JPS5873186A - Mandrel and electroforming using same or method of producing printed circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mandrel used for electroforming, etc., and an electroforming method using the same, or a method for manufacturing a printed wiring board. Note that the term aluminum used herein means aluminum and aluminum alloys.

Conventionally, when manufacturing products with a certain pattern such as metal vapor deposition masks for semiconductor manufacturing, fine mesh for electron tubes such as vidicon, outer blades of electric shavers, and screens,
Mandrels printed with resin ink or photoresist have been used for molds and notebooks made of stainless steel and other materials. Alternatively, a resist is formed on a stainless steel plate, etc., the areas without resist are plated, and the plating layer is then pressure-bonded to the base material via an adhesive, or to an uncured base material that has adhesive strength. Even in the printed wiring board manufacturing method (hereinafter referred to as transfer method) in which a circuit pattern is formed on a substrate by transferring a plating layer to the substrate, the resist on the mandrel is printed with resin ink or photosensitive. It was applied using the resist method. There are many types of resist printing inks on the market, including epoxy resin,
Mainly resins such as modified epoxy resins such as polyamide-modified epoxy resins, modified phenol resins such as nitrile-modified phenolic resins, and epoxy-modified alkyd resins, mixed with pigments such as graphite and titanium oxide, and solvents such as thinners. used. In addition, photoresists include water-soluble photoresists prepared by mixing a water-soluble polymer compound such as casein, gray, gum arabic, or polyvinyl alcohol with nail chromate, water-soluble bisazide, or diazo compound; rubber-based photoresists that are a mixture of polyvinyl alcohol and cinnamic acid chloride, or polycinnamic acid-based photoresists that are polymerized compounds of the reaction products of vinyl monomers and cinnamic acid groups, quinonediazide and novolac resins. Quinonediazide photoresists, etc., are used.

Electroforming resists must be able to withstand repeated plating and peeling of the plating layer. The transfer method further requires pressure bonding in order to achieve sufficient adhesion between the plating layer and an adhesive or an uncured substrate having adhesive strength. In precision electroforming and transfer, in order to obtain a precise resist image, the surface of the original plate must be made smooth, and it is impossible to roughen the surface to obtain close contact between the resist and the mandrel. Therefore, it is necessary that the resist and the mandrel surface be chemically bonded. Furthermore, if the resist is thick, it tends to be difficult to remove the plating. In transfer, there is a problem in that when a mandrel and an adhesive or an uncured base material having adhesive strength are pressed together, the mandrel sticks to the adhesive or the uncured base material. Due to these problems, there has been no existing resist for electroforming or transfer, especially one that can withstand repeated use of 5 to 10 times or more as a transfer resist.

The present invention was made based on the fact that extremely excellent properties as a resist for electroforming or transfer can be obtained by subjecting an anodic oxide film of aluminum to a simple treatment. As a result, it has excellent adhesion even to thin and smooth surfaces, and when pressure-bonded using the transfer method, it does not stick to adhesives or uncured substrates and has sufficient mechanical strength. Therefore, a resist with excellent heat resistance can be easily obtained.

Aluminum anodic oxide films can be used as is, but they tend to have minute pores and cracks and may be exposed to plating solutions, so it is necessary to devise ways to use them as resists over long periods of time. When a thin film of resin or the like is provided on the anodic oxide film, the resin or the like penetrates into minute pores and cracks and adheres closely, resulting in excellent adhesion and can be used satisfactorily as a resist for a long period of time. The simplest method for treating the anodic oxide film of the present invention is to apply a silicone resin, epoxy resin, polyamide resin, etc. and then wipe it gently with a cloth or the like. At this time,
Resin also adheres to the exposed aluminum pattern, but it can be easily removed by wiping it with a cloth or the like to the extent that it does not affect the plating in any way. On the other hand, the resin on the anodic oxide film gets into the four parts, minute pores or cracks on the anodic oxide film and becomes impossible to wipe away.

