Method for manufacturing a screen mask for screen printing According to a first embodiment of the present invention, a method for manufacturing a screen mask 10 for screen printing of the present invention includes the steps of: (1) forming a coating layer on the core material of the mesh; (2) a step of masking the mesh wires in the portions of the mesh corresponding to the mask portions with a masking material, and then removing the coating layer of the mesh wires in the portions of the mesh corresponding to the openings; (3) a step of thinning the mesh wires of the portions corresponding to the openings in the mesh (preferably, thinner than the mesh wires of the core material, more preferably, by further performing an etching treatment); (4) removing the masking material; and (5) forming the mask portion One of the features of the present invention is that it comprises: According to the above-described method for manufacturing a screen mask for screen printing, for example, a screen mask 10 for screen printing shown in FIG. 1 can be manufactured.

[0034] FIG. 7 is a diagram showing an outline of a first embodiment of a method for manufacturing a screen mask for screen printing according to the present invention; (1) forming a coating layer 13 on the core material 12 of the mesh 17; (2) a step of masking the mesh wires of the mesh 17 at the portions 21b corresponding to the mask portions 11b with a masking material 20, and then removing the coating layer 13 of the mesh wires 14 at the portions 21a corresponding to the openings 11a in the mesh 17; (3) A step of thinning the mesh wires (specifically, the core material 12 of the mesh wires 14) of the portions 21a corresponding to the openings 11a in the mesh (preferably, making them thinner than the core material 12, for example, by further performing an etching process); (4) removing the masking material 20; and (5) Step of forming the mask portion 11b This shows an overview of the

[0035] The manufacturing method of the first embodiment of the screen mask is a method in which a coating layer 13 is formed on the core material 12 of the mesh 17, and then the coating layer 13 is removed (preferably peeled off) from the portion 21a corresponding to the opening 11a of the stencil 11.

[0036] Metal plating is preferred as the coating layer 13 in step (1) of the method for producing a screen mask according to the first embodiment.

[0037] The masking material 20 used in step (2) of the screen mask manufacturing method of the first embodiment may be, for example, the above-mentioned photosensitive material, and may be appropriately selected by a person skilled in the art. Specifically, the photosensitive material used for the masking material 20 may be a photosensitive material that is resistant to an etching solution (e.g., concentrated nitric acid) used to remove plating. Examples of such masking materials include diazo-based photosensitive resins and SBQ-based photosensitive resins. Specific examples of diazo-based photosensitive resins include "SP-8301" and "SP-9902" (manufactured by Murakami Corporation), and specific examples of SBQ-based photosensitive resins include "OnePot 50M" and "MSP-2" (manufactured by Murakami Corporation).

[0038] In step (2) of the method for manufacturing a screen mask according to the first embodiment, the coating layer 13 applied to the mesh wires 14 present in the portions 21a corresponding to the openings 11a is removed. The coating layer 13 is preferably plated, and the method for removing the plating can be selected from methods such as immersion and spraying, depending on the properties of the liquid and the etching rate.

[0039] Step (3) in the method for producing a screen mask according to the first embodiment is a step of thinning (preferably by further performing an etching process) the core material 12 of the portion 21a of the mesh 17 corresponding to the openings 11a to form the core material 15. This step is a step of thinning the core material 12 of the mesh wire 14, and from the viewpoint of further improving the permeability of functional inks and metal pastes, it is preferable to further perform an etching process on the metal mesh wire. As with the removal of plating, the etching solution and the process method for the etching process can be selected arbitrarily by a person skilled in the art depending on the type of metal in the mesh wire.

[0040] In step (4) of the method for producing a screen mask according to the first embodiment, the masking material 20 used to remove the plating and thin the mesh lines is removed. To remove the masking material 20, any remover (preferably a stripper) suitable for the masking material 20 can be used. The remover suitable for the masking material 20 depends on the type of masking material 20 to be removed. For example, when the masking material 20 is a diazo-based photosensitive resin such as "SP-9902," an aqueous periodic acid solution can be used.

