JP3269818B2 - Surface roughened copper, method for producing the same, and printed circuit board using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface roughened copper, a method for producing the same, and a printed circuit board using the surface roughened copper.

[0002]

2. Description of the Related Art In recent years, the number of multilayer printed circuit boards used has been increasing with the miniaturization of circuits and the increase in frequency. The surface-roughened copper foil used for this purpose is required to have a low delay speed at a high frequency and have an adhesive strength corresponding to a reduction in area.

In the conventional method for producing a roughened copper foil, a roughened copper foil is rolled into a negative pole, copper is used as a positive pole, and a relatively low current density is used to first perform roughening plating on only one side, and then roughening plating is performed. It was usual that the non-surfaced rear surface was similarly subjected to surface roughening plating.

However, since the surface roughening plating is performed at a low current density, it takes a long time to finish the plating, the manufacturing cost increases, and the control of the plating solution is not easy.
In addition, as is apparent from the schematic cross-sectional view of the copper foil surface subjected to the conventional roughening plating shown in FIG. 1, the unevenness of the plating surface forms a large undulation, so that it is used for a multilayer printed circuit board. However, there is a problem that a short-circuit failure or the like occurs. Further, there is a problem that the adhesive strength between the roughened copper foil and the resin substrate is also weak. Also, the surface area of the roughened copper foil is small, which is disadvantageous for making a built-in capacitor.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a roughened surface copper capable of maintaining the adhesion between a copper foil and a resin by a simple and inexpensive method in order to solve the above-mentioned conventional problems. I do.

[0006]

In order to achieve the above object, the surface roughened copper of the present invention is a copper foil or a copper plate having a surface layer portion provided with unevenness having a height of 1 to 20 μm. The space density occupied by the uneven portions is not less than 10% and not more than 90%.

[0007] When the height of the unevenness of the surface layer portion is less than 1 µm, the adhesive strength is reduced. Further, the space density of the uneven portion is 10
%, Or more than 90%, the adhesive strength decreases.

According to the present invention, the adhesion between the nonwoven fabric such as glass fiber and the printed board made of resin can be enhanced by roughening the surface of the copper foil constituting the multilayer printed board, and even in the GHz (GHz) band. It can be used. The present invention can also be used for a method for producing a surface-roughened copper foil that requires bonding properties with a resin such as an electrode for a PTC characteristic current protection element formed by mixing and curing carbon and polyethylene.

Further, the method for producing a roughened copper according to the present invention comprises:
At least one selected from the group consisting of sodium chloride, potassium chloride, sodium nitrate, potassium nitrate, magnesium sulfate, sodium carbonate and sodium hydrogen carbonate
Reacts with various salts and copper ions to form poorly soluble compounds
The surface roughness of copper surfaces of copper foil or copper plate obtained by etching in an electrolyte containing a may anions, added the anion
In the electrolyte having an addition amount of 0.0090% by mass or less.
It is characterized by performing etching once . The amount of the salt that supplies anions that react with copper ions is preferably 0.01% by mass to 5% by mass. Also, the amount of other salts added,
It is preferably from 0.01% by mass to 5% by mass.

The anion is at least one selected from the group consisting of carbonate ion, fluorine ion, hydrogen carbonate ion, hydroxide ion, phosphate ion, pyrophosphate ion, iodoate ion, oxalate ion, formate ion and metaphosphate ion. One type is preferred.

Further, the etching is preferably an AC etching.

Further, the AC frequency used for the AC etching is preferably 50 Hz or less.

It is preferable to add a small piece of carbon dioxide gas or dry ice by bubbling as an additive to the electrolytic solution. Thereby, the etching proceeds further.

Further, it is preferable that the roughened copper produced by the above method is treated or etched in an acidic or alkaline solution.

Next, the printed circuit board of the present invention includes the above-described surface roughened copper as a conductor. In addition, a capacitor can be built in the printed circuit board.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Electrolytic etching is usually performed to smooth the surface of a metal like electrolytic polishing. The reason is that when a metal plate and a counter electrode plate are placed in an electrolytic solution in parallel and electrochemically etched using the metal plate as the anode, if there is unevenness in the metal, the current will concentrate on the protrusion near the counter electrode. It is. For this reason, it is difficult to form irregularities by etching, except for a metal such as aluminum, which produces an oxide when it becomes an anode.

