JP3939785B2 - Electroformed thin metal plate and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes, for example, printing metal masks, IC lead frames, inkjet nozzles, vapor deposition masks, sheet coils, thin planar antennas, rotary encoders, and the like that are preferably used for screen printing of IC and LSI printed wiring, etc. The present invention relates to an electroformed thin metal plate similar to these and a manufacturing method thereof.
[0002]
[Prior art]
When manufacturing this type of electroformed thin metal plate, for example, a printing metal mask, by electroforming, first, as shown in FIGS. After patterning the photoresist 21, an electrodeposition layer 22 is electrodeposited on the surface of the master mold 20 that is not covered with the photoresist 21, and then the surface of the electrodeposition layer 22 is polished, and then the matrix 20 is electroplated. The metal layer for printing which peeled the adhesion layer 22 and has the opening part 1 of the desired pattern was obtained.
[0003]
[Problems to be solved by the invention]
However, in the conventional metal mask manufacturing method described above, the line width between the openings 1 and 1 of the mask substrate 2 is regulated by the photoresist 21, so that a precise fine pattern with relatively excellent reproducibility can be obtained. The master die 20 is required for each piece, which is expensive. Further, the precision of the fine opening pattern depends on the development performance or thickness of the photoresist 21, and a portion of the developed photoresist 21 is not exposed as shown in the enlarged view of FIG. In the case where the adhesive force is insufficient, chipping may occur due to peeling from the mother die 20, or defects may occur due to generation of pits 24. Furthermore, during patterning with a photoresist, the fixing property of the photoresist is also affected by the room temperature, exposure time, development conditions, and the like, so it has been necessary to strictly manage them.
[0004]
An object of the present invention is to solve such problems, and is to provide an electroformed thin metal plate that can ensure strength while being thin. Another object of the present invention is to provide a method for producing an electroformed thin metal plate that can be produced easily and accurately at low cost by enabling repeated use of the original plate. In offer.
[0005]
[Means for Solving the Problems]
In the electroformed thin metal plate of the present invention, an opening 1 having a desired pattern is formed in a thin metal plate main body 2 made of a conductive material, and a region in the opening 1 has a plurality of mesh lines 1a. Ribs 3 which are divided into small openings and are continuous with a fine pitch on one side of the thin metal plate body 2 including the mesh line 1a are formed integrally with the thin metal plate body 2 and the mesh line 1a. One rib 3 is formed on each of the mesh lines 1 a provided in the opening 1, and the interval between the mesh lines 1 a is formed on the thin metal plate body 2 other than the opening 1. It is characterized by being set to be larger than the adjacent interval p of the ribs 3 .
[0006]
In the present invention, when the electroformed thin metal plate having the above-described structure is manufactured, a fine groove 6 corresponding to the pattern of the rib 3 is formed on the surface of the non-conductive original plate 4 including the portion to be the opening 1. Forming a mesh at a fine pitch, forming a conductive plating base 8 only in the groove 6 of the original plate 4, and using the plating base 8 in the groove 6 of the original plate 4 as an electrode. The cast metal is grown to form the mesh-like ribs 3 with a fine pitch in the grooves 6 of the original plate 4, and the mesh line 1 a is not connected to the portion of the surface of the original plate 4 that becomes the opening 1. In this way, the mesh line 1a is formed integrally with the rib 3, and the thin metal plate body 2 that connects the ribs 3 is formed on the surface of the original plate 4 other than the opening 1, and the mesh line 1a. The thin metal plate main body 2 including And wherein the door.
[0007]
[Action]
If the continuous ribs 3 are formed on one surface of the thin metal plate main body 2 at a minute pitch, a thin metal plate having an appropriate strength, particularly a bending strength, can be obtained even if it is thin.
