JPH0613749A - Copper foil for printed circuit use and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a copper foil for printed circuit use, which is superior in migration resistance and maintains high bonding strength between the copper foil and a board when the copper foil is used on a copper-clad laminated board for printed circuit, and a method of manufacturing the copper foil. CONSTITUTION:A copper foil for printed circuit is a foil, which has a ternary alloy coating layer made of nickel, molybdenum and cobalt on the surface of the copper foil, and is manufactured by a method wherein a copper foil is dipped in a plating bath, in which nickel ions, molybdenum acid ions and cobalt ions coexist, and a cathode treatment is performed to form the ternary alloy coating layer made of nickel, molybdenum and cobalt on the surface of the copper foil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper foil for printed circuits and a method for producing the same, and more specifically, when used for producing a copper clad laminate, while maintaining high adhesive strength between the copper foil and the substrate, Particularly, the present invention relates to a copper foil for a printed circuit capable of providing a copper clad laminate having excellent migration resistance and a method for producing the same.

[0002]

2. Description of the Related Art As electronic components mounted on printed wiring boards have become smaller, higher in density and higher in performance, the requirements for the quality of copper foil, which is a conductor circuit material, have become more stringent, resulting in higher reliability. Characteristics have come to be required.

The most basic required characteristic is that the adhesive strength between the copper foil and the resin substrate is excellent. Regarding this, copper foil is heated and pressed against a resin base material, and not only the adhesive strength immediately after lamination, but also under severe environmental conditions such as being immersed in chemicals such as acid and alkali, or being heated. Maintaining a high adhesive strength after being placed is still an extremely important issue for obtaining high reliability in quality.

Therefore, as a general means for solving the above problems, the surface of the copper foil to be laminated on the resin base material is roughened, for example, by cathodic electrolysis using a copper plating solution. A process of electrodepositing copper particles on the bonding surface is performed. As a result, the adhesive strength is remarkably improved by combining the increase in the surface area of the copper foil surface and the anchoring effect brought about by the granular material.

However, the formation of the rough surface alone does not improve the adhesive strength characteristics such as chemical resistance and heat resistance, and the deterioration rate of so-called adhesive strength increases, which does not reach the practical level.

For this reason, after the surface roughening treatment, various surface treatment layers are formed to reduce the deterioration rate of the adhesive strength. Many proposals have been made for the formation of the surface treatment layer on the copper foil surface.
For example, a copper foil having a chromate layer formed on a roughened surface (Japanese Patent Publication No. 61-33908), or a copper foil having a zinc layer formed on the roughened surface and then a chromate layer (special Japanese Patent Publication No. 61-33906) has been proposed. However, although the copper foils according to these prior arts are effective in improving some of the above-mentioned required characteristics, they may deteriorate them.

Specifically, a copper foil having a chromate layer has an insufficient effect of improving the adhesive strength, especially after heating for a long time. Further, in the case of a copper foil having a zinc layer and then a chromate layer formed thereon, although the adhesive strength after heating is improved to some extent, the adhesive strength after dipping in hydrochloric acid, which is regarded as important for chemical resistance, is remarkably lowered, and its deterioration is caused. Since the rate is below the practical level, it does not sufficiently correspond to high quality and high reliability.

On the other hand, a copper foil obtained by forming a cobalt layer containing either or both of molybdenum and tungsten on the surface of the copper foil (Japanese Patent Publication No. 2-24037).
Copper foil (Japanese Patent Publication No. 62-142389) obtained by forming a nickel layer containing molybdenum or molybdenum is also known.

The adhesive strength characteristics obtained from these copper foils are as follows:
Although the characteristics peculiar to the metal components in each layer are exerted and the effect of suppressing deterioration after immersion in hydrochloric acid for a long time after heat treatment is low, there is a drawback that the deterioration tends to increase after immersion in an alkaline solution such as an aqueous solution of potassium cyanide. is there.

Further, it is strongly desired that the copper foil for printed circuit is excellent not only in adhesive strength characteristics but also in electrical characteristics. Regarding this, it is one of the electrical characteristics because the circuit width and spacing of copper foil, which is the conductor of the printed wiring board, becomes narrower and finer, and especially the thickness of the resin insulation layer becomes thinner. Excellent migration resistance is an important requirement.

For example, in a metal base printed wiring board using a metal base such as an aluminum plate or an iron plate as a substrate, a thin insulating layer such as a resin insulating layer is provided between the metal base and the copper foil. When a copper foil having the formation layer of the prior art is used for such a wiring board, the interlayer insulating property between the metal base and the copper foil is not sufficient due to the thin insulating layer, which may cause migration. It has the drawback that it progresses quickly. In particular, in the wiring board using the copper foil proposed in Japanese Patent Publication No. 2-24037, the insulation performance is remarkably deteriorated due to the migration, and the reliability of the insulation characteristics is significantly deteriorated. Further, the copper foil having nickel and molybdenum layers disclosed in Japanese Patent Publication No. 62-142389 has room for improvement as well.

The term "migration" as used herein means that when a potential difference occurs between circuits of a printed wiring board or between layers, when moisture or water intervenes, the copper foil serving as a circuit is ionized and eluted, and the eluted copper ions are generated. It is a dendritic growth that is reduced over time into a metal or compound state. Then, when this reaches the other metal body and adheres thereto, a very fatal defect in terms of quality, that is, a defect such as a short circuit is caused. This is the occurrence of a short circuit accident due to so-called copper ion migration.

