A suspended metal mask having a dummy pattern and a method for manufacturing a suspended metal mask having a dummy pattern

Abstract

To provide a suspended metal mask with a dummy pattern that is designed to obtain a printed material with little print blurring and thickness difference, by forming a metal film with little thickness difference in the vicinity of a printing opening pattern.SOLUTION: The present invention provides a suspended metal mask with a dummy pattern, in which a first layer is formed of a resin film 10 and a second layer is formed of a metal film 5. A dummy opening pattern 9 is formed so that the metal film 5 as the second layer is formed at least in the vicinity of a printing opening pattern 6 while projecting further to the printed surface side than the resin film 10 as the first layer, and the metal film 5 as the second layer surrounds a printing pattern 7; and the dummy opening pattern 9 is closed with the resin film 10 as the first layer to form a dummy pattern 8.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a suspended metal mask capable of forming a printed pattern with reduced printing bleeding, and a method for manufacturing the same.

Background Art

[0002] The screen printing method is, for example, a so-called stencil printing in which a screen plate having a desired pattern opening formed with a photosensitive resin or the like on a screen mesh stretched with an appropriate tension on a rectangular frame is used, and ink or paste as a printed matter is extruded from the pattern opening onto a printed object with a squeegee or the like to form a desired pattern on the printed object. Since the screen printing method can form a relatively fine pattern at a low cost, it is used in various fields such as decorative printing such as printing the frame portions of touch panels and various lens filters, various functional printing, electrode formation printing of electronic components, wiring printing of printed circuit boards, and the like. However, in the normal screen printing method, so-called printing bleeding may occur, in which the printed pattern deviates from the desired pattern. When printing bleeding occurs, problems such as a poor appearance in decorative printing or an inability to obtain desired characteristics in electrode formation of electronic components, wiring of printed circuit boards, etc. may occur. Therefore, a screen mask (Patent Document ①) that suppresses printing bleeding by forming convex portions at least on the contour portion of the printed pattern has been proposed. By forming convex portions at least on the contour portion of the printed pattern, the convex portions first come into contact with the printed object during printing, and local printing pressure is applied to this portion. Even if there are steps or uneven shapes on the printed object, they fit well with these shapes, improving the sealing property between the printed object and the printed pattern, and effectively suppressing the occurrence of printing bleeding.

Prior Art Documents

Patent Documents

[0003] Note: In the original text, "特許文献1" is not clearly defined. Here, it is left as "Patent Document ①" in the translation for reference. You may need to replace it with the actual patent document number or relevant information according to the specific situation.[Patent Document 1] Japanese Patent Publication No. 2008-162197 (See the claims section, the detailed description of the invention, and Figures 1 and 2) [Patent Document 2] Japanese Patent Publication No. 2014-121804 (See Detailed Description of the Invention {0022} and Figure 12) [Overview of the project] [Problems that the invention aims to solve]

