JPH0732544A - Coppered laminate with paper base and its manufacture - Google Patents

Abstract

PURPOSE:To provide a coppered laminate with a paper base, of which the dimensional stability is favorable and the warpage of which is small by laminating a macrocrystalline electrolytic copper foil, of which the high temperature elongation percentage is specified, on one surface or both surfaces of a paper base which is impregnated with a thermosetting resin, by an adhesive layer. CONSTITUTION:A macrocrystalline electrolytic copper foil of which the elongation percentage at 180 deg.C is 8.5% or higher, is laminated on one surface or both surfaces of a paper base which is impregnated with a thermosetting resin, by an adhesive layer. An adhesive which forms the adhesive layer is not particularly limited as long as the major component of which is a thermosetting resin, etc. Generally, an epoxy resin, phenol resin or melamine resin, etc., are applied. In order to generate a macrocrystalization on the electrolytic copper foil, it is required to provide a heat treatment process in either one of the manufacturing pocesses of the coppered laminate. For the heat treatment conditions, e.g. 10-20 minutes at 170-180 deg.C can be cited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper substrate copper clad laminate for printed wiring boards used in electric equipment, electronic equipment and the like and a method for producing the same, and particularly to a paper substrate having good dimensional stability and small warpage. The present invention relates to a copper clad laminate and a method for manufacturing the same.

[0002]

2. Description of the Related Art Paper-based copper-clad laminates, which are widely used in printed wiring boards for consumer electric and electronic devices such as televisions and VTRs, include prepregs and adhesives in which a paper substrate is impregnated with phenolic resin. It is manufactured by laminating a copper foil with an adhesive coated with and heat-pressing.

In recent years, in the process of processing a printed wiring board, the processing equipment is being automated, and the processing speed is being increased and the processing area is being rationalized, such as enlarging the printing area. In addition, in order to cope with the increase in mounting density due to miniaturization of electronic equipment,
The surface mount method has been adopted. In order to meet these demands, a laminated plate having good dimensional stability and small warpage has been required.

[0004] In response to the demand for reducing the warpage of the paper base copper clad laminate, improvements have been made on the side of the paper base that has been used conventionally. For example, the aspect ratio of the tensile strength of the paper base material is improved (Japanese Patent Publication No. 4-4144, Japanese Patent Publication No. 4145, Japanese Patent Publication No. 3-243341), and the elongation of kraft paper is improved (Japanese Patent Publication No. 3-243). Japanese Patent No. 55239, Japanese Patent Laid-Open No. 3-1993
No. 60189 and Japanese Patent Laid-Open No. 3-62993) have been proposed.

However, it is known that the area ratio of the copper foil remaining as the wiring pattern after etching has a great influence on the dimensional change and warpage of the printed wiring board. Therefore, it was not possible to sufficiently improve the characteristics of dimensional change and warpage only by improving the paper base material.

Therefore, the present inventor has focused on copper foil, which is another element constituting the paper-based copper-clad laminate.

As the copper foil used in the copper clad laminate for printed wiring boards, electrolytic copper foil is often used. Electrolytic copper foil is
Rotate the cathode and the anode in an acidic copper electrolyte, place copper continuously on the rotor by electrolysis, and then wind the copper while continuously stripping the deposited copper from the rotor. Is manufactured by.

[0008] The electrolytic copper foil is classified into a normal foil and a foil having good hot elongation in the classification according to IPC MF-150F. A foil with good hot elongation has an elongation of 2 at 180 ° C.
% Or more (35 μm thick) foil. Currently, for example, 3EC-III foil (manufactured by Mitsui Kinzoku Co., Ltd.) is used as a copper foil having good hot elongation. However, even if such a copper foil having good hot elongation is used for a paper-based copper-clad laminate, dimensional changes and warpage cannot be sufficiently improved.

[0009]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a paper-based copper clad laminate having a small warpage of the laminate and good dimensional stability without being affected by the area ratio of the copper foil. It is to provide the manufacturing method.

