JP3865085B2 - Manufacturing method of electroformed product - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention can be applied, for example, to screen printing of IC and LSI printed wiring, solder cream printing of BGA, CSP, etc., metal mask used for phosphor printing for PDP, etc. The present invention relates to a manufacturing method of a product.
[0002]
[Prior art]
For example, when a metal mask for printing is manufactured by electroforming, first, as shown in FIG. 3A, a photoresist 6 is brought into close contact with the surface of a mother die 3 made of a conductive material such as stainless steel. As shown in FIG. 3 (C), a pattern mask 20 such as a film or glass plate having a desired printing pattern is brought into close contact with the photoresist 6 as shown in FIG. 3 (B), and exposure, development, and drying are performed. The photoresist film 7 having a desired pattern is formed by patterning as shown in FIG. Next, as shown in FIG. 3D, the electrodeposition metal layer 9 is electrodeposited on the surface of the matrix 3 that is not covered with the photoresist film 7 by electroforming, and finally the electrodeposition metal layer 9 and After polishing the surface of the photoresist film 7, the electrodeposited metal layer 9 was peeled off from the mother die 3 as shown in FIG. 3E to obtain a printing metal mask 1 having openings 2 having a desired pattern.
[0003]
[Problems to be solved by the invention]
In the conventional electroforming method described above, since the line width between the openings 2 and 2 of the metal mask 1 is regulated by the photoresist film 7, a precise electroformed product that is relatively excellent in reproducibility compared with etching or the like is obtained. can get. However, although the metal mold 3 made of a metal material such as stainless steel is used, the metal metal mold 3 often has voids or scratches. The adhesion failure with the resist film 7 was likely to occur. In addition, dust or the like easily enters and adheres between the pattern mask 20 and the photoresist 6, and this dust adhesion sometimes causes exposure failure. When the exposure, the exponential absorption of light rays is different between the surface side of the photoresist 6 and the side facing the mother die 3, and the light rays hardly reach the side facing the mother die 3, so that underexposure is likely to occur. As a result, the photoresist film 7 has insufficient adhesion to the mother die 3 and is peeled off from the mother die 3 to cause chipping or pits. This causes a reduction in resolution. Such chipping of the photoresist film 7 and the occurrence of defective pits become more noticeable as the photoresist 6 is relatively thick and has a low light transmittance.
[0004]
An object of the present invention is to solve such problems, and is to provide a method for producing an electroformed product with improved accuracy by improving the adhesion and resolution of a photoresist to a mother die during the production process. .
[0005]
[Means for Solving the Problems]
In the method for producing an electroformed product according to the present invention, a non-conductive material having translucency, such as glass or a resin film, is prepared as the matrix 3. First, the conductive thin film 4 is formed on the surface of the matrix 3. Next, the conductive thin film 4 is patterned into a desired pattern including the conductive mask 5a and the openings 5b. Next, a negative type photoresist 6 is closely polymerized on the surface of the base 3 not covered with the conductive mask 5a and the surface of the conductive mask 5a. Next, exposure is performed by irradiating ultraviolet rays, electron beams, or the like from the back side of the mother die 3, and development processing is performed to form a photoresist film 7 on the surface of the mother die 3 that is not covered with the conductive mask 5 a. Next, an electrodeposition metal layer 9 is electrodeposited on the surface of the conductive mask 5a by electroforming. The photoresist film 7 is removed while the electrodeposited metal layer 9 is attached to the matrix 3. In a state where the metal mesh 10 is pressed onto the electrodeposited metal layer 9, plating 11 is applied. Finally, the electrodeposited metal layer 9 integrated with the mesh 10 is removed from the matrix 3 by plating 11 .
[0006]
[Action]
When patterning the photoresist film 7, the conductive mask 5 a is patterned on the surface, and exposure is performed by irradiating ultraviolet rays, electron beams, or the like from the back side of the matrix 3 in which the negative type photoresist 6 is closely polymerized. Therefore, the hardening of the photoresist 6 proceeds from the mother die 3 side. Accordingly, the adhesion between the mother die 3 and the photoresist film 7 does not deteriorate, chipping, pits, etc. occur, and the conductive mask 5a and the photoresist film 7 are securely in contact with each other. To obtain high precision electroformed products.
[0007]
When patterning the photoresist film 7, without using the pattern mask 20 as in the conventional electroforming method described above, the back side of the mother die 3 is utilized by using the conductive mask 5 a that functions as a base for plating. Therefore, the problem of dust adhesion that causes the exposure failure of the conventional photoresist 6 described above can be solved.
