JP2002012998A - Copper foil for printed wiring board and surface treatment method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper foil for a printed wiring board particularly superior in soft etching property as well as resistance to heat discoloration, rust prevention capability, and solderability, and to provide a surface treatment method therefor. SOLUTION: The copper foil for the printed wiring board comprises a first layer consisting of 12-50 mg/m2 zinc layer containing 0.1-2.5 wt.% sulfur adhering on at least one side of a surface of the copper foil, and a second layer consisting of a chromate layer on the first layer, which is formed by means of adhering 0.5-2.5 mg/m2 chromium and 1.5-6 mg/m2 besides phosphor as required. The surface treatment method for the copper foil for the printed wiring board is characterized by forming the second layer consisting of the chromium by dipping the first layer into a solution containing a chromium compound, or a chromium compound and a phosphorus compound, and electrolyzing it as a cathode, after forming the first layer consisting of the zinc alloy layer containing the sulfur by dipping at least one side of the surface of the copper foil in a solution containing a zinc compound and a sulfur compound, and electrolyzing it as a cathode.

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 a printed wiring board, and more particularly, to a conductive material such as a printed wiring board, which has a uniform roughened surface and a reduced resin content. The present invention relates to a copper foil for a printed wiring board which has been subjected to a surface treatment having high adhesiveness, and a surface treatment method thereof.

[0002]

2. Description of the Related Art Printed wiring boards are used in large quantities for electronic and electrical materials, and are becoming more sophisticated and reliable, and their required characteristics are becoming more complex and diverse. . Strict quality is also required for copper foil, which is one of the constituent materials of this printed wiring board.

In order to manufacture a printed wiring board, first, the rough side of a copper foil is laminated with an insulating synthetic resin-impregnated base material, laminated by heating and pressing with a press to form a copper-clad laminate, and then a wiring circuit is formed. It is completed after forming processing. At this time, in the case of a glass-epoxy resin base material (FR-4) which is generally used as a synthetic resin-impregnated base material, the temperature is about 1 to about 170 ° C.
Press for 2 hours to complete the copper clad laminate. In the case of high heat-resistant resin such as glass / polyimid resin base material, 220 ℃
In some cases, a high temperature such as pressing at a temperature of 2 hours is required.

As a copper foil for printed wiring boards, one side has a rough surface,
Electrolytic copper foil having a glossy surface on one side is overwhelmingly used. In general, an electrolytic copper foil is obtained by electrolytically depositing copper from a copper electrolytic solution, producing an original foil called an untreated copper foil, and then performing the following surface treatment.

That is, the surface of a copper foil for a printed wiring board that adheres to a resin substrate usually has a side (non-glossy surface side) that adheres to the substrate, In rolled copper foil, either one of the surfaces is subjected to pickling and then subjected to a surface roughening treatment, and further, a treatment to ensure heat discoloration resistance and chemical resistance, and a treatment to improve and stabilize etching characteristics and the like. Is being done. On the other hand, the surface on the side not bonded to the resin base material is required to have different properties from the bonded surface side, that is, heat discoloration resistance, solder wettability, and the like. For this reason, the copper foil for printed wiring boards requires a different treatment method for each of the adhesive surface side and the non-adhesive surface side, and various technologies have been developed and proposed, and have a highly functional surface.

Further, after press, post-curing at a high temperature for a long time is sometimes performed to improve the dimensional accuracy. For example, heat discoloration resistance is required year by year. Further, even in a flexible printed circuit board using a material other than the glass / epoxy resin base material, a heat treatment at a high temperature for a long time may be performed. Therefore, among the characteristics required on the non-adhesive surface side of the copper foil, heat-resistant discoloration is one of extremely important characteristics.

Further, the multilayer printed wiring board is made of glass
After making a primary laminated board with a wiring circuit formed on copper foil on a base material such as epoxy resin, it is manufactured by laminating another resin substrate on the circuit of this primary laminated board to make a multilayer printed wiring board. ing. As a pretreatment for laminating another resin substrate on the primary laminated board on which the wiring circuit is formed, the wiring circuit is subjected to a blackening process for the purpose of improving adhesion. Usually, before the blackening layer is formed, the wiring circuit may be subjected to soft etching in order to improve the adhesion between the wiring circuit and the blackening layer. Alternatively, an etching resist is used to form a wiring circuit, but soft etching may be performed on the copper foil before the circuit is formed in order to improve the adhesion with the resist. Thus, the soft etching process is indispensable in the manufacture of printed wiring boards,
It is required that the treated surface has a large roughness and a uniform rough surface. Usually, sodium persulfate-sulfuric acid, ammonium persulfate-sulfuric acid, and hydrogen peroxide-sulfuric acid are used as soft etching agents.