[0004] As described in Patent Document 1, it is possible to suppress some degree of print bleeding by forming protrusions on the contours of areas prone to print bleeding. However, when the protrusions are formed from a photosensitive resin material, even with the technology of Patent Document 1, it has been found that it is difficult to suppress the occurrence of print bleeding in the print pattern portion near the bend of the pattern opening, which is approximately perpendicular to the printing direction, when the print pattern, i.e., the pattern opening of the screen plate, is curved at an angle from a direction approximately perpendicular to the direction of movement of the squeegee, i.e., the printing direction. As an example of the above-mentioned opening pattern, Figure 7(a) shows a schematic front view of a screen plate having a frame-shaped opening pattern as seen from the so-called printing surface side facing the material to be printed, as a prior art example in this specification. Figure 7(b) shows an AA cross-sectional view, and Figure 7(c) shows a printed material. The screen plate is formed by applying a photosensitive emulsion 22 to a screen mesh 21 stretched over a frame (not shown), exposing it using a first-layer forming mask, and then applying a photosensitive emulsion 23 on top of that and exposing it using a second-layer forming mask. The first-layer forming mask forms pattern openings 24. The pattern openings 24 are frame-shaped openings having a bent portion where the first-layer pattern openings 24 bend at an angle from a direction substantially perpendicular to the printing direction to a direction substantially parallel to it. A large number of these frame-shaped pattern openings 24 are arranged on the screen plate in a matrix in the X and Y directions. The second-layer forming mask forms convex patterns 25 near the contours of the numerous frame-shaped pattern openings 24 formed in the first layer. Generally, when screen printing a pattern that has bends that are angled from a direction approximately perpendicular to the printing direction to a direction approximately parallel to the printing direction, the amount of printed material applied tends to be particularly high near the bends, and printing bleeding is likely to occur downstream of the opening in the direction approximately perpendicular to the printing direction. Therefore, an attempt was made to suppress the occurrence of printing bleeding by forming a raised pattern 25 near the contour of the frame-shaped pattern opening 24, but as shown in Figure 7(c), it was not possible to sufficiently suppress the printing bleeding. The cause of the printing bleeding was thought to be the flexibility of the photosensitive resin film and the low smoothness (also called flatness) of the surface of the photosensitive resin film. Therefore, after diligent research, the inventors discovered that the above problem can be solved by performing printing using a suspended metal mask in which a metal film is formed near the printing aperture pattern. After forming a metal film on the printing surface side near the printing aperture pattern by electroplating, a photosensitive resin material is applied from the squeegee side and exposed to light to form a photosensitive resin film that covers at least a portion of the metal film. This makes it possible to obtain a suspended metal mask having a step between the second layer, which is a metal film, and the first layer, which is a photosensitive resin film. The suspended metal mask produced by the above manufacturing method has a so-called convex shape, where the metal film near the print aperture pattern protrudes beyond the photosensitive resin film. Combined with the high flatness characteristic of the metal film, this makes it possible to produce printed materials with suppressed print bleeding. However, upon observation of the printed material after printing, although print bleeding was suppressed, measurements of the thickness of the printed material at several dozen points revealed that the difference in thickness between the thickest and thinnest parts was larger compared to printed materials printed with conventional screen plates where the convex parts were formed with a photosensitive resin film. As a result of further intensive research, the inventors discovered that differences in the thickness of the metal film significantly affect the difference in the thickness of the printed material. When only the metal film near the printing aperture pattern is formed by electroplating, the area where the metal film is formed in the printing pattern portion is small, i.e., the pattern aperture density is high, so the area where the resist film is formed on the matrix becomes very large. Such a printing pattern is sometimes called a negative pattern. On the other hand, since the area around the printing pattern is almost entirely metal film, the pattern aperture density becomes low, and the area where the resist film is formed becomes small. This extreme difference in pattern aperture density between the printing pattern portion and the area around the printing pattern creates a difference in current density during electroplating, resulting in the phenomenon where the electroplating thickness is thicker in the center of the printing pattern and thinner towards the periphery of the printing pattern. As one method to suppress the above phenomenon, a method of forming a dummy aperture pattern with an opening in the periphery of the printing pattern is known (Patent Document 2). When forming a printing pattern by electroplating, a dummy opening pattern is formed over a 16mm to 20mm area of ​​the metal film around the pattern, and the dummy opening pattern is then filled with emulsion to close it. It is believed that deliberately forming an opening pattern around the printing pattern helps to suppress the large difference in electroplating thickness between the center and the periphery of the printing pattern. However, as mentioned above, in the case of a printing pattern called a negative pattern, where the area formed by the metal film is very small, forming a dummy opening pattern over a 16mm to 20mm area was insufficient to suppress the difference in metal film thickness. Another method is to form a dummy opening pattern over the entire area other than the printing pattern and fill the dummy opening pattern with emulsion to close it, but the wider the area of ​​the dummy opening pattern, the higher the possibility of pinholes occurring due to the emulsion closing the dummy opening pattern peeling off and opening up.The occurrence of these pinholes leads to a decrease in print durability, which is one of the characteristics of suspended metal masks. Furthermore, the pinholes can cause the printed material to transfer to areas that are not needed during printing, potentially leading to printing defects and a decrease in product yield. The present invention was made to solve the above-mentioned problems, and provides a suspended metal mask having a dummy pattern that aims to obtain printed materials with less printing bleeding and thickness differences by forming a metal film with little difference in thickness near the printing aperture pattern. [Means for solving the problem]

[0005] The first invention of the present invention, which can achieve the above objective, is a suspend metal mask having a dummy pattern as described in claim 1, and is as follows: In a suspended metal mask in which the first layer is formed of a resin film and the second layer is formed of a metal film, the second layer of metal film is formed at least near the printing opening pattern with the second layer of resin film protruding towards the printing surface side, and the second layer of metal film forms a dummy opening pattern so as to surround the printing pattern, and the dummy opening pattern is closed by the first layer of resin film to form a dummy pattern.