Originally, in order to prevent such a situation, the polymeric insulating resin or the base material to be laminated and adhered to the copper foil should not absorb moisture at all, or the environment should be such as to prevent the mixing of water. It is desirable to keep
At present, such a thing is extremely difficult.

On the other hand, a copper foil having a copper alloy layer showing a relatively good tendency in migration resistance is also disclosed. For example, a copper foil having a brass layer (copper-zinc alloy layer) on the copper foil surface (Japanese Patent Publication No. 51-35711) is also known. In the case of this copper foil, although various required properties of adhesive strength are substantially satisfied, there is still room for improvement. Regarding migration resistance, this brass layer is an alloy of copper and zinc containing copper as one of the main components, and since there are no measures to prevent migration of copper ions,
It is expected that no improvement in insulation performance can be expected. in addition,
This brass layer is formed by electrodeposition using a plating bath containing a cyanide compound, and for the sake of safety and health, there is a high risk of pollution, and obstacles to the characteristics and manufacturing of copper foil have not been overcome. .

[0015]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks of the prior art, maintain a high adhesive strength between a copper foil and a resin substrate, and to provide a copper foil for a printed circuit which is excellent in migration resistance. To provide. Another object of the present invention is to provide a method for manufacturing this copper foil for printed circuits.

[0016]

As a result of various investigations by the present inventors in order to solve the above-mentioned drawbacks of the prior art, the present invention has been completed.

That is, the present invention provides a copper foil for a printed circuit, comprising a ternary alloy coating layer made of nickel, molybdenum and cobalt on the surface of the copper foil.

The present invention also provides a printed circuit copper foil having a chromate treatment layer on the ternary alloy coating layer, and a chromate treatment layer and a silane coupling agent treatment layer on the ternary alloy coating layer in this order. A copper foil for a printed circuit is provided.

The copper foil for a printed circuit according to the present invention will be described in detail below.

The copper foil applied to the present invention is mainly electrolytic copper foil,
It is a rolled copper foil. In addition, the surface is made of aluminum or plastic film by electroplating, electroless plating, vacuum deposition, sputtering, etc.
It may be a composite foil provided with an ultrathin copper layer having a thickness of about 0 μm.

It is desirable to use a copper foil having a rough surface formed on at least one surface of the copper foil in advance by using an electrochemical or mechanical means. The copper foil for a printed circuit is molded into a copper clad laminate by heating and pressurizing it with a resin base material described later. By using a copper foil having a rough surface, the adhesive strength between the copper foil and the resin substrate is improved.

On the other hand, although the thickness of the copper foil is not particularly limited, it is usually 3 to 70 μm. Depending on the application, it is possible to use foils with a thickness of more than 70 μm.
It can be appropriately selected.

The copper foil for a printed circuit according to the present invention has a ternary alloy coating layer made of nickel, molybdenum and cobalt (hereinafter abbreviated as Ni-Mo-Co layer) on at least one surface of the copper foil. . This Ni-Mo-Co layer does not impair the state where the copper foil surface is roughened in advance, in other words, it is possible to sufficiently exert the adhesive strength with the resin base material generated from the anchoring effect brought about by the roughened surface formation. It is preferable to use a thin layer having a thickness that allows it. The preferred thickness is
It is 0.001 to 0.03 μm. The Ni-Mo-Co layer has excellent chemical resistance and can reduce the decrease in adhesive strength, that is, the deterioration rate even when immersed in an aqueous solution of hydrochloric acid or potassium cyanide. It also has excellent heat resistance and is a component that can prevent the deterioration of its adhesive strength even if it is held at high temperature for a long time. In particular, nickel is a component that exhibits an excellent effect of improving migration resistance.

The preferred range of the content of each metal in the Ni-Mo-Co layer is as follows: nickel 30 to 1200 μg / dm ² molybdenum 30 to 1000 μg / dm ² and cobalt 30 to 1000 μg / dm ² .

Here, the function of each metal component will be described. Since the Ni-Mo-Co layer is a ternary alloy layer,
It is clear that the effect brought by this layer is a synergistic effect of each metal component, and the amount of each metal component and its influence cannot be unequivocally limited, but according to various trial experiments, , Which is considered as follows.

When the metal content of nickel in the Ni-Mo-Co layer is less than 30 μg / dm ² , the effect of mainly preventing migration is attenuated and the insulation performance may be deteriorated. On the other hand, when it exceeds 1200 μg / dm ² , it may be related to the amount of components other than nickel, but may cause a disadvantage that it is not dissolved in a general-purpose etching solution within a predetermined time during etching.

Molybdenum has a metal content of 30 μg /
When it is less than dm ^2, the deterioration rate of the adhesive strength after heating for a long time may be large, and when it exceeds 1000 μg / dm ² , the deterioration rate of the adhesive strength after dipping in alkali resistance, for example, potassium cyanide aqueous solution becomes large. , It may hinder practical use.

Cobalt has a metal content of 30 μg / d
If it is less than m ^2, the deterioration rate of the adhesive strength after a long-time heat treatment may be large, and if it exceeds 1000 μg / dm ² , deterioration of the adhesive strength after a long-time heat treatment or a chemical treatment may occur. It may increase the production cost from the economical point of view.

