JP2002161394A - Method for manufacturing copper foil for micro wiring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a copper foil for micro wiring, which has fine surface roughness on a surface to be bonded, is uniformly roughened, has a high etching factor without lowering a bonding strength between the copper foil and a base resin material, and does not leave copper particles on the base material, to form micro wiring. SOLUTION: The method for manufacturing a copper foil for micro wiring comprises; forming a composite metal layer on the surface to be bonded of the copper foil, by electrolyzing it in a plating bath which contains copper ion, ion of metals selected from tungsten or molybdenum, ion of metals selected from nickel, cobalt, iron, or zinc, and chloride ion of 1-100 mg/l, at an electric current density of less than limiting current density of the bath; forming a dendritic copper electrodeposited layer on the composite metal layer, by electrolyzing it in a plating bath containing copper ion, at the electric current density of more than the limiting current density of the bath; and forming coarsened layer consisting of copper, by further electrolyzing it at the current density of less than the limiting current density of the bath to form knotty copper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a copper foil for fine wiring, and more particularly to a method for producing a copper foil having a small surface roughness, uniform roughness, and excellent etching properties. The present invention relates to a method for producing a copper foil for fine wiring, which enables high-density fine wiring and has high adhesive strength to a substrate.

[0002]

2. Description of the Related Art A copper foil for a printed wiring board is generally roughened in advance so that a bonding surface of a copper foil to be laminated on a resin base material can have a stronger bonding strength by some method. . The mainstream method applied as the roughening means is a plating method in the case of electrolytic copper foil. As the plating method, for example, there is a method disclosed in Japanese Patent Publication No. 53-39376. This method uses an acidic copper plating bath, using a copper raw foil as a cathode, first forming a dendritic copper electrodeposited layer by so-called kogashi plating on at least one surface to be bonded of the copper foil by a current not lower than the limiting current density, Further, a smooth copper electrodeposited layer (cube plating) is formed on the dendritic copper electrodeposited layer by a current less than the limiting current density on the layer to change the dendritic copper into a so-called bumpy copper. It is intended to obtain an increase in adhesive strength by using copper. By forming this bump-shaped copper, the copper foil surface is increased in specific surface area as compared to before the electrolytic treatment, and the anchor effect by the bump-shaped copper is exerted, whereby the adhesive strength between the resin substrate and the copper foil is increased. improves. When the copper raw foil on which the bump-shaped copper is formed is an electrolytic copper foil, one surface (rough surface side) generally has irregularities as compared with the other surface (glossy surface side), and the current mainly flows to the convex portions. It is easy to concentrate, and the bumpy copper is formed almost at the tip of the convex portion.

In recent years, with the spread of notebook personal computers, mobile phones, and the like, the circuit width and circuit interval of printed wiring boards incorporated therein have been significantly reduced in density and fine wiring to 100 μm or less. In addition, high Tg type FR-
Glass epoxy printed wiring boards using five materials are increasing. High Tg type epoxy resin is the same as conventional FR-
Although it has higher heat resistance than the four materials, the adhesive strength to the copper foil tends to be low. As a method of increasing the adhesive strength with the resin substrate, there is a method of increasing the roughness of the surface to be bonded of the copper foil. However, when the roughness of the rough surface is increased, the so-called copper powder phenomenon in which the bump-like copper falls off even with a small frictional force or the residual bump-like copper remaining in the resin base material after the etching step performed at the time of producing a printed circuit. Copper phenomenon is likely to occur.

[0004] As means for improving these, Japanese Patent Publication No. Sho 54
JP-A-38053 discloses a rough surface forming method in which one or two or more selected from arsenic, antimony, bismuth, selenium, and tellurium are added to an acidic copper plating bath in a specific amount, and electrolytic treatment is performed before and after the limit current density. is there. Although minute projections are formed by adding a small amount of arsenic, antimony, bismuth, selenium, and tellurium, the phenomenon of concentration on the projections of the raw copper foil is not improved. Furthermore, when a copper foil containing arsenic, antimony, bismuth, selenium, and tellurium, which are toxic substances and deleterious substances, is used for a printed wiring board, a problem of environmental pollution occurs at the time of discarding the etching waste liquid or the printed wiring board itself. .

A method of adding benzoquinoline to an acidic copper plating bath (Japanese Patent Publication No. 56-41196) and a method of adding molybdenum (Japanese Patent Publication No. 62-56677) are disclosed. Was not sufficiently obtained.