[0010]

The present inventor has found that not only the hot elongation of the electrolytic copper foil but also the crystallization of the electrolytic copper foil influences the dimensional stability and warpage of the laminate. Invented.

That is, the paper base copper clad laminate of the present invention is
On one or both sides of the paper substrate impregnated with thermosetting resin,
It is characterized in that an electrolytic copper foil, which has an elongation at 180 ° C. of 8.5% or more and is made into a large crystal, is laminated via an adhesive layer.

The electrolytic copper foil used in the paper-based copper-clad laminate of the present invention has an elongation at 180 ° C. of 8.5% or more, and causes macrocrystallization when heated. By using such an electrolytic copper foil, dimensional stability is good,
Moreover, a paper-based copper-clad laminate having a small warpage can be obtained. When the electrolytic copper foil used has an elongation at 180 ° C. of less than 8.5%, or when the copper foil of the copper-clad laminate does not undergo macrocrystallization, strain occurs during cooling to room temperature after heating. As a result, dimensional changes and warpage increase, which is not preferable.

The term "big crystallization of the electrolytic copper foil" as used herein means a phenomenon in which the crystal grains of the electrolytic copper foil grown in a columnar shape from the cathode to the anode are heated, and the adjacent crystal grains are fused and lump-sized. Say.

In general, in the electrolytic copper foil obtained by the usual method, the influence of impurities existing in the crystal grain boundaries is not clear, but it is difficult for large crystals to occur due to heating. 3EC-II described above
I copper foil also has good elongation at 180 ° C, but it does not cause megacrystallization. However, the electro-deposited copper foil produced by the method described in JP-A No. 62-10291 has a good hot elongation at 180 ° C., and causes crystallization at relatively low temperatures. The electrolytic copper foil described in Japanese Patent Laid-Open No. 62-10291 is manufactured by a method using an electrolytic solution treated with activated carbon. At least one surface of the electrolytic copper foil is preferably subjected to a surface roughening treatment in order to increase the adhesive strength. Further, it is desirable that rust-preventive treatment is performed to prevent oxidative discoloration due to heat during hot molding. The thickness of electrolytic copper foil is 1
Those having a thickness of 2 to 70 μm are used, and those having a thickness of 18 to 35 μm are more preferably used.

The adhesive forming the adhesive layer is not particularly limited as long as it contains a thermosetting resin or the like as a main component. Generally, thermosetting resins such as epoxy resin, phenol resin, melamine resin, and isocyanate resin, thermoplastic resins such as polyvinyl acetal resin, acrylic resin, polyamide resin, synthetic rubber, and curing agents, curing accelerators, flame retardants. Etc., and an adhesive varnish dissolved in an organic solvent is applied to one surface of the electrolytic copper foil and dried. The compounding amount of the resin is not particularly limited.

Such a paper-based copper-clad laminate of the present invention is
On one or both sides of the paper substrate impregnated with thermosetting resin,
When a copper foil having an adhesive layer provided on one surface of an electrolytic copper foil having an elongation rate of not less than 8.5% at 180 ° C. and being heated to cause giant crystal formation and heat-pressed, the giant crystal of the copper foil is formed. It can be manufactured by providing a heat treatment step at a heat treatment temperature of 170 ° C. or higher at which heat treatment occurs.

The copper foil used in the copper clad laminate of the present invention is
When it is heated to a high temperature of 170 ° C. or higher, it causes crystallization, and the crystal change causes the elongation at a high temperature to be maintained. In order to cause such electro-deposited copper foil to become a large crystal, it is necessary to provide a heat treatment step in any of the steps of manufacturing the copper clad laminate. The heat treatment condition is, for example, 170
It may be 10 to 20 minutes at ˜180 ° C. These can be heated by a usual method such as hot air drying in the open.

This heat treatment step is optionally provided in the step of producing the paper-based copper clad laminate. For example, with respect to the copper foil before applying the adhesive, in the drying step after applying the adhesive, in the step of laminating heat and pressure molding,
Although it is carried out in a post-heating step after molding, it is preferably carried out in a post-heating step after molding.