By keeping the metal contents of the three components within the above ranges, Ni-Mo-Co which is particularly excellent in the effect of improving the adhesive strength and preventing migration, which cannot be achieved by the conventional binary alloy layer and the like. A layer is obtained. Particularly preferred Ni-Mo-
The ranges of the metal content of the Co layer are nickel 60 to 1000 μg / dm ² molybdenum 60 to 600 μg / dm ² and cobalt 60 to 600 μg / dm ² .

The Ni-Mo-Co layer containing these three kinds of metals in the above preferable range or particularly preferable range was analyzed by an ESCA analyzer, and the oxide and hydroxide of each metal were found in the outermost layer. Although some are found, it has been confirmed that the lower layer, which occupies most of them, has an alloy structure composed of nickel, molybdenum and cobalt. It is also known that the thickness is about 0.001 to 0.03 μm. Further, the appearance hue of this layer varies depending on the metal content which varies depending on the selection of the bath composition and the electrolysis conditions of the production method for obtaining the copper foil of the present invention described below and the rough surface forming state of the copper foil, but it is reddish brown to brown. ~ Observed as brown to off-brown.

The present invention further provides a printed circuit copper foil having a chromate treatment layer on the Ni-Mo-Co layer and a copper foil for a printed circuit having a silane coupling agent treatment layer on the chromate treatment layer. It is provided.

These copper foils for printed circuits according to the present invention will be described. When a chromate-treated layer is provided on the Ni-Mo-Co layer, the effect of simultaneously improving the rust-preventing property and the adhesive strength, and the alkaline solution or acid. The effect of reducing the deterioration rate of the adhesive strength of the chemical resistance after being immersed in the liquid is also obtained.
Further, when the silane coupling agent-treated layer is provided on the chromate-treated layer, the adhesive strength characteristics can be dramatically improved, and the quality reliability of the copper foil for printed circuit can be significantly improved.

This chromate-treated layer is composed of chromium oxide and chromium hydroxide, and the preferable range of the metal content measured with chromium as the metal is 10 to 90 μg / dm.
² , particularly preferably in the range of 30 to 60 μg / dm ² .

The silane coupling agent-treated layer is obtained by coating and drying an aqueous solution of a silane coupling agent, which will be described later, diluted with a predetermined amount of water or the like, preferably 0.001 to 5% (weight). In view of the improvement of the adhesive property and the economical efficiency, a silane coupling agent-treated layer coated and dried from an aqueous solution of 0.01 to 3% (by weight) is particularly preferable.

Next, the method for producing a copper foil for a printed circuit according to the present invention will be described. The feature is that the copper foil is immersed in a plating bath in which nickel ions, molybdate ions and cobalt ions coexist, and the cathode is used. The treatment is to form a ternary alloy coating layer made of nickel, molybdenum, and cobalt on at least one copper foil surface.

The present invention also provides a method for producing a copper foil for a printed circuit, which comprises subjecting the coating layer to a cathodic treatment in an aqueous solution containing hexavalent chromium ions to form a chromate-treated layer, and further the chromate-treated layer. The present invention also provides a method for producing a copper foil for a printed circuit, which further has a silane coupling agent treatment layer formed thereon.

The method for producing a copper foil for a printed circuit according to the present invention will be described in detail below. Using the copper foil material described above,
If necessary, a rough surface is formed in advance. For example, using electrolytic copper foil, copper sulfate plating bath, copper pyrophosphate plating bath,
Immersed in copper sulfamate plating bath, copper citrate plating bath, etc., and subject at least one surface of the copper foil to cathodic treatment,
A so-called roughened copper foil, which is obtained by electrodeposition-forming dendritic to granular copper particles as needed on the copper foil surface, is prepared. Then, a Ni-Mo-Co layer is formed on the rough surface of the copper foil.

In producing the copper foil for a printed circuit of the present invention, an electroplating method, a chemical plating method, a vapor deposition method, a sputtering method, a metallikon method or the like can be used for forming the Ni—Mo—Co layer. However, among these, the method of the present invention, which is carried out by cathodic electrolysis by electroplating, is practically advantageous in terms of mass productivity and economical efficiency.

The manufacturing method of the present invention is carried out by electrodeposition using this electroplating method. Therefore, the plating bath is first constructed.

Examples of the plating bath include an aliphatic oxyacid bath such as garnetic acid, glycolic acid, lactic acid, citric acid and malic acid, a gluconic acid bath, a sulfamic acid bath and a pyrophosphoric acid bath. Among them, citric acid bath is preferably applied considering bath management, environmental problems, wastewater treatment and the like.

Explaining the case of using a citric acid bath, citric acid and sodium salts, potassium salts of citric acid,
Select at least one of ammonium salts,
It is used by dissolving it in a prescribed amount of water. The amount used is 10-100
The range of g / l, preferably 10 to 50 g / l is desirable from the viewpoint of electrodeposition formation and economy.

As described above, the metal ion sources coexisting with these are the three types of nickel ions, molybdate ions and cobalt ions. Examples of chemical agents that can be used as the respective metal ion source are nickel sulfate. , Nickel chloride, nickel carbonate, nickel acetate, nickel formate and the like.

As the molybdate ion source, sodium molybdate, potassium molybdate, ammonium molybdate, etc. can be used.