In the present invention, by adding an anion capable of forming a hardly soluble compound by reacting with copper ions in the electrolytic solution, the hardly soluble compound is added to the projections where the amount of copper ions increases during electrolytic etching. The recesses that are generated and hinder the etching and the recesses where the anions do not easily reach are easily etched, so that the etching can be roughened.

Further, in order for the three-dimensional shape of the surface layer portion of the etching foil to uniformly form irregularities of a polygonal prism, a truncated polygon or a polygonal pyramid, AC etching is more advantageous than DC etching in terms of the opportunity for generation of etch pits. is there.

In general, when the frequency of the AC etching is lowered, the interval between the etch pits is increased and irregularities are formed at a wide interval, and when the frequency is about 1 Hz, irregularities having a considerably large interval are obtained. On the other hand, when the etching frequency is increased, the interval between the etch pits is reduced, and fine irregularities are obtained. If the etching frequency is further increased to exceed 50 Hz, the progress of the etching is practically stopped.

The salt used for the electrolytic solution for etching may be a salt having a halogen ion which easily forms a complex with a copper ion. In addition, since a combination of a neutral salt and a compound that is difficult to dissolve with copper ions often forms a precipitate such as copper oxide or basic copper carbonate on the surface, it is treated with an acid or an alkali after etching or etched in an acid or an alkali. It is better to remove the precipitate by performing

Further, the roughened surface formed by this etching can control the unevenness considerably freely by the liquid composition, frequency, current density and re-etching, so that a surface shape and roughness suitable for the purpose can be obtained.

Since the three-dimensional shape obtained by etching is often a polygonal prism, in order to form a polygonal trapezoid in which a capacitor can be easily formed, 3000 mol / m ³ of sodium hydrogen carbonate, 3000 mol / m ³ of NaCl,
Etching can be performed again with 2,000 mol / m ³ HCl or 3000 mol / m ³ NaCl bubbled with carbon dioxide gas.

FIG. 4 is a schematic view of an etching tank used in the present invention. In FIG. 4, 1 is an electrode, 2 is another electrode which is a sample, 3 is an electrolyte containing an additive, and 4 is a power source.

[0024]

The present invention will be specifically described below with reference to examples.

Example 1 0.2% by mass of ammonium carbonate was added to water as an additive to supply 3000 mol / m ³ of sodium chloride and an anion capable of forming an insoluble compound by reacting with copper ions. In the dissolved electrolyte, copper foil was used for the electrode on the sample side, and carbon was used for the other electrode.
When etching was performed at a current density of 170 mA / cm ² for 5 minutes with an AC current of z, the surface roughness Ra was 10 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 36.
It became 3N. A similar tendency was observed with epoxy and rubber adhesives. When the frequency exceeded 50 Hz, etching did not proceed. In addition, it was observed that the higher the current density, the larger the surface roughness. When the pH was adjusted to pH 4 with hydrochloric acid and etched, the tensile strength was 26.5 N, but it was 14.7 N for PH 1 and 21.6 N when it was adjusted to PH 11 with sodium hydroxide. Thus, the tensile strength can be controlled by the PH.

The effect was effective when the amount of ammonium carbonate added was 0.01% by mass or more. Ammonium bicarbonate had a similar effect. Similar effects were obtained by adding at least one of the additives described in claim 3 as an additive in an amount of 0.01 to 5% by mass. 請 also for salt in the electrolytic solution
Claim 2 may be replaced with another one, or NaCl and K
Even when used as a mixture such as Br, there was no significant difference. It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. The same effect was obtained with a direct current of 0.3 Hz or less, but process control was difficult. At 0.3 to 5 Hz, the result was satisfactory and almost the same result as at 1 Hz was obtained. Above 5 Hz, the etching amount decreased with increasing frequency, and above 50 Hz, the etching was practically stopped. The etching waveform is preferably a sine wave, but a rectangular wave, a sawtooth wave, and various pulse waves were also good.
There was no significant difference even with bias, but management became difficult.