[0006] A second invention of the present invention that can achieve the above objective is a suspended metal mask having a dummy pattern as described in claim 2, and is as follows: In addition to the invention described in claim 1, when the smallest rectangular shape that can accommodate the printing pattern is defined as the external shape of the printing pattern, the dummy pattern is formed outside the external shape of the printing pattern so as to surround the printing pattern, and is formed within a rectangular shape that is larger than the external shape of the printing pattern and similar in shape to the external shape of the printing pattern.

[0007] A third invention of the present invention that can achieve the above objective is a suspended metal mask having a dummy pattern as described in claim 3, and is as follows: In addition to the invention described in claim 2, the dummy pattern is formed outside the external shape of the printing pattern so as to surround the printing pattern, and is formed within a rectangular shape similar to the external shape of the printing pattern, having a perimeter of 1.75 to 2.45 times the perimeter of the external shape of the printing pattern.

[0008] A fourth invention of the present invention that can achieve the above objective is a method for manufacturing a suspended metal mask having a dummy pattern as described in claim 4, and is as follows. A method for manufacturing a suspended metal mask obtained by plating a metal mask and a screen mesh, comprising the steps of: forming a resist formed as a printable opening pattern, a resist formed as a resin film formation opening pattern, and a resist for a dummy opening pattern on a matrix for electroplating; manufacturing a metal mask by electroplating using a matrix for electroplating in which the printable opening pattern, the resin film formation opening pattern, and the dummy opening pattern are formed from resist; integrally joining the metal mask and the screen mesh by electroplating; forming the printable opening pattern, the resin film formation opening pattern, and the dummy opening pattern by peeling the matrix for electroplating and the resist from the metal mask; and filling at least the resin film formation opening pattern and the dummy opening pattern with resin from the squeegee side to close the resin film formation opening pattern and the dummy opening pattern portions, thereby manufacturing a suspended metal mask having a dummy pattern that can transfer a print from the printable opening pattern to a substrate. [Effects of the Invention]

[0009] The suspended metal mask having a dummy pattern and the method for manufacturing the suspended metal mask having a dummy pattern according to the present invention have the configuration described above, and therefore produce the effects described below. (1) The first layer is formed of a resin film, and the second layer is formed of a metal film, with the second layer of metal film protruding more than the first layer of resin film towards the printing surface, at least near the printing opening pattern, so that a printed product with suppressed bleeding can be obtained. Furthermore, since a dummy pattern is formed to surround the printing pattern, the difference in thickness of the metal film is suppressed, and a printed product with less thickness difference can be obtained. (2) The smallest rectangular shape that can accommodate the printing pattern is defined as the external shape of the printing pattern, and the dummy pattern is formed outside the external shape of the printing pattern so as to surround the printing pattern, and is also formed within a rectangular shape similar to the external shape of the printing pattern, having a perimeter of 1.75 times or more and 2.45 times or less the perimeter of the external shape of the printing pattern. This suppresses the difference in thickness of the second layer of metal film and minimizes the area of ​​the dummy pattern, thereby suppressing the occurrence of pinholes caused by the resin film that closes the dummy opening pattern peeling off and opening up. (3) After forming the second layer of metal film on the printing surface side, a photosensitive resin material is applied from the squeegee side and exposed to light, which allows for the formation of the first layer of resin film and the filling of the dummy aperture pattern with resin in one step, thus improving work efficiency. [Brief explanation of the drawing]

[0010] [Figure 1] This shows a schematic front view (a) and a schematic cross-sectional view (b) of the BB portion, as seen from the printing surface side, illustrating one embodiment of the suspend metal mask having the dummy pattern of the present invention. [Figure 2] This is a schematic front view of the printing pattern of a suspended metal mask having a dummy pattern according to the present invention, as seen from the printing surface side. [Figure 3] Figure 2 shows a schematic enlarged view of the CC section (a), a schematic cross-sectional view of the CC section (b), and a schematic cross-sectional view of the boundary between the printable pattern and the dummy pattern in the DD section (c). [Figure 4]Schematic front view of a metal film without a dummy pattern and Table (a) showing the thickness of the metal film within the printing pattern, schematic front view of a metal film when the formation range of the dummy pattern is 1.75 times the perimeter of the printing pattern and Table (b) showing the thickness of the metal film within the printing pattern, schematic front view of a metal film when the formation range of the dummy pattern is 2.45 times the perimeter of the printing pattern and Table (c) showing the thickness of the metal film within the printing pattern. [Figure 5] Schematic front view showing the external shape of a dummy pattern having a shuriken - shaped cross that extends from the center of the metal film towards the four corners of the printing pattern. [Figure 6] Process diagram for explaining the manufacturing method of a suspended metal mask having the dummy pattern of the present invention. [Figure 7] Schematic front view (a), A - A cross - sectional view (b), and diagram (c) showing bleeding of a printed matter, which illustrate the prior art.