[0006] As a method for further improving this problem, Japanese Patent Application Laid-Open No. 8-236930 discloses that at least one metal ion selected from chromium and tungsten and one selected from vanadium, nickel, iron, cobalt, zinc, germanium and molybdenum. A method is disclosed in which an electrolytic copper plating bath containing at least one type of metal ion is used to electrolyze near a critical current density to form a roughened layer containing an additional metal.
Also, Japanese Patent Application Laid-Open No. 11-256389 describes that molybdenum and one selected from iron, cobalt, nickel, and tungsten are used.
A method is disclosed in which an acidic copper plating bath containing at least one kind of metal ion is used to electrolyze near a critical current density to form a burnt plating layer (kogashi plating layer) containing an additional metal.

However, even when these methods are used, the bumpy copper tends to be formed at the tip of the convex portion of the raw copper foil, so that the copper powder dropping phenomenon and the residual copper phenomenon still occur.

[0008] An etching factor (Ef) is used as a measure of the etching characteristics of a copper clad laminate. FIG. 1 is a schematic sectional view of a circuit copper foil for explaining an etching factor (Ef), wherein B is an electrically insulating base material, and A is a circuit copper foil formed by etching a copper foil thereon. is there. Assuming that the top width of the circuit copper foil is WT, the bottom width of the circuit copper foil is WB, and the thickness of the circuit copper foil is H, Ef
= 2H / (WB-WT). The larger the value is, the more the side wall of the formed circuit pattern is close to vertical, indicating that when a fine wiring is to be formed,
It is desirable to select a copper foil having as large an Ef value as possible.

The Ef value is determined by the thickness of the copper foil, the surface roughness of the surface to which the copper foil is to be adhered, and the like. Since it is necessary to completely remove the projections on the roughened surface of the foil by etching, a long time is required for etching, and the already formed circuit walls are further etched, thereby deteriorating the circuit shape and reducing the Ef value. In addition, if the projections on the roughened surface are not completely etched, copper particles remain on the base material side, and when the distance between the fine wirings is small, disconnection or poor insulation may be caused.

Therefore, a copper foil having uniform roughness on the surface to be bonded of the copper foil, small surface roughness, excellent etching characteristics, and excellent adhesive strength to the substrate is required as a copper foil for fine wiring. You.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a copper foil having a small surface roughness on the side to be bonded and a uniform roughness.
Provided is a method for manufacturing a copper foil for fine wiring, which has a high etching factor without lowering the adhesive strength between the copper foil and the resin base material and can form fine wiring without leaving copper particles on the base material side. Is to do.

That is, according to the present invention, a copper foil is used as a cathode,
(1) copper ions, (2) metal ions of at least one metal selected from tungsten and molybdenum, and (3) at least one metal selected from nickel, cobalt, iron and zinc on the surface to be bonded of the copper foil. Plating bath (A) containing 1 to 100 mg / l of metal ions and (4) chloride ions
By electrolysis at a current density lower than the limiting current density of the bath, so that at least one metal selected from (I) copper, (II) tungsten and molybdenum and (III) nickel, cobalt, iron and zinc A composite metal layer made of at least one metal selected from the group consisting of: a) a plating bath (B) containing copper ions on the composite metal layer at an electric current density higher than the limit current density of the bath; Forming a dendritic copper electrodeposition layer, and further performing electrolytic treatment at a current density lower than the limiting current density of the bath to form a rough copper layer, thereby providing a roughened layer made of copper. An object of the present invention is to provide a method for manufacturing a copper foil for wiring.

Here, the limiting current density of the bath means a current density accompanied by generation of hydrogen gas in a cathode reaction in which a metal and a metal compound are precipitated.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The copper foil (copper raw foil) used in the present invention is preferably mainly an electrolytic copper foil. May be formed. Further, the thickness of the copper foil and the roughness and form of the copper foil surface are not particularly limited. Further, the surfaces to be bonded of the copper foil may be both surfaces.

[0015] The adhesion amount of copper (I) to the surface to be adhered of the raw copper foil is preferably 1,000 to 10,000 µg / dm.
² , the amount of one or more metals selected from (II) tungsten and molybdenum is preferably 10 to 1,000.
μg / dm ² , more preferably 10 to 200 μg / d
m ² , (III) the adhesion amount of at least one metal selected from nickel, cobalt, iron and zinc is preferably 1 to 1,000 μg / dm ² , more preferably 5 to 3 μg / dm ² .
00 μg / dm ² , more preferably 10 to 50 μg / d
forming a composite metal layer of m ² .