Regarding the current density, a small one naturally takes a long time, and a large one has a problem such as heat generation.
10 mA / cm ² to 700 mA / cm ² were appropriate. Regarding the etching time, if the etching time is short, the etching will not proceed, if it is long, the cost will not match, and the space density occupied by the unevenness in the surface layer of the copper foil is less than 10%, the capacitor capacity due to the decrease in adhesion strength and surface area However, there was a problem such as a decrease in the temperature, and about 5 seconds to 1 hour was appropriate. As the number of etchings increases, the additive may be added in an amount corresponding to the consumption amount. Bubbling of carbon dioxide gas or small pieces of dry ice may be added. Further, in order to dissolve a hardly soluble product such as basic copper carbonate after etching, dipping is performed in an acid such as hydrochloric acid of about 0.1 to 10000 mol / m ^{3 for} about 0.1 seconds to 24 hours, or electrolytically. If the etching is performed for about 0.1 second to about 10 minutes, the bonding strength with the resin substrate is improved by about 2 to 3%.

Next, when the cross section of the etched copper foil surface was observed with an electron microscope, as shown in FIG. 2, polygonal columnar irregularities were observed. The space density occupied by the uneven portions in the surface layer was about 50%. In the copper foils etched in Examples 2 to 17 below, unevenness having a similar shape was observed.

Example 2 As an additive for supplying 3000 mol / m ³ of sodium chloride and an anion capable of forming a hardly soluble compound by reacting with copper ions, 0.2% by mass of ammonium fluoride was added to water. In an electrolyte dissolved in water, copper foil was used for the electrode on the sample side and carbon was used for the other electrode.
When etching was performed at a current density of 170 mA / cm ² at an alternating current of Hz for 5 minutes, the surface roughness Ra was 10 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 3
4.3N. A similar tendency was observed with epoxy and rubber adhesives.

The amount of ammonium fluoride added is 0.01
There was an effect at mass% or more. Claim 3 further as an additive.
The same effect was obtained by adding 0.01 to 5% by mass of those described in (1). The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed to another one. It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult. Almost the same result was obtained even when the etching time was 1 hour.

(Example 3) As an additive for supplying 3000 mol / m ³ of sodium chloride and an anion capable of forming a hardly soluble compound by reacting with copper ion, 0.2% by mass of ammonium phosphate was added to water. In the dissolved electrolyte, copper foil was used for the electrode on the sample side, and carbon was used for the other electrode.
When etching was performed for 5 minutes at a current density of 170 mA / cm ² with an alternating current of z, the surface roughness Ra was 9 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching. The rest is 31.4
It became N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed for phosphoric acid and other phosphates.

The effect was effective when the addition amount of ammonium phosphate was 0.01% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed it to the one. It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult.

An etching current of 680 mA at an alternating current of 1 Hz
/ Cm ² and an etching time of 5 seconds to obtain a surface roughness Ra of 3 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 18.
6N. A similar tendency was observed with epoxy and rubber adhesives.

Example 4 As an additive for supplying 3000 mol / m ³ of sodium chloride and an anion capable of forming a hardly soluble compound by reacting with copper ions, 0.2% by mass of ammonium pyrophosphate was added to water. Using a copper foil for the electrode on the sample side and carbon for the other electrode, etching was performed for 5 minutes at a current density of 170 mA / cm ² with an alternating current of 1 Hz using a copper foil for the electrode on the sample side and carbon for the other electrode in the electrolytic solution dissolved in As a result, the surface roughness Ra was 8 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 3
7.2N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed for pyrophosphate and other pyrophosphates.

The amount of ammonium pyrophosphate added is 0.0
There was an effect at 1% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed to another one. It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult.