Mode for Carrying Out the Invention

[0011] In a suspended metal mask in which the first layer is formed of a resin film and the second layer is formed of a metal film, the metal film of the second layer is formed at least near the printing aperture pattern in a state of protruding toward the printing surface side from the resin film of the first layer, and a dummy aperture pattern is formed so that the metal film of the second layer surrounds the printing pattern, and the dummy aperture pattern is blocked with the resin film of the first layer to form a dummy pattern. A suspended metal mask having a dummy pattern is characterized by this.

Examples

[0012] Hereinafter, an example of the suspended metal mask of the present invention will be described based on the drawings. Note that the dimensions such as thickness and width in FIGS. 1 to 7 of the present embodiment do not show the actual state, but are schematically shown. Also, the present invention is not limited to the following embodiments, and it should be understood that design changes, improvements, etc. can be appropriately added based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. FIG. 1(a) is a schematic front view seen from the printing surface side showing an example of the suspension metal mask 1 having the dummy pattern of the present invention, and FIG. 1(b) is a schematic cross-sectional view of the B-B portion.

[0013] FIG. 1 shows a so-called combination type suspension metal mask in which a printing screen mesh 2 and a support screen mesh 3 are bonded together and stretched over a rectangular frame 4 via the support screen mesh. A metal film 5 called a metal mask is attached to the surface side facing the printed matter of the printing screen mesh 2 portion, that is, the so-called printing surface side. A printing pattern 7 having a printing opening pattern (not shown) is formed in a substantially central portion of the metal film 5, and a dummy pattern 8 is formed so as to surround the printing pattern 7. A dummy opening pattern (not shown) is formed in the metal film 5 portion of the dummy pattern 8, and the opening is blocked with a resin film (not shown) from the surface side where the squeegee scans during printing, that is, the so-called squeegee surface side. The size of the rectangular frame 4 is, for example, X450 mm × Y450 mm, and the width of the rectangular frame 4 is 30 mm. The printing screen mesh 2 is, for example, a calendar-processed stainless steel screen mesh, and the support screen mesh 3 is, for example, a polyester screen mesh. Both the printing screen mesh 2 and the support screen mesh 3 are, for example, bias-stretched. The metal film 5 is made of a nickel alloy by electrolytic plating. For example, the size is X290 mm × Y290 mm, the thickness is 13 μm, and the attaching plating 11 for fixing the metal film 5 to the printing screen mesh 2 is made of nickel by electrolytic plating, and the thickness is, for example, 1 μm.

[0014] FIG. 2 is a schematic front view of the printing pattern 7 and its peripheral portion seen from the printing surface side. In the printing pattern 7, six printing opening patterns 6 in the X direction and nine in the Y direction are arranged in a frame shape. Further, an outline 12 is formed so as to surround the printing pattern 7, and a dummy pattern 8 is formed outside the outline 12. The dummy pattern 8 has the same shape as the frame-shaped pattern of the printing pattern 7.