As a cobalt ion source, cobalt sulfate,
Cobalt acetate, cobalt sulfamate, cobalt chloride, diammonium cobalt sulfate, cobalt gluconate and the like can be used.

Each of these ion source chemicals is dissolved in a predetermined amount of water and used as a plating bath for electrodepositing the Ni-Mo-Co layer.

A copper foil is dipped in this plating bath and subjected to cathodic electrolysis to form a Ni-Mo-Co layer. Preferred examples of the plating bath composition, electrolysis conditions, etc. are as follows.
The range in () indicates a particularly preferable range.

Nickel Sulfate Hexahydrate 1-100 g / l (5-50 g / l) Sodium Molybdate Dihydrate 0.5-20 g / l (1-10 g / l) Cobalt Sulfate Heptahydrate Material 0.5 to 100 g / l (1 to 50 g / l) Trisodium citrate dihydrate 10 to 100 g / l (20 to 50 g / l) Bath temperature 10 to 80 ° C (20 to 40 ° C) pH 3 ~ 7 (4 to 6.5) Cathode current density 1 to 20 A / dm ² ( ^{2 to} 10 A / dm ² ) Electrolysis time 1 to 60 seconds (1 to 10 seconds) Anode platinum-based insoluble anode Cathode Electrolytic copper foil or rolled copper Foil

The range of each metal content of the Ni-Mo-Co layer is as described above, and it is important to keep it within the range. Therefore, the increase / decrease adjustment to keep the metal content of the Ni-Mo-Co layer appropriate is usually done by the amount of each metal ion in the plating bath (concentration of each chemical), cathode current density, voltage, electrolysis time, pH, bath temperature. , Stirring and the like are appropriately changed. For this reason, the quantitative determination of each metal content in the Ni-Mo-Co layer and the metal component in the plating bath should be carried out regularly, and if necessary, the supplement of the metal component in the plating bath and the appropriate selection of electrolysis conditions should be selected. It is desirable to carry out the above in order to mass produce the copper foil of the present invention.

In carrying out the manufacturing method for forming the Ni—Mo—Co layer of the present invention, for example, a coiled copper foil having a predetermined thickness and width is arranged as necessary. A copper foil comprising a de-fingering bath, a pickling bath, a water washing bath and a surface-roughened copper plating bath, a plating bath for forming a Ni-Mo-Co layer next to the washing bath, a washing bath, and a drying device. It is preferable that the processing is carried out at a constant speed in the processing apparatus and continuously wound into a coil to manufacture.

Further, in the method of the present invention, the formation of the chromate-treated layer or the chromate-treated layer and the silane coupling agent-treated layer on the Ni-Mo-Co layer is Ni-M in any case.
After forming the o-Co layer, washing is performed with water.

Specifically, first, the formation of the chromate-treated layer is performed using an aqueous solution containing hexavalent chromium ions. The chromate layer can be formed only by dipping,
Preference is given to carrying out according to the method of the invention by cathodic treatment. The plating bath composition and electrolysis conditions at this time are exemplified as follows. The range in () indicates a particularly preferable range.

Sodium dichromate 0.1 to 50 g / l (1 to 5 g / l) or chromic acid, potassium chromate pH (adjusted with sulfuric acid or caustic soda) 1 to 13 (3 to 12) bath temperature 0 to 60 ° C (10 to 40 ° C) Cathode current density 0.1 to 50 A / dm ² (0.2 to 5 A / dm ² ) Electrolysis time 0.1 to 100 seconds (1 to 10 seconds)

By the above operation, a chromate-treated layer is formed on the Ni-Mo-Co layer, and this is dried to produce the copper foil of the present invention.

According to still another method of the present invention, after forming the chromate-treated layer, it is washed with water, and then the silane coupling agent-treated layer is formed on the chromate-treated layer. Examples of the silane coupling agent used for forming the silane coupling agent-treated layer include those described in Japanese Patent Publication No. 60-15654 previously proposed by the present applicant, such as 3-aminopropyltriethoxysilane and 3-glycidoxy. Examples thereof include propyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane and the like. At least one of these silane coupling agents is selected and used as an aqueous solution. The concentration is usually 0.
It is used in a concentration of 001 to 5% by weight, preferably 0.01 to 3% by weight. This aqueous solution is applied to the chromate-treated layer by spraying, dipping or the like. After applying,
If it is dried, the copper foil of the present invention in which a chromate treatment layer and a silane coupling agent treatment layer are sequentially formed on the Ni-Mo-Co layer is manufactured.

By forming the chromate-treated layer and the silane coupling agent-treated layer, the improvement of the adhesive strength characteristics, which is the object of the present invention, can be further enhanced. Incidentally, if necessary for the plating bath for forming the chromate treatment layer, zinc ions, molybdate ions, etc. are added to the plating bath.
It is also possible to coexist 1 to 10 g / l and perform cathodic treatment under the above electrolysis conditions to form a chromate-treated layer containing zinc or molybdenum.

The copper foil obtained by the method of the present invention is laminated with a resin substrate as a copper foil for a printed circuit in the production of various copper clad laminates. Applicable resins include epoxy, phenol, polyimide and Saturated polyester, thermosetting resin such as silicon, polyethylene, saturated polyester, thermoplastic resin such as polyether sulfone, as the substrate, paper, glass, glass cloth, glass woven cloth, polyimide / polyester film, etc., or aluminum, Examples include those based on a metal plate such as iron.