Various techniques for imparting heat-resistant discoloration have been conventionally proposed. For example, Japanese Patent Publication No. Sho 54-29187 discloses a method of forming a film by immersing copper in an alkaline aqueous solution containing zinc or energizing copper in the aqueous solution as a cathode. Discloses a method of providing a coating layer of a mixture of zinc or zinc oxide and chromium oxide. Japanese Patent No. 2517503 discloses a method of forming a Zn—Ni alloy layer and then performing a chromate treatment. Further, Japanese Patent Application Laid-Open No. 5-299834 proposes a copper foil provided with a composite layer containing zinc, chromium and phosphorus.

[0009]

However, in the above-mentioned conventional method, in any case, unevenness due to soft etching is large, so that a uniformly roughened copper foil surface cannot be obtained. It was not able to sufficiently exert the force and did not sufficiently suggest improvement of the soft etching property. Furthermore, the coating layer of a mixture comprising zinc or zinc oxide and chromium oxide disclosed in Japanese Patent Publication No. 58-7077 has good solder wettability, but the thickness of the coating layer is thin, so that heat discoloration resistance, The rust prevention was low.
Further, the copper foil surface obtained by a method of performing a chromate treatment after forming a Zn-Ni alloy layer disclosed in Japanese Patent No. 2517503 has a problem in solder wettability.

[0010] The present invention has been proposed in view of the above-mentioned conventional circumstances, and particularly, is a copper for a printed wiring board having excellent soft etching properties and excellent heat discoloration resistance, rust prevention, solder wettability, and the like. An object of the present invention is to provide a foil and a surface treatment method thereof.

[0011]

In order to achieve the above object, the present invention employs the following constitution. That is, a sulfur-containing zinc alloy layer containing 0.1 to 2.5% by weight of sulfur is deposited on at least one surface of the copper foil in an amount of 12 to 50 mg / m ² to form a first layer. Next, a second layer made of a chromate layer is formed on the first layer. According to this configuration, it is possible to provide a copper foil for a printed wiring board which is particularly excellent in soft etching property and excellent in heat discoloration resistance, rust prevention, solder wettability and the like. That is, the sulfur-containing zinc alloy layer greatly contributes to the soft etching property, and the presence of sulfur promotes the roughening effect of the soft etching solution on the copper foil surface, improves the soft etching property, and further improves the sulfur-containing zinc. Since a rust-preventive force and heat discoloration resistance are inferior with a film having only an alloy layer, a chromate layer is formed to improve the rust-preventive force and heat discoloration resistance.

The second layer comprises chromium 0.5 to 2.5 mg / m ² ,
It is a chromate layer to which 1.5 to 6 mg / m ² of phosphorus is adhered. According to this configuration, since the chromate layer contains phosphorus and has a predetermined amount of coating, rust prevention and heat discoloration resistance are further improved.

First, the first layer of the copper foil for a printed wiring board of the present invention will be described. The first layer is obtained by depositing a zinc layer containing sulfur on the glossy surface of the copper foil. The adhesion amount of the first layer is 12 to 50 mg / m ² , and it is necessary that the first layer adheres almost uniformly to the glossy surface of the copper foil. However, the effect of the present invention is not affected even if the thickness is not uniform and there is a slight variation in thickness. When the amount is 50 mg / m ² or more, the effect is not increased and uneconomical.In addition, since zinc has low electric conductivity, the electric conductivity is lowered, which is not preferable. It is not preferable because the copper foil deviates from the standard of purity. If it is less than 12 mg / m ² , the heat discoloration resistance is poor, which is not preferable.

The amount of sulfur attached is preferably 0.1 to 2.5% by weight with respect to zinc. If it is less than 0.1% by weight, the soft etching property is reduced. If it is more than 2.5% by weight, the soft etching property is not affected. It is not preferable because the rust resistance decreases.