[0008]
Since the mother die 3 made of glass, resin film or the like has no void like a metal mother die, the adhesion with the photoresist 6 is improved. Further, when the electrodeposited metal layer 9 is peeled off, the conductive mask 5a remains on the mother die 3 side. Therefore, when the mother die 3 having excellent rigidity such as a glass plate is used, the pattern mask is exposed again on the mother die 3. The mother die 3 can be repeatedly used by using the conductive mask 5a as it is without going through development or the like, and the workability is excellent.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
( Comparative example)
Figure 1 shows a comparison example of the application of the product manufacturing method for printing metal mask electroforming. As shown in FIG. 1G, the printing metal mask 1 has openings 2 having a desired pattern, and the thickness thereof is, for example, about 20 to 30 μm.
[0010]
In order to manufacture such a printing metal mask 1, first, as shown in FIG. 1A, it is made of a non-conductive material having translucency such as a transparent resin film or sheet such as glass or polyester or polyimide film. A conductive thin film 4 is formed on the surface of the mother die 3 by sputtering chromium. The film thickness is, for example, about 1500 to 3000 mm. If it is thinner than that, it is likely to cause a conductive failure. Next, a positive type resist thin film is formed on the conductive thin film 4, and the resist thin film is directly drawn in a desired pattern by EB drawing (electron beam) or PG drawing (pattern generator), and the exposed chrome surface is formed. The conductive mask 5a having a desired pattern, in which the conductive thin film 4 in the portion corresponding to the opening 2 of the printing metal mask 1 is removed and the opening 5b is formed by etching away, as shown in FIG. The patterning forming.
[0011]
Next, as shown in FIG. 1C, a negative type photoresist 6 is coated on the surface of the matrix 3 not covered with the conductive mask 5a and the surface of the conductive mask 5a. The thickness of the photoresist 6 is about 20 to 30 μm. Since a transparent resin film such as glass or a polyimide film is used for the mother die 3, there is no concern about a void like a metal mother die, and the photoresist 6 can be coated in a close contact state.
[0012]
Next, as shown in FIG. 1 (D), exposure is performed by irradiating ultraviolet rays from the back side of the mother die 3 with an ultraviolet lamp, and development and drying are performed, whereby the conductivity of the mother die 3 is obtained as shown in FIG. 1 (E). Formed on the surface corresponding to the opening 5b not covered with the mask 5a is a photoresist film 7 having a pattern from which the photoresist 6 is removed except for the portion corresponding to the pattern of the opening 2 of the printing metal mask 1 To do. At this time, since exposure is performed by irradiating ultraviolet rays from the back side of the mother die 3, the ultraviolet curing of the photoresist 6 proceeds from the mother die 3 side so that it can be brought into close contact with the mother die 3 and there is no pit or chipping. A highly accurate photoresist film 7 could be obtained. Further, the photoresist film 7 could be reliably adhered to the conductive mask 5a.
[0013]
Next, in an ordinary nickel sulfamate bath, nickel is grown from the conductive mask 5a and electroformed to the height of the photoresist film 7 as shown in FIG. To do.
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
[0014]
After electroforming, the electrodeposition metal layer 9 is peeled off from the mother die 3 as shown in FIG. 1G, whereby the printing metal mask 1 having the opening 2 is obtained. At that time, the conductive mask 5a has strong adhesion to the mother die 3 side and remains as it is on the mother die 3 side by peeling. Therefore, the mother die 3 on which the conductive mask 5a is formed can be used repeatedly. is there.
[0015]
(Real施例)
Figure 2 shows the real施例of the present invention. In this embodiment, a manufacturing method when applied to a mesh-integrated metal mask for screen printing will be described. When manufacturing this mesh-integrated metal mask for screen printing, first, a metal mask 1 having openings 2 having a desired pattern is electroformed by the same method as in the comparative example. 1 (the electrodeposited metal layer 9) is removed from the matrix 3 while the photoresist film 7 is removed. After this removal, a metal mesh 10 is placed on the electrodeposited metal layer 9 as shown in FIG. In the pressed state, a plating 11 is applied as shown in FIG. 2B, and the mesh 10 and the electrodeposited metal layer 9 are joined and integrated by the plating 11 to obtain a mesh-integrated metal mask for screen printing.