[0008]
When manufacturing a thin metal plate, the original plate 4 after peeling the thin metal plate main body 2 can be reused. Without using a photoresist such as a conventional metal mask by electroforming as described above, the base plate 4 having the fine grooves 6 or the recesses 9 group is used, and the plating base 8 is formed in the grooves 6 or the recesses 9 to make the electrolysis. Because it is cast, regardless of the developability of photoresist, thickness, and condition management during patterning, there is no decrease in the adhesion between the matrix and the photoresist, and pits are not generated especially at the periphery of the opening 2, and the pattern Since the formed original plate can be reused repeatedly, a highly precise and fine aperture pattern with excellent reproducibility in dimensional accuracy and the like is obtained.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
( Reference example)
FIGS. 1 to 3 show reference examples when the present invention is applied to a printing metal mask. FIG. 1 shows a part of a metal mask for printing, which is a thin metal plate body having a desired pattern of openings 1, that is, a continuous rib 3 formed at a minute pitch on the printing surface 2a side of a mask substrate 2. ing. The rib 3 needs to be formed continuously and with a conductive material in order to serve as an electrode (cathode) during electroforming of the metal mask. For example, the thickness t of the mask substrate 2 is 50 μm. The opening width w of the opening 1 varies depending on the shape and size of the pattern, but is, for example, 30 to 70 μm. The rib 3 is formed in a mesh shape, the protruding height h of the rib 3 from the printing surface 2 a of the mask substrate 2 is 0.5 to 2 μm, the width q of the rib 3 is 5 to 10 μm, and the rib 3 and the rib 3 The interval p is 5 to 10 μm.
[0010]
FIGS. 2A to 2G show process diagrams for obtaining an electroformed product of such a printing metal mask. First, as shown in FIG. 2 (A), a chrome thin film is uniformly formed on one surface side of the glass original plate 4 by a method such as sputtering, and an EB drawing or pattern is formed on the surface of the chromium thin film of the original plate 4. A chrome mask 5 having a pattern in which the chrome thin film is removed corresponding to the pattern of the rib 3 of the printing metal mask is created by a generator drawing or the like except for the portion corresponding to the pattern of the opening 1. Next, as shown in FIG. 2 (B), the portion of the surface of the original plate 4 not covered with the chromium mask 5 is corroded with a glass corrosive solution containing hydrofluoric acid, and then the chromium film is removed to remove the chromium film. As shown in FIG. 3 and FIG. 3, a fine mesh-like groove 6 corresponding to the pattern of the rib 3 is formed in a portion excluding the portion to be the opening 1 of the printing metal mask. For example, the opening width a of the groove 6 is 10 μm, the interval b between the groove 6 and the groove 6 is 10 μm, and the depth d of the groove 6 is 0.7 μm. The portion corresponding to the opening 1 is a flat portion where the groove 6 does not exist, depending on the shape and size of the pattern.
Next, as shown in FIG. 2D, a silver thin film 7 is formed on the surface of the original plate 4 and in the groove 6 by chemical plating such as silver mirror reaction. Next, by removing only the silver thin film 7 on the surface of the original plate 4 with a sponge soaked with water, a conductive plating base 8 made of a silver thin film is formed only in the groove 6 as shown in FIG. To do.
[0011]
Next, in a normal nickel sulfamate bath, using the plating base 8 in the continuous groove 6 as an electrode, nickel is grown from the plating base 8 to form the groove 6 of the original plate 4 as shown in FIG. The inner plating base 8 is electroformed to a height exceeding the depth of the groove 6, and the electroformed nickel is allowed to continue to grow after exceeding the depth of the groove 6. The electrocast nickels that exceed the above are continuously connected to form the rib 3 of the metal mask for printing in the groove 6, and the mask substrate 2 that connects the ribs 3 on the surface of the original plate 4, and the opening 1 Form. Since the non-conductive original plate 4 having the fine grooves 6 is used and the plating base 8 is formed in the grooves 6, the ribs 3 and the mask substrate 2 are formed by electrodeposition. Compared to the electroforming method used, a printing metal mask having a precision fine pattern with extremely high dimensional accuracy can be obtained. In particular, the peripheral portion of the opening 1 has a high-precision pattern without pits and chips without being affected by the adhesion state of the resist and the development performance as compared with the case where electroforming is performed by patterning a photoresist. Could be formed.