[0041] In step (5) of the method for manufacturing a screen mask according to the first embodiment, a stencil 11 is formed using a photosensitive material suitable for actual printing. The stencil 11 has openings 11a that allow ink or paste to pass through and mask portions 11b that do not allow ink or paste to pass through. This method can be based on a general method for manufacturing a screen mask.

[0042] According to another embodiment of the present invention, in step (4) of the method for producing a screen mask according to the first embodiment, the masking material 20 used to remove the plating and thin the core material 12 of the mesh wires 14 can be left as is and used as a printing plate. In this case, the masking material 20 used in step (1) must be resistant to the etching solution, as well as having the physical strength (e.g., abrasion resistance) required for printing and resistance to the solvents contained in the ink components. When the masking material 20 is used, steps (4) and (5) do not need to be performed. Examples of such masking materials (photosensitive materials) include diazo-based photosensitive resins such as "SP-8301" and "SP-9902" (manufactured by Murakami Co., Ltd.).

[0043] According to a second embodiment of the present invention, a method for manufacturing a screen mask 10 for screen printing of the present invention includes the steps of: (1') a step of masking the mesh wires of the mesh at the portions corresponding to the openings with a first masking material, then forming a coating layer on the mesh wires of the mesh at the portions corresponding to the masked portions, and then removing the first masking material; (2') a step of masking the mesh wires in the portions corresponding to the mask portions with a second masking material, then thinning the mesh wires in the portions corresponding to the openings to form core material 15, and then removing the second masking material; (3') forming the mask portion One of the features of the present invention is that it comprises: According to the above-described method for manufacturing a screen mask for screen printing, for example, a screen mask 10 for screen printing shown in FIG. 1 can be manufactured.

[0044] FIG. 8 is a diagram showing an outline of a second embodiment of the method for manufacturing a screen mask for screen printing of the present invention, (1') a step of masking the mesh wires (i.e., core material 12) of the portion 21a of the mesh 17 corresponding to the openings 11a with a first masking material 22, and then forming a coating layer 13 on the mesh wires (i.e., core material 12) of the portion 21b of the mesh 17 corresponding to the mask portion 11b, and then removing the first masking material 22; (2') a step of masking the mesh wires of the portion 21b corresponding to the mask portion 11b with a second masking material 20, then thinning the mesh wires of the portion 21a corresponding to the opening 11a (i.e., the core material 12) (preferably thinner than the core material 12) to form the core material 15, and then removing the second masking material 20; (3') Step of forming the mask portion 11b This shows an overview of the

[0045] The method for manufacturing the screen mask of the second embodiment includes the steps of first masking the portion 21a of the mesh 17 corresponding to the opening 11a with a first masking material 22 (plating resist) for plating, then plating the mesh wires of the portion 21b corresponding to the mask portion 11b, and removing (preferably peeling off) the first masking material 22 (plating resist).

[0046] In the method for producing a screen mask according to the second embodiment, the screen mask 10 for screen printing of the present invention is preferably a plate in a form called a combination mask.

[0047] In step (1') of the method for producing a screen mask according to the second embodiment, for example, a first masking material 22 (plating resist) resistant to plating solutions is applied to both sides of a screen mesh 17 made of a metal core material 12 to a thickness of 1 to 10 μm, and then the screen mesh is exposed and developed using a pattern obtained by positive-negative reversal of image data used in creating the stencil, and the mesh lines (i.e., core material 12) in portions 21 a corresponding to openings 11 a are masked with the first masking material 22 (plating resist). Thereafter, a plating (e.g., nickel) coating is formed on the surface to a thickness of 1 to 3 μm by electroplating or electroless plating, and then the first masking material 22 used as the plating resist is removed. Here, the first masking material 22 (plating resist) that is resistant to the plating solution may be a photosensitive material that is resistant to the plating solution, such as a photosensitive material that is acid-resistant and water-resistant at high temperatures, has resolution as needed, and is removable. For example, a diazo-based photosensitive resin may be used, specifically, "SP-8301," "SP-8305," and "SP-9400" (all manufactured by Murakami Corporation). The first masking material 22 may be removed using any suitable remover (preferably, a stripper) for the first masking material 22. The suitable remover for the first masking material 22 depends on the type of first masking material 22 to be removed. For example, when the first masking material 22 is a diazo-based photosensitive resin such as "SP-8301," an aqueous periodic acid solution may be used.