Although there are various methods for forming the first layer, a method using cathodic electrolysis (electroplating) is the easiest, industrially, inexpensive, and optimal method. In the cathodic electrolysis, electrolysis is performed using a copper foil as a cathode in an aqueous solution (electrolytic bath) containing a zinc compound and a sulfur compound.

As the zinc compound, zinc sulfate, zinc acetate, zinc citrate, zinc oxide and the like can be used. As sulfur compounds, thiourea, allylthiourea,
Thiourea compounds and sulfur-containing organic compounds such as acetylthiourea, aminobenzothiazole, thioacetamide, imidazolidinethione, benzimidazolethiol, mercaptothiazoline, cystine, thiodiethanol, thiodipropionic acid, and triazinethiol, and sodium thiosulfate, sulfurized Inorganic compounds such as potassium can be used.

The electrolytic bath and the electrolytic conditions are not particularly limited. For example, the following are preferred. _{ZnSO 4 · 7H 2 O 0.03 ~} 0.50 mol / l (8.6 ~ 144 g / l) CH 3 COONa · 3H 2 O 5 ~ 50 g / l of sulfur-containing compounds 1 ~ 1000 ppm pH 3.0 ~ 5.0 bath temperature 20 ~ 40 ° C. Current density 0.1-3.0 A / dm ² Electric quantity 0.5-2.0 Coulomb / dm ^{2 The} pH is adjusted using sulfuric acid or sodium hydroxide.

Next, the second layer of the copper foil for printed wiring boards of the present invention will be described. The second layer is formed on the first layer of the present invention. This is a chromate layer, and if it has a substantially uniform layer shape, the effect of the present invention is not affected even if the thickness slightly changes. The adhesion amount of chromium is preferably 0.5 to 2.5 mg / m ² . In addition, it is more preferable that phosphorus is contained in the chromate layer because the heat discoloration resistance and the rust-preventing power can be further improved, and the amount of the phosphorus compound attached is 1.5 to 6 mg / m ² as phosphorus. . If the amounts of chromium and phosphorus are less than the above ranges, the rust resistance and heat discoloration resistance will be low.

The method of forming the second layer includes a method of performing electrolysis using a copper foil as a cathode in an aqueous solution containing a chromium compound or a chromium compound and a phosphorus compound (cathodic electrolysis).
Easiest, cheapest and optimal. In this case, the current density is preferably 0.1 to 3 A / dm ² , and the electrolytic treatment time is preferably 1 to 10 seconds.

As the chromium compound, hexavalent chromium compounds such as sodium dichromate, potassium dichromate and chromium trioxide can be used. An aqueous solution having a chromium concentration of 0.2 to 10 g / l is appropriate. Phosphorus compounds include trisodium phosphate, disodium hydrogen phosphate,
Uses sodium dihydrogen phosphate, tripotassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, lithium phosphate, sodium pyrophosphate, potassium pyrophosphate, sodium tripolyphosphate, phosphoric acid, sodium hypophosphite, etc. it can. 1 to 20 g / l as phosphorus in the working solution
Is suitable.

The pH of the treatment bath for forming the second layer is suitably from 4 to 12, and if the pH is lower or higher than the above range, the disadvantage that both the zinc in the first layer is dissolved occurs. Not so good.

The above-described processing is for the processing on the glossy surface side, but the processing for the rough surface side will be briefly described below. First, the surface roughening for improving the adhesive strength with the applied resin substrate is performed, for example, by a method as described in Japanese Patent Publication No. 50-40109. Alternatively, after copper dendritic deposition is performed on the copper foil, copper plating is performed to fix the copper foil to form a rough copper particle surface. Next, by forming a barrier layer such as Japanese Patent Publication No. 2-24037, and further adding a rust prevention layer,
Be completed.

Further, copper particles are precipitated on the glossy side of the copper foil and subjected to a roughening treatment, and a barrier treatment, a chromate treatment and a rust prevention treatment are performed by a known method, and the first layer of the present invention is applied to the roughened surface. , A second layer may be formed. On the copper foil for a printed wiring board of the present invention, benzotriazole, tolyltriazole, imidazole, benzimidazole, azoles such as azoles, silane coupling agent and the like to further improve rust prevention and the like. Is also good.

