JPH0533193A - Metallic copper foil and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a copper foil having excellent adhesion between resin and copper foil and having an acid resistance at its interface. [Structure] It has a metallic copper surface that is matte in appearance, has a surface hue in the range of 7.5RP to 7.5Y of Munsell color chart, a lightness of 7 or less, and a saturation of 12 or less. Characteristic copper metal foil. [Effect] According to the present invention, regarding the adhesion between the copper foil and the resin,
The unevenness of the surface of the copper foil is kept low (the reference height L of the cross section defined by the surface roughness of JIS B 0601 is 100 μm.
, The peel strength is 0.3K even if Rz is 6 μm or less.
It is possible to have characteristics of g / cm ² or more and excellent resistance to hydrochloric acid.

Description

Detailed Description of the Invention [0001] FIELD OF THE INVENTION The present invention forms a composite with a resin.
Copper foil, especially for printed circuit boards.
A suitable copper foil and its manufacturing method. [0002] 2. Description of the Related Art Conventionally, regarding adhesion between metal and resin,
Seed as a metal surface treatment method to enhance the adhesion with
Various methods have been considered. For example, mechanical or acid
Etching of metal surface with oxidizer in acidic liquid
And after roughening, often with an alkaline liquid or
Even if the liquid is acidic, the pH of the metal surface is
Forming an oxide film on the metal surface by utilizing the increase
And to bond the metal and resin through the oxide film
There is a law. Specifically, for example, as an acidic liquid for copper
Etching is performed using an aqueous solution containing cupric chloride and hydrochloric acid.
After roughening the copper surface, chlorous acid, phosphoric acid, caustic
The alkaline solution containing soda oxidizes the copper on the copper surface.
A film is formed and the resin is allowed to pass through this oxide film at room temperature, or
Is heated, and is further bonded by heating and pressing. Also metal
As a method of forming an oxide film on the surface, permanganate
There is also a method of oxidation treatment with a liquid containing sodium hydroxide and sodium hydroxide.
is there. Furthermore, as a method for forming an oxide film, ultraviolet irradiation
Or, there is a flame treatment or the like. Also, iron phosphate
When immersed in iron, iron is oxidized by phosphoric acid,
The pH of the iron surface rises due to hydrogen generation, and
This produces a stable iron phosphate. Resin is the oxidation of these metals
It has a high strength of adhesion through a substance or metal salt.
Growls However, these metal oxides or salts are
It has the drawback of being weak against acid. Metal-resin compound
Coalescence is often used in an atmosphere that is in contact with acid
There are cases. Therefore, the metal-resin composite is mechanically bonded.
Not only strength but also chemical stability is desired
There is. By the way, as a method for improving the adhesion of the copper coating,
The technology disclosed in Japanese Laid-Open Patent Publications 56-35497 and 57-177593.
It In both cases, the copper coating is once oxidized and then in a high temperature reducing atmosphere
Under the pure metal surface, the copper oxide is reduced until the pure copper becomes bright.
The technique for obtaining the surface is disclosed.
Disclosed to eliminate the fragility of this grain by eliminating the child
is doing. In other words, the copper with a glossy surface without particles is
It is said that the peel strength is enhanced when the laminate is formed. However
However, any of the techniques of the references are not considered according to the study by the present inventor.
However, the adhesion is not enough. As far as the inventor knows
Once effective technology for acid-resistant treatment of metal-resin interface
Not proposed. [0004] The object of the present invention is to provide a resin
~ Excellent adhesion between copper foil, and its interface has acid resistance
Another object is to provide a copper foil and a manufacturing method thereof. [0005] The copper foil according to the present invention is
It is matte and has a Munsell hue of 7.5 RP.
The range is 7.5Y, the brightness is 7 or less, and the saturation is 1
Gold having a metallic copper surface exhibiting a number of 2 or less
It is a genus copper foil. In addition, gold can be obtained by oxidizing the surface of the metal layer.
Metal oxide film obtained by the above-mentioned process
By reducing the surface, the surface hue is Munsell color chart 7.5RP
~ 7.5 Y, lightness is 7 or less, and saturation is
Including a step of forming a reduced metal surface layer exhibiting 12 or less
It is a method for producing a metal copper foil. (Interfacial condition between metal and resin; gloss and color
This interface is matte in appearance and is dark brown or black.
It is desirable to do. This degree is suitable for direct reflectance
50% or less in the wavelength range of 600 to 700 nm, and
It is preferably 20% or less. Also based on Munsell color chart
A desirable hue is in the range of 7.5RP to 7.5Y, and more desirable
The range of 10RP to 2.5Y is preferable, and the desired brightness is 7
Or less, more preferably 6 or less, desirable saturation is 12 or less
Lower, more preferably 8 or less. Therefore, for example, even if the metal is copper, this metal
The surface does not have the so-called copper metallic luster, that is, the so-called copper color.
Yes. However, this is blackened by dirt such as trout and other substances
Not presented to tea, let alone copper oxide
It is pure metal. That is, this metal surface
Fairly fine, dense or porous or spongy
Forming a surface shape, light is scattered for this reason and
It looks dark brown to black. The present invention is this degree
Since it has a very fine and dense surface state,
If they are joined together, the resin will get into the microporous parts on this surface.
Increased adhesion. Moreover, this interface is not an oxide film but a metal film.
It has acid resistance. In addition, such surface condition
State metal cannot be obtained by reduction of metal oxide film under high temperature gas.
Yes. (Direct reflectance) Evaluation by direct reflectance of the front
Value is based on a halogen lamp as the light source and nitric acid as a white plate.
By a color analyzer using barium. This anal
The operating principle of Isa is well known, and its section is described later.
I will explain the matter, but if it is abbreviated here, white diffused light
Illuminate the sample and spectrophotometrically measure the reflected light in the vertical direction.
And the spectral reflectance of the color object (spectral radiance
) And the spectral transmittance. Reflection
If you use "glossy" as a sample, the effect of gloss is strong.
Measured value excluding specular reflection light using a light trap
(Diffuse reflectance) and specular reflection using a light diffuser
The photometric value including total light (total reflectance, direct reflectance)
There is a difference. The reflectance is the reference light intensity under the same conditions.
The ratio of the reflected light intensity of the sample to the
Mari reference The sample anti-reflection with the reflected light intensity of the white plate as 100
The ratio of the light intensity). In other words, direct reflectance is regular reflection
It is the photometric value of this reflectance including up to. (Munsell color chart) Munsell color chart (Munsell
As for Book of Color, the JIS standard is used in this application.
It As is well known, this color chart (also called color chip) is a color.
Phase (Hue, H), lightness (Value, V), and saturation (Chrom
It is organized by a, C). Normally, for example, 10RP7 / 8
And read as "10 arep, 7-8".
10RP page (also called 10RP chart. This is color
Indicates a phase. ) Is open, all the colors that belong to hue 10RP
It is contained. Next, on the horizontal axis of the 7 point on the vertical axis and on the horizontal axis
When the intersection of the 8 points of and the vertical line was found, this was given.