[0015] Figure 3(a) is a schematic enlarged view of the CC portion of Figure 2, Figure 3(b) is a schematic cross-sectional view of the CC portion of Figure 2, and Figure 3(c) is a schematic cross-sectional view of the boundary between the printing pattern 7 and the dummy pattern 8 in the DD portion of Figure 2. As shown in Figures 3(a) and 3(b), the suspend metal mask 1 having a dummy pattern of the present invention has a grid-like metal film 5 and a frame-shaped metal film 5 formed on the printing surface side of the peripheral portion of the frame-shaped printing opening pattern 6, and a resin film 10 is formed on the inner circumference of the frame-shaped metal film 5 from the squeegee surface side, with the metal film 5 protruding towards the printing surface side from the resin film 10 and formed at least near the printing opening pattern 6. Also, as shown in Figure 3(c), a resin film 10 is formed on the dummy pattern 8, and the dummy opening pattern 9 is closed by the resin film 10. As shown in Figures 3(a) and 3(b), the area occupied by the metal film 5 within the printing pattern 7 is very small. Therefore, unless a dummy pattern 8 is formed within a certain range surrounding the printing pattern 7, the difference in thickness between the metal film 5 near the center of the printing pattern 7 and the metal film 5 around the periphery of the printing pattern 7 becomes large. Figure 4(a) shows a schematic front view of the metal film 5 without a dummy pattern and a table showing the thickness of the metal film 5 within the printing pattern 7. Figure 4(b) shows a schematic front view of the metal film 5 within the printing pattern 7 when a dummy pattern 8 with a circumference 1.75 times the circumference of the printing pattern 7 is formed, and a table showing the thickness of the metal film 5 within the printing pattern 7. Figure 4(c) shows a schematic front view of the metal film 5 within the printing pattern 7 when a dummy pattern 8 with a circumference 2.45 times the circumference of the printing pattern 7 is formed, and a table showing the thickness of the metal film 5 within the printing pattern 7. Depending on the printing purpose, the outermost printing pattern 7 may be arranged flush with the surface, as shown in Figure 2, or, although not shown, the outermost printing pattern 7 may be arranged unevenly. Therefore, in this invention, the smallest rectangular shape that accommodates the printing pattern 7 is defined as the printing pattern external shape 13, and the perimeter of the smallest rectangular shape that accommodates the printing pattern 7 is defined as the perimeter of the printing pattern 7 external shape. There are no particular restrictions on the perimeter of the printing pattern external shape 13, but in order to obtain the high effect of this invention, it is desirable that the perimeter of the printing pattern external shape 13 be 236 mm or more. Furthermore, the area in which the dummy pattern 8 is formed is within a similar shape to the rectangular printable pattern external shape 13, and the similar shape is positioned so that it is substantially parallel to each of the opposing sides of the printable pattern external shape 13 and its center of gravity is at the same position as the center of gravity of the printable pattern external shape 13. In this embodiment, the printable pattern external shape 13 is a quadrilateral shape as shown by the dashed line in Figure 2, and the perimeter of the printable pattern external shape 13 is the sum of the lengths of sides a, b, c, and d. In this embodiment, the printable pattern external shape 13 is a square with sides a, b, c, and d each having a length of 75 mm, and the perimeter is the sum of the lengths of the sides, which is 300 mm. Therefore, when the printable pattern external shape 13 of this embodiment is scaled up by 1.75 times or 2.45 times, the external shape and perimeter become a square with sides of 131.25 mm and a perimeter of 525 mm when scaled up by 1.75 times, and a square with sides of 183.75 mm and a perimeter of 735 mm when scaled up by 2.45 times. Furthermore, it is desirable to form the dummy pattern 8 and the printing pattern 7 with an appropriate gap between them to prevent the printing opening pattern 6 near the dummy pattern 8 from being accidentally blocked by the resin film 10 when the dummy opening pattern 9 is blocked by the resin film 10. Therefore, an outline 12 as shown in Figure 2 is formed between the printing pattern 7 and the dummy opening pattern 9. Regarding the width W of the outline 12, if the gap between the printing pattern 7 and the dummy opening pattern 9 is too wide, the effect of the dummy pattern 8 will be diminished, so the width W of the outline 12 is preferably 200 μm or more and 2000 μm or less. In this embodiment, the width W of the outline 12 is 300 μm. There are no particular restrictions on the opening shape or spacing of the dummy pattern 8; any opening shape or spacing is acceptable. However, it is desirable that the opening ratio per unit area be close to the opening ratio per unit area when forming the metal film 5 in the printing pattern 7. For example, configuring the opening shape and spacing of the dummy pattern 8 to match the pattern opening shape and spacing of the printing pattern 7 is preferable because it satisfies the aforementioned conditions, facilitates the placement of the dummy pattern 8, and allows for the full effect of the dummy pattern 8 to be obtained. In this embodiment, the opening shape and spacing of the dummy pattern 8 are configured and arranged to match the frame-shaped pattern opening shape and spacing of the printing pattern 7.