[0048] Step (2') of the method for producing a screen mask according to the second embodiment involves further thinning (preferably by further etching) the mesh wires (i.e., core material 12) of the portion 21a corresponding to the openings 11a in the mesh 17 to form the core material 15, and then removing the masking material. In the above step, after masking the portion 21b corresponding to the mask portion 11b with the etching-resistant second masking material 20, the step of thinning the mesh wires (i.e., core material 12) is preferably a step of further etching the metal mesh wires, from the viewpoint of further improving the permeability of functional inks and metal pastes. The etching solution and the etching method for the etching process can be arbitrarily selected by those skilled in the art depending on the type of metal in the mesh, as in the case of removing plating. The second masking material 20 and the removal solution (preferably a stripper) for removing the second masking material 20 are the same as those used in the first embodiment.

[0049] In step (3') of the method for manufacturing a screen mask according to the second embodiment, a stencil 11 is formed using a photosensitive material or the like that is actually used in printing. The stencil 11 has openings 11a that allow ink or paste to pass through and mask portions 11b that do not allow ink or paste to pass through. This method can be based on a method for manufacturing a general screen mask.

[0050] According to another embodiment of the present invention, in step (2') of the method for producing a screen mask according to the second embodiment, the second masking material 20 may be used as a printing plate without being removed. In this case, the second masking material 20 used in step (2') must have resistance to the etching solution, as well as the physical strength (e.g., abrasion resistance) required for printing and resistance to the solvents contained in the ink components. When the second masking material 20 is used, step (3') does not need to be performed. [Example]

[0051] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples.

[0052] Reference example 1 A combination mask was created using a die-cast aluminum frame with an outer diameter of 450 mm x 450 mm, an inner diameter of 390 mm x 390 mm, and a thickness of 25 mm, a polyester mesh (thread diameter 54 μm, 200 mesh) as an outer support, and a mesh 17 (core material 12 made of SUS304, diameter of core material 12 of 13 μm, 430 mesh) made by braiding mesh wires for forming a printing image, using a method commonly used for manufacturing screen printing masks. For mesh 17 for forming a printed image, nickel plating 13 was formed to a thickness of 2 μm on the surface of core material 12 using an electroless method (mesh 17 was immersed for 20 minutes in an electroless nickel plating solution (temperature 60°C) containing nickel sulfate 30 g / L, sodium acetate 10 g / L, and sodium hypophosphite at concentrations of 10 g / L). Then, a photosensitive resist (SP-9902, manufactured by Murakami Co., Ltd.) was applied as masking material 20 to a thickness of 10 μm, and portions 21b corresponding to mask portions 11b were exposed and developed to form portions 21a corresponding to openings 11a of stencil 11 described below. The mesh wires in portions 21b corresponding to mask portions 11b of stencil 11 described below were masked with masking material 20. Then, by immersing in concentrated nitric acid for 30 seconds, the nickel plating 13 of mesh wires 14 in portions 21a corresponding to openings 11a were etched away, yielding a screen mask using masking material 20. After that, the photosensitive resist used as masking material 20 for removing the plating was removed with a stripping solution made of an aqueous solution of sodium periodate, and then a printing photosensitive resist (Toughlex-VH, manufactured by Murakami Co., Ltd.) was applied to the screen mask to a thickness of 10 μm, and the portion corresponding to mask portion 11b was exposed and developed to create stencil 11 with opening 11a and mask portion 11b. Figure 4 shows a plan view and a cross-sectional view.