The color chart has 10RP7 / 8 color. That is, on the vertical axis
Is V, that is, the brightness is in increments of 1, and the horizontal axis is C, that is, the saturation is 2.
It is shown in ticks. The common color name with the word tea
In terms of the representative value of the color chart, brown is 5YR3.5 / 4, shrimp
Brown is 8.5R3 / 4.5, black is 2YR2 / 1.5, dark brown
Is 5YR3.2 / 2, brown rat is 6.5YR6 / 1, Ugu
Chair tea is 5Y4 / 3.5. By the way black is these
It is called an achromatic color instead of a brownish hue, and black is an attribute of lightness.
Has color but cannot show saturation
Can not. Black is usually indicated by N1, N1.5. Black V
The value is usually 2 or less. (Interfacial state between metal and resin; uneven shape) Below
The first concave and convex portion formed on the surface of the base metal and the first concave portion
The convex surface is thinner than the first concave / convex part along the concave / convex surface.
And a second reduction metal that covers the surface with fine irregularities
The relationship with the uneven portion of is important in terms of adhesion, and
The schematic diagram of is shown. In FIG. 1, 1 is a base metal layer, and 2 is
Electrolytic reduction metal layer, 3 is a resin layer, base metal
The unevenness of the surface of the layer 1 is the first uneven portion 4,
The unevenness on the surface of the base layer 2 is the second uneven portion 5. That is, electric
Contact with the resin layer 3 via the second uneven portion 5 of the deoxidized metal layer 2.
Since the second uneven portion 5 is a fine surface,
Has a great adhesion. The electrolytic reduction metal layer 2 is made of metal.
However, since the surface is microporous as shown in the figure, light scattering
Depending on the color, it looks like a dark hue, dark brown or black. The surface roughness of the first uneven portion 4 is JIB B
When the reference length L defined by 0601 is 100 μm
It is desirable that Rz is 6 μm or less, especially 3 μm or less.
Yes. If it is roughened, it has good adhesive properties, but
This is a point where it is difficult to form a pattern by ching. Film thickness (maximum width) of the second uneven portion 5 liter
Is 70 Å or more and less than or equal to the surface roughness of the first uneven portion 4.
Is desirable. In principle, such thick films are
It can be obtained by reducing the naturally oxidized metal surface when left standing.
Instead, the metal oxide film is thickly formed as in the embodiment of the present invention.
Obtained by electroreducing this after forming into
It This surface should have the same appearance as the hue above.
However, it is better not to be glossy. (Metal) A typical metal used in the present invention is copper.
Alternatively, it is an alloy or diffusion material mainly composed of copper. Besides, iron or
Nickel or the like can be appropriately adopted. Metal oxide may remain on the copper surface.
Yes. In this case, the adhesion of copper oxide can be expected.
It However, if the amount of this metal oxide is large, problems occur in acid resistance.
Be careful when adjusting it as it twists. Also irreversibly the oxide
Of course, there is no problem in remaining. (Resin) A typical resin to be combined with the present invention is polyimide.
Although it is a system, an epoxy system or other suitable system can be adopted. Epoki
Polyimide-based materials are superior in dimensional stability compared to Si-based materials
However, on the other hand, the adhesion to copper is particularly poor, and the adhesion
If copper oxide is used for improvement, the acid resistance becomes weak. Therefore
This problem can be solved by applying the copper foil of the present invention,
A typical example is a copper-polyimide combination. multilayer
In printed boards, polyimide is used as a prepreg sheet.
And use. (Use) A typical use is so-called printing.
Circuit boards and multilayer printed boards. However, it is suitable for printed boards
In addition to use, it enhances the adhesion between copper foil and resin and is acid resistant
As a bonding method having, for example, a metal surface for a coating base
It is also useful as a treatment method. That is, the pinho in the coating film
Acid, the acid solution penetrates through the pinhole,
Therefore, an oxide film is used to increase the adhesion between the metal and the coating film.
When "used," the oxide film is eluted and the coating film is easily peeled off.
This kind of acidic liquid only touches the air,
Carbon dioxide dissolves in water and produces carbonate ions.
Easily generated. However, as described above, the
Copper foil has acid resistance and enhances adhesion between resin and metal
Is also effective. For this reason, it can be used as a copper foil for the coating film base.
Minutes are useful. (Electrolytic Reduction) An example of obtaining the copper foil of the present invention and
Then, the electrolytic reduction method will be described with reference to FIG. In the figure, 6 is a sample to be electrolytically reduced.
7 is an opposite pole. This counter electrode 7 is a stainless steel in the present application.
Although a pressure plate is used, in short, an insoluble conductor is sufficient.
Therefore, other than this, platinum, copper, carbon, lead, silver, etc. can be applied.
Wear. 8 is an electrolytic solution, but it is desirable that the pH is 6 or more
Good The arrow in the figure is the direction in which electrons (e) flow. Trial
The reaction on the surface of material 6 is [0020] [Equation 1] And [0022] [Equation 2] It is CuO melts and Cu²+ Is relatively
If there are many in the surroundings, the external power supply
Depending on the amount of electrons replenished, the reaction rate of several 2 is determined
It (Oxidation of metal surface) The reaction is carried out in order from the oxidation step.
Explaining next, Cu is NaClO₂Is oxidized by
Cu²Generates + and reacts with OH-in an alkaline solution
Cu (OH)₂And some Cu²+ Is PO_Four ³- When
React to Cu₃(PO_Four)₂Also produces a precipitate like
it is considered as. That is, the estimated reaction is [0025] [Equation 3] [0026] [Equation 4] [0027] [Equation 5] [0028] [Equation 6] [0029] [Equation 7] [0030] [Equation 8] [0031] [Equation 9] Therefore, the reaction of the sum of the equations 3 and 9 as a whole
Will progress [0033] [Equation 10] It is considered that the reaction is as follows. This
As can be seen from the above, metal oxides (Cu (OH)₂↓
→ CuO + H₂O) precipitates on the copper surface (sample 6 surface). Cu (OH)₂Is a finely divided solid and has a particle size
Is extremely small (several hundred Å)
The part 5 will be formed. (Relationship between metal deposition rate and adhesion)
The metal oxide film obtained by this process becomes metal copper when electrically reduced.
And deposit. If the speed of the deposited film is slow, crystals will form.
Defects (kinks or scratches) that have low nucleation density and are easy to precipitate
(Precipitate), crystals are selectively deposited, and the crystals are the original fine uneven shape
And grow into large crystal grains, resulting in
Adhesion may be low. However, increase the deposition rate
When it is removed, the original fine unevenness is maintained and pure metal is used.
Will be deposited as a result, the adhesion with the resin will increase and the hydrochloric acid resistance will improve.
Go up. (Relationship Between Liquid Temperature, Agitation and Metal Deposition) Current
When the density is constant, metal ions (eg
For example Cu²+) Is difficult to diffuse, so the crystal grain size is fine
become. On the other hand, when the liquid temperature is high, metal ions (Cu²+) Expansion
It becomes easy to disperse and the crystal grain size becomes large. This state is illustrated
3 shows. 3 (a) shows the case where the liquid temperature is low, and (b) shows
The case where the liquid temperature is high is shown. In addition, A in FIG. 3 easily precipitates.
Places where B is difficult to deposit. In addition, further mix with liquid.
Cu depending on the strength of stirring²+ Grain size that affects the movement of +
Will vary in size. (Current density) Immediately after electrolytic reduction, the metal is first
Precipitation starts from numerous defects on the surface of the underlying metal. Current
If the density is low, the metal will be large, centered around these original defects.
Crystals will grow. This is similar to the one in Figure 3 (b)
ing. On the other hand, if the current density is high, other than defects, that is, the base
Fine metal crystal grains on the flat surface (also called terrace) of
Is deposited and corresponds to a new defect, so the crystal growth is small.
At most, the number of crystal growth points increases. This situation is shown in Figure 3.
Similar to (a). In other words, high current density reduction is finer
Since it is easy to obtain a metal surface having irregularities, the present invention does not
Is particularly preferable. (Difference from hydrogen reduction) Unlike electrolytic reduction,
Hydrogen reduction requires high temperature (650-800 ° C) conditions
Therefore, even if there is an uneven surface, it will collapse due to heat and smoothness will appear
End up. Therefore, this method gives a metallic luster
It Due to the metal interface, acid resistance can be expected for the time being.
There is little fear of peeling due to the elution of the chemical film, but the adhesiveness is quick.
Problem remains. In electrolytic reduction, each particle of metal oxide is
It is reduced on the spot, and if the temperature rises, the crystal grows.
It Also, even if the temperature is low, most of it will diffuse and precipitate.
It The shape is apparently maintained, but strictly speaking
Has grown, and the nuclei are mainly formed on it and precipitate on it, crystal growth
To do. Therefore, a considerably fine metal film can be obtained. On the other hand, in the hydrogen reduction, oxygen is released by heat treatment.
Then, theoretically, it becomes porous, but this porous state is maintained.
It is necessary to However, if the temperature exceeds 500 ° C,
In the area, crystal growth progresses and collapse occurs as before.
It is expected that the porous state will be lost and smoothing will proceed.
Be done. (Formation Method of Base Metal) As an example,
The method of forming the copper foil is to electrolyze metal on a stainless steel plate.
And then deposit two such plates.
Precipitated metal sandwiched between surfaces to heat and pressurize metal
The layer is glued to the prepreg and is easily made from stainless steel
Remove Of course, the deposited metal on this stainless steel plate is the base metal.
As a result, oxidation and electrolytic reduction are sequentially performed, and then the prep
It may be attached to the leg. (Others, Summary) Conventionally, high metal and resin
When trying to bond strongly, the surface of the metal should be roughened and
On the surface by oxidizing the surface of the metal roughened to
An oxide film is formed on the surface, and metal and resin are separated through the oxide film.
The method of bonding has been widely used. But according to this method
Therefore, when you make a metal-resin composite,
As a result, extremely high strength can be obtained, but oxidation of the adhesive interface
Since it uses a membrane, it is easily dissolved in acid and chemically unstable.
It has the drawback of Therefore, the present inventor
Stable against acid and highly dense against resin without using
The treated film for imparting adhesiveness was examined. Resin and gold
About the adhesion mechanism of the oxide film for high strength adhesion to the genus
As a result, it was found that the surface shape of the oxide film was complicatedly roughened.
This is the main reason for the strong adhesion between resin and metal.
As compared with metal, the oxide film is more water than resin.
It facilitates elementary bonding, and this hydrogen bonding also causes metal to pass through the oxide film.
Considered as a factor for strongly binding the resin to the resin
Be done. Then, the shape of the oxide film is approximated to that of hydrogen.
Electrical reduction of the oxide film to facilitate bonding
However, a reduction film that inevitably contains an oxide is formed on the metal.
And a method of adhering metal and resin through this film
I came up with. That is, using this method,
The amount of oxide in the reduced film depends on the acid that constitutes the conventional oxide film.
Much less than the amount of compound. Therefore, acid resistance is improved
Can be expected to do. As is clear from this
In addition, when applying the present invention to the production of printed boards,
The reduced metal is exposed at the part that contacts the through hole
Is desirable. Also, regarding adhesiveness, hydrogen bonding
It is also possible to expect a printing effect due to surface roughness and surface roughening. [0045] 【Example】 (Electrolytic reduction method) As a substrate for electrolytic reduction, double-sided copper-clad epoxy
Kisshi to glass cloth plate (copper foil thickness; 35 μm, epoxy
~ Glass cloth layer 0.2mm) on the copper foil with chemical plating solution
Copper to 35 μm and then 180 in air
Heat treatment at ℃ for 1h, and further chemical oxide film formation treatment
Was used. Oxide film formation processing conditions are described in the examples below.
Is the street. The substrate is placed in an electrolytic cell 10 as shown in FIG.
Set and electrolytically reduce the oxide film on the copper foil by the constant current method.
It was The electrolytic reduction conditions were liquid temperature, stirring, and current density.
The electrolytic cell 10 has a temperature controller 11 and Ar gas.
A wiring 9 for stirring the electrolytic solution was attached. End point of reduction reaction
Is the reduction voltage-time curve, and when the reduction wave suddenly rises
It was judged based on the voltage of. (Evaluation Method of Adhesive Properties and Hydrochloric Acid Resistance) Adhesive Characteristics
The sex depended on the measurement of peel strength. The sample is electrolytic reduction
Using a sample in which the processed substrate is laminated and adhered by prepreg
It was The prepreg consists of 4 layers of 0.05mm thickness.
It was Adhesion conditions are 170 ° C, 90 minutes, 14 kg / cm²Shi
It was Hydrochloric acid resistant sample is about 1 with a low speed cutter.
0 mm²Cut into pieces and cut the section with emery paper (# 1000).
(# 2000) Al after polishing₂O₃With abrasives
Buffed and kept in hydrochloric acid solution (17.5%) at room temperature
Immerse for a while, soak from the side, and measure the discolored distance
Followed the method. (Observation of surface shape and analysis of crystal structure)
The surface morphology of copper plating film, oxidation treatment film and electrolytic reduction film
Scanning electron microscope (SEM) shows that the crystal structure is
It was investigated by the injection electron diffraction method. Furthermore, the roughness of the reduced copper surface
The surface reflectance is measured by anticipating light scattering due to its fineness.
It was. (Measurement of surface reflectance)
Direct reflectance measurement using an analyzer with the above operating principle
did. The measuring device is 607 type color manufactured by Hitachi, Ltd.
-It is an analyzer. The optical system diagram of this device is shown in Fig. 4.
It is Ri. The light source 12 is a halogen lamp 120W.
The white light from this diffuses in the integrating sphere 13 with an inner diameter of 200 mm.
It reflects and illuminates the sample 14 and the reference white plate 15. sample
The light reflected by the white plate 14 and the white plate 15 is transmitted through the transmission sample chamber 16.
After passing, it enters the sector room equipped with the mirror 17,
Rotating mirror 18 selects and alternately injects the spectroscope
The light incident on the spectroscope that illuminates the slit 19 is diffracted.
After forming a sample image on the child, it is dispersed and exit slit
20 is illuminated, and only monochromatic light with a wavelength width of 5 nm is emitted.
Incident on the photomultiplier tube through the filter 20 and the filter 21.
It In addition, 22 is an entrance lens, 23 is a sector motor, and 24
Is a grading, 25 is a triangular mirror, 26 is a light
The diffuser 27 is a hotmal. (Adhesive Properties of Electrolytic Reduction Film) Copper oxide in oxide film
As a reaction for reducing and depositing on, copper ions were hydrated
A possible route is to "dissociate" in the after-treatment liquid and then reduce and precipitate.
Be done. In order to improve the adhesive properties of the reduction film, the surface of the oxide film
After reducing the surface shape, it is necessary to keep it as it is.
In order to do so, the copper ions that have “dissociated” are not
It is necessary to immediately deposit in situ without diffusing on the surface.
In order to control the diffusion of copper ion,
Higher flow density, lower bath water and no liquid agitation
Is desirable. In the opposite case, the current density
Lower the bath temperature, raise the bath temperature, and allow liquid stirring.
In the case of reduction under conditions, replenishment of precipitated ions to crystal nuclei
Therefore, the crystal grows large and the original oxide film
Unlike the surface shape, the reducing film tends to have smoothness. Therefore, the surface shape and adhesive strength of the electrolytic reduction film
25 ℃, no stirring, and 5
Two conditions, 0 ° C and stirring, were selected and examined. Figure the result
5 shows. The adhesive properties of the reducing film immediately after electrolytic reduction are represented by i and
ii. Lower current density without liquid stirring (curve i)
And peel strength are high, while liquid stirring is possible (curve ii)
Lower flow density and higher liquid temperature Lower peel strength
It was (Hydrochloric acid resistance of electrolytic reduction film) Copper foil of the present invention
To check the hydrochloric acid resistance (17.5% HCl) of
The relationship between the acid immersion distance and the immersion time was obtained. as a result
Is shown in FIG. The electrolytic reduction conditions are 25 ° C, without stirring, 0.025, 0.0625, 0.12
5,1.25mA / cm², 50 ℃, with stirring, 0.025
0.0625, 0.125, 1.25 mA / cm²Is.
Depending on the conditions of electrolytic reduction, even if hydrochloric acid soaks
It is difficult for the encroachment part to discolor and it is difficult to determine the immersion distance.
There is Therefore, carefully observe with a microscope
I chose For comparison, the oxidation treatment without electrolytic reduction is shown in FIG.
The results of examining the hydrochloric acid resistance of the as-prepared sample are also shown.
It was If oxidation treatment (curve iii) takes 1 h, 2
Hydrochloric acid infiltration of about 00 μm was observed, and the immersion time was increased.
The amount of hydrochloric acid infiltration increases monotonically with addition. Against this
If electrolytically decomposing (curve iv), the
The formed film is not soaked with hydrochloric acid even after 6 hours.
Note that FIG. 6 also shows the results after immersion for 15 hours.
The result shows that the electrolytic reduction is insufficient (0.025 mA / cm²)system
Then, a little hydrochloric acid soaked, but other electrolysis
The reduced sample was not soaked with hydrochloric acid. In any
However, the electrolytic reduction film is more
It is clear that the hydrochloric acid resistance can be greatly improved. The solution was reduced and precipitated at a liquid temperature of 25 ° C. without stirring.
The appearance of the sample when exposed to light is 1.25 mA / cm²Reduced by
In this case, the appearance of the reduction film is blackish brown (dark brown). 0.12
5 mA / cm²When reduced with, the appearance is brown,
The appearance of the sample that has been oxidized only is similar. 0.0625mA / c
m²When reduced with
It approaches the color tone of the resulting treated film. Note that the current density
0.025mA / cm²When turned on, the appearance is dark brown (black and)
It becomes a color, but this is a reduction reaction even if the energization time exceeds 10 hours.
This is because the response did not reach the end point and was interrupted. Each reduction film
Was observed with a scanning electron microscope,
1.25mA / cm²The sample reduced by
It is close to the surface shape of the processed sample. 0.125mA / cm²Place
Compared with the case, the particles grow slightly, but the particles grow larger.
0.0625mA / cm²Then, it was treated before and after the oxidation treatment.
It approaches the surface shape afterwards. Furthermore, 0.025 mA / cm²Return with
In case of original, 0.0625mA / cm²When reduced by
Than 0.125 mA / cm²And 1.25mA / cm²Article between
It is close to the surface shape of the reduction film obtained in this case.
0.025mA / cm²The sample prepared by
Because of that. The solution was reduced and precipitated under the conditions of a liquid temperature of 50 ° C. and stirring.
The appearance of the sample when exposed to light is 1.25 mA / cm²Reduced by
In this case, the appearance has a shade of dark brown and brown
Presents. 0.125mA / cm²Appearance when reduced with
Turns brown. 0.0625mA / cm²In case of reduction with
It becomes reddish brown, and the treated film obtained in the first half of the oxidation treatment
It is close to the color. Furthermore, 0.025 mA / cm²When returned by
If it is, it seems that it will be closer to copper color, but 0.025 without stirring
mA / cm²The electrolytic reduction is not
Sufficient and turned yellow red. Surface of sample used here
As a result of examining the shape with a scanning electron microscope, 1.
25mA / cm²The surface shape of the sample reduced by
It is similar to the surface shape of the sample. 0.125mA / cm²Then
Fine reduced copper crystal grains of 0.1 μm or less are observed
But 1.25mA / cm²Compared with the case of reducing with
The number is small and it becomes smooth. 0.06
25mA / cm²In the sample reduced by, the reduced copper crystal grains are large.
It grows well and mixes with crystal grains of 0.1-0.5 μm
Large crystal grains of about m are also recognized. 0.025mA / c
m²The surface shape of the sample reduced with 0.0625mA / cm
²Is almost the same as the case of the film obtained by reduction treatment at
It The sample whose surface is covered with fine crystals is peeled off.
The strength is high, and the adhesive property is strong on the surface shape of the reducing film.
It is admitted that it depends heavily. Next, under the conditions that the liquid temperature is 25 ° C. and no stirring is performed, each electrode is
Reflection electron diffraction image of the reduced film obtained at the flow density and
Observe in the same manner when the liquid temperature is 50 ° C and stirring is performed.
Results, and the reflection electron diffraction image of the chemically oxidized film
In order to analyze the pattern of the diffraction line to be examined
Cu, Cu based on STM card and Au standard sample₂O,
CuO and Cu₃(PO_Four)₂The diameter of each diffraction line was calculated.
As a result, C was found in both the samples of the oxidation treatment film and the reduction film.
u and Cu₂O 2 is slightly recognized. Originally, reduction
It aims at the complete metal copperization of the film, but as such
I was unavoidable and remained unavoidably. The above is one embodiment of the present invention
Of course, the conditions are not limited to these. (Measurement result of direct reflectance) The surface reflectance is
1.25mA / cm², Liquid temperature 25 ℃, non-stirring conditions, the above method
The sample of the present invention was obtained by electrolytic reduction according to. this
The appearance of the sample is dark brown and matte. Copper base as a comparative example
Piece (with natural oxidation, copper color), high temperature water as Comparative Example 2
A copper piece (copper color, glossy) by elementary reduction is used. Measurement result
Is as shown in FIG. In FIG. 7, the curve iv is the direct inverse of the sample of the present invention.
The emissivity and the curve v also show the diffuse reflectance. Also the curve vi
Is the direct reflectance of the sample of Comparative Example 1, and curve vii is
The diffuse reflectance is shown. Furthermore, the curve viii is a direct comparison of the sample of Comparative Example 2.
As for the reflectance, the curve viv also shows the diffuse reflectance. In addition,
The diffuse reflectance is trapped by the light diffuser 22 of FIG.
Instead, it was measured. As is clear from FIG. 7, the sample of the present invention is
The high direct reflectance that should be seen on the surface of loose metallic copper is not seen.
I can't. A more specific application example of the present invention will be described below.
Bell. Example 1 An embodiment of the present invention will be described below with reference to FIG. Both sides of the glass fiber reinforced epoxy resin plate 28
The surface of (A), which is obtained by thermocompression-bonding the copper foil 29 to the above, is shown below.
Such a composition NaOH 5g / l Na₃PO_Four・ 2H₂O 10g / liter NaClO₂30 g / liter Of the copper foil 29 after being treated with a phosphoric acid-based aqueous solution containing
A copper oxide film 30 was formed on the surface (B). Then, after washing with water,
The copper oxide film 30 is formed to the extent that the adhesiveness with the resist described later is not damaged.
Was electrolytically reduced to obtain an electrolytically reduced metal layer 2 (C). This electrolytic reduction uses N as a liquid for electrolytic reduction.
Use a liquid adjusted to pH 12.0 with aOH and adjust the liquid temperature.
25 ℃, reducing current density 1.25mA / cm²And then
A stainless plate is used for the pole, and it is formed on the copper surface.
The oxide film was subjected to a reduction treatment. Next, the electrolytic solution attached to the reduction-treated film is
After washing with water, dry well and dry film 31 on it
To form a resist pattern (D), and then
Ingredients CuSO_Four・ 5H₂O 7g Ethylenediamine tetraacetic acid 30g 37% HCHO 3 ml Add NaOH to adjust the pH to 12.5 Polyethylene glycol 20ml (Average molecular weight 450) 2,2 'dipyridyl 30 mg Plating solution adjusted to a concentration that can be obtained by dissolving
Thickness of copper 32 as a circuit conductor on the circuit part using
(E). As a result, the chemical plating solution
There was no deposition of copper on the non-circuit part due to penetration. Next, the resist pattern of the dry film 31
(F) and then the composition as shown below FeCl₃400 g / liter Conc · HCl 20 ml / liter The copper foil 29 in the non-circuit part is etched with an etching solution containing
Glass fiber reinforced epoxy resin substrate 28
Copper wiring was completed by leaving copper 32 on top (G). The obtained copper wiring pattern has a copper conductor width (μ
m) / conductor spacing (μm) is 49/51, which is
The corresponding resist pattern shape ratio of 50 used
Close to / 50 and have good desired pattern accuracy
I understood. Example 2 Of the glass fiber reinforced epoxy resin plate 28 in Example 1
Same as Example 1 except that a polyimide plate was used instead
It was carried out according to the method and conditions. As a result, the obtained copper wiring
The said ratio of patterns is 49/51, which is
50/5 of the corresponding register pattern shape
It was found to be close to 0 and have good pattern accuracy.
It was Example 3 In Example 1, a liquid was used instead of the dry film resist.
-Like resist is used and the pH of the electrolyte is 6.0.
Except for this, the same method as in Example 1 was used. That conclusion
As a result, the above-mentioned ratio of the obtained copper wiring pattern is 48/52.
This is the resist pattern shape used.
The pattern accuracy is close to 50/50, which corresponds to
Found to have. Example 4 In Example 1, as a liquid for the oxidation treatment of the copper foil surface,
Instead of an acid-based aqueous solution KMnO_Four10 g / liter NaOH 10g / l After treating the copper foil surface with an aqueous solution having the following composition:
Otherwise, the same method and conditions as in Example 1 were used. That conclusion
As a result, the above ratio of the obtained copper wiring pattern is 49/51.
This is the resist pattern shape used.
The pattern accuracy is close to 50/50, which corresponds to
Found to have. Electrolytic reduction reaction of copper oxide film during electrolytic reduction
The response is as follows. That is, the main reaction is
A response mechanism is possible. [0073] [Equation 11] As the pH of the electrolytic reducing solution, a pH of 6 or more is used.
preferable. The reason is that when the pH is below about 5.5, [0075] [Equation 12] A reaction such as the above proceeds rapidly, and
If the substrate with the oxide film is immersed in the electrolyte,
This is because it is difficult to obtain a shaped electrolytic reduction film. The copper alloy obtained by each of the above examples
The wire plate is used during its formation in the film after electrolytic reduction.
Phosphorus, manganese or salt depending on the above-mentioned oxidation treatment liquid
It was found to contain elemental or oxygen. In each of the above-described embodiments, both surfaces of the insulating substrate 28 are formed.
Although it was explained that the circuit is formed, the circuit is formed only on one side.
Of course, the present invention can be applied to the case of forming
Is. In addition, the substrate 28 is obtained by thermocompressing a copper foil 29.
However, instead of this, chemical plating of copper
It is also possible to use an insulating substrate having a thin layer on its surface. Comparative Example 3 For comparison, the electrolytic reduction process (C) of Example 1 was performed.
The process of the preceding example was performed under the same conditions as in Example 1 except that it was not specified.
Copper wiring on the glass fiber reinforced epoxy resin board
Once formed, the acid formed on the copper foil during chemical plating
Part of the copper ions in the oxide film are reduced, and subsequently,
Reduced deposition of copper ions in the plating solution on the circuit
became. As a result, the above ratio of the copper wiring pattern is 43.
/ 57, which is the resist pattern shape used
Which is very different from the corresponding 50/50 ratio
The pattern accuracy was poor. Example 5 An embodiment of the present invention will be described with reference to FIG. Copper foil on both sides
29 of the glass fiber reinforced epoxy resin plate 28 thermocompression bonded
Copper 32 is chemically plated on copper foil 29 as a circuit conductor.
After depositing to the required thickness, the surface of copper 32 is shown below.
Such a composition NaOH 5g / l Na₃PO_Four・ 2H₂O 10g / liter NaClO₂30 g / liter On the surface of the copper 32 by treating with a phosphoric acid-based aqueous solution containing
After forming the copper oxide film 30 (A) and washing with water, the copper oxide film 30 is removed.
Electrolytic reduction is performed to the extent that the adhesion with the prepreg described below is not impaired.
(B). Electrolytic reduction is NaOH 5g / liter aqueous solution
(PH12), 2mA / cm²It was carried out in. Oppositely
Is a stainless plate. Next, a dry layer is formed on the electrolytic reduction metal layer 2.
The film 31 forms a register pattern (C).
Aqueous ferric chloride solution FeCl₃400 g / liter Cone / HCl 20ml / liter Etches copper (29 and 32) in non-circuit area
Remove (D), then with dry film 31 still on
In this state, again using the same phosphoric acid-based aqueous solution as above, copper
Form a copper oxide film 33 on the side surface of the wire (E), and then dry
The film 31 was removed with methylene chloride or the like.
(F). In this way, the single plate with the copper wiring is
Epoxy resin prepreg 34 reinforced with lath fiber
Stack with the interposition of
Bonded by pressure (However, for the outermost veneer, copper is placed on the outermost side.
Use the same copper foil 29 without wires),
A through hole H that penetrates a predetermined circuit conductor is opened.
(G). In this state, it is formed on the side surface of the copper wiring 32.
The exposed copper oxide film 33 is not exposed on the inner surface of the through hole,
It is in a position isolated from this. Then in the through hole
The surface is coated with a catalyst for chemical plating, and then chemically plated.
Copper 32 on the inner surface of the through hole and the entire outermost layer
Plate to the required thickness as a circuit conductor, then dry
After forming a resist pattern on the outermost layer by the film
Copper on the non-circuit part is removed by etching, and then dry
The film was removed to complete a multilayer wiring board (H). The structure of the multilayer wiring board completed in this way
As shown in FIG. 9 (H), the flat surface of the copper conductor is
It is not covered with copper oxide, and only its side surface is made of copper.
It is covered with an oxide. In the above process, the multilayer wiring board
Is a chemical plating pretreatment for the through hole and outermost layer.
In the meantime, the copper oxide film layer was
There is no direct contact. Therefore, the above process was adopted.
The multi-layered wiring board created in this way has excellent hydrochloric acid resistance and
The prepreg and copper wiring have high adhesion, which in turn prevents wiring
It was possible to make it high. Hydrochloric acid is actually measured
The strength is 48 times higher than that of the sample without electrolytic reduction.
Strength was 1.1 kg / cm. Example 6 Organic resin for the substrate and prepreg in Example 5
And use polyimide instead of epoxy, and
The pH was adjusted to 6.0 and otherwise the same method as in Example 5 was used.
It was carried out. As a result, compared with the sample without electrolytic reduction,
Hydrochloric acid is 50 times, and copper wiring of organic resin
Peel strength is 1.2Kg / cm, and all points are excellent
Multi-layer wiring board with high-density wiring pattern
Was obtained. Example 7 In Example 5, a liquid register was used instead of the dry film.
Stroke, and the pH of the electrolyte is 6.0, otherwise
Was carried out by the same method as in Example 5. As a result, salt resistance
Has a high-density wiring pattern with excellent acidity and adhesion
A multi-layered wiring board was obtained. Hydrochloric acid resistance is 45 times, peel strength
The degree was 1.2 Kg / cm 2. Example 8 As a solution for oxidizing the surface of the copper foil 29 in Example 5
Instead of the phosphoric acid-based aqueous solution KMnO_Four10 g / liter NaOH 10g / l Other than treating the copper foil surface with an aqueous solution of
Was carried out by the same method and conditions as in Example 5. That conclusion
High-density wiring pattern with excellent resistance to hydrochloric acid and adhesion
A multi-layer wiring board having a resin was obtained. Hydrochloric acid resistance is 47 times,
The peel strength was 1.1 kg / cm. In the above, hydrochloric acid resistance and peeling
The strength is evaluated by the following evaluation method. Hydrochloric acid resistance: Each sample was treated with (1 + 1) salt
Immerse in an acid aqueous solution for 1 hour to dissolve the copper oxide film in hydrochloric acid.
The widths were compared, and the wider the width, the more defective. Peel Strength: Well known and commonly used
An evaluation method was used. That is, the width of the copper film becomes 10 mm
Part of the copper film that has been peeled off and removed
And the resin part of the board are fixed to the jig of the tensile tester.
The copper film vertically from the resin plate at a speed of 10 cm / min.
The unit width is the stress P (Kg) when peeling off and peeling the film.
The value is expressed in units of (cm) (PKg / cm). The process of FIG. 9A in each of the above embodiments
In place, the copper layer 32 to be a circuit is an alternative to chemical plating.
Alternatively, the copper foil 29 may be attached by electroplating. Also copper foil
Description is made assuming that the insulating substrate 28 in which 29 is thermocompression bonded is used.
However, instead of the copper foil 29, a thin layer of copper was chemically plated.
An insulating substrate provided on the outer surface may be used. In each of the above embodiments, they should be laminated.
It is explained that each veneer has circuits on both sides.
However, if desired, only one side for all or some veneers
A circuit may be formed in. Depending on the circuit design needs, the outermost surface may be
Need not form copper wiring. Example 8 Chemically deposit copper 32 on the double-sided copper-clad glass epoxy resin plate 28.
After thickening by plating, the surface of copper 32 is shown below.
Copper such as benzotriazole and phosphoric acid aqueous solution
Form an oxide film and a metal protective film on the surface of the
Electrolytically reduce the membrane. [0094] Benzotriazole 100ppm NaOH 5g / l Na₃PO_Four・ 2H₂O 10g / liter NaClO₂30 g / liter Next, a resist pattern is formed with the dry film 31.
And then ferric chloride aqueous solution FeCl₃350 g / liter Conc, HCl 20 ml / liter The copper of the non-circuit part by etching, and then dry
With the film 31 still attached, again use phosphoric acid-based water.
An oxide film is formed on the side surface of the copper wiring using the solution, and then the dry film is formed.
Release the film. Next, copper on both sides is copper
Leave the foil as it is, i.e. dry film on one side.
After masking the entire surface, and then chemically plating the remaining one side,
A substrate processed according to the steps of (B) to (F) of FIG.
To achieve. Electrolytic reduction conditions are NaOH 5g / liter aqueous solution
With 0.2 mA / dm²It was carried out in. Example 9 Example 8: Organic resin for substrate and prepreg
As a substitute for the epoxy resin, polyimide resin is used.
Except for this, the same method as in Example 8 was used. That conclusion
High density wiring pattern with excellent resistance to hydrochloric acid and adhesion
A multi-layer wiring board having a wiring board is obtained. Example 10 In Example 8, a single-sided copper clad plate was used as the outermost layer. So
Except for this, the same method as in Example 8 was used. That conclusion
High-density wiring pattern with excellent resistance to hydrochloric acid and adhesion
A multi-layer wiring board having a resin was obtained. Example 11 In Example 8, instead of the dry film, a liquid register
Using the same procedure as in Example 8 except that
did. As a result, high density with excellent hydrochloric acid resistance and adhesion
A multilayer wiring board having a wiring pattern was obtained. Example 12 In Example 8, as the liquid for the oxidation treatment of the copper foil surface,
Instead of phosphoric acid type liquid KMnO_Four15 g / liter NaOH 15g / l Was used to treat the surface of the copper foil. Otherwise the same as Example 8.
The same method was used. As a result, hydrochloric acid resistance and adhesion
Multi-layer wiring board with a high-density wiring pattern with excellent properties
Was obtained. Example 13 In Example 8, benzotriazo was added to the phosphoric acid-based aqueous solution.
1000ppm of water to form an oxide film on the surface of copper
It was Other than that was carried out by the same method as in Example 8. So
As a result, high-density wiring pattern with excellent hydrochloric acid resistance and adhesion
A multilayer wiring board having turns was obtained. Example 14 In Example 8, benzotriazo was added to the phosphoric acid-based aqueous solution.
Of thiodiethylene glycol in place of 100 ppm
It carried out by the same method as Example 8 except having added. That
As a result, both hydrochloric acid resistance and adhesiveness are excellent.
It was Example 15 Chemical plating of copper 32 on double-sided copper-clad glass epoxy resin plate
After thickening the surface of the copper with
Acidic aqueous solution NaOH 5g / l Na₃PO_Four・ 2H₂O 10g / liter NaClO₂30 g / liter To form an oxide film on the surface of copper, wash it with water, and then remove the oxide film.
Electrolytic reduction. Electrolytic reduction conditions are NaOH 5g / l aqueous solution
Current density of 0.2 mA / dm²Done in. Next, the reduction film
An aqueous solution of phosphoric acid as shown below on the surface NaOH 0.5g / l Na₃PO_Four1.0 g / liter NaClO₂3.0 g / liter Thereby forming an oxide film layer. The film thickness at that time is 100Å
And Next, the dry film 31 is used for resist pattern
And then a ferric chloride-based aqueous solution FeCl₃40 g / liter Conc · HCl 20 ml / liter To remove the copper 32 in the non-circuit area by etching.
With the rye film 31 still attached, phosphoric acid
Form an oxide film on the side surface of the copper wiring using the aqueous solution of
Remove the dry film. After that, pre-prepare this
Prepreg by heating and pressurizing with a hot press
Let it harden. In addition, one side of the copper clad plate on both sides is in the state of the copper foil as it is.
That is, one side is entirely masked with a dry film,
Next, after chemical plating on the remaining one side, FIG.
A substrate processed according to the step (F) is prepared. Example 16 Example 15: Organic resin for substrate and prepreg
Use polyimide resin instead of epoxy resin as oil,
Other than that was carried out by the same method as in Example 15. That
As a result, high-density wiring pattern with excellent hydrochloric acid resistance and adhesion
A multilayer wiring board having a core was obtained. Example 17 In Example 15, a single-sided copper clad plate was used as the outermost layer.
Other than that was carried out by the same method as in Example 15. That
As a result, high-density wiring pattern with excellent hydrochloric acid resistance and adhesion
A multilayer wiring board having a core was obtained. Example 18 In Example 15, the liquid film was used instead of the dry film.
The same method as in Example 15 was used except that a cyst was used.
Carried out. As a result, it has excellent hydrochloric acid resistance and adhesion.
A multilayer wiring board having a high-density wiring pattern was obtained. Example 19 In Example 15, as a liquid for the oxidation treatment of the copper foil surface
Instead of the phosphoric acid type liquid KMnO_Four15 g / liter NaOH 15g / l Was used to treat the surface of the copper foil. Otherwise the same as Example 1.
The same method was used. As a result, hydrochloric acid resistance and adhesion
Multi-layer wiring board with a high-density wiring pattern with excellent properties
Was obtained. Example 20 One side of the metal copper foil (film thickness 50 μm) was washed with 1 liter of distilled water.
Or CuCl₂40 g HCl (35%) 300 ml The surface of the copper foil is immersed in a liquid containing
After roughening, per liter of distilled water, Na₃PO_Four・ 12H₂O 15g NaClO₂25 g NaOH 10g It is immersed for 120 s at 70 ° C in a liquid containing
A copper compound layer is formed on the surface. Next, 1 liter of distilled water
Around NaOH 10g Current density of 0.5 at a liquid temperature of 25 ° C.
mA / cm²Electrically reduced. Then with a glass cloth
Copper compound layer using reinforced polyimide prepreg
Using the copper foil that has undergone the reduction treatment, the reduction treatment surface is the prepreg side.
Glued to. Adhesive is heated to 170 ℃, 25Kg
/cm²It was carried out under the condition that the load of 60 min was applied. After bonding
Adhesion of copper foil to polyimide resin at room temperature
It was 1.1 Kg / cm 2, which was good. Also, for hydrochloric acid resistance
After bonding, cut a part and polish the cross section
After polishing with paper (# 1000), 17.5% salt at room temperature
Immerse in the acid solution, and after 3 hours, remove the copper foil and remove hydrochloric acid.
Examination of discoloration due to penetration showed no discoloration, and hydrochloric acid resistance
The property was good. Alcohol in 1 liter of 17.5% hydrochloric acid
Blowing gon gas at a flow rate of 1 liter / min for 1 hr,
After that, when the reduction-treated copper foil was dipped, the reduction treatment film
Did not completely disappear after 30 seconds. Reflection type electric
The diffraction pattern by the sagittal diffraction method is mainly used for metallic copper foil.
The orientation plane is the (100) plane, and the main orientation plane of the reduction film is (1
00) face. Also, check for copper oxide on metallic copper foil.
Was difficult, but it was easy to confirm the copper oxide from the reduced film.
there were. When the surface roughness of the reduced film was investigated,
The cut defined by the surface roughness of JIS B 0601
Reference length L of surface₂Is 100 μm, Rz is 2 μm
there were. Example 21 Example 20: Polyresin reinforced with glass cloth
Reinforced with glass cloth instead of Mido prepreg
Using epoxy prepreg, heating temperature 170 ℃, load
20 kg / cm²Adhesion with heating time of 80 min
did. Others were carried out under the same conditions as in Example 20. Glued
Peel strength of copper foil against epoxy resin of copper-clad epoxy board
Degree is 1.3Kg / cm²And the infiltration with hydrochloric acid was not recognized.
There wasn't. The surface roughness of the reduction film was the same as in Example 20.
there were. The solubility in hydrochloric acid was examined in the same manner as in Example 20.
The result was about the same as in Example 20. Example 22 In Example 21, when reducing the copper compound, the current density
0.5 mA / cm²Instead of 2.5mA / cm²Carried out in
It was It carried out on the same conditions as the other Example 20. Glued copper
Peel Strength of Copper Foil against Epoxy Resin of Tension Epoxy Board
Is 1.2 kg / cm²There is no infiltration with hydrochloric acid,
Strength and hydrochloric acid resistance were both good. Of reduction membrane
Surface roughness is defined by the surface roughness of JIB B 0601.
When the reference length L of the cross section is 100 μm, Rz is
It was 1.5 μm. In addition, the solubility test for hydrochloric acid
The results were the same as in Example 20. Example 23 In Example 20, CuC was used as the etching liquid for the copper foil.
l₂-1 liter of distilled water instead of HCl-based etching solution
Per le FeCl₃350 g HCl (35%) 20 ml The surface of the copper foil was roughened with a liquid containing. Other Example 2
It carried out on the same conditions as 0. For bonded copper-clad epoxy resin
The peel strength of the copper foil is 1.0 kg / cm²And in hydrochloric acid
There is no penetration, and the peel strength and hydrochloric acid resistance are both
It was good. The surface roughness of the reduction film is JIB B 06.
The reference length L of the cross section defined by the surface roughness of 01 is 10
At 0 μm, Rz was 2.5 μm. Hydrochloric acid resistance
Was the same as in Example 20. Example 24 In Example 21, a copper compound layer is formed on the copper foil surface.
When using Na₃PO_Four-NaClO₂-Uses NaOH-based liquid
Instead of 1 liter of distilled water Cu (CH₃COO)₂・ H₂O 50g CH₃COONH_Four100g NH_FourCl 10g CuSO_Four5 g NH_FourOH (28%) 10 ml The surface of the copper foil is dipped in a liquid containing
A copper compound layer is formed on top. Same conditions as in other Example 21
It was carried out in. For epoxy resin of bonded copper-clad epoxy board
The peel strength of the copper foil is 1.2 kg / cm²And in hydrochloric acid
There is no penetration, and the peel strength and hydrochloric acid resistance are both
It was good. The surface roughness of the reduction film is JIS B 0601.
The reference length L of the cross section defined by the surface roughness is 100μ
At m, Rz was 1.5 μm. Hydrochloric acid resistance is real
The same as in Example 20. Example 25 In Example 21, a copper compound layer is formed on the copper foil surface.
When using Na₃PO_Four-NaClO₂-Uses NaOH-based liquid
Instead of doing UV rays, 5000 mJ / cm²Irradiating
Thus, a copper compound layer is formed on the surface of the copper foil. Other implementation
It carried out on the same conditions as Example 21. Bonded copper clad epoxy board
The peel strength of copper foil against the epoxy resin of 1.1kg / c
m²It does not soak in hydrochloric acid and has peel strength and salt resistance.
The acidity was good. The surface roughness of the reduction film is JI
Reference of cross section defined by surface roughness of S B 0601
When the length L is 100 μm and Rz is 1.8 μm,
It was Hydrochloric acid resistance was similar to Example 20. Comparative Example 4 In Example 20, a copper compound layer is formed on the surface of the copper foil.
After that, the polyimide prep reinforced with glass cloth
Using a leg, bond with the copper compound layer facing the prepreg side
did. Others were carried out under the same conditions as in Example 20. Glued
Peel of copper foil to polyimide resin of copper clad polyimide board
Le strength is 1.3 kg / cm²Yes, the peel strength characteristics are excellent
However, the amount of penetration from the side with hydrochloric acid is 120 μm.
Yes, the hydrochloric acid resistance was poor. The surface roughness of the reduction film is
Of the cross section defined by the surface roughness of JIS B 0601
When the reference length L is 100 μm and Rz is 1.5 μm
there were. As in Example 20, the solubility in hydrochloric acid was increased.
As a result of investigation, the copper compound layer completely dissolved in 5 seconds.
It was Comparative Example 5 A method of electrically reducing the copper compound layer in Example 20
Instead of the law, per liter, HCHO (37%) 200 ml It was chemically reduced with a liquid containing. Other than Example 20
It carried out on the same conditions. Bonded copper-clad polyimide board poly
Peel strength of copper foil against imide resin is 0.1 kg / cm²
Yes, the peel strength characteristics were poor. However, hydrochloric acid
There was no penetration from the side. Of the surface of the reduction membrane
Roughness is defined by the surface roughness of JIS B 0601.
When the reference length L of the cross section is 100 μm, Rz is 0.5
was μm. Further, as in Example 20, dissolution in hydrochloric acid was performed.
When the desolvability was examined, it was about the same as in Example 20.
It was [0118] According to the present invention, it is possible to bond the copper foil and the resin together.
Therefore, the unevenness of the surface of the copper foil is kept low (JIS B 06
The reference height L of the cross section defined by the surface roughness of 01 is 10
At 0 μm, Rz is 6 μm or less)
0.3 kg / cm²Above, and the characteristics excellent in hydrochloric acid resistance
It is possible to have it.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a metal-resin composite according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the principle of an electrolytic reduction device. FIG. 3 is an explanatory diagram of metal deposition by an electrolytic reduction method. FIG. 4 is an optical system diagram of a color analyzer. FIG. 5 is an adhesion characteristic diagram of an electrolytic reduction film. FIG. 6 is a hydrochloric acid resistance characteristic diagram of an electrolytic reduction film and a chemical oxidation treatment film before that. FIG. 7 is a surface reflection characteristic diagram. FIG. 8 is a process drawing of forming a printed board. FIG. 9 is a process drawing of forming a multilayer board. [Explanation of Codes] 1 ... Base metal layer, 2 ... Electrolytic reduction metal layer, 3 ... Resin layer, 4
... 1st uneven | corrugated part, 5 ... 2nd uneven | corrugated part, 6 ... Sample piece, 7 ...
Counter electrode, 8 ... Electrolyte solution, 10 ... Electrolyte tank, 28 ... Glass fiber reinforced resin plate, 29 ... Copper foil, 30, 33 ... Copper oxide film, 31
... Dry film, 32 ... Copper, 34 ... Prepreg.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshikazu Narahara             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Takeshi Shimazaki             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Inside Hitachi Research Laboratory, Hitachi, Ltd.

Claims (1)

[Claims] 1. The appearance is matte and the surface hue is Munsell color chart 7.
The range is 5RP to 7.5Y, the brightness is 7 or less,
A metal copper foil having a metal copper surface having a saturation of 12 or less. 2. A step of oxidizing the surface of the metal layer to form a metal oxide film, and reducing the surface of the metal oxide film obtained in the step, and the hue of the surface is in the range of Munsell color chart 7.5RP to 7.5Y, A method for producing a metal copper foil, comprising a step of forming a reduced metal surface layer having a lightness of 7 or less and a saturation of 12 or less.