Example 5 As an additive for supplying 3000 mol / m ³ of sodium chloride and an anion capable of reacting with copper ions to form a hardly soluble compound, 0.2% by mass of ammonium iodoate was added to water. Using a copper foil for the electrode on the sample side and carbon for the other electrode, etching was performed for 5 minutes at a current density of 170 mA / cm ² with an alternating current of 1 Hz using a copper foil for the electrode on the sample side and carbon for the other electrode in the electrolytic solution dissolved in As a result, the surface roughness Ra was 7 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 3
1.4N. A similar tendency was observed with epoxy and rubber adhesives.

The amount of ammonium iodoate added is 0.0
There was an effect at 1% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed to another one. It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult.

Example 6 0.2% by mass of ammonium oxalate was added to water as an additive for supplying 3000 mol / m ³ of sodium chloride and an anion capable of forming a hardly soluble compound by reacting with copper ions. In the dissolved electrolyte, copper foil was used for the electrode on the sample side, and carbon was used for the other electrode.
When etching was performed at a current density of 170 mA / cm ² for 5 minutes with an alternating current of z, the surface roughness Ra was 8 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 26.5
It became N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed for oxalic acid and other oxalates.

The effect was effective when the amount of ammonium oxalate added was 0.01% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed it to the one. It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult.

Example 7 0.2% by mass of ammonium formate was added to water as an additive to supply 3000 mol / m ³ of sodium chloride and an anion capable of forming a hardly soluble compound by reacting with copper ions. In the dissolved electrolyte, copper foil was used for the electrode on the sample side, and carbon was used for the other electrode.
When etching was performed for 5 minutes at a current density of 170 mA / cm ² with an alternating current of z, the surface roughness Ra was 9 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching. The rest is 28.4
It became N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed with formic acid and other formate salts.

An effect was obtained when the amount of ammonium formate added was 0.01% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed it to the one. It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult.

Example 8 As an additive for supplying 3000 mol / m ³ of sodium chloride and an anion capable of reacting with copper ions to form a hardly soluble compound, 0.2% by mass of ammonium metaphosphate was added to water. Using a copper foil for the electrode on the sample side and carbon for the other electrode, etching was performed for 5 minutes at a current density of 170 mA / cm ² with an alternating current of 1 Hz using a copper foil for the electrode on the sample side and carbon for the other electrode in the electrolytic solution dissolved in As a result, the surface roughness Ra was 8 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 2
It became 7.4N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed for metaphosphoric acid and other metaphosphates.

The amount of ammonium metaphosphate added is 0.0
There was an effect at 1% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed to another one. It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult.

Example 9 As an additive for supplying 3000 mol / m ³ of potassium chloride and an anion capable of reacting with copper ions to form a hardly soluble compound, 0.2% by mass of ammonium formate was added to water. In the melted electrolytic solution, copper foil was used for the electrode on the sample side, and carbon was used for the other electrode.
When etching was performed at a current density of 170 mA / cm ² for 5 minutes with an alternating current of, the surface roughness Ra was 9 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching. The rest is 34.3
It became N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed with formic acid and other formate salts.

The effect was effective when the amount of ammonium formate added was 0.01% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed it to the one.

Example 10 As an additive for supplying 3000 mol / m ³ of lithium chloride and an anion capable of forming a hardly soluble compound by reacting with copper ions, 0.2% by mass of ammonium metaphosphate was added to water. In an electrolyte dissolved in water, copper foil was used for the electrode on the sample side and carbon was used for the other electrode.
When etching was performed at a current density of 170 mA / cm ² for 5 minutes with an alternating current of Hz, the surface roughness Ra was 8 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching. After 26.
5N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed for metaphosphoric acid and other metaphosphates.

The amount of ammonium metaphosphate added is 0.0
There was an effect at 1% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed to another one. As an additive, it is preferable to form a hardly soluble salt or an insoluble salt with copper, and it goes without saying that a similar effect can be expected with various additives.

Example 11 As an additive for supplying 3000 mol / m ³ of potassium bromide and an anion capable of forming a hardly soluble compound by reacting with copper ions, 0.2% by mass of ammonium formate was added to water. In an electrolytic solution dissolved in water, copper foil was used for the electrode on the sample side, and carbon was used for the other electrode.
When etching was performed at a current density of 170 mA / cm ² for 5 minutes with an alternating current of, the surface roughness Ra was 9 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching. The rest is 31.4
It became N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed with formic acid and other formate salts.