[0016] In this example, the thickness of the metal film 5 within the printing pattern 7 was measured by measuring the thickness of each metal film 5 in a total of 54 frame-shaped patterns, arranged 6 in the X direction and 9 in the Y direction. Figures 4(a), 4(b), and 4(c) show the measured thicknesses of the 54 metal films 5 in the frame-shaped patterns, with the upper left frame-shaped pattern designated as (1,1) and the lower right frame-shaped pattern as (6,9). The maximum thickness is shown as max, the minimum thickness as min, the difference between max and min as range, the average of the 54 measurements as AVG, and the standard deviation of the 54 measurements as σ. All units are in μm. As is clear from the measurement results of the metal film 5 thickness in Figures 4(a), 4(b), and 4(c), the thickness of the metal film 5 without the dummy pattern 8 is thicker in the center and tends to become thinner towards the periphery. It can be confirmed that this tendency is suppressed by widening the area where the dummy pattern 8 is formed. The range, which is an indicator of the difference in the thickness of the metal film 5, is 5.8 μm without the dummy pattern 8, but becomes 3.8 μm when the dummy pattern 8 is arranged within a perimeter 1.75 times the outer shape of the printing pattern 13, and becomes 1.8 μm when the dummy pattern 8 is arranged within a perimeter 2.45 times the outer shape of the printing pattern 13, which is 4 μm smaller than without the dummy pattern 8. Furthermore, the standard deviation σ, which indicates the variation in the thickness of the metal film 5, was 1.39 without the dummy pattern 8, but was significantly smaller at 1.01 with 1.75 times the pattern and 0.46 with 2.45 times the pattern. This shows that widening the area where the dummy pattern 8 is formed reduces the difference in the thickness of the metal film 5. As described above, by forming the dummy pattern 8 within a range of 1.75 to 2.45 times the perimeter of the rectangular shape of the dummy pattern's external appearance, the uniformity of the thickness of the metal film 5 within the printing pattern 7 can be improved. Furthermore, since the dummy pattern 8 only needs to be formed within the rectangular shape having the above-mentioned circumference, the dummy pattern external shape 13 can have various shapes as long as it is within the rectangular shape. For example, it can have an external shape that is a cross-shaped shuriken extending from the center of the metal film 5 toward the four corners of the printing pattern 7, as shown in Figure 5.

[0017] Next, the method for manufacturing a suspended metal mask having the dummy pattern of the present invention will be described. Figures 6(a) to 6(j) are process diagrams illustrating the manufacturing method of the suspend metal mask having a dummy pattern according to the present invention, using the DD portion of Figure 2 as an example. As shown in Figure 6(a), a resist film 15 is formed on a conductive electroformed mold 14. While stainless steel materials such as SUS301 or SUS304 are commonly used for the conductive electroformed mold 14, any material that can be used as the electroformed mold 14 is acceptable. Methods for forming the resist film 15 include laminating a film-like photoresist, such as a dry film resist, using an existing laminator, or depositing a liquid resist onto the electroformed mold 14 using an existing liquid resist coating device such as a roll coater, spin coater, or curtain coater. Any method is acceptable as long as it allows for the formation of a resist film 15 of the desired thickness on the electroformed mold 14. Resists are broadly classified into negative-type and positive-type resists, and either type is acceptable. Here, a negative-type dry film resist is laminated onto the electroformed mold 14. The thickness of the resist film 15 is adjusted to match the thickness of the metal film 5.

[0018] As shown in Figure 6(b), the pattern is exposed using an exposure apparatus (not shown). The pattern includes at least a printing aperture pattern and a resin film formation aperture pattern within the printing pattern, and a dummy aperture pattern formed around the periphery of the printing pattern. Figure 6(b) shows a method in which a photomask 16 made of a material such as glass or film is brought into close contact with the resist film 15, and then ultraviolet light is irradiated onto the resist film 15 using a light source that generates ultraviolet light, such as an ultra-high pressure mercury lamp or a metal halide lamp (not shown). However, exposure may also be performed by directly drawing the pattern onto the resist film 15 without using a photomask 16, using a direct drawing apparatus with a semiconductor laser, LED or ultra-high pressure mercury lamp as the light source. Any exposure method can be used as long as the desired pattern can be exposed. Note that the mask and drawing pattern for contact exposure should be selected and used as either a negative pattern or a positive pattern according to the type of photoresist. Here, a negative type of resist is used in which the exposed area remains as a pattern resist film 17, so a negative pattern photomask is used for exposure.