[0057]

EXAMPLES The present invention will be described in detail below with reference to examples.

Example 1 An electrolytic copper foil having a thickness of 35 μm was immersed in a copper sulfate plating bath, and granular copper was electrodeposited on one surface of the copper foil in advance by cathodic electrolysis to form a rough surface. Using this copper foil, a plating bath having the following composition as shown in Table 1 was prepared. Trisodium citrate (Na ₃ C ₆ H ₅ O ₇ · 2H ₂ O) 30 g / l Nickel sulfate (NiSO ₄ · 6H) ₂ O) 30 g / l Sodium molybdate (Na ₂ MoO ₄ · 2H ₂ O) 3 g / l Cobalt sulfate (CoSO ₄ · 7H ₂ O) 7 g / l Copper foil was immersed, electrolysis conditions were pH 6.0, bath temperature Thirty
Cathodic electrolysis was carried out at a temperature of 2 ° C., a current density of 2 A / dm ² , and an electrolysis time of 8 seconds to form a Ni—Mo—Co layer on the rough surface. Immediately after washing with water, sodium dichromate (Na ₂ Cr ₂ O ₇ · 2H ₂ O) 3.5 g /
The pH of the aqueous solution was adjusted to 5.7 and the temperature was 26 ° C., and the obtained copper foil was dipped in the solution and subjected to cathodic electrolysis at a current density of 0.5 A / dm ² and an electrolysis time of 5 seconds on the Ni-Mo-Co layer A chromate-treated layer was formed on. After sufficiently washing this copper foil with water, a 0.15% (weight) aqueous solution of 3-glycidoxypropyltrimethoxysilane (liquid temperature 25 ° C.) was applied onto the chromate-treated layer by spraying, and the drying temperature was immediately 100 ° C. For 5 minutes to produce a copper foil of the present invention in which a Ni-Mo-Co layer, a chromate treatment layer and a silane coupling agent treatment layer were sequentially formed on the rough surface side of the copper foil.

Quantitative analysis of the metal content of the adhered component formed on the copper foil surface using this copper foil as a test piece was carried out by an ICP analyzer, and as shown in Table 1, nickel 500 μg / dm ² molybdenum 260 μg / dm ² cobalt was 290 μg / dm ² .

The chromium metal content is 40 μg / dm
^{Was 2} . Next, this copper foil was combined with FR-4 grade epoxy resin-impregnated glass base material, temperature 168 ° C., pressure 38 kg /
cm ² was laminated to produce a copper clad laminate.

The copper-clad laminate was subjected to the following tests, and the results are shown together in Table 1. 1. Adhesive strength test (Peeling width 1mm, JIS C
6481) Normal state ----- Adhesive strength after lamination [a (kgf / c
m)] Deterioration rate after immersion in hydrochloric acid ---- 6N hydrochloric acid aqueous solution (temperature 2
Adhesive strength [b (k
gf / cm)], and the deterioration rate (%) = {(ab))
/ A} × 100. Deterioration rate after immersion in potassium cyanide -------- Adhesive strength [c (kgf / cm)] after being immersed in a 10% aqueous solution of potassium cyanide (temperature 70 ° C) for 0.5 hour was measured, and deterioration rate (%) = It is shown by {(a−c) / a} × 100. Deterioration rate after heat treatment Adhesive strength [d (kgf / cm)] after being kept in a water bath at a temperature of 177 ° C for 240 hours was measured, and the deterioration rate (%)
It is shown by {(ad) / a} × 100. Deterioration rate after boiling treatment Adhesive strength after being held in boiling water for 2 hours [e (kgf /
cm)], and the deterioration rate (%) = {(a−e) / a}
It was shown by × 100.

2. Heat discoloration test of copper foil removal surface Copper clad laminate was immersed in an etching solution (cupric chloride) to remove the copper foil, washed with water, and then held in a thermostatic chamber at a temperature of 160 ° C. for 2 hours. The presence or absence of discoloration on the foil-removed surface was observed.
○ Good × discoloration 3. Migration resistance test Using the apparatus shown in FIG. 1, a copper foil test piece 1 folded in two so that each treatment layer formed on the rough surface is on the outside was used as an anode, and an iron plate 2 was used as a cathode. After adjusting the gap to 2 mm, sandwich the glass plate 3 from both sides and put distilled water 4 in the gap.
Then, a constant voltage (20 V) was applied between both electrodes, and the time (second) until the current increased was measured. It is shown that the earlier the current rises, the faster the migration progresses, and that the insulation performance deteriorates significantly.