The first layer according to the present invention greatly contributes to the soft etching property, and the presence of sulfur promotes the roughening effect of the soft etching solution on the copper foil surface, thereby improving the soft etching property. As the second layer, a film containing only a sulfur-containing zinc layer is inferior in rust resistance and heat discoloration resistance. Therefore, a chromate layer made of chromium or chromium and phosphorus is formed to improve rust resistance and heat discoloration resistance. It is a thing.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below.

Example (1) The roughened surface of the electrolytic copper foil having a thickness of 35 μm was roughened by a known method, and the glossy surface of the electrolytic copper foil was subjected to (A) bath ZnSO ₄ .7H ₂ O 25 g. / l CH ₃ COONa ・ 3H ₂ O 10 g / l imidazolidine thione 1 g / l pH 4.0 In a bath at a temperature of 30 ° C, perform a cathodic electrolysis with a current density of 0.4 A / dm ² and an energization time of 3 seconds. In the bath, the cathode was electrolyzed at 0.6 A / dm ² for 3 seconds, washed with water, and dried. The heat discoloration resistance, solder wettability, and rust resistance of the glossy surface of this copper foil were examined, and the results are shown in Table 1. The copper foil was laminated on a FR-4 grade glass / epoxy resin-impregnated base material, pressed at 3.9 MPa, at 170 ° C. for 60 minutes, and molded. The soft etching property of the glossy surface of this copper clad laminate was examined, and the results are shown in Table 1. In addition,
Methods for measuring properties such as soft etching property, heat discoloration property, solder wettability, and rust resistance will be described later.

Example (2) After roughening the roughened side of a 35 μm thick electrolytic copper foil by a known method, the glossy surface of the electrolytic copper foil was treated with the bath (A) of Example (1). The same processing as in Example (1) was performed except that the cathodic electrolysis was performed at a current density of 0.7 A / dm ² and a conduction time of 3 seconds. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Example (3) After roughening the roughened side of a 35 μm thick electrolytic copper foil by a known method, the glossy surface of the electrolytic copper foil was treated with the bath (A) of Example (1). The same processing as in Example (1) was performed except that the cathodic electrolysis was performed at a current density of 0.4 A / dm ² and a conduction time of 2 seconds. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Example (4) The rough side of a 35 μm thick electrolytic copper foil was roughened by a known method, and the glossy surface of the electrolytic copper foil was After performing cathodic electrolysis with a current density of 0.4 A / dm ² and a conduction time of 3 seconds in the bath of No. 1, and washing with water, the cathodic electrolysis was performed at 0.6 A / dm ² for 3 seconds in the bath (B) of Example (1). , Washed with water and dried. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Example (5) The rough side of a 35 μm thick electrolytic copper foil was roughened by a known method, and the glossy surface of the electrolytic copper foil was In the bath of the above, after cathodic electrolysis at a current density of 0.4 A / dm ² and a conduction time of 3 seconds, and after washing with water, In the bath, the cathode was electrolyzed at 0.6 A / dm ² for 3 seconds, washed with water, and dried. Example 1 shows the characteristics of the glossy surface of this copper foil.
And the results are shown in Table 1.