The effect was effective when the amount of ammonium formate added was 0.01% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed it to the one.

Example 12 As an additive for supplying 3000 mol / m ³ of potassium bromide and an anion capable of forming a hardly soluble compound by reacting with copper ions, 0.01% by mass of ammonium formate was added to water. In an electrolytic solution dissolved in water, copper foil was used for the electrode on the sample side, and carbon was used for the other electrode.
When etching was performed for 5 minutes at a current density of 170 mA / cm ² with an alternating current of z, the surface roughness Ra was 6 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 22.5
It became N. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed with formic acid and other formate salts. The salt in the electrolyte is also described in claim 2.
There was no big difference when I changed it to the one.

Example 13 As an additive for supplying 3000 mol / m ³ of potassium bromide and an anion capable of forming a hardly soluble compound by reacting with copper ion, 0.001% by mass of ammonium formate was added to water. In an electrolyte dissolved in water, copper foil was used for the electrode on the sample side and carbon was used for the other electrode.
When etching was performed for 5 minutes at a current density of 170 mA / cm ² with an alternating current of Hz, the surface roughness Ra was 1.5 μm.
Met. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 1
5.7 N, and there was no significant effect. Epoxy,
A similar tendency was observed for the rubber adhesive. A similar tendency was observed with formic acid and other formate salts. There was no significant difference when the salt in the electrolyte was changed to another one described in claim 2 . It is desirable that the concentration of both the electrolyte and the additive be a saturated solution, but there is no problem even if a precipitate is present.

Example 14 As an additive for supplying 1 mol / m ³ of potassium bromide and an anion capable of forming a hardly soluble compound by reacting with copper ions, 0.05% by mass of ammonium formate was added to water. Using a copper foil for the electrode on the sample side and carbon for the other electrode, etching was performed for 5 minutes at a current density of 170 mA / cm ² with an alternating current of 1 Hz using a copper foil for the electrode on the sample side and carbon for the other electrode in the electrolytic solution dissolved in As a result, the surface roughness Ra was 5 μm. Vertical 3 using alpha cyanoacrylate based instant adhesive
When a tensile test was performed using a copper foil having a thickness of 0.1 mm, a width of 3 mm and a thickness of 0.1 mm, the tensile strength was 1 before etching.
Although it was 4.7N, it became 22.5N after etching. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed with formic acid and other formate salts.

The effect was effective when the amount of ammonium formate added was 0.01% by mass or more. The same effect was obtained even when 0.01 to 5% by mass of the additive described in claim 3 was further added as an additive. Salts in the electrolyte are also potassium iodide, paratoluene
Even if it is changed to sulfone soda, sodium perchlorate, etc.
There was no difference.

Example 15 0.05% by mass of ammonium formate as an additive for supplying 0.1 mol / m ³ of potassium bromide and an anion capable of reacting with copper ions to form a hardly soluble compound In an electrolytic solution of water in water, using copper foil for the electrode on the sample side and carbon for the other electrode, and 1 Hz for a sample 60 mm long and 60 mm wide.
When etching was performed at a current density of 17 mA / cm ² for 50 minutes with an alternating current of, the surface roughness Ra was 1.7 μm. When a tensile test was performed on a copper foil having a length of 3 mm, a width of 3 mm, and a thickness of 0.1 mm using an alpha cyanoacrylate instant adhesive, the tensile strength was 14.7 N before etching, but the etching was After 16.
7N, no significant effect. A similar tendency was observed with epoxy and rubber adhesives. A similar tendency was observed with formic acid and other formate salts. Request for salt in electrolyte
No significant difference was found even when the composition was changed to another one described in item 2 .
It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar tendency was obtained in DC etching.