Example 2 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolytic conditions shown in Table 1 were used.
After the Ni-Mo-Co layer was formed, it was washed with water and dried as in Example 1. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolysis conditions shown in Table 1 were used.
After forming a Ni-Mo-Co layer and washing with water, a chromate-treated layer similar to that in Example 1 was formed, washed with water and dried. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolytic conditions shown in Table 1 were used.
After the Ni-Mo-Co layer was formed, it was washed with water and dried as in Example 1. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 5 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolytic conditions shown in Table 1 were used.
After forming a Ni-Mo-Co layer and washing with water, a chromate-treated layer was formed and washed with water in the same manner as in Example 1. Thereafter, the same operation as in Example 1 was performed except that a 0.08% (weight) aqueous solution of 3-mercaptopropyltrimethoxysilane was used to form the silane coupling agent-treated layer. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 6 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolytic conditions shown in Table 1 were used.
After forming a Ni-Mo-Co layer and washing with water, a chromate-treated layer was formed in the same manner as in Example 1 and washed with water. Thereafter, the same operation as in Example 1 except that 0.3% (weight) of N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane was used to form the silane coupling agent-treated layer. I went. Example 1 using the obtained copper foil as a test piece
The metal content measurement and the characteristic test were carried out in the same manner as in, and the results are shown in Table 1.

Example 7 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolysis conditions shown in Table 1 were used.
After forming a Ni-Mo-Co layer and washing with water, a chromate-treated layer was formed in the same manner as in Example 1 and washed with water. Thereafter, the same procedure as in Example 1 was carried out except that a 0.5% (weight) aqueous solution of N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane was used to form the silane coupling agent-treated layer. The operation was performed. Using the obtained copper foil as a test piece, a metal content measurement and a characteristic test were carried out in the same manner as in Example 1,
The results are shown in Table 1.

Example 8 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolytic conditions shown in Table 1 were used.
After forming a Ni-Mo-Co layer and washing with water, a chromate-treated layer was formed in the same manner as in Example 1, followed by washing with water and drying. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 9 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolytic conditions shown in Table 1 were used.
After the Ni-Mo-Co layer was formed, it was washed with water and dried as in Example 1. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 10 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolysis conditions shown in Table 1 were used.
After forming a Ni-Mo-Co layer and washing with water, a chromate-treated layer was formed in the same manner as in Example 1 and washed with water. After that, the same operation as in Example 1 was performed except that a 0.15% (weight) aqueous solution of 3-glycidoxypropyltrimethoxysilane was used to form the silane coupling agent-treated layer. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 11 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolytic conditions shown in Table 1 were used.
After forming a Ni-Mo-Co layer and washing with water, a chromate-treated layer was formed in the same manner as in Example 1 and washed with water. After that, the same operation as in Example 1 was performed except that a 0.1% (weight) aqueous solution of 3-aminopropyltriethoxysilane was used to form the silane coupling agent-treated layer. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 12 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the plating bath composition and electrolysis conditions shown in Table 1 were used.
After forming a Ni-Mo-Co layer and washing with water, a chromate-treated layer was formed in the same manner as in Example 1 and washed with water. After that, the same operation as in Example 1 was performed except that a 0.3% (weight) aqueous solution of 3-glycidoxypropyltrimethoxysilane was used to form the silane coupling agent-treated layer. Using the obtained copper foil as a test piece, metal content measurement and characteristic test were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the rough surface of the copper foil was plated bath composition: sodium cyanide 50 g / l sodium hydroxide 60 g / l cyan Copper oxide 90 g / l Zinc cyanide 5 g / l Electrolysis conditions Current density 5 A / dm ² pH 12 Temperature 80 ° C. Electrolysis time is 10 seconds and cathodic electrolysis is performed to give a copper / zinc alloy layer (alloy ratio about copper 70,
After forming zinc 30) and washing with water, a chromate-treated layer was formed in the same manner as in Example 1, followed by washing with water and drying. Using the obtained copper foil as a test piece, a metal content (zinc only) and characteristic test were conducted in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 2 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the rough surface of the copper foil was plated bath composition: sodium cyanide 50 g / l sodium hydroxide 60 g / l cyan Copper oxide 90 g / l Zinc cyanide 5 g / l Electrolysis conditions Current density 5 A / dm ² pH 12 Temperature 80 ° C. Electrolysis time 10 seconds After cathodic electrolysis to form a copper-zinc alloy layer and washing with water, Similarly, a chromate treatment layer and a silane coupling agent treatment layer were sequentially formed and dried. Using the obtained copper foil as a test piece, a metal content (zinc only) and characteristic test were conducted in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 3 Using the same copper foil as in Example 1, the surface was roughened in the same manner as in Example 1, and the rough surface of the copper foil had a plating bath composition of NiSO ₄ .6H ₂ O 50 g / l Na ₂ MoO _4. 2H ₂ O 5 g / l Na ₃ C ₆ H ₅ O ₇ 2H ₂ O 30 g / l Electrolysis conditions pH 5.0 Temperature 30 ° C. Current density 2.0 A / dm ² Cathodic electrolysis with electrolysis time 4 seconds, nickel. Forming a molybdenum layer,
After washing with water, a chromate-treated layer was formed in the same manner as in Example 1, followed by washing with water and drying. Using the obtained copper foil as a test piece, a metal content and characteristic test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 4 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the rough surface of the copper foil was plated bath composition NiSO ₄ .6H ₂ O 50 g / l Na ₂ MoO ₄ 2H ₂ O 7 g / l Na ₃ C ₆ H ₅ O ₇ 2H ₂ O 30 g / l Electrolysis conditions pH 5.0 Temperature 30 ° C. Current density 2.0 A / dm ² Cathodic electrolysis with electrolysis time 4 seconds, After forming a nickel-molybdenum layer and washing with water, a chromate treatment layer and a silane coupling agent treatment layer were sequentially formed in the same manner as in Example 1 and dried. Using the obtained copper foil as a test piece, a metal content and characteristic test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 5 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the rough surface of the copper foil had a plating bath composition of NiSO ₄ .6H ₂ O 60 g / l Na ₂ MoO _4. 2H ₂ O 10 g / l Na ₃ C ₆ H ₅ O ₇ 2H ₂ O 30 g / l Electrolysis conditions pH 5.0 Temperature 30 ° C. Current density 2.0 A / dm ² Cathodic electrolysis with electrolysis time of 8 seconds and copper After the zinc alloy layer was formed and washed with water, a chromate treatment layer and a silane coupling agent treatment layer were sequentially formed in the same manner as in Example 1 and dried. Using the obtained copper foil as a test piece, a metal content and characteristic test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 6 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the rough surface of the copper foil was plated bath composition CoSO ₄ .7H ₂ O 30 g / l Na ₂ MoO ₄・ 2H ₂ O 1 g / l Na ₃ C ₆ H ₅ O ₇・ 2H ₂ O 30 g / l Electrolysis conditions pH 5 Temperature 30 ° C. Current density 2 A / dm ² Cathodic electrolysis with electrolysis time 4 seconds to form a cobalt-molybdenum layer. Formed,
After washing with water, a chromate-treated layer was formed in the same manner as in Example 1, followed by washing with water and drying. Using the obtained copper foil as a test piece, a metal content and characteristic test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 7 Using the same copper foil as in Example 1, the surface was roughened in the same manner as in Example 1, and the rough surface of the copper foil had a plating bath composition of CoSO ₄ .7H ₂ O 40 g / l Na ₂ MoO _4.・ 2H ₂ O 3 g / l Na ₃ C ₆ H ₅ O ₇・ 2H ₂ O 30 g / l Electrolysis conditions pH 5 Temperature 30 ° C. Current density 2 A / dm ² Cathodic electrolysis with electrolysis time 6 seconds, cobalt-molybdenum layer Formed,
After washing with water, a chromate treatment layer and a silane coupling agent treatment layer were sequentially formed and dried as in Example 1. Using the obtained copper foil as a test piece, a metal content and characteristic test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 8 Using the same copper foil as in Example 1, surface roughening was performed in the same manner as in Example 1, and the rough surface of the copper foil was plated bath composition CoSO ₄ .7H ₂ O 7 g / l Na ₂ MoO ₄ 2H ₂ O 10 g / l Na ₃ C ₆ H ₅ O ₇ 2H ₂ O 30 g / l Electrolysis conditions pH 5 Temperature 30 ° C. Current density 2 A / dm ² Cathodic electrolysis with electrolysis time 8 seconds, cobalt-molybdenum layer Formed,
After washing with water, a chromate treatment layer and a silane coupling agent treatment layer were sequentially formed and dried as in Example 1. Using the obtained copper foil as a test piece, a metal content and characteristic test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 9 A copper foil similar to that of Example 1 was used, and the surface roughness was similar to that of Example 1.
And then sodium dichromate (Na₂C r₂O₇・ 2H
₂O) 3.5 g / l aqueous solution as a plating bath, pH 5.7,
Liquid temperature 26 ° C, current density 0.5A / dm², Electrolysis time 5 seconds
Cathodic electrolysis under the conditions of, and chromate treatment on the rough surface of copper foil
After forming the layer, it was washed with water and dried. The obtained copper foil
As a test piece, metal content and characteristic test as in Example 1
Was carried out and the results are shown in Table 2.