The adhesion amount of at least one metal selected from nickel, cobalt, iron and zinc is 1 μg / dm.
When the value is less than ^{2, the} bumpy copper is not uniformly formed even when the bumpy copper is formed by the plating method, and tends to be formed concentrated on the protruding portion, and when it exceeds 1,000 μg / dm ^2. In the formation of a copper circuit, when unnecessary copper is removed by etching, the etching time of the plating layer tends to be extremely slow. The deposition amount of at least one metal selected from nickel, cobalt, iron and zinc is related to the composition of the plating bath and the setting of the treatment conditions, and is appropriately selected from the bath composition and electrolysis conditions described later. Is done.

The amount of copper deposited on the composite metal layer is 1,000
Located 0 Pg / dm uniform nodular copper throughout is less than ² is not formed tends, 10,000 [/ dm ² to more than the effect of forming uniform nodular copper throughout the small and the manufacturing cost increases Tend to. If the amount of one or more metals selected from tungsten and molybdenum of the composite metal layer is less than 10 μg / dm ² , a uniform copper-like copper tends not to be formed as a whole,
If it exceeds μg / dm ² , the bumpy copper tends not to increase. The thickness of the composite metal layer is preferably from 0.01 to 0.15 μm.

In the present invention, the composite metal layer is formed by using a copper foil as a cathode, (1) copper ions,
(2) metal ions of at least one metal selected from tungsten and molybdenum; (3) metal ions of at least one metal selected from nickel, cobalt, iron and zinc; and (4) 1 to 100 mg / chlorine ion This is carried out by using a plating bath (A) containing 1 and performing an electrolytic treatment at a current density lower than the limit current density of the bath. It is preferable that the surface to be bonded of the copper foil be subjected to pickling and degreasing in advance.

Each metal ion source of the plating bath (A) is selected from water-soluble metal salts and used. A preferred bath composition is preferably selected from the following ranges, but is not particularly limited. (1) Copper ion concentration: 5 to 25 g / l (copper ion source-copper sulfate pentahydrate) (2-1) Tungsten ion concentration: 0.006 to 11
g / l (tungsten ion source-sodium tungstate dihydrate) (2-2) Molybdenum ion concentration: 0.2 to 8 g / l
(Molybdenum ion source-sodium molybdate dihydrate) (2-3) Total concentration of tungsten ion and molybdenum ion; 0.006 to 11 g / l (3-1) Nickel ion concentration; 2 to 22 g / l (nickel (3-2) Cobalt ion concentration; 2 to 21 g / l (Cobalt ion source-cobalt sulfate heptahydrate) (3-3) Iron ion concentration; 3 to 28 g / l (Iron ion source-ferrous sulfate heptahydrate) (3-4) zinc ion concentration: 3 to 29 g / l (zinc ion source-zinc sulfate heptahydrate) (3-5) nickel ion, cobalt ion , Total concentration of iron ions and zinc ions; 2 to 30 g / l (4) chloride ion concentration; 1 to 100 mg / l (chloride ion source-hydrochloric acid, sodium chloride) When the chloride ion concentration is less than 1 mg / l When provided with the roughened layer made of copper if a metal layer, the etching factor becomes large surface roughness (Ef) tends to decrease. If it exceeds 100 mg / l, the effect of chlorine ions becomes excessive, the surface roughness of the roughened layer made of copper becomes small, the anchor effect on the resin base material becomes small, and the adhesive strength tends to decrease. The preferred range of the chloride ion concentration is 2 to
85 mg / l.

The preferred electrolysis conditions for forming the composite metal layer are as follows:
What is necessary is just to be less than the limiting current density of the plating bath (A), and it is preferable to select generally from the following ranges. Current density: 1 to 10 A / dm ² , electrolytic treatment time: 1 to 3
0 seconds, bath temperature: 10 to 60 ° C. If the current density is less than 1 A / dm ² , for example, the surface roughness of a roughened layer made of copper roughened using a sulfuric acid acidic copper plating bath also increases, Etching factor (E
f) tends to decrease, making it difficult to produce fine wiring.
If it exceeds 10 A / dm ² , the surface roughness of the roughened layer made of copper tends to be small, the anchor effect tends to decrease, and the adhesive strength tends to decrease.