An example of the composition and plating conditions of a nickel sulfamate bath is shown.
Nickel sulfamate 450g / l
Nickel chloride 40g / l
Boric acid 30g / l
Bath temperature 50 ° C
pH 4.0-4.5
Current density 5A / dm ²
[0012]
Next, the mask substrate 2 is peeled off from the original plate 4 together with the ribs 3 (FIG. 2G). At that time, since the adhesive base with the original plate 4 is weak, the chemical-plated silver-plated plating base 8 is peeled off from the original plate 4 while adhering to the rib 3 side. After peeling, the plating base 8 attached to the rib 3 can be removed from the rib 3 by anodic electrolysis with sodium cyanide. By removing the plating base 8, it is possible to obtain the rib 3 having a protruding height that is lower by the thickness of the plating base 8. However, it is not always necessary to remove the plating base 8, and it can be used while being attached to the rib 3.
[0013]
Since the printing metal mask thus obtained has the continuous ribs 3 formed on the printing surface side of the mask substrate 2 at a minute pitch, the thin metal mask can ensure the bending strength. Also, the metal mask for printing is stretched on the mask frame during screen printing and then placed on a printed material such as a printed circuit board (printing object), and the cream solder is moved to the opening 1 of the metal mask by moving the squeegee. It is filled and transferred to the substrate. At this time, since the rib 3 is formed on the printing surface of the metal mask, it is in close contact with the substrate via the rib 3, so that it can be easily separated from the substrate. It is excellent in releasability, and can easily stick to the mask frame and can be firmly framed. Furthermore, the particle size of conductive paste such as cream solder or tungsten paste to be printed is about 5 to 6 μm, but the rib 3 is formed to a very small height of about 0.5 to 2 μm with respect to the mask substrate 2. Therefore, there is no risk of bleeding due to the conductive paste wrapping around, and high-precision printing is possible.
[0014]
(First Embodiment)
4 to 7 show a first embodiment of the present invention. This embodiment is the same as the reference example except that each opening 1 is formed in a mesh shape. That is, the printing metal mask of this embodiment has a mesh-like rib 3 formed on the printing surface side of the mesh substrate 1 and the mesh line 1a in the opening 1, as shown in part in FIG. The mesh of 1a is formed larger than the mesh size of the rib 3. For example, when screen printing is performed using this metal mask, a conductive paste such as ink or cream solder is discharged from the mesh-shaped opening 1. When the opening 1 is formed in a mesh shape, even when the opening 1 is formed with a large opening width such as a long hole, the mask substrate 2 may be covered with the opening 1 due to the reinforcing function by the mesh line 1a. In addition, the strength can be ensured, the handling can be easily performed, and high-precision printing is possible. Further, as shown in FIG. 7, the opening 1 can be formed in a ring shape having a land portion independent of the mask substrate 2 in the center of the opening 1. Further, as a mesh-integrated metal mask, the amount of printing of the conductive paste or the like through the opening 1 can be regulated by the mesh line 1a, and high-precision printing can be performed.
[0015]
FIGS. 5A to 5G are process diagrams for obtaining such a metal mask electroformed product. As shown in FIG. 5C and FIG. 6, a glass original plate 4 in which grooves 6 having fine groove widths corresponding to the patterns of the ribs 3 and the openings 1 are formed. As a manufacturing method of the original plate 4, as in the case of the reference example, EB drawing or the like is used (FIGS. 5A and 5B). The opening width a of the groove 6, the distance b between the grooves 6 and 6, and the depth d of the groove 6 are the same as those in the reference example. In this embodiment, the opening width w of the opening 1 is a pattern set to 0.5 to 5 mm. The interval between the mesh line 1a and the mesh line 1a of the opening 1 is larger than the interval b of the groove 6 and is, for example, 50 to 500 μm. Next, as shown in FIG. 5E, a conductive plating base 8 is formed in the mesh-like grooves 6 of the original plate 4. As in the case of the reference example, the silver thin film 7 formed by chemical plating as shown in FIG. 5D is removed only with the sponge, and the plating base 8 made of the silver thin film 7 is formed only in the groove 6. Form.