[0019]

In the present invention, since the copper foil having a high elongation at high temperature is used and the copper foil has a large crystal, the shrinkage of the base material and the copper foil which occurs during cooling after heating to room temperature The distortion due to is eliminated. Therefore, even after the copper foil is etched to form the wiring pattern, the shrinkage of the laminated plate is small, and the dimensional change and the warp are improved.

[0020]

EXAMPLES The present invention will be specifically described below based on Examples and the like.

Example 1 A polyvinyl butyral (trade name) was prepared on the roughened surface of an electrolytic copper foil having a thickness of 35 μm and an elongation rate of 12% at 180 ° C. manufactured by the method described in JP-A-62-1291. : Denka Butyral # 5000A, manufactured by Denki Kagaku Kogyo Co., Ltd., 50 parts by weight, phenol resin (trade name: Siynol BLS3)
64, Showa High Polymer Co., Ltd.) 30 parts by weight and an epoxy resin (trade name: YD128, Toto Kasei Co., Ltd.) 20 parts by weight dissolved in a methyl ethyl ketone-methanol mixed solvent to give a dry thickness of 30 to 40 μm. It was applied as described above, air-dried at room temperature, and then dried in an open at 130 ° C. for 5 minutes to prepare a copper foil with an adhesive. Then, kraft paper was impregnated with a phenol resin varnish so that the amount of the resin after drying was 50% by weight, and eight prepregs prepared by drying and the copper foil with the adhesive were laminated, and 150 ° C., 100 kg
It was heated and pressed at f / cm ² for 1 hour to obtain a paper-based copper-clad laminate having a thickness of 1.6 mm.

Next, the paper-based copper-clad laminate was heated in an oven at 170 ° C. for 20 minutes to prepare a paper-based copper-clad laminate in which the copper foil was crystallized.

Example 2 A polyvinyl butyral (trade name: trade name) was prepared on the roughened surface of an electrolytic copper foil having a thickness of 35 μm and an elongation at 20 ° C. of 20% produced by the method described in JP-A-62-1291. Denka Butyral # 5000, manufactured by Denki Kagaku Kogyo Co., Ltd., 45 parts by weight, epoxy resin (trade name: Epotote YDCN70)
1, Toto Kasei Co., Ltd.) 20 parts by weight, melamine resin (trade name: Uban 22R, Mitsui Toatsu Chemical Co., Ltd.) 35 parts by weight, polyisocyanate resin (trade name: Millionate M)
S-50, manufactured by Nippon Polyurethane Industry Co., Ltd.) 8 parts by weight, and 0.1 parts by weight of benzoic acid were dissolved in a methyl ethyl ketone-methanol mixed solvent to prepare an adhesive varnish having a dry thickness of 30-4.
It was applied so as to have a thickness of 0 μm, air-dried at room temperature and then dried at 140 ° C. for 5 minutes to prepare a copper foil with an adhesive.

Next, a paper-based copper-clad laminate was prepared in the same manner as in Example 1. This paper-based copper-clad laminate was heated in an oven at 170 ° C. for 20 minutes to prepare a paper-based copper-clad laminate in which the copper foil had grown into crystals.

Example 3 Used in Example 1 on a roughened surface of a 35 μm thick electrolytic copper foil having an elongation of 18% at 180 ° C. manufactured by the method described in JP-A-62-1291. An adhesive varnish similar to the above was applied and dried in the same manner as in Example 1 to produce an adhesive-attached copper foil. Next, a paper-based copper-clad laminate was prepared in the same manner as in Example 1.

Example 4 Used in Example 1 on a roughened surface of a 35 μm-thick electrolytic copper foil having an elongation of 15% at 180 ° C. manufactured by the method described in JP-A-62-10291. An adhesive varnish similar to the above was applied and dried in the same manner as in Example 1 to produce an adhesive-attached copper foil.

