JP3779555B2 - Method for producing printed circuit board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of making a printed circuit board using the contact adhesive copper foil laminate.
[0002]
[Prior art]
Along with the downsizing and high performance of electronic devices, printed circuit boards mounted in them are becoming more dense due to higher layers, thinner thickness, smaller through-hole diameters, and reduced hole spacing. . In addition, printed circuit boards mounted on information terminal devices such as mobile phones and mobile computers are large-capacity information centered on plastic packages that mount MPUs directly on printed circuit boards and printed circuit boards for various modules. Is required to be processed at high speed, and signal processing speedup, low transmission loss, and further downsizing are required. For this reason, printed circuit boards are becoming more dense, and finer wiring is required.
[0003]
The printed circuit board is produced by, for example, producing a copper-clad laminate using an adhesive-attached copper foil and forming a fine wiring circuit by etching. In order to form this fine wiring circuit by etching, it is necessary to make the thickness of the copper foil as thin as possible in consideration of the aspect ratio of the circuit. On the other hand, when the copper foil is too thin, for example, when the thickness is 10 μm or less, the conventional method of forming the adhesive layer by direct coating or laminating when producing the adhesive-attached copper foil causes wrinkles or scratches on the copper foil. Etc. occur. On the other hand, a method of supporting a copper foil having a thickness of about 3 μm on a thick copper foil or other metal foil has also been proposed, but handling becomes difficult due to heavy weight and metal powder mixing when cutting into a sheet. It is not widely used because of its difficulty.
[0004]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems in the prior art. An object of the present invention is to provide a way you prepare Ku printed circuit board such that the wrinkles and scratches occur on the copper foil layer with an adhesive copper foil laminate.
[0005]
[Means for Solving the Problems]
As a result of the study, the present inventors have found that the above problem can be solved by using a resin film that is water-soluble or swelled with water as a support for copper foil, and has completed the present invention.
[0006]
That is, the method for producing a printed circuit board according to the present invention includes an adhesive-coated copper foil laminate in which an adhesive layer is provided on one side of a copper foil and a protective layer made of a water-soluble or water-swelling resin film is provided on the other side. Is attached to a printed circuit board and immersed in water to remove the protective layer . Protective layer made of a resin film to swell in water-soluble or water, polyvinyl alcohol, polyvinyl pyrrolidone, have the preferred Formed polyvinyl ether.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The copper foil laminate with an adhesive used in the method for producing a printed circuit board of the present invention will be described. Before the copper foil is provided with the adhesive layer, the copper foil layer is first formed on one surface of a resin film that is swollen with water or water. It is provided as. As a method of forming a copper foil layer on a water-soluble or water-swelling resin film, a method of bonding a thermoplastic water-soluble or water-swelling resin film to a copper foil, water-soluble or water-swelling A method of directly forming a copper foil on a resin film by a method such as sputtering, vapor deposition, or electroless plating, or a method such as sputtering, vapor deposition, or electroless plating directly on a resin film that swells with water or water. After forming the copper foil, a method of growing to a desired thickness by electrolytic plating can be used. Further, the thickness of the copper foil or copper foil layer is preferably 10 μm or less in consideration of etching of fine wiring.
[0008]
As the water-soluble or water-swelling resin film that serves as a copper foil protective layer, films such as polyvinyl alcohol, polyvinyl ether, and polyvinyl pyrrolidone are used. The thickness of the resin film is not particularly limited as long as it has enough waist to support the copper foil. The surface of the resin film may be subjected to a treatment for imparting weak adhesiveness, a release treatment, or the like.
[0009]
Next, an adhesive layer is formed on the copper foil layer provided on the resin film as described above. The resin constituting the adhesive layer is not particularly limited, and any known resin that has been conventionally used for adhesive-coated copper foils for producing printed circuit boards can be used. Specifically, for example, an epoxy resin, a mixture of an epoxy resin and a phenol resin, a mixture of an epoxy resin and an amine compound, a rubber-modified epoxy resin, an elastomer component added to the resin mixture, a maleimide resin, a maleimide and an amine Mixtures, mixtures of maleimide and methallyl compounds, bismaleimide-triazine resins, polyimide resins, polyphenylene ether resins, and mixtures of each of the above can be used.
[0010]
An adhesive layer can be formed by apply | coating the adhesive composition which consists of said resin etc. on a copper foil layer by a conventional method. After application, the formed adhesive layer is preferably heated to a semi-cured form. Although the film thickness of an adhesive bond layer is not specifically limited, Generally, it sets to the range of 8-100 micrometers.
[0011]
Since the protective layer of the adhesive-attached copper foil laminate used in the present invention is easily dissolved or swelled in water, when a printed circuit board is produced, after bonding the adhesive-attached copper foil laminate to the printed circuit board, for example, What is necessary is just to remove by immersing in water.
[0012]
【Example】
Below, this invention is demonstrated based on an Example.