The pH of the plating bath (A) is preferably selected from the range of 1.5 to 5.0. When the pH is lower than 1.5, the amount of one or more metals selected from tungsten and molybdenum in the composite metal layer and nickel,
Coating amount of at least one or more metals selected from cobalt, iron and zinc is not in a suitable range, and even if copper-like copper is formed by plating, copper-like copper is not formed up to the concave portion of copper raw foil, It tends to be formed concentrated on the part. When the pH is higher than 5.0, the dissolution time of one or more metal ions selected from the group consisting of tungsten ions and molybdenum ions becomes extremely slow, and the productivity tends to deteriorate. A more preferred pH is in the range from 2.0 to 4.0.

Due to the formation of the composite metal layer, fine particles are generated on the surface to be bonded of the copper foil, but sufficient adhesion strength cannot be obtained as it is or only by coating the layer with copper by kogashi plating or kabuse plating. Tend. Therefore, a rough layer made of copper is formed by forming a uniform bump-shaped copper on the entire layer by using a combination of kogashi plating and fogging plating to improve the adhesive strength.

That is, the copper foil obtained under the above conditions is washed with water, and the plating current (B) containing copper ions is applied to the obtained composite metal layer at a current density higher than the limiting current density of the bath. A dendritic copper electrodeposited layer is formed by kogashi plating for electrolytic treatment, and a roughened layer made of copper is formed by forming knotted copper by electrolytic plating at a current density lower than the limit current density of the bath.

The amount of copper deposited on the roughened layer made of copper is 30,0.
It is preferably from 00 to 300,000 μg / dm ² . If it is less than 30,000 μg / dm ² , the copper bump is small and sufficient adhesive strength tends not to be obtained. 30
If it exceeds 000 μg / dm ² , the adhesive strength can be obtained, but the production cost is undesirably increased. A more preferable adhesion amount is 100,000 to 200,000 μg / dm.
² The formation of the roughened layer made of copper can also be performed by repeating the steps of kogashi plating and kabuse plating a plurality of times.

The formation of the roughened layer made of copper is preferably selected from the following ranges of bath composition and electrolysis conditions when a general sulfuric acid-acidic copper sulfate bath is used. is not. Copper ion source-copper sulfate pentahydrate: 20 to 300 g / l (preferable copper ion concentration: 5 to 76 g / l) Sulfuric acid: 10 to 200 g / l Current density: kogashi plating (more than critical current density);
200 A / dm ² , kabushi plating (less than the limit current density); 1 to 20 A / dm ² electrolytic treatment time: kogashi plating; 1 to 10 seconds, kabuse plating; 40 to 100 seconds bath temperature: 20 to 60 ° C. If necessary, the copper foil on which the oxide layer is formed may be provided with a protective layer such as a chromate layer, a zinc layer, a copper-zinc alloy layer, a zinc alloy layer, a nickel-molybdenum-cobalt layer, and an indium-zinc layer provided on a normal copper foil. It is preferable to provide a rust treatment layer, a silane coupling agent treatment layer, and an adhesive resin layer such as a phenol resin, an epoxy resin, and a polyimide resin. The copper foil provided with these layers is heat-pressed and laminated as a copper foil for fine wiring with a resin substrate and used as a copper-clad laminate for a printed wiring board.

[0026]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 (1) Electrodeposited copper foil of 12 μm thickness (roughness side surface roughness Rz
1.5 μm, measured according to JIS B0601)
The substrate was pickled with a 0% by weight sulfuric acid solution for 60 seconds.

(2) The copper foil was washed with water, and copper sulfate pentahydrate 50 g / l and sodium molybdate dihydrate 2 g /
a plating bath consisting of 50 g / l of nickel sulfate hexahydrate and 20 mg / l of chloride ions (using hydrochloric acid, the same applies hereinafter), using a plating bath adjusted to pH 2.5 and a bath temperature of 30 ° C. Current density 3A on the rough side of the foil (the surface to be bonded)
/ Dm ² for 8 seconds and copper on the adhered surface side of copper foil,
A composite metal layer containing molybdenum and nickel was formed.
When the amount of each metal in the composite metal layer was determined by an ICP (inductively coupled plasma emission) analyzer, the amount of adhered copper was 7,90.
0 μg / dm ² , molybdenum adhesion amount is 110 μg / d
m ² and the attached amount of nickel were 15 μg / dm ² . The surface roughness of the treated surface after the treatment was Rz 1.5 μm.

(3) Next, the copper foil was washed with water, and 130 g / l of copper sulfate pentahydrate and 100 g of sulfuric acid were placed on the composite metal layer.
/ L, electrolytic treatment at a current density of 30 A / dm ² for 3 seconds (limit current density or higher) using a plating bath adjusted to a bath temperature of 30 ° C., and electrolytic treatment at a current density of 5 A / dm ² for 80 seconds (limit current density ) To form a roughened layer made of copper. The amount of copper deposited on the roughened layer made of copper is 150,000.
μg / dm ² , and the surface roughness was Rz 2.2 μm. In the obtained roughened electrolytic copper foil, formation of a uniform bumpy copper was observed over the entire copper raw foil.