Example (6) After the roughened side of the electrolytic copper foil having a thickness of 35 μm was roughened by a known method, the glossy surface of the electrolytic copper foil was subjected to the sodium thiosulfate concentration of Example (5). The same processing as in all the examples (5) was performed except that the amount was changed to 1 g / l. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Example (7) The rough side of the electrolytic copper foil having a thickness of 35 μm was roughened by a known method, and the glossy surface of the electrolytic copper foil was subjected to (F) bath ZnO 7 g / l NaOH 50 g. / l benzimidazole thiol 0.1 g / l In a bath at a temperature of 30 ° C, cathodic electrolysis is performed at a current density of 0.4 A / dm ² and a conduction time of 3 seconds, and after washing with water, the same as (E) in Example (5). In the bath
Cathodic electrolysis was performed at 0.6 A / dm ² for 3 seconds, washed with water, and dried. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Example (8) The rough side of a 35 μm thick electrolytic copper foil was roughened by a known method, and the glossy surface of the electrolytic copper foil was After performing cathodic electrolysis with a current density of 0.4 A / dm ² and a conduction time of 4 seconds in the bath of No. 1 and washing with water, the same bath as the bath (E) of Example (5) was used.
Cathodic electrolysis was performed at 0.6 A / dm ² for 3 seconds, washed with water, and dried.
The properties of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Example (9) The rough side of a 35 μm thick electrolytic copper foil was roughened by a known method, and the glossy surface of the electrolytic copper foil was After performing cathodic electrolysis with a current density of 0.4 A / dm ² and a conduction time of 4 seconds in the bath of No. 1 and washing with water, the same bath as the bath (E) of Example (5) was used.
Cathodic electrolysis was performed at 0.6 A / dm ² for 3 seconds, washed with water, and dried. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Example (10) The roughened side of a 35 μm thick electrolytic copper foil was roughened by a known method, and the glossy surface of the electrolytic copper foil was the same as the bath (D) of Example (5). In the bath, the cathode was electrolyzed at a current density of 0.3 A / dm ² and an energizing time of 3 seconds, and washed with water. Then, in the same bath as the bath (E) of Example (5), the cathode was 1.0 A / dm ² for 3 seconds. Electrolyzed, washed with water and dried. The characteristics of this copper foil were examined in the same manner as in Example (1),
Table 1 shows the results.

Example (11) After roughening the rough side of an electrolytic copper foil having a thickness of 35 μm by a known method, the glossy surface of the electrolytic copper foil was treated with the bath (H) of Example (9). In the same bath except that potassium sulfate was changed to 70 mg / l, cathodic electrolysis was performed at a current density of 0.5 A / dm ² for 4 seconds, and after washing with water, the bath (E) of Example (5) was used. In the same bath as above, 1.0 A / dm ^{2 was} subjected to cathodic electrolysis for 3 seconds, washed with water, and dried. Example 1 shows the characteristics of the glossy surface of this copper foil.
And the results are shown in Table 1.

[0037]

[Comparative Example] Comparative Example (1) The glossy side of an electrolytic copper foil (thickness 35μ) whose rough side has been roughened by a known method In the bath of the above, after cathodic electrolysis at a current density of 0.4 A / dm ² and a conduction time of 3 seconds, and after washing with water, In the bath, the cathode was electrolyzed at 0.6 A / dm ² for 3 seconds, washed with water, and dried. Example of the properties of the glossy surface of this copper foil
Investigation was performed in the same manner as in (1), and the results are shown in Table 1.

Comparative Example (2) The glossy surface of an electrolytic copper foil (thickness: 35 μm) whose rough side was roughened by a known method was used. In the bath No. ² , the cathode was subjected to cathodic electrolysis at a current density of 2.0 A / dm ² and a conduction time of 5 seconds, washed with water, and dried. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Comparative Example (3) The glossy surface of an electrolytic copper foil (thickness: 35 μm) whose rough side had been roughened by a known method was used. In the bath No. ¹ , the cathode was electrolyzed at 1.0 A / dm ² for 3 seconds, washed with water and dried. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1.

Comparative Example (4) The glossy surface of an electrolytic copper foil (thickness: 35 μm) having a roughened surface roughened by a known method was used. In the bath of the above, after cathodic electrolysis at a current density of 0.4 A / dm ² and a conduction time of 3 seconds, and after washing with water, In the bath, the cathode was electrolyzed at 0.2 A / dm ² for 3 seconds, washed with water and dried. The characteristics of the glossy surface of this copper foil were examined in the same manner as in Example (1), and the results are shown in Table 1. In addition, Ni was 2 mg / m ² among the attached elements.

[0041]

[Table 1]

The "soft etching property" means that the treated copper foil was immersed in an aqueous solution containing 220 g / l of sodium persulfate and 6 g / l of sulfuric acid at a liquid temperature of 40 ° C. with stirring for 30 seconds.
After washing with water, drying was performed, and the appearance of the surface was determined by observation. The criteria were as follows: ：: Roughening was sufficiently performed, and there was no gloss after the soft etching process. X: Gloss appearance was slightly retained, and roughening was not so advanced. The gloss is measured using a gloss meter (light receiving angle 6
0 degrees). As for the glossiness, the lower the value, the less gloss and the roughened surface. A good value is about 40 or less. Except for the method of the present invention, the glossiness is 50 to 60, while in the present invention it is a numerical value of 20 to 35, which is a great difference, and it can be seen that the effect of the present invention is great.

"Heat-resistant discoloration" means that the treated copper foil is placed in a hot-air circulation oven, heated at 240 ° C. for 1 hour,
The degree of discoloration of the glossy surface was visually observed. The criterion was: ：: no discoloration □: slight discoloration (○, □ has no practical problem) Δ: partial discoloration ×: complete discoloration XX: intensity discoloration.

"Solder wettability" is based on IPC-MF-150F, section 4.5.12, immersed in a 0.1 mol / l hydrochloric acid aqueous solution at 25 ° C. for 10 seconds as a pretreatment, washed with water, Dry and WWG
After applying the rosin flux, it was immersed in a solder bath at 235 ° C., and the degree of wetting was visually determined. ○ indicates a state of being completely wetted with solder, and X indicates a state of being not so wet.

The "rust prevention power" was determined by visually observing the degree of oxidative discoloration of the treated copper foil after keeping it in a thermo-hygrostat maintained at 60 ° C. and 85% relative humidity for 72 hours. The criterion was as follows: ほ と ん ど: Almost no oxidation □: Slightly oxidized (O and □ have no practical problems) Δ: Slightly oxidized ×: Oxidized over the entire surface

The copper foil obtained by the method of the present invention has good and uniform roughening in soft etching properties, and exhibits good heat discoloration even after heat treatment at 240 ° C. for 1 hour. A copper foil having no adverse effect on wettability and the like, and further having excellent rust-preventive properties and having good properties can be obtained.

[0047]

According to the present invention, there is obtained a copper foil for a printed wiring board having extremely high surface properties, which is particularly excellent in soft etching property, heat resistance discoloration property, rust prevention property, solder wettability and the like. Can be It is considered that this greatly contributes to improvement in reliability of the printed wiring board. Moreover, this surface treatment method can be easily applied to manufacturing equipment,
Mass production is possible.

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[Procedure amendment]

[Submission Date] May 14, 2001 (2001.5.1)
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

Various techniques for imparting heat-resistant discoloration have been conventionally proposed. For example, Japanese Patent Publication No. 54-29187 discloses a method of forming a coating by immersing copper in an alkaline aqueous solution containing zinc or energizing copper as an anode in the aqueous solution. Discloses a method of providing a coating layer of a mixture of zinc or zinc oxide and chromium oxide. Japanese Patent No. 2517503 discloses a method of forming a Zn—Ni alloy layer and then performing a chromate treatment. Further, Japanese Patent Application Laid-Open No. 5-299834 proposes a copper foil provided with a composite layer containing zinc, chromium and phosphorus.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4K024 AA05 AA17 AB02 BA09 BB11 BC02 CA02 DB04 GA01 GA04 GA14 4K044 AA06 AB02 BA10 BB03 BC02 BC05 BC08 CA17 CA18 5E343 AA15 AA17 BB24 BB67 CC34 CC50 CC78 DD43 EE55 GG02GG18

Claims (3)

[Claims] 1. The method according to claim 1, wherein at least one surface of the copper foil has a thickness of 0.1%.
12 sulfur-containing zinc alloy layers containing ~ 2.5% by weight sulfur
What is claimed is: 1. A copper foil for a printed wiring board, comprising: a first layer having a thickness of about 50 mg / m ² , and a second layer of chromate formed on the first layer. 2. The method according to claim 1, wherein the second layer comprises chromium 0.5 to 2.5 mg /
m^Two, Phosphorus 1.5-6mg / m ^TwoChromate
The print arrangement according to claim 1, wherein the print arrangement is a layer.
Copper foil for wire plate. 3. A step of immersing at least one surface of the copper foil in an aqueous solution containing a zinc compound and a sulfur compound, and performing cathodic electrolysis to form a first layer made of a sulfur-containing zinc alloy; Dipping in an aqueous solution containing a compound or a chromium compound and a phosphorus compound and performing cathodic electrolysis to form a second layer made of chromate.