[0019] As shown in Figure 6(c), the exposed resist film 15 is developed and dried to form a pattern resist film 17. The pattern resist film 17 has shapes such as a printing opening pattern 6 within the printing pattern 7, a resin film formation opening pattern 19 that will be closed with a resin film 10 in a later step, and a dummy opening pattern 9 that will surround the printing pattern 7. As shown in Figure 6(d), the electroformed mold 14 on which the pattern resist film 17 is formed is transferred to an electroforming bath (not shown), and electroplating is performed to form a metal film 5. There are no particular restrictions on the plating bath used for electroplating; for example, known plating baths such as nickel sulfamate baths or nickel sulfate baths may be used. There are no particular restrictions on the metal used, but nickel or nickel alloys such as nickel-cobalt alloys are preferred. In addition, the current density during electroplating should be 0.1 to 2.0 A / dm² to improve the uniformity of the plating amount as much as possible. 2 It is preferable to perform electroplating at a low current density. Here, electroplating of a nickel alloy is performed to form a first electroplating layer, which will become a metal film 5, on the surface of the electroformed matrix 14 that is not covered by the pattern resist film 17. In a later step, a second electroplating layer 11 is formed on this first electroplating layer 5 while it is in close contact with the printing screen mesh 2, thereby fixing the first electroplating layer 5 and the second electroplating layer 11 together. Therefore, it is preferable to make the thickness of the pattern resist film 17 and the thickness of the first electroplating layer 5 approximately uniform so that the printing screen mesh 2 can adhere easily. However, it is acceptable for the thickness of the pattern resist film 17 and the thickness of the first electroplating layer 5 to be different as long as the first electroplating layer 5 and the second electroplating layer 11 can be fixed together. In addition, polishing or the like may be performed to make the thickness of the pattern resist film 17 and the thickness of the first electroplating layer 5 approximately uniform.

[0020] As shown in Figure 6(e), a printing screen mesh 2, which has been stretched over a rectangular frame 4 (not shown) with appropriate tension beforehand, is brought into close contact with the side of the electroformed mold 14 where the pattern resist film 17 and the first electrolytic plating layer 5 have been formed, using a jig or the like (not shown). The printing screen mesh 2 stretched over the rectangular frame 4 used at this time may be a so-called "directly attached screen," in which the printing screen mesh 2 to be attached is stretched directly over the rectangular frame 4 with appropriate tension, or it may be a so-called "combination screen," in which the printing screen mesh 2 is stretched over the rectangular frame 4 with appropriate tension via a support screen mesh 3, as shown in Figure 1. If a directly attached screen is used, it becomes a directly attached suspended metal mask, and if a combination screen is used, it becomes a combination suspended metal mask. Here, the directly attached suspended metal mask and the combination suspended metal mask are collectively referred to as a suspended metal mask. In any case, the printing screen mesh 2 in the area where the first electroplating layer 5 is attached with the second electroplating layer 11 will use a conductive screen mesh such as a stainless steel screen mesh, a tungsten or tungsten alloy screen mesh, or a screen mesh made by nickel electroplating.

[0021] As shown in Figure 6(f), a conductive printing screen mesh 2 is brought into close contact with the side of the electroformed mold 14 where the pattern resist film 17 and the first electroplating layer 5 are formed, using a jig (not shown). Plating is then applied from the printing screen mesh 2 side to form a second electroplating layer 11, thereby fixing and integrating the first electroplating layer 5 and the second electroplating layer 11. The second electroplating layer 11 is also called bonded plating 11. The electroplating bath (not shown) used to form the second electroplating layer 11 is not particularly limited, as in Figure 6(d). The electroplating bath used in Figure 6(d) may be used, or a different type of electroplating bath may be used. Any metal can be used for electroplating, but nickel or nickel alloys such as nickel-cobalt alloys are preferred. Here, a different electroplating bath than the one used in Figure 6(d) was used to perform nickel electroplating and form the second electroplating layer 11.

[0022] As shown in Figure 6(g), the printing screen mesh 2 and the first electroplating layer 5, which are integrated in the second electroplating layer 11, are peeled off from the electroformed mold 14, and the unnecessary pattern resist film 17 is removed. At this point, the first electroplating layer 5 is formed on the printing surface side, that is, a suspended metal mask having a metal film 5 on the printing surface side is formed. However, the resin film formation opening pattern 19 in the printing pattern 7 and the dummy opening pattern 9 in the dummy pattern 8 remain open.

[0023] As shown in Figure 6(h), the photosensitive resin material 18 is applied from the squeegee side to the desired thickness using a known photosensitive resin coating method for screen printing, such as a bucket (not shown). The photosensitive resin material 18 used is not particularly limited as long as it is a photosensitive resin, but a photosensitive resin material for screen printing can be preferably used. At this time, the surface of the photosensitive resin material 18 may be smoothed (sometimes called flattening).