Example 16 0.2% by mass of aqueous ammonia was added as an additive for supplying 3000 mol / m ³ of potassium bromide and an anion capable of forming a hardly soluble compound by reacting with copper ions. In the prepared electrolyte, a sample of 60 mm in length and 60 mm in width was etched at a current density of 170 mA / cm ² at an alternating current of 1 Hz for 5 minutes using copper foil as an electrode on the sample side and carbon as another electrode. However, the surface roughness Ra was 9 μm. 3m long using alpha cyanoacrylate instant adhesive
When a tensile test was performed using a copper foil having a width of 3 mm and a width of 3 mm and a thickness of 0.1 mm, the tensile strength was 1 before etching.
Although it was 4.7N, it became 26.5N after etching. A similar tendency was observed with epoxy and rubber adhesives.

Similar effects were obtained by adding 0.01 to 5% by mass of the additive described in claim 3 as an additive. There was no significant difference when the salt in the electrolyte was changed to another one described in claim 2 . It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult. Almost the same result was obtained even when the etching time was 1 hour. The concentration of ammonia water was effective at 0.01 to 5% by mass.

Example 17 Carbon dioxide gas was bubbled at 5 dm ³ / min as an additive for supplying 3000 mol / m ³ of potassium bromide and anions capable of forming a hardly soluble compound by reacting with copper ions. A sample of 60 mm long and 60 mm wide was etched with a current of 170 mA / cm ² at an alternating current of 1 Hz for 5 minutes using a copper foil for the electrode on the sample side and carbon for the other electrode in the electrolytic solution. And the surface roughness Ra was 9 μm. 3m long using alpha cyanoacrylate instant adhesive
When a tensile test was performed using a copper foil having a width of 3 mm and a width of 3 mm and a thickness of 0.1 mm, the tensile strength was 1 before etching.
Although it was 4.7N, it became 26.5N after etching. A similar tendency was observed with epoxy and rubber adhesives.

The same effect was obtained by adding 0.01 to 5% by mass of the additive described in claim 3 as an additive. There was no significant difference when the salt in the electrolyte was changed to another one described in claim 2 . It goes without saying that the present invention can be applied to either one side or both sides of the copper foil. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult. The carbon dioxide gas flow rate was effective from 0.01 dm ³ / min.

Example 18 As shown in FIG. 2, the copper foil having the polygonal columnar surface portion etched in Examples 1 to 17 was re-etched to change the three-dimensional shape of the copper foil surface portion into a polygonal trapezoidal shape. Or, it becomes a polygonal pyramid, and can withstand one side of the capacitor electrode by improving the withstand voltage, so that the capacitor can be built in.

In a 3000 mol / m ³ HCl electrolytic solution, a copper foil was used for the electrode on the sample side and carbon was used for the other electrode.
A sample of 60 mm length and 60 mm width is 170
When re-etching was performed at a current density of mA / cm ² for 30 seconds, the surface roughness Ra was 6 μm. 3mm long using alpha cyanoacrylate instant adhesive,
When a tensile test was performed on a copper foil having a width of 3 mm and a thickness of 0.1 mm, the tensile strength was 14.7 before etching.
Although it was N, it became 19.6N after etching.
A similar tendency was observed with epoxy and rubber adhesives.

In addition to hydrochloric acid, water-soluble acids such as sulfuric acid, perchloric acid, sulfonic acids and nitric acid, and water-soluble alkalis such as caustic soda and caustic potash were also effective.
Acids capable of etching copper such as nitric acid, salts such as ferric chloride, and acids, salts or alkalis to which an oxidizing agent such as hydrogen peroxide is added have also been effective.

When the salt in the electrolytic solution was changed to the one described in claim 2, the polygonal column-shaped etching tended to be deeper than the polygonal trapezoidal or polygonal pyramid. However, even if another salt described in claim 2 is used as the salt in the electrolytic solution, it is also possible to use a salt according to claim 3
If the addition of at most 0.0090% by mass of ammonium bicarbonate as an additive described in (1) was suppressed, the polygonal column-shaped etching did not deepen. This was the same for the other additives described in claim 3.