Example 1 (Preparation example of copper foil laminate with adhesive)
A copper foil layer having a thickness of 3 μm was formed on one side of a polyvinyl alcohol film (CP-7000, manufactured by Kuraray Co., Ltd.) having a thickness of 50 μm by vapor deposition. Next, 40 parts by weight of an epoxy resin (trade name: Epomic R-301, manufactured by Mitsui Petrochemical Co., Ltd.), 20 parts by weight of a rubber-modified epoxy resin (trade name: EPOTOHTO YR-102, manufactured by Toto Kasei Co., Ltd.), a polyvinyl acetal resin (commodity) Name: Denkabutyral # 5000A, manufactured by Denki Kagaku Kogyo Co., Ltd. 30 parts by weight, melamine resin (trade name: Yuban 20SB, manufactured by Mitsui Toatsu Chemicals Co., Ltd.) 10 parts by weight (as solids), latent epoxy resin curing agent (dicyandiamide) ) 2 parts by weight (added in a dimethylformamide solution with a solid content of 25% by weight), 0.5 part by weight of a curing accelerator (trade name: Curesol 2E4MZ, manufactured by Shikoku Kasei Co., Ltd.) in a toluene-methanol 1: 1 mixed solvent An adhesive composition having a solid content of 25% by weight was prepared by dissolution. This adhesive composition was applied on the copper foil layer formed on the polyvinyl alcohol film, air-dried, and then heated at 130 ° C. for 5 minutes to form an adhesive layer having a thickness of 30 μm. In the obtained copper foil laminate with adhesive, no problem in appearance was recognized.
[0013]
Example 2 (Preparation example of copper foil laminate with adhesive)
A copper foil layer having a thickness of 5 μm was formed by vapor deposition on one surface of a polyvinyl alcohol film (CP-7000, manufactured by Kuraray Co., Ltd.) having a thickness of 50 μm. 2,2-bis [4- (aminophenoxy) phenyl] propane, 3,3′-dicarboxy-4,4′-diaminodiphenylmethane, aminopropyl-terminated dimethylsiloxane octamer, 2,3 ′, 3 100 parts by weight of a siloxane-modified polyimide having a molecular weight of 25,000 consisting of 4'-biphenyltetracarboxylic dianhydride (siloxane modification rate 8%), 69 parts by weight of 4,4'-bismaleimide diphenylmethane, 24 parts by weight of dimethallylbisphenol A Was added to tetrahydrofuran and sufficiently mixed and dissolved to obtain an adhesive composition having a solid content of 30% by weight. This adhesive composition was applied on the copper foil layer formed on the polyvinyl alcohol film and heated at 140 ° C. for 5 minutes to form an adhesive layer having a thickness of 60 μm. In the obtained copper foil laminate with adhesive, no problem in appearance was recognized.
[0014]
Example 3 (Preparation example of copper foil laminate with adhesive)
Polyvinyl alcohol film having a thickness of 50 [mu] m (CP-7000, manufactured by Kuraray Co., Ltd.) copper foil layer was formed by sputtering on one surface of, to form a copper foil layer having a thickness of 3μm by electroless plating. Next, 26.4 parts by weight of a dicyclo type epoxy resin (trade name: HP-7200, manufactured by Dainippon Ink & Co.), 12.3 parts by weight of a resole phenol resin (trade name: Shonor CKM 2400, manufactured by Showa Polymer Co., Ltd.) , 1.3 parts by weight of diaminodisiloxane (trade name: TSL9306, manufactured by Toshiba Silicone) and 56.3 parts by weight of Epofriend A1020 (manufactured by Daicel Chemical) were dissolved in 216.9 parts by weight of tetrahydrofuran. An 8% by weight adhesive composition was prepared. This adhesive composition was applied onto the copper foil layer formed on the polyvinyl alcohol film, air-dried, and then heated at 150 ° C. for 5 minutes to form an adhesive layer having a thickness of 30 μm. . In the obtained copper foil laminate with adhesive, no problem in appearance was recognized.
[0015]
Comparative example (manufacturing example of copper foil laminate with adhesive)
From the film in which the copper foil layer was formed on the polyvinyl alcohol film produced in Example 1, the polyvinyl alcohol film was removed by washing with water to obtain a copper foil having a thickness of 3 μm. The adhesive composition used in Example 1 was applied to this copper foil, air-dried, and then heated at 130 ° C. for 5 minutes to prepare a copper foil with an adhesive having an adhesive layer having a thickness of 30 μm. At that time, the copper foil was wrinkled in the process of drying the adhesive, and the yield of non-defective parts was about 50%.
[0016]
Example 4 (Example of printed circuit board production)
A commercially available 0.2 mm glass epoxy prepreg was layered on the adhesive of the copper foil laminate with adhesives of Examples 1 to 3, and temporarily bonded at 140 ° C., and then the protective layer was immersed in water at 50 ° C. for 60 seconds. Then, the laminate was further pressed at a pressure of 30 kg / cm ² and a temperature of 170 ° C. for 60 minutes to produce a laminate. In the case of the Example of this invention, there was no wrinkle generation | occurrence | production in a copper foil layer, and the favorable laminated sheet was produced.
[0017]
Similarly, when a laminated board was produced using the copper foil with an adhesive of the comparative example, wrinkles at the time of temporary pressure bonding remained, and a good product was not obtained.
[0018]
Furthermore, these laminates were etched was formed a comb-shaped electrodes of 15μm pitch, but the embodiment of the present invention were able to form a comb-shaped electrode without problems, an adhesive copper foil of Comparative Example When used , wrinkles at the time of provisional pressure bonding remained, and a good product was not obtained.
[0019]
【The invention's effect】
The method for manufacturing a printed circuit board of the present invention, we either having the above configuration, the protective layer to swell in water-soluble or water can be easily removed by water, wrinkles and scratches in the copper foil layer of the printed circuit board to be manufactured it is not the name that but occur.

Claims (3)

An adhesive layer provided on one surface of the copper foil, the other surface in a water-soluble or with contact adhesive a protective layer made of a resin film swollen with water foil laminate affixed to a printed circuit board, immersion in water A method for producing a printed circuit board, wherein the protective layer is removed . The method for producing a printed circuit board according to claim 1, wherein the copper foil has a thickness of 10 μm or less. The method for producing a printed circuit board according to claim 1, wherein the protective layer made of a water-soluble or water-swelling resin film is formed of any one of polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl ether.