[0024] As shown in Figure 6(i), exposure is performed so as to close at least the closed portion of the resin film 10 in the printing pattern 7 and the closed portion of the resin film 10 in the dummy pattern 8. Any exposure method that can be used in the process shown in Figure 6(b) may be used. At this time, as shown in Figure 6(i), it is preferable that the outer periphery of the closed portion of the resin film 10 in the printing pattern 7 is formed without misalignment with the position of the frame-shaped pattern of the metal film 5 formed by the first electroplating layer. However, as shown in Figures 3(b) and 3(c), as long as the resin film 10 extends beyond the frame-shaped pattern of the metal film 5 and does not overlap the printing opening pattern 6, and at least the closed portion is closed by the resin film 10, it is acceptable even if the position is misaligned with the frame-shaped pattern of the metal film 5, or even if the closed range of the resin film 10 is smaller than the outer periphery of the frame-shaped pattern of the metal film 5.

[0025] As shown in Figure 6(j), by developing the photosensitive resin material and removing the excess photosensitive resin material, a suspend metal mask 1 with a dummy pattern can be obtained, in which the first layer is formed of a resin film 10, the second layer is formed of a metal film 5, the second layer of metal film 5 is formed at least near the printing opening pattern 6 with the metal film 5 protruding towards the printing surface side from the first layer of resin film 10, and the dummy opening pattern 9 is closed off by the first layer of resin film 10 so as to surround the printing pattern 7. If necessary, functional materials such as liquid repellency or hydrophilicity may be imparted to the obtained suspend metal mask 1 with a dummy pattern by an appropriate method, or the resin film and metal film may be formed to an appropriate surface roughness. [Industrial applicability]

[0026] This invention can be used in various screen printing fields where suppression of printing bleeding is required, as well as in suspended metal masks having a large pattern aperture area, or so-called negative patterns. [Explanation of symbols]

[0027] 1. Suspended metal mask with dummy pattern 2. Screen mesh for printing 3. Support screen mesh 4. Rectangular frame 5. Metal film (first electrolytic plating layer) 6. Printed aperture pattern 7. Printable Pattern 8..Dummy Pattern 9..Dummy opening pattern 10. Resin film 11. Adhesive plating (second electrolytic plating layer) 12..Outline 13. Printable pattern appearance 14. Electroformed mold 15. Resist film 16.. Photomask 17. Pattern resist film 18...Photosensitive resin material 19. Opening pattern for resin film formation

Claims

1. A suspend metal mask having a dummy pattern, wherein the first layer is formed of a resin film and the second layer is formed of a metal film, the second layer of metal film is formed at least near the printing opening pattern with the second layer of metal film protruding towards the printing surface side than the first layer of resin film, the second layer of metal film forms a dummy opening pattern so as to surround the printing pattern, and the dummy opening pattern is closed by the first layer of resin film to form a dummy pattern.

2. A suspend metal mask having a dummy pattern according to claim 1, characterized in that, when the smallest rectangular shape that can accommodate the printing pattern is defined as the external shape of the printing pattern, the dummy pattern is formed outside the external shape of the printing pattern so as to surround the printing pattern, and is formed within a rectangular shape that is larger than the external shape of the printing pattern and similar in shape to the external shape of the printing pattern.

3. The suspend metal mask having a dummy pattern according to claim 2, characterized in that the dummy pattern is formed outside the external shape of the printable pattern so as to surround the printable pattern, and is formed within a rectangular shape similar to the external shape of the printable pattern, having a perimeter of 1.75 times or more and 2.45 times or less the perimeter of the external shape of the printable pattern.

4. A method for manufacturing a suspended metal mask obtained by plating a metal mask and a screen mesh, comprising the steps of: forming a resist formed as a printable opening pattern, a resist formed as a resin film formation opening pattern, and a resist for a dummy opening pattern on a matrix for electroplating; manufacturing a metal mask by electroplating using a matrix for electroplating on which the printable opening pattern, the resin film formation opening pattern, and the dummy opening pattern are formed from resist; integrally joining the metal mask and the screen mesh by electroplating; forming a printable opening pattern, a resin film formation opening pattern, and a dummy opening pattern by peeling the matrix for electroplating and the resist from the metal mask; and filling at least the resin film formation opening pattern and the dummy opening pattern with resin from the squeegee side to close the resin film formation opening pattern and the dummy opening pattern portions, thereby enabling the transfer of a printed material from the printable opening pattern to a workpiece.

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