[0053] Example 1 A screen mask using the masking material 20 obtained by the method of Reference Example 1 was further immersed in a ferric chloride aqueous solution (20%) for 30 seconds to produce a screen mask having, as mesh wires 16, core material 15 3 μm thinner than the diameter of core material 12 in portions 21a corresponding to openings 11a. The photosensitive resist (SP-9902) used as masking material 20 for removing the plating and etching the core material was then removed using a stripping solution consisting of a sodium periodate aqueous solution. Then, using the same manufacturing method as in Reference Example 1, a printing photosensitive resist (Touhglex-VH) was applied to the screen mask to a thickness of 10 μm, and the portion corresponding to mask portion 11b was exposed and developed to produce a stencil 11 with openings 11a and mask portion 11b formed. A plan view and a cross-sectional view are shown in FIG. 1.

[0054] Comparative Example 1 A combination mask was prepared in the same manner as in Reference Example 1. A stencil 11 was formed in the same manner as in Reference Example 1, except that a printing photoresist (Toughlex-VH, manufactured by Murakami Co., Ltd.) was used instead of nickel plating or applying a masking material 20 to a mesh 17 made of braided mesh wires for forming a printed image (naturally, the plating and masking material 20 were not removed). A plan view and a cross-sectional view are shown in FIG. 5.

[0055] Comparative Example 2 A combination mask was prepared in the same manner as in Reference Example 1. After forming nickel plating 13 by electroless nickel plating on mesh 17, which was made by braiding mesh wires for forming a printed image, stencil 11 was formed using a printing photoresist (Toughlex-VH, manufactured by Murakami Corporation) in the same manner as in Reference Example 1, except that the masking was not performed with masking material 20 and the nickel plating 13 was not removed by etching. Figure 6 shows a plan view and a cross-sectional view.

[0056] Example 2 Similar to Reference Example 1, a combination mask was prepared. For mesh 17 for forming a printed image, nickel plating 13 was formed to a thickness of 2 μm on the surface of core material 12 using an electroless method. Thereafter, a photosensitive resist (SP-8301, manufactured by Murakami Co., Ltd.) serving as masking material 20 was applied to a thickness of 10 μm, and portions 21b corresponding to mask portions 11b were exposed and developed to form portions 21a corresponding to openings 11a of stencil 11 described below, and mesh wires in portions 21b corresponding to mask portions 11b of stencil 11 described below were masked with masking material 20. Thereafter, nickel plating 13 of mesh wires 14 in portions 21a corresponding to openings 11a was etched away by immersion in concentrated nitric acid for 30 seconds, thereby obtaining a screen mask using masking material 20. The screen mask using the obtained masking material 20 was further immersed in a ferric chloride aqueous solution (20%) for 10 seconds to produce a screen mask having core material 15, which was 1 μm thinner than the diameter of core material 12, as mesh wire 16 in portion 21a corresponding to opening 11a. The photosensitive resist (SP-8301) used as masking material 20 for removing the plating and etching the core material was then removed using a stripping solution consisting of a sodium periodate aqueous solution. A printing photosensitive resist (SP-9902, manufactured by Murakami Co., Ltd.) was then applied to the screen mask to a thickness of 10 μm, and the portion corresponding to mask portion 11b was exposed and developed to produce a stencil 11 in which opening 11a and mask portion 11b were formed.

[0057] Printing Test The printing test was carried out under the following conditions:

[0058] Printing conditions: Printing machine: Microtec MT-550TV Squeegee: Micro squeegee Squeegee hardness: 70 degrees Squeegee angle: 70° Squeegee speed: 50mm / sec Clearance: 1.2mm Printing pressure: 0.4 MPa Printing substrate: Yamamura Photonics GCS71 Paste: Kyoto Elex Co., Ltd. DD-1411F-124