Since defects in the resin on the anodic oxide film are compensated for by the anodic oxide film, even if there are some areas where there is no resin, it does not have a large effect. Substances that do not adhere to metals or alloys often adhere to anodized films, so if you apply an adhesive or a room-temperature-curing silicone rubber that does not adhere to uncured substrates, it will be easier to transfer. It can be fully used as a photoresist. Since the anodic oxide film has excellent abrasion resistance and hardly peels off, the resist of the present invention can be repaired by simply recoating with the above-mentioned resin or the like. The details of the treatment method of the anodic oxide film of the present invention will be described later, but the present invention provides a resist for electroforming or transfer having the excellent characteristics as described above by applying a simple treatment to the anodic oxide film of aluminum. This was done because it was suitable for

The material of the mandrel of the present invention is not particularly limited, as long as it is aluminum or an aluminum alloy that has excellent corrosion resistance against plating solutions and provides a good anodic oxide film. For example, industrial pure aluminum, JIS5056 aluminum alloy, etc. are suitable. Further, as for the shape of the mandrel, in addition to foil or plate material, a molded product by casting, forging, machining, pressing, etc. can be used.

In order to form the pattern of the anodic oxide film of the present invention, the anodic oxide film is applied to the entire aluminum surface, an image is formed using a normal etching resist, and then unnecessary parts of the anodic oxide film are dissolved. Another method is to form a regular resist on the aluminum surface and then apply an anodic oxide film to the areas where there is no resist. Both,
It is optional whether or not to leave the anodic acid 1 arsenic film on the side and back surfaces of the original plate, but as long as there is no particular problem, a resist can be formed on the side and back surfaces as well by the method of the present invention.

In the method of forming a pattern by partially dissolving the anodic oxide film, hydrofluoric acid or sodium hydroxide is used to dissolve the anodic oxide film, so an etching resist that can withstand these must be used. Printing with a solvent-removable epoxy resin ink such as 16935 PC manufactured by Nanodahl in the United States or 340C manufactured by Protocoat in West Germany is suitable. Further, as the photoresist, TPR manufactured by Tokyo Applied Chemical Co., Ltd., etc. is suitable. Hydrofluoric acid and sodium hydroxide aqueous solution dissolve not only the anodic oxide film but also the aluminum itself, so deep etching will cause side etch If it remains, it will peel off during plating, or the plating will get into the undercut, making it impossible to peel it off. If the anodic oxide film is thick, uneven dissolution tends to occur, and to avoid this, etching tends to be deep.What about the anodic oxide film? /i or less, preferably 5μ or less.

In the conventional method of forming a resist pattern and then partially anodizing it, the resist needs to withstand the anodizing process, and the printing ink is solder resist 240, 241, 242 photoresist by Knuts Dahl Co., Ltd. PPPPR from Fuji Pharmaceutical Co., Ltd., KPR from Kodanok, USA; DCR-341 from Dinerchem, USA
A value such as 0 is preferable. In this method, part of the aluminum dissolves under the anodizing conditions, and the surface without the anodized film protrudes from the surface of the anodized film, making it possible to avoid side etching, but as the anodizing time becomes longer, Since the resin resist will peel off and the anodic oxide film under the resist will become burnt, it is usually better to set it to IOμ or less, preferably 7μ or less.

In either method, the surface can be cleaned by polishing, degreasing, etching, etc., as appropriate using conventional methods. Normally, preliminary treatments include smoothing by puff polishing or electrolytic polishing, solvent degreasing with acetone, etc., or sodium phosphate degreasing.
When electrolytically degreased using an aqueous sodium carbonate solution, a normal resist exhibits adhesion to the extent that it can withstand the formation or dissolution of an anodic oxide film. Furthermore, in order to improve the adhesion of ordinary resists and obtain a uniform anodic oxide film, it is also good to perform light etching with an aqueous sodium hydroxide solution or the like. These treatments include methods of partially dissolving the anodic oxide film, such as using electrolytic polishing as a smoothing treatment after dissolving the anodic oxide film, or using a normal resist to partially generate the anodic oxide film. The method can be used in a wide variety of ways, including performing deep etching before forming the anodic oxide film in order to create a large step between the surface without the anodized film and the surface of the anodized film. These methods can also be used for cleaning before plating after forming a pattern with an anodic oxide film and applying a resin, but this process will be described later.

In the method of obtaining a pattern by partially dissolving the anodic oxide film, the etching resist of the anodic oxide film may be left as is when applying the resin of the present invention, but in the transfer method, the etching resist of the anodic oxide film may be left as is. The resist used for partial dissolution is thick and has problems such as the plating being difficult to peel off, so it is often better to remove it by dissolving it. Since the alkali-removable type resist also destroys the aluminum and anodic oxide film when dissolved with an alkali, it is preferable to use a type of resist that can be removed with a solvent such as Kijirol and perform the solvent removal.

The anodizing treatment may be performed by direct current electrolysis, alternating current electrolysis, alternating current electrolysis, etc. in a sulfuric acid bath, an oxalic acid bath, a chromic acid bath, or the like. In particular, in order to enlarge the fine pores, we performed direct current electrolysis using a phosphoric acid bath.After the normal anodizing treatment, we performed light etching with a sodium hydroxide aqueous solution, and after the anodizing treatment, we applied a temperature of 200°C to 500°C. Heating it to increase the crankshaft is effective in improving the adhesion of the resin etc. coated thereon.

The anodic oxide film as it is is not sufficient to withstand long-term use as an electroforming or transfer resist.
As already mentioned, it is necessary to apply resin. Many methods can be applied to this treatment, but they can be divided into coating methods and electrolytic methods. As the coating method, the method of coating silicone resin fJM etc. as described above can be applied. The application method may be dipping, spraying, brushing, or using a spatula. It is necessary to remove the resin and the like from the area to be plated, but the above-mentioned wiping method is the simplest method for this. In the method of forming a resist and subjecting it to partial anodic oxidation, it is also possible to apply a resin or the like before removing the resist and remove the resin or the like on the resist by dissolving the resist. As another application method, by applying an emulsion of fluororesin or heptad graphite and baking it, it is also possible to obtain a resist that does not adhere to an adhesive or an uncured base material having adhesive strength using a transfer method. As the electrolytic method, for example, electrophoretic coating of acrylic resin or Epoquin-modified acrylic resin, or coating of molybdenum disulfide by electrolysis in ammonium thiomolybdate is also possible. In the electrolytic method, a resist is first formed and then partially anodized, and this resist is used as a resist during electrolysis.

A wide variety of resins can be used for painting, but
In particular, in the transfer method, releasability from the adhesive or uncured base material,
Silicone resin is the most useful in terms of ease of application and protection against anodic oxide films. As the silicone resin, commercially available room temperature curing silicone rubber (KE- from Shin-Etsu Chemical Co., Ltd.) is used.
42RTV, KE-441RTV, KE-471RT
V) Although it is easy to handle, from the point of view of scratch resistance etc., a silicone rubber made by dissolving the initial resinous compound of silicone in Doruol, Celsolve, etc. is applied and heated at 150°C-16.
A hard coating film baked at 0°C is better. Salts such as iron, cobalt, zinc, etc. may be used as desiccant agents. Addition of pigments such as graphite is optional, but addition of aluminum powder shortens the life of the resist. Using fluorosilicone rubber instead of pure silicone resin improves solvent resistance, but modified silicone resins such as alkyd-modified silicone resins and phenol-modified silicone resins may stick to some adhesives or uncured substrates. . In the case of room-temperature curing silicone rubber, for example, a resist is formed using ordinary solvent-removable epoxy resin ink, a partially anodized film is formed, the silicone resin is applied as is, and the silicone rubber is coated with paper or cloth. A method of preventing adhesion to the surface to be plated can be applied by squeezing the ink resist and then dissolving the ink resist in a solvent and peeling off the silicone rubber layer above it. Dissolution of the resist in a solvent is promoted by applying ultrasonic waves, but the silicone rubber in the anodic acid (arsenic film) can be maintained.

A method in which the applied resin is dissolved at the same time as the ink resist or photoresist is dissolved does not require pretreatment for plating. However, in cases where high-temperature baking is required, such as with 7-base resin, or where the solvent that dissolves the ink resist or photoresist disturbs the applied resin, the resin may be applied after removing the resist. Since the resin will be attached to the surface to be plated, the resin will remain on the surface to be plated. If the area is to be wiped off, pretreatment is not necessary in this case either, but if the area is lightly etched with sodium hydroxide or the like, the aluminum will dissolve and the remaining resin will also come off.

When plating directly onto aluminum and peeling or transferring this plating layer to produce a product, it is important to select a plating solution that is less corrosive to aluminum. For example, if you are using copper plating, use copper pyrophosphate plating solution.
For nickel plating, a bath with low chloride content, such as the one shown below, is preferable. Also, avoid leaving it in the plating solution for a long time, and immerse it in the plating solution with a voltage applied.

In order to prevent corrosion of aluminum, it is also a good method to apply anti-corrosion plating to the parts to be plated in advance. If chromium plating is performed, the plating on top of it can be easily peeled off, and the plating on top of copper plating or nickel plating can also be peeled off by treatment with chromic acid.

In the case of electroforming, the end of the plating layer is peeled off with the tip of a knife, and by pulling up that part, the plating layer can be peeled off from the base plate.

In the case of transfer, the plating layer can be attached to the base material by pressing it to the base material through a film adhesive, or by pressing it to the base material coated with adhesive and then peeling off the base material and the base plate. It is possible to transfer.

As described above, the matrix of the present invention forms a resist with good adhesion on a smooth material, and is particularly suitable for use in forming printed wiring boards by the transfer method.

Hereinafter, specific examples of the present invention will be described.

(Example 1) Q: A 2 mm aluminum foil was anodized. Anodizing treatment conditions: 30% sulfuric acid, bath temperature 15°C.
The AC voltage was set to 15 V and the test was carried out for 1 minute. On top of this, a thermosetting silicone adhesive SE-[701 (manufactured by Toray Silicone Co., Ltd.) was screen printed to form a resist.

After curing the resist at 120° C. for 7 minutes, it was immersed in a solution of 10% 7-nitrogen acid for 2 minutes to dissolve the anodic oxide film in the areas where the resist was not formed. On top of that, 35 horns of copper plating was applied using a birophosphate copper plating solution, and an epoxy adhesive was applied in advance and transferred to a semi-cured polyimide film. Transfer conditions: 1'80°C140kf/
cm2.15 minutes, a good flexible printed wiring board was obtained. Plating and transfer were repeated five times under the same conditions, but no abnormality was observed in the resist.

(Example 2) A hemispherical mandrel was obtained by deep drawing a 0.3 mm JIS5056 aluminum foil, and nickel electroforming was performed on this to produce a hemispherical nickel mesh.

Before deep drawing, resist ink Nn16935 (manufactured by Nanodahl, USA) was screen printed on the portions corresponding to the holes of the mesh, and after deep drawing, anodization treatment was performed. Processing conditions are 20% sulfuric acid, bath temperature 10'C, voltage 20V.
So I went for 10 minutes. Furthermore, after being immersed in a 36% aqueous solution of 2.' HNO for 5 minutes, the sample was used as an anode in an F/-R solution containing a 1% by weight molybdenum disulfide solution, and electrodeposition was performed at 250 V for 10 minutes. and deposited molybdenum disulfide on the anodized film. The resist is removed by applying ultrasonic vibration in Akaton,
Using this as a mandrel, 25μ nickel electroforming was performed in a Watt bath. A good mesh was obtained by dissolving and removing the aluminum alloy foil in a 6% sodium hydroxide solution.

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Claims (3)

[Claims] (1) A mandrel characterized by having a pattern formed by an anodic oxide film on aluminum or an aluminum alloy. (2) A pattern of K anodized film is formed on aluminum or an aluminum alloy, and a layer of 7-noresin, silicone resin, graphite fluoride, or graphite disulfide alone or in a mixture is further provided on the pattern. mandrel. (3) Using a mandrel in which a pattern is formed by an anodized film on aluminum or an aluminum alloy, and a layer of fluororesin, silicone resin, fluorinated graphite, or graphite disulfide alone or in a mixture is provided on the pattern, the mandrel is An electroforming method characterized by applying plating to a portion where a pattern is not formed and peeling off the plated portion. (=1.) Using a mandrel in which a pattern is formed by an anodized film on aluminum or an aluminum alloy, and a layer of fluororesin, silicone resin, fluorinated graphite, or graphite disulfide alone or in a mixture is provided on the nofcoon ball. , Plating is applied to the part of the mandrel where the pattern is not formed, and then the plating layer is bonded to the base material via an adhesive or to an uncured base material having adhesive strength. A method of manufacturing a circuit pattern by transferring it to a substrate.