Comparative Example 10 A copper foil similar to that of Example 1 was used and the surface roughness was similar to that of Example 1.
The surface of the copper foil, and then add sodium dichromate (Na₂
C r₂O₇・ 2H₂O) 3.5g / l aqueous solution as a plating bath, pH
5.7, Liquid temperature 26 ° C, Current density 0.5A / dm²,electrolytic
Perform cathodic electrolysis under the condition of time of 5 seconds and chrome on the rough surface of copper foil.
A coating layer was formed. After washing with water, 3-glyc
Doxypropyltrimethoxysilane 0.15% (weight)
Apply the aqueous solution with a shower at a liquid temperature of 25 ° C and dry immediately.
Chromate the copper foil surface by drying at a drying temperature of 100 ° C for 5 minutes
Copper foil with treatment layer and silane coupling agent treatment layer
Was manufactured. This copper foil was used as a test piece in the same manner as in Example 1.
A metal content and characteristic test was conducted, and the results are shown in Table 2.
did.

[0084]

[Table 1]

[0085]

[Table 2] A: Adhesive strength after lamination B: Degradation rate after dipping in hydrochloric acid C: Degradation rate after dipping in potassium cyanide D: Degradation rate after heat treatment E: Degradation rate after boiling treatment F: Migration resistance G: Copper foil removed surface Example of heat discoloration of copper foil having Ni-Mo-Co layer formed only on the copper foil surface (Examples 2, 4, 9), and example of copper foil having chromate treatment layer formed thereon (Examples 3, 8) ) And a chromate-treated layer on which a silane coupling agent-treated layer is further formed (Examples 1, 5, 6, 7, 10, 11, 12) are representative examples of the present invention. is there. Of these, Examples 2, 4, 9
Although the adhesive strength in the normal state is slightly lower than those of the other Examples, the value remains at a practical level. Furthermore,
Similar to the other examples, the deterioration rate of the adhesive strength after dipping in hydrochloric acid or an aqueous solution of potassium cyanide is suppressed to be small. Further, it is understood that the anti-migration property, which is also one of the electrical characteristics, is excellent, and the deterioration of the insulating property caused by the migration phenomenon of copper ions can be prevented for a long time. Due to these excellent required characteristics, the copper foil for a printed circuit according to the present invention can withstand use in a bad environment of high temperature and high humidity and maintain good quality reliability. It is considered that each of the above-mentioned metal properties of nickel, molybdenum and cobalt or alloy properties brought about by their synergistic action are involved in the improvement of these properties, and further by a chromate treatment layer or a silane coupling agent treatment layer. It is considered that the effect is further brought out.