(4) Next, the copper foil was washed with water and subjected to a current density of 0.7 A / A in an aqueous solution adjusted to 3.5 g / l of sodium dichromate dihydrate, pH 4.2, and a bath temperature of 30 ° C. dm
Electrolysis treatment was performed for 2.7 seconds at ² to form a rustproof layer.

(5) Further, the copper foil was washed with water, immersed in an aqueous solution containing 0.1% by weight of 3-glycidoxypropyltrimethoxysilane for 10 seconds, and immediately dried at 80 ° C. to form a silane coupling agent-treated layer. Formed.

(6) Subsequently, FR-5 equivalent glass
A pressure of 3.8 MPa, a press temperature of 168 ° C., and a press time of 90 apply to the surface to be bonded between the epoxy resin-impregnated base material and the copper foil.
The adhesive strength between the substrate and the copper foil was measured at room temperature (copper foil width 1 mm) in accordance with JIS C 6481. The results are shown in Table 1.

(7) Using the copper-clad laminate of (6) above,
Fine wiring having a circuit width of 50 μm and a space between circuits of 50 μm was produced by etching. The top width and the bottom width of the fine wiring were measured with a metallographic microscope, and E was calculated based on the above equation.
The value of f was calculated. The results are shown in Table 1.

Example 2 After the same pickling and water washing as in Example 1 was performed using the same electrolytic copper foil as in Example 1, copper sulfate pentahydrate 50 g / l and sodium molybdate dihydrate were used. 2 g / l, cobalt sulfate 7
A plating bath consisting of 30 g / l of hydrate, 30 g / l of ferrous sulfate heptahydrate and 40 mg / l of chloride ions was treated at pH 2.
0, using a plating bath adjusted to a bath temperature of 30 ° C., the rough surface side (adhered surface) of the copper foil is subjected to electrolytic treatment at a current density of 3 A / dm ² for 8 seconds, and copper is applied to the adhered surface side of the copper foil. , A composite metal layer containing molybdenum, cobalt and iron. When the amount of each metal in the composite metal layer was determined by an ICP (inductively coupled plasma emission) analyzer, the amount of copper deposited was 7,900 μg / dm.
² , the amount of molybdenum is 60 μg / dm ² , the amount of cobalt is 12 μg / dm ² , and the amount of iron is 11 μg / d
m ² . The surface roughness of the treated surface after the treatment is Rz 1.5
μm. Next, a roughened layer made of copper was formed in the same manner as in Example 1. The amount of copper deposited on the roughened layer was 150,000
0 μg / dm ² , and the surface roughness was Rz 2.3 μm.
In the obtained roughened electrolytic copper foil, formation of a uniform bumpy copper was observed over the entire copper raw foil.

After performing the treatments (4) and (5) of Example 1, the adhesive strength was measured in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculated. The results are shown in Table 1.

Example 3 The same acid as in Example 1 was prepared using the same electrolytic copper foil as in Example 1.
After washing and water washing, copper sulfate pentahydrate 50 g / l,
Sodium butyrate dihydrate 2g / l, zinc sulfate heptahydrate
Consisting of 50g / l of material and 5mg / l of chloride ion
The plating bath was adjusted to pH 2.5 and bath temperature 30 ° C.
The copper foil has a current density of 4 A on the rough surface side (adhered surface).
/ Dm^TwoElectrolytic treatment for 6 seconds, copper on the adhered surface side of the copper foil,
A composite metal layer containing molybdenum and zinc was formed. composite
The amount of each metal in the metal layer is determined by ICP (inductively coupled plasma emission).
The amount of copper deposited was 7,900 μg /
dm^TwoAnd the amount of molybdenum attached is 130 μg / dm.^Two,zinc
20 μg / dm ^TwoMet. Treated surface after treatment
Had a surface roughness Rz of 1.5 μm. Next, with Example 1
Similarly, a roughened layer made of copper was formed. This roughened layer of copper
Adhered amount is 150,000 μg / dm^Two, Surface roughness is Rz
It was 2.5 μm. The obtained roughened electrolytic copper foil
The formation of a uniform bump-like copper was observed over the entire copper raw foil.

After performing the treatments (4) and (5) of Example 1, the adhesive strength was measured in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculated. The results are shown in Table 1.

Example 4 After the same pickling and water washing as in Example 1 was performed using the same electrolytic copper foil as in Example 1, copper sulfate pentahydrate 50 g / l and sodium tungstate dihydrate were used. A plating bath composed of 2 g / l, nickel sulfate hexahydrate 50 g / l, and chloride ion 85 mg / l was adjusted to a pH of 3.0 and a bath temperature of 30 ° C. by using a plating bath adjusted to a rough surface side of the copper foil ( The surface to be bonded was subjected to electrolytic treatment at a current density of 4 A / dm ² for 6 seconds to form a composite metal layer containing copper, tungsten and nickel on the surface to be bonded of the copper foil. When the amount of each metal in the composite metal layer was quantified using an ICP (inductively coupled plasma emission) analyzer, the amount of copper deposited was 7,900 μg / dm ² and the amount of tungsten deposited was 20.
μg / dm ^2, the adhesion amount of nickel was 14 [mu] g / dm ^2. The surface roughness of the treated surface after the treatment was Rz 1.5 μm. Next, a roughened layer made of copper was formed in the same manner as in Example 1. The amount of copper deposited on the roughened layer was 150,000 μg /
dm ² , and surface roughness Rz2.1 μm. In the obtained roughened electrolytic copper foil, formation of a uniform bumpy copper was observed over the entire copper raw foil.

After the treatments (4) and (5) of Example 1 were further performed, the adhesive strength was measured as in (6) of Example 1, and the Ef value was measured as in (7) of Example 1. Calculated. The results are shown in Table 1.

Example 5 Using the same electrolytic copper foil as in Example 1, washing with acid and water as in Example 1, copper sulfate pentahydrate 50 g / l, sodium tungstate dihydrate 10 g / l, cobalt sulfate heptahydrate 30 g / l, ferrous sulfate heptahydrate 30 g / l
Bath containing 2 mg / l of chlorine ion and pH
Using a plating bath adjusted to 2.0 and a bath temperature of 30 ° C., the rough side (the surface to be bonded) of the copper foil is subjected to electrolytic treatment at a current density of 2 A / dm ² for 8 seconds, and the surface to be bonded of the copper foil. Then, a composite metal layer containing copper, tungsten, cobalt and iron was formed. When the amount of each metal in the composite metal layer was determined by an ICP (inductively coupled plasma emission) analyzer, the amount of copper deposited was 3,900 μg.
/ Dm ² , the adhesion amount of tungsten is 80 μg / dm ² , the adhesion amount of cobalt is 10 μg / dm ² , and the adhesion amount of iron is 13
μg / dm ² . The surface roughness of the treated surface after the treatment is R
z was 1.5 μm. Next, a roughened layer made of copper was formed in the same manner as in Example 1. The surface roughness was Rz 3.0 μm. In the obtained roughened electrolytic copper foil, formation of a uniform bumpy copper was observed over the entire copper raw foil.

After performing the treatments (4) and (5) of Example 1, the adhesive strength was measured in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculated. The results are shown in Table 1.

Example 6 After the same pickling and water washing as in Example 1 was performed using the same electrolytic copper foil as in Example 1, copper sulfate pentahydrate 50 g / l and sodium tungstate dihydrate were used. 1 g / l, sodium molybdate dihydrate 2 g / l, zinc sulfate heptahydrate 50 g
/ L and a plating bath consisting of 10 mg / l of chloride ions,
Using a plating bath adjusted to pH 2.5 and a bath temperature of 30 ° C., a current density of 3 A / d was applied to the rough surface side (adhered surface) of the copper foil.
An electrolytic treatment was performed for 8 seconds at m ² to form a composite metal layer containing copper, tungsten, molybdenum, and zinc on the surface to be bonded of the copper foil. The amount of each metal in the composite metal layer was quantified by an ICP (inductively coupled plasma emission) analyzer.
900 μg / dm ² , tungsten adhesion 40 μg
/ Dm ^2, the adhesion amount of molybdenum 100μg / dm ^2, the adhesion amount of the zinc was 28μg / dm ^2. The surface roughness of the treated surface after the treatment was Rz 1.5 μm. Next, Example 1
A roughened layer made of copper was formed in the same manner as described above. Surface roughness is Rz
2.3 μm. In the obtained roughened electrolytic copper foil, formation of a uniform bumpy copper was observed over the entire copper raw foil.