[0016]
Next, in a normal nickel sulfamate bath, the mesh-like rib 3 and the mesh-like opening 1 are formed by electroforming the plating base 8 in the groove 6 of the original plate 4 as shown in FIG. 5 (F). A mask substrate 2 having electrodeposition is formed. At that time, the amount of metal electrodeposited per unit area is substantially constant, and the mesh interval of the mesh line 1a of the opening 1 is set several times to several tens of times larger than the interval of the ribs 3. By simply growing the mesh line 1a of the opening 1 into a mushroom cross section with ribs 3 on the printing surface side, the mesh line 1a is not connected to each other, and the opening 1 can be formed in a mesh shape. In this case, the composition and plating conditions of the nickel sulfamate bath are the same as in the reference example. Finally, as shown in FIG. 5G, the mask substrate 2 is peeled from the original plate 4 together with the ribs 3 and the mesh lines 1a.
[0017]
(Other embodiments)
Forms a silver thin film 7 on the surface of the master plate 4 with a chemical plating of silver mirror reaction and the like in forming a plating base 8 for the actual施例like described above, palladium by sputtering on the surface of the master plate 4 instead of this, gold Alternatively, a conductive thin film such as silver may be formed. In this case, by polishing the surface of the original plate 4, only the conductive thin film on the surface of the original plate 4 except for the inside of the groove 6 is removed, and the plating base 8 is formed leaving the conductive thin film only in the groove 6. . As the electroformed metal grown from the plating base 8, in addition to nickel, various nickel alloys such as a nickel-codolto alloy and copper can be considered. In addition to glass, the original plate 4 can also be formed of a nonconductive material such as ceramic or synthetic resin.
[0018]
Although the grooves 6 in the original plate 4 for the actual施例like described above are formed in the vertical line and the mesh-like obtained by cross horizontal lines, in addition to this, the vertical lines only, or may be only horizontal. However, in the case where the grooves 6 are only the vertical lines or only the horizontal lines, it is necessary to form a conduction groove that crosses the grooves 6 and 6 formed in the original plate 4 in order to achieve electrical conduction during electroforming. . In addition, instead of attaching the groove 6 to the original plate 4 except for the portion that becomes the opening 1, a plurality of groups of minute recesses 9 may be attached in a chain. That is, after forming a photoresist film 10 at a location corresponding to the pattern of the opening 1 on the surface of the original plate 4 as in the second embodiment shown in FIG. 8, shot blast is sprayed on the surface of the original plate 4, By forming the surface of the original plate 4 other than the portion covered with the photoresist film 10 into a ground glass shape, a group of minute recesses 9 are formed in a chain on the entire surface other than the photoresist film 10 corresponding to the opening 1. You may do. Alternatively, the portion corresponding to the pattern of the opening 1 on the surface of the original plate 4 is masked with chrome or the like, and then etched with hydrofluoric acid or the like to be processed into a rough surface with irregular irregularities. 9 may be formed in a chain form on the entire surface other than the photoresist film 10 corresponding to. The photoresist film 10 and the masking film such as chrome are then removed to expose a portion corresponding to the opening 1. The formation of a plating base 8 made of a conductive thin film of silver or the like in a large number of chain-like minute recesses 9 formed in this way, the growth of electroforming from the plating base 8, etc. This is exactly the same as the case of the groove 6 in the embodiment.
[0019]
In addition to the above-described printing metal mask, the electroformed thin metal plate can be similarly applied to an IC lead frame, an inkjet nozzle, a vapor deposition mask, a sheet coil, a thin flat antenna, a rotary encoder, and the like. In that case, an ultra-thin metal plate product having a total metal plate thickness including the protrusion height h (0.5 to 1 μm) of the rib 3 of about 3 μm can be realized.
[0020]
【The invention's effect】
According to the electroformed thin metal plate of the present invention, the continuous ribs 3 are integrally formed on one surface of the thin metal plate main body 2 at a minute pitch, so that the thin metal having openings 1 having a desired pattern. Also suitable for electroformed products such as metal masks for printing, IC lead frames, inkjet nozzles, masks for vapor deposition, sheet coils, thin planar antennas, rotary encoders, etc. .
[0021]
According to the method for producing an electroformed thin metal plate of the present invention, the original plate 4 having a fine groove 6 or a concave portion 9 is used in a portion other than the portion to be the opening 1 of the thin metal plate, and the groove 6 is used. Alternatively, after the plating base 8 is formed in the recess 9, the rib 3 and the thin metal plate body 2 are electrodeposited by growing from the plating base 8, so that compared with the conventional electroforming method using a photoresist. Thus, a thin metal plate having a precise fine pattern with extremely high dimensional accuracy can be obtained. In particular, the peripheral portion of the opening 1 has a high-precision pattern without pits and chips without being affected by the adhesion state of the resist and the development performance as compared with the case where electroforming is performed by patterning a photoresist. Can be formed.
[0022]
Further, after electroforming the thin metal plate body 2, it is conceivable to form the rib 3 on one side thereof by etching or the like. However, in this case, the hole wall surface of the opening 1 formed with high precision is roughened by the etching solution. However, it is possible to easily obtain a highly accurate thin metal plate without such problems.
Moreover, the original plate 4 can be used repeatedly, and the manufacturing cost can be reduced. By using the same original plate 4, a stable thin metal plate with little variation can be obtained as long as the electroforming bath is strictly controlled.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a part of a metal mask for printing of a reference example in a cutaway manner.
FIG. 2 is a manufacturing process diagram of a printing metal mask of a reference example.
FIG. 3 is a perspective view of a part of an original plate used in a reference example.
FIG. 4 is a perspective view showing a part of the metal mask for printing according to the first embodiment in a cutaway manner.
FIG. 5 is a manufacturing process diagram of the printing metal mask of the first embodiment.
FIG. 6 is a perspective view of a part of an original plate used in the first embodiment.
7 is an enlarged plan view of a part of another example of the opening of the printing metal mask according to the first embodiment as viewed from the printing surface side. FIG.
FIG. 8 is a partial perspective view showing a surface state of an original plate according to a second embodiment.
FIG. 9 is a manufacturing process diagram of a conventional electroformed product.
[Explanation of symbols]
1 Opening 2 Thin metal plate body (for example, mask substrate)
3 Rib 4 Original plate 6 Groove 8 Plating substrate 9 Minute recess

Claims (2)

An opening (1) having a desired pattern is formed in the thin metal plate body (2) made of a conductive material,
The region in the opening (1) is divided into a plurality of small opening regions by a mesh line (1a),
On one side of the thin metal plate body (2) including the mesh line (1a), a rib (3) continuous in a mesh pattern at a fine pitch is integrated with the thin metal plate body (2) and the mesh line (1a). Formed,
A rib ( 3 ) is formed on each of the mesh lines (1 a) provided in the opening (1), and the interval between the mesh lines (1 a) is a thin metal other than the opening (1). An electroformed thin metal plate, which is set to be larger than an interval (p) between adjacent ribs (3) formed on the plate body (2). A method for producing an electroformed thin metal plate according to claim 1,
Forming a fine groove (6) corresponding to the pattern of the rib (3) in a mesh pattern at a fine pitch on the surface of the non-conductive original plate (4) including a portion to be the opening (1); ,
Forming a conductive plating base (8) only in the groove (6) of the original plate (4);
An electroformed metal is grown using the plating base (8) in the groove (6) of the original plate (4) as an electrode, and a mesh-like rib (3) is formed in the groove (6) of the original plate (4) with a fine pitch. In addition, the mesh line (1a) is formed integrally with the rib (3) so that the mesh line (1a) is not connected to the portion of the surface of the original plate (4) to be the opening (1). And forming a thin metal plate body (2) connecting the ribs (3) to the surface of the original plate (4) other than the opening (1),
A method for producing an electroformed thin metal plate comprising a step of peeling a thin metal plate body (2) including a mesh line (1a) together with a rib (3) from an original plate (4).

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