Next, kraft paper was impregnated with a varnish consisting of an epoxy resin and a curing agent so that the amount of the resin after drying was 45% by weight, and eight prepregs prepared by drying and the copper foil with the adhesive were laminated. 170 ℃, 120kgf
/ Cm ² was heated and pressed for 1 hour to obtain a paper-based copper-clad laminate having a thickness of 1.6 mm.

Comparative Example 1 Used in Example 1 on a roughened surface of a copper foil having a thickness of 35 μm and an elongation of 12% at 180 ° C. manufactured by the method described in JP-A-62-10291. An adhesive varnish similar to the above was applied and dried in the same manner as in Example 1 to produce an adhesive-attached copper foil. Next, a paper-based copper-clad laminate was prepared in the same manner as in Example 1. Since the post-heating was not performed, the copper foil did not become a large crystal.

Comparative Example 2 A 35 μm thick copper foil (B having an elongation of 2% at 180 ° C.)
The same adhesive varnish as that used in Example 1 was applied to the roughened surface of the EC foil, manufactured by Mitsui Kinzoku Co., Ltd., in the same manner as in Example 1, and dried to produce a copper foil with an adhesive. Next, a paper-based copper-clad laminate was prepared in the same manner as in Example 1. This paper-based copper-clad laminate was heated in an oven at 170 ° C. for 20 minutes.

Comparative Example 3 Example 1 was applied to the roughened surface of a 35 μm thick copper foil (BEC-III foil, manufactured by Mitsui Kinzoku Co., Ltd.) having an elongation of 10% at 180 ° C.
The adhesive varnish similar to that used in Example 1 was applied and dried in the same manner as in Example 1 to prepare an adhesive-attached copper foil. next,
A paper-based copper-clad laminate was prepared by the same method as in Example 1 (° C). This paper-based copper-clad laminate was placed in an oven at 170 ° C for 2
Heat for 0 minutes.

Experimental Example The maximum warpage of the paper-based copper clad laminates (500 mm × 500 mm) obtained in Examples 1 to 4 and Comparative Examples 1 to 3 was measured according to JIS C6481. In addition, a sample for observing a cross-sectional crystal was prepared from the laminated plate, and the presence or absence of megacrystallization was evaluated. The results of these measurements are shown in Table 1.

[0032]

[Table 1]

A paper-based copper-clad laminate (300 mm × 3
The dimensional change rate after etching (00 mm) and after heat treatment was measured according to JIS C6481. The results are shown in Table 2.

[0034]

[Table 2]

As is clear from Tables 1 and 2 above, 18
The paper-based copper-clad laminates of Examples 1 to 4 using the electrolytic copper foil having a high 0 ° C. hot elongation and large crystal size were compared with the paper-based copper-clad laminates of Comparative Examples 1 to 3. The warpage is small and the dimensional stability is good.

[0036]

As described above, the paper-based copper-clad laminate of the present invention has small warpage and good dimensional stability.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // B29C 43/18 7365-4F B29K 105: 08 705: 10

Claims (3)

[Claims] 1. An electrolytic copper foil having an elongation rate at 180 ° C. of 8.5% or more and being crystallized is provided on one or both sides of a paper base material impregnated with a thermosetting resin via an adhesive layer. A paper-based copper-clad laminate characterized by being laminated. 2. An adhesive agent on one or both sides of a paper base material impregnated with a thermosetting resin, an elongation rate at 180 ° C. of 8.5% or more, and one side of an electrolytic copper foil which is crystallized by heating. A method for producing a paper-based copper-clad laminate, which comprises providing a heat treatment step in which, when the copper foils provided with layers are laminated and heat-pressed, the copper foils are crystallized. 3. An adhesive on one side or both sides of a paper base material impregnated with a thermosetting resin, an elongation rate at 180 ° C. of 8.5% or more, and one side of an electrolytic copper foil which is crystallized by heating. A method for producing a paper-based copper-clad laminate, which comprises laminating copper foils provided with layers and heat-pressing at a heating temperature of 170 ° C or higher.