[0016]
It should be noted here that since the mother die 3 is made of a non-conductive material, the plating 11 is removed after removing only the photoresist film 7 with the metal mask 1 (electrodeposited metal layer 9) being attached to the mother die 3. It is a point that can be done. In the conventional electrocasting method of the mesh mask for screen printing metal mask, since the mother die 3 is made of metal, electroforming as shown in FIG. 4A is performed so that the electroformed metal does not grow from the surface of the mother die 3. Then, after polishing the surface, it is necessary to press the mesh 10 while leaving the photoresist film 7 and to perform plating 11. However, since the photoresist film 7 has less hardness than the electrodeposited metal layer 9, the surface polishing is performed. As a result, the surface of the photoresist film 7 is abraded from the surface of the electrodeposited metal layer 9 and a step 12 (enlarged view of FIG. 4B) is formed between the two surfaces. The body 13 is formed. When the eaves 13 are present, when printing is performed using this mesh-integrated screen printing metal mask, a resistor such as a carbon base or a conductive paste such as tungsten paste / cream solder is opened (see FIG. 4). It becomes an obstacle to discharging from the (B) opening formed by removing the photoresist film 7) and causes printing failure. In order to eliminate this drawback, in this embodiment, since the plating 11 is performed after removing the photoresist film 7, the plating 11 grows on the entire side surface 9 a of the electrodeposited metal layer 9 as shown in FIG. As shown in FIG. 4B, a defective eaves-like body 13 cannot be formed.
[0017]
In the above embodiment, chromium is used as the conductive thin film 4, but a conductive material such as nickel, tungsten, or tantalum can be used instead. Further, as a means for forming the conductive thin film 4 on the surface of the mother die 3, it may be formed by dry plating such as vacuum deposition or ion plating other than sputtering.
As the electroformed metal grown from the conductive mask 5a, various nickel alloys such as nickel-cobalt alloy and copper can be considered in addition to nickel.
Further, the method of patterning the conductive thin film 4 is not limited to the direct drawing by the EB or PG drawing, but a method of patterning by exposing and developing by irradiating with ultraviolet rays after placing a pattern film on a negative type resist. But you can.
[0018]
【The invention's effect】
According to the method for producing an electroformed product of the present invention, the conductive mask 5a is patterned on the surface of the mother mold 3 having translucency, and the photoresist 6 is closely polymerized. Then, the photoresist film 7 is formed by exposure by ultraviolet irradiation and development. Accordingly, the UV curing of the photoresist 6 proceeds from the side of the mother die 3, so that the adhesion with the mother die 3 is good, there is no occurrence of chipping or pits, and the conductive mask 5a and the photoresist film 7 are securely attached. Therefore, a highly accurate electroformed product having excellent resolution and excellent reproducibility in dimensional accuracy and the like is obtained. By forming the photoresist film 7 by patterning using the conductive mask 5a that exhibits the function of the base for plating, it is not necessary to use the pattern mask 20 like the conventional electroforming described above. This is advantageous because it can solve the problem of dust adhesion that causes the exposure failure. Further, since the mother mold 3 is made of glass or resin film having no void like a metal mother mold, the adhesion to the photoresist 6 can be improved in this respect as well. Further, since the conductive mask 5a can be left as it is on the mother die 3 side at the time of peeling, the mother die 3 can be used repeatedly, and the efficiency of the work process can be improved. Since the plating 11 is performed after the photoresist film 7 is removed, the eaves-like body 13 that causes printing failure cannot be formed.
[Brief description of the drawings]
FIG. 1 is a manufacturing process diagram of a printing metal mask of a comparative example.
FIG. 2 is a manufacturing process diagram of the printing metal mask of the real施例.
FIG. 3 is a manufacturing process diagram of a conventional electroformed product.
FIG. 4 is a manufacturing process diagram of another conventional electroformed product.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal mask 2 Opening part 3 Matrix 4 Conductive thin film 5a Conductive mask 5b Opening 6 Photoresist 7 Photoresist film 9 Electrodeposition metal layer

Claims (1)

Forming a conductive thin film (4) on a surface of a mother die (3) made of a non-conductive material having translucency;
Patterning the conductive thin film (4) into a desired pattern comprising a conductive mask (5a) and an opening (5b);
A step of closely polymerizing a negative photoresist (6) on the surface not covered with the conductive mask (5a) of the matrix (3) and the surface of the conductive mask (5a);
A photoresist film (7) is formed on the surface corresponding to the opening (5b) that is not covered with the conductive mask (5a) of the mother die (3) by exposing from the back side of the mother die (3) and developing. And a process of
Forming an electrodeposited metal layer (9) on the surface of the conductive mask (5a) by electroforming;
Removing the photoresist film (7) with the electrodeposited metal layer (9) attached to the matrix (3);
Applying metal plating (11) while pressing the metal mesh (10) on the electrodeposited metal layer (9);
A method for producing an electroformed product comprising a step of peeling an electrodeposited metal layer (9) integrated with a mesh (10) by plating (11 ) from a matrix (3).

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