After the treatments (4) and (5) of Example 1 were further performed, the adhesive strength was measured in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculated. The results are shown in Table 1.

Example 7 A rolled copper foil having a thickness of 18 μm (surface roughness Rz 1.0 μm) was pickled and washed with water in the same manner as in Example 1, and a current density of 4 A / By performing an electrolytic treatment at dm ² for 6 seconds, a composite metal layer containing copper, tungsten and nickel was formed on the surface to be bonded of the copper foil. Adhesion amount of copper in the composite metal layer 7,900μg / dm ^2, the adhesion amount of tungsten 20μg / dm ^2, the adhesion amount of nickel 14 [mu] g / dm ²
Met. The surface roughness of the treated surface after the treatment is Rz 1.0 μm
Met. Next, a roughened layer made of copper was formed in the same manner as in Example 1. The surface roughness was Rz 1.5 μm.

After performing the treatments (4) and (5) of Example 1, the adhesive strength was measured in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculated. The results are shown in Table 1.

Comparative Example 1 A copper foil obtained by performing the same treatment as in Example 1 except that the plating bath for forming the composite metal layer (2) in Example 1 did not contain chlorine ions. It was Rz 2.3 micrometers when the rough surface side surface roughness was measured. Using the obtained copper foil, the measurement of the adhesive strength was performed in the same manner as in (6) of Example 1, and the Ef value was calculated in the same manner as in (7) of Example 1. The results are shown in Table 1.

Comparative Example 2 A copper foil obtained by performing the same treatment as in Example 4 except that the plating solution forming the composite metal layer had a chloride ion concentration of 150 mg / l. When the roughness on the rough surface side was measured, it was Rz 2.0 μm. Using the obtained copper foil, the measurement of the adhesive strength was performed in the same manner as in (6) of Example 1, and the Ef value was calculated in the same manner as in (7) of Example 1. The results are shown in Table 1.

COMPARATIVE EXAMPLE 3 After the treatments (1) and (2) of Example 1 were performed using the same copper foil as in Example 1, the copper foil was washed with water and copper sulfate 5
Hydrate 130 g / l, sulfuric acid 100 g / l, bath temperature 30 ° C
Using a plating bath adjusted to a current density of 30 A / dm ²
For 3 seconds to form a dendritic copper layer (kogashi plating layer). The amount of copper deposited on the dendritic copper layer was 18,000 μg / dm ² , and the surface roughness of the copper foil on the rough side was Rz 2.2 μm.

After the treatments (4) and (5) of Example 1 were performed, the adhesive strength was measured in the same manner as in Example 1 (6). Table 1 shows the results. Further, when a fine circuit was manufactured in the same manner as in (7) of Example 1, a large amount of residual copper was observed between the circuits, and it was impossible to calculate the Ef value.

Comparative Example 4 After the treatments (1) and (2) of Example 1 were carried out using the same copper foil as in Example 1, the copper foil was washed with water and copper sulfate 5
Hydrate 130 g / l, sulfuric acid 100 g / l, bath temperature 30 ° C
An electrolytic treatment (less than the limit current density) was performed at a current density of 5 A / dm ² for 80 seconds using the plating bath adjusted to form a smooth copper layer (Kabse plating layer). The amount of copper adhering to the smooth copper layer was 132,000 μg / dm ² , and the surface roughness of the copper foil on the rough side was Rz 2.0 μm.

After the treatments (4) and (5) of Example 1 were further performed, the measurement of the adhesive strength was performed in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculations were made.
The results are shown in Table 1.

COMPARATIVE EXAMPLE 5 Using the same electrolytic copper foil as in Example 1, the same acid washing and water washing as in Example 1 was performed, and copper sulfate pentahydrate 130 g / l without forming a composite metal layer. Using a plating bath of 100 g / l sulfuric acid and a bath temperature of 30 ° C., the copper foil was subjected to electrolytic treatment (above the limit current density) at a current density of 30 A / dm ² for 3 seconds on the rough side (the surface to be bonded) of the copper foil. An electrolytic treatment (less than the limit current density) was performed at a density of 5 A / dm ² for 80 seconds to form a roughened layer made of copper. The amount of copper deposited on the roughened layer made of copper is 15
0.00 μg / dm ² , the surface roughness of the copper foil on the rough side is Rz
It was 4.5 μm.

After performing the treatments (4) and (5) in Example 1, the adhesive strength was measured in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculations were made.
The results are shown in Table 1.