In contrast, in Comparative Examples 1 to 8 of the copper foil from the prior art forming the binary alloy layer, it has been shown that it is difficult to simultaneously satisfy the required characteristics of different qualities as described. . That is, Comparative Example 1 shows that the deterioration rate after boiling is large and hinders practical use, and Comparative Example 2 shows that
It also has low migration resistance. In Comparative Examples 3, 4, and 5,
The deterioration rate after immersion in an aqueous solution of potassium cyanide is large, and there is a problem with the heat discoloration of the copper foil removal surface after etching.
It is recognized that the migration resistance also needs to be improved depending on the component amounts. Comparative Examples 6, 7, and 8 have a large deterioration rate after immersion in an aqueous solution of potassium cyanide, and much improvement in migration resistance is required. Further, the ternary alloy coating layer comprising the Ni—Mo—Co layer of the present invention has a relatively small thickness (μg / dm ² ) (Example 11).
It is understood that the effects such as the adhesive strength and the migration resistance are enhanced as compared with Comparative Examples 1 to 8. On the other hand, Comparative Examples 9 and 10 are examples in which neither the Ni-Mo-Co layer nor the conventional alloy layer was formed.
It can be seen that the migration resistance and the heat discoloration of the copper foil-removed surface are significantly inferior to the copper foil for printed circuit of the present invention.

[0087]

As described in detail above, the copper foil for a printed circuit according to the present invention has a ternary alloy coating layer made of nickel, molybdenum and cobalt on the surface of the copper foil. When laminated with a resin base material to form a copper clad laminate, it maintains good adhesive strength between the copper foil and the resin base material even during severe conditions due to heat and chemicals as well as during lamination Above all very useful. In addition, the copper foil for a printed circuit of the present invention is excellent in migration resistance and greatly contributes to the improvement of the insulating characteristics of the printed circuit.

By further forming a chromate-treated layer, or a chromate-treated layer and a silane coupling agent-treated layer on the above ternary alloy coating layer, adhesiveness further excellent in heat resistance and chemical resistance can be obtained. To be

Therefore, in recent years, the number of layers has increased, the density has increased,
In marked printed wiring boards, the copper foil of the present invention sufficiently satisfies the required properties required for printed circuit copper foils such as heat resistance, chemical resistance, migration resistance, etc. It can be suitably used as a copper foil for the inner and outer layers of the plate.

In addition, in the method for producing the copper foil of the present invention, the basic production conditions such as bath composition and electrolysis conditions can be selected from a wide range, and it has the advantage of being extremely easy to manage. Its mass production is excellent on an industrial scale and its value is great.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a test apparatus used for examining migration resistance.

[Explanation of symbols]

 1 Copper foil test piece 2 Iron plate 3 Glass plate 4 Distilled water

Claims (6)

[Claims] 1. A copper foil for a printed circuit, which has a ternary alloy coating layer made of nickel, molybdenum and cobalt on the surface of the copper foil. 2. A copper foil for a printed circuit having a ternary alloy coating layer made of nickel, molybdenum and cobalt on the surface of the copper foil, and a chromate treatment layer on the coating layer. 3. A printed circuit having a ternary alloy coating layer made of nickel, molybdenum and cobalt on the surface of a copper foil, a chromate treatment layer on the coating layer and a silane coupling agent treatment layer on the chromate treatment layer. Copper foil. 4. A copper foil is immersed in a plating bath in which nickel ions, molybdate ions, and cobalt ions coexist and subjected to cathodic treatment to form a ternary alloy coating layer made of nickel, molybdenum, and cobalt on the copper foil surface. Method for producing copper foil for printed circuit. 5. A copper foil is immersed in a plating bath in which nickel ions, molybdate ions and cobalt ions coexist, and subjected to cathodic treatment to form a ternary alloy coating layer of nickel, molybdenum and cobalt on the copper foil surface. And then
A method for producing a copper foil for a printed circuit, comprising performing a cathodic treatment in an aqueous solution containing hexavalent chromium ions to form a chromate-treated layer on the coating layer. 6. A copper foil is immersed in a plating bath in which nickel ions, molybdate ions and cobalt ions coexist, and subjected to cathodic treatment to form a ternary alloy coating layer of nickel, molybdenum and cobalt on the copper foil surface. And then
Cathode treatment is performed in an aqueous solution containing hexavalent chromium ions to form a chromate-treated layer on the coating layer, and then a silane coupling agent aqueous solution is further applied on the chromate-treated layer to form a silane coupling agent-treated layer. A method of manufacturing a copper foil for a printed circuit, which comprises: