JP6090693B2 - Surface-treated copper foil and printed wiring board using the surface-treated copper foil - Google Patents

Description

  The present invention provides a surface-treated copper foil having a peeling strength and a long-term antirust property without forming a layer containing a chromium component on the surface of the copper foil, and a printed wiring using the surface-treated copper foil. Regarding the board.

The copper foil used for the printed wiring board is required to have a peeling strength that does not easily peel off from the resin base material in a normal environment (normal state). , Maintain the peel strength without deterioration even when immersed in various chemicals used in the manufacturing process of printed wiring boards, and do not generate powder or etching residue. Rust prevention is also required.
In order to satisfy the above requirements, a layer containing a chromium component is usually formed on the surface of a copper foil for a printed wiring board, and in many cases a chromate film is formed.

  The chromium component of the chromate film has been confirmed to be trivalent chromium which is not toxic and has a low environmental impact, as measured by X-ray photoelectron spectroscopy or diphenylcarbazide absorptiometry. However, the chromate film treatment solution contains hexavalent chromium, and if the disposal method of the surface-treated copper foil with the chromate film formed is wrong or due to external environmental factors at the time of disposal, Trivalent chromium may be oxidized to hexavalent chromium.

  Hexavalent chromium is a highly toxic substance with a high environmental impact. In Europe, in accordance with the ELV Directive (End-of Life Vehicles Directive) for reducing the environmental impact of used vehicles, automotive parts and their The use of hexavalent chromium is prohibited in principle, as is the case with lead, mercury and cadmium, and the RoHS Directive (Restriction of the use of certain Hazardous Substances in electrical) and electronic equipment) are also prohibited from using hexavalent chromium, and printed wiring boards using surface-treated copper foil containing a chromium component are also the object.

  As the awareness of environmental load increases, even non-toxic chromium components may change to toxic hexavalent chromium, so they do not contain any chromium components and are used for printed wiring boards. The development of a surface-treated copper foil having such characteristics has been desired.

  In Patent Document 1, a nickel or nickel alloy layer and a nickel oxide layer are formed by hot air drying on the surface of the copper foil, and a copper foil for a printed wiring board in which a silane coupling layer is formed on the surface of the nickel oxide layer is roughened. A copper foil for a printed wiring board provided with a plating layer is disclosed.

  Patent Document 2 discloses that a roughened copper foil has a nickel or nickel alloy layer as a barrier layer, a zinc or zinc alloy layer as a heat-resistant layer, a molybdenum compound film as a rust-proofing layer, and a silane coupling. The copper foil for printed wiring boards which formed the agent layer in order is disclosed.

JP 2009-117706 A JP-A-2005-353918

  Patent document 1 and patent document 2 are trying to ensure the peeling strength which replaces a chromate film | membrane, performing the roughening process on the surface and raising surface roughness and obtaining the adhesive strength by a throwing effect.

  It is well known that if the surface roughness is increased by the roughening treatment, the anchoring effect will result in a stronger adhesion to the resin base material and an increase in the peel strength, so that a peel strength can be obtained instead of the chromate film. It is better to increase the surface roughness.

  However, recent printed wiring boards have a problem in that circuits are extremely narrowed with downsizing of electronic devices, and when the surface roughness is increased, narrow pitch circuits cannot be formed accurately.

  Further, when the surface roughness increases, there are problems that the etching factor is reduced and etching residues and powder fall off on the substrate.

  Therefore, it is preferable not to increase the surface roughness in order to accurately form a narrow-pitch circuit without generating a residue or the like on the substrate, and the number of cases where the roughening treatment is not performed is increasing. However, when the roughening treatment is not performed, a sufficient anchoring effect cannot be obtained, and the adhesive strength is lowered, resulting in a problem that the peeling strength is also lowered.

The present inventors made it a technical subject to solve the above-mentioned problems, and as a result of many trial and error trial manufactures and experiments, a roughened layer and 0.3 μm or less were formed on one surface of the copper foil. A fine particle layer composed of copper particles, copper-nickel particles, copper-cobalt particles or copper-nickel-cobalt particles, a layer composed of nickel or nickel-phosphorus, and a layer composed of an alkali metal silicate and a silane coupling agent. If formed in this order, not only the normal peel strength, but also the peel strength is maintained even after being immersed in various chemicals used in high temperature environment, moisture absorption, or printed circuit board manufacturing process. rust resistance can be obtained over a long term, and narrow circuit pitch can be accurately formed, in addition, the area per 60 [mu] m ² of 177 .mu.m ² a surface area increased by forming fine particle layer ~900μm ^The above technical problem has been achieved by obtaining a remarkable knowledge that a surface-treated copper foil that does not fall off is obtained in the range of ² .

  The technical problem can be solved by the present invention.

The present invention provides a roughening layer on one surface of a copper foil and a fine particle layer comprising one kind of fine particles selected from copper particles, copper-nickel particles, copper-cobalt particles, and copper-nickel-cobalt particles. A layer made of nickel or nickel-phosphorus and a layer made of an alkali metal silicate and a silane coupling agent are formed in this order, and the particle diameter of the fine particles is 0.3 μm or less (excluding 0 μm). the surface treated copper foil related (claim 1 the surface area of the fine particle layer, characterized in that the are area per 60μm ² ~900μm ² increase of 177 .mu.m ² than the surface area of the fine particle layer formed prior to the roughening treatment layer ).

The present invention is also characterized in that the alkali metal silicate is water glass represented by M ₂ O · xSiO ₂ · nH ₂ O (M = Na or K, x = 2 to 4). The surface-treated copper foil according to claim 1 (claim 2).

  In the present invention, the silane coupling agent is at least one selected from an amino group-containing silane coupling agent, an epoxy group-containing silane coupling agent, and a vinyl group-containing silane coupling agent. It is related with the surface-treated copper foil of 1 or 2.

Moreover, this invention relates to the printed wiring board which uses the surface-treated copper foil in any one of Claims 1 thru | or 3 on the resin base material (Claim 4).

  According to the present invention, even if a layer containing a chromium component is not formed, a normal peeling strength can be obtained without impairing the etching property, and even after a high temperature environment or after moisture absorption, In addition to being able to maintain the peel strength even when immersed in various chemicals used in the manufacturing process, it does not fall off and has long-term rust prevention properties, so the characteristics required for copper foil used for printed wiring boards It becomes the surface treatment copper foil provided with.

  Since the particle diameter of the fine particles constituting the fine particle layer formed on the surface-treated copper foil of the present invention is 0.3 μm or less (however, 0 μm is not included), the increase in surface roughness is suppressed and the surface area is increased. Therefore, it can be firmly fixed to the resin base material, and sufficient peel strength can be obtained without forming a layer containing a chromium component.

  In addition, since the increase in surface roughness is small, the frequency of occurrence of etching residue and powder fall is reduced, and a narrow-pitch circuit can be accurately formed. It becomes the surface treatment copper foil which can be used suitably.

In addition, an increase in surface area due to the formation of the fine particle layer, 1 77 m ² of So areas per 60μm ² ~900μm ^2, peel strength can be secured although dusting or etching residue on a printed wiring board that do not occur It becomes the surface-treated copper foil which has a preferable property when using it.

  Since the nickel or nickel-phosphorus layer is formed on the surface-treated copper foil in the present invention, the peel strength even in a high temperature environment or even when immersed in various chemicals used in the printed wiring board manufacturing process Can be maintained.

  In addition, the nickel-phosphorus layer is highly versatile because it is soluble in an alkaline etching solution having selective etching properties.

  Since the surface-treated copper foil in the present invention is formed with a layer comprising an alkali metal silicate and a silane coupling agent, the surface-treated copper foil is firmly fixed to the resin base material to improve the normal peel strength, and also absorbs moisture. Even after, deterioration is suppressed, the peel strength is maintained, and rust prevention is improved.

In particular, water glass represented by M ₂ O.xSiO ₂ .nH ₂ O (M = Na or K, x = 2 to 4) and an amino group-containing, epoxy group-containing or vinyl group-containing silane coupling agent If used, deterioration after moisture absorption is further suppressed, and rust prevention is further improved.

It is a schematic diagram of the cross section of the surface treatment copper foil in this invention.

(Copper foil)
The copper foil before each treatment (hereinafter referred to as untreated copper foil) used in the present invention is not particularly limited, and any copper foil having no distinction between the front and back and a copper foil having a distinction between the front and back can be used. .

  One surface to be surface-treated (hereinafter referred to as the treated surface) is not particularly limited, and the rolled copper foil may be any surface, and any electrolytic copper foil may be either a precipitation surface or a glossy surface. The surface is good.

  Although the thickness of untreated copper foil will not be specifically limited if it is the thickness which can be used for a printed wiring board after surface treatment, 6 micrometers-300 micrometers are preferable, More preferably, they are 9 micrometers-150 micrometers.

In the present invention, it is preferable to subject the treated surface of the untreated copper foil to a roughening treatment in advance. This is because a fine particle layer can be easily formed and an improvement in the normal peeling strength can be expected.
However, when an increase in surface roughness due to the roughening treatment is not preferable, a fine particle layer can be directly formed on the treated surface of the untreated copper foil. This is because the fine particle layer in the present invention does not increase the surface roughness, but increases the surface area, so that the fine particle layer adheres to the resin substrate and provides a peel strength.

  An example of the case where the roughening treatment is performed is a method in which coating plating is performed after the dendritic powder of copper or copper alloy is attached to the treated surface.

  In the roughening treatment, in order to prevent the step of attaching the dendritic powder of copper or copper alloy with a current equal to or higher than the limit current density (step 1) and the dropping of the attached dendritic powder, the coating is performed with a current less than the limit current density. (Step 2).

For example, in Step 1, a mixed solution of copper sulfate pentahydrate 12 g / L to 70 g / L and sulfuric acid 30 g / L to 200 g / L is added to chlorine ions, cobalt ions, nickel ions, iron ions, titanium ions, molybdenum ions, Add one or more selected from vanadium ion, zinc ion, tungsten ion, aluminum ion, 1-10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 3-mercapto-1-propanesulfonic acid Then, after adjusting the liquid temperature to 25 ° C. to 50 ° C., an insoluble electrode such as a white metal oxide-coated titanium plate is used as the electrode, and the dendritic copper powder is used at a current density of 5 A / dm ^{2 to} 100 A / dm ^2. Can be attached.

For example, in Step 2, after adjusting a mixed liquid of copper sulfate pentahydrate 150 g / L to 300 g / L and sulfuric acid 50 g / L to 200 g / L to a liquid temperature of 25 ° C. to 50 ° C., a white metal oxide is applied to the electrode. an insoluble electrode such as coated titanium plate may be coated plated at a current density of 2A / dm ² ~60A / dm ² using. If necessary, an appropriate amount of gelatin, which is a known technique, may be added.

(Fine particle layer)
The particles forming the fine particle layer are copper particles having a particle size of 0.3 μm or less, copper-nickel particles, copper-cobalt particles or copper-nickel-cobalt particles, and more preferably the fine particles having a particle size of 0.25 μm or less. is there.

  If the particle size is larger than 0.3 μm, the surface roughness is remarkably increased, the etching property is deteriorated and the sticking property is also weakened, powder falling occurs and the production line is contaminated, or an etching residue is generated on the substrate surface. Since there is a possibility, it is not preferable.

Preferably the surface area increases by forming a fine particle layer on the treated surface of the untreated copper foil is an area per 60μm ² ~900μm ² of 177 .mu.m ^2, more preferably 70μm ² ~800μm ^2, more preferably 100 [mu] m ² ˜700 μm ² .
Can not be is less than 60 [mu] m ² to obtain a sufficient peel strength, also not preferable because the deterioration rate after moisture absorption is large, if the amount exceeds 900 .mu.m ^2, although the peel strength is obtained, Since the surface roughness increases and powder falling occurs, the production line may be contaminated, and etching residue may be generated on the substrate surface, which is not preferable as a surface-treated copper foil used for a printed wiring board.

  The surface area can be measured by, for example, a laser microscope using a violet laser having a visible light limit wavelength of 408 nm.

  The fine particle layer in the present invention can be formed by electroplating.

The fine particle layer of the present invention is, for example, a copper-containing compound 10 g / L to 100 g / L or a copper-containing compound 10 g / L to 100 g / L and a cobalt-containing compound 1 g / L to 60 g / L and / or a nickel-containing compound. A liquid mixture containing 1 g / L to 60 g / L and a diethylenetriamine salt added so as to be 5 g / L to 300 g / L has a pH of 2.5 to 13.0 and a liquid temperature of 20 ° C. to 70 ° C. And using copper as the anode, the current density is 0.5 A / dm ^{2 to} 10.0 A / dm ² and the amount of electricity is 10 A · sec / dm ^{2 to} 400 A · sec / dm ^2. it can.

  The copper-containing compound is preferably copper sulfate pentahydrate, the cobalt-containing compound is cobalt sulfate heptahydrate, cobalt chloride, and the nickel-containing compound is nickel sulfate hexahydrate or nickel chloride.

  Diethylenetriaminepentaacetic acid pentasodium is preferred as the diethylenetriamine salt.

(Nickel or nickel-phosphorus layer)
Nickel or nickel in the present invention - the adhesion amount of the phosphorus layer is preferably ^{5mg / m 2 ~300mg / m 2} , more preferably from ^{10mg / m 2 ~200mg / m 2} . If it is less than 5 mg / m ² , the copper foil surface on which the fine particle layer is formed cannot be completely coated, and the resin base material reacts with copper to form a brittle layer, which is pulled after high temperature environment or chemical immersion. This is not preferable because the deterioration rate of the peel strength may increase. Further, if the amount exceeds the amount of adhered 300 mg / m ^2, generation of etching residue is not preferable because there is a risk that the rate of etching is slow, also be greater than 300 mg / m ² increase in heat and chemical characteristics It is because it cannot be expected.

  The nickel or nickel-phosphorus layer in the present invention can be formed by electroplating.

The nickel or nickel-phosphorus layer in the present invention contains, for example, a nickel-containing compound of 10 g / L to 100 g / L or a nickel-containing compound of 10 g / L to 100 g / L and a phosphate of 0.1 g / L to 10 g / L. The liquid mixture in which sodium acetate trihydrate was added to the liquid so as to be 2 g / L to 20 g / L was adjusted so that the pH was 3.0 to 5.5 and the liquid temperature was 20 ° C. to 50 ° C., It can be formed using platinum as the anode under the conditions of a current density of 0.1 A / dm ^{2 to} 10.0 A / dm ² and an electric quantity of 1.0 A · sec / dm ^{2 to} 30.0 A · sec / dm ² .

  As the nickel-containing compound, nickel sulfate hexahydrate, nickel chloride, and as the phosphate, sodium hypophosphite monohydrate and sodium phosphite are suitable.

(Alkali metal silicate and silane coupling agent layer)
The alkali metal silicate in the present invention is not particularly limited, but water glass represented by M ₂ O · xSiO ₂ · nH ₂ O (M = Na or K, x = 2 to 4) is preferable. Used. As the water glass, either a sodium salt or a potassium salt can be used, but a potassium salt is more preferable.

  The silane coupling agent in the present invention is not particularly limited, and a silane coupling agent containing a vinyl group, an epoxy group, a styryl group, a methacryl group, an acrylic group, an amino group, a ureido group, and a mercapto group should be used. However, amino group, epoxy group or vinyl group-containing silane coupling agents are more suitable because they have very high effects of moisture absorption resistance and rust prevention.

  A silane coupling agent may be used alone or in combination of two or more.

In the present invention, the alkali metal silicate and silane coupling agent layer is prepared by dissolving an alkali metal silicate and a silane coupling agent and immersing them in a mixed aqueous solution adjusted to 20 ° C. to 60 ° C. or spraying. It can form by spraying by the method etc., and washing with water.

  The concentration of the alkali metal silicate in the mixed aqueous solution is preferably 0.5 mL / L to 100 mL / L, more preferably 1 mL / L to 80 mL / L. If it is less than 0.5 mL / L, the deterioration rate of the peel strength after the moisture absorption treatment is increased, which is not preferable. Even if it is added in excess of 100 mL / L, no further decrease in the deterioration rate after moisture absorption can be expected. It is.

  The concentration of the silane coupling agent in the mixed aqueous solution is preferably 0.3 mL / L to 100 mL / L, more preferably 0.5 mL / L to 80 mL / L. If it is less than 0.3 mL / L, the deterioration rate after moisture absorption and the effect of rust prevention are not sufficient, and even if added over 100 mL / L, no further improvement in effect can be expected. .

  Examples of the present invention are shown below, but the present invention is not limited thereto.

(Roughening treatment)
After immersing a rolled copper foil having a surface roughness of RzJIS 1.1 μm and a thickness of 18 μm in a mixed liquid adjusted to 45 g / L of copper sulfate pentahydrate, 100 g / L of sulfuric acid, 20 ppm of chloride ions, and a liquid temperature of 30 ° C., platinum As an anode, dendritic copper powder was adhered to the surface of the rolled copper foil under the conditions of a current density of 10 A / dm ² and an electrolysis time of 12 seconds.

In order to prevent the adhering dendritic copper powder from falling off, it was immersed in a mixed solution adjusted to 250 g / L of copper sulfate pentahydrate, 100 g / L of sulfuric acid, and a liquid temperature of 30 ° C., and then current density of 5 A / dm using platinum as an anode. ^2. Electrolysis was performed in an electrolysis time of 70 seconds, and the attached dendritic copper powder was completely covered with copper plating to obtain a rolled copper foil subjected to roughening treatment.

  All the examples and comparative examples of the present invention used rolled copper foil subjected to roughening treatment.

(Fine particle layer)
Roughened rolled copper foil was washed with water for 10 seconds, copper sulfate pentahydrate, nickel sulfate hexahydrate, cobalt sulfate heptahydrate, diethylenetriaminepentaacetic acid pentasodium (trade name: Clewat DP80 (content rate 35 to 45%) ・ Nagase ChemteX Co., Ltd.) is mixed at the ratio shown in Table 1, and copper is used as the anode, and electroplating is performed under the same conditions of pH, liquid temperature, current density and electrolysis time as shown in Table 1. And the fine particle layer of the surface treatment copper foil of Examples 1-12 and Comparative Examples 1-5 was formed.

(Nickel or nickel-phosphorus layer)
The rolled copper foil on which the fine particle layer was formed was washed with water for 10 seconds, and then nickel sulfate hexahydrate, sodium hypophosphite monohydrate, and sodium acetate trihydrate were mixed at the ratio shown in Table 2 to obtain platinum. Was used as an anode, and electroplating was carried out under the conditions of pH, liquid temperature, current density and electrolysis time shown in Table 2 to form nickel or nickel-phosphorous layers of Examples 1-12. Further, Comparative Examples 1 to 5 were formed under the same conditions as in Example 1.

(Alkali metal silicate and silane coupling agent layer)
After the rolled copper foil on which the fine particle layer and the nickel or nickel-phosphorous layer are formed is washed with water for 10 seconds, potassium silicate (2K potassium silicate: manufactured by Nippon Chemical Industry Co., Ltd.), sodium silicate, lithium silicate, N -2 (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and vinyltrimethoxysilane were mixed as shown in Table 3, and Table 3 After dipping at the described liquid temperature and dipping time, it was washed with water for 10 seconds and then naturally dried to form alkali metal silicate and silane coupling agent layers in Examples 1-12. Comparative Examples 1 to 5 were formed under the same conditions as in Example 1.

(Comparative Example 6)
It was created under the same conditions as in Example 1 except that the fine particle layer was not formed.

(Comparative Example 7)
It was created under the same conditions as in Example 1 except that no nickel or nickel-phosphorus layer was formed.

(Comparative Example 8)
It was created under the same conditions as in Example 1 except that the alkali metal silicate and silane coupling agent layers were not formed.

(Comparative Example 9)
Using a rolled copper foil that has been roughened, a mixed solution of nickel sulfate hexahydrate 176 g / L and citric acid monohydrate 20 g / L is adjusted to a liquid temperature of 40 ° C., and platinum is used for the anode. Then, a nickel plating layer was formed under the conditions of a current density of 2.0 A / dm ² and an electrolysis time of 4 seconds.

  Then, after forming a nickel oxide layer on the nickel plating surface by performing hot air drying in the atmosphere at 200 ° C., it is immersed in a 5 mL / L 3-aminopropyltrimethoxysilane aqueous solution for 10 seconds and washed in the air without being washed with water. And was dried at 200 ° C. for 1 minute.

(Comparative Example 10)
Using a roughed rolled copper foil, a mixed solution of nickel sulfate hexahydrate 300 g / L, nickel chloride 45 g / L, boric acid 50 g / L was adjusted to a liquid temperature of 50 ° C., and platinum was used as the anode. Was used to form a nickel plating layer under the conditions of a current density of 2 A / dm ² and an electrolysis time of 4 seconds.

The rolled copper foil on which the nickel plating layer is formed is washed with water for 10 seconds, and then a mixed solution of zinc sulfate 300 g / L and sodium sulfate 70 g / L is adjusted to a liquid temperature of 40 ° C. A galvanized layer was formed under the conditions of 2 A / dm ² and electrolysis time of 4 seconds.

After washing with water for 10 seconds, the mixture of sodium molybdate dihydrate 25 g / L and sodium citrate dihydrate 30 g / L was adjusted to a liquid temperature of 25 ° C. and pH 5 and platinum was used as the anode to obtain a current density. A molybdate film was formed under the conditions of 0.2 A / dm ² and cathodic electrolysis time of 30 seconds.

  Thereafter, it was washed with water for 10 seconds, immersed in a 10% 3-aminopropyltrimethoxysilane solution at room temperature for 10 seconds, and immediately dried at 80 ° C. to prepare.

(Comparative Example 11)
Using a rolled copper foil that has been roughened, a mixture of nickel sulfate hexahydrate 30 g / L, sodium hypophosphite monohydrate 0.2 g / L, and sodium acetate trihydrate 10 g / L The solution was adjusted to a liquid temperature of 30 ° C. and a pH of 4.5, and platinum was used for the anode to form a nickel-phosphorous plating layer under the conditions of a current density of 2.0 A / dm ^{2 and an} electrolysis time of 2 seconds.

After washing with water for 10 seconds, a mixed solution of sodium dichromate 10 g / L and sodium hydroxide 40 g / L is adjusted to a liquid temperature of 30 ° C., platinum is used for the anode, current density is 2.0 A / dm ² , electrolysis A chromate layer was formed under conditions of 5 seconds, then washed with water for 10 seconds and air dried.

  The measuring method of the Example of this invention and a comparative example is described.

(10-point average roughness RzJIS)
A stylus type surface roughness meter defined in JISB0651-2001 was used.
A stylus having a tip radius of 2 μm was used, and a 10-point average roughness RzJIS defined in JISB0601-1994 was measured with a cut-off value for a roughness curve of 0.8 mm and a measurement distance of 4.0 mm.

(Surface area measurement)
Using a color 3D laser microscope and a violet laser with a visible light limit wavelength of 408 nm (VK-9710 manufactured by Keyence Corporation), an area with a surface area of 177 μm ² was measured under the objective lens 150 times, high definition, and optical 6 times zoom conditions.

The surface roughness after the roughening treatment measured by the measurement method was RzJIS2.9 μm.
Therefore, the surface roughness increased by the roughening treatment is RzJIS1.8 μm.

Further, the surface area was the region per 865Myuemu ² of 177 .mu.m ^2.
The value of “increased surface area” described in Table 4 is a value obtained by subtracting 865 μm ² which is the surface area after the roughening treatment from the surface area after the formation of the fine particle layer.

(Particle size)
Using a scanning electron microscope, the size of particles forming a fine particle layer was measured at a magnification of 10,000.

(Normal peel strength)
Three FR-4 substrates were stacked, and heated and pressure-molded by a press machine at a pressure of 40 kgf / cm ² , a temperature of 170 ° C., and a time of 60 minutes to obtain a copper-clad laminate. An etching machine was used to produce a 1 mm wide copper circuit sample by etching. In accordance with JIS C 6481, the peel strength was measured using a universal testing machine.

(Heat treatment)
A copper circuit sample having a width of 1 mm was subjected to a heat treatment at a temperature of 180 ° C. for 48 hours using an atmospheric oven, and the peel strength was measured.

(Hygroscopic treatment)
A 1 mm wide copper circuit sample was boiled in ion exchange water for 120 minutes. Subsequently, it was washed with water and dried, and then the peel strength was measured.

(Hydrochloric acid aqueous solution treatment)
A 1 mm wide copper circuit sample was immersed in an 18 wt% aqueous hydrochloric acid solution having a liquid temperature of 25 ± 2 ° C. for 60 minutes, washed with water, dried, and then peeled off.

(Deterioration rate)
The deterioration rate (%) after each treatment was calculated by the following equation.

(Powder falling test)
Place a test paper (filter paper Grade 2) 30 mm wide and 100 mm long on the surface-treated copper foil of the present invention, apply a load (200 g / φ30 mm) on one side, drag the filter paper 120 mm horizontally, and adhere to the filter paper The obtained copper powder was visually observed, and when there was no powder adhesion, it was judged as “good”, and when powder was adhered, it was judged as “poor”.

(Rust prevention)
After leaving for 3 days under conditions of a temperature of 60 ° C. and a humidity of 85 ° C. using a thermo-hygrostat, the surface-treated surface was visually judged.
Evaluation was performed according to the following criteria.

Rust prevention evaluation criteria
○: Discoloration and black spots are not recognized
×: Discoloration or black spot is recognized
XX: Both discoloration and black spots are recognized.

  Table 4 shows the results of the normal peel strengths of Examples 1 to 12 and Comparative Examples 1 to 11, the peel strength after various treatments, the deterioration rate of each peel strength, the powder falling off, and the rust prevention properties.

  Compared with the surface roughness increased by the aforementioned roughening treatment, the increase in surface roughness due to the formation of the fine particle layer of Examples 1 to 12 of the present invention is very low, however, the surface area is greatly increased. Can be confirmed (Table 4).

  Moreover, Examples 1-12 of this invention have the value of normal state peeling strength higher than the comparative example 11 in which the chromate layer is formed. In addition, it can be confirmed that this is a well-balanced surface-treated copper foil that has all the characteristics required for a printed wiring board excellent in rust prevention property that does not cause discoloration and black spots (Table 4).

  In addition, from Comparative Examples 6 to 8, if any one of the fine particle layer, the nickel or nickel phosphorus layer, the alkali metal silicate layer, and the silane coupling layer in the present invention is lacking, the normal peel strength decreases. , The rate of deterioration of the peel strength after each treatment is increased, and if any of the nickel or nickel phosphorus layer, alkali metal silicate and silane coupling layer is lacking, rust prevention cannot be maintained. It can be confirmed that the surface-treated copper foil having the characteristics of the present invention is not obtained even if lacking (Table 4).

Since the present invention does not include a layer containing a chromium component, the environmental load is low, a normal peel strength can be obtained in place of the surface-treated copper foil having a chromate film formed, and even in a high temperature environment or after moisture absorption, or In addition to being able to maintain the peel strength even after being immersed in chemicals, it does not fall off, has a long-term rust-proof property, and balance that satisfies the characteristics required for copper foil for printed wiring boards The surface-treated copper foil is highly industrially applicable because it can be manufactured without introducing special equipment or equipment.

1 Copper foil 2 Fine particle layer 3 Nickel or nickel-phosphorus layer 4 Alkali metal silicate and silane coupling agent layer
5 roughening treatment layer

Claims (4)

A roughened layer on one surface of the copper foil, a fine particle layer made of one kind of fine particles selected from the following group A, a layer made of nickel or nickel-phosphorus, an alkali metal silicate and a silane coupling agent Are formed in this order, and the particle diameter of the fine particles is 0.3 μm or less (however, 0 μm is not included), and the surface area of the fine particle layer is the roughened layer before the formation of the fine particle layer. surface treated copper foil, characterized in that the are area per 60μm ² ~900μm ² increase of 177 .mu.m ² than the surface area.
Group A: copper particles, copper-nickel particles, copper-cobalt particles, copper-nickel-cobalt particles Surface treatment according to claim 1, wherein the alkali metal silicate is characterized in that it is a water glass which is represented by _{M 2 O · xSiO 2 · nH} 2 O (M = Na or K, x = 2~4) Copper foil. The surface-treated copper foil according to claim 1 or 2, wherein the silane coupling agent is at least one selected from the following group B.
Group B: amino group-containing silane coupling agent, epoxy group-containing silane coupling agent, vinyl group-containing silane coupling agent The printed wiring board which uses the surface-treated copper foil in any one of Claims 1 thru | or 3 on a resin base material.

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