When this neutral salt is used, it may be treated or etched with an acid or alkali to remove the precipitate. It goes without saying that either one side or both sides of the copper foil can be applied. Changing the bath temperature had no significant effect. A similar effect was obtained by DC etching, but process control was difficult. Needless to say, the finer etching can be performed by performing the etching three or more times.

Next, when the cross section of the etched copper foil surface was observed with an electron microscope, as shown in FIG. 3, trapezoidal polygonal irregularities were observed.

(Example 19) The copper foil having the polygonal columnar surface portion etched in Examples 1 to 18 was re-etched, so that the three-dimensional shape of the copper foil surface portion became a polygonal trapezoidal shape or a polygonal pyramid shape. By improving the withstand voltage, one side of the capacitor electrode can be provided, and the capacitor can be built in.

In order to form a 10 mm square by 10 mm square capacitor with a sample of 60 mm length and 60 mm width before etching, polyethylene terephthalate (P
ET) was deposited. Other electrodes were prepared by applying resin-mixed silver, electrolytic polymerization of polypyrrole and thiophene and vapor deposition to obtain several pF. In the combination of Example 1 and Example 18, the capacitance was ten and several pF, which is five times that before etching.

[0067]

According to the present invention, by performing electrolytic etching in an electrolytic solution to produce copper having a roughened surface as described above, a roughened surface having a fractured column shape, a polygonal trapezoidal shape, or a polygonal pyramid shape is obtained. It became possible to obtain a surface. As a result, roughened copper can be obtained at low cost, and a capacitor with a large surface area can be built in. In addition, the delay is reduced even at high frequencies, and the multilayer printed circuit board or PT
It has become possible to manufacture the C characteristic current protection element at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic view of a copper foil surface subjected to conventional roughening plating.

FIG. 2 is a schematic view of a copper foil surface etched according to the present invention.

FIG. 3 is a schematic view of a copper foil surface re-etched according to the present invention.

FIG. 4 is a schematic view of an etching tank used in the present invention.

[Explanation of symbols]

 1 electrode 2 other electrode (sample) 3 electrolyte 4 power supply

Continuing on the front page (72) Inventor Masakazu Tanahashi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. ) References JP-A-2000-204500 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25F 3/02 H05K 1/03 630 H05K 3/38

Claims (10)

(57) [Claims] 1. A copper foil or a copper plate having an uneven portion having a height of 1 to 20 μm on a surface layer portion, wherein a space density occupied by the uneven portion in the surface layer portion is 10% or more and 90% or less. Characterized surface roughened copper. 2. At least one salt selected from the group consisting of sodium chloride, potassium chloride, sodium nitrate, potassium nitrate, magnesium sulfate, sodium carbonate and sodium bicarbonate reacts with copper ions to be hardly soluble.
Surface roughened copper obtained by etching the surface of a copper foil or a copper plate in an electrolytic solution containing an anion capable of forming a compound of
Before the addition amount of the anion is 0.0090% by mass or less
A method for producing surface roughened copper, wherein etching is performed again in the electrolytic solution . 3. The anion is selected from the group consisting of carbonate ion, fluorine ion, hydrogen carbonate ion, hydroxide ion, phosphate ion, pyrophosphate ion, iodoate ion, oxalate ion, formate ion and metaphosphate ion. 3. The method for producing surface roughened copper according to claim 2, wherein the method is at least one kind. 4. The method according to claim 2, wherein the etching is AC etching. 5. The method according to claim 4, wherein an AC frequency used for the AC etching is 50 Hz or less. 6. The method for producing a surface-roughened copper according to claim 2, wherein a small piece of carbon dioxide gas or dry ice by bubbling is added as an additive to the electrolytic solution. 7. The method of claim 2 the surface roughness of copper was prepared by the method of any one of 6, the manufacturing method of the surface roughening copper performing processing or etching with acid or alkaline solutions. 8. A printed circuit board comprising the surface-roughened copper according to claim 1 as a conductor. 9. A printed circuit board with a surface roughness of copper was prepared by the method of any of claims 2-7 as a conductor. 10. A printed circuit board which has incorporated a condenser to a printed circuit board according to claim 8 or 9.