[0059] Print reproducibility evaluation To evaluate print reproducibility, the width and height of the 25 μm-wide printed lines created under the above conditions were observed using a laser microscope (Keyence VKX-100). A printed line height of less than 10 μm was evaluated as "x," while a height of 10 μm or greater was evaluated as "good." Furthermore, a printed line height of 10 μm or greater with a height variation of within 2 μm was evaluated as "good." Regarding the width of the printed line, a printed line with breaks due to incomplete transfer of the paste was evaluated as "x." A printed line with no breaks, a narrowing of the printed line width relative to the original line width (25 μm line width) within 10 μm (i.e., a line width greater than 15 μm), and a width variation of more than 2 μm was evaluated as "good." Furthermore, a printed line with no breaks, a narrowing of the printed line width relative to the original line width within 10 μm, and a width variation of within 2 μm was evaluated as "good." The above-mentioned variation refers to the standard deviation when the width and height of a printed line having a line width of 25 μm are measured at 20 points.

[0060] Position accuracy Positional accuracy was checked using nine recognition marks set in a 200mm x 200mm size on the printing area. If all nine recognition marks were printed within 10μm of the design value, they were marked as ◯, and if at least one of the nine recognition marks was printed more than 10μm away from the design value, they were marked as ×. The results are shown in Table 1.

[0061] [Table 1] [Explanation of symbols]

[0062] 10 Screen masks for screen printing 11 Stencils 11a Stencil opening 11b Stencil mask part 12 Core material 13 Coating layer 14 Mesh wire consisting of core material 12 with coating layer 13 15 Thinner core material 16 Mesh wire consisting of core material 15 17 mesh 20 Masking material or second masking material 21 Part corresponding to stencil 11 21a: Portion of stencil corresponding to opening 11a 21b: A portion corresponding to the mask portion 11b of the stencil 22 First masking material

Claims

1. A screen mask for screen printing in which a stencil consisting of an opening and a mask portion is formed on a mesh formed by braiding mesh wires, The mesh wire in the mask portion is made of a core material having a coating layer, The mesh wires in the openings are made of a core material, and the core material is thinner than the core material of the mesh wires in the mask portion, Diameter D of the mesh wire at the opening ｏ and the diameter D of the mesh wire in the mask portion ｍ The ratio (D ｏ / D ｍ ) is 0.3 to 0.

95.

2. Diameter D of the mesh wire at the opening ｏ 2. The screen mask according to claim 1, wherein the thickness is 8 μm to 25 μm.

3. Diameter D of the mesh wire at the opening ｏ The diameter D of the core material of the mesh wire in the mask part ｍｃ 3. The screen mask according to claim 1, wherein the thickness is 0.1 μm to 5.0 μm thinner.

4. 3. The screen mask according to claim 1, wherein the core material is a metal wire.

5. 5. The screen mask according to claim 4, wherein the metal wire is at least one selected from the group consisting of a stainless steel wire, a tungsten wire, and a steel wire.

6. 3. The screen mask according to claim 1, wherein the coating layer is a metal plating layer.

7. 3. The screen mask according to claim 1, wherein the mesh lines in the openings are made of an etched core material.

8. A method for manufacturing a screen mask for screen printing according to claim 1, comprising the steps of: forming a coating layer on the core material of the mesh; a step of masking the mesh wires at the portions corresponding to the mask portions in the mesh with a masking material, and then removing the coating layer of the mesh wires at the portions corresponding to the openings in the mesh; a step of thinning the mesh wires at portions corresponding to the openings in the mesh; removing the masking material; and forming the mask portion A manufacturing method comprising:

9. A method for manufacturing a screen mask for screen printing according to claim 1, comprising the steps of: a step of masking mesh wires in a portion of the mesh corresponding to the openings with a first masking material, then forming a coating layer on the mesh wires in a portion of the mesh corresponding to the masked portion, and then removing the first masking material; a step of masking the mesh wires in the portions corresponding to the mask portions with a second masking material, then thinning the mesh wires in the portions corresponding to the openings, and then removing the second masking material; forming the mask portion A manufacturing method comprising:

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