Comparative Example 6 After the same pickling and water washing as in Example 1 was performed using the same rolled copper foil as in Example 7, 130 g / l of copper sulfate pentahydrate was formed without forming a composite metal layer. Using a plating bath adjusted to 100 g / l sulfuric acid and a bath temperature of 30 ° C., the copper foil to be bonded was subjected to an electrolytic treatment at a current density of 30 A / dm ² for 3 seconds (above the limit current density) at a current density of 5 A. / Dm ² for 80 seconds (less than the limit current density) to form a roughened layer made of copper. The amount of copper deposited on the roughened layer made of copper is 15
0.00 μg / dm ² , the surface roughness of the copper foil on the rough side is Rz
It was 4.0 μm.

After performing the treatments (4) and (5) of Example 1, the measurement of the adhesive strength was performed in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculations were made.
The results are shown in Table 1.

COMPARATIVE EXAMPLE 7 Using the same electrolytic copper foil as in Example 1, the same pickling and water washing as in Example 1 was carried out, and copper sulfate pentahydrate 100 g / l without forming a composite metal layer. 120 g / l sulfuric acid, 0.6 g / l sodium tungstate dihydrate and 15 g / l ferrous sulfate heptahydrate using a plating bath having a bath temperature of 35 ° C. Current density 40A on the surface to be bonded)
/ Dm ² for 3.5 seconds (more than critical current density)
Then, copper sulfate pentahydrate 250 g / l, sulfuric acid 100
g / l, a plating temperature of 50 ° C. and a current density of 5
An electrolytic treatment (less than the limit current density) was performed at A / dm ² for 80 seconds to form a roughened copper layer containing tungsten and iron. The surface roughness of the copper foil on the rough side was Rz 3.8 μm.

After the treatments (4) and (5) of Example 1 were further performed, the measurement of the adhesive strength was performed in the same manner as in (6) of Example 1, and the Ef value was measured in the same manner as in (7) of Example 1. Calculations were made.
The results are shown in Table 1.

[0058]

[Table 1]

The copper foil for fine wiring obtained in Examples 1 to 7 has a small surface roughness Rz of 3.0 μm or less on the roughened surface side and maintains an adhesive strength of 1.0 kN / m or more. . In addition, the Ef value was higher than that of the comparative example having the same level of adhesive strength, and the formed fine wiring pattern had a good shape. In the examples, no copper particles remained on the substrate side, but in Comparative Examples 3, 5, and 6, copper particles remained.

The copper-clad laminate formed by lamination using the copper foil for fine wiring of the present invention is suitable for producing a printed wiring board having high-density wiring.

[0061]

According to the method of the present invention, a copper foil for fine wiring with good etching characteristics can be produced while maintaining the practical bonding strength with the resin substrate. Accordingly, a fine wiring circuit can be provided by forming various copper-clad laminates using the copper foil obtained by the method of the present invention and forming a printed circuit.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a circuit copper foil for explaining an etching factor.

[Explanation of symbols]

 A Cross section of circuit copper foil B Electrically insulating base material WT Top width of circuit copper foil WB Bottom width of circuit copper foil H Thickness of circuit copper foil

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Yagihashi 1226 Shimoedashiri, Shimodate City, Ibaraki Pref.

Claims (2)

[Claims] Claims 1. A copper foil is used as a cathode, and on a surface to be bonded of the copper foil,
(1) copper ion, (2) metal ion of at least one metal selected from tungsten and molybdenum, (3) metal ion of at least one metal selected from nickel, cobalt, iron and zinc, and (4) Chloride ion 1-10
By performing electrolysis using a plating bath (A) containing 0 mg / l at a current density lower than the limiting current density of the bath,
(I) providing a composite metal layer comprising at least one or more metals selected from copper, (II) tungsten and molybdenum and (III) at least one or more metals selected from nickel, cobalt, iron and zinc; Using a plating bath (B) containing copper ions on the composite metal layer, electrolytic treatment at a current density higher than the limit current density of the bath,
Forming a dendritic copper electrodeposition layer, and further performing an electrolytic treatment at a current density less than the limit current density of the bath to form a bumpy copper, thereby providing a roughened layer made of copper; Method of manufacturing foil. 2. A plating bath (A) containing 5 to 25 g of copper ions.
/ L, a total of 0.006 to 11 g / l of tungsten ion and molybdenum ion, and a total of 2 to 30 g / l of nickel ion, cobalt ion, iron ion and zinc ion.
l, containing 1 to 100 mg / l of chloride ions, having a pH of 1.5 to 5.0, and a plating bath (B) containing 5
The method of claim 1 containing from about -76 g / l.